Browsing by Subject "Nanoparticles"
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Item Open Access Assessing cardiac injury in mice with dual energy-microCT, 4D-microCT, and microSPECT imaging after partial heart irradiation.(Int J Radiat Oncol Biol Phys, 2014-03-01) Lee, Chang-Lung; Min, Hooney; Befera, Nicholas; Clark, Darin; Qi, Yi; Das, Shiva; Johnson, G Allan; Badea, Cristian T; Kirsch, David GPURPOSE: To develop a mouse model of cardiac injury after partial heart irradiation (PHI) and to test whether dual energy (DE)-microCT and 4-dimensional (4D)-microCT can be used to assess cardiac injury after PHI to complement myocardial perfusion imaging using micro-single photon emission computed tomography (SPECT). METHODS AND MATERIALS: To study cardiac injury from tangent field irradiation in mice, we used a small-field biological irradiator to deliver a single dose of 12 Gy x-rays to approximately one-third of the left ventricle (LV) of Tie2Cre; p53(FL/+) and Tie2Cre; p53(FL/-) mice, where 1 or both alleles of p53 are deleted in endothelial cells. Four and 8 weeks after irradiation, mice were injected with gold and iodinated nanoparticle-based contrast agents, and imaged with DE-microCT and 4D-microCT to evaluate myocardial vascular permeability and cardiac function, respectively. Additionally, the same mice were imaged with microSPECT to assess myocardial perfusion. RESULTS: After PHI with tangent fields, DE-microCT scans showed a time-dependent increase in accumulation of gold nanoparticles (AuNp) in the myocardium of Tie2Cre; p53(FL/-) mice. In Tie2Cre; p53(FL/-) mice, extravasation of AuNp was observed within the irradiated LV, whereas in the myocardium of Tie2Cre; p53(FL/+) mice, AuNp were restricted to blood vessels. In addition, data from DE-microCT and microSPECT showed a linear correlation (R(2) = 0.97) between the fraction of the LV that accumulated AuNp and the fraction of LV with a perfusion defect. Furthermore, 4D-microCT scans demonstrated that PHI caused a markedly decreased ejection fraction, and higher end-diastolic and end-systolic volumes, to develop in Tie2Cre; p53(FL/-) mice, which were associated with compensatory cardiac hypertrophy of the heart that was not irradiated. CONCLUSIONS: Our results show that DE-microCT and 4D-microCT with nanoparticle-based contrast agents are novel imaging approaches complementary to microSPECT for noninvasive assessment of the change in myocardial vascular permeability and cardiac function of mice in whom myocardial injury develops after PHI.Item Open Access Assessing the Impacts of Silver Nanoparticles on the Growth, Diversity, and Function of Wastewater Bacteria(2012) Arnaout, Christina LeeSilver nanoparticles (AgNPs) are increasingly being integrated into a wide range of consumer products, such as air filters, washing machines, and textiles, due to their antimicrobial properties [1]. However, despite the beneficial applications of AgNPs into consumer products, it is likely that their use will facilitate the release of AgNPs into wastewater treatment plants, thereby possibly negatively impacting key microorganisms involved in nutrient removal. For this reason, it is important to characterize the effects of AgNPs in natural and engineered systems and to measure the antimicrobial effect of AgNPs on wastewater microorganisms. Polyvinyl alcohol coated AgNPs have already been linked to decreased nitrifying activity [2] and it is important to determine if AgNPs coated with other materials follow similar trends. Furthermore, it is likely that, with repeated exposure to AgNPs microbial communities could evolve and develop resistance to silver. Thus, a long-term effect of silver nanoparticle exposure could be a reduction of the efficacy of such products in a similar fashion to the development of microbial antibiotic resistance [3]. Therefore, it is critical that the impacts of these materials be ascertained in wastewater treatment systems to prevent long-term negative effects.
The objectives of this dissertation were to: 1) characterize the effect of several different AgNPs on the ammonia oxidizing bacterium (AOB) Nitrosomonas europaea and investigate possible mechanisms for toxicity, 2) test the effects of consumer product AgNPs on a wide range of heterotrophic bacteria, 3) evaluate the effects of AgNPs on bench scale wastewater sequencing batch reactors, and lastly 4) assess the impacts on microbial communities that are applied with AgNP spiked wastewater biosolids.
First, Nitrosomonas europaea was was selected because wastewater nitrifying microorganisms carry out the first step in nitrification and are known to be sensitive to a wide range of toxicants [4].The antimicrobial effects of AgNPs on the AOB N. europaea were measured by comparing nitrite production rates in a dose response assay and analyzing cell viability using the LIVE/DEAD® fluorescent staining assay. AgNP toxicity to N. europaea appeared to be largely nanoparticle coating dependent. While PVP coated AgNPs have shown reductions up to 15% in nitrite production at 20 ppm, other AgNPs such as gum arabic (GA) coated showed the same level of inhibition at concentrations of 2 ppm. The first mechanism of inhibition appears to be a post-transcriptional interference of AMO/HAO by either dissolved Ag or ROS, in treatments where membranes are not completely disrupted but nitrite production decreased (2 ppm GA AgNP and 2 ppm PVP AgNP treatments). The disruption of nitrification is dependent on AgNP characteristics, such as zeta potential and coating, which will dictate how fast the AgNP will release Ag+ and ROS production Finally, total membrane loss and release of internal cellular matter occur.
In order to test the effects of AgNP products available to consumers, simple bacterial toxicity tests were carried out on well-studied heterotrophic bacteria. A model gram-positive and gram-negative bacterium (B. subtilis and E. coli, respectively) was selected to assess any differences in sensitivity that may occur with the exposure to AgNPs. A third model gram-negative bacterium (P. aeruginosa) was chosen for its biofilm forming capabilities. In addition to testing pure nanoparticles, three silver supplements meant for ingestion, were randomly chosen to test with these three bacteria. Growth curve assays and LIVE/DEAD staining indicate that the consumer product AgNPs had the most significant inhibition on growth rates, but not membrane integrity. Overall, P. aeruginosa was most negatively affected by all AgNPs with nearly 100% growth inhibition for all 2 ppm AgNP treatments. TEM imaging also confirmed cell wall separation in P. aeruginosa and internal density differences for E. coli. The effects on B. subtilis, a gram-positive bacterium, were not as severe but toxicity was observed for several AgNPs at concentrations greater than 2 ppm. Citrate AgNPs appeared to have the most impact on membrane integrity, while other mechanisms such as internal thiol binding might have been at work for other AgNPs.
The effects of varying concentrations of pure AgNPs on complex microbial wastewater reactors are currently being tested. Eight bench-scale sequencing batch reactors were set up to follow the typical "fill, react, settle, decant, idle" method with an 8 hour hydraulic retention time and constant aeration. Reactors were fed synthetic wastewater and treatment efficiency is measured by monitoring effluent concentrations of COD, NH4+, and NO3-. The reactors were seeded with 500 mL of activated sludge from a local wastewater treatment plant. After reaching steady state, the reactors were spiked with 0.2 ppm gum arabic and citrate coated AgNPs. Treatment efficiency was monitored and results showed significant spikes and ammonia and COD immediately following the first spike, but the microbial community appeared to adapt for future AgNP spikes. Microbial community analysis (terminal restriction fragment length polymorphism) showed confirmed this hypothesis.
Overall, this dissertation asserts that by examining AgNP coating type, Ag+ dissolution rates and Stern layer surface charge, it may be possible to predict which AgNPs may be more detrimental wastewater treatment, but not all AgNPs will have the same effect. The results obtained herein must be expanded to other types of AgNPs and microorganisms of ecological importance.
Item Embargo Bioengineering Microporous Annealed Particle Scaffolds to Recruit Neural Progenitor Stem Cells and Promote Angiogenesis in the Stroke Core(2022) Wilson, KatrinaThere remains a significant gap in the need for regenerative therapies for stroke compared to what is currently available. An ideal therapy would be one that stimulates the formation of new tissue with the ability to regain any function previously lost due to stroke. Therefore, methods exploiting the plasticity of the brain and modulating endogenous cellular responses to promote repair in the stroke core after ischemia have become highly attractive. However, this process of neural regeneration is complex and requires a series of controlled biological events, such as recruitment and differentiation of neuron progenitor cells (NPC’s), angiogenesis, and axonogenesis. Biomaterials are now commonly used to research tissue regeneration and cellular mechanisms, both in vitro and in vivo. We have designed a biocompatible biomaterial from macroporous annealed particles (MAP) hydrogels for injection into the stroke core five days after a photothrombotic stroke. Our hyaluronic acid-based material has been modified to dictate NPC fate in vitro through maintained stemness and the formation of neurospheres or towards Tuj1 positive NPCs, as well as enhance angiogenesis and the recruitment of endogenous NPCs after stroke. We have observed the first case of significant angiogenesis throughout the entire stroke core within only 10 days after injection, or 15 days post stroke. As well as significant increase in Tuj1+ and Nestin+ cells.
Item Open Access Biomimetic nanoparticles with enhanced affinity towards activated endothelium as versatile tools for theranostic drug delivery.(Theranostics, 2018-01-05) Martinez, Jonathan O; Molinaro, Roberto; Hartman, Kelly A; Boada, Christian; Sukhovershin, Roman; De Rosa, Enrica; Kirui, Dickson; Zhang, Shanrong; Evangelopoulos, Michael; Carter, Angela M; Bibb, James A; Cooke, John P; Tasciotti, EnnioActivation of the vascular endothelium is characterized by increased expression of vascular adhesion molecules and chemokines. This activation occurs early in the progression of several diseases and triggers the recruitment of leukocytes. Inspired by the tropism of leukocytes, we investigated leukocyte-based biomimetic nanoparticles (i.e., leukosomes) as a novel theranostic platform for inflammatory diseases. Methods: Leukosomes were assembled by combining phospholipids and membrane proteins from leukocytes. For imaging applications, phospholipids modified with rhodamine and gadolinium were used. Leukosomes incubated with antibodies blocking lymphocyte function-associated antigen 1 (LFA-1) and CD45 were administered to explore their roles in targeting inflammation. In addition, relaxometric assessment of NPs was evaluated. Results: Liposomes and leukosomes were both spherical in shape with sizes ranging from 140-170 nm. Both NPs successfully integrated 8 and 13 µg of rhodamine and gadolinium, respectively, and demonstrated less than 4% variation in physicochemical features. Leukosomes demonstrated a 16-fold increase in breast tumor accumulation relative to liposomes. Furthermore, quantification of leukosomes in tumor vessels demonstrated a 4.5-fold increase in vessel lumens and a 14-fold increase in vessel walls. Investigating the targeting mechanism of action revealed that blockage of LFA-1 on leukosomes resulted in a 95% decrease in tumor accumulation. Whereas blockage of CD45 yielded a 60% decrease in targeting and significant increases in liver and spleen accumulation. In addition, when administered in mice with atherosclerotic plaques, leukosomes exhibited a 4-fold increase in the targeting of inflammatory vascular lesions. Lastly, relaxometric assessment of NPs demonstrated that the incorporation of membrane proteins into leukosomes did not impact the r1 and r2 relaxivities of the NPs, demonstrating 6 and 30 mM-1s-1, respectively. Conclusion: Our study demonstrates the ability of leukosomes to target activated vasculature and exhibit superior accumulation in tumors and vascular lesions. The versatility of the phospholipid backbone within leukosomes permits the incorporation of various contrast agents. Furthermore, leukosomes can potentially be loaded with therapeutics possessing diverse physical properties and thus warrant further investigation toward the development of powerful theranostic agents.Item Open Access Brachytherapy via a depot of biopolymer-bound 131I synergizes with nanoparticle paclitaxel in therapy-resistant pancreatic tumours.(Nature biomedical engineering, 2022-10) Schaal, Jeffrey L; Bhattacharyya, Jayanta; Brownstein, Jeremy; Strickland, Kyle C; Kelly, Garrett; Saha, Soumen; Milligan, Joshua; Banskota, Samagya; Li, Xinghai; Liu, Wenge; Kirsch, David G; Zalutsky, Michael R; Chilkoti, AshutoshLocally advanced pancreatic tumours are highly resistant to conventional radiochemotherapy. Here we show that such resistance can be surmounted by an injectable depot of thermally responsive elastin-like polypeptide (ELP) conjugated with iodine-131 radionuclides (131I-ELP) when combined with systemically delivered nanoparticle albumin-bound paclitaxel. This combination therapy induced complete tumour regressions in diverse subcutaneous and orthotopic mouse models of locoregional pancreatic tumours. 131I-ELP brachytherapy was effective independently of the paclitaxel formulation and dose, but external beam radiotherapy (EBRT) only achieved tumour-growth inhibition when co-administered with nanoparticle paclitaxel. Histological analyses revealed that 131I-ELP brachytherapy led to changes in the expression of intercellular collagen and junctional proteins within the tumour microenvironment. These changes, which differed from those of EBRT-treated tumours, correlated with the improved delivery and accumulation of paclitaxel nanoparticles within the tumour. Our findings support the further translational development of 131I-ELP depots for the synergistic treatment of localized pancreatic cancer.Item Open Access Characterizing and predicting the interaction of proteins with nanoparticles(2023) Poulsen, KarstenNanoparticles are being used or implemented in a wide array of applications including health care, cosmetics, automotive, food, beverage, coatings, consumer electronics, and coatings. Despite this widespread use, we are unable to predict how nanoparticles will interact with biological systems. This is important for both nanotoxicity resulting from human exposure to nanomaterials and the development of new nano-based biotechnologies. The first step in the interaction of nanoparticles with biological systems is often with blood, for biomedical applications, or lung fluid, when nanoparticles are inhaled. In both cases, the nanoparticles are exposed to proteins that form a "corona" by adsorbing on the nanoparticle surface. The subsequent cellular response is determined by this protein corona rather than the bare nanoparticle.Our goal is to develop a predictive capability for protein-nanoparticle interactions. This requires lab automation, large datasets, machine learning, and mechanistic studies. We first developed and validated a semi-automated approach to generate, purify, and characterize protein coronas using a liquid handling robot and low-cost proteomics. Using this semi-automated approach, we characterized the formation of protein coronas with increasing incubation time and serum concentration. Incubation time was found to be an important parameter for corona composition and concentration at high incubation concentrations but yielded only a small effect at low serum incubation concentrations. To better understand how the protein corona affects biological responses, we investigated the response of macrophage cells to titanium dioxide nanoparticles as a function of the protein corona. As in our previous work with serum proteins, we measured the concentration and composition of murine lung fluid proteins adsorbed on the surface of titanium dioxide nanoparticles. We found that a low concentration of lung fluid corona, relative to fetal bovine serum and bovine serum albumin coronas, led to an increased expression of cytokines (interleukin 6 (IL-6), tumor necrosis factor-alpha (TNF-α), and macrophage inflammatory protein 2 (MIP-2)), indicating an inflammation response. This underscores the importance of understanding how the composition and concentration of the protein corona governs organism responses to nanoparticle exposures. Our validated high-throughput lab automation work allowed us to synthesize a library of magnetic nanoparticles and characterize their resulting protein coronas. The resulting nanoparticle dataset has 12 unique NP surfaces, seven surface charges, two core sizes, and two core materials. We used this dataset to generate and characterize, via proteomics, a variety of protein coronas varying incubation concentration and purification methods. We used the resulting proteomic dataset in conjunction with a database of protein physicochemical properties to build a machine learning model that identifies the most important nanoparticle and protein properties for protein corona formation. The model was tested using external datasets and found that it can predict human serum and lung fluid coronas on varying nanoparticle surfaces. Overall, this combination of lab automation, machine learning, and mechanistic analysis suggests that a generalizable understanding of the protein corona formation and its effects is forthcoming.
Item Open Access Computed tomography imaging of primary lung cancer in mice using a liposomal-iodinated contrast agent.(PLoS One, 2012) Badea, CT; Athreya, KK; Espinosa, G; Clark, D; Ghafoori, AP; Li, Y; Kirsch, DG; Johnson, GA; Annapragada, A; Ghaghada, KBPURPOSE: To investigate the utility of a liposomal-iodinated nanoparticle contrast agent and computed tomography (CT) imaging for characterization of primary nodules in genetically engineered mouse models of non-small cell lung cancer. METHODS: Primary lung cancers with mutations in K-ras alone (Kras(LA1)) or in combination with p53 (LSL-Kras(G12D);p53(FL/FL)) were generated. A liposomal-iodine contrast agent containing 120 mg Iodine/mL was administered systemically at a dose of 16 µl/gm body weight. Longitudinal micro-CT imaging with cardio-respiratory gating was performed pre-contrast and at 0 hr, day 3, and day 7 post-contrast administration. CT-derived nodule sizes were used to assess tumor growth. Signal attenuation was measured in individual nodules to study dynamic enhancement of lung nodules. RESULTS: A good correlation was seen between volume and diameter-based assessment of nodules (R(2)>0.8) for both lung cancer models. The LSL-Kras(G12D);p53(FL/FL) model showed rapid growth as demonstrated by systemically higher volume changes compared to the lung nodules in Kras(LA1) mice (p<0.05). Early phase imaging using the nanoparticle contrast agent enabled visualization of nodule blood supply. Delayed-phase imaging demonstrated significant differential signal enhancement in the lung nodules of LSL-Kras(G12D);p53(FL/FL) mice compared to nodules in Kras(LA1) mice (p<0.05) indicating higher uptake and accumulation of the nanoparticle contrast agent in rapidly growing nodules. CONCLUSIONS: The nanoparticle iodinated contrast agent enabled visualization of blood supply to the nodules during the early-phase imaging. Delayed-phase imaging enabled characterization of slow growing and rapidly growing nodules based on signal enhancement. The use of this agent could facilitate early detection and diagnosis of pulmonary lesions as well as have implications on treatment response and monitoring.Item Open Access Delivery of an ectonucleotidase inhibitor with ROS-responsive nanoparticles overcomes adenosine-mediated cancer immunosuppression.(Science translational medicine, 2022-06) Mao, Chengqiong; Yeh, Stacy; Fu, Juan; Porosnicu, Mercedes; Thomas, Alexandra; Kucera, Gregory L; Votanopoulos, Konstantinos I; Tian, Shaomin; Ming, XinTumor evasion of immune destruction is associated with the production of immunosuppressive adenosine in the tumor microenvironment (TME). Anticancer therapies can trigger adenosine triphosphate (ATP) release from tumor cells, causing rapid formation of adenosine by the ectonucleotidases CD39 and CD73, thereafter exacerbating immunosuppression in the TME. The goal of this study was to develop an approach to facilitate cancer therapy-induced immunogenic cell death including ATP release and to limit ATP degradation into adenosine, in order to achieve durable antitumor immune response. Our approach was to construct reactive oxygen species (ROS)-producing nanoparticles that carry an ectonucleotidase inhibitor ARL67156 by electronic interaction and phenylboronic ester. Upon near-infrared irradiation, nanoparticle-produced ROS induced ATP release from MOC1 cancer cells in vitro and triggered the cleavage of phenylboronic ester, facilitating the release of ARL67156 from the nanoparticles. ARL67156 prevented conversion of ATP to adenosine and enhanced anticancer immunity in an MOC1-based coculture model. We tested this approach in mouse tumor models. Nanoparticle-based ROS-responsive drug delivery reprogramed the immunogenic landscape in tumors, eliciting tumor-specific T cell responses and tumor regression, conferring long-term survival in mouse models. We demonstrated that TME reprograming sets the stage for response to anti-programmed cell death protein 1 (PD1) immunotherapy, and the combination resulted in tumor regression in a 4T1 breast cancer mouse model that was resistant to PD1 blockade. Furthermore, our approach also induced immunological effects in patient-derived organotypic tumor spheroid model, suggesting potential translation of our nanoparticle approach for treating human cancers.Item Open Access Deposition of Nano-scale Particles in Aqueous Environments --Influence of Particle Size, Surface Coating, and Aggregation State(2012) Lin, ShihongThis work considers the transport and attachment of nanoscale particles to surfaces and the associated phenomena that dictate particle-surface interactions. A consideration of the deposition of nano-scale particles on surfaces is a natural outgrowth of more than a century of research in the area of colloid science, and has taken on new pertinence in the context of understanding the fate and transport of engineered nanoparticles in aqueous environments. More specifically, the goal of this work is to better understand the effects of particle size, surface polymer coatings, and aggregation state on the kinetics of nanoparticle deposition. Theoretical tools such as those developed by Derjaguin-Landau-Verwey-Overbeek (DLVO) and Flory-Krigbaum , as well as the soft particle theory and surface element integration scaling methods are employed to address certain problems that were not considered with the existing theoretical frameworks for the conventional colloidal problems. Consequences of theoretical predictions are evaluated experimentally using column experiments or the quartz crystal microbalance techniques to monitor deposition kinetics. One of the key findings of this work is the observation that polymer coatings may stabilize nanoparticles against deposition or increase deposition, depending on whether the polymer coatings exist on both of the interacting surfaces and the interaction between the polymer and the collector surface. Both steric and bridging mechanisms are possible depending on whether contact between the polymer and collector surface can result in successful attachment. In addition, limitations in the use of conventional, equilibrium-based DLVO theory to describe the deposition of nano-scale particles at very low ionic strength are also identified and discussed. Moreover, it is demonstrated that the interaction between the aggregated nano-scale particles and environmental surfaces is controlled by the characteristic size of the primary particles rather than that of the aggregates. Thus despite an increase in hydrodynamic diameter, aggregation is predicted to reduce deposition only from the hydrodynamic aspects, but not from the colloidal interaction aspect. The affinity between aggregated nanoparticles and a surface may be increased at the initial stage of deposition while being unaffected by aggregation state during later stages of deposition. The results of this study lead to better understandings, at least on a qualitative level, of the factors that controlling the kinetics of deposition and, in a broader sense, the fate and transport of nanoscale particles in the aqueous environment.
Item Open Access Drug Delivery and Anti-Vascular Effects of Temperature Sensitive Liposomal Doxorubicin(2010) Manzoor, Ashley AnneTraditionally, the goal of nanoparticle-based chemotherapy has been to decrease normal tissue toxicity by improving drug specificity to tumor. Relying on the EPR effect (Enhanced Permeability and Retention), a host of nanoparticles (from micelles and dendrimers to liposomes and lipidic nanoparticles) have been developed and tested for passive accumulation into tumor interstitium. Unfortunately, most nanoparticles achieve only suboptimal drug delivery to tumors, due to heterogeneity of tumor vessel permeability, limited nanoparticle penetration, and relatively slow drug release. However, recent developments in nanoparticle technology have occurred with the design and testing of a fast drug-releasing liposome triggered by local heat. This temperature-sensitive liposome formulation loaded with doxorubicin (Dox-TSL) has already shown substantial anti-tumor efficacy and is currently in clinical trials.
Previous pre-clinical work to understand the mechanism of efficacy has illustrated increases in overall drug concentration in the tumor, and an anti-vascular effect not observed with heat alone. These initial studies have also suggested that these liposomes may be the most efficacious when they are injected into a pre-heated tumor, with the hypothesis that in this treatment scheme the liposomes may be releasing inside the tumor vasculature. However, whether intravascular release is indeed occurring, and the subsequent implications this paradigm change in drug delivery could have are still unanswered questions.
The experiments presented herein aimed to investigate two effects: the existence and influence of intravascular drug release on drug delivery and distribution within the tumor, and the effect of drug delivery on subsequent anti-vascular effects. To investigate drug delivery, two mouse models were used. Dorsal window chambers implanted with FaDu human squamous carcinomas were used with real-time intravital confocal microscopy to evaluate time-resolved delivery of doxorubicin and liposome extravasation over the first 20 minutes of treatment. As a complimentary mouse model, flank FaDu tumors were also treated with Dox-TSL or treatment controls (doxorubicin with and without heat and Doxil with heat), and subsequently sectioned and histologicaly imaged to evaluate drug delivery and penetration depth, as well as impact on hypoxia and perfusion parameters. To investigate vascular effects, a GFP-eNos transgenic mouse model was used, also with window chamber confocal microscopy, to evaluate morphological changes occurring in the tumor vasculature following treatment.
The results presented herein demonstrate that contrary to the traditional liposome paradigm of extravasation and subsequent drug release, thermally sensitive liposomes release drug inside the tumor vasculature, and that the released free drug diffuses into the tumor interstitium. Real-time confocal imaging of doxorubicin delivery to murine tumor window chambers illustrates that intravascular drug release provides a mechanism to increase both the time that tumor cells are exposed to maximum drug levels and the penetration distance achievable by free drug diffusion. Histological analysis further confirms this finding, illustrating that drug delivered with Dox-TSL intravascular release can result in drug penetration levels up to 80 µm from vessels, in comparison with 40 µm achievable with free drug with heat. Further, Dox-TSL delivers drug to a higher percentage of a tumor's hypoxic area than possible with free drug with or without heat. Endothelial cells display marked morphological changes apparent immediately following treatment, with significant vascular destruction at 6 hours. However, heat had a similar influence on vascular morphology, underscoring the complexity of the anti-vascular effect, particularly in the more sensitive vasculature of a mouse model compared with reported human vascular heat tolerances. This work establishes intravascular release as a new paradigm in drug delivery to solid tumors, resulting in improved drug bioavailability, penetration depth, and enhanced delivery of drug to hypoxic regions of tumors.
Item Open Access Dual-energy micro-CT functional imaging of primary lung cancer in mice using gold and iodine nanoparticle contrast agents: a validation study.(PLoS One, 2014) Ashton, Jeffrey R; Clark, Darin P; Moding, Everett J; Ghaghada, Ketan; Kirsch, David G; West, Jennifer L; Badea, Cristian TPURPOSE: To provide additional functional information for tumor characterization, we investigated the use of dual-energy computed tomography for imaging murine lung tumors. Tumor blood volume and vascular permeability were quantified using gold and iodine nanoparticles. This approach was compared with a single contrast agent/single-energy CT method. Ex vivo validation studies were performed to demonstrate the accuracy of in vivo contrast agent quantification by CT. METHODS: Primary lung tumors were generated in LSL-Kras(G12D); p53(FL/FL) mice. Gold nanoparticles were injected, followed by iodine nanoparticles two days later. The gold accumulated in tumors, while the iodine provided intravascular contrast. Three dual-energy CT scans were performed-two for the single contrast agent method and one for the dual contrast agent method. Gold and iodine concentrations in each scan were calculated using a dual-energy decomposition. For each method, the tumor fractional blood volume was calculated based on iodine concentration, and tumor vascular permeability was estimated based on accumulated gold concentration. For validation, the CT-derived measurements were compared with histology and inductively-coupled plasma optical emission spectroscopy measurements of gold concentrations in tissues. RESULTS: Dual-energy CT enabled in vivo separation of gold and iodine contrast agents and showed uptake of gold nanoparticles in the spleen, liver, and tumors. The tumor fractional blood volume measurements determined from the two imaging methods were in agreement, and a high correlation (R(2) = 0.81) was found between measured fractional blood volume and histology-derived microvascular density. Vascular permeability measurements obtained from the two imaging methods agreed well with ex vivo measurements. CONCLUSIONS: Dual-energy CT using two types of nanoparticles is equivalent to the single nanoparticle method, but allows for measurement of fractional blood volume and permeability with a single scan. As confirmed by ex vivo methods, CT-derived nanoparticle concentrations are accurate. This method could play an important role in lung tumor characterization by CT.Item Open Access Exosome and Biomimetic Nanoparticle Therapies for Cardiac Regenerative Medicine.(Current stem cell research & therapy, 2020-01) Stine, Sydney J; Popowski, Kristen D; Su, Teng; Cheng, KeExosomes and biomimetic nanoparticles have great potential to develop into a wide-scale therapeutic platform within the regenerative medicine industry. Exosomes, a subgroup of EVs with diameter ranging from 30-100 nm, have recently gained attention as an innovative approach for the treatment of various diseases, including heart disease. Their beneficial factors and regenerative properties can be contrasted with various cell types. Various biomimetic nanoparticles have also emerged as a unique platform in regenerative medicine. Biomimetic nanoparticles are a drug delivery platform, which have the ability to contain both biological and fabricated components to improve therapeutic efficiency and targeting. The novelty of these platforms holds promise for future clinical translation upon further investigation. In order for both exosome therapeutics and biomimetic nanoparticles to translate into large-scale clinical treatment, numerous factors must first be considered and improved. Standardization of different protocols, from exosome isolation to storage conditions, must be optimized to ensure batches are pure. Standardization is also important to ensure no variability in this process across studies, thus making it easier to interpret data across different disease models and treatments. Expansion of clinical trials incorporating both biomimetic nanoparticles and exosomes will require a standardization of fabrication and isolation techniques, as well as stricter regulations to ensure reproducibility across various studies and disease models. This review will summarize current research on exosome therapeutics and the application of biomimetic nanoparticles in cardiac regenerative medicine, as well as applications for exosome expansion and delivery on a large clinical scale.Item Open Access Fate and Transformation of Metal-(Oxide) Nanoparticles in Wastewater Treatment(2014) Barton, Lauren ElizabethThe study and application of materials possessing size dimensions in the nano scale range and, as a result, unique properties have led to the birth of a new field; nanotechnology. Scientists and engineers have discovered and are exploiting the novel physicochemical characteristics of nanoparticles (NPs) to enhance consumer products and technologies in ways superior to their bulk counterparts. Escalating production and use of NPs will unavoidably lead to release and exposure to environmental systems. This introduction of emerging potential contaminant NPs will provide new and interesting challenges for exposure and risk forecasting as well as environmental endurance.
The ultimate goal of this research is to develop a framework that incorporates experimental and computational efforts to assess and better understand the exposure of metal and metal-oxide NPs released to wastewater treatment plants (WWTPs) and further implications on land application units (LAUs) where biosolids can be applied. The foundation of the computational effort is comprised of Monte Carlo mass balance models that account for the unique processes affecting NP fate and transport through the different technical compartments of a WWTP and LAU. Functional assay and bioreactor experiments in environmental media were used to determine parameters capable of describing the critical processes that impact the fate of NPs in wastewater.
The results of this research indicate that a simplified, but still environmentally relevant nano-specific exposure assessment is possible through experimentation to parameterize adapted models. Black box modeling efforts, which have been shown in previous studies, show no disadvantage relative to discretization of technical compartments as long as all key transport and fate mechanisms are considered. The distribution coefficient (_), an experimentally determined, time-dependent parameter, can be used to predict the distribution of NPs between the liquid and solid phase in WWTPs. In addition, this parameter can be utilized a step further for the estimation of the more fundamental, time independent attachment efficiency between the NPs and the solids in wastewater. The NP core, size, and surface coating will influence the value of these parameters in addition to the background particle characteristics as the parameters are specific to the environmental system of study. For the metal and metal-oxide NPs studied, preferential overall association of approximately 90% or greater with the solid phase of wastewater was observed and predicted.
Furthermore, NP transformations including dissolution, redox reactions, and adsorption can potentially impact exposure. For example, experimental results showed that nano-CeO2 is reduced from Ce(IV) to Ce(III) when in contact with wastewater bacteria where Ce2S3 will likely govern the Ce(III) phase in biosolids. From the literature, similar transformations have been observed with Ag and ZnO NPs to Ag2S and ZnS. With respect to TiO2 NPs, studies indicated that due to high insolubility, these NPs would not undergo transformation in WWTPs. The distribution and transformation rate coefficients can then be used in fate models to predict the NP species exposed to aquatic and terrestrial systems and environmentally relevant concentrations released from WWTPs.
Upon completion of the WWTP model, the predicted concentrations of NPs and NP transformation byproducts released in effluent and biosolids were attainable. A simple mass balance model for NP fate in LAUs was then developed to use this output. Results indicate that NP loading on LAUs would be very low but that build up over time to steady state could result in mass concentrations on the order of the typical level for the background metal in soil. Transport processes of plant uptake and leaching were expected to greatly impact the solid phase concentration of the NPs remaining in the LAU, while rainfall did not impart a significant influence upon variation between low and high annual amounts. The significance of this research is the introduction of a method for NP exposure assessment in WWTPs and subsequently in LAUs. This work describes and quantifies the key processes that will impact Ag, TiO2, CeO2 and ZnO NP fate and transport, which can inform future studies, the modeling community and regulatory agencies.
Item Open Access Functional and Molecular Imaging Using Nanoparticle Contrast Agents for Dual-Energy Computed Tomography(2017) Ashton, Jeffrey RonaldX-ray computed tomography (CT) is one of the most useful diagnostic tools for clinicians, with widespread availability, fast scan times, and low cost. CT imaging can reveal a patient’s anatomy in exquisite detail and is extremely useful in the diagnosis of a wide variety of diseases. However, CT is currently limited to anatomical imaging due to the lack of appropriate contrast agents and imaging protocols that would allow for molecular imaging, so clinicians must instead rely on other modalities which are more expensive and less readily available. Dual energy CT, a relatively new technique in which two x-ray energies are used for a single scan, can provide valuable information about tissue material composition. This information can potentially be used for molecular imaging if it is coupled with appropriately-designed contrast agents.
This work aims to extend the use of CT into the molecular imaging realm by developing and testing nanoparticle contrast agents for use with dual energy CT. Several studies were carried out, each of which focused on a different application of using nanoparticle contrast agents together with dual energy CT for molecular imaging.
A commercial blood pool iodine contrast agent for pre-clinical CT (Exia-160) has been shown to accumulate in the myocardium and continue to enhance the myocardium after the contrast agent has been cleared from the bloodstream. It was hypothesized that this agent would not accumulate in infarcted myocardium, which would allow for specific identification of myocardial infarction by CT. Mice were injected with the contrast agent following myocardial infarction, and dual energy CT was used to identify the iodine within the myocardium and separate the iodine from the calcium in the neighboring ribs. Regions of myocardial infarction showed no enhancement on CT, while the healthy myocardium was highly enhanced. Size and position of myocardial infarction determined by dual energy CT were compared with the standard molecular imaging technique for measuring myocardial viability (SPECT). It was found that dual energy CT using this nanoparticle contrast agent reliably agreed with the gold standard molecular imaging method.
Molecular imaging for the improved detection and characterization of lung tumors was also explored through two different studies. The first study used both gold nanoparticles and iodine-containing liposomes together with dual energy CT in order to measure tumor vascular functional parameters, including tumor fractional blood volume and vascular permeability. These dual energy CT measurements were confirmed with ex vivo tissue analysis to demonstrate the validity and accuracy of the in vivo dual energy CT method. The second study used antibody-targeted gold nanoparticles to image EGFR-positive tumors. Two different types of antibodies were tested: a clinically used humanized anti-EGFR antibody, and a small llama-derived single domain anti-EGFR antibody. The single domain antibody showed improved blood half-life and reduced immune clearance compared to the full-sized antibody when attached to gold nanoparticles, but the higher affinity of the full-sized antibody led to much higher overall tumor accumulation. This antibody significantly increased the accumulation of gold nanoparticles in tumors expressing high levels of EGFR. Together, these two studies showed that dual energy CT and nanoparticle contrast agents can be used to measure a wide variety of tumor functional parameters, including tumor vascular density, vascular permeability, and receptor expression. All these parameters can be combined with the anatomical CT imaging to better characterize lung tumors and differentiate between benign and malignant lesions.
The use of dual energy CT for measuring tumor vascular permeability changes after gold nanoparticle-augmented radiation therapy was also demonstrated. Liposomal iodine was injected into mice following radiation therapy in order to measure vascular permeability. Dual energy CT was used to differentiate the signal of the liposomal iodine from the CT signal of the gold nanoparticles already in the tumor. Tumor permeability was measured with CT using multiple combinations of gold nanoparticles and radiation doses to find the optimal conditions for enhancing the effect of radiation therapy on the vasculature. These conditions were then used to increase the delivery of a liposomal chemotherapy agent to tumors. Tumors treated with the gold-augmented radiation therapy and liposomal drug showed significant growth delay compared to the other groups, confirming the predictions made in the dual energy CT imaging.
Finally, a protease-responsive contrast agent was developed for use with dual energy CT imaging. Clusters of gold nanoparticles cross-linked together by protease-sensitive peptides were injected into mice along with liposomal iodine. In the presence of tumor proteases, the clusters degraded and the concentration of gold within the tumor decreased. Clusters without the protease-sensitive peptide did not degrade and did not leave the tumors. The ratio of iodine to gold in each tumor was measured, and it was found that the ratio was significantly higher in mice injected with the degradable gold clusters compared to mice injected with non-degradable control clusters. This demonstrated the ability to use multiple contrast agents with dual energy CT for enzyme-specific ratiometric molecular imaging.
This work confirms that dual energy CT can be used along with multiple nanoparticle contrast agents for molecular imaging applications. With continued contrast agent development and further application of dual energy CT, these methods can potentially be applied clinically to improve the power of CT imaging and improve diagnosis of a wide variety of pathologies.
Item Open Access Gallium-based Ultraviolet Nanoplasmonics(2013) Yang, YangNanometer-scale metallic structures have been widely and intensively studied over the last decade because of their remarkable plasmonic properties that can enhance local electromagnetic (EM) fields. However, most plasmonic applications are restricted to the visible and near infrared photon energies due to the limitations of the surface plasmon resonance energies of the most commonly used plasmonic metals: Au and Ag. Plasmonic applications in ultraviolet (UV) are of great interest because Raman scattering sections are larger and do not overlap fluorescence spectra. UV plasmonics also benefit from high spatial resolution and low penetration depth. However, an appropriate UV plasmonic material must be identified.
We proposed and demonstrated that gallium is a highly-promising and compelling material for UV nanoplasmonics through synthesis of size-controlled nanoparticle arrays, EM modeling of local field enhancement, ellipsometric and spatial characterization of the arrays, and analytical measurement of UV- enhanced Raman and fluorescence spectra. Self-assembled arrays of hemispherical gallium nanoparticles deposited by molecular beam epitaxy on a sapphire support are characterized with spatial and ellipsometric measurements. Spin-casting a thin film of crystal violet upon these nanoparticles permitted the demonstration of surface-enhanced Raman spectra, fluorescence, and molecular photodegradation following excitation by a HeCd laser operating at 325 nm (UV). Measured local Raman enhancement factors exceeding 107 demonstrated the potential of gallium nanoparticle arrays for plasmonically-enhanced ultraviolet detection and remediation.
Item Embargo Hydrogel-Mediated Gene Delivery from Granular Scaffolds for Applications in Biologics Manufacturing and Regenerative Medicine(2023) Kurt, Evan MichaelNucleic acid delivery has applications ranging from tissue engineering to biologics development and manufacturing to vaccines and infectious disease. To improve delivery and extend viable expression over time, we turn to biomaterials as a method for sustained nucleic acid release and enhanced cell culture or tissue interaction. Here, we describe how cationic polymer and lipid condensed nucleic acids can be effectively loaded into injectable granular hydrogel scaffolds by stabilizing the condensed nucleic acid into a lyophilized powder, loading the powder into a bulk hydrogel, and then fragmenting the gel into hydrogel microparticles. The resulting microgels contain non-aggregated nucleic acid particles, can be annealed into an injectable microporous scaffold, and can effectively deliver nucleic acids to cells with a sustained rate of expression. We explore how this technology can improve the production of biologics, like antibodies and viruses, to overcome limitations of current batch processes. Our scaffolds allow for continuous biologics manufacturing, with sustained production upwards of 30 days. We also explore how our platform can improve tissue regeneration in disease models like dermal wounds by delivering nucleic acid drugs, namely DNA, mRNA, and therapeutic viruses. The loaded granular scaffolds allow cells to readily repopulate the missing tissue and drugs be locally released and taken up over time. Overall, our scaffold delivery approach is a customizable platform that can be tuned for many different applications.
Item Open Access Inhibition of the futalosine pathway for menaquinone biosynthesis suppresses Chlamydia trachomatis infection.(FEBS letters, 2021-12) Dudiak, Brianne M; Nguyen, Tri M; Needham, David; Outlaw, Taylor C; McCafferty, Dewey GChlamydia trachomatis, an obligate intracellular bacterium with limited metabolic capabilities, possesses the futalosine pathway for menaquinone biosynthesis. Futalosine pathway enzymes have promise as narrow-spectrum antibiotic targets, but the activity and essentiality of chlamydial menaquinone biosynthesis have yet to be established. In this work, menaquinone-7 (MK-7) was identified as a C. trachomatis-produced quinone through liquid chromatography-tandem mass spectrometry. An immunofluorescence-based assay revealed that treatment of C. trachomatis-infected HeLa cells with the futalosine pathway inhibitor docosahexaenoic acid (DHA) reduced inclusion number, inclusion size, and infectious progeny. Supplementation with MK-7 nanoparticles rescued the effect of DHA on inclusion number, indicating that the futalosine pathway is a target of DHA in this system. These results open the door for menaquinone biosynthesis inhibitors to be pursued in antichlamydial development.Item Open Access Leveraging nanoscale plasmonic modes to achieve reproducible enhancement of light.(Nano Lett, 2010-10-13) Hill, Ryan T; Mock, Jack J; Urzhumov, Yaroslav; Sebba, David S; Oldenburg, Steven J; Chen, Shiuan-Yeh; Lazarides, Anne A; Chilkoti, Ashutosh; Smith, David RThe strongly enhanced and localized optical fields that occur within the gaps between metallic nanostructures can be leveraged for a wide range of functionality in nanophotonic and optical metamaterial applications. Here, we introduce a means of precise control over these nanoscale gaps through the application of a molecular spacer layer that is self-assembled onto a gold film, upon which gold nanoparticles (NPs) are deposited electrostatically. Simulations using a three-dimensional finite element model and measurements from single NPs confirm that the gaps formed by this process, between the NP and the gold film, are highly reproducible transducers of surface-enhanced resonant Raman scattering. With a spacer layer of roughly 1.6 nm, all NPs exhibit a strong Raman signal that decays rapidly as the spacer layer is increased.Item Open Access Long-term transformation and fate of manufactured ag nanoparticles in a simulated large scale freshwater emergent wetland.(Environ Sci Technol, 2012-07-03) Lowry, GV; Espinasse, BP; Badireddy, AR; Richardson, CJ; Reinsch, BC; Bryant, LD; Bone, AJ; Deonarine, A; Chae, S; Therezien, M; Colman, BP; Hsu Kim, H; Bernhardt, ES; Matson, CW; Wiesner, MRTransformations and long-term fate of engineered nanomaterials must be measured in realistic complex natural systems to accurately assess the risks that they may pose. Here, we determine the long-term behavior of poly(vinylpyrrolidone)-coated silver nanoparticles (AgNPs) in freshwater mesocosms simulating an emergent wetland environment. AgNPs were either applied to the water column or to the terrestrial soils. The distribution of silver among water, solids, and biota, and Ag speciation in soils and sediment was determined 18 months after dosing. Most (70 wt %) of the added Ag resided in the soils and sediments, and largely remained in the compartment in which they were dosed. However, some movement between soil and sediment was observed. Movement of AgNPs from terrestrial soils to sediments was more facile than from sediments to soils, suggesting that erosion and runoff is a potential pathway for AgNPs to enter waterways. The AgNPs in terrestrial soils were transformed to Ag(2)S (~52%), whereas AgNPs in the subaquatic sediment were present as Ag(2)S (55%) and Ag-sulfhydryl compounds (27%). Despite significant sulfidation of the AgNPs, a fraction of the added Ag resided in the terrestrial plant biomass (~3 wt % for the terrestrially dosed mesocosm), and relatively high body burdens of Ag (0.5-3.3 μg Ag/g wet weight) were found in mosquito fish and chironomids in both mesocosms. Thus, Ag from the NPs remained bioavailable even after partial sulfidation and when water column total Ag concentrations are low (<0.002 mg/L).Item Open Access Magnetophoretic circuits for digital control of single particles and cells.(Nat Commun, 2014-05-14) Lim, B; Reddy, V; Hu, X; Kim, K; Jadhav, M; Abedini-Nassab, R; Noh, Y; Lim, YT; Yellen, BB; Kim, CThe ability to manipulate small fluid droplets, colloidal particles and single cells with the precision and parallelization of modern-day computer hardware has profound applications for biochemical detection, gene sequencing, chemical synthesis and highly parallel analysis of single cells. Drawing inspiration from general circuit theory and magnetic bubble technology, here we demonstrate a class of integrated circuits for executing sequential and parallel, timed operations on an ensemble of single particles and cells. The integrated circuits are constructed from lithographically defined, overlaid patterns of magnetic film and current lines. The magnetic patterns passively control particles similar to electrical conductors, diodes and capacitors. The current lines actively switch particles between different tracks similar to gated electrical transistors. When combined into arrays and driven by a rotating magnetic field clock, these integrated circuits have general multiplexing properties and enable the precise control of magnetizable objects.