Browsing by Subject "Silica"
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Item Open Access Biologically Inspired Design of Protein-Silica Hybrid Nanoparticles for Drug Delivery Applications(2016) Han, WeiThe design and application of effective drug carriers is a fundamental concern in the delivery of therapeutics for the treatment of cancer and other vexing health problems. Traditionally utilized chemotherapeutics are limited in efficacy due to poor bioavailability as a result of their size and solubility as well as significant deleterious effects to healthy tissue through their inability to preferentially target pathological cells and tissues, especially in treatment of cancer. Thus, a major effort in the development of nanoscopic drug delivery vehicles for cancer treatment has focused on exploiting the inherent differences in tumor physiology and limiting the exposure of drugs to non-tumorous tissue, which is commonly achieved by encapsulation of chemotherapeutics within macromolecular or supramolecular carriers that incorporate targeting ligands and that enable controlled release. The overall aim of this work is to engineer a hybrid nanomaterial system comprised of protein and silica and to characterize its potential as an encapsulating drug carrier. The synthesis of silica, an attractive nanomaterial component because it is both biocompatible as well as structurally and chemically stable, within this system is catalyzed by self-assembled elastin-like polypeptide (ELP) micelles that incorporate of a class of biologically-inspired, silica-promoting peptides, silaffins. Furthermore, this methodology produces near-monodisperse, hybrid inorganic/micellar materials under mild reaction conditions such as temperature, pH and solvent. This work studies this material system along three avenues: 1) proof-of-concept silicification (i.e. the formation and deposition of silica upon organic materials) of ELP micellar templates, 2) encapsulation and pH-triggered release of small, hydrophobic chemotherapeutics, and 3) selective silicification of templates to potentiate retention of peptide targeting ability.
Item Embargo Knowledge, Attitudes, and Practices Regarding Respirable Silica Exposure and Personal Protective Equipment Use among Brick Kiln Workers in Nepal(2024) Gaviola, Chelsea VillanuevaBackground: Brick kiln workers in Nepal are a neglected population who are exposed to high concentrations of respirable silica. We aimed to characterize the prevalence of respiratory personal protective equipment (PPE) use, understand knowledge and attitudes towards kiln dust and respiratory PPE, and identify factors associated with current respiratory PPE use among brick kiln workers in Nepal. Methods: We conducted a cross-sectional study in Bhaktapur, Nepal. We used simple random selection to identify 10 out of 64 total kilns and stratified random sampling to enroll workers aged ≥14 years and household members aged ≥9 years within selected kilns. Field workers surveyed participants using structured questionnaires. Our primary outcome was to characterize prevalence of current respiratory PPE use, and secondary outcomes were summaries of knowledge, attitudes, and practice of PPE use. Results: We surveyed 83 workers (mean age 30.8 years, 77.1% male). Of these, 28.9% reported current respiratory PPE use at work. 3.6% of workers heard of silicosis prior to the survey and 24.1% correctly identified the best respiratory PPE for reducing dust exposure. Respiratory PPE users had higher income (non-brick kiln season mean monthly household income USD 206 vs. 145) and education levels (25% vs. 5.1% completed more than primary school) compared to non-users. Conclusions: Prevalence of respiratory PPE use was low. Workers had poor knowledge of kiln dust health effects and proper respiratory PPE. We highlight important barriers to PPE use, particularly knowledge gaps, which can guide future investigations to reduce silicosis burden among brick kiln workers.