Browsing by Subject "Printing, Three-Dimensional"

Now showing 1 - 4 of 4
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    3D-Printed Microneedles Create Precise Perforations in Human Round Window Membrane in Situ.
    (Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology, 2020-02) Chiang, Harry; Yu, Michelle; Aksit, Aykut; Wang, Wenbin; Stern-Shavit, Sagit; Kysar, Jeffrey W; Lalwani, Anil K

    Hypothesis

    Three-dimensional (3D)-printed microneedles can create precise holes on the scale of micrometers in the human round window membrane (HRWM).

    Background

    An intact round window membrane is a barrier to delivery of therapeutic and diagnostic agents into the inner ear. Microperforation of the guinea pig round window membrane has been shown to overcome this barrier by enhancing diffusion 35-fold. In humans, the challenge is to design a microneedle that can precisely perforate the thicker HRWM without damage.

    Methods

    Based on the thickness and mechanical properties of the HRWM, two microneedle designs were 3D-printed to perforate the HRWM from fresh frozen temporal bones in situ (n = 18 total perforations), simultaneously measuring force and displacement. Perforations were analyzed using confocal microscopy; microneedles were examined for deformity using scanning electron microscopy.

    Results

    HRWM thickness was determined to be 60.1 ± 14.6 (SD) μm. Microneedles separated the collagen fibers and created slit-shaped perforations with the major axis equal to the microneedle shaft diameter. Microneedles needed to be displaced only minimally after making initial contact with the RWM to create a complete perforation, thus avoiding damage to intracochlear structures. The microneedles were durable and intact after use.

    Conclusion

    3D-printed microneedles can create precise perforations in the HRWM without damaging intracochlear structures. As such, they have many potential applications ranging from aspiration of cochlear fluids using a lumenized needle for diagnosis and creating portals for therapeutic delivery into the inner ear.
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    Characterizing the Switching Thresholds of Magnetophoretic Transistors.
    (Adv Mater, 2015-10-28) Abedini-Nassab, Roozbeh; Joh, Daniel Y; Van Heest, Melissa A; Yi, John S; Baker, Cody; Taherifard, Zohreh; Margolis, David M; Garcia, J Victor; Chilkoti, Ashutosh; Murdoch, David M; Yellen, Benjamin B
    The switching thresholds of magnetophoretic transistors for sorting cells in microfluidic environments are characterized. The transistor operating conditions require short 20-30 mA pulses of electrical current. By demonstrating both attractive and repulsive transistor modes, a single transistor architecture is used to implement the full write cycle for importing and exporting single cells in specified array sites.
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    Effect of surface topography on in vitro osteoblast function and mechanical performance of 3D printed titanium.
    (Journal of biomedical materials research. Part A, 2021-10) Abar, Bijan; Kelly, Cambre; Pham, Anh; Allen, Nicholas; Barber, Helena; Kelly, Alexander; Mirando, Anthony J; Hilton, Matthew J; Gall, Ken; Adams, Samuel B
    Critical-sized defects remain a significant challenge in orthopaedics. 3D printed scaffolds are a promising treatment but are still limited due to inconsistent osseous integration. The goal of the study is to understand how changing the surface roughness of 3D printed titanium either by surface treatment or artificially printing rough topography impacts the mechanical and biological properties of 3D printed titanium. Titanium tensile samples and discs were printed via laser powder bed fusion. Roughness was manipulated by post-processing printed samples or by directly printing rough features. Experimental groups in order of increasing surface roughness were Polished, Blasted, As Built, Sprouts, and Rough Sprouts. Tensile behavior of samples showed reduced strength with increasing surface roughness. MC3T3 pre-osteoblasts were seeded on discs and analyzed for cellular proliferation, differentiation, and matrix deposition at 0, 2, and 4 weeks. Printing roughness diminished mechanical properties such as tensile strength and ductility without clear benefit to cell growth. Roughness features were printed on mesoscale, unlike samples in literature in which roughness on microscale demonstrated an increase in cell activity. The data suggest that printing artificial roughness on titanium scaffold is not an effective strategy to promote osseous integration.
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    Innovations With 3-Dimensional Printing in Physical Medicine and Rehabilitation: A Review of the Literature.
    (PM & R : the journal of injury, function, and rehabilitation, 2016-12) Lunsford, Christopher; Grindle, Garrett; Salatin, Benjamin; Dicianno, Brad E
    Created more than 30 years ago, 3-dimensional printing (3DP) has recently seen a meteoric rise in interest within medicine, and the field of Physical Medicine and Rehabilitation is no exception. Also called additive manufacturing (AM), the recent increase in the use of 3DP is likely due to lower-cost printers as well as breakthroughs in techniques and processing. This thematic narrative review serves to introduce the rehabilitation professional to 3DP technology and how it is being applied to orthoses, prostheses, and assistive technology (AT). The basics of the technology, as well as the benefits and challenges of using it within the rehabilitation framework, are described. Proponents of the technology suggest that 3DP offers not only a better way to make devices, but a better way to make improved devices. However, the strength of this claim has not been properly tested by the current literature. This narrative review evaluates the evidence and provides a discussion of possible implications for the rehabilitation professional.