scholarly journals Microneedle Patterning of 3D Nonplanar Surfaces on Implantable Medical Devices Using Soft Lithography

Micromachines ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 705 ◽  
Author(s):  
Jang ◽  
Doshi ◽  
Nerayo ◽  
Caprio ◽  
Alaie ◽  
...  

Micropatterning is often used to engineer the surface properties of objects because it allows the enhancement or modification of specific functionalities without modification of the bulk material properties. Microneedle arrays have been explored in the past for drug delivery and enhancement of tissue anchoring; however, conventional methods are primarily limited to thick, planar substrates. Here, we demonstrate a method for the fabrication of microneedle arrays on thin flexible polyurethane substrates. These thin-film microneedle arrays can be used to fabricate balloons and other inflatable objects. In addition, these thin-filmed microneedles can be transferred, using thermal forming processes, to more complex 3D objects on which it would otherwise be difficult to directly pattern microneedles. This function is especially useful for medical devices, which require effective tissue anchorage but are a challenging target for micropatterning due to their 3D nonplanar shape, large size, and the complexity of the required micropatterns. Ultrathin flexible thermoplastic polyurethane microneedle arrays were fabricated from a polydimethylsiloxane (PDMS) mold. The technique was applied onto the nonplanar surface of rapidly prototyped soft robotic implantable polyurethane devices. We found that a microneedle-patterned surface can increase the anchorage of the device to a tissue by more than twofold. In summary, our soft lithographic patterning method can rapidly and inexpensively generate thin-film microneedle surfaces that can be used to produce balloons or enhance the properties of other 3D objects and devices.

Author(s):  
Jessica Doan ◽  
Peter Phommahaxay ◽  
Sarah Olson ◽  
Matthew A. Petersen

We describe the formulation and manufacture of thermoplastic polyurethane (TPU)-based steroid-eluting components and the development of a versatile, material-agnostic analytical method for their rapid characterization. The impact of materials, formulation, and processing on controlled release behavior was characterized and compared to current industry standard components under physiologically relevant conditions. The combination of factors modulated drug release, offering new avenues for controlling the release of steroids from implantable medical devices.


1999 ◽  
Vol 581 ◽  
Author(s):  
Brent A. Ridley ◽  
Babak Nivi ◽  
Brian N. Hubert ◽  
Colin A. Bulthaup ◽  
Eric J. Wilhelm ◽  
...  

ABSTRACTPyridine solutions of CdSe nanocrystals were solution-deposited in the fabrication of thin film transistors (TFTs). A peak mobility of 1 cm2V−1s−1 and an ON/OFF ratio of 3×104 were observed for TFTs processed at 350 °C. The nanocrystals acted as a precursor to the bulk material, coalescing to form a semiconductor thin film when heated at plastic-compatible temperatures. Single crystalline regions several hundred times the size of the original semiconductor nanocrystals were observed for films processed at 350 °C. We also report a process for direct liquid phase deposition and patterning of nanoparticle inks at sub-micron resolutions by elastomeric embossing and AFM nanospotting. These results suggest that microelectronic devices produced from nanoparticle-based inks can enjoy the processing advantages usually associated with organic materials while retaining the performance advantages typically associated with inorganic materials.


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