Three-Dimensionally-Patterned Submicrometer-Scale Hydrogel/Air Networks That Offer a New Platform for Biomedical Applications

Abstract

Phase mask interference lithography was employed to fabricate three-dimensional (3D) hydrogel structures with high surface area on neural prosthetic devices. A random terpolymer of poly(hydroxyethyl methacrylate-ran-methyl methacrylate-ran-methacrylic acid) was synthesized and used as a negative-tone photoresist to generate bicontinuous 3D hydrogel structures at the submicrometer scale. We demonstrated that the fully open 3D hydrogel/air networks can be used as a pH-responsive polymeric drug-release system for the delivery of neurotrophins to enhance the performance of neural prosthetic devices. Additionally an open hydrogel structure will provide direct access of neuronal growth to the device for improved electrical coupling.

Three-Dimensional Graphene Nano-Networks with High Quality and Mass Production Capability via Precursor-Assisted Chemical Vapor Deposition

“…Three-dimensional (3D) bi-continuous structures with controlled symmetry and periodicity have found use in many applications in photonic crystals, phononic crystals and micro-electromechanical systems12. In addition, the large surface area and the availability of 3-dimensional responses to external stimuli provide further potential for using 3D structures in diverse areas of energy-related materials and tissue engineering34.…”

Fabrication of 3D high index photonic crystals by holographic lithography and their fidelity

“…However, SU-8 templates often suffer from large volumetric shrinkage (~40% for either diamond-like [11] or simple cubic 3D structures [4]) after PEB and development. While positive-tone photoresists generally have low or no shrinkage [29,30], and can be easily removed by organic solvents, they are not widely used for photonic crystal fabrication due to the limitation of the film thickness (typically less than 5 µm) and absorption in the UV-vis region [31]. Therefore, low-shrinkage negative-tone resist with low-shrinkage, such as glycidyl methacrylate (GMA) resins, are particularly attractive [28].…”

Multi-Beam Interference Advances and Applications: Nano-Electronics, Photonic Crystals, Metamaterials, Subwavelength Structures, Optical Trapping, and Biomedical Structures

“…In some cases, the motif geometry plays a significant role in the performance characteristics of a device fabricated using MBI. For example, the lattice point geometry has been shown to affect the photonic-bandgap characteristics in photonic crystals [30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45], selective plasmonic excitation in plasmonic crystals [46], photonic crystal laser beam pattern [47] and polarization mode control [48], birefringence of photonic crystal fibers [49], cell behavior in tissue engineering [50], tuning of surface textures [51], magnetization switching in periodic magnetic arrays [52], and, negative refraction and superlensing in metamaterials [53,54]. Accordingly, several studies report analytical and computational methods to select individual beam parameters to change the motif orientation and shape [34,42,55,56] from hemispherical to hemielliptical [57]; circular to triangular [58]; as well as, general structures including micro-cavities, micro-bumps, and rectangular bumps [51].…”

“…A wide array of photosensitive materials have been used to record the interference patterns formed by MBIL and include positive resists [115,157,184], negative resists [99,185], hybrid organic-inorganic materials [165,186,187], extreme-UV photoresists [188], silsesquioxane-based photoresists [129], 20 μm holographic polymer-dispersed liquid crystals [189], amorphous-chalcogenide-semiconductor thin films [190], titanium-containing monomer films [191], red-sensitive photopolymers [145], polyimide foils [51], biocompatible polymers [50], oligomer films [153], and even silica [192] and chalcogenide [193] glasses. In the most general terms, given sufficient optical intensity, an interference pattern may be recorded in or on any material that responds to laser illumination at a given wavelength [160], to include direct writing on metallic surfaces via laser interference metallurgy [194] and direct laser interference patterning of -conjugated polymers [195].…”

“…In the development of neural prosthetic devices, phase mask interference lithography was used to fabricate 3D hydrogels with controlled geometries and sub-micron feature sizes as depicted in Figure 15(c). This application could lead to advances in drug delivery, tissue engineering and improved material-device interactions [50]. In the field of antibacterial research, MBIL was used to create a 2D pore-array to immobilize silver nanoparticles, known for their antibacterial properties.…”