Two-photon polymerization nanolithography technology for fabrication of stimulus-responsive micro/nano-structures for biomedical applications

Abstract

Micro/nano-fabrication technology via two-photon polymerization (TPP) nanolithography is a powerful and useful manufacturing tool that is capable of generating two dimensional (2D) to three dimensional (3D) arbitrary micro/nano-structures of various materials with a high spatial resolution. This technology has received tremendous interest in cell and tissue engineering and medical microdevices because of its remarkable fabrication capability for sophisticated structures from macro- to nano-scale, which are difficult to be achieved by traditional methods with limited microarchitecture controllability. To fabricate precisely designed 3D micro/nano-structures for biomedical applications via TPP nanolithography, the use of photoinitiators (PIs) and photoresists needs to be considered comprehensively and systematically. In this review, widely used commercially available PIs are first discussed, followed by elucidating synthesis strategies of water-soluble initiators for biomedical applications. In addition to the conventional photoresists, the distinctive properties of customized stimulus-responsive photoresists are discussed. Finally, current limitations and challenges in the material and fabrication aspects and an outlook for future prospects of TPP for biomedical applications based on different biocompatible photosensitive composites are discussed comprehensively. In all, this review provides a basic understanding of TPP technology and important roles of PIs and photoresists for fabricating high-precision stimulus-responsive micro/nano-structures for a wide range of biomedical applications.

Additive Manufacture of Small-Scale Metamaterial Structures for Acoustic and Ultrasonic Applications

“…MPP in prior studies has repeatedly demonstrated nanoscale print size, suc the aforementioned vat polymerization methods significantly in ultra-high re [124,125]. An example of this is a synthetic nanoporous geomaterial fabricated wi as illustrated in Figure 22, which shows an electron microscope image of a 150 μ of replica shale rock with a minimum feature size of 160 nm [15].…”

Two-Photon Polymerization: Functionalized Microstructures, Micro-Resonators, and Bio-Scaffolds

“…Still, regarding the employed samples in the TPP experiments, photoinitiator compounds are essential to the technique. Many groups have been working on the development or testing of new photoinitiators for TPP experiments [ 72 , 73 ]. Usually, they look for compounds with a high value of TPA cross-section ( ).…”

Multiphoton Laser Fabrication of Hybrid Photo-Activable Biomaterials

“…There are, therefore, plenty of possibilities to develop biomimetic responsive microstructures. The literature is vast: we will provide only recent examples on 3D photo-polymerized hydrogels, leaving more exhaustive analysis to previous reviews [ 133 , 134 , 135 ].…”