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

Abstract

The direct laser writing technique based on two-photon polymerization (TPP) has evolved considerably over the past two decades. Its remarkable characteristics, such as 3D capability, sub-diffraction resolution, material flexibility, and gentle processing conditions, have made it suitable for several applications in photonics and biosciences. In this review, we present an overview of the progress of TPP towards the fabrication of functionalized microstructures, whispering gallery mode (WGM) microresonators, and microenvironments for culturing microorganisms. We also describe the key physical-chemical fundamentals underlying the technique, the typical experimental setups, and the different materials employed for TPP.

Materials and methods for droplet microfluidic device fabrication

“…Much higher resolutions are possible using more advanced systems (e.g. two-photon polymerisation [34][35][36] can give resolutions in the order of 100 nm).…”

“…Various thermoplastics and elastomers can also be 3D printed, but typically at lower resolutions. While high end two photon polymerisation printers can give resolutions in the order of 100 nm, [34][35][36] most commercially available printing methods (fused deposition modelling, stereolithographic addition) produce channels 100 μm or larger. 31 When considering how material choice impacts on droplet microfluidic devices in particular it is useful to examine what materials have been historically used.…”

From Light to Structure: Photo Initiators for Radical Two‐Photon Polymerization

“…[11][12][13] The principle of 2PP is based on the fact that a photo initiator in a monomer solution is excited within the focal point of the laser and, thus, initiates polymerization locally within the focal point. While there have been many reviews reporting on the materials produced via 2PP and their applications, [14][15][16][17][18][19][20][21][22][23] to the best of our knowledge no review has been published yet that addresses the design and efficiencies of the photo initiators. In this review, we will focus on the structural properties, the resulting values, and efficiencies of type I and type II photo initiators for radical 2PP.…”

Assessing the Viscoelasticity of Photopolymer Nanowires Using a Three-Parameter Solid Model for Bending Recovery Motion

“…Two-photon polymerization direct laser writing (TPP-DLW) is one of the basic microstructure fabrication techniques used in biomedical and microfluidic applications [1][2][3][4][5]. TPP-DLW is the best choice for producing microstructures of arbitrary shape with spatial resolution on the order of 100 nm and below [6,7].…”