Some hints on the use of light-responsive architectures in optics
Polytechnic University of Turin
Department of Applied Science and Technology
A plethora of material processing methods and technologies have been developed in the last decades, thus enabling a rapid progress in important fields such as electronics, optics, biotechnology, micromechanics, and microfluidics. Although miniaturized devices such as MEMS and MOEMS have been widely demonstrated to provide a mechanical actuation upon electrical triggers, most of the micro/nano-structures available at present (irrespective from being bottom-up or top-down fabricated) are static in nature, i.e. their morphology cannot be reversibly modified once manufactured.
In order to overcome this limitation, smart materials based on polymers have been proposed, which are able to change some of their macroscopic properties in response to external stimuli. For example, some polymeric compounds can be made mechanically responsive to light excitation, when doped with light-sensitive molecules such as azobenzene. This feature is particularly interesting, as light constitutes an external stimulus that can be remotely provided in many fashions, e.g. at different wavelengths, polarization states and spatial distributions, without the need of direct wire connections on the target device.
In this talk, I will explore some opportunities of using light-responsive architectures in optics-related applications, with particular regard to the biological domain. Several strategies will be presented, aiming at advancing the synthesis and fabrication technology for 2D/3D patterning of functional light-responsive polymers in the form of biocompatible resins, hydrogels and elastomers exhibiting reversible mechanical variations (e.g. in morphology, mass density, Young modulus, stress) when properly irradiated. In particular, I will focus on the concept of light-responsive smart substrate for living cell cultures.
It is well known that the micro-environment of cells is one of the most important factors that determine what their behavior is: whether they live or die, and even what type of cell they become as they differentiate through their life depending on their interactions with their immediate surroundings. Static 2D and 3D artificial substrates cannot recapitulate the complex spatio-temporal dynamics of a real environment. In an attempt to fill this gap, the concept of an operative platform for implementing a light-driven, real-time control of cell populations growing on light-responsive substrates will be presented. These substrates represent the first illustrative examples of smart scaffolds able to change their mechanical/morphological properties upon proper luminous stimuli. Experimental results on real tumoral cell lines will be anticipated.
The main impact of this interdisciplinary research that combines optics, fabrication technology and polymer science is expected in organoid technology, tissue engineering, regenerative medicine and nerve reparation as well as in many other non-bio domains such as active photonics, security, and energy harvesting.
Emiliano Descrovi is associate professor in Physics at the Department of Applied Science and Technology (DISAT), Politecnico di Torino, Italy and is presently operating in the field of optics and biophotonics, especially in molecular biosensing, quantitative phase imaging and interaction of living matter with light.