Exploring the use of native spider silk as an optical fibre for chemical sensing

A spider uses up to seven different types of silk, all having specific functions, as building material, weapon and sensory organ to detect the presence of preys on its web. Recently, scientists have put under the limelight the extraordinary properties of this ancient material. Indeed, native silk, directly extracted from spiders, is a tough, biodegradable and biocompatible thread used mainly for tissue engineering and textile applications. Blessed with outstanding optical properties, this protein strand can also be used as a bioresorbable optical fibre and is, moreover, intrinsically sensitive to chemical compounds. In this communication, the waveguiding properties of native dragline silk are assessed and a pioneering proof-of-concept experiment using pristine spider silk as an optical fibre to measure humidity content is demonstrated. The feasibility of using silk-based optical fibre chemical sensors is also discussed.

Weaving our way towards a new generation of ﬁbre-optic chemical sensors based on spider silk

Desmond Chow Ming Chia, Isabelle Dicaire, Kenny Hey Tow, Luc Thévenaz

From the spider’s perspective, silk is not only a building material but also a safety net, a weapon and a sensory organ to detect the presence of preys on its web. Indeed, this primeval material has been shaped over hundreds of millions of years by spiders to create a myriad of silk ﬁbre types with different level of toughness, elasticity, stickiness depending on its attributed function in the web. From a human perspective, scientists are currently working on harnessing all the extraordinary properties of this material for applications spiders would never thought of, from biocompatible tissue engineering (enhancement of skin regeneration and nerve guides) to biodegradable electronics and development of specialised textile and composites. However, the potential of using spider silk ﬁbre for chemical sensing has been overlooked. In this communication, we will explore the potential of using spider silk as a new type of ﬁbre optic chemical sensor in a fully bio-inspired approach.

Ieee2016

Towards a new generation of fibre-optic chemical sensors based on spider silk threads

Desmond Chow Ming Chia, Isabelle Dicaire, Kenny Hey Tow, Luc Thévenaz

A spider uses up to seven different types of silk, all having specific functions, to build its web. For scientists, native silk - directly extracted from spiders - is a tough, biodegradable and biocompatible thread used mainly for tissue engineering and textile applications. Blessed with outstanding optical properties, this protein strand can also be used as an optical fibre and is, moreover, intrinsically sensitive to chemical compounds. In this communication, a pioneering proof-of-concept experiment using spider silk, in its pristine condition, as a new type of fibre-optic relative humidity sensor will be demonstrated and its potential for future applications discussed.

Ieee2016

Functionalization of polymer optical fibers for medical application

Jialuo Luo

The increasing challenges caused by the growing and aging population and the fast pace of life are calling for a change of our current medical care system towards being rapid, easy, and on-demand self-care. Empowerment with the self-caring components such as early diagnosis, treatment, and monitoring of individuals will sharply release the social burden. In this context, fibrous materials stand out for their small size, processing flexibility, designable functionalities, and the possibility to be further integrated into im-plants or wearable devices. As we know, optical fiber is widely used in the biomedical field. For example, conventional silica optical fiber has mature applications such as light guides for surgery and catheter-based endoscopy while novel types of optical fiber (hydrogel, polymer, biomedical material, and elastomer) open the door to various new application scenarios like optogenetics, active monitoring, and continuous sensing, etc. While it remains a hot topic, the use of optical fibers for drug delivery is still in lack of exploration and suggests an ideal starting point for us. Optical fiber allows light propagation and thus gives the possibility to build up a light-responsive delivery system if combined with light-responsive drug carriers. Mesoporous silica nanoparticles(MSNP) were selected to host drug substances due to their high surface area, big pore volume, and versatility of functionalization and were coated on the fiber. Optical fiber will work as a light source to trigger the release from carriers. In this thesis, we constructed the hybrid system to give an optical fiber-based release system and elucidate the interaction between light from the optical fiber and drug-hosted particles with a further expectation to integrate with sensing or monitor-ing function to have an advanced delivery device. The first part of the work involved the synthesis of mesoporous silica nanoparticles using non-surfactants as templating agents. For the first time, a systematic study has been carried out to unravel the morphogenetic mechanism of mesoporous silica nanoparticles by polyphenols. Our study has, on one side, suggested that the pKa value of the polyphenols is responsible for the particle size due to the effect on nucleation and particle growth process, and on the other side, demonstrated that the formation of the supramolecular network contributes to the porous structure by serving as the skeleton for the silica pre-cursors to polymerize around. The second part of the work is to establish a method to generate a particle-polymer optical fiber(POF) complex matrix. A robust and controlled strategy for the fabrication of particle-coated surfaces that applies to multiple genres of substrates and coating materials was proposed based on layer-by-layer(LbL) assembly. The approach enables a high drug loading as well as a low structural complexity en-dowed by a dense and homogenous monolayer coverage of particles on the substrates. The computer vision method was employed to quantitatively evaluate the particle coating, increasing dramatically the efficiency and accuracy of the coating evaluation. The final part of the work investigates the light-responsive release of photolabile coumarin-chlorambucil conjugates from optical fibers. To the best of our knowledge, it is the first study to explore the release of drugs from the side of optical fibers. Overall, this novel particle-optical fiber-based one-dimensional drug deliver

EPFL2022

Functionalization of polymer optical fibers for medical application

Jialuo Luo

EPFL2022