Functionalization of polymer optical fibers for medical application

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