Multifunctional Mesopores for Wound Dressing with Integrated Recognition, and Release Functions

The goal was to develop a multifunctional wound dressing that is able to sense infection and release an infection-treating drug with a defined concentration-time (C-t) profile. This goal was motivated by the vision to treat bacterial infections in situations in which wound dressing change is difficult such as burns, to treat infections with resistant bacteria using antimicrobial peptide (AMP) as an alternative to existing antibiotics. Mesoporous silica materials were synthesized using sol-gel chemistry and functionalized with the photocleavable linker BODIPY, enabling AMP conjugation and on-demand release of therapeutic cargo. These multifunctional materials provided precise control over release kinetics and spatial distribution, key design factors for peptide-based nanomaterials. Two complementary strategies were investigated for peptide conjugation: direct synthesis of ultra-short peptides within silica nanopores and surface grafting of pre-synthesized peptides. In the first approach, peptides were synthesized directly within nanopores, allowing systematic analysis of the effects of peptide sequence and pH on ionic transport. Cyclic voltammetry and ellipsometry revealed that peptide sequence design could effectively regulate molecular transport through nanoscale pores, providing control of diffusion and accessibility. In the second strategy, AMPs such as C14R and melittin were grafted onto mesoporous silica films and particles. Characterization techniques, including ATR-FTIR spectroscopy, thermogravimetric analysis, and confocal laser microscopy, confirmed successful peptide functionalization. Photolysis of the BODIPY linker enabled light-triggered AMP release with precisely tuned release profiles, achieving significant bacterial reduction in Escherichia coli (E. coli) cultures. In collaboration with Prof. Petra J. Cameron and Dr. Celine Feuilloley, mesoporous silica was incorporated into hydrogels which were capable of detecting the presence of bacteria. The hydrogel consists of gelatin crosslinked with genipin and C14R peptide-functionalized particles that further extend functionality to bacterial sensing and release AMPs for treatment. In the presence of bacteria, these hydrogels degraded with proteases that were produced by bacteria. These hydrogel-silica hybrid materials demonstrated antimicrobial efficacy, reducing bacterial colony counts in culture tests under irradiation. To assess commercial feasibility, the materials were incorporated into traditional wound dressing substrates, including paper and woven fabrics, which retained bacterial sensing capabilities and achieved almost complete suppression of bacterial growth under green light irradiation. This thesis highlights the versatility of mesoporous silica-based materials as a platform for advanced wound care solutions. Future research should prioritize in vivo validation and expanded testing across diverse bacterial strains to establish their clinical relevance.