AVS 65th International Symposium & Exhibition
    Biomaterial Interfaces Division Tuesday Sessions
       Session BI+AS+IPF+NS-TuA

Paper BI+AS+IPF+NS-TuA1
Functionalization of Silica Materials via Click Reaction of Surface Silanol Groups with Vinyl Sulfones

Tuesday, October 23, 2018, 2:20 pm, Room 101B

Session: IoT Session: Biofabrication, Bioanalytics, Biosensors and Diagnostics and Flash Networking Session
Presenter: Fang Cheng, Dalian University of Technology, China
Authors: F. Cheng, Dalian University of Technology, China
H. Wang, Dalian University of Technology, China
W. He, Dalian University of Technology, China
B. Sun, Dalian University of Technology, China
J. Qu, Dalian University of Technology, China
Correspondent: Click to Email
Silica-based materials are widely used in the fields of catalysis, chromatography, biomaterials, biosensing and drug delivery due to their earth abundance and low cost. Success of these applications mostly relies on the functionalization of silica surfaces, among which covalent binding of organic molecules is preferred. Common strategies for the covalent functionalization of silica materials involve either silane treatments or Si-H reactions. Each has its share of limitations, with the former suffering from self-polymerization and multilayer modifications, and the latter being sensitive to moisture and oxygen. Herein, we proposed the ‘click’ reaction of silanol groups with vinyl sulfones, which enables a new and simple strategy for functionalization of silica materials. For the first time, the ‘click’ concept was extended to silanol groups that are abundant on the surface of silica materials, using compounds bearing vinyl sulfone groups. By simply immersing silica materials in vinyl sulfone solutions at 60℃, functionalization could be achieved in hours in the presence of catalysts. The chemical stability of vinyl sulfones and mild reaction conditions make this strategy advantageous than silane treatments and Si-H reactions. We demonstrated that silica materials with sizes ranging from microscale to macroscale could all be functionalized. Using compounds bearing multiple vinyl sulfone groups, silica materials can be further functionalized with varies of biomolecules due to the versatile reactivity of vinyl sulfone group towards thiol, amino and alcohols. Furthermore, the stability of resulting Si-O-C bond can be tuned by the properties of the vinyl sulfone compounds (e.g., hydrophobicity and surface density) as well as the environmental factors (e.g., solvents, pH and temperature). Increase in the hydrophobicity and functionalization density of the vinyl sulfone compounds could increase the stability of Si-O-C bonds. Contrast to the high stability in organic solvents, degradation of Si-O-C bond can be realized in aqueous solutions, which can be accelerated by addition of acid or base. This is rarely observed with bonds produced based of silane treatments and Si-H reactions. It could broaden the biomedical applications of functionalized silica, for example, to provide tailored release of drugs or proteins from silica surface.