Trifluorosilane induced structural transitions in beta-lactoglobulin in sol and gel

Fluoroalcohols such as 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) are strong inducers of protein secondary structure. Here, hydrolyzed (3,3,3-trifluoropropyl)trimethoxysilane (3F) is demonstrated to exhibit greater protein conformation inducing activity than HFIP, which is preserved when 3F is copolymerized in tetraethylorthosilicate (TEOS) sol–gels through protein molecular imprinting. Hydrolyzed 3F formed a pre-polymerization complex with the template protein, β-lactoglobulin, inducing distinct α-helical structures as evidenced by circular dichroism. Fluorescence resonance energy transfer between tryptophan and the lipophilic probe 1-anilinonaphthalene-8-sulfonic acid showed a sharp molten globule (MG) transition at 0.2 M 3F, whereas HFIP induced a broad MG transition centered at 0.6 M HFIP. The 3F-induced BLG conformation transitions were retained upon gelation, validating use of the fluorosilane as a conformation directing functional monomer readily incorporated into sol–gels.