Application of Fluorescence Techniques to Characterise the Preparation of Protein-Containing Sol-Gel Derived Hosts for use as Catalytic Media

Abstract

In this work we collate and review the usage that we have made of fluorescence techniques employed to follow the sol to gel transition and aging in different tetraethylorthosilicate based materials. The sol-gel method allows porous glasslike of good optical quality to be produced at relatively low (ambient) temperatures, which facilitates the incorporation of a range of molecules; from laser dyes to biomolecules. Here the use of “common” viscosity (DASPMI) and polarity (Nile red) sensitive fluorescence probes to monitor the host manufacture is made. Nile red was also used to label two catalytically active proteins (cytochrome c and subtilisin Carlsberg). These were incorporated into the different host media and the dye used to ascertain changes in protein conformation, both upon incorporation and at the end of an aging period. Complementary measurements of catalytic activity were performed. The probe emission was monitored via steady state and time-resolved fluorescence techniques and comparison made with the catalytic activity measurements to elucidate the amount of accessible and active protein. Overall it was found that the hosts became stable after an aging period approaching 20 days and that the major influence on the catalytic reaction rates was that of host mediated mass transport.

In situ formation of silver nanostructures produced via laser irradiation within sol–gel derived films and their interaction with a fluorescence tagged protein

“…7 There have been reports of the use of laser irradiation to perform the reduction of silver in a zeolite 19 and silver oxide has been shown to undergo changes (both in oxidation state and clustering) upon photoactivation. 20 Materials produced using the sol-gel technique 21,22 have been previously used by one of the authors to incorporate bioactive molecules (proteins/enzymes that can exhibit catalytic activity) [23][24][25] and the matrix forming reaction can be readily adapted to include the presence of silver ions within silica films. Media can be produced using this technique at room temperature or lower and exhibit robust glass-like properties, are highly porous and have large internal surface areas.…”

Time-resolved fluorescence microscopy to study biologically related applications using sol-gel derived and cellular media

“…Materials produced using the sol-gel technique 12,13 have been previously used by one of the authors to incorporate bioactive molecules (proteins / enzymes that can exhibit catalytic activity) [14][15][16] and the matrix forming reaction can be readily adapted to include the presence of silver ions within silica films. Media can be produced using this technique at room temperature or lower and exhibit robust glass-like properties and are highly porous and have large internal surface areas.…”

Effect of sol maturation on the preparation of luminescent ormosils

“…The family of organotrialkoxysilanes RSi(OR′) 3 represents a class of versatile building blocks toward designing silicon‐based hybrid organic–inorganic materials (termed “ormosils”) . They afford in situ incorporation of a broad range of organic materials (e.g., fluorescence dyes or surface active agent), biomaterials (e.g., enzyme or cells), and inorganic dopants (i.e., lanthanide elements) into matrix (i.e., glasses, gels) via sol–gel process . This ability allows us to tailor host–guest interactions, critical for a variety of applications including biomedical and chemical sensors, biological embedding and conservation materials, porous supports and catalysts, antiscratch coatings, and optical devices …”