Porous silica supports for micro-Raman spectroscopic studies of individual living cells

A work was undertaken to explore the possibility of using porous silica gels as support materials for in vitro studies of individual living cells. Accordingly, tetra methyl orthosilicate-derived silica xerogels were prepared and tested as substrates for human breast adenocarcinoma MCF-7 cells. Micro-Raman spectra and BET measurements were used to determine the effect of sol-pH and autoclave sterilization on the substrate. MCF-7 cells were then seeded and grown on the resulting silica gels. Combined techniques show that (a) sol-pH affects substrate porosity and (b) autoclave conditions affect only the substrate surface thus increasing the surface porosity. Micro-Raman spectra of in situ grown MCF-7 cells indicate that they proliferate well on these xerogel surfaces with a preference for base-catalyzed substrates and that the surface morphology of supports can have a definite effect on the adherence and on the life time of human cells. Spectral evolutions observed for cells over a period of 48 h have made it possible to show that these substrates enable the easy maintenance of cell viability for over 36 h and that micro-Raman techniques make it possible to study individual cells and to characterize evolutional changes at different stages of their life-times. Results point to these new porous silica supports as promising substrates for rapid screening of drug toxicity.