Skip to main content Accessibility help

Functionalized Porous Silicon in a Simulated Gastrointestinal Tract: Modeling the Biocompatibility of a Monolayer Protected Nanostructured Material

  • Daniel S. Albrecht (a1), Jacob T. Lee (a2), Nick Molby (a2), Steven D. Rhodes (a2), Hieu Minh Dam (a2), Jason L. Siegel (a2) and Lon A. Porter (a2)...


Owing to its photoluminescent properties and high surface area, porous silicon (por-Si) has shown great potential toward a myriad of applications including optoelectronics, chemical sensors, biocomposite materials, and medical implants. However, the native hydride-termination is only metastable with respect to surface oxidation under ambient conditions. Por-Si samples oxidize and degrade even more quickly when exposed to saline aqueous environments. Borrowing from solution phase synthetic methods, a selection of hydrosilylation reactions has been recently reported for functionalizing organic groups onto oxide-free, hydride-terminated porous silicon surfaces. Monolayers, bound through direct silicon-carbon bonds, are produced via thermal, microwave, Lewis acid, and carbocation mediated pathways. All of these wet, benchtop methods result in the formation of stable monolayers which protect the underlying silicon surface from ambient oxidation and chemical attack. However, no direct comparison of monolayer stability resulting from these diverse mechanisms has been reported. A variety of alkyl monolayers were prepared on porous silicon using the diverse hydrosilylation routes describe above and then immersed into a sequence of simulated gastric and intestinal fluids to replicate the conditions of potential por-Si biosensors or medicinal delivery systems in the human gastrointestinal tract. Degradation of the organic monolayers and oxidation of the underlying por-Si surfaces were monitored using both qualitative and semiquantitative transmission mode Fourier transform infrared spectroscopy (FTIR). Our initial results indicate that methods employing chemical catalysts often incorporate these species within the monolayer as defects, producing less robust surfaces compared to catalyst-free reactions. Regardless, monolayer protected por-Si samples demonstrated superior durability as opposed to the unfunctionalized controls.



Hide All
1. Inoue, A. and Hashimoto, K., Amorphous and Nanocrystalline Materials: Preparation, Properties, and Applications, (Springer, 2001).
2. Canham, L. T., Properties of Porous Silicon, (INSPEC, 1997).
3. Davis, M. E., Nature 417, 813821 (2002).
4. Rosoff, M., Nano-Surface Chemistry, (Marcel Dekker, 2002).
5. Porter, L. A. Jr., and Buriak, J. M., “Harnessing synthetic versatility toward intelligent interfacial design: organic functionalization of nanostructured silicon surfaces,” Chemistry of Nanostructured Materials (World Scientific, 2003) pp. 227259; J. M. Buriak, Chem. Rev. 102, 1271 - 1308 (2002).
6. Buriak, J. M., Stewart, M. P., Geders, T. W., Allen, M. J., Choi, H. C., Smith, J., Raftery, D., and Canham, L. T., J. Am. Chem. Soc. 121, 1149111502 (1999).
7. Boukherroub, R., Petit, A., Loupy, A., Chazalviel, J.-N., and Ozanam, F., J. Phys. Chem. B 107, 1345913462 (2003).
8. Bateman, J. E., Eagling, R. D., Worrall, D. R., Horrocks, B. R., and Houlton, A., Angew. Chem. Int. Ed. 37, 26832685 (1998); R. Boukherroub, S. Morin, D. D. M. Wayner, and D. J. Lockwood, Phys. Stat. Sol. A 182, 117-121 (2000).
9. Schmeltzer, J. M., Porter, L. A. Jr., Stewart, M. P., and Buriak, J. M., Langmuir 18, 29712974 (2002).
10. Snyder, R. G., Strauss, H. L., and Elliger, C. A., J. Phys. Chem. 86, 51455150 (1982).
11. Sander, L.C., Callis, J. B., and Field, L. R., Anal. Chem. 55, 10681075 (1983).



Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed