Facile Surface Modification of Hydroxylated Silicon Nanostructures Using Heterocyclic Silanes

Heterocyclic silanes containing Si-N or Si-S bonds in the ring undergo a ring opening reaction with -OH groups at the surface of porous Si nanostructures to generate -SH or -NH functional surfaces, grafted via O-Si bonds. The reaction is substantially faster (0.5-2 h at 25 degrees C) and more efficient than hydrolytic condensation of trialkoxysilanes on similar hydroxy-terminated surfaces, and the reaction retains the open pore structure and photoluminescence of the quantum-confined silicon nanostructures. The chemistry is sufficiently mild to allow trapping of the test protein lysozyme, which retains its enzymatic activity upon release from the modified porous nanostructure.