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 °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.