Synthesis of gold nanoparticles on surfaces has been accomplished by the incubation of poly(dimethylsiloxane)(PDMS) films in tetrachloroauric(III) acid and chitosan solution at room temperature and 4
C. One importantpoint in the present study is that the synthesis selectively occurred on the PDMS surface. These observations aresubstantially different from the reaction in solution, in which no particles can be formed at room temperature.Computation of surface plasmon bands (SPBs) based on Mie theory suggests that the particles are partially coatedby chitosan molecules, and the experimental results confirm the theoretical calculations. The proposed mechanismis that chitosan molecules adsorbed or printed on the PDMS surfaces act as reducing/stabilizing agents. Furthermore,PDMS films patterned with chitosan could induce localized synthesis of gold nanoparticles in regions cappedwith chitosan only. In this way, colloidal patterns were fabricated on the surfaces with high spatial selectivitysimultaneously with the synthesis of the particles. Surface-induced fluorescence quenching was observed in theregions capped with gold nanoparticles as well.