Sers Sensing Of Sub-Nanoliter Analyte On Diatom Biosilica Using Inkjet Printing

Diatoms are unicellular algae which have photonic-crystal-like biosilica frustules consisting of many pores. Each diatom frustule has a dimension around 10 similar to 20 mu m and can be used as a miniaturized biosensor. In this article, we demonstrate surface-enhanced Raman scattering (SERS) sensing of sub-nanoliter analyte on diatom biosilica with self-assembled silver nanoparticles (Ag NPs). An inkjet printer is used to dispense multiple similar to 100 pico-liter volume analyte droplets with pinpoint accuracy and precision onto each individual diatom frustule. Experimental results show up to 3x higher SERS signals of R6G on diatom compared with those from conventional colloidal SERS substrates. Furthermore, down to 10(-14)M R6G detection ability was also demonstrated through the inkjet printing strategy.