Biomimic Light Trapping Silicon Nanowire Arrays for Laser Desorption/Ionization of Peptides

This article describes a low cost method of generating silicon nanowire arrays that have similar structure and light trapping ability as moth-eye for matrix-free laser desorption/ionization mass spectrometry analysis of small molecules without matrix peak interference. The nanowire array is produced by combining low cost nanosphere lithography and metal nanoparticle-assisted chemical etching of silicon. Owing to their excellent light trapping ability over broad spectral range, silicon nanowire arrays can absorb incoming laser light efficiently, and convert laser energy to heat, which allows efficient desorption/ionization of intact peptide/proteins without matrix. Compared to existing matrix-free substrate such as porous silicon substrates, the biomimic silicon nanowire arrays are better in terms of lower laser energy, structural tunability, and low spatial resistance.