Dual faced SERS nanoparticles equipped with tri-functions for target drug delivering into single cell

We reports an approach to fabricate dual-faced polystyrene beads (DFPSBs) with tri-functions of tumor cell recognition, drug delivery, and real-time Raman sensing. Onestep oxygen-plasma treatment process was used to etch commercially available fluorescent polystyrene beads into a corrugated upper hemisphere and simultaneously change the entire surface with carboxylic groups. After depositing gold onto the corrugated hemisphere for surface enhanced Raman scattering (SERS) while leaving the other smooth and clean hemisphere for fluorescence detection, the DFPSBs are formed with dual-surfaces of plasmonic gold semishells on the top and fluorescent carboxylated polystyrene at the bottom. Sulfo-NHS-SS-biotin disulfide linkers and anti-CD44 antibodies can be modified and added onto the top gold surfaces and the bottom carboxyl groups through Au-S and peptide bonds, respectively. Then, the surface-modified DFPSB suspension can be employed to target overexpressive glycoproteins (CD44) on the surfaces of cancer cells and release their loads via the cleavage of disulfide bonds in the cytoplasm environment. These anti-CD44-modified DFPSBs exhibit a 12-fold cancer targeting ability on HeLa cells when compared to a normal chondrocyte cell.