Advances in Coating Chemistry in Deriving Soluble Functional Nanoparticle

Nanoparticle-based probes are emerging as alternatives to molecular probes with several advantages. A variety of water-soluble functional nanoparticles and nanobioconjugates need to be prepared and tested for this research. Development of appropriate coating chemistries is the key in deriving such functional nanoparticles. Herein we summarize different coating approaches those we have developed and compared them in the context of currently available coating methods, for the synthesis of soluble functional nanoparticles. We have focused on conventional ligand exchange, interdigited bilayer strategy, silica coating, polyacrylate coating, and imidazole based polymer coating and found that cross-linked coating, specifically by polyacrylate, provides a superior colloidal stability of nanoparticles. The robust coating provides the opportunity to explore various conjugation chemistries involving nanoparticle and to derive different soluble nanobioconjugates. A library of functional nanoprobes with hydrodynamic diameters of 10-100 nm are synthesized with these coating approaches which are composed of different nanoparticles (e.g., metal, metal oxide, or semiconductor) and affinity molecules (e.g., oligonucleotide, peptide, antibody, vitamins, etc.) and can be explored for cellular and subcellular imaging and ultrasensitive biosensing applications.