Synthesis of proton caged disulphide compounds for gold nanoparticle functionalization

The pH plays a fundamental role in many biological systems, and it is important to be capable of monitoring and manipulating it. A method for intracellular pH control has been recently developed based on a proton caged compound (PCC), which releases protons upon irradiation with light of proper wavelength. Intracellular modulation of PCC uptake can be achieved by gold nanosized vectors. This, however, is conditioned by the possibility of conjugating PCCs and vectors. Here, we present the synthesis of purposely designed proton caged disulphide sulphonyl urethanes, which bind gold nanoparticles through the disulphide bridge and display photoreactivity through an o-nitrophenyl moiety. The new compounds have been characterized by FTIR, 1H NMR, TEM and TGA and their photoreactivity in the UV range has been probed, after functionalizing them with gold nanoparticles.