The present invention relates to a process which uses blue light to form bio-organic coated silver and gold nanoparticles for various applications. The present invention particularly relates to increasing the rates of reaction and widening the scope of tethering a range of biomolecules on the metal nanoparticles. The examples demonstrate that the biomolecules immobilized on the nanoparticles still retain many aspects of their structural elements which allow them to bind to their native binding partners and/or retain structural epitopes which allow them to be identified by antibodies specific to them, thus opening up scope of using such coated nanoparticles for functionalized and specific applications.