Abstract: A method of synthesizing ligand-conjugated gold nanoparticles (AuNPs) is disclosed. The method comprises: a) providing an amine-modified silica particle; b) providing a solution comprising Au+3 ions; c) suspending the amine-modified silica particle in the solution comprising Au+3 ions; d) allowing the Au3+ ions to be adsorbed and/or immobilized onto the surface of the amine-modified silica particle; e) exposing the Au3+ ions immobilized onto the surface of the amine-modified silica particle to radiation to obtain bare gold nanoparticles (AuNPs) adsorbed and/or immobilized onto the surface of the amine-modified silica particle, wherein the bare AuNPs are without organic surface modifications; and f) reacting a ligand with the bare AuNPs adsorbed and/or immobilized onto the surface of the amine-modified SiNP and thereby obtain ligand-conjugated gold nanoparticles (AuNPs).

Abstract: A method of synthesizing ligand-conjugated gold nanoparticles (AuNPs) is disclosed. The method comprises: a) providing an amine-modified silica particle; b) providing a solution comprising Au+3 ions; c) suspending the amine-modified silica particle in the solution comprising Au+3 ions; d) allowing the Au3+ ions to be adsorbed and/or immobilized onto the surface of the amine-modified silica particle; e) exposing the Au3+ ions immobilized onto the surface of the amine-modified silica particle to radiation to obtain bare gold nanoparticles (AuNPs) adsorbed and/or immobilized onto the surface of the amine-modified silica particle, wherein the bare AuNPs are without organic surface modifications; and f) reacting a ligand with the bare AuNPs adsorbed and/or immobilized onto the surface of the amine-modified SiNP and thereby obtain ligand-conjugated gold nanoparticles (AuNPs).

Abstract: A method of synthesizing polyethyleneimine with a substantially linear backbone is disclosed. The method comprises exposing ethylenediamine dissolved in a solution to electromagnetic radiation for a sufficient time to polymerize the ethylenediamine and thereby resulting in formation of polyethylenimine with a substantially linear backbone in the solution. A method of synthesizing a homopolymer with a substantially linear backbone is also disclosed. In addition, a composition comprising polyethylenimine synthesized from the aforementioned method is disclosed, in which the polyethylenimine comprises a backbone conformation that is substantially linear and has a distribution of molecular weights (MW) ranging from 1 kDa to 200 kDa; and the polyethyleneimine has no cytotoxicity at a concentration of 12 ?g/ml.