We report here a novel direct method for the syntheses of primary aminoalkyl methacrylamides that requires mild reagents and no protecting group chemistry. The reversible addition‐fragmentation chain transfer polymerization (RAFT) of the aminoalkyl methacrylamide revealed to be highly efficient with 4‐cyanopentanoic acid dithiobenzoate (CTP) as chain transfer agent and 4,4′‐azobis(4‐cyanovaleric acid) (ACVA) as initiator. Cationic amino‐based homopolymers of reasonably narrow polydispersities (Mw/Mn < 1.30) and predetermined molecular weights were obtained without recourse to any protecting group chemistry. A range of block and random copolymers were also synthesized via the RAFT process. The homopolymers and copolymers were characterized by aqueous conventional and triple detection gel permeation chromatography systems. Furthermore, the primary amine‐based methacrylamide monomers and polymers revealed to be highly stable both with the primary amino group in the protonated and deprotonated form. We have also demonstrated that stabilized gold nanoparticles can be generated with the RAFT‐synthesized amine‐based polymers via a photochemical process. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4984–4996, 2008

Well-defined glycopolymers containing linear and cyclic carbohydrate moieties as pendent groups were prepared by reversible addition fragmentation chain transfer polymerization (RAFT). The RAFT synthesized glycopolymers were used for the aqueous synthesis of stabilized glyconanoparticles. The in situ reduction of the glycopolymers and HAuCl4 resulted in the formation of highly stable modified gold nanoparticles with diameters ranging from 40 to 80 nm in aqueous media. Multifunctional glyconanoparticles were also generated in the presence of varying amounts of biotinylated-polyethyleneglycol (bio-PEG-SH) having terminal thiol groups. The gold nanoparticles underwent aggregation in the presence of streptavidin as revealed by UV-vis spectroscopy. The availability of the biotin for conjugation to streptavidin was also confirmed using surface plasmon resonance (SPR).

Protein stabilized, water soluble gold nanoparticles are essential for biomedicines and biotechnology. Bovine Serum Albumin (BSA) is one of the most abundant proteins. It has a remarkable ability of binding and transporting materials across cell membrane that makes it ideal for drug delivery and very useful for pharmaceutical industry. Herein, we explored the direct synthesis of BSA stabilized gold nanoparticles via a simple photochemical process. BSA stabilized gold nanoparticles are synthesized in one step, using Irgacure (I-2959) as photoinitiator. UV radiation facilitates the easy one step synthesis of protein stabilized gold nanoparticles without any denaturation of the protein, during the process. Polyacrylamide Gel (PAGE) shows that there is no difference in the bands height and mobility of native BSA and UV irradiated BSA. PAGE results are further confirmed by fluorescence spectroscopy of native and UV irradiated BSA. BSA/PEG (polyethylene glycol) mixed monolayer stabilized gold nanoparticles have also been prepared in one step using the photochemical process. Different ratios of PEG to BSA are used to evaluate the particle size and the size distribution of gold nanoparticles. Transmission electron microscope (TEM) and dynamic light scattering (DLS) confirm the presence of nearly monodisperse mixed layer stabilized gold nanoparticles.