Tandem Chain Walking Polymerization and Atom Transfer Radical Polymerization for Efficient Synthesis of Dendritic Nanoparticles for Bioconjugation

Abstract

A tandem chain walking polymerization (CWP) and ATRP was developed for efficient synthesis of nanoparticles for bioconjugation. Using the chain walking palladium-α-diimine catalyst (catalyst 1), dendritic polymers bearing multiple initiation sites were synthesized and used as macro-initiators for subsequent Cu(I)-mediated ATRP. Control of molecular weight and size of the water soluble core-shell polymeric nanoparticles was achieved by tuning reaction conditions. Addition of N-acryloyloxysuccinamide (NAS) monomer at the end of the ATRP afforded NHS activated polymer nanoparticles. Conjugation with both small dye molecule and protein (ovalbumin) yielded nanoparticle conjugates with relatively high dye or protein per particle ratio. With the efficient synthesis and good biocompatibility, these nanoparticles may find many potential applications in bioconjugation.

Chain Walking Ethylene Copolymerization with an ATRP Inimer for One‐Pot Synthesis of Hyperbranched Polyethylenes Tethered with ATRP Initiating Sites

“…Pd-diimine catalysts have been reported to be tolerant of the a-bromoester functionality. [14] The successful incorporation of BIEA into the copolymers through the enchainment of the acrylate group was confirmed by NMR elucidation of the copolymer structure. A representative 1 H NMR spectrum of PE-BIEA-1 is shown in Figure 1, along with those of the BIEA comonomer and the homopolyethylene, HomoPE, for comparison.…”

“…[11,13] The combination of chain walking polymerization (CWP) with other polymerization techniques is needed in order to incorporate other types of comonomers at high percentages. Guan et al [14] showed an example by coupling the CWP technique with ATRP and synthesized hyperbranched polyethylenes tethered with ATRP initiating sites by copolymerizing of ethylene with functional alk-1-enes bearing a-bromoester sites using Pd-diimine catalysis.…”

Complex Branched Polyolefin Generated from Quasi-living Polymerization of 4-Methyl-1-pentene Catalyzed by α-Diimine Palladium Catalyst

“…[7] Additionally, a tandem polymerization strategy combining chain walking polymerization and atom transfer radical polymerization (ATRP) was also developed to synthesize functionalized copolymers with core-shell structure. [8] In contrast to ethylene polymerization, homopolymerizations of linear a-olefins such as propylene, 1-hexene, and 1-octene catalyzed by a-diimine palladium catalysts generally lead to branched poly(a-olefin)s. [9] Comparing to linear a-olefins, branched a-olefins are scarcely reported as polymerization monomers with late transition metal complexes in the current literatures due to their enhanced steric bulk. One example is copolymerization of ethylene and 3,3-dimethyl-1-butene reported by Xiang and Ye with Pd-diimine catalyst, and 3,3-dimethyl-1-butene can be directly incorporated in the copolymer.…”

Solubilization of single-walled carbon nanotubes by entanglements between them and hyperbranched phenolic polymer

“…The same trends were observed in the other hyperbranched polymers and dendrimers. [23,24] (Insert Table 1 (Insert Figures 3 and 4 here) …”