Synthesis of Polypeptides and Poly(α-hydroxy esters) from Aldehydes Using Strecker Synthesis

This report presents a versatile approach for the synthesis of new polypeptide and polyester-based biomaterials. The well-established Strecker reaction was utilized, with hexanal serving as the model aldehyde, to synthesize α-amino and α-hydroxy acids as monomer units for the polymer system. Following the formation of the corresponding amino and hydroxy acid monomers, they were subsequently converted to N-carboxy and O-carboxy-anhydrides. The resultant cyclic anhydride molecules were then polymerized via ring-opening polymerization to yield the corresponding polypeptides and polyesters. This report establishes a straightforward methodology for the synthesis of new polypeptide and poly(a-hydroxy acid)-based biomaterials, thereby expanding the existing library of polymers for various biomedical applications.

Base-free Air Oxidation of Chitin-derived Glucosamine to Glucosaminic Acid by Zinc Oxide-supported Gold Nanoparticles

In this study, glucosaminic acid (GlcNA) was produced with the highest yield of ~85% from chitin biomass-derived glucosamine (GlcN) at 35 °C under atmospheric air in water, by using zinc oxide-supported gold nanoparticles (Au/ZnO). The Au/ZnO catalyst prepared by the deposition-precipitation (DP) method displayed remarkably superior catalytic performance to that prepared by the deposition-reduction (DR) method, which led to > 2-fold enhancement in product yield. A lower apparent activation energy (E a ) was observed over the Au/ZnO (DP) for GlcNA formation compared with the Au/ZnO (DR) catalyst. Based on control tests and structural characterizations, the average particle size of Au nanoparticles (NPs) and the surface oxygen vacancy (O v ) sites were the crucial factors on the catalytic activity. The work puts forward a green, mild and efficient approach to synthesize valuable amino acid from ocean-based chitin biomass resources with air as the oxidant, adding on new possibilities of chitin biorefinery.

Design, synthesis and biological applications of glycopolypeptides

Carbohydrates play essential structural and biochemical roles in all living organisms. Glycopolymers are attractive as well-defined biomimetic analogs to study carbohydrate-dependent processes, and are widely applicable biocompatible materials in their own right. Glycopolypeptides have shown great promise in this area since they are closer structural mimics of natural glycoproteins than other synthetic glycopolymers and can serve as carriers for biologically active carbohydrates. This review highlights advances in the area of design and synthesis of such materials, and their biomedical applications in therapeutic delivery, tissue engineering, and beyond.

Ring opening polymerization of α-amino acids: advances in synthesis, architecture and applications of polypeptides and their hybrids

This review provides a comprehensive overview of the latest advances in the synthesis, architectural design and biomedical applications of polypeptides and their hybrids.

Biodegradable Poly(Acetonide Gluconic Acid) for Controlled Drug Delivery

We report here on the synthesis, characterization, degradation, and drug release of acetal-protected gluconic acid-based poly(α-hydroxy ester). This polyester was synthesized by ring-opening polymerization of O-carboxyanhydride of acetal-protected gluconic acid. The polymer undergoes hydrolytic degradation under mild acidic media, whereas minimal degradation takes place under physiological pH. Under acidic conditions, the acetal-protecting groups are hydrolyzed, resulting in a water-soluble polyester with saccharide side chains that erodes from the surface, leaving the bulk of the polymer matrix intact. At pH 3.5, zero-order kinetics was maintained for 50 days accounting for ∼75% drug release. These biodegradable, pH-responsive, sustained zero-order release kinetics of the polymer have application as drug carriers for oral drug delivery or medical implants or also for nonmedical applications.