Green Chemistry

To have impact, the plan must advance a bold vision of safer, more sustainable chemicals and processes at scale

by Joel Tickner, special to C&EN

Protease-activated receptor 2 (PAR2) is a G-protein-coupled receptor critical in regulating inflammation, pain, and physiological functions such as wound healing and epithelial barrier integrity. Chronic PAR2 activation contributes to numerous inflammatory and immune diseases, including inflammatory bowel disease (IBD), asthma, and arthritis, and plays a role in tumor progression by promoting proliferation, angiogenesis, and metastasis.

Chitin, a polysaccharide abundantly sourced from squid pens and crustacean shells, is a versatile biopolymer with diverse applications. α-chitin is predominant in crustacean shells, exhibiting a hierarchical nanofibrillar organization interspersed with proteins and calcium carbonate. Recent attention has focused on chitin nanocrystals (CNCs), produced via acid hydrolysis, which exhibit exceptional mechanical, thermal, and optical properties owing to their high aspect ratio, large surface area, and distinctive crystalline structure.

Chitin, the most abundant aminopolysaccharide, can be found in the exoskeleton of crustacean shells, a major waste product of the fishing industry. The water-soluble derivative of chitin, chitosan, acquired through a process of deacetylation affords derivatization and processability of this natural biopolymer. Traditionally, deacetylation processes utilizing harsh chemical conditions and high energy inputs limiting scalability and sustainable practices. Furthermore, these methods result in depolymerization, presenting low molecular weight fragments.