Authors: Say Yenh Hong
Source: eScholarship@McGill (McGill) (article, 2019-01-01)
Field: Materials Science — Biomaterials

Chemical transformation of chitosan oligosaccharides via solvent-free mechanochemistry; biomass valorization from ocean-sourced renewable feedstock to biobased platform chemicals Valorization of biomass waste has been postulated as the 'new frontier in green chemistry', moving the field beyond waste remediation and minimization.It has been boldly proposed that biomass waste could serve as complementary and alternative feedstocks to conventional fossilbased raw materials, leading to the emergence of a new paradigm: the biorefinery concept, i.e., envisaged as sustainable conversions of biomass into a broad spectrum of biobased products.In this work, we will explore a novel encapsulation design concept of employing a carbohydrate shell to encapsulate a biosensor envisaged for in vivo deployment.We will present a novel concept of producing modified oligosaccharide molecules with tailor-made properties intended for specialty/niche biomedicine biosensor application.To this end, the deliberate utilization of mechanical forces and energy by means of high speed ball milling (HSBM) to effect purposeful chemical transformations of recalcitrant oligosaccharides, as a non-thermal and solvent-free method for the preparation of useful new materials and platform molecules will be demonstrated, in this case, a tailor-made chitosan oligosaccharide.Chitosan oligosaccharides were reported in the literature to exhibit augmented antibacterial, antifungal, antitumour, immunoenhancing, lower haemolytic or hepatotropic profile, lower toxicity and other biological activities at the cellular or molecular level whilst forming thinner, more transparent, and smaller sized films than high molecular weight chitosan or polymeric chitin commonly used in many applications; the above properties would undeniably be desirable for biosensing applications.This work aims to demonstrate a proof-of-concept for producing high-value oligosaccharide biomaterials from abundant and renewable biomass carbohydrate residues (shellfish waste) which are inherently biodegradable, as a sustainable carbon based feedstock, hence fully embracing the concept of a waste-based biorefinery.The biomass conversion in this work is guided by the design philosophy of using milder processing/treatment conditions (enabled by mechanochemistry) in order to preserve Nature's highly functionalized biomacromolecules (valorized as precious resources), retaining a high proportion of the original chemical structure, functionality, and complexity, as a value creation strategy, thus departing from the normative tradition of synthesizing complex molecules from simpler starting precursors. Raw material ; Biomass (ecology) ; Mechanochemistry ; Pulp and paper industry ; Renewable energy ; Chitosan ; Chemical transformation ; Waste management ; Renewable resource ; Green chemistry ; Chemistry ; Organic chemistry ; Environmental science ; Biochemical engineering ; Engineering ; Ecology ; Catalysis biodegradable polymer synthesis and properties ; Nanocomposite Films for Food Packaging ; Nanomaterials for catalytic reactions