Temperature and pH dual responsive 2-(dimethylamino)ethanethiol modified starch derivatives via a thiol-yne reaction for drug delivery

Temperature responsive crosslinked starch-kraft lignin macromolecule

Starch is a natural polymer with a relatively simple structure and limited solubility in water. Kraft lignin (KL) is a complex biopolymer obtained as a by-product from the delignification of wood and grasses. The present work reports developing a temperature-responsive high molecular weight macromolecule from crosslinking KL and starch (KLS). The NMR and XPS analyses quantified the changes in the aromatic and anhydroglucose units of KL and starch, observing a higher content of C-O-C bonds, which confirms the presence of glycerol ether cross-linkages between starch and KL in KLS. The rheological analysis of KLS dispersions revealed the formation of a thermo-responsive structured network. The temperature-dependent water solubility and rheological characteristics of KLS were related to the presence of hydrophilic starch chains, crosslinking degree, and physicochemical characteristics of KL. The incorporation of KL and ether crosslinks increased the thermal stability of KLS. Because of its multiple functional groups and large molecular weight (3.6-4.2 × 10⁵ g/mol) that was arranged in an extended globular shape, KLS-5 formed a gel-like structure after a heating-cooling treatment. Overall, the results confirmed that incorporating lignin in starch would fabricate sustainable materials with potentially altered applications, such as temperature-responsive hydrogels and films.

Progress and prospects of modified starch-based carriers in anticancer drug delivery

Recently, the role of starch-based carrier systems in anticancer drug delivery has gained considerable attention. Although there are same anticancer drugs, difference in their formulations account for unique therapeutic effects. However, the exploration on the effect-enhancing of anticancer drugs and their loading system by modified starch from the perspective of carrier regulation is still limited. Moreover, research on the reduced toxicity of the anticancer drugs due to modified starch as the drug carrier mediated by the intestinal microenvironment is lacking, but worth exploring. In this review, we examined the effect of modified starch on the loading and release properties of anticancer drugs, and the effect of resistant starch and its metabolites on intestinal microecology during inflammation. Particularly, the interactions between modified starch and drugs, and the effect of resistant starch on gene expression, protein secretion, and inflammatory factors were discussed. The findings of this review could serve as reference for the development of anticancer drug carriers in the future.