Polymer-Based Bioorthogonal Nanocatalysts for the Treatment of Bacterial Biofilms.

Bioorthogonal catalysis offers a unique strategy to modulate biological processes through the in situ generation of therapeutic agents. However, the direct application of bioorthogonal transition metal catalysts (TMCs) in complex media poses numerous challenges due to issues of limited biocompatibility, poor water solubility, and catalyst deactivation in biological environments. We report here the creation of catalytic "polyzymes", comprised of self-assembled polymer nanoparticles engineered to encapsulate lipophilic TMCs. The incorporation of catalysts into these nanoparticle scaffolds creates water-soluble constructs that provide a protective environment for the catalyst. The potential therapeutic utility of these nanozymes was demonstrated through antimicrobial studies in which a cationic nanozyme was able to penetrate into biofilms and eradicate embedded bacteria through the bioorthogonal activation of a pro-antibiotic.

Fast and highly efficient adsorption of cationic dyes by phytic acid crosslinked ß-cyclodextrin.

In this study, a novel adsorbent (PA-ß-CD) capable of fast and efficient adsorption of cationic dyes was successfully prepared by the poly-condensation reaction of phytic acid (PA) and ß-cyclodextrin (ß-CD). Results showed that PA-ß-CD exhibited high adsorption capacities of 1095, 2005.58, 1736.32, and 1930.23 mg/g for methylene blue (MB), basic green 4 (MG), astrazon pink FG (FG), and crystal violet (MV), respectively. In addition, the adsorption of cationic dyes on PA-ß-CD was very fast, and most of cationic dyes were adsorbed in the first 2 min. Moreover, PA-ß-CD could selectively adsorb the cationic dye from a cationic/anionic dye mixture. Adsorption data revealed that the adsorption kinetics fitted the pseudo-second-order model well, and the isotherms were well described by a Langmuir isotherm model. The regeneration efficiency of the adsorbent remained above 90% after the fifth cycle. The present work confirmed that PA-ß-CD shows great potential in the treatment of dye wastewater.

Toughening of Poly(l-Lactide) with Branched Polycaprolactone: Effect of Chain Length.

In this work, a series of branched polycaprolactone (BPCL) samples with different ε-caprolactone (CL) chain lengths were synthesized and used to toughen poly (lactic acid) (PLA). The spherical structure increased the free volume, facilitating the free movement of the PLA chain segment and increasing the ductility. In addition, the hydrogen bonds between the multi-terminal hydroxyl group of BPCL x and PLA improved the interaction between them. The glass-transition temperatures (T g) and crystallization temperatures (T c) of the blends were significantly lower than those of PLA, and these temperatures increased with the chain length of polycaprolactone. BPCL x increased the crystallization rate of PLA through heterogeneous nucleation. A longer chain length of CL increased the mutual entanglement in the blends, reduced the hydrogen bonding between BPCL x and PLA, and increased the entanglement of BPCL x chains. When the chain length of CL was 6, the impact strength and elongation at break of the PLA/BPCL blends exhibited an increase of 151.72 and 465.8%, respectively, as compared with PLA.

Cross-linking of poly(dimethylaminoethyl methacrylate) by phytic acid: pH-responsive adsorbent for high-efficiency removal of cationic and anionic dyes.

A new high-efficiency adsorbent for cationic and anionic dyes named PAGD was synthesized via polymerization of dimethylaminoethyl methacrylate by employing glycidyl-methacrylate-modified phytic acid as a cross-linker. The experiment demonstrated that PAGD is pH-sensitive, and the maximum adsorption capacities of anionic dye Reactive Red 24 (RR24) and cationic dye Fuchsin Basic (FB) were 1871.23 and 482.54 mg g-1, respectively. To the best of our knowledge, there has been no previous report on a dye adsorbent possessing an adsorption capacity of over 465 mg g-1 for RR24. The excellent adsorption abilities toward RR24 are due to the introduced phytic acid groups, which could promote protonation of tertiary amine groups under acid pH conditions. Moreover, PAGD is able to selectively remove RR24 in a mixed solution of cationic dye and RR24. The adsorption isotherms and kinetics of PAGD fit well with the Langmuir isotherm and pseudo-second-order kinetic model, respectively. These results imply that PAGD is a promising adsorbent for removal of both cationic and anionic dyes.