Degradable polyesters via ring-opening polymerization of functional valerolactones for efficient gene delivery.

Degradable polymers as gene and drug carriers are emerging as one of the most promising types of materials in the biomedical and pharmaceutical areas. Herein, we report the synthesis of a series of block co-polyesters (B1-B6) and random co-polyesters (C1-C4) via ring-opening polymerization of tertiary amine-bearing valerolactone and alkylated valerolactone monomers. These polymers can completely inhibit the electrophoretic migrations of plasmid DNAs (pDNAs) at a w/w ratio of 2-6. The polyplexes of these polymers with pDNAs were steadily formed in a narrow range of sizes (75 to 220 nm) and could be effectively internalized into the cytoplasm. The results of transfection experiments showed that the block copolymers generally exhibited better performance than their random counterparts and the aliphatic chain lengths on the backbone of the polymers obviously affected the transfection efficiency (TE). Block copolymer B5 with n-octyl chains generated the best TE in Hek293T cells, which was 2.2 fold that of polyethylenimine (PEI) 25k under the optimal conditions. Moreover, these polymers were found to be more biocompatible compared to PEI 25k, and showed degradable properties. Our results suggest that these polymers are potentially reliable/efficient non-viral gene vectors.

The surface groups of polystyrene nanoparticles control their interaction with the methanogenic archaeon Methanosarcina acetivorans.

A better understanding of the interaction between nanoplastics and archaea is crucial to fill the knowledge gaps regarding the ecological safety of nanoplastics. As a vital source for global methane emissions, methanogenic archaea have unique cell membranes that are distinctly different from those in all other forms of life, little is known about their interaction with nanoplastics. Here, we show that polystyrene nanoparticles functionalized with sulfonic acid (PS-SO3H) and amino (PS-NH2) interact with this methanogenic archaeon in distinct ways. Although both of them have no significant phenotype effects on Methanosarcina acetivorans C2A, these nanoparticles could affect DNA-mediated transposition of this methanogenic archaeon, and PS-SO3H also downregulated nitrogen fixation, nitrogen cycle metabolic process, oxidoreductase activity, etc. In addition, both nanoplastics decreased the protein contents in the extracellular polymer substances (EPS), with distinct binding sequences to the functional groups of the EPS. The single particle atomic force microscopy revealed that the force between the amino group and the M. acetivorans C2A was greater than that of sulfonic acid group. Our results exhibit that the surface groups of polystyrene nanoparticles control their risk on the methanogenic archaea, and these effects might influence their contribution on global methane emission.