The preparation of pesticide-loaded microcapsules using biodegradable polymers and the balance between their sustained-release performance and small-size effects represent an effective strategy to enhance pesticide utilization efficiency. This study devised a one-step sol-gel self-assembly approach to fabricate abamectin-loaded microcapsules using biodegradable polyvinyl alcohol (PVA) and butylated hydroxytoluene (BHT) as raw materials. The results demonstrated that the reaction through hydrogen bonding by PVA and BHT at the o/w interface could generate shells and encapsulate pesticides to make microcapsules. Increasing PVA usage could reduce the particle size and enhance shell stability. The addition of BHT also improved the shell structure stability and encapsulation efficiency, whereas 3 %–7 % concentrations impeded the formation of the shell structure. Abamectin, which has a self-polymerizing ability, also increases microcapsule stability. A 54 °C temperature increase was maintained for 24 h to induce emulsion separation. Subsequent cooling and agitation prompts the reconstitution of pesticide-loaded microcapsules. The synergistic effect of the water-responsive mechanism, high encapsulation efficiency, and thicker shells endows nano-formulations with superior sustained-release performance compared to micro-scale formulations. The photostability of abamectin nanocapsules is significantly enhanced by 68.26 % compared to conventional suspensions, and the content of active ingredients remains at 50.54 % after 60 h of release under light conditions. Owing to their nanoscale sustained-release characteristics, their biological safety is improved by 36.43 %. The encapsulated Aba@BHT-PVA nano-system, leveraging excellent rainwater erosion resistance and leaf surface affinity, significantly prolongs its leaf retention time. Synergizing with the small-size effect, it demonstrates substantial enhancement in both the control efficacy and persistence against Plutella xylostella . Owing to its unique properties and easy regulation, this fabrication technique has great application value in the future.
Effectively prolonging the residence time of nanoprobes in the tumor region and reducing the accumulation of nanoprobes in the vital organs (for example, lung, liver and spleen) is crucial for high-efficiency photodynamic therapy (PDT) of cancer. Herein, we systematically report an ultra-small and highly stable nanoplatform with diameters of 4, 8 and 13 nm that exhibited excellent photodynamic therapeutic efficacy using Fe 3 O 4 @polymer-NPO/PEG-Glc@Ce6 nanoprobes. Based on the small size effect, the nanoprobes displayed lower cytotoxicity and excellent biocompatibility. Owing to the synergistic virtues of markedly active targeting and intrinsic small size effect, the Fe 3 O 4 @P-NPO/PEG-Glc@Ce6 nanoprobes can effectively prolong their residence time in the tumor region and reduce accumulation in the normal organs. Benefitting from the small size effect, the synthesized Fe 3 O 4 @P-NPO/PEG-Glc@Ce6 nanoprobes exhibited excellent tumor-targeting capability and photodynamic therapeutic efficacy by inhibiting the growth of tumors in mice under visible red light irradiation with a relatively lower power. The successful application of the small size effect in Fe 3 O 4 @P-NPO/PEG-Glc@Ce6 nanoprobes to significantly improve the PDT efficiency in our strategy suggests new building blocks for PDT of tumors and paves a new way for clinical therapies and translation in the near future.
W. Tang,L. Zhang,H. Huang,Y. Luo,C. Dong,D. Zhou,A. Li,W. Dong,G. Wang,Y. He
The development of efficient catalysts is essential to promote slow hydrogen reaction kinetics in alkaline solutions. Herein, an ultrathin ZIF-derived efficient HOR/HER electrocatalyst , with Co single-atom-anchored RuCo clusters on N-doped graphitized carbon nanosheets (RuCo/SANC NS), is designed and constructed by a step-by-step calcination strategy. In the RuCo/SANC NS, Co atoms dispersed in carbon nanosheets induce the formation of ultrasmall RuCo clusters and stabilize the RuCo clusters. Abundant coordinatively unsaturated Ru sites are formed on the surface of RuCo clusters due to the small size effect. The electronic structure of the Ru site is regulated by the alloying effect with Co, optimizing the adsorption energy to *H and *OH and accelerating the HER/HOR kinetics. The RuCo/SANC NS catalyst exhibits excellent mass activity with HER of 13.58 A/mg Ru and HOR of 3.85 A/mg Ru , which are about 35.35 and 48.13 times that of Pt/C.
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