A Simple Route to Aqueous Suspensions of Degradable Copolymer Nanoparticles from Radical Ring-Opening Polymerization-Induced Self-Assembly (rROPISA)

Degradable polymer nanoparticles are almost exclusively obtained by formulation of preformed degradable polymers, such as aliphatic polyesters, thus resulting is very low nanoparticle concentrations and limited structural diversity. On the other hand, many different vinyl polymers can be obtained by polymerization in aqueous dispersed media, but their non-degradability limits their use especially in the biomedical field. Herein, we combined the best of both worlds by developing a two-step radical ring-opening copolymerization-induced self-assembly (rROPISA) process, allowing to generate aqueous suspensions of narrowly dispersed, degradable vinyl copolymer nanoparticles at 15 wt.% solid contents, containing cyclic ketene acetal (CKA) units in the nanoparticle core. This strategy relied on rROPISA in DMF, followed by a simple transfer step to water. It was successfully applied to the three main CKAs used in rROP and yielded nanoparticles of ~80–215 nm in diameter with tunable amount of CKA up to 21 mol.%. Successful incorporation of ester groups in the copolymers was demonstrated by hydrolytic degradation of both the copolymers and the nanoparticles. The nanoparticles’ cytocompatibility was then established by cell viability assays and cell morphology observation with three representative healthy cell lines. Not only this synthetic strategy could be of great potential for drug delivery applications, but it can also be beneficial to other research fields to yield more environmentally friendly materials involving the use of latexes, such as paints or coatings.

Подбор композиции биопрепаратов для обработки семян кукурузы и определение ее действия на всхожесть

Options for the two biological products composition selecting as a percentage of quantity are de-scribed. Biological products Gliocladin-SC and Trichodermin-SC based on fungi of the genus Tricho-derma in a tank mixture can enhance the biological activity of the applied working solutions. In six exper-iments performed, 54 variants of aqueous suspensions for treating corn seeds were tested.

Temperature oscillations during photoinduced heating of aqueous suspensions of silicon nanoparticles

Temperature oscillations (pulsations) were detected in aqueous suspensions of silicon (Si) nanoparticles NPs under laser irradiation with highly absorbed light. The temperature pulsation frequency was found to depend on the NPs concentration in suspension and laser irradiation power. The observed phenomenon is assumed to be caused by the local overheating of Si NPs close to the boiling point of water, while the average heating of the surrounding liquid was insignificant. The observed phenomenon is discussed in view of potential applications in local photo-induced hyperthermia of cancer.