Poly(alkyl ethylene phosphonate)s with different alkyl side chains exhibit significant differences in their degradation behavior. Three novel 2-alkyl-2-oxo-1,3,2-dioxaphospholanes, cyclic monomers for the ring-opening polymerization (ROP) toward poly(alkyl alkylene phosphonate)s, were synthesized by robust two-or three-step protocols in reasonable yields and high purity. The polymerization was promoted by the organocatalysts 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) and proceeded with high control over molecular weight and narrow molecular weight distributions (Đ < 1.2) up to full conversion. These polymers with methyl, ethyl, and isopropyl side chains are perfectly soluble in water (up to 25 mg mL −1 ) without a temperature-dependent phase separation. They showed no toxicity against HeLa cells after 24 h of incubation at any tested concentration. Polymers with butyl side chains exhibit decreased solubility and concentrationdependent cloud point temperatures and show toxicity against HeLa cells at concentrations above 25 μg mL −1 . The polymers showed no acetylcholinesterase inhibition. All polymers exhibited significantly different degradation times under both neutral as well as basic conditions (variation of the alkyl side chain allowed stabilities from 8 h up to 6 days).
Living organisms compartmentalize their catalytic reactions in membranes for increased efficiency and selectivity. To mimic the organelles of eukaryotic cells, we develop a mild approach for in situ encapsulating enzymes in aqueous-core silica nanocapsules. In order to confine the sol-gel reaction at the water/oil interface of miniemulsion, we introduce an aminosilane to the silica precursors, which serves as both catalyst and an amphiphilic anchor that electrostatically assembles with negatively charged hydrolyzed alkoxysilanes at the interface. The semi-permeable shell protects enzymes from proteolytic attack, and allows the transport of reactants and products. The enzyme-carrying nanocapsules, as synthetic nano-organelles, are able to perform cascade reactions when enveloped in a polymer vesicle, mimicking the hierarchically compartmentalized reactions in eukaryotic cells. This in situ encapsulation approach provides a versatile platform for the delivery of biomacromolecules.
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