RESUMO
This work aims to apply water radiolysis-mediated green synthesis of amphiphilic core-shell water-soluble chitosan nanoparticles (WCS NPs) via free radical graft copolymerization in an aqueous solution using irradiation. Robust grafting poly(ethylene glycol) monomethacrylate (PEGMA) comb-like brushes were established onto WCS NPs modified with hydrophobic deoxycholic acid (DC) using two aqueous solution systems, i.e., pure water and water/ethanol. The degree of grafting (DG) of the robust grafted poly(PEGMA) segments was varied from 0 to ~250% by varying radiation-absorbed doses from 0 to 30 kGy. Using reactive WCS NPs as a water-soluble polymeric template, a high amount of DC conjugation and a high degree of poly(PEGMA) grafted segments brought about high moieties of hydrophobic DC and a high DG of the poly(PEGMA) hydrophilic functions; meanwhile, the water solubility and NP dispersion were also markedly improved. The DC-WCS-PG building block was excellently self-assembled into the core-shell nanoarchitecture. The DC-WCS-PG NPs efficiently encapsulated water-insoluble anticancer and antifungal drugs, i.e., paclitaxel (PTX) and berberine (BBR) (~360 mg/g). The DC-WCS-PG NPs met the role of controlled release with a pH-responsive function due to WCS compartments, and they showed a steady state for maintaining drugs for up to >10 days. The DC-WCS-PG NPs prolonged the inhibition capacity of BBR against the growth of S. ampelinum for 30 days. In vitro cytotoxicity results of the PTX-loaded DC-WCS-PG NPs with human breast cancer cells and human skin fibroblast cells proved the role of the DC-WCS-PG NPs as a promising nanoplatform for controlling drug release and reducing the side effects of the drugs on normal cells.
RESUMO
OBJECTIVE: An aptamer specifically binding to diethyl thiophosphate (DETP) was constructed and incorporated in an optical sensor and electrochemical techniques to enable the specific measurement of DETP as a metabolite and a biomarker of organophosphate exposure. RESULTS: A DETP-bound aptamer was selected from the library using capillary electrophoresis-systematic evolution of ligands by exponential enrichment (CE-SELEX). A colorimetric method revealed that the aptamer had the highest affinity for DETP, with a mean Kd value (± SD) of 0.103 ± 0.014 µM. The docking results and changes in resistance showed that the selectivity of the aptamer for DETP was higher than that for the similar structures of dithiophosphate (DEDTP) and diethyl phosphate (DEP). The altered amplitude of cyclic voltammetry showed a linear range of DETP detection covering 0.0001-10 µg/ml with a limit of detection of 0.007 µg/ml. The recovery value of a real sample of pH 7 was 97.2%. CONCLUSIONS: The current method showed great promise in using the DETP-specific aptamer to detect the exposure history to organophosphates by measuring their metabolites, although degradation of organophosphate parent compounds might occur.
