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A systematic protocol to fabricate self-assembly deoxycholate-chitosan nanospheres (DC-CsNS) by c-ray pre-irradiation and chemical modification was studied. Hydrophobic deoxycholic acid moieties were chemically conjugated to pre-irradiated chitosan. The influences of chitosan physical forms (i.e., colloid and flake) during irradiation, radiation doses, and the reaction system (heterogeneous or homogeneous) on the chemical modification and the particle shape and size were investigated. Pre-irradiation of chitosan in colloidal form produced smaller DC-CsNS particle size than that of flake form. In the heterogeneous reaction, the pre-irradiated dose influenced the DC-CsNS particle size, whereas in the homogeneous reaction all pre-irradiation doses gave an identical average size range of 30-50 nm. By pre-irradiation (10 kGy) of chitosan in colloidal form before heterogeneous chemical conjugation, it is possible to obtain DC-CsNS with an average size of 46 nm. DC-CsNS of about 50 nm in size could also be synthesized using homogeneous chemical conjugation onto non-irradiated chitosan with the addition of N-hydroxysuccinimide (NHS).

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.

Objective An aptamer speci cally binding to diethyl thiophosphate (DETP) was constructed and incorporated in an optical sensor and electrochemical impedance spectroscopy (EIS) to enable the speci c measurement of DETP as a metabolite and a biomarker of exposure to organophosphates.Results DETP-bound aptamer was selected from the library using capillary electrophoresis-systematic evolution of ligands by exponential enrichment (CE-SELEX). A colorimetric method revealed the aptamer had the highest a nity to DETP with a mean Kd value (± SD) of 0.103 ± 0.014 µM. Changes in resistance using EIS showed selectivity of the aptamer for DETP higher than for dithiophosphate (DEDTP) and diethyl phosphate (DEP) which have similar structure and are metabolites of some of the same organophosphates. The mean (± SD) of percentage of altered resistance of DETP was calculated at 47.5 ± 8.8% which was signi cantly higher than of DEDTP at 14.3 ± 1.5% and of DEP at 7.0 ± 1.4%.Conclusions The current method showed a great promise in using the DETP-speci c aptamer to detect the exposure history to organophosphates, by measuring their metabolite, although degradation of organophosphate parent compounds might occur.