Preparation of colloidal nanoparticles PVA-PHEMA from hydrolysis of copolymers of PVAc-PHEMA as anticancer drug carriers

The novel pH-responsive polymer nanoparticles have been widely used for drug delivery and cancer therapy. The pH-sensitive nanoparticles include chemical structures that can accept or donate protons in response to an environmental pH change. Polybases which mostly contain alkaline groups such as amines and hydroxy, accept protons at low pH and are neutral at higher pH values. This study aimed to prepare pH-sensitive colloidal amphiphilic poly(vinyl alcohol-2-hydroxyethyl methacrylate) (PVA-PHEMA) copolymers in cancer therapy applications. For this purpose, poly(vinyl acetate-2-hydroxyethyl methacrylate) (PVAc-PHEMA) copolymer nanoparticles were synthesized in different polymerization medium fractions from water and methanol and different monomer feed concentration. Then acetate groups were hydrolyzed, and the PHEMA-PVA nanoparticles were synthesized. The nanoparticles were further characterized using dynamic light scattering, Fourier transform infrared spectroscopy, scanning electron microscopy, and thermogravimetric analysis to identify the structural and morphological changes. The Methotrexate (MTX) was loaded into the nanoparticles, and drug release kinetics were evaluated. The results confirmed that PHEMA-PVA copolymeric nanoparticles could be favorably used in cancer therapy.

Analytical Parameters of a Novel Glucose Biosensor Based on Grafted PFM as a Covalent Immobilization Technique

Bioanalytical methods, in particular electrochemical biosensors, are increasingly used in different industrial sectors due to their simplicity, low cost, and fast response. However, to be able to reliably use this type of device, it is necessary to undertake in-depth evaluation of their fundamental analytical parameters. In this work, analytical parameters of an amperometric biosensor based on covalent immobilization of glucose oxidase (GOx) were evaluated. GOx was immobilized using plasma-grafted pentafluorophenyl methacrylate (pgPFM) as an anchor onto a tailored HEMA-co-EGDA hydrogel that coats a titanium dioxide nanotubes array (TiO2NTAs). Finally, chitosan was used to protect the enzyme molecules. The biosensor offered outstanding analytical parameters: repeatability (RSD = 1.7%), reproducibility (RSD = 1.3%), accuracy (deviation = 4.8%), and robustness (RSD = 2.4%). In addition, the Ti/TiO2NTAs/ppHEMA-co-EGDA/pgPFM/GOx/Chitosan biosensor showed good long-term stability; after 20 days, it retained 89% of its initial sensitivity. Finally, glucose concentrations of different food samples were measured and compared using an official standard method (HPLC). Deviation was lower than 10% in all measured samples. Therefore, the developed biosensor can be considered to be a reliable analytical tool for quantification measurements.