Polypropylene Graft Poly(methyl methacrylate) Graft Poly(N-vinylimidazole) as a Smart Material for pH-Controlled Drug Delivery

Surface modification of polypropylene (PP) films was achieved using gamma-irradiation-induced grafting to provide an adequate surface capable of carrying glycopeptide antibiotics. The copolymer was obtained following a versatile two-step route; pristine PP was exposed to gamma rays and grafted with methyl methacrylate (MMA), and afterward, the film was grafted with N-vinylimidazole (NVI) by simultaneous irradiation. Characterization included Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), and physicochemical analysis of swelling and contact angle. The new material (PP-g-MMA)-g-NVI was loaded with vancomycin to quantify the release by UV-vis spectrophotometry at different pH. The surface of (PP-g-MMA)-g-NVI exhibited pH-responsiveness and moderate hydrophilicity, which are suitable properties for controlled drug release.

Polypropylene Graft Poly(Methyl Methacrylate) Graft Poly(N-Vinylimidazole) as a Smart Material for pH-Controlled Drug Delivery

Surface modification of polypropylene (PP) films is achieved using gamma-irradiation-induced grafting to proffer with antimicrobial activity. The copolymer was obtained through a versatile two-step route; pristine PP is exposed to gamma rays and grafted using methyl methacrylate (MMA), then N-vinylimidazole (NVI) is grafted onto the copolymer PP-g-MMA by simultaneous irradiation. The characterization included Fourier-Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscope (SEM), Thermogravimetric Analysis (TGA), X-ray Photoelectron Spectroscopy (XPS), and physicochemical analysis of swelling and contact angle. The copolymer (PP-g-MMA)-g-NVI was loaded with vancomycin, and the drug released was quantified by UV-vis spectrophotometry at different pH. The surface of (PP-g-MMA)-g-NVI exhibited pH-responsiveness and moderate hydrophilicity, suitable properties for controlled drug release.

RAFT-Mediated Radiation Grafting on Natural Fibers in Aqueous Emulsion

Using aqueous emulsion as the medium in radiation-induced graft polymerization (RIGP) offers an environment-friendly shift from organic solvents while increasing polymerization efficiency through known water radiolysis-based graft initiation. In the present paper, we further extend the applicability of RIGP in emulsion under the influence of reversible addition fragmentation chain transfer (RAFT) mechanisms. Emulsions prepared with Tween 20 showed good colloidal stability for several hours. Subjecting it to simultaneous irradiation with abaca fibers resulted in successful grafting, supported by gravimetric, IR, SEM, and TG analysis. A correlation was drawn between smaller monomer micelles and the enhancement of grafting driven by diffusion and surface area coverage. RAFT mechanisms were also conserved based on molecular weight evolution. RAFT-mediated RIGP in aqueous emulsion shows good potential as a versatile and green surface modification technique for natural fibers for various functional applications.

Manufacture of non-thrombogenic polymer surfaces by gamma irradiation to induce simultaneous grafting and heparinization of thin PVC films

Investigations regarding alternative methods for producing polymeric materials with hydrophilic properties have increased considerably. In this context, polymeric biomaterials with hemocompatible surface properties have been successfully obtained by grafting hydrophilic monomers onto commercial polymer films by simultaneous irradiation processes. In this study, simultaneous irradiation and grafting were used to produce a copolymer PVC-co-DMAEMA-co-heparin with hemocompatible surface properties. Characterization by FTIR of the graft copolymer indicates that the increase in monomer grafting levels inhibits the bonding sites to heparin. FTIR-PAS analyses of the graft copolymers showed that the highest graft levels were obtained for the irradiated samples containing 45% of monomer. Heparin, however, could only be detected in the irradiated samples containing 30% of DMAEMA. The analysis of the micrographs, on the other hand, showed that increasing the monomer concentration enhances surface roughness of the graft copolymers. Roughness however decreased with heparin addition. It was possible to verify that an excess of surface roughness of the graft copolymers inhibits anticoagulant properties of heparin, triggering thrombus formation. Platelet adhesion, on its turn, was not significantly affected by the presence of heparin when PVC-co-DMAEMA and PVC-co-DMAEMA-co-heparin, obtained from the systems containing 45% of monomer, are compared. The addition of heparin in the systems containing 30% of DMAEMA resulted in fewer thrombogenic surfaces.

Multivariate Optimization of Removing of Cobalt(II) with an Efficient Aminated-GMA Polypropylene Adsorbent by Induced-Grafted Polymerization under Simultaneous Gamma-Ray Irradiation

Nowadays, radiation grafting polymer adsorbents have been widely developed due to their advantages, such as low operating cost, high efficiency. In this research, glycidyl methacrylate monomers by simultaneous irradiation of gamma-ray with a dose of 20 kGy were grafted on polypropylene polymer fibers. The grafted polymer was then modified using different amino groups and tested for adsorption of cobalt ions in an aqueous solution. Finally, modified polymer adsorbent with the high efficiency for cobalt ions adsorption was synthesized and tested for further investigation. Different modes of cobalt ions adsorption were tested in other adsorption conditions, including adsorption contact time, pH, different amounts of adsorbent mass, and different concentrations of cobalt ions solution. The adsorbent structure was characterized with FT-IR, and SEM techniques and illustrated having an efficient grafting percentage and adsorption capability for cobalt removing by batch experiments. The optimum conditions were obtained by a central composite design as follows: adsorbent mass = 0.07 g, initial concentration = 40 mg/L, time = 182 min, and pH = 4.5 with ethylenediamine as a modified monomer and high amination percentage. The features such as inexpensive adsorbent, easy to prepare, high efficiency, and stability allow the radiated-induced grafted adsorbent to constitute one of promising materials for heavy metals remediation.

Photodynamic therapy for preinvasive vaginal cancer.

5592 Background: Photodynamic therapy (PDT) is an effective method for the treatment of various cancers resulting in apoptosis, autophagy and ischemic necrosis of irradiated tissues. The purpose of the study was to analyze the efficacy of PDT for pre-invasive vaginal cancer treatment. Methods: PDT results were studied in 20 patients aged 32-65 years with verified pre-invasive vaginal cancer. All patients received PDT with the Latus diode laser and Photolon or Photolan photosensitizers. The effect was evaluated with extended colposcopy. The criteria for efficiency included normalization of the colposcopic picture and the absence of atypical cells. The sizes of the irradiation fields varied from 1.5 to 2 cm, the number of fields - from 1 to 4, the power density - from 0.1 to 0.17 W/cm2, the light dose - from 40 to 100 J/cm2. The duration of a PDT session varied from 10 to 30 min, depending on the number of irradiation fields. The irradiation field necessarily included an area of normal tissue 3-5 mm surrounding the lesion. 4 to 6 sessions were required to restore the normal layer of stratified squamous epithelium. The antitumor efficacy of PDT was evaluated based on the results of visual observation of changes in the area of the treated pathological foci and information on the presence or absence of clinical symptoms of the disease 1 and 3 months after the treatment (WHO criteria). Results: Complete regression was registered in 100% of patients after 3 months. Repeated courses of PDT were required in cases with a wide spread of pathological foci and the impossibility of their simultaneous irradiation. At follow-up after 1 month, 3 of 20 patients (15%) showed local foci of atypical changes in the epithelium managed with repeated PDT courses. In 6 months, stable remission of the disease clinical symptoms in the treated pathological foci was registered. The results of the cytological study performed 3 months after PDT were normal in 100% patients; no negative changes were registered 6 and 12 months after PDT. Conclusions: The results of PDT in the treatment of patients with pre-invasive vaginal cancer demonstrated its high therapeutic efficacy and a minimal number of adverse reactions, which allows recommending PDT in the treatment of pre-invasive vaginal cancer.

A Gel Polymer Electrolyte Reinforced Membrane for Lithium-Ion Batteries via the Simultaneous-Irradiation of the Electron Beam

In this research, a series of innovative and stable cross-linked gel polymer reinforced membranes (GPRMs), were successfully prepared and investigated for application in lithium-ion batteries. Herein, a gel directly within the commercial polyethylene (PE) separator is supported via electron-beam simultaneous irradiation cross-linking of commercial liquid electrolyte and poly(ethylene glycol) methacrylate (PEGMA) oligomers. The physical and electrochemical properties of the GPRMs were characterized by SEM, TEM, mechanical durability, heating shrinkage, and ion conductivity, etc. The GPRMs demonstrated excellent mechanical durability and high ion conductivity compared with traditional PE membranes. Moreover, coin-typed cells were assembled and cycle performance was also studied compared with same-typed cells with commercial PE membrane and liquid electrolyte. As a result, the coin-typed cells using GPRMs also showed a relatively good efficiency on the 50th cycles at a high 1.0 C-rate. These GPRMs with excellent properties present a very promising material for utilization in high-performance lithium-ion batteries with improved safety and reliability.