Novel Synthesis, Characterization and Amoxicillin Release Study of pH-Sensitive Nanosilica/Poly(acrylic acid) Macroporous Hydrogel with High Swelling

The effect of SiO2 nanoparticles on the formation of PAA (poly acrylic acid) gel structure was investigated with seeded emulsion polymerization method used to prepare SiO2/PAA nanoparticles. The morphologies of the nanocomposite nanoparticles were studied by transmission electron microscopy (TEM). Fourier-transform infrared (FTIR) spectroscopy results indicated that the PAA was chemically bonded to the surface of the SiO2 nanoparticles. Additionally, the resulting morphology of the nanocomposite nanoparticles confirmed the co-crosslinking role of the SiO2 nanoparticles in the formation of the 3D structure and hydrogel of PAA. SiO2/PAA nanocomposite hydrogels were synthesized by in situ solution polymerization with and without toluene. The morphology studies by field emission scanning electron microscopy (FESEM) showed that when the toluene was used as a pore forming agent in the polymerization process, a macroporous hydrogel structure was achieved. The pH-sensitive swelling behaviors of the nanocomposite hydrogels showed that the formation of pores in the gels structure was a dominant factor on the water absorption capacity. In the current research the absorption capacity was changed from about 500 to 4000 g water/g dry hydrogel. Finally, the macroporous nanocomposite hydrogel sample was tested as an amoxicillin release system in buffer solutions with pHs of 3, 7.2, and 9 at 37 °C. The results showed that the percentage cumulative release of amoxicillin from the hydrogels was higher in neutral and basic mediums than in the acidic medium and the amoxicillin release rate was decreased with increasing pH. Additionally, the release results were very similar to swelling results and hence amoxicillin release was a swelling controlled-release system.

Preparation and application of poly (hydroxyl ethyl methacrylate) nanocomposite hydrogels containing iron oxide nanoparticles as wound dressing

In recent years, polymeric hydrogels are widespread in the field of biological materials such as wound dressing and wound care. In this work, we report for the first time the preparation and application of pHEMA nanocomposite hydrogels containing iron oxide nanoparticles as wound dressings. For this purpose, nanocomposite hydrogels based on poly (hydroxyl ethyl methacrylate) (pHEMA) and various amounts of 5, 10, and 15 wt% iron oxide nanoparticles were successfully prepared via radical polymerization. The structure and morphology of nanocomposite hydrogels were determined by Fourier transform infrared spectroscopy (FTIR) and field emission scanning electron microscope (FE-SEM), respectively. The results of gel fraction and the degree of swelling of hydrogels demonstrated that the gel percentage of pHEMA increased, and the degree of swelling decreased with increasing the percentage of nanoparticles. The WVRT and the porosity of hydrogels decreased by increasing the quantity of nanoparticles and were suitable for wound dressing applications. The effect of iron oxide nanoparticles on the mechanical properties of nanocomposite hydrogels was also studied using compression test and hardness shore A durometer. The results indicated that the compression strength, modulus, strain, and hardness are steadily increasing compared to pure hydrogel by adding nanoparticles. The maximum increase was obtained for a hydrogel sample with 15 wt% iron oxide nanoparticles. Antibacterial properties and biocompatibility were determined by the disk-diffusion and MTT assay methods, respectively. Based on the results, nanocomposite hydrogels exhibited higher percentages of cell survival and better antibacterial properties compared to pure pHEMA.

Adsorption and Sustained Delivery of Small Molecules from Nanosilicate Hydrogel Composites

Two-dimensional nanosilicate particles (NS) have shown promise for the prolonged release of small-molecule therapeutics while minimizing burst release. When incorporated in a hydrogel, the high surface area and charge of NS enable electrostatic adsorption and/or intercalation of therapeutics, providing a lever to localize and control release. However, little is known about the physio-chemical interplay between the hydrogel, NS, and encapsulated small molecules. Here, we fabricated polyethylene glycol (PEG)-NS hydrogels for the release of model small molecules such as acridine orange (AO). We then elucidated the effect of NS concentration, NS/AO incubation time, and the ability of NS to freely associate with AO on hydrogel properties and AO release profiles. Overall, NS incorporation increased the hydrogel stiffness and decreased swelling and mesh size. When individual NS particles were embedded within the hydrogel, a 70-fold decrease in AO release was observed compared to PEG-only hydrogels, due to adsorption of AO onto NS surfaces. When NS was pre-incubated and complexed with AO prior to hydrogel encapsulation, a >9000-fold decrease in AO release was observed due to intercalation of AO between NS layers. Similar results were observed for other small molecules. Our results show the potential for use of these nanocomposite hydrogels for the tunable, long-term release of small molecules.

PHYSICO-CHEMICAL PROPERTIES OF A NANOCOMPOSITE HYDROGEL COATING ON A TEXTILE CARRIER FOR THE WOUND TREATMENT

Нанотехнологии с использованием биополимеров находят широкое применение в биомедицинских приложениях. В данной работе разработаны нанокомпозитные гидрогели на основе природных (хитозан, карбоксиметилцеллюлоза) и синтетических (поливиниловый спирт) полимеров с наночастицами серебра для нанесения на текстильный носитель. В качестве сшивающих реагентов при создании гидрогелей использовали диальдегид карбоксиметилцеллюлозы и борную кислоту. Были определены физико-химические свойства (сорбционная способность при одностороннем контакте с модельной средой, степень набухания, паропроницаемость, капиллярность) гидрогелевых покрытий на текстильном носителе, и кинетика выхода лекарственных веществ (лидокаин, диоксидин), включенных в состав гидрогелей. Показано, что материалы с двухслойным покрытием характеризуются более высокими сорбционными свойствами по отношению к физиологическому раствору и более длительным выходом лекарственных средств, чем материалы с однослойным покрытием. Выход лекарственных веществ из двухслойных покрытий происходит в два этапа с максимальным высвобождением в течение двух суток. Полученные текстильные материалы с пленочным нанокомпозитным гидрогелевым покрытием могут найти применение в качестве перевязочных средств при лечении ран. Nanotechnologies using biopolymers are widely used in biomedical applications. In this work, nanocomposite hydrogels based on natural (chitosan, carboxymethylcellulose) and synthetic (polyvinyl alcohol) polymers with silver nanoparticles for application to a textile carrier have been developed. Carboxymethylcellulose dialdehyde and boric acid were used as crosslinking reagents in the creation of hydrogels. Physicochemical properties (sorption capacity in unilateral contact with the model medium, degree of swelling, vapor permeability, capillarity) of hydrogel coatings on a textile carrier, and the kinetics of the drugs release (lidocaine, dioxidine) included in the hydrogels were determined. It is shown that materials with a two-layer coating are characterized by higher sorption properties relative to saline and a longer release of drugs than materials with a single-layer coating. The release of drugs from the two-layer coatings occurs in two stages with a maximum release within two days. The obtained textile materials with a film nanocomposite hydrogel coating can be used as dressings in the treatment of wounds.

MB Dye Adsorption Behavior on Poly (N cyclohexylacrylamide-co-Acrylamide/Maleicacid)/ OMMT Nanocomposite Hydrogels

A series of poly (N-cyclohexylacrylamide-co-Acrylamide/Maleic acid) /OMMT nanocomposite hydrogels (NC) were prepared from free-radical copolymerization in water/methanol medium using ammonium persulfate (APS) as a free radical initiator and N,N’- methylene-bis-acryl amide(MBA) as the cross-linker at 60˚C. The nanocomposite hydrogels were synthesized via in situ polymerization using organo modified MMT (O-MMT) nano clay. The optimum swelling of nanocomposite superabsorbents was achieved at 0.150g of OMMT nanoclay. The synthesized nanocomposites were characterized by FTIR, SEM, XRD and TGA techniques. Swelling and diffusion parameters in water and dye solution were calculated. The effect of two cationic salt solutions on the swelling was studied. The hydrogel nanocomposites showed up to 99.9% removal efficiency towards methylene blue dye adsorption study.