This study was focused on the preparation of an environmentally friendly nanocellulose based hydrogel in the form of pads. Hydrogels are hydrophilic three dimensional network with crosslinks, which swells in water but don’ t dissolve. In this research nanofibrillated cellulose and Hydroxyethyl cellulose with different ratio (1: 1, 2: 1, 3: 1) were used to make hydrogel. Also, citric acid which has a significant advantage over other crosslinking agents in terms of toxicity and price, has been used in different amounts of 10% and 20% by weight to crosslink. In order to find optimal hydrogel preparation conditions, FTIR analysis, FESEM, time dependent swelling measurement and evaluating the thermal and rheological properties were performed. Samples with a lower ratio of nanocellulose to hydroxyethyl cellulose were found to be inappropriate due to the loss of their apparent integrity in the swelling measurement. According to FTIR results, cross-linking were performed only in samples with the highest ratio of nanocellulose to hydroxyethyl cellulose in different amounts of citric acid. Therefore, the hydrogels' characteristics were mainly influenced by the ratio of nanocellulose to hydroxyethyl cellulose and the amount of citric acid had less effect on these properties. These two successful final samples showed acceptable properties in other evaluated properties and led to the selection of optimal reactive ratios for the preparation of hydrogels for use in various industries, including the pharmaceutical industry.

An antibacterial wound dressing hydrogel was synthesized from biopolymers and a semiconductor nanomaterial by gamma irradiation, and applied in a simulated environment. Polyvinyl alcohol (PVA)/agar hydrogel was chosen due to its biocompatibility and good swelling to absorb wound exudates and make a moist environment to accelerate the wound healing process. Zinc oxide nanoparticles were synthesized and combined with the hydrogel due to their antibacterial activity as a wound dressing aid and the hydrophilic nature to enhance swelling capacity by facilitating water flow in the hydrogel. Hydrogel samples based on PVA/agar containing low amounts of zinc oxide nanoparticles were prepared by gamma irradiation to meet all the requirements of a wound dressing. Water absorption, swelling behavior and pH sensitivity were studied and showed an excellent water swelling capacity. Scanning electron microscopy (SEM) and UV–, Vis spectroscopy analyses were employed, where dispersion state of nanoparticles played a key role. Antibacterial activity mechanisms and the resistance to gram-positive bacteria were tested by the disk diffusion method, and the developed hydrogel revealed resistance against gram-positive bacteria. A cone and plate rheometer was used to capture the rheological response of hydrogel. Reduction in viscosity and elastic modulus was due to increasing the amount of zinc oxide nanoparticles. Analyses on mechanical properties approved that hydrogels had enough strength for wound dressing to resist tear once stretched.