Zinc/aluminum-layered double hydroxide-gallic acid doped carboxymethyl cellulose nanocomposite films for wound healing.

Effective loading and delivering the wound healing-based materials to the wound site and area with an optimum concentration and limited cytotoxicity are essential for a complete and fast healing process. Here, we have designed Zn/Al-LDH nanoparticles-loaded CMC films for encapsulation and delivery of gallic acid (GA) in order to develop an effective and efficient wound-healing scaffold. The physicochemical properties of the prepared Zn/Al-LDH nanohybrids were thoroughly characterized by several characterization techniques, such as FESEM, Hi-TEM, FTIR, and XRD techniques. The thermal properties of the scaffolds were evaluated by DSC and TGA analysis. The release profiles of GA from fabricated films were studied over 8 h by UV-vis spectroscopy. In vitro drug release studies in PBS solutions with pH 7.4 showed a mono-phasic profile in which the liberation of the drug mainly occurred by scaffold erosion and increased by increasing the experiment period. The in vitro antibacterial activity of Zn/Al-LDH-GA-loaded CMC films was assessed by disk diffusion and cell viability contact tests. The results showed the desired antibacterial activity against Staphylococcus aureus and Escherichia coli bacteria. Incorporating GA within CMC and CMC-Zn/Al-LDH films rereleased good cytocompatibility at the studied incubation time and different concentrations toward human normal HFF cell line than the free drug. The results of the present study indicated that the Zn/Al-LDH and Zn/Al-LDH-GA-loaded CMC have promising wound healing features to further develop a better future for clinical remedy of the different non-healing and hard-to-heal wounds.

A practical method for rehabilitation of stormwater collecting system by node flooding detection and regional hydraulic redesign: a case study of eastern Tehran metropolis.

This study investigates the effect of structural modification actions on the existing stormwater collecting system in Eastern Tehran to increase the hydraulic capacity and create suitable conditions for the passage of runoff in the critical points of the canal. First, the hydraulic conditions within the stormwater collecting system were simulated using the Stormwater Management Model (SWMM) model before/after the modification to investigate the rehabilitation results. Three critical locations along the main canal were recognized as the most vulnerable points. Then, based on field visits and brainstorming sessions, rehabilitation methods were presented, and three practical solutions, including canal deepening, canal widening, and their combination, were investigated for each. Then, local investigating based on the rehabilitation alternatives for each critical location was conducted using the HEC-RAS. Finally, the SWMM model was used again to evaluate the overall operational performance of the stormwater collecting system after the rehabilitation. The results revealed that it is necessary to implement two alternatives of deepening and widening to provide adequate transmission runoff capacity during rainfalls with various return periods. More specifically, the localized redesign of the eastern flood diversion canal had an acceptable improvement in reducing flooding problems so that for floods with a return period of 10 years, the number of node flooding dropped from 4 to 0, inundated areas from 17% to 0, and the overflow volume from (10-45) to 0. Moreover, the proposed local rehabilitation reduced the overflow volume from (30-65), (43-74), and (70-92) in the status quo to (4-12), (11-27), and (24-36) for rainfall with 25, 50, and 100-year return periods.

Facile synthesis of chitosan/ZnO bio-nanocomposite hydrogel beads as drug delivery systems.

ZnO nanoparticles were synthesized in situ during the formation of physically cross-linked chitosan hydrogel beads using sodium tripolyphosphate as the cross-linker. The aim of the study was to investigate whether these nanocomposite beads have the potential to be used in drug delivery applications. The formation of ZnO nanoparticles (ZnONPs) in the hydrogels was confirmed by X-ray diffraction and scanning electron microscopy studies. SEM micrographs revealed the formation of ZnONPs with size range of 10-25 nm within the hydrogel matrix. Furthermore, the swelling and drug release properties of the beads were studied. The prepared nanocomposite hydrogels showed a pH sensitive swelling behavior. The ZnO nanocomposite hydrogels have rather higher swelling ratio in different aqueous solutions in comparison with neat hydrogel. In vitro drug release test was carried out to prove the effectiveness of this novel type of nanocomposite beads as a controlled drug delivery system. A prolonged and more controlled drug releases were observed for ZnONPs containing chitosan beads, which increased by the increase in ZnONPs content.

Preparation and properties of carboxymethyl cellulose/layered double hydroxide bionanocomposite films.

Solution casting method was employed for preparing of carboxymethyl cellulose/layered double hydroxide (CMC-LDH) bionanocomposite films with LDH content ranged from 0 to 8 wt%. The synthesized nanocomposite films were characterized using FTIR, XRD, TEM and SEM analytical methods. XRD and TEM analysis revealed a partially exfoliated structure for nanocomposites with LDH content up to 3 wt%. However, for LDH contents higher than 3 wt%, nanocomposites formed an intercalated structure. Incorporation of LDH significantly decreased water vapor permeability (WVP) of the bionanocomposite films up to 37%. Addition of the LDHs into the CMC matrix is accompanied by a decrease in the film transparency. Mechanical properties of CMC-based films were improved significantly by addition of LDH particles. CMC-LDH nanocomposite film with 3 wt% LDH showed a 148 and 143% increase in the tensile strength and tensile modulus, as well as a 62% decrease in elongation in comparison with the pure CMC film.