Fully bio-based supramolecular gel based on cellulose nanowhisker gallate by cyclodextrin host-guest chemistry.

Nowadays, supramolecular hydrogels have gained special importance and development of versatile approaches for their preparation as well as their new facile characterization strategies has elicited tremendous scientific interest. Herein, we demonstrate that modified cellulose nanowhisker with gallic acid pendant groups (CNW-GA) could effectively bind with CNW grafted with ß-Cyclodextrin (CNW-g-ß-CD) through HG interaction to form fully biocompatible and low-cost supramolecular hydrogel. Also, we reported an easy and efficient colorimetric characterization method for confirming HG complexation using naked eye. The possibility of this characterization strategy evaluated both experimentally and theoretically using DFT method. Also, phenolphthalein (PP) was used for visual detection of HG complexation. Interestingly, PP undergoes a rearrangement in its structure in presence of CNW-g-ß-CD because of HG complexation that turns the purple molecule into a colorless compound in alkaline condition. Addition of CNW-GA to the resulting colorless solution turned the color to purple again which easily confirmed HG formation.

Fabrication of new generation of co-delivery systems based on graphene-g-cyclodextrin/chitosan nanofiber.

Although many techniques have been devoted to promote therapeutic purposes of drug carrier systems, however, there are still many challenges in this area. Here, we designed co-loaded delivery systems, composed of curcumin loaded cyclodextrin-graphene oxide core (Cur@CD-GO) and gallic acid loaded chitosan shell nanofibers (Cur-Ga NF), which can promote the therapeutic efficiency of drugs. The synthesized nanofibres were fabricated by electrospinning technique with the coaxial system. Results showed that co-loaded delivery systems (Cur-Ga NF) provide better performance over single drug-loaded NFs (Cur@CD-GO). It was demonstrated that the nanofibers were successfully prepared, and the drugs in the core and sell of nanofibers were released in a controlled and sustained manner. The produced Cur-Ga NF, providing improved anti-cancer activity, antimicrobial activity, antioxidant activity and anti-inflammatory outcome as compared to single drug-loaded NFs. Our investigations showed that such co-delivery fiber systems could be employed as a promising nanocarrier for therapeutic applications.

Adsorption Mechanism of Congo Red on Mg-Al-layered Double Hydroxide Nanocompound.

In this work, congo red (CR) was removed by applying carbonate intercalated Mg-Al-layered double hydroxide (Mg-Al-LDH) nanocompound as an adsorbent. Batch adsorption experiments performed under various temperatures, ionic strengths, initial CR concentrations, alkalinities and shaking rates. The maximum adsorption capacities of Mg-Al-LDH for CR were 100, 105 and 86.8 mg g-1 at 308, 318 and 328 K, respectively. Adsorption sites of Mg-Al-LDH for CR were -OH groups attached to Al atoms of adsorbent layers. Adsorption isotherms of the process were studied by the ARIAN model and analysis of obtained data showed that there were two kinds of adsorption sites on the surface of Mg-Al-LDH. Results of instrumental analysis showed that these adsorption sites were -OH groups located on the surface of mesopores and micropores of adsorbent and were named MP and 003 sites, respectively. The kinetic data were studied by the KASRA model and ISO and intraparticle diffusion (pore-diffusion) equations which showed that CR molecules were adsorbed at first on the MP sites. Also, during the adsorption of CR on MP sites the interaction of CR with adsorbent surface was rate-controlling step. Furthermore, during CR adsorption on 003 sites, adsorption kinetics was diffusion-controlled.

Bioconjugated graphene oxide hydrogel as an effective adsorbent for cationic dyes removal.

In this study, graphene oxide - cellulose nanowhiskers nanocomposite hydrogel was easily synthesized through covalent functionalization of cellulose nanowhiskers with graphene oxide via a facile approach. The nitrene chemistry applied for covalent functionalization of graphene oxide sheets. The surface morphology and chemical structure of the nanocomposite hydrogel were characterized by FTIR, TGA, Raman, XRD, elemental analysis and SEM. The UV/Visible absorption spectrum revealed that the obtained porous nanocomposite hydrogel can efficiently remove cationic dyes such as methylene blue (MB) and Rhodamine B (RhB) from wastewater with high absorption power. The adsorption process showed that 100% of MB and 90% of RhB have been removed and the equilibrium state has been reached in 15min for low concentration solutions in accordance with the pseudo-second-order model. Moreover, the sample exhibited stable performance after being used several times. High adsorption capacity and easy recovery are the efficient factors making these materials as good adsorbent for water pollutants and wastewater treatment.

Dendronization of cellulose nanowhisker with cationic hyperbranched dendritic polyamidoamine.

Polyamidoamine (PAMAM) dendrimers with active amino group up to the third generation were grafted onto the surface of cellulose nanocrystals (CNCs) by a divergent method. Cellulose nanowhiskers (CNW) are gaining interest as a "green" nanomaterial with exceptional chemical and mechanical properties for high-performance nanocomposite materials. Cellulose nanowhiskers are usually isolated from cotton by sulfuric acid hydrolysis and hydrochloric acid hydrolysis. The grafting of PAMAM dendrimer on CNW surface was monitored using FTIR, (1)H NMR, DLS and AFM. The results of FTIR and (1)H NMR confirmed the formation of PAMAM on the CNW. AFM images indicated the PAMAM synthesis on CNW through the nano-scale structures of macromolecules. The Zeta-potential value of polymer was found to be around +25 mV, and according to the collected data, the effective diameter of the CNW-g-PAMAM particles measured through DLS technique was found to be 73 nm.