Multitargeted molecular modelling of alginic acid modified with 4-aminophenol dopped with silver nanoparticles as a potent cytotoxic agent.

The activity of alginic acid as a cytotoxic agent was improved by structure modification using 4-aminophenol (4-AP) through condensation and polymerization processes. Then, silver nanoparticles were employed through doping to further enhance the cytotoxic activity of the modified polymer. The structure of the prepared materials was characterized by FT-IR, 1HNMR, UV spectroscopy, X-ray diffraction, and electron microscopy, and the thermal behavior of all synthesized materials was intensively studied. The cytotoxicity of the prepared compounds against cell lines of human hepatocellular (HepG-2) and lung (A-549) carcinomas was investigated. Alginic acid modified with 4-AP (Alg-4-AP3) showed the highest activity against HepG-2 and A-549 among all tested materials with IC50 values of 3.0 ± 0.19 µg/mL and 3.63 ± 0.23 µg/mL, respectively. Multitargeted molecular docking was employed to explore the binding modes of our compounds with the receptors EGFR, HER2, and VEGFR 2. The results revealed the inhibitory activity of our tested compounds against the proposed protein receptors, findings coincided with the in vitro results. In conclusion, the modification of alginic acid with 4-AP improved its cytotoxic activity against HepG-2 and A-549 cancer cells. In addition, doping the new materials with silver nanoparticles (AgNPs) further enhanced the cytotoxic activity.

Insights into the Synergistic Removal of Copper(II), Cadmium(II), and Chromium(III) Ions Using Modified Chitosan Based on Schiff Bases-g-poly(acrylonitrile).

Chitosan has received broad consideration as an adsorbent for all pollutants because of its low cost and great adsorption potential. However, its shortcomings, including sensitivity to pH, poor thermal stability, and poor mechanical strength, limit its use. The functional groups of chitosan can be modified to enhance its performance by the grafting technique and Schiff base modification. The grafting process used acrylonitrile (Ch-g-PAN) as a monomer and potassium persulfate as an initiator. After that, the modification via preparation of the Schiff base reaction using salicylaldehyde (Ch-g-Sch I) and P-anisaldehyde (Ch-g-Sch II) was carried out. The synthesized copolymers were detailed and characterized through several spectroscopic and microscopic techniques including infrared spectroscopy, scanning electron microscopy, and X-ray diffraction. In addition, Ch-g-Sch I and Ch-g-Sch II were applied in the removal of different metal ions such as Cu2+, Cd2+, and Cr3+. The maximum adsorption capacity of Ch-g-Sch I for Cd2+ was 183.7 mg g-1 in 24 h, while in the case of Ch-g-Sch II, the maximum adsorption capacity for Cd2+ was improved to 322.9 mg g-1 for the same time. Moreover, adsorption thermodynamic analysis displays that the all ion adsorption process was not random and the pseudo-second-order model fitted with experimental results. Finally, Ch-g-Sch I and Ch-g-Sch II were applied as designs for industrial wastewater treatment with significant efficiency.

Eco-friendly and biodegradable sodium alginate/quaternized chitosan hydrogel for controlled release of urea and its antimicrobial activity.

Hydrogels could be employed in agriculture for efficient management of water and controlled-release urea (CRU). This study aimed to synthesize a superabsorbent hydrogel for CRU by cross-linking sodium alginate (Alg) and N-(2-hydroxy-3-trimethyl ammonium) propyl chitosan chloride (HTACC). The hydrogel structure was characterized by various techniques, and the urea loading and releasing behaviors of the synthetic hydrogels were investigated. The results revealed that the maximum urea loading ranged between 107 and 200%, and that the urea loading kinetics fitted with Langmuir model followed by the Freundlich model. The urea release behavior reached equilibrium after 30 days and urea releasing kinetics fitted with the zero-order and Higuchi models. The synthesized hydrogels exerted significant antimicrobial activities and molecular docking showed their binding affinity toward glucosamine-6-phosphate synthase, ß-lactamase II, TraR binding site and nucleoside diphosphate kinase. In conclusion, these Alg/HTACC hydrogels showed swelling, urea release, and antimicrobial properties suitable to meet the plant requirements and produce economic and environmental benefits.

Synthesis and characterization of diphenylamine grafted onto sodium alginate for metal removal.

A novel grafting polymer was synthesized via grafting of diphenylamine (DPA) onto sodium alginate (NaAlg) as a new adsorbent for Cobalt (Co2+) from aqueous solutions. Optimization of sodium alginate grafted by diphenylamine (NaAlg-g-DPA) was addressed in the current study by several parameters including; initiator and monomer concentrations, contact time of polymerization, as well as polymerization temperature. In addition, the structural and chemical characteristics of NaAlg-g-DPA were explored using different modalities later. The results showed that sodium alginate grafted by diphenylamine (NaAlg-g-DPA) is suitable for adsorbent to removal Co2+ ion. The parameters for the adsorption of Co(II) ions by NaAlg-g-DPA were also determined. It was shown that the samples of NaAlg-g-DPA had given good correlation with Temkins isotherm model and their kinetics followed pseudo-second-order model. It was also observed that the adsorption capacity seemed to be dependent on pH value in solution which showed better results at basic pH. The findings from this research show that NaAlg-g-DPA has capability to remove Co (II) from aqueous solutions.

Synthesis, characterization and antimicrobial activity of Schiff bases modified chitosan-graft-poly(acrylonitrile).

Graft copolymerization of chitosan (Ch) with acrylonitrile (AN) prepared by free radical polymerization using potassium persulfate (PPS) as initiator. Optimization of Graft copolymerization of acrylonitrile on to chitosan was performed by studying the main parameters that affecting the grafting process such as initiator and monomer concentrations, reaction time and temperature of the polymerization process to study their influence on percent grafting (G%), grafting efficiency (GE%) and percent homopolymer (H%). Modification of grafted chitosan was done by Schiff's base derivatives using different aldehydes. They are characterized by FT-IR, X-ray diffraction, thermal analysis and scanning electron microscope. Their antibacterial activities against Streptococcus pneumonia (RCMB 010010), Staphylococcus aureus (RCMB 010028), as Gram-positive bacteria and Escherichia coli (RCMB 010052) as Gram-negative bacteria and the antifungal activity against Aspergillus fumigatus (RCMB 02568), Candida albicans (RCMB 05036) and Geotricum candidum (RCMB 05097) were examined using the diffusion agar technique. The obtained data proved that modified chitosan by grafting show better antimicrobial activities than Chitosan. Also Schiff base derivatives showed better antimicrobial activities than grafted chitosan.

Quaternized N-substituted carboxymethyl chitosan derivatives as antimicrobial agents.

Introduction of quaternary ammonium moieties into N-substituted carboxymethyl chitosan (N-substituted CMCh) derivatives enhances their biological activity. Several derivatives of CMCh having a variety of N-aryl substituents bearing either electron-donating or electron withdrawing groups have been synthesized by the reaction between amino group of CMCh with various aromatic aldehydes under acidic conditions, followed by reduction of the produced Schiff base derivatives with sodium cyanoborohydride. Each of the reduced derivatives was further quaternized using N-(3-chloro-2-hydroxy-propyl)trimethylammonium chloride (Quat-188). The resulting quaternized materials were characterized by FTIR and (1)H NMR spectroscopy. Their antibacterial activities against Streptococcus pneumoniae (S. pneumonia, RCMB 010010), Bacillis subtilis (B. subtilis, RCMB 010067), as Gram positive bacteria and against Escherichia coli (E. coli, RCMB 010052) as Gram negative bacteria and their antifungal activities against Aspergillus fumigatus (A. fumigates, RCMB 02568), Geotricum candidum (G. candidum, RCMB 05097), and Candida albicans (C. albicans, RCMB 05031) were examined using agar disk diffusion method. The results indicated that all the quaternized derivatives showed better antimicrobial activities than that of CMCh. These derivatives are highly potent against Gram positive bacteria compared to Gram negative bacteria. This is illustrated for example as the values of minimum inhibitory concentration (MIC) of Q4NO2-BzCMCh against B. subtilis and S. pneumonia were 6.25 and 12.5 µg/mL, respectively corresponded to 20.0 µg/mL against E. coli. The antimicrobial activity of quaternized N-aryl CMCh derivatives affected by not only the nature of the microorganisms but also by the nature, position and number of the substituent groups on the phenyl ring. Thus while the derivatives with groups of electron withdrawing nature show higher inhibition zone diameter and lower MIC values relative to that of those having electron-donating nature, the non-substituted derivative lies between these two extremes. Antibacterial activities of Q4NO2-BzCMCh, Q3Cl-BzCMCh and Q3Br-BzCMCh against E. coli are nearly equivalent to that of the standard drug Gentamycin. Q3Br-BzCMCh emerged almost equivalent antibacterial activity to Ampicillin against S. pneumonia.