Hertzian elasticity and triggered swelling kinetics of poly(amino ester)-based gel beads with controlled hydrophilicity and functionality: A mild and convenient synthesis via dropwise freezing into cryogenic liquid

Leveraging the Dielectric Barrier Discharge Plasma Process to Create Regenerative Biocidal ePTFE Membranes

The utilization of dielectric barrier discharge (DBD) plasma treatment for modifying substrate surfaces constitutes an easy and simple approach with a potential for diverse applications. This technique was used to modify the surface of a commercial porous expanded poly(tetrafluoroethylene) (ePTFE) film with either dimethylaminoethyl methacrylate (DMAEMA) or (trimethylamino)ethyl methacrylate chloride (TMAEMA) monomers, aiming to obtain antibacterial ePTFE. Physicochemical analyses of the membranes revealed that DBD successfully enhanced the surface energy and surface charge of the membranes while maintaining high porosity (>75%) and large pore size (>1.0 μm). Evaluation of the bacteria killing-releasing (K-R) function revealed that both DMAEMA and TMAEMA endowed ePTFE with the ability to kill Escherichia coli bacteria. However, only TMAEMA-grafted ePTFE allowed for the release of dead bacteria from the surface upon washing with sodium hexametaphosphate (SHMP) saline solution, owing to its cationic charge derived from the quaternary amine. Washing with SHMP disturbed the electrostatic force between the polymer brushes and dead bacteria, which caused the release of the dead bacteria. Lastly, dead-end bacteria filtration showed that the TMAEMA-grafted ePTFE was able to kill 99.78% of the bacteria, while approximately 61.55% of bacteria were killed upon contact. The present findings support the feasibility of using DBD plasma treatment for designing surfaces that target bacteria and aid in the containment of disease-causing pathogens.

Design of Environmentally Friendly Ca-Alginate Beads for Self-Healing Cement-Based Materials

Ca-alginate beads have strong hygroscopicity, which have been used for the self-healing and internal curing of cement-based materials. However, ca-alginate beads in cement will chelate with calcium ions, which decreases the swelling rate of ca-alginate beads in the healing environment and is detrimental to the self-healing of cement-based materials. In this paper, the mechanism and steps for preparing ca-alginate beads with a lower ability to chelate with calcium ions were proposed based on protonation theory. In addition, the molecular structure and the swelling rates in cement filtrate and healing environment of ca-alginate beads prepared by the proposed method were characterized. The results showed that the ca-alginate beads prepared by the proposed method had higher molecular density and a lower ability to chelate with calcium ions. The swelling rate in the healing environment is not decreased. Furthermore, the equilibrium swelling rate in cement filtrate can satisfy the need for internal curing of cement-based materials.

Gel Properties of Blue Round Scad (Decapterus Maruadsi) Mince as Influenced by the Addition of Egg White Powder

The use of egg white powder (EWP) to enhance the physicochemical properties, molecular structure, and thermal stability of Decapterus maruadsi mince gels was investigated. The thermal stability was analyzed by adding spray-dried EWP (0%, 0.2%, 0.4%, 0.6%, 0.8%, 1%) to the mince, and mince gels were prepared to study the changes in their fracture constant, water distribution, microstructure and protein conformation of mince gels. In addition, the stress-strain curve of the EWP-mince gel was measured to obtain its compressive modulus (E). The formation of the mince gel was promoted by EWP, and the whiteness, fracture constant, water-holding capacity, and immobilized water were all enhanced. At 0.8% addition of EWP, the fracture constant increased from 176.715±2.463 N/m to 348.631±3.144 N/m (p<0.05), which was a nearly twofold improvement. Additionally, the water-holding capacity increased from 75.21% to 79.99%, and the percentage of immobilized water increased from 94.03% to 94.91%. The EWP-mince gel network structure was the most uniform and dense, and there were increases in hydrogen bonds, disulfide bonds, β-sheets, and β-turns in mince gels, as well as the storage modulus (G') and enthalpy (ΔH). In contrast to the control group, the relative content of α-helixes decreased from 53.34% to 37.09% and transformed into other secondary structures, and the bulk water and cooking loss also decreased to 2.41% and 8.51%, respectively. Consequently, EWP effectively improved the quality of mince products, and the effect was most apparent when 0.8% was added.

Antibacterial Amphiphilic Copolymers of Dimethylamino Ethyl Methacrylate and Methyl Methacrylate to Control Biofilm Adhesion for Antifouling Applications

Amphiphilic copolymers are recognized as important biomaterials and used as antibacterial agents due to their effective inhibition of bacterial growth. In current study, the amphiphilic copolymers of P(DMAEMA-co-MMA) were synthesized using free radical polymerization by varying the concentrations of hydrophilic monomer 2-dimethylamino ethylmethacrylate (DMAEMA) and hydrophobic monomer methyl methacrylate (MMA) having PDI value of 1.65-1.93. The DMAEMA monomer, through ternary amine with antibacterial property optimized copolymers, P(DMAEMA-co-MMA), compositions to control biofilm adhesion. Antibacterial activity of synthesized copolymers was elucidated against Gram-positive Staphylococcus aureus (ATCC 6538) and Gram-negative Escherchia coli (ATCC 8739) by disk diffusion method, and zones of inhibition were measured. The desired composition that was PDM1 copolymer had shown good zones of inhibition i.e., 19 ± 0.33 mm and 20 ± 0.33 mm for E. coli and S. aureus respectively. The PDM1 and PDM2 have exhibited significant control over bacterial biofilm adhesion as tested by six well plate method. SEM study of bacterial biofilm formation has illustrated that these copolymers act in a similar fashion like cationic biocide. These compositions viz. PDM1 and PDM2, may be useful in development of bioreactors, sensors, surgical equipment and drug delivery devices.