Growth of Silver Nanoparticles into Reducing-End Carbohydrate-Based Supramolecular Hydrogels for Antimicrobial Applications.

Hydrogels with antibacterial activities have the potential for many biomedical applications, such as wound healing, because of their capacity to maintain a moist environment and prevent infections. In this work, an ultrasound-induced supramolecular hydrogel consisting of easily accessible reducing-end-free glucosaminylbarbiturate-based hydrogelators that serve the fabrication of silver nanoparticles (AgNPs), excluding the addition of any external reducing or stabilizing agents, has been developed. The innovative synthetic approach relied on the use of -disubstituted barbituric acid derivatives as a versatile chemical platform that site-selectively reacted with the amino function of glucosamine.

Sustainable energy and waste management: How to transform plastic waste into carbon nanostructures for electrochemical supercapacitors.

Plastic waste consumption increases exponentially every year, mainly in the last three years due to the COVID-19 pandemic. The rapid growth of plastic products has exceeded the world's capacity to deal with this type of trash. Thus, it has become a substantial environmental concern in modern society.

Magnetic-responsive polysaccharide hydrogels as smart biomaterials: Synthesis, properties, and biomedical applications.

This review reports recent advances in polysaccharide-based magnetic hydrogels as smart platforms for different biomedical applications. These hydrogels have proved to be excellent, viable, eco-friendly alternative materials for the biomedical field due to their biocompatibility, biodegradability, and possibility of controlling delivery processes via modulation of the remote magnetic field. We first present their main synthesis methods and compare their advantages and disadvantages.

Development of composite hydrogel based on hydroxyapatite mineralization over pectin reinforced with cellulose nanocrystal.

Hydrogels based on pectin and cellulose nanocrystals (CNC) were used in our study to nucleation and growth of hydroxyapatite (HAp) by the biomimetic method. In this study, we evaluated the direct impact of the different percentages of CNC on pectin hydrogel and the influence of HAp obtained through two methods. CNC were obtained from HCl hydrolysis following chemical functionalization through vinyl groups.

Enhancing Near-Infrared Photothermal Efficiency of Biocompatible Flame-Synthesized Carbon Nano-Onions with Metal Dopants and Silica Coating.

As an alternative to eliminating cancer cells with minimal impacts on the nearby tissues, biocompatible nanoparticles based on silica-coated carbon nano-onions, with outstanding photothermal efficiency, are presented. Metal-doped carbon nano-onion@SiO materials are produced using flame synthesis. Metal complexes are injected in the flame to tune the carbon organization levels, which results in materials with excellent photostability and total photothermal conversion efficiency, regarding the incident light input, as higher as 48% for 785 nm laser.

Two-dimensional thermoresponsive sub-microporous substrate for accelerated cell tissue growth and facile detachment.

Thermoresponsive sub-microporous films having a lower critical solution temperature (LCST), promptly obtained by using the breath figure method, were applied to tissue engineering. These sub-microporous films, sized 100-400 nm, were prepared by blending poly(N-isopropylacrylamide) (PNIPAAm) with polystyrene (PS), in addition to applying the dynamic breath figure (BF) method. The thermoresponsive blends were prepared with polyethylene terephthalate (PET) substrate by using a spin coater; the pore size was modulated according to the spin speed.

Biomimetic nanocomposite based on hydroxyapatite mineralization over chemically modified cellulose nanowhiskers: An active platform for osteoblast proliferation.

Functionalized-cellulose nanowhiskers (CNWs) were obtained and used to improve hydroxyapatite (HAp) growth by the biomimetic method. CNWs were obtained through HCl hydrolysis and then submitted to chemical functionalization with carboxylate or amine groups that can induce selective HAp mineralization efficiently. Functionalized-CNWs were tested against HAp growth through the biomimetic method using a simulated body fluid (SBF) as a medium during 14 and 28 days of mineralization.

Water Droplet Self-Assembly to Au Nanoporous Films with Special Light Trapping and Surface Electromagnetic Field Enhancement.

Gold nano "breath figure" films are for the first time reported and their function as ideal systems for plasmonics demonstrated. Metal nano-breath figure substrates are metal thin films containing nanohole arrays supported on a solid substrate. Au nanohole arrays are prepared from the dynamic breath figure phenomenon, in which the pore formation is controlled to provide holes smaller than 100 nm.

Cellulose nanowhiskers decorated with silver nanoparticles as an additive to antibacterial polymers membranes fabricated by electrospinning.

Antimicrobial films based on distinct polymer matrices, poly (vinyl alcohol) (PVA) or poly (N-isopropylacrylamide) (PNIPAAm), and silver nanoparticles (AgNPs) immobilized onto cellulose nanowhiskers (CWs) were successfully prepared by either casting or electrospinning. CWs were first functionalized with carboxylate groups (labeled as CWSAc) and later they were immersed in a silver nitrate solution (AgNO). After Ag ions anchored in the COO groups are chemically reduced to produce AgNPs.

Mechanically improved polyvinyl alcohol-composite films using modified cellulose nanowhiskers as nano-reinforcement.

Cellulose nanowhiskers (CWs) extracted from cotton fibers were successfully modified with distinct anhydrides structures and used as additives in poly(vinyl alcohol) (PVA) nanocomposite films. The surface modification of CWs was performed with maleic, succinic, acetic or phthalic anhydride to compare the interaction and action the carboxylic groups into PVA films and how these groups influence in mechanical properties of the nanocomposites. CWs presented a high degree of crystallinity and good dispersion in water, with average length at the nanoscale.

The Inclusion of Chitosan in Poly-ε-caprolactone Nanoparticles: Impact on the Delivery System Characteristics and on the Adsorbed Ovalbumin Secondary Structure.

This report extensively explores the benefits of including chitosan into poly-ε-caprolactone (PCL) nanoparticles (NPs) to obtain an improved protein/antigen delivery system. Blend NPs (PCL/chitosan NPs) showed improved protein adsorption efficacy (84%) in low shear stress and aqueous environment, suggesting that a synergistic effect between PCL hydrophobic nature and the positive charges of chitosan present at the particle surface was responsible for protein interaction. Additionally, thermal analysis suggested the blend NPs were more stable than the isolated polymers and cytotoxicity assays in a primary cell culture revealed chitosan inclusion in PCL NPs reduced the toxicity of the delivery system.

Hybrid materials for bone tissue engineering from biomimetic growth of hydroxiapatite on cellulose nanowhiskers.

Cellulose nanowhiskers (CNWs) with different surface composition were used to generate the biomimetic growth hydroxyapatite (HAp). Hybrids materials primarily consist of CNWs with HAp content below 24%. CNWs were produced by different inorganic acid hydrolyses to generate cellulose particles with surface groups to induce HAp mineralization.

Covalently-layers of PVA and PAA and in situ formed Ag nanoparticles as versatile antimicrobial surfaces.

The in situ synthesis of silver nanoparticles (AgNPs) within covalently-modified poly(ethylene terephthalate) (PET) films possessing ultra-thin layer of poly(vinyl alcohol) (PVA) and poly(acrylic acid) (PAA) is successfully demonstrated. The resulting polymeric films are shown to exhibit antimicrobial activities toward Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria and fungus (Candida albicans). To make the films, first PET surfaces were subject to photo-oxidation and subsequent solid-state grafting to attach a PVA layer, followed by a PAA layer.

Controlling cell growth with tailorable 2D nanoholes arrays.

A facile and reproducible route that can lead to two-dimensional arrays of nanopores in thin polymer films is demonstrated. The formation of the pores in the polymer films involves breath figure phenomenon and occurs during the film deposition by spin coating. The formation of nanoporous thin films takes only few seconds, and the method does not require complex equipment or expensive chemicals.