Metal/metal oxide-carbohydrate polymers framework for industrial and biological applications: Current advancements and future directions

Recently, the development and consumption of metal/metal oxide carbohydrate polymer nanocomposites (M/MOCPNs) are withdrawing significant attention because of their numerous salient features. Metal/metal oxide carbohydrate polymer nanocomposites are being used as environmentally friendly alternatives for traditional metal/metal oxide carbohydrate polymer nanocomposites exhibit variable properties that make them excellent prospects for a variety of biological and industrial uses. In metal/metal oxide carbohydrate polymer nanocomposites, carbohydrate polymers bind with metallic atoms and ions using coordination bonding in which heteroatoms of polar functional groups behave as adsorption centers. Metal/metal oxide carbohydrate polymer nanocomposites are widely used in woundhealing, additional biological uses and drug delivery, heavy ions removal or metal decontamination, and dye removal. The present review article features the collection of some major biological and industrial applications of metal/metal oxide carbohydrate polymer nanocomposites. The binding affinity of carbohydrate polymers with metal atoms and ions in metal/metal oxide carbohydrate polymer nanocomposites has also been described.

Amorphous cobalt oxide decorated halloysite nanotubes for efficient sulfamethoxazole degradation activated by peroxymonosulfate

In this study, a new hollow nanotube material, 30% Co-CHNTs was prepared by the impregnation-chemical reduction-calcination method. This material can be used as a peroxymonosulfate (PMS) activator to catalyse the degradation of sulfamethoxazole (SMX). The best reaction conditions that correspond to the degradation rate of SMX, up to 97.5%, are as follows: the concentration of SMX is 10 mg L^-1, the amount of catalyst is 0.20 g L^-1, the dosage is 1.625 mM, and the solution pH is 6.00. X-ray photoelectron spectroscopy (XPS) and inductively coupled plasma optical emission spectrometry (ICP-OES) show that the calcined composites mainly stimulate an increase in the content of bivalent cobalt in PMS and reduce the leaching of cobalt ions after the reaction. Additionally, the 30% Co-CHNTs + PMS reaction system exhibits a reasonable SMX degradation rate in a natural organic matter solution and excellent stability after three repeated experiments. Furthermore, the possible degradation mechanism in the 30% Co-CHNTs + PMS reaction system was analysed through electron paramagnetic resonance (EPR) and free-radical capture experiments, and it was observed that the non-radical degradation of ¹O₂ plays a leading role in SMX degradation. Finally, according to the nine degradation intermediates detected by liquid chromatography-mass spectrometry (LC-MS), four possible SMX degradation routes were proposed. This study proved that a 30% Co-CHNTs heterogeneous catalyst is easily prepared, inexpensive, and environmentally friendly and has potential application in antibiotic wastewater treatment.

Lotus leaf-inspired design of calcium alginate particles with superhigh drug encapsulation efficiency and pH responsive release

Drug delivery systems with high drug encapsulation efficiency and controlled release are of great importance in biomedical fields. Herein, we report an ingenious approach inspired from the lotus leaf possessing the ability of strong repellency to water, which enables the rapid fabrication of drug-loaded calcium alginate (Ca-Alg) particles with high drug encapsulation efficiency and controlled drug delivery. The design is achieved by introducing aqueous droplets containing the mixture of dilute sodium alginate solution, dilute calcium chloride solution, and drug onto the superhydrophobic substrate. Due to water evaporation both the concentration of sodium alginate and calcium chloride within the droplets will gradually increase, and the ionic crosslinking reaction of sodium alginate with Ca²⁺ is further occurred to form the drug-embedded Ca-Alg hydrogel particles. The results indicate that the controllable fabrication of Ca-Alg particles can be easily achieved on the superhydrophobic surface, and the swelling behavior can be tuned by the pH of the buffer solution. Importantly, the drug encapsulation efficiencies are measured to be over 88% and the drug exhibits obvious pH responsive release. Findings from this study are expected to contribute to the rational design of drug delivery systems with high drug encapsulation efficiency and controlled release for pharmaceutic science and tissue engineering.

Smart H2O2-Responsive Drug Delivery System Made by Halloysite Nanotubes and Carbohydrate Polymers

A novel chemical hydrogel was facilely achieved by coupling 1,4-phenylenebisdiboronic acid modified halloysite nanotubes (HNTs-BO) with compressible starch. The modified halloysite nanotubes (HNTs) and prepared hydrogel were characterized by solid-state nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and transmission electron microscope (TEM). The linkage of B-C in the hydrogel can be degraded into B-OH and C-OH units in the presence of H₂O₂ and result in the degradation of the chemical hydrogel. Pentoxifylline was loaded into the lumen of the HNTs-BO, and then gave the pentoxifylline-loaded hydrogel. The drug release profile shows that it was no more than 7% dissolved when using phosphate buffer solution (PBS) as the release medium. Notably, a complete release (near 90%) can be achieved with the addition of H₂O₂ ([H₂O₂] = 1 × 10^-4 M), suggesting a high H₂O₂ responsiveness of the as-formed hydrogel. The drug release results also show that the "initial burst release" can be effectively suppressed by loading pentoxifylline inside the lumen of the HNTs rather than embedding the drug in the hydrogel network. The drug-loaded hydrogel with H₂O₂-responsive release behavior may open up a broader application in the field of biomedicine.