Developing a drug delivery carrier from natural polysaccharide exudate gum by graft-copolymerization reaction using high energy radiations

Recent advances of Sterculia gums uses in drug delivery systems

Trees of the genus Sterculia produce polysaccharide-rich exudates, such as karaya gum (Sterculia urens), chicha gum (Sterculia striata), and Sterculia foetida gum. These anionic biomaterials are biodegradable, with high viscosity, low toxicity, and gelling properties in aqueous media. According to these properties, they show promising applications as a polymer matrix for use in drug delivery systems. For this application, both the chemically modified and the unmodified polysaccharide are used. This review focuses on analyzing the state of the art of recent studies on the use of Sterculia gums in a variety of pharmaceutical forms, such as tablets, hydrogels, micro/nanoparticles, and mucoadhesive films. Sterculia gums-based delivery systems have potential to be explored for new drug delivery systems.

Advances in Injectable and Self-healing Polysaccharide Hydrogel Based on the Schiff Base Reaction

Injectable hydrogel possesses great application potential in disease treatment and tissue engineering, but damage to gel often occurs due to the squeezing pressure from injection devices and the mechanical forces from limb movement, and leads to the rapid degradation of gel matrix and the leakage of the load material. The self-healing injectable hydrogels can overcome these drawbacks via automatically repairing gel structural defects and restoring gel function. The polysaccharide hydrogels constructed through the Schiff base reaction own advantages including simple fabrication, injectability, and self-healing under physiological conditions, and therefore have drawn extensive attention and investigation recently. In this short review, the preparation and self-healing properties of the polysaccharide hydrogels that is established on the Schiff base reaction are focused on and their biological applications in drug delivery and cell therapy are discussed.

Injectable thermosensitive hybrid hydrogel containing graphene oxide and chitosan as dental pulp stem cells scaffold for bone tissue engineering

Here, we fabricated thermosensitive injectable hydrogel containing poly (N-isopropylacrylamide) (PNIPAAm)-based copolymer/graphene oxide (GO) composite with different feed ratio to chitosan (CS) as a natural polymer through physical and chemical crosslinking for the proliferation and differentiation of the human dental pulp stem cells (hDPSCs) to the osteoblasts. The PNIPAAm copolymer/GO composite was synthesized by free-radical copolymerization of (N-isopropylacrylamide) (NIPAAm), itaconic acid (IA) and maleic anhydride-modified poly(ethylene glycol) (PEG) in the presence of GO and used for the preparation of the hydrogels. The formulated hydrogels were evaluated for the porous architecture, rheological behavior, compressive strength, swelling property, in vitro degradation, hemocompatibility, biocompatibility, and differentiation. The hydrogel could enhance the deposition of minerals and the activity of alkaline phosphatase (ALP), in large part attributable to the oxygen and amine-containing functional groups of GO and CS. The engineered hydrogel could also upregulate the expression of the Runt-related transcription factor 2 and osteocalcin in the hDPSCs cultivated in both the normal and osteogenic media. It seems to promote the absorption of osteogenic inducer too. Based on our findings, the engineered hydrogel demonstrated the osteogenic potential, upon which it is proposed as a constructing scaffold in bone tissue engineering for the transplantation of hDPSCs.

Synthesis and characteristics of a novel dust suppressant with good weatherability for controlling dust in open coal yards

This study aims to synthesize a dust suppressant for controlling coal dust pollution in open yards using natural polymers. Guided by graft copolymerization theory, potassium persulfate acts as an initiator to excite the free radicals of collagen and sodium alginate, allowing them to combine with acrylic acid and acrylamide to form a new polymer. The TG curve indicates that the thermal stability of the polymer is superior to that of the raw material. Scanning electron microscope (SEM) images show that the product can reduce the generation of dust by bonding the pulverized coal. With CCD method, when the monomer concentration increases in a certain range, the cohesive ability of the product to coal increases first and then decreases. Initiators and crosslinkers showed the same pattern. A series of performance experiments show that the product has a dust suppression rate of 98.7% at a wind speed of 14 m/s, and maintain one of 94.5% at a wind speed of 8 m/s after a rainstorm. In addition, there was no significant loss in dust suppression performance and compressive strength of the solidified layer after wind and rain. Sunlight, low temperature, and high temperature have little influence on the dust suppression effect of the product, which indicates that the product has better weather resistance and helps to suppress dust for a longer time in open air conditions.