Smart superabsorbent UV resistant etherified PVA gel: Synthesis and characterization

Initiator-Free Photocuring 3D-Printable PVA-Based Hydrogel with Tunable Mechanical Properties and Cell Compatibility

Poly(vinyl alcohol) (PVA)-based hydrogels have attracted great attention and been widely used in biological tissue engineering. With the development of modern medicine, precision medicine requires the customization of medical materials. However, lacking of photocurable functional groups or the performance of rapid phase transition makes PVA-based hydrogels difficult to be customizable molded through photocuring 3D printing technique. In this research, customizable PVA-based hydrogels with high performance through 3D photocurable printing and freezing-thawing (F-T) process are obtained. The ability of 3D-printable is endowed by the introduction of polyvinyl alcohol-styrylpyridine (PVA-SBQ), which can be photo-crosslinked quickly without photoinitiator. Meanwhile, the tunable mechanical properties are achieved by adjusting the mass ratio of PVA-SBQ to PVA, and PVA can offer the physical crosslinking points through freezing-thawing (F-T) process. The hydrogels with high resolution are prepared by digital light procession 3D printing with the mass ratio 1:1 of PVA-SBQ to PVA solution. Attributed to the absence of initiator, and no small molecule residues inside the hydrogels, the hydrogels have good biocompatibility and have the potential to be applicated in the field of biological tissue engineering.

Mussel-inspired biocompatible polydopamine/carboxymethyl cellulose/polyacrylic acid adhesive hydrogels with UV-shielding capacity

Hydrogels are attractive due to their various applications in the fields of biomedical materials, cosmetics, and biosensors. To enhance UV protection and prevent skin penetration behaviors, inspired by the mussel adhesive proteins, the functional polydopamine (PDA) is employed herein to fabricate polydopamine/carboxymethyl cellulose/polyacrylic acid (PDA/CMC/PAA) adhesive hydrogels. To disperse PDA nanoparticles well in the PAA matrix, dopamine was self-polymerized in CMC solution to form PDA/CMC complex. Acrylic acid was polymerized in PDA/CMC complex solution and cross-linked to construct UV-resistant PDA/CMC/PAA hydrogel. The morphology, rheological behavior, mechanical properties and adhesion strength of PDA/CMC/PAA hydrogels were studied by scanning electron microscopy, rotational rheometer, universal test machine. Owing to the hydrogen bonding interaction between the PDA/CMC complex and PAA, the PDA/CMC/PAA hydrogels showed high resilience and compressive strength to withstand large deformation. The hydrogels exhibited strong adhesion to various substrate surfaces, such as stainless steel, aluminum, glass and porcine skin. The biocompatibility and UV-shielding properties were investigated through culture of cells and UV irradiation test. The adhesiveness of PDA promoted cell adhesion and provided the PDA/CMC/PAA hydrogels good biocompatibility with 96% of relative cell viability. The hydrogels possessed excellent UV-shielding ability to prevent collagen fibers from being destroyed during UV irradiation, which has promising potential in the practical applications for UV filtration membrane and skin care products.

Fabrication of polyvinyl alcohol hydrogels with excellent shape memory and ultraviolet-shielding behavior via the introduction of tea polyphenols

Shape-memory hydrogels are expected to be used not only in an ordinary environment, but also in some special environments, such as under ultraviolet (UV) irradiation. Developing novel shape-memory polyvinyl alcohol (PVA)/tea polyphenol (TP) hydrogels with UV shielding performance is realistically important in application fields. Herein, we designed functional PVA/TP hydrogels with excellent UV-shielding ability and improved the shape memory on hot water stimuli. This study shows that the abundant hydrogen bonds between PVA and TP are the source of shape memory. The PVA hydrogels with 8 wt% TP loading could approximately recover their original shape after deformation when immersed in water at 50 °C for 30 s. Meanwhile, the hydrogels also had excellent UV shielding capacity. After ageing under UV for 16 days, the observed shape of the hydrogel with 8 wt% TP loading retained 74.7% of the original, and the hydrogel could effectively protect the skin of mice from damage under 10 mW cm-2 UV irradiation. With the understanding of the UV-shielding behavior of hydrogels, this study has been able to generate biomedical materials for human skin protection, specifically skin covering the joint areas, where shape memory of the applied materials is essential.

Aquasorbent guargum grafted hyperbranched poly (acrylic acid): A potential culture medium for microbes and plant tissues

This study reports the synthesis of an unprecedented bio-based aquasorbent guargum-g-hyperbranched poly (acrylic acid); bGG-g-HBPAA by employing graft-copolymerization and "Strathclyde methodology" simultaneously in emulsion and its possible use as a sustainable nutrient bed for the effective growth of Anabaena cylindrica and Vigna radiata seedlings. The formation of bGG-g-HBPAA and the presence of hyperbranched architectures was confirmed from XRD, FTIR, ¹³C NMR, solubility, intrinsic viscosity, BET surface area/ pore size, SEM and rheology analyses. The synthesized grade with a branching percent of 65.4% and a swelling percentage of 13,300% facilitated maximum growth of the cultured species as compared to guargum and its linear graft. Semi synthetic bGG-g-HBPAA culture medium was optically transparent, dried at a controlled rate, held a huge amount of water for growth, provided sufficient space for unhindered growth and featured dimensional stability.