•Polyvinyl alcohol/N–succinyl chitosan/lincomycin antibacterial hydrogels were prepared by the freezing/thrawing method.•The swelling behavior, mechanical strength, antibacterial activity and drug ...release were systematically investigated.•N–Succinyl chitosan enhanced the swelling capacity and mechanical strength.•The introducing of lincomycin improved the antibacterial activity with no cytotoxicity observed.
Hydrogels are three-dimensional polymeric networks capable of absorbing large amounts of water or biological fluids with the properties resembling natural living tissues. Herein, polyvinyl alcohol (PVA)/N–succinyl chitosan (NSCS)/lincomycin hydrogels for wound dressing were prepared by the freezing/thawing method, then characterized by FTIR, SEM, and TGA. The compression strength, swelling behavior, water retention capacity, antibacterial activity, drug release and cytotoxicity were systematically investigated. The results showed that the introduction of NSCS remarkably enhanced the swelling capacity, leading to the maximum swelling ratio of 19.68 g/g in deionized water. The optimal compression strength of 0.75 MPa was achieved with 30 % NSCS content.Additionally, the incorporation of lincomycin brought a remarkable antibacterial activity against both Escherichia coli and Staphylococcus aureus. Specifically, 77.71 % of Staphylococcus aureus was inhibited with 75 μg/mL lincomycin, while the MTT assay demonstrated the nontoxic nature of the composite hydrogels. In summary, this PVA/NSCS/lincomycin hydrogel showed promising potential for wound dressing.
The emergence of hydrogel ionotronics has significantly extended the applications of soft electronics by allowing intimate interfaces between electronic units and biological/engineered surfaces for ...better sensing and communication with surrounding stimuli. However, hydrogel ionotronic devices that combine high stretchability, self-healing, good water retention, and biocompatibility are still desired. Here, we report a biocompatible ionic hydrogel made of polyvinyl alcohol, silk fibroin, and borax. In this ionic hydrogel, polyvinyl alcohol and borax offer the high stretchability and conductivity, respectively, while silk fibroin improves the stability of the hydrogel and increases water uptake by the gels. The hydrogel features strain larger than 5000%, good water retention, self-healing, and tunable conductivity and adhesive capabilities. We also demonstrate the use of the hydrogel as a sensing platform to monitor human body motion for applications in health management, soft robotics, and human–machine interfaces.
Abstract Polyvinyl alcohol (PVA) cylindrical hydrogel with a stiffness gradient was prepared using a simple liquid nitrogen (LN2 )-contacting gradual freezing and thawing method in order to ...investigate the effects of substrate stiffness on stem cell differentiation into specific cell types. The prepared cylindrical PVA hydrogel showed a gradually increasing stiffness along the longitudinal direction from the top at approximately 1 kPa to the bottom (LN2 contacted side) at approximately 24 kPa. From the in vitro culture of bone marrow stem cells, it was observed that each soft (∼1 kPa) and stiff (∼24 kPa) hydrogel section promotes effective neurogenesis and osteogenesis of the cells, respectively, with the tendency to gradually decrease toward the opposing characteristic's side. The stiffness gradient cylindrical PVA hydrogel fabricated using this simple gradual freezing and thawing method can be a useful tool for basic studies, including the determination of optimum stiffness ranges for a variety of stem cell differentiations, as well as the investigation of cell migration in terms of substrate stiffness.
In the present study, a hybrid microsphere/hydrogel system, consisting of polyvinyl alcohol (PVA)/sodium alginate (SA) hydrogel incorporating PCL microspheres is introduced as a skin scaffold to ...accelerate wound healing. The hydrogel substrate was developed using the freeze-thawing method, and the proportion of the involved polymers in its structure was optimized based on the in-vitro assessments. The bFGF-encapsulated PCL microspheres were also fabricated utilizing the double-emulsion solvent evaporation technique. The achieved freeze-dried hybrid system was then characterized by in-vitro and in-vivo experiments. The results obtained from the optimization of the hydrogel showed that increasing the concentration of SA resulted in a more porous structure, and higher swelling ability, elasticity and degradation rate, but decreased the maximum strength and elongation at break. The embedding of PCL microspheres into the optimized hydrogel structure provided sustained and burst-free release kinetics of bFGF. Besides, the addition of drug-loaded microspheres led to no significant change in the degradation mechanism of the hydrogel substrate; however, it reduced its mechanical strength. Furthermore, the MTT assay represented no cytotoxic effect for the hybrid system. The in-vivo studies on a burn-wound rat model, including the evaluation of the wound closure mechanism, and histological analyses indicated that the fabricated scaffold efficiently contributed to promoting cell-induced tissue regeneration and burn-wound healing.
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•Components of PVA/OMP-RAs film are hydrogen bonded.•Mechanical and barrier properties are enhanced by the addition of OMP and RAs.•Distinguishable color changes occurring at pH ...2–12.•Effective monitoring the total volatile basic nitrogen below about 20 mg/100 g.
In this work, a colorimetric film was designed for shrimp freshness monitoring by incorporating rose anthocyanins (RAs) in polyvinyl alcohol/okra mucilage polysaccharide (PVA/OMP) composite film. The presence of OMP changed the film-forming solution from Newtonian to non-Newtonian fluid. The addition of OMP and RAs decreased the crystalline of PVA due to the hydrogen bonds among RAs, OMP and PVA. An appropriate content of RAs and OMP could improve the film mechanical and barrier properties. The colorimetric film showed distinguishable color changes at pH 2–12 and was high sensitive to volatile ammonia. The target film of PVA/OMP-RAs could effectively monitor shrimp freshness in real time and the color changes were easily distinguished by naked eye, suggesting its potential in intelligent packaging for freshness monitoring of aquatic products and meat foods.
Cryogels are support materials which are good at mimicking extracellular matrix due to their excellent hydrophilicity, biocompatibility, and macroporous structure, thus they are useful in ...facilitating cell activities during healing process. In this study, polyvinyl alcohol-gelatin (PVA-Gel) based cryogel membranes loaded with pterostilbene (trans-3,5-dimethoxy-4-hydroxystilbene; PTS) (PVA-Gel/PTS) was synthesized as wound dressing materials. PVA-Gel and PVA-Gel/PTS were synthesized with the polymerization yields of 96% ± 0.23% and 98% ± 0.18%, respectively, and characterized by swelling tests, Brunauer-Emmett-Teller (BET) and scanning electron microscopy (SEM) analysis. The swelling ratios were calculated as 98.6% ± 4.93% and 102% ± 5.1%, macroporosities were determined as 85% ± 2.13% and 88% ± 2.2%, for PVA-Gel and PVA-Gel/PTS, respectively. It was determined that PVA-Gel and PVA-Gel/PTS have 17 m
/g ± 0.76 m
/g and 20 m
/g ± 0.92 m
/g surface areas, respectively. SEM studies were demonstrated that they have ~100 μm pore sizes. According to 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), trypan blue exclusion and live-dead assay results, it was observed that cell proliferation, cell number and cell viability were higher in PVA-Gel/PTS cryogel at 24, 48, and 72 h compared to PVA-Gel. A strong and transparent fluorescent light intensity was observed indicating higher cell population in PVA-Gel/PTS in comparison with PVA-Gel, according to 4',6-diamidino-2-phenylindole (DAPI) staining. SEM, F-Actin, Giemsa staining and inverted-phase microscope image of fibroblasts in PVA-Gel/PTS cryogels revealed that dense fibroblast proliferation and spindle-shaped morphology of cells were preserved. Moreover, DNA agarose gel data demonstrated that PVA-Gel/PTS cryogels had no effect on DNA integrity. Consequently, produced PVA-Gel/PTS cryogel can be used as wound dressing material to promote wound therapies, inducing cell viability and proliferation.
The complex, gradient physiological structure of articular cartilage is a severe hindrance of its self‐repair, leaving the clinical treatment of cartilage defects a demanding issue to be addressed. ...Currently applied tissue engineering treatments and traditional non‐tissue engineering treatments have different limitations, for example, cell dedifferentiation, immune rejection, and prosthesis‐related complications. Thus, studies have been focusing on seeking promising candidates for novel cartilage repair methods. Polyvinyl alcohol (PVA) hydrogels with excellent biocompatibility and tunable material properties have become the alternatives. For pure PVA hydrogels, the mechanical strength and lubricity are not capable of replacing articular cartilage until proper modifications are done. This paper summarizes the research progress in PVA hydrogels, including the preparation, modification, and cartilage‐repair‐aimed biomimetic improvements. Design guidance of PVA hydrogels is put forward as assistance to functional hydrogel preparation. Finally, the prospects and main obstacles of PVA hydrogels are discussed.
In this paper, a comparison between traditional and hydrogel‐based cartilage repair technologies is done first, based on which the weakness of polyvinyl alcohol (PVA) hydrogel is brought up as well as corresponding strengthening mechanisms. Several cartilage‐repair‐aimed biomimetic improvements of PVA‐based hydrogels are also reviewed. Finally, design guidance of PVA‐based hydrogels is put forward together with main obstacles and prospects.
Non-healing wound is a serious complication of diabetes, associated with extremely slow wound closure, and a high rate of infection, resulting in amputation or losses of limbs, high health care cost ...and poor quality of patient's life. In the present study, we hypothesized that nanofiber mats composed of a combination of chitosan, polyvinyl alcohol (PVA) and Zinc oxide (ZnO) could be an effective option for faster healing of diabetic wounds due to the wound healing activities of chitosan-PVA nanofibers and antibacterial properties of ZnO. Nanofiber mats of chitosan, PVA and ZnO were synthesized using electrospinning technique. The developed nanofibrous mats were characterized by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), antibacterial and antioxidant assays as well as in vivo wound healing experiments in rabbits. The results revealed that chitosan/PVA/ZnO nanofibrous membranes possessed higher antibacterial potential against E. coli, P. aeruginosa, B. subtilis and S. aureus compared to chitosan/PVA nanofibrous membranes. Moreover, chitosan/PVA/ZnO nanofibrous membranes exhibited higher antioxidant potential compared to chitosan/PVA nanofibrous mats. The in vivo wound healing studies showed that chitosan/PVA/ZnO nanofibrous membranes resulted in accelerated wound healing as compared to chitosan/PVA nanofibers. The current study, thus, reveals that chitosan/PVA/ZnO electrospun scaffolds could be effectively helpful in dressings for diabetic wounds.
In this study, new synthesis strategies for poly (vinyl alcohol) (PVA) functionalized with azidation (Az) and alkynation (Alk) were carried out for surface functionality modification. These two ...functionalization routes utilize azide and alkyne groups, respectively, and offer simple way to enhance the PVA crosslinking capabilities toward producing new functional polymer-based materials. The Az functionalized PVA was prepared in two steps and denoted by PVA-Az, while Alk functionalized PVA was prepared in one step to produce PVA-Alk. Surfaces modification of PVA by using Az and Alk functional groups was confirmed by spectral analysis (Fourier transform infrared and sup.13C-NMR). Results showed that Alk prompted excellent chemical modifications on the surface of PVA while the thermal stability was enhanced by functionalizing the Az and Alk into PVA. Furthermore, X-ray photoelectron spectroscopy investigations showed a successful functionalization and new functional groups addition to PVA surface. Scanning electron microscope images were used to analyze the surface morphology of PVA by incorporating the Az and Alk groups, which indicated rougher surfaces compared to that of PVA backbone. In terms of efficiency and simplicity, the techniques used in this study appear to be entirely satisfactory.
Embedded extrusion printing provides a versatile platform for fabricating complex hydrogel‐based biological structures with living cells. However, the time‐consuming process and rigorous storage ...conditions of current support baths hinder their commercial application. This work reports a novel “out‐of‐the‐box” granular support bath based on chemically crosslinked cationic polyvinyl alcohol (PVA) microgels, which is ready to use by simply dispersing the lyophilized bath in water. Notably, with ionic modification, PVA microgels yield reduced particle size, uniform distribution, and appropriate rheological properties, contributing to high‐resolution printing. Following by the lyophilization and re‐dispersion process, ion‐modified PVA baths recover to its original state, with unchanged particle size, rheological properties, and printing resolution, demonstrating its stability and recoverability. Lyophilization facilitates the long‐term storage and delivery of granular gel baths, and enables the application of “out‐of‐the‐box” support materials, which will greatly simplify experimental procedures, avoid labor‐intensive and time‐consuming operations, thus accelerating the broad commercial development of embedded bioprinting.
This study develops an “out‐of‐the‐box” granular support bath that is ready to use by simply dispersing the lyophilized bath in a solvent. Re‐dispersed bath displays same physicochemical property, shear‐thinning and self‐healing properties, and printing resolution with the fresh one. The lyophilized bath facilitates long‐term storage and delivery, thereby simplifying experimental procedures, saving time and money, and enabling the construction of scale‐up tissue‐like structures.
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