Synergistic effect and molecular mechanism of PVA and UM171 in ex vivo expansion of primitive hematopoietic stem cells.

Umbilical cord blood (UCB) is a valuable source of hematopoietic stem cells (HSCs) used for transplantation; the number of cells in a single UCB is too small to quickly establish bone marrow (BM) implantation, and ex vivo expansion of HSCs has the potential to overcome this limitation. The purpose of this study is to explore the culture conditions conducive to the maintenance and expansion of hematopoietic stem and progenitor cells (HSPCs) and long-term hematopoietic stem cells (LT-HSCs) derived from human umbilical cord blood, compare the different effects of albumin (HSA) and polyvinyl alcohol (PVA), optimize the culture system using UM171 and investigate the molecular mechanism of PVA and UM171 promoting the expansion of primitive hematopoietic stem cells. CD34+ cells were purified from UCB using MacsCD34 beads, and then cultured in serum-free medium supplemented with cytokines for 12 days, with PVA or UM171 added according to experimental requirements; the relative percentage of different HSCs subsets after culture were detected by flow cytometry; CFU Assay Setup for detecting the multilineage differentiation potential of HSCs; RT-PCR detection of gene expression levels; reactive oxygen detection assessment of intracellular ROS levels. (1) The conditions of 20 ng/mlSCF, 100 ng/mlTPO, and 5% oxygen concentration are conducive to the maintenance of LT-HSCs. (2) Compared with HSA, PVA significantly increased the proportion of HSPCs and LT-HSCs, as well as dramatically promoted the expression of antioxidant enzymes and reduced the production of reactive oxygen species (ROS). (3) After adding UM171 to PVA-based medium, the proportion of HSPCs and LT-HSCs further increased, and downstream genes of Notch and Wnt pathways were selectively activated. (1) PVA may inhibit ROS production by upregulating the expression of antioxidant enzymes, which is beneficial for maintaining stemness and inhibiting differentiation of HSCs. (2) The antioxidant properties of PVA can delay differentiation, while UM171 can promote self-renewal by regulating the stem cell pathway, and the combination of them is beneficial for the maintenance and expansion of HSCs in vitro.

Highly Biocompatible Antibacterial Hydrogel for Wearable Sensing of Macro and Microscale Human Body Motions.

Flexible electronics, like electronic skin (e-skin), rely on stretchable conductive materials that integrate diverse components to enhance mechanical, electrical, and interfacial properties. However, poor biocompatibility, bacterial infections, and limited compatibility of functional additives within polymer matrices hinder healthcare sensors' performance. This study addresses these challenges by developing an antibacterial hydrogel using polyvinyl alcohol (PVA), konjac glucomannan (KGM), borax (B), and flower-shaped silver nanoparticles (F-AgNPs), referred as PKB/F-AgNPs hydrogel. The developed hydrogel forms a hierarchical network structure, with a tensile strength of 96 kPa, 83% self-healing efficiency within 60 minutes, and 128% cell viability in Cell Counting Kit-8 (CCK-8) assays, indicating excellent biocompatibility. It also shows strong antibacterial efficacy against Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus). Blue light irradiation enhances its antibacterial activity by 1.3-fold for E. coli and 2.2-fold for S. aureus. The hydrogel's antibacterial effectiveness is assessed by monitoring changes in electrical conductivity, providing a cost-effective alternative to traditional microbial culture assays. The PKB/F-AgNPs hydrogel's flexibility and electrical conductivity enable it to function as strain sensors for detecting body movements and facial expressions. This antibacterial hydrogel underscores its potential for future human-machine interfaces and wearable electronics.

Biomimetic Multiscale Oriented PVA/NRL Hydrogel Enabled Multistimulus Responsive and Smart Shape Memory Actuator.

Shape memory hydrogels provide a worldwide scope for functional soft materials. However, most shape memory hydrogels exhibit poor mechanical properties, leading to low actuation strength, which severely limits their applications in smart biomimetic devices. Herein, a strategy for muscle-inspired shape memory-oriented polyvinyl alcohol (PVA)-natural rubber latex (NRL) hydrogel (OPNH) with multiscale oriented structure is demonstrated. The shape memory function comes from the stretch-induced crystallization of natural rubber (NR), while PVA forms strong hydrogen bonding interactions with proteins and phospholipids on the surface of NRL particles. Meanwhile, the reconfigurable interactions of PVA and NR produce a multiscale-oriented structure during stretch-drying, improving the mechanical and shape memory properties. The resultant OPNH shows excellent interfacial compatibility, exhibiting outstanding mechanical performance (3.2 MPa), high shape fixity (≈80%) and shape recovery ratio (≈92%), high actuation strength (206 kPa), working capacity (105 kJ m- 3), extremely short response time (≈2 s), low response temperature (28 °C) and smart thermal responsiveness. It can even maintain muscle-like working capacity when lifting a load equivalent to 372 times its weight, providing a new class shape memory material for the application in smart biomimetic muscles and multistimulus responsive devices.

Stable Zinc Anode Facilitated by Regenerated Silk Fibroin-modified Hydrogel Protective Layer.

Inherent dendrite growth and side reactions of zinc anode caused by its unstable interface in aqueous electrolytes severely limit the practical applications of zinc-ion batteries (ZIBs). To overcome these challenges, a protective layer for Zn anode inspired by cytomembrane structure is developed with PVA as framework and silk fibroin gel suspension (SFs) as modifier. This PVA/SFs gel-like layer exerts similar to the solid electrolyte interphase, optimizing the anode-electrolyte interface and Zn2+ solvation structure. Through interface improvement, controlled Zn2+ migration/diffusion, and desolvation, this buffer layer effectively inhibits dendrite growth and side reactions. The additional SFs provide functional improvement and better interaction with PVA by abundant functional groups, achieving a robust and durable Zn anode with high reversibility. Thus, the PVA/SFs@Zn symmetric cell exhibits an ultra-long lifespan of 3150 h compared to bare Zn (182 h) at 1.0 mAh cm-2-1.0 mAh cm-2, and excellent reversibility with an average Coulombic efficiency of 99.04% under a large plating capacity for 800 cycles. Moreover, the PVA/SFs@Zn||PANI/CC full cells maintain over 20 000 cycles with over 80% capacity retention under harsh conditions at 5 and 10 A g-1. This SF-modified protective layer for Zn anode suggests a promising strategy for reliable and high-performance ZIBs.

Photoinduced On and Off Polymeric Room Temperature Phosphorescence Based On Polycyclic Aromatic Hydrocarbon Isomers.

As family members of polycyclic aromatic hydrocarbons, compound anthracene (Ant) and phenanthrene (Phe) as isomers are widely used in organic optical materials and electronic materials. But their photochemical and physical properties are very different. In this work, the room temperature phosphorescence (RTP) properties of PVA-B-Ant and PVA-B-Phe are discussed carefully which are prepared by B-O click reaction through polyvinyl alcohol (PVA) with 9-anthraceneboronic acid (B-Ant) and 9-phenanthrenylboronic acid (B-Phe), respectively. PVA-B-Phe 1% film exhibits excellent fluorescence (FL) emission at 374 nm and RTP emission at 523 nm with green afterglow and around 1.9 s phosphorescence lifetime. However, PVA-B-Ant 1% film only shows strong blue FL emission at 414 nm, and the emission intensity decreases seriously with the extension of irradiation time. Experimental and theoretical calculations results suggest that the photodimer of Ant which is formed in PVA matrix under the UV light irradiation would be competitive with the process of RTP emission. This work demonstrates that the RTP properties of organic molecules might be probably affected by the photostability of the organic phosphor under UV irradiation.

Extraction of cellulose from halophytic plants for the synthesis of a novel biocomposite.

Cellulose nanofibers, a sustainable and promising material with widespread applications, exhibit appreciable strength and excellent mechanical and physicochemical properties. The preparation of cellulosic nanofibers from food or agricultural residue is not sustainable. Therefore, this study was designed to use three halophytic plants (Cressa cretica, Phragmites karka, and Suaeda fruticosa) to extract cellulose for the subsequent conversion to cellulosic nanofibers composites. The other extracted biomass components including lignin, hemicellulose, and pectin were also utilized to obtain industrially valuable enzymes. The maximum pectinase (31.56 IU mL-1), xylanase (35.21 IU mL-1), and laccase (15.89 IU mL-1) were produced after the fermentation of extracted pectin, hemicellulose, and lignin from S. fruticosa, P. karka, and C. cretica, respectively. Cellulose was methylated (with a degree of substitution of 2.4) and subsequently converted into a composite using polyvinyl alcohol. Scanning electron microscopy and Fourier-transform infrared spectroscopy confirmed the successful synthesis of the composites. The composites made up of cellulose from C. cretica and S. fruticosa had a high tensile strength (21.5 and 15.2 MPa) and low biodegradability (47.58% and 44.56%, respectively) after dumping for 3 months in soil, as compared with the composite from P. karka (98.79% biodegradability and 4.9 MPa tensile strength). Moreover, all the composites exhibited antibacterial activity against gram-negative bacteria (Escherichia coli and Klebsiella pneumoniae) and gram-positive bacteria (Staphylococcus aureus). Hence, this study emphasizes the possibility for various industrial applications of biomass from halophytic plants.

Effect of Different Ratios of Polyvinyl Alcohol-Gum Odina for the Preparation and Characterization of Biodegradable Composite Films.

This research investigates the production of biodegradable films using a combination of gum odina (GO) and polyvinyl alcohol (PVA) with varied ratio. The study focuses on the chemical, physical, and mechanical properties of PVA-GO composite films, emphasizing how versatile and biodegradable they may be for a range of packaging applications. Solvent-cast PVA-GO films with different ratios are subjected to a methodical analytical process to determine several parameters like mechanical qualities, thermal stability, biodegradability in soil, contact angle, transparency, water vapor permeability, moisture content, thickness, density, water solubility, microstructure, and FTIR analysis. The outcomes demonstrate that GO improves UV barrier qualities and water vapor permeability. Additionally, the films showed notable biodegradability, acceptable thermal stability, and mechanical qualities. In short, PVA-GO films can provide an eco-friendly packing substitute with adaptable qualities fit for a range of uses. Therefore, this research may further contribute promising information in the field of biodegradable packaging materials in the future.

Bronchial artery embolization using small particles is safe and effective: a single center 12-year experience.

BACKGROUND: Bronchial artery embolization (BAE) using particles is an established treatment for hemoptysis. The use of polyvinyl alcohol (PVA) with a particle size of 300 µm or larger is thought to reduce the risk of non-target embolization but may result in more proximal vessel occlusion than is ideal, resulting in a high rate of early recurrent hemorrhage. OBJECTIVE: This study evaluates the safety and efficacy of BAE using PVA particles with a size of less than 300 µm. METHODS: All patients who underwent BAE between 2010 and 2022 at a tertiary center were included. Demographic data, etiology and volume of hemoptysis, technical and clinical success, procedure-related complications, and follow-up information were collected from patients' electronic records. 150-250 µm PVA particles were used to commence embolization in all patients with the subsequent use of larger-sized particles in some individuals. The Kaplan-Meier method was used to estimate recurrence and survival rates. RESULTS: One hundred forty-four patients underwent 189 embolization procedures between 2010 and 2022 and were followed up for a median of 35 months [IQR 19-89]. 150 µm to 250 µm PVA particles were used as the sole embolic agent in 137 cases. Hemoptysis recurred within 30 days in 7%. The median time to repeat intervention was 144 days [IQR 42-441]. Seventeen out of 144 patients had a pulmonary artery branch pseudoaneurysm. The rate of major complications was 1% with no instances of stroke or spinal artery ischemia. Thirty-day mortality was 2% (4/189). CONCLUSION: BAE using 150-250 µm PVA particles is safe and effective with few complications and low rates of early hemoptysis recurrence. CLINICAL RELEVANCE STATEMENT: BAE using small particles is likely to improve outcomes, particularly the rate of early recurrence, in patients with hemoptysis, without an increase in procedural complications. KEY POINTS: BAE is a safe and effective treatment for patients with hemoptysis. Using small PVA particles in BAE has few complications and low rates of early recurrence. Pulmonary artery pseudoaneurysms should be actively sought in those with hemoptysis undergoing BAE.

Comparing embolic particles for prostatic artery embolization to treat lower urinary tract symptoms in patients with benign prostatic hyperplasia.

PURPOSE: Compare the safety and efficacy of polyvinyl alcohol particles (PVA) versus trisacryl gelatin microspheres (Embospheres) versus hydrogel microspheres coated with polyzene-F (Embozenes) for prostatic artery embolization (PAE) to treat patients with benign prostatic hyperplasia (BPH). MATERIALS AND METHODS: A single-center prospective cohort study from 2019 to 2023, including patients with international prostate symptom score (IPSS) ≥ 15 and/or quality of life score (QoL) ≥ 4. Allocation to embolic agents was performed chronologically: 100-300 µm PVA (n = 53), followed by 300-500 µm Embospheres (n = 50), and finally, 400 µm Embozenes (n = 50). All patients were evaluated at baseline and at 1 and 6 months after PAE with IPSS/QoL; peak urinary flow rate, post-void residual volume, and prostate volume with ultrasound and prostate-specific antigen. Adverse events and the need for prostatic re-interventions were assessed. RESULTS: There were no significant baseline differences between the three groups except for patient age (62.5 years PVA; 66.1 years Embospheres and 66.6 years Embozenes; p = 0.019). There were no major adverse events and no differences between groups regarding minor adverse events. All outcome measures improved significantly from baseline, with no significant differences between groups. Mean ± standard deviation IPSS/QoL improvement at 6 months: -10.7 ± 7.9/-2.2 ± 1.7 PVA; -10.4 ± 7.3/-2.0 ± 1.5 Embospheres; -10.4 ± 7.0/-2.2 ± 1.6 Embozenes (p = 0.987). Re-intervention rates after 6 months: 9% (n = 5/53) PVA; 14% (n = 7/50) Embospheres; 8% (n = 4/50) Embozenes (p = 0.591). CONCLUSIONS: PAE with PVA particles, Embospheres, and Embozenes is equally safe and effective in treating BPH-related lower urinary tract symptoms. CLINICAL RELEVANCE STATEMENT: This is the first prospective study showing equivalence between the most frequently used embolic agents for prostatic artery embolization. KEY POINTS: Different particles can be used interchangeably for prostatic artery embolization. The improvements in measured metrics were the same between groups, with no differences in adverse events. The need for prostatic medication and re-intervention rates were the same at 1 and 6 months after embolization.

Fabrication and Characterization of Dissolving Microneedles for Transdermal Drug Delivery of Apomorphine Hydrochloride in Parkinson's Disease.

PURPOSE: We fabricated and characterized polyvinyl alcohol (PVA)-based dissolving microneedles (MNs) for transdermal drug delivery of apomorphine hydrochloride (APO), which is used in treating the wearing-off phenomenon observed in Parkinson's disease. METHODS: We fabricated MN arrays with 11 × 11 needles of four different lengths (300, 600, 900, and 1200 µm) by micromolding. The APO-loaded dissolving MNs were characterized in terms of their physicochemical and functional properties. We also compared the pharmacokinetic parameters after drug administration using MNs with those after subcutaneous injection by analyzing the blood concentration of APO in rats. RESULTS: PVA-based dissolving MNs longer than 600 µm could effectively puncture the stratum corneum of the rat skin with penetrability of approximately one-third of the needle length. Although APO is known to have chemical stability issues in aqueous solutions, the drug content in APO-loaded MNs was retained at 25°C for 12 weeks. The concentration of APO after the administration of APO-loaded 600-µm MNs that dissolved completely in skin within 60 min was 81%. The absorption of 200-µg APO delivered by MNs showed a Tmax of 20 min, Cmax of 76 ng/mL, and AUC0-120 min of 2,829 ng・min/mL, compared with a Tmax of 5 min, Cmax of 126 ng/mL, and AUC0-120 min of 3,224 ng・min/mL for subcutaneous injection. The bioavailability in terms of AUC0-120 min of APO delivered by MNs was 88%. CONCLUSION: APO-loaded dissolving MNs can deliver APO via skin into the systemic circulation with rapid absorption and high bioavailability.

Transcutaneous Delivery of Dexamethasone Sodium Phosphate Via Microneedle-Assisted Iontophoretic Enhancement - A Potential Therapeutic Option for Inflammatory Disorders.

AIM: This study aimed to fabricate dexamethasone sodium phosphate loaded microneedle arrays (MNA) and investigate their efficiency in combination with iontophoresis for the treatment of hind paw oedema in rats. METHODS: Drug loaded polyvinyl alcohol, polyvinyl pyrrolidone and D-sorbitol-based MNA11 were fabricated by vacuum micromolding. Physicochemical, morphological, thermal, in-silico, in-vitro insertion ability (on parafilm) and drug release studies were performed. Ex-vivo permeation, in-vivo insertion and anti-inflammatory studies were performed in combination with iontophoresis. RESULTS: MNA11 displayed sharp-tipped projections and acceptable physicochemical features. Differential scanning calorimetry results indicated that drug loaded MNA11 were amorphous solids. Drug interacted with PVP and PVA predominately via hydrogen bonding. Parafilm displayed conspicuously engraved complementary structure of MNA11. Within 60 min, 91.50 ± 3.1% drug released from MNA11. A significantly higher i.e., 95.06 ± 2.5% permeation of drug was observed rapidly (within 60 min) from MNA11-iontophoresis combination than MNA11 i.e., 84.07 ± 3.5% within 240 min. Rat skin treated using MNA11 and MNA11-iontophoresis showed disruptions / microchannels in the epidermis without any damage to underlying anatomical structures. MNA11-iontophoresis combination led to significant reduction (83.02 ± 3.9%) in paw oedema as compared to MNA11 alone (72.55 ± 4.1%). CONCLUSION: MNA11-iontophoresis combination can act as a promising candidate to deliver drugs transcutaneously for treating inflammatory diseases.

High Strength UV-Resistant Composite Film of Fe3+-Coordination Lignin/PVA.

The literature on polyvinyl alcohol (PVA) films is extensive, however, these methods often necessitate intricate synthesis processes or the addition of plasticizers to modify the strength and water solubility of the PVA material. A high-strength UV radiation-resistant composite film by chelating Fe3+ with lignin and PVA, which exhibits excellent hydrolysis resistance is developed. This composite film is prepared simply by incorporating a small amount of dealkalized lignin (APPL) and ferric chloride (FeCl3) into PVA through a straightforward composite process. During the scanning test, it is noted that the film exhibits a high density of uniformly dispersed particles, endowing it with efficient ultraviolet absorption capabilities. The infrared and anti-dissolution tests reveal that the coordination of Fe3+ with lignin imparts an outstanding hydrolysis resistance to the film, obviating the need for any extender, curing agent, acid or base. The tensile fracture strength reaches an impressive 187.81Mpa in the tensile test. UV and indicator card tests unequivocally demonstrate that the film achieves a remarkable 100% anti-UV efficiency. This Fe3+ chelated lignin/PVA composite film, with its facile preparation, environmental sustainability, high strength, and outstanding anti-ultraviolet efficiency, can be deployed across diverse applications requiring robust protection against ultraviolet radiation.

Scalable Fabrication of Structurally Stable Polymer Film with Excellent UV-Shielding, Fluorescent, and Antibacterial Capabilities.

This research presents a new approach to facilely fabricating a multifunctional film using polyvinyl alcohol (PVA) as the base material. The film is modified chemically to incorporate various desirable properties such as high transparency, UV-shielding, antibacterial activity, and fluorescence. The fabrication process of this film is straightforward and efficient. The modified film showed exceptional UV-blocking capability, effectively blocking 100% of UV radiation. It also exhibits strong antibacterial properties. Additionally, the film emitted bright blue fluorescence, which can be useful in various optical and sensing applications. Despite the chemical modification, the film retained the excellent properties of PVA, including high transparency (90%) at 550 nm and good mechanical strength. Furthermore, it demonstrated remarkable stability even under harsh conditions such as exposure to long-term UV radiation, extreme temperatures (-40 or 120 °C), or immersion in different solvents. Overall, this work showcases a promising strategy to develop versatile, structurally stable, transparent, and flexible polymer films with multiple functionalities. These films have potential applications in various fields that require protection, such as packaging materials, biomedical devices, and optical components.

Cannabidiol-loaded microparticles embedded in a porous hydrogel matrix for biomedical applications.

In this study, poly (lactic-co-glycolic acid) (PLGA) microparticles loaded with cannabidiol (CBD) were synthesized (PLGA@CBD microparticles) and embedded up to 10 wt% in a chondroitin sulfate/polyvinyl alcohol hydrogel matrix. In vitro chemical, physical, and biological assays were carried out to validate the potential use of the modified hydrogels as biomaterials. The microparticles had spherical morphology and a narrow range of size distribution. CBD encapsulation efficiency was around 52%, loading was approximately 50%. Microparticle addition to the hydrogels caused minor changes in their morphology, FTIR and thermal analyses confirmed these changes. Swelling degree and total porosity were reduced in the presence of microparticles, but similar hydrophilic and degradation in phosphate buffer solution behaviors were observed by all hydrogels. Rupture force and maximum strain at rupture were higher in the modified hydrogels, whereas modulus of elasticity was similar across all materials. Viability of primary human dental pulp cells up to 21 days was generally not influenced by the addition of PLGA@CBD microparticles. The control hydrogel showed no antimicrobial activity against Staphylococcus aureus, whereas hydrogels with 5% and 10% PLGA@CBD microparticles showed inhibition zones. In conclusion, the PLGA@CBD microparticles were fabricated and successfully embedded in a hydrogel matrix. Despite the hydrophobic nature of CBD, the physicochemical and morphological properties were generally similar for the hydrogels with and without the CBD-loaded microparticles. The data reported in this study suggested that this original biomaterial loaded with CBD oil has characteristics that could enable it to be used as a scaffold for tissue/cellular regeneration.

Bone formation by Irisin-Poly vinyl alchol modified bioglass ceramic beads in the rabbit model.

In the aging society, slow bone regeneration poses a serious hindrance to the quality of life. To deal with this problem, in this study, we have combined irisin with the bioglass regular beads to enhance the bone regeneration process. For this purpose, highly porous bioglass was obtained as spherical beads by using sodium alginate. The bioglass was evaluated by various analytical techniques such as SEM, EDS, XRD, and pore size distribution. The results depicted that porous bioglass was prepared correctly and SEM analysis showed a highly porous bioglass was formulated. On this bioglass, irisin was loaded with the assistance of polyvinyl alcohol (PVA) in three concentrations (50 ng/ml, 100 ng/ml, and 150 ng/ml per 1 g of bioglass). SEM analysis showed that pores are covered with PVA. The irisin release profile showed a sustained release over the time period of 7 days. In vitro, biocompatibility evaluation by the MC3T3E1 cells showed that prepared bioglass and irisin loaded bioglass (BGI50, BGI100, and BG150) are highly biocompatible. Alizarin Red staining analysis showed that after 2 weeks BGI50 samples showed highest calcium nodule formation. In vivo in the rabbit femur model was conducted for 1 and 2 months. BGI150 samples showed highest BV/TV ratio of 37.1 after 2 months. The histological data showed new bone formation surrounding the beads and with beads loaded with irisin. Immunohistochemistry using markers OPN, RUNX, COL, and ALP supported the osteogenic properties of the irisin-loaded bioglass beads. The results indicated that irisin-loaded bioglass displayed remarkable bone regeneration.

Controlled Release of Lysozyme Using Polyvinyl Alcohol-Based Polymeric Nanofibers Generated by Electrospinning.

Polymeric nanofibers generated via electrospinning offer a promising platform for drug delivery systems. This study examines the application of electrospun polyvinyl alcohol (PVA) nanofibers for controlled lysozyme (LZM) delivery. By using various PVA grades, such as the degree of polymerization/hydrolysis, this study investigates their influence on nanofiber morphology and drug-release characteristics. LZM-loaded PVA monolithic nanofibers having 50% drug content exhibit efficient entrapment, wherein rapid dissolution is achieved within 30 min. The initial burst of LZM from the nanofiber was reduced as the LZM content was lowered. The initial dissolution is greatly influenced by the choice of PVA grade used; fully hydrolyzed PVA nanofibers demonstrate controlled release due to the reduced water solubility of PVA. Furthermore, coaxial electrospinning, which creates core-shell nanofibers with polycaprolactone as a controlled release layer, enables sustained LZM release over an extended period. This study confirms a correlation between PVA characteristics and controlled drug release and provides valuable insights into tailoring nanofiber properties for pharmaceutical applications.

Polyurethane foam dressing with non-adherent membrane improves negative pressure wound therapy in pigs.

OBJECTIVE: Negative pressure wound therapy (NPWT) is considered to be an effective technique to promote the healing of various wounds. The aim of this study was to evaluate different wound dressings combined with NPWT in treating wounds in Wuzhishan pigs. METHOD: Excisions were made in the backs of the pigs and were covered with polyvinyl alcohol (PVA) dressing, polyurethane (PU) dressing or PU dressing with non-adherent membrane (PU-non-ad). NPWT was applied to the wound site. In the control group, basic occlusive dressing (gauze) without NPWT was applied. On days 0, 3, 7, 14, 21 and 28 post-surgery, the wound size was measured during dressing change, and wound healing rate (WHR) was calculated. In addition, blood perfusion within 2cm of the surrounding wound was measured by laser doppler flowmetry. Dressing specimen was collected and microbiology was analysed. Granulation tissues from the central part of the wounds were analysed for histology, vascular endothelial growth factor (VEGF) and cluster of differentiation 31 (CD31) mRNA expression. RESULTS: The PU-non-ad-NPWT significantly (p<0.01) accelerated wound healing in the pigs. Further pathological analysis revealed that the non-adherent membrane effectively protected granulation tissue formation in PU-NPWT treated wounds. The blood perfusion analysis suggested that the non-adherent membrane improved the blood supply to the wound area. Microbiological analysis showed that non-adherent membrane decreased the bacterial load in the PU-NPWT dressing. VEGF and CD31 mRNA expression was upregulated in the wound tissue from the PU-non-ad-NPWT treated groups. CONCLUSION: In this study, the PU dressing with non-adherent membrane was an ideal dressing in NPWT-assisted wound healing.

Excellent Antibacterial Properties of Silver/Silica-Chitosan/Polyvinyl Alcohol Transparent Film.

Transparent films with excellent antibacterial properties and strong mechanical properties are highly sought after in packaging applications. In this study, Ag/SiO2 nanoparticles were introduced into a mixed solution of chitosan (CS) and polyvinyl alcohol (PVA) and a Ag/SiO2-CS-PVA transparent film was developed. The excellent properties of the film were confirmed by light transmittance, water contact angle tests and tensile tests. In addition, for the antibacterial test, the antibacterial properties of the sample against Gram-negative bacteria (Escherichia coli) and Gram-positive bacteria (Staphylococcus aureus) were explored, and the average size of the bacteriostatic circle was measured by the cross method. The final results show that Ag/SiO2-CS-PVA transparent film has the advantages of good antibacterial properties, high transparency and high mechanical strength.

Novel Bioplastic Based on PVA Functionalized with Anthocyanins: Synthesis, Biochemical Properties and Food Applications.

Over the last ten years, researchers' efforts have aimed to replace the classic linear economy model with the circular economy model, favoring green chemical and industrial processes. From this point of view, biologically active molecules, coming from plants, flowers and biomass, are gaining considerable value. In this study, firstly we focus on the development of a green protocol to obtain the purification of anthocyanins from the flower of Callistemon citrinus, based on simulation and on response surface optimization methodology. After that, we utilize them to manufacture and add new properties to bioplastics belonging to class 3, based on modified polyvinyl alcohol (PVA) with increasing amounts from 0.10 to 1.00%. The new polymers are analyzed to monitor morphological changes, optical properties, mechanical properties and antioxidant and antimicrobial activities. Fourier transform infrared spectroscopy (FTIR) spectra of the new materials show the characteristic bands of the PVA alone and a modification of the band at around 1138 cm-1 and 1083 cm-1, showing an influence of the anthocyanins' addition on the sequence with crystalline and amorphous structures of the starting materials, as also shown by the results of the mechanical tests. These last showed an increase in thickening (from 29.92 µm to approx. 37 µm) and hydrophobicity with the concomitant increase in the added anthocyanins (change in wettability with water from 14° to 31°), decreasing the poor water/moisture resistance of PVA that decreases its strength and limits its application in food packaging, which makes the new materials ideal candidates for biodegradable packaging to extend the shelf-life of food. The functionalization also determines an increase in the opacity, from 2.46 to 3.42 T%/mm, the acquisition of antioxidant activity against 2,2-diphenyl-1-picrylhdrazyl and 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) radicals and, in the ferric reducing power assay, the antimicrobial (bactericidal) activity against different Staphylococcus aureus strains at the maximum tested concentration (1.00% of anthocyanins). On the whole, functionalization with anthocyanins results in the acquisition of new properties, making it suitable for food packaging purposes, as highlighted by a food fresh-keeping test.

Enhancement of Solubility, Stability, Cellular Uptake, and Bioactivity of Curcumin by Polyvinyl Alcohol.

The biological activities and related mechanisms of curcumin, a major polyphenolic compound in turmeric, the rhizome of Curcuma longa, have been extensively investigated. Due to its poor solubility in water, the analysis of curcumin's biological activities is limited in most aqueous experimental systems. In the present study, the effects of polyvinyl alcohol (PVA), a dietary-compatible vehicle, on the solubility, stability, cellular uptake, and bioactivities of curcumin were investigated. Curcumin solubility was improved significantly by PVA; the color intensity of curcumin aqueous solution in the presence of PVA increased concentration-dependently with its peak shift to a shorter wavelength. Improved suspension stability and photostability of curcumin in an aqueous solution were also observed in the presence of PVA, even at 62.5 µg/mL. The scavenging activities of curcumin against DPPH, ABTS, AAPH radicals, and nitric oxide were enhanced significantly in the presence of PVA. PVA at 250 µg/mL also significantly enhanced the cytotoxic activity of curcumin against both HCT 116 colon cancer and INT 407 (HeLa-derived) embryonic intestinal cells by reducing the IC50 from 16 to 11 µM and 25 to 15 µM, respectively. PVA improved the cellular uptake of curcumin in a concentration-dependent manner in INT 407 cells; it increased the cellular levels more effectively at lower curcumin treatment concentrations. The present results indicate that PVA improves the solubility and stability of curcumin, and changes in these chemical behaviors of curcumin in aqueous systems by PVA could enhance the bioavailability and pharmacological efficacy of curcumin.