PVA Hydrogel Research Articles

Antimicrobial PVA Hydrogels with Tunable Mechanical Properties and Antimicrobial Release Profiles.

Hydrogels are broadly employed in wound healing applications due to their high water content and tissue-mimicking mechanical properties. Healing is hindered by infection in many types of wound, including Crohn's fistulas, tunneling wounds that form between different portions of the digestive system in Crohn's disease patients. Owing to the rise of drug-resistant infections, alternate approaches are required to treat wound infections beyond traditional antibiotics. To address this clinical need, we designed a water-responsive shape memory polymer (SMP) hydrogel, with natural antimicrobials in the form of phenolic acids (PAs), for potential use in wound filling and healing. The shape memory properties could allow for implantation in a low-profile shape, followed by expansion and would filling, while the PAs provide localized delivery of antimicrobials. Here, we developed a urethane-crosslinked poly(vinyl alcohol) hydrogel with cinnamic (CA), p-coumaric (PCA), and caffeic (Ca-A) acid chemically or physically incorporated at varied concentrations. We examined the effects of incorporated PAs on antimicrobial, mechanical, and shape memory properties, and on cell viability. Materials with physically incorporated PAs showed improved antibacterial properties with lower biofilm formation on hydrogel surfaces. Both modulus and elongation at break could be increased simultaneously in hydrogels after both forms of PA incorporation. Cellular response in terms of initial viability and growth over time varied based on PA structure and concentration. Shape memory properties were not negatively affected by PA incorporation. These PA-containing hydrogels with antimicrobial properties could provide a new option for wound filling, infection control, and healing. Furthermore, PA content and structure provide novel tools for tuning material properties independently of network chemistry, which could be harnessed in a range of materials systems and biomedical applications.

Highly conductive, anti-freezing, and adhesive hydrogels containing pores constructed by cation–dipole interactions

The low ionic conductivity of most hydrogels limits their application in various fields. Boosting ion conductivity in anion exchange membranes (AEMs) using dipole-ion interactions (electrostatic attraction between anions and neutral dipole molecules) with exceptional interaction energies of 20 to 200 kJ mol−1 is the best way to create ion channels in anion exchange membranes (AEMs). In this study, intending to increase the ionic conductivity of hydrogels, the antifreeze crosslinked PVA/PVP hydrogels (5, 10, and 15% Cr-PVA) were prepared using 1,10-dibromodecane (DBD) to crosslink PVA and PVP via SN2 reaction to create multiple pores morphology in the hydrogels by cation-dipole interactions. Moreover, the prepared hydrogels contain cationic groups facilitating ion transport through the hopping mechanism. There was a significant difference in ionic conductivity between the 10% Cr-PVA hydrogel (2.63 S m−1) and the PVA hydrogel (0.76 S m−1) at room temperature due to the multiple pores created with cation-dipole interaction. Despite excellent mechanical properties, 10% Cr-PVA at −20 °C (1.25 S m−1) has a higher ionic conductivity than most antifreeze conductive hydrogels. Eventually, the 10% Cr-PVA hydrogel with gauge factor 1.97 demonstrated the desired sensitive response performance for sensor applications.

A spatiotemporal controllable crosslinking route for preparing tough tissue-like anisotropic PVA hydrogel

Highly ordered and multi-layered assembly structures endow biological tissues with excellent and unique mechanical properties. Up to now, it is difficult to prepare artificial materials with the tissue-like structures through the traditional gelation routes for the lack of a spatiotemporal controllable cross-linking strategy. Here we propose a dynamic borate ester bonds assisted method to realize the spatiotemporal controllable cross-linking of PVA hydrogel, which make it feasible to prepare biomimetic anisotropic PVA hydrogel architectures.In this work, the directional alignment and re-crosslinking of the polymer chains can be performed as needed. The fracture strength of the obtained anisotropic hydrogel can reach ∼8.0 MPa, which is about 34 and 12 times that of the hydrogels obtained by freezing-thawing and salting-out respectively. Highly ordered structure and good anti-swelling of the hydrogels obtained by this method are determined by Polarizing microscope, X-ray diffraction and Scanning electron microscope. Various tissue-like hydrogels with hierarchical uniaxial or multi-layered assembly are prepared with this method. This study provides a facile, friendly and spatiotemporal controllable route to prepare tough biomimetic hydrogel architectures, which have potential application in biomedical engineering or soft machines.

Reinforcement effect of multilayer graphene in PVA hydrogel during large strain tension

Reinforcement effect of multilayer graphene in PVA hydrogel during large strain tension

A follow-up study on “A sensitive determination of morphine in plasma using AuNPs@UiO-66/PVA hydrogel as an advanced optical scaffold”

A double solvent-assisted approach was developed for the preparation of AuNPs@UiO-66 based polyvinyl alcohol hydrogel nanocomposite and evaluated its potential as a nanoprobe for the determination of morphine. The characterization and morphology of the synthesized platform were studied and performance comparison for morphine determination was done between the synthesized scaffold and the reported one in our previous work and discussed in detail. Due to the encapsulation of AuNPs inside UiO-66 in a double solvent-assisted approach, no energy transfer was performed with UiO-66 and finally, morphine could not bind with AuNPs. Given these values, such a hydrogel-based matrix prepared with different methodologies with the same thermal stability demonstrates dissimilar potential toward morphine determination in biological samples.

V05-11 DEVELOPMENT OF PERFUSED ROBOT-ASSISTED PARTIAL NEPHRECTOMY PROCEDURAL SIMULATION PLATFORM FOR SINGLE PORT, RETROPERITONEAL APPROACHES

You have accessJournal of UrologyCME1 Apr 2023V05-11 DEVELOPMENT OF PERFUSED ROBOT-ASSISTED PARTIAL NEPHRECTOMY PROCEDURAL SIMULATION PLATFORM FOR SINGLE PORT, RETROPERITONEAL APPROACHES Nathan Schuler, Lauren Shepard, Craig Rogers, Riccardo Autorino, Sammy Elsamara, Simone Crivellaro, Jean Joseph, and Ahmed Ghazi Nathan SchulerNathan Schuler More articles by this author , Lauren ShepardLauren Shepard More articles by this author , Craig RogersCraig Rogers More articles by this author , Riccardo AutorinoRiccardo Autorino More articles by this author , Sammy ElsamaraSammy Elsamara More articles by this author , Simone CrivellaroSimone Crivellaro More articles by this author , Jean JosephJean Joseph More articles by this author , and Ahmed GhaziAhmed Ghazi More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003263.11AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Retroperitoneal robot assisted partial nephrectomy (RAPN) has shown restricted diffusion, limited to experienced surgeons at select institutions]. However, the recent introduction of the da Vinci single port (SP) surgical platform for RAPN with its slender profile is ideal for navigating narrow spaces. We have previously developed and validated a realistic, perfused hydrogel platform for transperitoneal RAPN robotic surgery as an adequate training tool. Our objective was to develop a similar platform using the same methodology. METHODS: A contoured box was designed to replicate the intraabdominal space surrounding the kidney, emphasizing realistic responses to initial incisions, balloon dilatation, and robot docking, then subsequently 3D printed. Patient-specific renal tissue phantoms and supporting structures were created using previously validated methods. Previous work with tensile testing on PVA hydrogels validated their ability to mimic the physical properties of renal tissue. The phantom was wrapped in a simulated Gerota’s Fascia, attached to a PVA “muscle” sheet, and connected to a hydrogel AA and IVC. The completed model was fixed to the inner contour of the 3D printed body cavity section, which was then covered with a hydrogel abdominal wall with a simulated peritoneal pouch, containing simulated bowels. Experts at the University of Rochester, Cleveland clinic and Henry ford hospitals tested the model during scheduled simulation events. 6 experts with >50 case experience in Single port robotic surgery and >1000 multiport robotic cases completed a survey to evaluate the realism and educational effectiveness of this model. RESULTS: Respondents completed surveys on the novelty and effectiveness of the platform. Agreement on simulator novelty was unanimously positive (100% agree or better) (Figure 1a). Performance evaluations reached a minimum of 80% agreement for all categories, with 100% of feedback rated as neutral or better. (Figure 1b). CONCLUSIONS: This realistic simulation procedural platform for robot assisted single port retroperitoneal renal surgery provides a suitable training medium for training and experienced urologists to improve the skills required to adopt this approach. Source of Funding: None © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e427 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Nathan Schuler More articles by this author Lauren Shepard More articles by this author Craig Rogers More articles by this author Riccardo Autorino More articles by this author Sammy Elsamara More articles by this author Simone Crivellaro More articles by this author Jean Joseph More articles by this author Ahmed Ghazi More articles by this author Expand All Advertisement PDF downloadLoading ...

Phase Inversion-Based foam hydrogels for highly efficient Solar-Powered interfacial desalination

Innovative materials are required to promote the development of solar-powered interfacial desalination and purification technologies to address global freshwater scarcities. To this end, evaporators using polymeric hydrogels have been widely studied. However, these systems are slow, energy-intensive, complex, and difficult to operate. New strategies are in urgent need. The present work employs polymeric phase inversion to develop poly (vinyl alcohol) (PVA)-based foam hydrogels, wherein the air bubble phase served as the matrix and cross-linked PVA hydrogel acted as the dispersed phase. In addition, we utilize Ti3C2Tx nanosheets-based MXene as the photothermal agent to facilitate the fabrication of hierarchical pore-in-pore structures. The prepared PVA/MXene foam hydrogels exhibit > 95% porosity, as well as high compressibility (>7000 cycles) and very rapid water transport. Importantly, these materials also exhibit remarkably low water evaporation enthalpies. Combined with a new heat supply model, those foam hydrogels achieve an evaporation rate of 4.1 ± 0.1 kg m−2h−1 with energy efficiency up to 128.8% ± 2.0% under 1 sun irradiation, which is the highest value for MXene-based nanocomposites reported so far. This study demonstrates a significant advancement in solar desalination system by combining phase inversion to make innovative foam materials with optimal external heat management.

Preparation of salt-tolerant chitosan hydrogels and their anti-biofouling behavior study

The hydration of wettable materials can help to improve their anti-biofouling effect, but their hydration stability under high salinity conditions is a challenge considering the future applications in natural marine environments. Inspired by the self-cleaning properties of crustaceans, chitosan (CS)/Poly (vinyl alcohol) (PVA) hydrogels have been prepared, and their anti-biofouling and salt tolerant mechanism were deeply investigated using surface analysis and molecular dynamics simulation. Interestingly, it is found that CS/PVA hydrogels can be controllably triggered at a low pH, and they can self-adjust to enhance anti-biofouling performance following the changes of environmental conditions. The hydration of CS/PVA hydrogels is enhanced in seawater because of a low salt sensitivity factor (f) of these hydrogels with a value of less than 0. Super hydrophilicity of CS/PVA hydrogels makes water drop achieve super spreading within 66.5 ms. Compared to PVA hydrogels, almost no crude oil, protein and algae can adhere to the surface of the prepared CS/PVA (0.2:1) hydrogel. The field tests in the south sea of China also demonstrate that CS/PVA (0.2:1) hydrogel has an excellent anti-biofouling ability after 6 months of testing. The anti-biofouling mechanism is also discussed according to the experimental results and molecular dynamics simulation.

Stretchable Superhydrophobic Supercapacitor with Excellent Self-Healing Ability

Flexible supercapacitors have attracted widespread attention due to the rapid development of wearable electronics. Nevertheless, most supercapacitors will degrade after being stretched and cannot work underwater. Here, a new kind of stretchable superhydrophobic supercapacitor was proposed. On the basis of the freeze–thaw treatment of PVA hydrogel, carrageenan and carbon nanotubes (CNTs) were further introduced to construct a triple network hydrogel that achieved self-healing, high elasticity, and stretchability simultaneously. Then, hydrophobic modified CNTs and NiO/CoO nanoparticles were sprayed onto the surface of the hydrogel to construct electrodes. The energy storage performance was improved by combining pseudocapacitive (CoO and NiO) and electric double-layer capacitive (MWCNT) behaviors. The superhydrophobic supercapacitor has excellent flexibility, self-healing, and self-cleaning properties. Furthermore, it can maintain superhydrophobic and good energy storage performance even after being stretched 400%, abraded 65 cycles, and cut 20 times. Owing to superhydrophobicity, this supercapacitor would have a bright application for underwater workings.

Development of Superpermeable Wood-Based Forward Osmosis Membranes

Novel lignin-based membranes with excellent water permeability and salt rejection characteristics were developed for forward osmosis (FO) processes. The fabricated membranes are composed of three layers: (i) a bottom layer of nanofibrous electrospun sulfonated kraft lignin (SKL) (70 wt %) and poly(vinyl alcohol) (PVA) (30 wt %), (ii) an intermediate layer of PVA-glutaraldehyde (GA) hydrogel, and (iii) a top thin film of a selective polyamide (PA) layer. We coated the SKL-PVA support surface with four different PVA hydrogel concentrations (0.25, 0.5, 1, and 2 wt %). Increasing the concentration of the PVA hydrogel, the thickness of the deposited layer was increased accordingly. After forming the PA layer on top of the PVA hydrogel layer by the interfacial polymerization reaction, lignin-based thin film composite (LTFC-X) membranes were obtained, in which X denotes the PVA hydrogel concentration. According to the cross-sectional TEM images, the thickness of the deposited PA layer dropped from 450 nm on the LTFC-0.25 membrane to less than 60 nm in the LTFC-1 membrane. However, a further increase in the PVA hydrogel concentration enhanced the PA layer thickness to over 250 nm. Among all synthesized membranes, the LTFC-0.5 membrane demonstrated the lowest structural parameter (S) of 191.67 ± 5.88 μm, resulting in a minimal internal concentration polarization in this membrane. The FO performances of membranes were evaluated in two different configurations: the active PA layer facing the feed solution (ALFS) and the PA layer facing the draw solution (ALDS). The LTFC-0.5 membrane provided maximum water flux (Jw) in both ALDS (61.33 ± 2.85 LMH) and ALFS (56.60 ± 2.99 LMH) modes. The LTFC-0.5 membrane also showed the lowest specific salt flux (Js/Jw) of 0.087 ± 0.004 g/L among all fabricated membranes in the ALDS mode. However, the LTFC-1 membrane provided the best performance in the ALFS mode with a minimum Js/Jw value of 0.090 ± 0.011 g/L.

Preparation and characterization of PVA/Chitosan cross-linked 3D scaffolds for liver tissue engineering

In this study, chitosan, and PVA are used to fabricate scaffolds using the 3D bioprinting technique for liver tissue engineering. PVA and chitosan hydrogels are cross-linked by the glutaraldehyde, genipin, and freeze–thaw methods. Hydrogels are then characterized by different techniques such as SEM, FTIR, swelling ratio, and biodegradability tests. Further, bioink is prepared using Chitosan/PVA hydrogel and HepG2 cells. Gels cross-linked by genipin were mechanically stable and also demonstrated higher cell viability compared to gels cross-linked by other methods. Overall, the chitosan-PVA cross-linked 3D hydrogels indicated substantial promise for liver tissue engineering.

Surface Modification of Transition Metal Dichalcogenide Nanosheets for Intrinsically Self-Healing Hydrogels with Enhanced Mechanical Properties.

Nanocomposites with enhanced mechanical properties and efficient self-healing characteristics can change how the artificially engineered materials' life cycle is perceived. Improved adhesion of nanomaterials with the host matrix can drastically improve the structural properties and confer the material with repeatable bonding/debonding capabilities. In this work, exfoliated 2H-WS2 nanosheets are modified using an organic thiol to impart hydrogen bonding sites on the otherwise inert nanosheets by surface functionalization. These modified nanosheets are incorporated within the PVA hydrogel matrix and analyzed for their contribution to the composite's intrinsic self-healing and mechanical strength. The resulting hydrogel forms a highly flexible macrostructure with an impressive enhancement in mechanical properties and a very high autonomous healing efficiency of 89.92%. Interesting changes in the surface properties after functionalization show that such modification is highly suitable for water-based polymeric systems. Probing into the healing mechanism using advanced spectroscopic techniques reveals the formation of a stable cyclic structure on the surface of nanosheets, mainly responsible for theimproved healingresponse. This work opens an avenue toward the development of self-healing nanocomposites where chemically inert nanoparticles participate in the healing network rather than just mechanically reinforcing the matrix by slender adhesion.

Tough and anti‐swelling γ‐polyglutamic acid/polyvinyl alcohol hydrogels for wearable sensors

AbstractHydrogels are widely used in biomedicine, wearable electronics and other fields due to their flexibility and high water content. However, hydrogels prepared by traditional methods generally suffer from swelling in humid environments, which greatly limits their development. This is because most hydrogels are prepared in a non‐swollen equilibrium state. This work introduces a method based on directional crystallization to adjust the mechanical and anti‐swelling properties of γ‐polyglutamic acid/polyvinyl alcohol (γ‐PGA/PVA) hydrogels. The results show that the directional crystallization method can effectively improve the anti‐swelling performance of the hydrogel. After the directional crystallization process for three times, the γ‐PGA/PVA hydrogel can remain stable in HCl‐Tris solution up to 2 months, indicating its good anti‐swelling properties. The morphology, structure and molecular composition of γ‐PGA/PVA hydrogels were systematically studied, and their anti‐swelling mechanism was also investigated. In addition, the γ‐PGA/PVA hydrogel exhibits good response to human motion, opening up new avenues in the field of wearable sensors.

In situ preparation of spindle calcium carbonate-chitosan/poly (vinyl alcohol) anti-biofouling hydrogels inspired by shellfish

Hydrogels have received intensive interest in the marine environment due to their excellent anti-biofouling properties. In this work, a series of spindle CaCO3-Chitosan/poly (vinyl alcohol) (SCC/PVA) hydrogels were in situ prepared inspired by the good mechanical self-cleaning and properties of seashell. The morphologies, structure and components of the prepared hydrogels were studied by SEM, FTIR spectra, XRD, TGA, and TEM. The anti-biofouling properties of the prepared hydrogels against protein, bacteria and algae were evaluated by ultrahigh-resolution fluorescence microscopy. Results indicated that chitosan can affect the growth process of CaCO3 leading to the formation of a hollow spindle structure of CaCO3. The prepared SCC/PVA hydrogels have excellent underwater superoleophobicity properties. SCC/PVA-3 hydrogel has the best superoleophobicity property with an underwater contact angle of 167.5°. The compressive strength of SCC/PVA-3 hydrogel is 25 MPa, which is attributed to the doping of SCC. Compared to PVA hydrogel, the settlement of the Navicula, Nitzschia Closterium on the surface of SCC/PVA-3 hydrogels sample decreased by approximately 94 % and 88 %, respectively. The SCC/PVA hydrogels have some antibacterial ability against E. coli. SCC/PVA-3 hydrogel can effectively inhibit the adhesion of elegans with a test time of 180 days in the South China Sea.

High-sensitivity integrated detector with nanostructured hydrogel electrode for ascorbic acid determination

This paper proposed a novel integrated detector with nanostructured hydrogel electrode (IDNHE) for ascorbic acid detection. The electrochemical detector was integrated on printed circuit board (PCB). The IDNHE employed the nanostructured multi-walled carbon nanotubes/polyaniline/polyvinyl alcohol (MWCNTs/PANI/PVA) hydrogel as the working electrode. The PVA hydrogel can not only effectively combine the PANI and substrate through hydrogen bonds, but also greatly improve the stability and durability of the detector. MWCNTs were used to fabricate the nanostructures, increasing the surface area of electrode. The detection mechanism is based on the redox reaction of PANI with ascorbic acid. The detection limit and the sensitivity of IDNHE were 0.9 μM (S/N = 3) and 161.46 mA·μM−1·cm−2, respectively. Moreover, IDNHE has a satisfactory reproducibility (RSD = 1.43 %), repeatability (RSD = 2.35 %) and long-term stability for 90 days. Therefore, this work undoubtedly provides a considerate choice for the lab on a chip, and further a promising application prospect for developing the portable real-time monitoring device.

Bibliometric Analysis on Scholarly Journals of PVA Hydrogel Membrane Using VOSviewers Software

The development of technology in this world is already developing rapidly. One of the advanced technologies that support research planning is bibliometrics. This study aims to analyze the scope of research on PVA Hydrogel Membrane using VOSviewer using bibliometric review with a mapping process to ensure that the research to be carried out has never been studied and knows the relationship of each related item. The three processes underlying the search use the keywords "chemistry, particle, PVA, and Hydrogel" namely title, abstract, and keyword. The research database is taken from google scholar. A total of 98 articles are relevant and meet the criteria. The results show that most of the studies were conducted in the 2012-2022 range. PVA and Hydrogel are so closely related to each other that they have a fairly bright density visualization. Some items are not related to the PVA Hydrogel Membrane but these items are interconnected with other items so it can be concluded that there are still many items that can be used for further research.

Production and Anti-Inflammatory Performance of PVA Hydrogels Loaded with Curcumin Encapsulated in Octenyl Succinic Anhydride Modified Schizophyllan as Wound Dressings.

Amphiphilic polysaccharides can be used as wall materials and applied to encapsulate hydrophobic active chemicals; moreover, there is significant demand for novel medical high-molecular-weight materials with various functions. In order to prepare amphiphilic schizophyllan (SPG), octenyl succinic anhydride (OSA) was chosen to synthesize OSA-modified schizophyllan (OSSPG) using an esterified reaction. The modification of OSSPG was demonstrated through FT-IR and thermal analysis. Moreover, it was found that OSSPG has a better capacity for loading curcumin, and the loading amount was 20 μg/mg, which was 2.6 times higher than that of SPG. In addition, a hydrogel made up of PVA, borax, and C-OSSPG (OSSPG loaded with curcumin) was prepared by means of the one-pot method, based on the biological effects of curcumin and the immune-activating properties of SPG. The mechanical properties and biological activity of the hydrogel were investigated. The experimental results show that the dynamic cross-linking of PVA and borax provided the C-OSSPG/BP hydrogel dressing with exceptional self-healing properties, and it was discovered that the C-OSSPG content increased the hydrogel's swelling and moisturizing properties. In fibroblast cell tests, the cells treated with hydrogel had survival rates of 80% or above. Furthermore, a hydrogel containing C-OSSPG could effectively promote cell migration. Due to the excellent anti-inflammatory properties of curcumin, the hydrogel also significantly reduces the generation of inflammatory factors, such as TNF-α and IL-6, and thus has a potential application as a wound dressing medicinal material.

High-Energy-Density Zinc–Air Microbatteries with Lean PVA–KOH–K2CO3 Gel Electrolytes

Small-scale, primary electrochemical energy storage devices ("microbatteries") are critical power sources for microelectromechanical system (MEMS)-based sensors and actuators. However, the achievable volumetric and gravimetric energy densities of microbatteries are typically insufficient for intermediate-term applications of MEMS-enabled distributed internet-connected devices. Further, in the increasing subset of Internet of Things (IoT) nodes, where actuation is desired, the peak power density of the microbattery must be simultaneously considered. Metal-air approaches to achieving microbatteries are attractive, as the anode and cathode are amenable to miniaturization; however, further improvements in energy density can be obtained by minimizing the electrolyte volume. To investigate these potential improvements, this work studied very lean hydrogel electrolytes based on poly(vinyl alcohol) (PVA). Integration of high potassium hydroxide (KOH) loading into the PVA hydrogel improved electrolyte performance. The addition of potassium carbonate (K2CO3) to the KOH-PVA gel decreased the carbonation consumption rate of KOH in the gel electrolyte by 23.8% compared to PVA-KOH gel alone. To assess gel performance, a microbattery was formed from a zinc (Zn) anode layer, a gel electrolyte layer, and a carbon-platinum (C-Pt) air cathode layer. Volumetric energy densities of approximately 1400 Wh L-1 and areal peak power densities of 139 mW cm-2 were achieved with a PVA-KOH-K2CO3 electrolyte. Further structural optimization, including using multilayer gel electrolytes and thinning the air cathode, resulted in volumetric and gravimetric energy densities of 1576 Wh L-1 and 420 Wh kg-1, respectively. The batteries described in this work are manufactured in an open environment and fabricated using a straightforward layer-by-layer method, enabling the potential for high fabrication throughput in a MEMS-compatible fashion.

Polypropylene composite hernia mesh with anti-adhesion layer composed of PVA hydrogel and liposomes drug delivery system

Polypropylene (PP) mesh has been widely used in hernia repair as prosthesis material owing to its excellent balanced biocompatibility and mechanical properties. However, abdominal adhesion between the visceral and PP mesh is still a major problem. Therefore, anti-adhesive PP mesh was designed with poly(vinyl alcohol) (PVA) hydrogel and liposomes drug delivery system. First, PVA hydrogel coating was formed on the surface of PP mesh with freezing-thawing processing cycles (FTP). Subsequently, the lyophilized PVA10-c-PP was immersed in rapamycin (RPM)-loaded liposome solution until swelling equilibrated to obtain the anti-adhesion mesh RPM@LPS/PVA10-c-PP. It was demonstrated that the hydrogel coating can stably fix on the surface of PP mesh even after immersed in PBS solution at 37 °C or 40 °C for up to 30 days. In vitro cell tests revealed the excellent cytocompatibility and the potential to inhibit cell adhesion of the modified PP mesh. Moreover, the anti-adhesive effects of the RPM@LPS/PVA10-c-PP mesh was evaluated through in vivo experiments. The RPM@LPS/PVA10-c-PP mesh exhibited less adhesion than original PP mesh throughout the duration of implantation. At 30 days, the adhesion score of RPM@LPS/PVA10-c-PP mesh was 1.37 ± 0.75, however the original PP was 3 ± 0.71. Furthermore, the results of H&E and Masson trichrome staining proved that the RPM@LPS/PVA10-c-PP mesh showed slighter inflammation response and significant looser fibrous tissue surrounded the PP filaments as compared to the native PP. The current findings manifested that this type of RPM@LPS/PVA10-c-PP might be a potential candidate for anti-adhesion treatment. Data availabilityData will be made available on request.

A nanoscale inorganic coating strategy for stabilizing hydrogel neural probes in vivo.

Hydrogels with adaptable optical and mechanical characteristics show considerable promise for light delivery in vivo with neuroengineering applications. However, the unlinked amorphous polymer chains within hydrogels can cause volumetric swelling after water absorption under physiological conditions over time. Chemically cross-linked poly(vinyl alcohol) (PVA) hydrogels showcase fatigue-resistant attributes and promising biocompatibility for the manufacture of soft neural probes. However, possible swelling of the PVA hydrogel matrix could impact the structural stability of hydrogel-based bioelectronics and their long-term in vivo functionality. In this study, we utilized an atomic layer deposition (ALD) technique to generate an inorganic, silicon dioxide (SiO2) coating layer on chemically cross-linked PVA hydrogel fibers. To evaluate the stability of SiO2-coated PVA hydrogel fibers mimicking the in vivo environment, we conducted accelerated stability tests. SiO2-coated PVA hydrogel fibers showed improved stability over a one-week incubation period under a harsh environment, preventing swelling and preserving their mechanical and optical properties compared to uncoated fibers. These SiO2-coated PVA hydrogel fibers demonstrated nanoscale polymeric crystalline domains (6.5 ± 0.1 nm), an elastic modulus of 73.7 ± 31.7 MPa, a maximum elongation of 113.6 ± 24.2%, and minimal light transmission loss (1.9 ± 0.2 dB cm-1). Lastly, we applied these SiO2-coated PVA hydrogel fibers in vivo to optically activate the motor cortex of transgenic Thy1::ChR2 mice during locomotor behavioral tests. This mouse cohort was genetically modified to express the light-sensitive ion channel, channelrhodopsin-2 (ChR2), and implanted with hydrogel fibers to deliver light to the motor cortex area (M2). Light stimulation via hydrogel fibers resulted in optogenetically modulated mouse locomotor behaviors, including increased contralateral rotation, mobility speeds, and travel distances.