Intrinsic Water Transport in Moisture-Capturing Hydrogels.

Moisture-capturing hydrogels have emerged as attractive sorbent materials capable of converting ambient humidity into liquid water. Recent works have demonstrated exceptional water capture capabilities of hydrogels while simultaneously exploring different strategies to accelerate water capture and release. However, on the material level, an understanding of the intrinsic transport properties of moisture-capturing hydrogels is currently missing, which hinders their rational design. In this work, we combine absorption and desorption experiments of macroscopic hydrogel samples in pure vapor with models of water diffusion in the hydrogels to demonstrate the first measurements of the intrinsic water diffusion coefficient in hydrogel-salt composites. Based on these insights, we pattern hydrogels with micropores to significantly decrease the required absorption and desorption times by 19% and 72%, respectively, while reducing the total water capacity of the hydrogel by only 4%. Thereby, we provide an effective strategy toward hydrogel material optimization, with a particular significance in pure-vapor environments.

Novel air-liquid interface culture model to investigate stiffness-dependent behaviors of alveolar epithelial cells.

Pulmonary alveoli are functional units in gas exchange in the lung, and their dysfunctions in lung diseases such as interstitial pneumonia are accompanied by fibrotic changes in structure, elevating the stiffness of extracellular matrix components. The present study aimed to test the hypothesis that such changes in alveoli stiffness induce functional alteration of epithelial cell functions, exacerbating lung diseases. For this, we have developed a novel method of culturing alveolar epithelial cells on polyacrylamide gel with different elastic modulus at an air-liquid interface. It was demonstrated that A549 cells on soft gels, mimicking the modulus of a healthy lung, upregulated mRNA expression and protein synthesis of surfactant protein C (SFTPC). By contrast, the cells on stiff gels, mimicking the modulus of the fibrotic lung, exhibited upregulation of SFTPC gene expression but not at the protein level. Cell morphology, as well as cell nucleus volume, were also different between the two types of gels.

Residual protein analysis by SDS-PAGE in clinically manufactured BM-MSC products.

Residual substances that are considered hazardous to the recipient must be removed from final cellular therapeutic products manufactured for clinical purposes. In doing so, quality rules determined by competent authorities (CAs) for the clinical use of tissue- and cell-based products can be met. In our study, we carried out residual substance analyses, and purity determination studies of trypsin and trypsin inhibitor in clinically manufactured bone marrow-derived mesenchymal stromal/stem cell products, using the sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) method. Despite being a semiquantitative method, SDS-PAGE has several benefits over other methods for protein analysis, such as simplicity, convenience of use, and affordability. Due to its convenience and adaptability, SDS-PAGE is still a commonly used method in many laboratories, despite its limits in dynamic range and quantitative precision. Our goal in this work was to show that SDS-PAGE may be used effectively for protein measurement, especially where practicality and affordability are the major factors. The results of our study suggest a validated method to guide tissue and cell manufacturing sites for making use of an agreeable, accessible, and cost-effective method for residual substance analyses in clinically manufactured cellular therapies.

Vulvar migration of injected polyacrylamide hydrogel following breast augmentation: a case report and literature review.

BACKGROUND: Vulvar migration is a rare complication of filler injection for breast augmentation, generally presenting as repeated pain and fever. We will report a case of woman with polyacrylamide hydrogel breast injection develops vulvar abscess. CASE PRESENTATION: A woman with a history of polyacrylamide hydrogel breast injection was noted to have vulvar abscess due to migration of filler materials. Filler removal surgery and vacuum sealing drainage was performed for this patient. The patient was discharged from the hospital with no further complications. After a review of pertinent literature, only four previous case reports are found. Local inflammatory response, infection, large volume injections, inframammary fold destruction, hematogenous or lymphatic migrate, trauma, gravity and external pressure could play essential parts in the migration of injected filler. CONCLUSION: Polyacrylamide hydrogel migration poses a worldwide challenge, necessitating personalized solutions. Our case study underscores the importance of comprehensive examinations for individuals with a history of filler breast injection when suspecting vulvar filler migration.

Acceleration of the biodegradation of cationic polyacrylamide by the coupling effect of thermophilic microorganisms and high temperature in hyperthermophilic composting.

As a flocculant of sewage sludge, cationic polyacrylamide (CPAM) enters the environment with sludge and exists for a long time, posing serious threats to the environment. Due to the environmental friendliness and high efficiency in the process of organic solid waste treatment, hyperthermophilic composting (HTC) has received increasing attention. However, it is still unclear whether the HTC process can effectively remove CPAM from sludge. In this study, the effects of HTC and conventional thermophilic composting (CTC) on CPAM in sludge were compared and analyzed. At the end of HTC and CTC, the concentrations of CPAM were 278.96 mg kg-1 and 533.89 mg kg-1, respectively, and the removal rates were 72.17% and 46.61%, respectively. The coupling effect of thermophilic microorganisms and high temperature improved the efficiency of HTC and accelerated the biodegradation of CPAM. The diversity and composition of microbial community changed dramatically during HTC. Geobacillus, Thermobispora, Pseudomonas, Brevundimonas, and Bacillus were the dominant bacteria responsible for the high HTC efficiency. To our knowledge, this is the first study in which CPAM-containing sludge is treated using HTC. The ideal performance and the presence of key microorganisms revealed that HTC is feasible for the treatment of CPAM-containing sludge.

Enhanced sludge dewatering using a novel synergistic iron/peroxymonosulfate-polyacrylamide method.

In the sludge dewatering process, a formidable challenge arises due to the robust interactions between extracellular polymeric substances (EPS) and bound water. This study introduces a novel, synergistic conditioning method that combines iron (Fe2+)/peroxymonosulfate (PMS) and polyacrylamide (PAM) to significantly enhance sludge dewatering efficiency. The application of the Fe2+/PMS-PAM conditioning method led to a substantial reduction in specific filtration resistance (SFR) by 82.75% and capillary suction time (CST) by 80.44%, marking a considerable improvement in dewatering performance. Comprehensive analyses revealed that pre-oxidation with Fe2+/PMS in the Fe2+/PMS-PAM process effectively degraded EPS, facilitating the release of bound water. Subsequently, PAM enhanced the flocculation of fine sludge particles resulting from the advanced oxidation processes (AOPs). Furthermore, analysis based on the Extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory demonstrated shifts in interaction energies, highlighting the breakdown of energy barriers within the sludge and a transition in surface characteristics from hydrophilic (3.79 mJ m-2) to hydrophobic (-61.86 mJ m-2). This shift promoted the spontaneous aggregation of sludge particles. The innovative use of the Flory-Huggins theory provided insights into the sludge filtration mechanism from a chemical potential perspective, linking these changes to SFR. The introduction of Fe2+/PMS-PAM conditioning disrupted the uniformity of the EPS-formed gel layer, significantly reducing the chemical potential difference between the permeate and the water in the gel layer, leading to a lower SFR and enhanced dewatering performance. This thermodynamic approach significantly enhances our understanding of sludge dewatering and conditioning. These findings represent a paradigm shift, offering innovative strategies for sludge treatment and expanding our comprehension of dewatering and conditioning techniques.

[Augmentation mammaplasty using injected polyacrylamide hydrogel: Report of a recent case and literature review]. / Mammoplastie d'augmentation par injection d'hydrogel de polyacrylamide : rapport d'un cas récent et revue de la littérature.

Polyacrylamide hydrogel (PAAG) is a filler that has been strictly prohibited in France for many years. It first appeared on the market in 1980, used as an injectable for breast and facial augmentation, mainly in Asia and Eastern Europe. Like many other materials, it has shown unfavourable results and complications due to a foreign body reaction. It was banned in 2006, but continues to be injected illegally. With the influx of migrants, we are faced with the problem of how to manage complications, which can occur more than a decade later. We report our experience of a recent case in our department that required complete removal of the product and iterative lipofilling, with a result that remains sub-optimal, and we systematically review the literature.

High-quality Agar and Polyacrylamide Tumor-mimicking Phantom Models for Magnetic Resonance-guided Focused Ultrasound Applications.

Background: Tissue-mimicking phantoms (TMPs) have been used extensively in clinical and nonclinical settings to simulate the thermal effects of focus ultrasound (FUS) technology in real tissue or organs. With recent technological developments in the FUS technology and its monitoring/guided techniques such as ultrasound-guided FUS and magnetic resonance-guided FUS (MRgFUS) the need for TMPs are more important than ever to ensure the safety of the patients before being treated with FUS for a variety of diseases (e.g., cancer or neurological). The purpose of this study was to prepare a tumor-mimicking phantom (TUMP) model that can simulate competently a tumor that is surrounded by healthy tissue. Methods: The TUMP models were prepared using polyacrylamide (PAA) and agar solutions enriched with MR contrast agents (silicon dioxide and glycerol), and the thermosensitive component bovine serum albumin (BSA) that can alter its physical properties once thermal change is detected, therefore offering real-time visualization of the applied FUS ablation in the TUMPs models. To establish if these TUMPs are good candidates to be used in thermoablation, their thermal properties were characterized with a custom-made FUS system in the laboratory and a magnetic resonance imaging (MRI) setup with MR-thermometry. The BSA protein's coagulation temperature was adjusted at 55°C by setting the pH of the PAA solution to 4.5, therefore simulating the necrosis temperature of the tissue. Results: The experiments carried out showed that the TUMP models prepared by PAA can change color from transparent to cream-white due to the BSA protein coagulation caused by the thermal stress applied. The TUMP models offered a good MRI contrast between the TMPs and the TUMPs including real-time visualization of the ablation area due to the BSA protein coagulation. Furthermore, the T2-weighted MR images obtained showed a significant change in T2 when the BSA protein is thermally coagulated. MR thermometry maps demonstrated that the suggested TUMP models may successfully imitate a tumor that is present in soft tissue. Conclusion: The TUMP models developed in this study have numerous uses in the testing and calibration of FUS equipment including the simulation and validation of thermal therapy treatment plans with FUS or MRgFUS in oncology applications.

"Salting out" in Hofmeister Effect Enhancing Mechanical and Electrochemical Performance of Amide-based Hydrogel Electrolytes for Flexible Zinc-Ion Battery.

With the development of flexible and wearable electronic devices, it is a new challenge for polymer hydrogel electrolytes to combine high mechanical flexibility and electrochemical performance into one membrane. In general, the high content of water in hydrogel electrolyte membranes always leads to poor mechanical strength, and limits their applications in flexible energy storage devices. In this work, based on the "salting out" phenomenon in Hofmeister effect, a kind of gelatin-based hydrogel electrolyte membrane is fabricated with high mechanical strength and ionic conductivity by soaking pre-gelated gelatin hydrogel in 2 m ZnSO4 aqueous. Among various gelatin-based electrolyte membranes, the gelatin-ZnSO4 electrolyte membrane delivers the "salting out" property of Hofmeister effect, which improves both the mechanical strength and electrochemical performance of gelatin-based electrolyte membranes. The breaking strength reaches 1.5 MPa. When applied to supercapacitors and zinc-ion batteries, it can sustain over 7500 and 9300 cycles for repeated charging and discharging processes. This study provides a very simple and universal method to prepare polymer hydrogel electrolytes with high strength, toughness, and stability, and its applications in flexible energy storage devices provide a new idea for the construction of secure and stable flexible and wearable electronic devices.

Evolution of the theoretical description of the isoelectric focusing experiment: I. The path from Svensson's steady-state model to the current two-stage model of isoelectric focusing.

In 1961, Svensson described isoelectric focusing (IEF), the separation of ampholytic compounds in a stationary, natural pH gradient that was formed by passing current through a sucrose density gradient-stabilized ampholyte mixture in a constant cross-section apparatus, free of mixing. Stable pH gradients were formed as the electrophoretic transport built up a series of isoelectric ampholyte zones-the concentration of which decreased with their distance from the electrodes-and a diffusive flux which balanced the generating electrophoretic flux. When polyacrylamide gel replaced the sucrose density gradient as the stabilizing medium, the spatial and temporal stability of Svensson's pH gradient became lost, igniting a search for the explanation and mitigation of the loss. Over time, through a series of insightful suggestions, the currently held notion emerged that in the modern IEF experiment-where the carrier ampholyte (CA) mixture is placed between the anolyte- and catholyte-containing large-volume electrode vessels (open-system IEF)-a two-stage process operates that comprises a rapid first phase during which a linear pH gradient develops, and a subsequent slow, second stage, during which the pH gradient decays as isotachophoretic processes move the extreme pI CAs into the electrode vessels. Here we trace the development of the two-stage IEF model using quotes from the original publications and point out critical results that the IEF community should have embraced but missed. This manuscript sets the foundation for the companion papers, Parts 2 and 3, in which an alternative model, transient bidirectional isotachophoresis is presented to describe the open-system IEF experiment.

A Dormant Reagent Reaction-Diffusion Method for the Generation of Co-Fe Prussian Blue Analogue Periodic Precipitate Particle Libraries.

Liesegang patterns that develop as a result of reaction-diffusion can simultaneously form products with slightly different sizes spatially separated in a single medium. We show here a reaction-diffusion method using a dormant reagent (citrate) for developing Liesegang patterns of cobalt hexacyanoferrate Prussian Blue analog (PBA) particle libraries. This method slows the precipitation reaction and produces different-sized particles in a gel medium at different locations. The gel-embedded particles are still catalytically active. Finally, the applicability of the new method to other PBAs and 2D systems is presented. The method proves promising for obtaining similar inorganic framework libraries with catalytic abilities.

Thermodynamic and kinetic analysis on oligomeric protein dissociation using high-pressure native PAGE velocity method.

High pressure is known to dissociate several oligomeric proteins, and regarded as an important tool to shift the oligomerization equilibrium. Native polyacrylamide gel electrophoresis (native PAGE) at high pressure can characterize the dissociates and clearly discriminate the aggregates. However, a band smearing of migration profiles often hinders more detailed analyses (Miwa et al., High Pressure Res. (2019) 39, 218-224). In this paper, we focused on the band smearing dependent on the migration velocity so as to extract both thermodynamic and kinetic parameters. We systematically perturbed the migration velocity by changing the gel concentration and carried out numerical analysis for a series of the migration profiles based on a simple dissociation reaction scheme with limited thermodynamic and kinetic parameters. Then, complete volumetric properties on oligomerization process can be available. We term the present analysis method as a high-pressure native PAGE velocity method. We also report the application of this method to revisit the pressure dissociation of tetrameric lactate dehydrogenase (LDH) from pig heart.

Proteolytic polymer: polyacrylamides functionalized with amino acids cleave bovine and human serum albumins.

Polyacrylamides with various compositions of serine, aspartic acid, and histidine, which are the amino acids involved in the catalytic triad of natural serine protease chymotrypsin, were synthesized and their protein cleavage activity was investigated. SDS-PAGE analysis showed that some of the synthesized ternary copolymers showed cleavage activity against bovine and human serum albumins. Polyacrylamides incorporating a single type of amino acid were also able to cleave the protein substrates. These homopolymers exhibited unique cleavage profiles and pH and temperature sensitivities that differed from those of α-chymotrypsin. The results indicate the potential of polymers functionalized with amino acids as proteolytic artificial enzymes.

Quality of life and sexual function after tension-free vaginal tape and polyacrylamide hydrogel injection for primary stress urinary incontinence: 3-year follow-up from a randomized clinical trial.

INTRODUCTION AND HYPOTHESIS: To assess quality of life (QoL) and sexual function outcomes at 3 years after tension-free vaginal tape (TVT) and polyacrylamide hydrogel injection (PAHG) for stress urinary incontinence (SUI). METHODS: In this randomized trial comparing TVT (n = 104) and PAHG (n = 108), we assessed changes in QoL and sexuality using the Urogenital Distress Inventory (UDI-6), Incontinence Impact Questionnaire, Short Form (IIQ-7), Pelvic Organ Prolapse/Urinary Incontinence Sexual Questionnaire (PISQ-12) and RAND-36 Item Health Survey (RAND-36) at baseline and at 3 years. This is a secondary analysis of a randomized, noninferiority trial comparing patient satisfaction after TVT and PAHG. RESULTS: In both groups, incontinence-related QoL improved from the baseline (p < 0.00), except for difficulty emptying the bladder and pain/discomfort. Total scores of UDI-6 and IIIQ-7 were lower for TVT compared to PAHG (p < 0.00) indicating better QoL at 3 years. Urinary incontinence with sexual activity or fear of incontinence restricting sexual activity improved in both groups (p < 0.00), with higher scores for physical section subscale in PISQ-12 (p = 0.02) for TVT. Physical and social functioning (RAND-36) improved from the baseline in both groups (p < 0.01) with a better outcome in the TVT group for physical functioning (p = 0.00). CONCLUSIONS: Both TVT and PAHG improve QoL and sexual function in primary SUI with better incontinence and health-related QoL scores in the TVT group compared to the PAHG group at 3 years.

Acidovorax PSJ13, a novel, efficient polyacrylamide-degrading bacterium by cleaving the main carbon chain skeleton without the production of acrylamide.

Given the environmental challenge caused by the wide use of polyacrylamide (PAM), an environmental-friendly treatment method is required. This study demonstrates the role of Acidovorax sp. strain PSJ13 isolated from dewatered sludge in efficiently degrading PAM. To be specific, the strain PSJ13 can degrade 51.67% of PAM in 96 h (2.39 mg/(L h)) at 35 °C, pH 7.5 and 5% inoculation amount. Besides, scanning electron microscope, X-ray photoelectron spectroscopy, liquid chromatography-mass spectrometry and high-performance liquid chromatography were employed to analyze samples, and the nitrogen present in the degradation products was investigated. The results showed that the degradation of PAM by PSJ13 started from the side chain and then mainly the -C-C- main chain, which produced no acrylamide monomers. As the first study to report the role of Acidovorax in efficiently degrading PAM, this work may provide a solution for industries that require PAM management.

Probing of alpha, beta and kappa-caseins polymorphic variants in Gangatiri cow milk with the use of polyacrylamide gel electrophoresis and HRAMS.

This research communication aimed to probe the genetic polymorphisms of alpha, beta, and kappa caseins in Gangatiri cows (an indigenous Indian cattle). Detection of variants has received considerable research interest in the dairy industry and animal breeding in recent years as a source of good quality protein, but also of bioactive peptides that may be linked to health implications. The polymorphic nature of casein fractions and their association with milk production traits, composition, and quality also attracted several efforts in evaluating the allelic distribution of different casein locus as a potential dairy trait marker. Molecular techniques of polyacrylamide gel electrophoresis and high-resolution accurate mass-spectrometry have been applied to this probe. Sequence analysis of different casein types in the cows showed the presence of four specific variants.

Polyacrylamide.

The Expert Panel for Cosmetic Ingredient Safety reviewed updated information that has become available since their original assessment from 1991, along with updated information regarding product types, and frequency and concentrations of use, and reaffirmed their original conclusion that Polyacrylamide is safe as a cosmetic ingredient in the practices of use and concentration as described in this report.

Development of a Disposable Polyacrylamide Hydrogel-Based Semipermeable Membrane for Micro Ag/AgCl Reference Electrode.

Currently, Ag/AgCl-based reference electrodes are used in most electrochemical biosensors and other bioelectrochemical devices. However, standard reference electrodes are rather large and do not always fit within electrochemical cells designed for the determination of analytes in low-volume aliquots. Therefore, various designs and improvements in reference electrodes are critical for the future development of electrochemical biosensors and other bioelectrochemical devices. In this study, we explain a procedure to apply common laboratory polyacrylamide hydrogel in a semipermeable junction membrane between the Ag/AgCl reference electrode and the electrochemical cell. During this research, we have created disposable, easily scalable, and reproducible membranes suitable for the design of reference electrodes. Thus, we came up with castable semipermeable membranes for reference electrodes. Performed experiments highlighted the most suitable gel formation conditions to achieve optimal porosity. Here, Cl- ion diffusion through the designed polymeric junctions was evaluated. The designed reference electrode was also tested in a three-electrode flow system. The results show that home-built electrodes can compete with commercial products due to low reference electrode potential deviation (~3 mV), long shelf-life (up to six months), good stability, low cost, and disposability. The results show a high response rate, which makes in-house formed polyacrylamide gel junctions good membrane alternatives in the design of reference electrodes, especially for these applications where high-intensity dyes or toxic compounds are used and therefore disposable electrodes are required.

Polyacrylamide Hydrogel Containing Calendula Extract as a Wound Healing Bandage: In Vivo Test.

Hydrogel is a biomaterial widely used in several areas of industry due to its great biocompatibility and adaptability to biological tissues. In Brazil, the Calendula plant is approved by the Ministry of Health as a medicinal herb. It was chosen to be incorporated in the hydrogel formulation because of its anti-inflammatory, antiseptic and healing effects. This study synthesized polyacrylamide hydrogel containing calendula extract and evaluated its efficiency as a bandage for wound healing. The hydrogels were prepared using free radical polymerization and characterized by Scanning Electron Microscopy, swelling analysis and mechanical properties by texturometer. The morphology of the matrices showed large pores and foliaceous structure. In vivo testing, as well as the evaluation of acute dermal toxicity, was conducted using male Wistar rats. The tests indicated efficient collagen fiber production, improved skin repair and no signs of dermal toxicity. Thus, the hydrogel presents compatible properties for the controlled release of calendula extract used as a bandage to promote cicatrization.

Insight into the purification of algael water by a novel flocculant with enhanced branched nanochitosan structure.

For improving inadequate nanostructural stability and promote algal removal efficiency, a novel nanochitosan-grafted flocculant (PAD-g-MNC) with an enhanced branched nanostructure and high molecular weight (MW) was fabricated via maleic anhydride acylation polymerization. Characterization results verified the successful synthesis of the flocculant and the formation of an irregular particle nanostructure. PAD-g-MNC exhibited superior algal and extracellular organic matter (EOM) removal and obtained the turbidity and chlorophyll-a removal rates of 93.46%-95.39% and 95.10%-97.31%, respectively, at the dosage of 4-5 mg L-1. The growth rate, strength factor, and recovery factor of algal flocs flocculated by PAD-g-MNC were 90.36, 0.63, and 0.27 (100 rpm), respectively, and were higher than other flocculants prepared through conventional methods. Results indicated that the high intrinsic viscosity and stability branched nanostructure promoted the formation of stable flocs and regeneration ability of flocs. MW distribution and three-dimensional fluorescence analyses revealed that the special structure of PAD-g-MNC was beneficial to the removal of tryptophan-like proteins in EOM. Strong adsorption-adhesion and bridging-netting effects of the nanostructure chain were the dominated mechanisms in the improvement of flocculation efficiency. This study provided theoretical and experimental guidance for the design of flocculants with superior performance and efficient algal water purification performance.