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1.
Nano Lett ; 24(13): 3858-3865, 2024 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-38437505

RESUMO

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.

2.
Biochem Biophys Res Commun ; 708: 149791, 2024 05 14.
Artigo em Inglês | MEDLINE | ID: mdl-38518719

RESUMO

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.


Assuntos
Células Epiteliais Alveolares , Fibrose Pulmonar , Humanos , Células Epiteliais Alveolares/metabolismo , Pulmão/metabolismo , Alvéolos Pulmonares , Fibrose Pulmonar/metabolismo , Células Epiteliais/metabolismo , Géis/metabolismo
3.
Electrophoresis ; 45(17-18): 1606-1617, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-38687192

RESUMO

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.


Assuntos
Eletroforese em Gel de Poliacrilamida , Células-Tronco Mesenquimais , Eletroforese em Gel de Poliacrilamida/métodos , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/química , Humanos , Tripsina/metabolismo , Proteínas/análise , Reprodutibilidade dos Testes , Inibidores da Tripsina/análise , Inibidores da Tripsina/química , Células da Medula Óssea/citologia
4.
Anal Biochem ; : 115680, 2024 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-39341484

RESUMO

A time-saving, one-step polyacrylamide gel preparation method enabling simultaneous preparation of separating and stacking gels was previously reported, but the boundary between the separating and stacking gels was often not well defined. As such, determining whether the gel preparation failed is difficult before SDS-PAGE is carried out. To address this issue, a one-step polyacrylamide gel preparation method was developed in which the stacking gel is colored to allow better visualization of the border between the stacking and separating gels. This new one-step method saves time and achieves comparable performance for SDS-PAGE and western blotting to that obtained with conventional gels.

5.
Heart Vessels ; 2024 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-39017677

RESUMO

The absolute value of small dense low-density lipoprotein (sd-LDL) including small LDL (s-LDL) and very small LDL (vs-LDL) has been shown to be associated with increased incidence of atherosclerosis. However, the impact of short-timeframe increases in sd-LDL on arteriosclerosis has not yet been elucidated. Therefore, we investigated the clinical roles of ex-vivo induced sd-LDL in acute coronary syndrome (ACS) using a novel method. This is a prospective, single-blind, and observational study that screened patients who underwent coronary angiography (CAG) for the treatment of ACS or investigation of heart-failure etiology between June 2020 and April 2022 (n = 247). After excluding patients with known diabetes mellitus and advanced renal disease, the patients were further divided into the ACS (n = 34) and control (non-obstructive coronary artery, n = 34) groups. The proportion of sd-LDL (s-LDL + vs-LDL) in total lipoproteins was observed before and after 2-h incubation at 37 ℃ (to approximate physiologic conditions) using 3% polyacrylamide gel electrophoresis. The coronary plaque burden was quantified upon CAG in the ACS group. There were no significant differences between the ACS and control groups in terms of clinical coronary risk factors. The baseline of large, medium, small, and very small LDL were comparable between the two groups. Following a 2-h incubation period, significant increases were observed in the ratios of s-LDL and vs-LDL in both the ACS and control groups (ACS, p = 0.01*; control, p = 0.01*). Notably, the magnitude of increase in sd-LDL was more pronounced in the ACS group compared to the control group, with s-LDL showing a significant difference (p = 0.03*) and vs-LDL showing a tread toward significance (p = 0.08). In addition, in both groups, there was a decrease in IDL and L-LDL, while M-LDL remained unchanged. The plaque burden index and rate of short-timeframe changes in both s-LDL (p = 0.01*) and vs-LDL (p = 0.04*) before and after incubation were significantly correlated in the ACS group. The enhanced production rate of sd-LDL induced under short-term physiologic culture in an ex-vivo model was greater in patients with ACS than in the control group. The increase in sd-LDL is positively correlated with coronary plaque burden. Short-timeframe changes in sd-LDL may serve as markers for the severity of coronary artery disease.

6.
BMC Womens Health ; 24(1): 152, 2024 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-38431590

RESUMO

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.


Assuntos
Abscesso , Mamoplastia , Feminino , Humanos , Mama , Resinas Acrílicas/efeitos adversos
7.
Bioprocess Biosyst Eng ; 47(3): 403-415, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38421394

RESUMO

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.


Assuntos
Resinas Acrílicas , Compostagem , Esgotos , Esgotos/microbiologia , Temperatura , Archaea , Aceleração , Solo
8.
Aesthetic Plast Surg ; 2024 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-39317860

RESUMO

BACKGROUND: Complications often arose after polyacrylamide hydrogel (PAAG) injections for breast augmentation. This study aimed to explore the complications and clinical management of breast augmentation with PAAG. METHODS: We retrospectively analyzed the data of 135 patients who underwent breast PAAG removal from January 2011 to December 2023 in our hospital. We also comprehensively analyzed the postoperative clinical results, subsequent complications, and clinical management after PAAG injections. RESULTS: Induration and nodules (60.0%), pain (27.4%), anxiety (22.2%), migration (13.3%), asymmetry (8.1%), swelling (5.9%), infection (5.2%), calcification (3.7%), and breast cancer (BC) (3.0%) were a few complications after PAAG injections. Although breast cancer was a rare complication, it might be covered up by PAAG tissue. Eighty-eight patients had undergone PAAG removal, while 47 patients had additional breast reconstruction surgery. The post-surgical complications included PAAG residue (17.0%), skin laxity (7.4%), hemorrhage (2.2%), reoperation (1.5%), and nipple or breast asymmetry (1.5%). Additionally, the BREAST-Q scores revealed that patients with breast reconstruction had a significant better outcomes in psychosocial well-being (p < 0.001), satisfaction with breasts (p < 0.001), and sexual well-being (p = 0.008). CONCLUSION: Multiple complications could occur after PAAG injections for breast augmentation. Although rare, BC might need more clinical attention. PAAG removal could alleviate some complications, and breast reconstruction contributed to improved patient satisfaction, psychosocial well-being, and sexual well-being. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

9.
Int J Mol Sci ; 25(16)2024 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-39201558

RESUMO

Polyacrylamide (PAM) is a high-molecular-weight polymer with extensive applications. However, the inefficient natural degradation of PAM results in environmental accumulation of the polymer. Biodegradation is an environmentally friendly approach in the field of PAM treatment. The first phase of PAM biodegradation is the deamination of PAM, forming the product poly(acrylic acid) (PAA). The second phase of PAM biodegradation involves the cleavage of PAA into small molecules, which is a crucial step in the degradation pathway of PAM. However, the enzyme that catalyzes the degradation of PAA and the molecular mechanism remain unclear. Here, a novel monooxygenase PCX02514 is identified as the key enzyme for PAA degradation. Through biochemical experiments, the monooxygenase PCX02514 oxidizes PAA with the participation of NADPH, causing the cleavage of carbon chains and a decrease in the molecular weight of PAA. In addition, the crystal structure of the monooxygenase PCX02514 is solved at a resolution of 1.97 Å. The active pocket is in a long cavity that extends from the C-terminus of the TIM barrel to the protein surface and exhibits positive electrostatic potential, thereby causing the migration of oxygen-negative ions into the active pocket and facilitating the reaction between the substrates and monooxygenase PCX02514. Moreover, Arg10-Arg125-Ser186-Arg187-His253 are proposed as potential active sites in monooxygenase PCX02514. Our research characterizes the molecular mechanism of this monooxygenase, providing a theoretical basis and valuable tools for PAM bioremediation.


Assuntos
Resinas Acrílicas , Biodegradação Ambiental , Oxigenases de Função Mista , Resinas Acrílicas/química , Oxigenases de Função Mista/metabolismo , Oxigenases de Função Mista/química , Domínio Catalítico , Modelos Moleculares , Cristalografia por Raios X , Conformação Proteica
10.
J Environ Manage ; 369: 122160, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39208750

RESUMO

Anaerobic digestion provides a solution for the treatment of vegetable waste water (VWW), but there are currently limited targeted treatment methods available. Building upon previous studies, this research investigated the effects of polyacrylamide-modified magnetic micro-particles (MMP) on anaerobic digestion (AD) of VWW. Three variations of these particles were created by grafting anionic, cationic, and non-ionic polyacrylamide (PAM) onto the MMPs' surfaces, resulting in aPAM-MMP, cPAM-MMP, and nPAM-MMP, respectively. In AD experiments, the addition of aPAM-MMP notably enhanced the degradation of chemical oxygen demand (COD) in VWW. COD decreased to 1290 mg/L in the reactor with aPAM-MMP by day 12 and remained low, while the other reactors had COD concentrations of 4137.5, 5510, and 3010 mg/L on the same day, decreasing thereafter. This modification also improved the production and utilization of hydrogen gas and volatile fatty acids (VFAs), along with the conversion of methane. When tested for bioaffinity using fluorescent GFP-E.coli bacteria, the aPAM-MMP, cPAM-MMP, and nPAM-MMP demonstrated increases in fluorescence intensity by 51.66%, 36.13%, and 37.02%, respectively, compared to unmodified MMP when attached with GFP-E.coli. Further analyses of microbial community revealed that the reactor with aPAM-MMP had the highest microbial richness and enriched bacteria capable of organic matter degradation, such as Bacteroidota, Synergistota, Chloroflexi, Halobacterota phyla, and Parabacteroides, Muribaculaceae, and Azotobacter genera. In conclusion, our experiment verifies that APAM-MMP promotes anaerobic treatment of VWW and provides a novel reference point for enhancing VWW degradation.


Assuntos
Resinas Acrílicas , Verduras , Águas Residuárias , Anaerobiose , Águas Residuárias/química , Resinas Acrílicas/química , Eliminação de Resíduos Líquidos/métodos , Análise da Demanda Biológica de Oxigênio
11.
J Environ Manage ; 365: 121638, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38959766

RESUMO

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.


Assuntos
Resinas Acrílicas , Ferro , Esgotos , Eliminação de Resíduos Líquidos , Esgotos/química , Ferro/química , Resinas Acrílicas/química , Eliminação de Resíduos Líquidos/métodos , Floculação , Peróxidos/química , Oxirredução , Filtração
12.
Molecules ; 29(14)2024 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-39064826

RESUMO

In the past, polyacrylamide hydrogel was a popular choice for breast augmentation filler, and many women underwent mammoplasty with this gel. However, due to frequent complications, the use of polyacrylamide hydrogel in mammoplasty has been banned. Despite this ban, patients experiencing complications still seek medical treatment. The aim of this study was to investigate the fate of the polymer over a defined implantation period. Biopsies of breast implants were obtained from patients with 23 and 27 years of post-mammoplasty. These biopsies were meticulously purified from biological impurities and subjected to analysis using IR spectrometry, liquid chromatography-mass spectrometry, gas chromatography, and differential scanning calorimetry. The findings revealed the presence of polyacrylamide hydrogel residues, along with degradation products, within the infected material. Notably, the low-molecular-weight degradation products revealed via gas chromatography are aggressive and toxic substances capable of inducing chronic inflammation. This study sheds light on the long-term consequences of polyacrylamide hydrogel implantation, highlighting the persistence of harmful degradation products and their role in exacerbating patient complications.


Assuntos
Resinas Acrílicas , Inflamação , Humanos , Resinas Acrílicas/química , Feminino , Glândulas Mamárias Humanas/metabolismo , Glândulas Mamárias Humanas/patologia , Implantes de Mama/efeitos adversos , Adulto , Mamoplastia , Pessoa de Meia-Idade
13.
Water Sci Technol ; 89(12): 3309-3324, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-39150426

RESUMO

Polyacrylamide (PAM) in environmental water has become a major problem in water pollution management due to its high molecular mass, high viscosity and non-absorption by soil. CoFe2O4 with strong magnetic properties was prepared by solvent-thermal synthesis method and used as the catalyst for the removal on PAM in heterogeneous Electro-Fenton (EF) system. It showed that the removal efficiency of PAM by the heterogeneous EF system using CoFe2O4 catalyst was 92.01% at pH 3 after 120 min. Further studies indicated that ·OH was the most significant active species for the removal of PAM, and the contribution of ·O2- and SO4·- for the removal of PAM was less than 15%. The reusability test and XRD, XPS, FTIR analyses proved that the catalyst had good stability. After a repeated use for five times, the catalyst still had a high PAM removal rate and stable structure. The valence distribution and functional groups of the phase components of the catalyst did not change significantly before and after the reaction. The possible mechanism of catalyst activation of H2O2 was deduced by mechanism investigation. The CoFe2O4 is an efficient and promising catalyst for the removal of PAM wastewater.


Assuntos
Resinas Acrílicas , Cobalto , Compostos Férricos , Peróxido de Hidrogênio , Ferro , Resinas Acrílicas/química , Cobalto/química , Catálise , Peróxido de Hidrogênio/química , Ferro/química , Compostos Férricos/química , Poluentes Químicos da Água/química , Purificação da Água/métodos , Eliminação de Resíduos Líquidos/métodos
14.
Ann Chir Plast Esthet ; 69(2): 166-172, 2024 Mar.
Artigo em Francês | MEDLINE | ID: mdl-37741804

RESUMO

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.


Assuntos
Mamoplastia , Feminino , Humanos , Mamoplastia/métodos , Mama/cirurgia , Resinas Acrílicas/efeitos adversos , Injeções
15.
J Med Ultrasound ; 32(2): 121-133, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38882616

RESUMO

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.

16.
Small ; 19(30): e2207610, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37026666

RESUMO

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.

17.
Electrophoresis ; 44(7-8): 667-674, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36640145

RESUMO

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.


Assuntos
Misturas Anfolíticas , Isotacoforese , Concentração de Íons de Hidrogênio , Focalização Isoelétrica/métodos , Misturas Anfolíticas/química
18.
Chemistry ; 29(48): e202301261, 2023 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-37098116

RESUMO

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.

19.
Anal Biochem ; 664: 115035, 2023 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-36621706

RESUMO

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.


Assuntos
L-Lactato Desidrogenase , Proteínas , Animais , Suínos , Eletroforese em Gel de Poliacrilamida Nativa , Cinética , Termodinâmica , Eletroforese em Gel de Poliacrilamida
20.
Bioorg Med Chem ; 92: 117422, 2023 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-37523791

RESUMO

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.


Assuntos
Aminoácidos , Albumina Sérica Humana , Animais , Bovinos , Humanos , Aminoácidos/farmacologia , Aminoácidos/química , Sequência de Aminoácidos , Proteínas , Peptídeo Hidrolases , Especificidade por Substrato
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