Search Results (103)

The release of synthetic dyes into the environment through industrial wastewater represents a significant environmental concern. In this study, a hydrophobic cryogel, Poly(2-hydroxyethyl methacrylate-N-methacryloyl-L-phenylalanine), was synthesized and employed for the efficient removal of methylene blue from aqueous solutions. The cryogel exhibited a surface area of 6.834 m²/g and a water retention capacity of 218.6%. Adsorption experiments conducted under various conditions revealed a high adsorption capacity of 1304.6 mg/g for MB. Thermodynamic analyses indicated that adsorption occurs spontaneously and follows a monolayer adsorption model. The adsorption capacity increased with temperature and ionic strength, confirming that hydrophobic forces predominantly drive the interaction. Reusability tests showed that the cryogel maintained its adsorption efficiency over five consecutive adsorption–desorption cycles, with a desorption efficiency of up to 98%. These findings demonstrate that Poly(HEMA-MAPA) cryogel is a practical, reusable, and eco-friendly adsorbent for removing methylene blue, a common textile dye pollutant, from water systems. Full article

This study presents a hybrid hydrogel system designed for the targeted delivery of letrozole, a key therapeutic agent in breast cancer treatment. Letrozole-loaded poly(lactic-co-glycolic acid) (PLGA) microparticles were embedded within a poly(2-hydroxyethyl methacrylate) (pHEMA) matrix coated onto acrylamide-grafted low-density polyethylene (AAm-g-LDPE), yielding a mechanically stable system with tunable drug release. Field emission scanning electron microscopy (FE-SEM) and confocal microscopy confirmed uniform microparticle distribution. In vitro release studies in simulated uterine fluid (SUF) at 37 °C demonstrated a sustained release profile over 32 days, with a reduced initial burst effect (~15% lower than conventional PLGA systems). The system’s release kinetics followed the Higuchi model (R² = 0.803–0.996), indicating Fickian diffusion. This hybrid hydrogel offers enhanced drug stability, reduced dosing frequency, and potential for personalized hormone therapy, improving patient compliance, particularly for individuals with physical or cognitive impairments. Full article

In this project, a new class of temperature- and pH-sensitive hydrogel consisting of N-isopropyl acrylamide (NIPAM), hydroxyethyl methacrylate (HEMA), and acrylamide (AAm) was prepared via a controlled route through the reversible addition–fragmentation chain-transfer (RAFT) polymerization process. Poly(ethyleneglycol) dimethacrylate (PEG-DMA) was used as a long-chain hydrophilic and biocompatible crosslinking agent. The hydrogel structure was confirmed by different characteristic techniques such as ¹H NMR, FT-IR, and SEC, and the morphology and particle diameters were checked via the scanning electron microscopy (SEM) and dynamic light scattering (DLS) methods. Afterward, the as-prepared hydrogel, poly(NIPAM-co-HEMA-co-AAm), was loaded with doxorubicin (DOX) to be used as a temperature- and pH-triggered delivery carrier. The prepared system released DOX slowly at 37 °C and neutral pH, but increased DOX release significantly at 42 °C and acidic pH. The anti-cancer efficiencies of free DOX, hydrogel, and the DOX–hydrogel conjugate were tested in vitro using human colorectal adenocarcinoma HT-29 cell lines. Cytotoxicity evaluation of free DOX compared with the DOX–hydrogel conjugate revealed that more cancer cells were killed with increasing concentration. Moreover, the DOX-mediated apoptosis and ROS levels showed the beneficial effects of poly(NIPAM-co-HEMA-co-AAm) hydrogel for cancer drug delivery. Generally, the results suggest that this system can be a potential candidate for designing drug delivery systems. Full article

Nanocomposite hydrogels are gaining significant attention for biomedical applications in soft tissue engineering due to the increasing demand for highly flexible and durable soft polymer materials. This research paper focused on investigating and optimizing a procedure for the development of novel nanocomposite hydrogels based on poly(2-hydroxyethyl methacrylate)-co-(2-acrylamido-2-methylpropane sulfonic acid) (HEMA/AMPSA) copolymers. These hydrogels were synthesized through a grafting-through process, where the polymer network was formed using a modified clay crosslinker. The layered double hydroxide (LDH) clay modified with 3-(trimethoxysilyl)propyl methacrylate (ATPM) was synthesized using a novel recipe through a two-step procedure. The nanocomposite hydrogel compositions were optimized to achieve soft hydrogels with high flexibility. The developed materials were analyzed for their mechanical and morphological properties using tensile and compressive tests, transmission electron microscopy (TEM), scanning electron microscopy (SEM), and micro-computed tomography (micro-CT). The swelling behavior, network density, and kinetic diffusion mechanism demonstrated the specific characteristics of the materials. The modified LDH-ATPM was further characterized using Thermogravimetry (TGA), FTIR-ATR and X-ray diffraction (XRD). Biological assessments on human adipose-derived stem cells (hASCs) were essential to evaluate the biocompatibility of the nanocomposite hydrogels and their potential for soft tissue applications. Full article

Background/Objectives: Glioblastoma is the most common and lethal primary brain tumor. Patients often suffer from tumor- and treatment induced vasogenic edema, with devastating neurological consequences. Intracranial edema is effectively treated with dexamethasone. However, systemic dexamethasone requires large doses to surpass the blood brain barrier in therapeutic quantities, which is associated with significant side effects. The aim of this study was to investigate a biodegradable, dextran-hydroxyethyl methacrylate (dex-HEMA) based hydrogel, containing polymeric micelles loaded with dexamethasone and liposomes encapsulating dexamethasone phosphate for localized and prolonged delivery. Methods: Poly(ethylene glycol)-b-poly(N-2-benzoyloxypropyl methacrylamide (mPEG-b-p(HPMA-Bz)) micelles were loaded with dexamethasone and characterized. The dexamethasone micelles, together with dexamethasone phosphate liposomes, were dispersed in an aqueous dex-HEMA solution followed by radical polymerization using a photoinitiator in combination with light. The kinetics and mechanisms of drug release from this hydrogel were determined. Results: The diameter of the nanoparticles was larger than the mesh size of the hydrogel, rendering them immobilized in the polymer network. The micelles immediately released free dexamethasone from the hydrogel for two weeks. The dexamethasone phosphate loaded in the liposomes was not released until the gel degraded and intact liposomes were released, starting after 15 days. The different modes of release result in a biphasic and sequential release profile of dexamethasone followed by dexamethasone phosphate liposomes. Conclusions: The results show that this hydrogel system loaded with both dexamethasone polymeric micelles and dexamethasone phosphate loaded liposomes has potential as a local delivery platform for the sequential release of dexamethasone and dexamethasone phosphate, for the intracranial treatment of glioblastoma associated edema. Full article

A series of hydrophilic copolymers were prepared using 2-hydroxyethyl methacrylate (HEMA) and itaconic acid (IA) from free radical polymerization at different feed monomer ratios using ammonium persulfate (APS) initiators in water at 70 °C. The herbicide 2,4-dichlorophenoxy acetic acid (2,4-D) was grafted to Poly(HEMA-co-IA) by a condensation reaction. The hydrolysis of the polymeric release system, Poly(HEMA-co-IA)-2,4-D, demonstrated that the release of the herbicide in an aqueous phase depends on the polymeric system’s pH value and hydrophilic character. In addition, the swelling behavior (Wt%) was studied at different pH values using Liquid-phase Polymer Retention (LPR) in an ultrafiltration system. The acid hydrolysis of the herbicide from the conjugates follows a first-order kinetic, showing higher kinetic constants as the pH increases. The base-catalyzed hydrolysis reaction of the herbicide follows a zero-order kinetic, where the basic medium acts as a catalyst, accelerating the release rate of the herbicide and showing higher kinetic constants as the pH increases. The differences in the release rates found for the hydrogel herbicide at different pH values can be correlated with the difference in their swelling capacity, where the release rate generally increases with an increase in the swelling capacity from water solution at higher pH values. The study of the release process revealed that all samples in distilled water at a pH of 10 are representative of agricultural systems. It showed first-order swelling kinetics and an absorption capacity that conforms to the parameters for hydrogels for agricultural applications, which supports their potential for these purposes. Full article

The structural and dynamic properties of poly(2-hydroxyethyl methacrylate) (PHEMA) and poly(N-vinylpyrrolidone-co-2-hydroxyethyl methacrylate) [P(VP-co-HEMA)], dry and as hydrogels, were studied by molecular dynamics simulations. The P(VP-co-HEMA) chains differed in the number of VP mers, distributed randomly or in blocks. In all considered configurations, HEMA and VP side chains proved relatively rigid and stable. Water concentration had a significant impact on their dynamic behavior. Oxygen atoms of hydroxyl and carbonyl groups of HEMA and carbonyl groups of VP are preferred sites of hydrogen bonding with water molecules. The copolymer swelling results in diffusion channels, larger in systems with high water content. In low-hydrated materials, water shows subdiffusion, while normal diffusion predominates in the high-hydrated ones. The VP side chains in copolymers with HEMA do not enhance the mobility of water. Full article

Poly(2-hydroxyethyl methacrylate) (PHEMA) has been widely used in medical materials for several decades. However, the poor mechanical properties of this material have limited its application in the field of tissue engineering. The purpose of this study was to fabricate a scaffold with suitable mechanical properties and in vitro cell responses for soft tissue by using poly(HEMA-co-MMA) with various concentration ratios of hydroxyethyl methacrylate (HEMA) and methyl methacrylate (MMA). To customize the concentration ratio of HEMA and MMA, the characteristics of the fabricated scaffold with various concentration ratios were investigated through structural morphology, FT-IR, mechanical property, and contact angle analyses. Moreover, in vitro cell responses were observed according to the various concentration ratios of HEMA and MMA. Consequently, various morphologies and pore sizes were observed by changing the HEMA and MMA ratio. The mechanical properties and contact angle of the fabricated scaffolds were measured according to the HEMA and MMA concentration ratio. The results were as follows: compressive maximum stress: 254.24–932.42 KPa; tensile maximum stress: 4.37–30.64 KPa; compressive modulus: 16.14–38.80 KPa; tensile modulus: 0.5–2 KPa; and contact angle: 36.89–74.74°. In terms of the in vitro cell response, the suitable cell adhesion and proliferation of human dermal fibroblast (HDF) cells were observed in the whole scaffold. Therefore, a synthetic hydrogel scaffold with enhanced mechanical properties and suitable fibroblast cell responses could be easily fabricated for use with soft tissue using a specific HEMA and MMA concentration ratio. Full article

This study describes the physicochemical characterisation of interpenetrating hydrogel networks (IHNs) composed of either poly(hydroxyethylmethacrylate, p(HEMA)) or poly(methacrylic acid, p(MAA)), and Pluronic block copolymers (grades F127, P123 and L121). IHNs were prepared by mixing the acrylate monomer with Pluronic block copolymers followed by free radical polymerisation. p(HEMA)–Pluronic blends were immiscible, evident from a lack of interaction between the two components (Raman spectroscopy) and the presence of the glass transitions (differential scanning calorimetry, DSC) of the two components. Conversely, IHNs of p(MAA) and each Pluronic were miscible, displaying a single glass transition and secondary bonding between the carbonyl group of p(MAA) and the ether groups in the Pluronic block copolymers (Raman and ATR-FTIR spectroscopy). The effect of storage of the IHNs in Tris buffer on the physical state of each Pluronic and on the loss of Pluronic from the IHNs were studied using DSC and gravimetric analysis, respectively. Pluronic loss from the IHNs was dependent on the grade of Pluronic, time of immersion in Tris buffer, and the nature of the IHN (p(HEMA) or p(MAA)). At equilibrium, the loss was greater from p(HEMA) than from p(MAA) IHNs, whereas increasing ratio of poly(propylene oxide) to poly(ethylene oxide) decreased Pluronic loss. The retention of each Pluronic grade was shown to be primarily due to its micellization; however, hydrogen bonding between Pluronic and p(MAA) (but not p(HEMA)) IHNs contributed to their retention. Full article

In this study, poly(HEMA-PEGxMEM-IA) hydrogels were prepared by radical copolymerization of poly(ethylene glycol) methyl ether methacrylate (PEGxMEM), 2-hydroxyethyl methacrylate (HEMA), and itaconic acid (IA). The reaction was carried out in ethanolic solution using N,N′-methylenebisacrylamide (MBA) as a crosslinking agent and 1-hydroxycyclohexyl phenyl ketone (HCPK) as a photo-initiator. The poly(HEMA-PEGxMEM-IA) hydrogels (HGx) were evaluated as a delivery system for ursolic acid (UA), a phytochemical extracted from the plant Clinopodium revolutum, “flor de arena”. The hydrogels were characterized by Fourier-transform infrared spectroscopy (FTIR-ATR), Raman spectroscopy, X-Ray diffraction (XRD), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The swelling behavior was studied in buffer solutions from pH 2 to 10, specifically at pH 2.2 (gastric environment) and 7.4 (intestinal environment). It was found that the hydrogels studied showed sensitivity to pH. At pH 2.2, the degree of swelling for HG₅ and HG₉ hydrogels was 0.45 and 0.93 (g water/g hydrogel), respectively. At pH 7.4, the degree of swelling for HG₅ and HG₉ hydrogels was 1.97 and 2.64 (g water/g hydrogel), respectively. The SEM images show the variation in pore size as a function of pH, and the UA crystals in the pores of the hydrogels can also be observed. The in vitro UA release data best fit the Korsmeyer–Peppas kinetic model and the diffusion exponent indicates that the release mechanism is governed by Fickian diffusion. Full article

Microneedle arrays are minimally invasive devices that have been extensively investigated for the transdermal/intradermal delivery of drugs/bioactives. Here, we demonstrate the release of bioactive molecules (estradiol, melatonin and meropenem) from poly(2-hydroxyethyl methacrylate), pHEMA, hydrogel-based microneedle patches in vitro. The pHEMA hydrogel microneedles had mechanical properties that were sufficiently robust to penetrate soft tissues (exemplified here by phantom tissues). The bioactive release from the pHEMA hydrogel-based microneedles was fitted to various models (e.g., zero order, first order, second order). Such pHEMA microneedles have potential application in the transdermal delivery of bioactives (exemplified here by estradiol, melatonin and meropenem) for the treatment of various conditions. Full article

Unfractionated heparin (UFH) and its low-molecular-weight fragments (LMWH) are widely used as anticoagulants for surgical procedures and extracorporeal blood purification therapies such as cardiovascular surgery and dialysis. The anticoagulant effect of heparin is essential for the optimal execution of extracorporeal blood circulation. However, at the end of these procedures, to avoid the risk of bleeding, it is necessary to neutralize it. Currently, the only antidote for heparin neutralization is protamine sulphate, a highly basic protein which constitutes a further source of serious side events and is ineffective in neutralizing LMWH. Furthermore, dialysis patients, due to the routine administration of heparin, often experience serious adverse effects, among which HIT (heparin-induced thrombocytopenia) is one of the most severe. For this reason, the finding of new heparin antagonists or alternative methods for heparin removal from blood is of great interest. Here, we describe the synthesis and characterization of a set of biocompatible macroporous cryogels based on poly(2-hydroxyethyl methacrylate) (pHEMA) and L-lysine with strong filtering capability and remarkable neutralization performance with regard to UFH and LMWH. These properties could enable the design and creation of a filtering device to rapidly reverse heparin, protecting patients from the harmful consequences of the anticoagulant. Full article

This work concerns the verification of the self-healing ability of PP-co-HUPy copolymers dispersed in epoxy systems. PP is the acronym for the Poly-PEGMA polymer, and HUPy refers to the HEMA-UPy copolymers based on ureidopyrimidinone (UPy) moieties. In particular, this work aims to verify whether this elastomer characterized by an intrinsic self-healing ability can activate supramolecular interactions among polymer chains of an epoxy resin, as in the elastomer alone. The elastomer includes a class of polyethylene glycol monomethyl ether methacrylate-based copolymers, with different percentages of urea-N-2-amino-4-hydroxy-6-methyl pyrimidine-N’-(hexamethylene-n-carboxyethyl methacrylate) (HEMA-UPy) co-monomers. The self-healing capability of these copolymers based on possible quadruple hydrogen bond interactions between polymer chains has been verified. The formulated epoxy samples did not show self-healing efficiency. This can be attributed to the formation of phase segregation that originates during the curing process of the samples, although the PP-co-HUPy copolymers are completely soluble in the liquid epoxy matrix EP. The morphological investigation highlighted the presence of crystals of PP-co-HUPy copolymers, which are in greater quantity in the sample containing the highest weight percentage (7.8 wt%) of HUPy units. Furthermore, the crystals act as promotors for increasing the curing degree (DC) of the epoxy systems containing HUPy units. DC goes from 91.6% for EP to 96.1% and 95.4% for the samples containing weight percentages of 2.5 and 7.8 wt% of HUPy units, respectively. Dynamic mechanical analysis (DMA) shows storage modulus values for epoxy systems containing PP-co-HUPy units lower than that of the unfilled resin EP. The values of maximum in Tan δ (Tg), representing the temperature at which the glass transition occurs, are 220 for the unfilled resin EP, 228 for the sample containing 2.5 wt% of HEMA-UPy units, and 211 for the sample containing 7.8 wt% of HEMA-UPy units. Full article

Poly(2-hydroxyethylmethacrylate-co-2-(dimethylamino)ethyl methacrylate), P(HEMA-co-DMAEMAx), copolymers were quaternized through the reaction of a part of (dimethylamino)ethyl moieties of DMAEMA units with 1-bromohexadecane. Antimicrobial coatings were further prepared through the cross-linking reaction between the remaining DMAEMA units of these copolymers and the epoxide ring of poly(N,N-dimethylacrylamide-co-glycidyl methacrylate), P(DMAm-co-GMAx), copolymers. The combination of P(HEMA-co-DMAEMAx)/P(DMAm-co-GMAx) copolymers not only enabled control over quaternization and cross-linking for coating stabilization but also allowed the optimization of the processing routes towards a more facile cost-effective methodology and the use of environmentally friendly solvents like ethanol. Careful consideration was given to achieve the right content of quaternized units, qDMAEMA, to ensure antimicrobial efficacy through an appropriate amphiphilic balance and sufficient free DMAEMA groups to react with GMA for coating stabilization. Optimal synthesis conditions were achieved by membranes consisting of cross-linked P(HEMA78-co-DMAEMA9-co-qDMAEMA13)/P(DMAm-co-GMA42) membranes. The obtained membranes were multifunctional as they were self-standing and antimicrobial, while they demonstrated a distinct fast response to changes in humidity levels, widening the opportunities for the construction of “smart” antimicrobial actuators, such as non-contact antimicrobial switches. Full article

PD1/PD-L1 antibody therapy is used in the clinic (atezolizumab, avelumab, durvalumab), but its effect is ambiguous, both in patients and in mouse models. The purpose of this work was to analyze the binding of commercial and laboratory-obtained monoclonal antibodies to PD-L1. Previously, we obtained monoclonal antibodies (clone B12) to the extracellular fragment of murine PD-L1 expressed in E. Coli (exPD-L1). The primary screening of monoclonal antibodies by flow cytometry showed a low B12 binding compared to commercial antibodies. Cytokine-stimulated 3D cultures, permeabilized cells, and Western blotting were used to elucidate the causes of low binding on living cells. The permeabilization of cells B16/F10 (mouse melanoma), EL-4 (mouse lymphoma), and COLO357 (human pancreatic cancer) showed the binding of both mouse and human B12 PD-L1 antibodies. With the help of Western blotting, these data were confirmed. However, commercial antibodies (BioLegend, clone 10F.9G2) in this method did not bind to the mouse recombinant exPD-L1 protein, but bound to cell lysates. Cell cultivation on an anti-adhesive polyHEMA substrate led to the binding of B12 antibodies to the surface of cells under 3D cultivation conditions. The stimulation of EL-4 and B16/F10 cells in 3D cultures and subsequent incubation with Cy3-labeled B12 antibodies led to the appearance of pronounced fluorescence in the perinuclear region of cells. Thus, the obtained monoclonal antibodies to mouse exPD-L1 are cross-reactive with human PD-L1 protein; PD-L1 protein translocates to the cell membrane when cultured under 3D conditions into the nucleus and, when stimulated by cytokines, its biosynthesis is activated. The difference in the binding of antibodies B12 and 10F.9G2 may indicate a difference in the conformation of PD-L1 translocated to the membrane. The traffic of intracellular PD-L1 into the nucleus upon activation may indicate the launch of de novo protein synthesis with an altered conformation. Full article