Search Results (195)

Developing multifunctional wound dressings with excellent mechanical properties, strong tissue adhesion, and efficient antibacterial activity is crucial for promoting wound healing. This study prepared a novel nanocomposite hydrogel dressing based on sodium alginate-polyacrylic acid dual crosslinking networks, incorporating tannic acid-coated cellulose nanocrystals (TA@CNC) and in-situ reduced silver nanoparticles for multifunctional enhancement. The rigid CNC framework significantly improved mechanical properties (elastic modulus of 146 kPa at 1 wt%), while TA catechol groups provided excellent adhesion (36.4 kPa to pigskin, 122% improvement over pure system) through dynamic hydrogen bonding and coordination interactions. TA served as a green reducing agent for uniform AgNPs loading, with CNC negative charges preventing particle aggregation. Antibacterial studies revealed synergistic effects between TA-induced membrane disruption and Ag⁺-triggered reactive oxygen species generation, achieving >99.5% inhibition against Staphylococcus aureus and Escherichia coli. The TA@CNC-regulated porous structure balanced swelling performance and water vapor transmission, facilitating wound exudate management and moist healing. This composite hydrogel successfully integrates mechanical toughness, tissue adhesion, antibacterial activity, and biocompatibility, providing a novel strategy for advanced wound dressing development. Full article

To enhance interaction with the host tissue and protect the metal surface, various surface treatments can be applied to dental implants. This study aimed to produce layer-by-layer (LbL) films by alternated immersion of the titanium sample into polyacrylic acid (PAA) and chitosan solutions, obtaining a PAA/chitosan bilayer architecture, seeking to improve the corrosion resistance. For this purpose, 03 experimental groups (n = 05) were performed: Ti-Cp (as control), Ti-Cp+8 bilayers PAA/chitosan, and Ti-Cp+12 bilayers PAA/chitosan. The corrosion behavior was assessed by using open-circuit potential (OCP), potentiodynamic polarization curves (PPcs) and electrochemical impedance spectroscopy (EIS) techniques, conducted in 0.9 wt% NaCl solution at a controlled temperature of 25 ± 1 °C. The samples were characterized morphologically and structurally by atomic force microscope (AFM), scanning electron microscopy/energy-dispersive X-ray (SEM/EDX), and X-ray diffraction (XRD) techniques before and after the corrosion tests. The electrochemical results significantly highlight the beneficial influence of coatings based on PAA/chitosan in enhancing the corrosion resistance of titanium. These findings not only corroborate the feasibility of using alternative materials for the protection of titanium but also open new possibilities for the development of innovative coatings that can be applied within the biomedical sector, serving as mediators for medicinal purposes, particularly in osteoconductive interventions. Full article

Background: Nanomedicine approaches for cancer therapy face significant challenges, including a poor tumor accumulation, limited therapeutic efficacy, and systemic toxicity. We hypothesized that controlling the clustering of poly(acrylic acid-co-maleic acid) (PAM)-coated superparamagnetic iron oxide nanoparticles (SPIONs) would enhance their magnetic properties for improved targeting, while enabling a pH-responsive drug release in tumor microenvironments. Methods: PAM-stabilized SPION clusters were synthesized via arrested precipitation, characterized for physicochemical and magnetic properties, and evaluated for doxorubicin loading and pH-dependent release. A dual targeting approach combining antibody conjugation with magnetic guidance was assessed in cellular models, including a novel alternating magnetic field (AMF) pre-treatment protocol. Results: PAM-SPION clusters demonstrated controlled size distributions (60–100 nm), excellent colloidal stability, and enhanced magnetic properties, particularly for larger crystallites (13 nm). The formulations exhibited a pH-responsive drug release (8.5% at pH 7.4 vs. 14.3% at pH 6.5) and a significant enhancement of AMF-triggered release (17.5%). The dual targeting approach achieved an 8-fold increased cellular uptake compared to non-targeted formulations. Most notably, the novel AMF pre-treatment protocol demonstrated an 87% improved therapeutic efficacy compared to conventional post-treatment applications. Conclusions: The integration of targeting antibodies, magnetic guidance, and a pH-responsive PAM coating creates a versatile theranostic platform with significantly enhanced drug delivery capabilities. The unexpected synergistic effect of the AMF pre-treatment represents a promising new approach for improving the therapeutic efficacy of nanoparticle-based cancer treatments. Full article

The development of antibacterial coatings for biomedical applications is crucial to prevent implant-associated infections (IAIs). In this study, we designed and evaluated a multilayer coating based on chitosan (CHI), polyacrylic acid (PAA), and triclosan (TCS) using the layer-by-layer (LbL) self-assembly technique. The successful incorporation of TCS was confirmed by Fourier-transform infrared (FTIR) spectroscopy. Surface roughness and topography were analyzed using atomic force microscopy (AFM) and scanning electron microscopy (SEM). Additionally, the pH-dependent behavior of PAA/CHI films was studied to assess its effect on TCS loading. According to disk diffusion assays, coatings assembled at pH 5 (PAA5/CHI5/TCS) exhibited the strongest antibacterial activity, with inhibition zones of 60.0 ± 0.0 mm for S. aureus and 33.67 ± 1.5 mm for E. coli. The long-term stability of the coatings was evaluated by measuring the antibacterial activity after 1, 10, 20, 30, and 40 days, with results confirming that antimicrobial properties and structural integrity were preserved over time. Furthermore, TCS release kinetics were assessed under physiological (pH 7.4) and acidic (pH 5.5) conditions, revealing enhanced release at pH 5.5. These findings highlight the potential of this multilayer system for biomedical applications requiring both stability and pH-responsive drug release. Full article

Rare-earth nanoparticles (RE-NPs), particularly NaYF₄:Yb³⁺,Er³⁺, have emerged as a promising class of photoluminescent probes for bioimaging and sensing applications. These nanomaterials are characterized by their ability to absorb low-energy photons and emit higher-energy photons through an upconversion luminescence process. This process can be triggered by continuous-wave (CW) light excitation, providing a unique optical feature that is not exhibited by native biomolecules. However, the application of upconversion nanoparticles (UCNPs) in bioimaging requires systematic optimization to maximize the signal and ensure biological compatibility. In this work, we synthesized hexagonal-phase UCNPs (average diameter: 29 ± 3 nm) coated with polyacrylic acid (PAA) and established the optimal conditions for imaging human erythrocytes. The best results were obtained after a 4-h incubation in 100 mM HEPES buffer, using a nanoparticle concentration of 0.01 mg/mL and a laser current intensity of 250–300 mA. Under these conditions, the UCNPs exhibited minimal cytotoxicity and were found to predominantly localize at the erythrocyte membrane periphery, indicating surface adsorption rather than internalization. Additionally, a machine learning model (Random Forest) was implemented that classified the photoluminescent signal with 80% accuracy and 83% precision, with the signal intensity identified as the most relevant feature. This study establishes a quantitative and validated protocol that balances signal strength with cell integrity, enabling robust and automated image analysis. Full article

Functional fabrics embedded with active materials that can be released in a controlled manner upon external triggering have been explored for biomedical and cosmetic applications. This study introduces a method for the fabrication of nonwoven fabrics coated with crosslinked polyvinyl alcohol (PVA) for in situ encapsulation and controlled release of hydrophilic active agent, allantoin. Two types of crosslinked coatings were examined using citric acid (CA) or polyacrylic acid (PAA) as crosslinkers. Based on gel content, differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) analyses PVA:CA coatings exhibited a higher crosslinking density compared to PVA:PAA systems. Swelling behavior was measured at 62% after 30 min for PVA:PAA 7:3 films and 36% after 60 min for PVA:CA 7:3 crosslinked films. The release of allantoin from the coated fabrics was influenced by the coating thickness (250–330 µm), the formulation viscosity (8–250 cP), allantoin content (1.2–4.2 mg) and the molecular weight between crosslinks (M_C) 1,000,000–494 g/mol. PVA:CA 7:3 coating allowed the controlled release of 97% allantoin over 8 h, whereas PVA:PAA 7:3 coating exhibited a more prolonged release profile, with 96% of allantoin released over 20 h. Kinetic analyses of the release profiles revealed a good agreement with zero-order release. Full article

Per- and polyfluoroalkyl substances (PFASs), used since the 1940s, are persistent and carcinogenic pollutants. Water is a major exposure route; effective removal is essential. While nanofiltration (NF) and reverse osmosis (RO) are effective but costly, ultrafiltration (UF) membranes offer advantages such as lower cost and higher flux, but their relatively large pore size makes them ineffective for PFAS compounds like perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA). Since PFAS removal depends on both pore size and surface properties, this study investigates the effect of polyelectrolyte multilayer coatings using poly(allylamine hydrochloride) (PAH) and poly(acrylic acid) (PAA) on the zeta potential of UF membranes. Pristine UF membranes showed limited performance (UP150: ~2% for both PFOS and PFOA; UP020: 34.4% PFOS, 24.1% PFOA), while coating significantly enhanced removal (coated UP150: 45.3% PFOS, 43.4% PFOA; coated UP020: 77.8% PFOS, 73.3% PFOA). The modified UF membranes achieved PFAS removal efficiencies significantly closer to NF membranes, though still below those of RO (e.g., BW30XLE: up to 91.0% PFOS, 88.3% PFOA; NP030: up to 81.0% PFOS, 79.3% PFOA). Findings emphasize the importance of membrane surface charge and suggest that modified UF membranes offer a promising, low-cost alternative for PFAS removal under low-pressure conditions. Full article

This study examines the surface-dependent formation of interpolymer complexes (IPCs) by the layer-by-layer (LBL) deposition method. The materials used in this analysis are poly(acrylic acid) (PAA) combined with cellulose ethers, namely methyl cellulose (MC), hydroxypropyl cellulose (HPC), and hydroxyethyl cellulose (HEC), and poloxamers PX188 and PX407. PMMA, PS, and glass surfaces have been used to study the influence of hydrophobicity and hydrophilicity on IPC growth and its properties. Through contact angle measurements, PMMA and PS were found to be hydrophobic and glass hydrophilic. It was revealed by gravimetric analysis that IPC films reveal the highest growth on PMMA substrates, followed by PS and glass. Both the molecular weight of HEC and the hydrophobicity of the surface considerably affected the growth. Hydrogen-bonded complexation was evident by means of FTIR spectroscopy, while changes in some characteristic absorption bands demonstrated the extent of interactions between polymers. Scanning electron microscopy showed that variations in the microstructure of surfaces occur; PAA-MC and poloxamer complex layers were well organized on hydrophobic substrates. Thus, the experimental results showed surface properties, especially hydrophobicity, to be important for IPC growth and structure. These findings contribute to the understanding of IPC behavior on different substrates, thus giving insights into applications in drug delivery, coatings, and functional films. Full article

A solid phase microextraction (SPME) method coupled with liquid chromatography (LC) and fluorescence/ultraviolet-diode array detection was developed for the simultaneous determination of quercetin and trans-resveratrol. The chromatographic, detection, and SPME extraction/desorption conditions were systematically optimized. The performance of four commercial SPME fibers—polyacrylate (PA), polyethylene glycol (PEG), polydimethylsiloxane (PDMS), and polydimethylsiloxane-divinylbenzene (PDMS-DVB)—was evaluated and compared with a homemade polydopamine (PDA)-coated fiber. While all of the fibers successfully extracted the target analytes, their efficiencies varied significantly. The PA, PEG, and PDA fibers demonstrated superior performance, exhibiting wide linearity ranges (0.03–1 µg/mL (PA and PEG) and 0.06–1 µg/mL (PDA) for quercetin, 0.01–1 µg/mL for trans-resveratrol); high sensitivity (LODs of 0.01 µg/mL (PA and PEG) and 0.02 µg/mL (PDA) for quercetin, 0.003 µg/mL for trans-resveratrol); and excellent precision. Among these, the polyacrylate coating delivered the best analytical performance and was selected for further application. The optimized method was applied to analyze winemaking by-products (seeds, skins, and stalks) using SPME on ethanol-macerated extracts subjected to brief ultrasonication. Quercetin and trans-resveratrol were quantified in pomace extracts at concentrations of 104.3 ± 8.2 µg/g and 38.5 ± 4.1 µg/g, respectively. Recovery experiments confirmed the method’s accuracy, with recoveries of 99.1 ± 7.4% for quercetin and 98.5 ± 9.8% for trans-resveratrol. This study establishes a reliable, sensitive, and efficient approach for the determination of these bioactive compounds in complex matrices, with potential applications in the food and pharmaceutical industries. Full article

In this study, polymer films based on the inorganic sorbents Al₂O₃, ZrO₂ and SiO₂-phenyl with repellent N,N-diethyl-3-methylbenzamide were prepared and used as functional textile coatings. The high sorption activity of oxides with respect to N,N-diethyl-3-methylbenzamide (63–239 mg/g) allows for the use of these compounds as repellent carrier materials, and their mixture with polyacrylates allows for the formation of functional coatings–polymer films. Scanning electron microscopy and Fourier transform infrared spectroscopy results revealed that the inorganic sorbents Al₂O₃, ZrO₂ and SiO₂-phenyl were successfully anchored in the polyacrylate structure, and the FTIR spectra confirmed the presence of repellent molecules. The thermal diffusion parameters of N,N-diethyl-3-methylbenzamide were also calculated via thermogravimetric analysis and high-performance liquid chromatography with diode array detection. The highest thermal diffusion rates and concentrations were observed for the material with Al₂O₃ (up to 148.3∙10⁻⁹ mol at 200 °C), and lower values for ZrO₂ and SiO₂-phenyl (up to 15.2∙10⁻⁹ mol and 34.3∙10⁻⁹ mol at 200 °C, respectively). The heat flux parameter J_f was also calculated according to Onsager’s theory and Fourier’s law. The release of repellent from polymeric materials can be achieved by applying less heat than that required to reach the boiling point of N,N-diethyl-3-methylbenzamide. Full article

Water pollution is a major environmental issue caused by the discharge of untreated or partially treated wastewater into rivers and oceans. Self-healing materials, which can repair localized damage, have become a promising approach to counter membrane performance decline from mechanical wear. However, ensuring stability and effectiveness in self-healing membranes remains a challenge. Polyvinyl alcohol (PVA) has been widely studied for its self-healing properties, while polyacrylic acid (PAA) is often used as a crosslinking agent due to its compatibility with PVA, especially in biomedical and filtration applications. In this study, a self-healing PVA-PAA coating was applied to a PES membrane. The PVA solution (5 wt%) was prepared by dissolving beads in distilled water and stirring at 80 °C for 6 h, while the PAA solution was diluted to match this concentration. The two solutions were mixed in a 3:1 molar ratio and heated to form a homogenous mixture, then coated onto PES membranes and crosslinked at 140 °C. Scanning electron microscopy (SEM) revealed a uniform, crack-free coating on the membrane surface. The mechanical properties of the membrane show a tensile strength of 4.85 MPa and elongation of 71.9%. Filtration tests showed that the PVA-PAA-coated PES membrane achieved a water flux of 36.16 L/m²h. The performance of the PVA-PAA coated PES membrane remained stable in terms of water flux and dye rejection after it healed, and the water flux was recorded at the range of 34.24 to 36.02 L/m²h after the seal healing. This self-healing PVA-PAA coated PES membrane demonstrates the practical potential for sustainable water treatment, offering reduced maintenance and extended lifespan for filtration systems. Full article

Proton beam therapy (PBT) is a rapidly advancing modality of hadron therapy. The primary advantage of proton therapy lies in a unique depth-dose distribution characterized by the Bragg peak, which enables a highly targeted irradiation of the area limited to the tumor, while minimizing the impact on healthy tissues. However, a broader clinical adoption of the ion beam therapy is limited by both economic and radiobiological constraints. One of the possible ways to increase the relative biological effectiveness (RBE) of proton therapy involves the use of radiosensitizers. Background/Objectives: In this work, we investigated the efficacy of using colloidal solutions of lanthanum hexaboride (LaB₆) nanoparticles (NPs) coated with polyacrylic acid (PAA) as sensitizers to increase the antitumor biological effectiveness of proton irradiation. This material has not yet been studied extensively so far, despite its promising physical and chemical properties and several reports on its biocompatibility. Methods: LaB₆ NPs were synthesized by femtosecond pulsed laser ablation, functionalized with PAA and characterized. The safety of NPs was evaluated in vitro using a Live/Dead assay on cell cultures: EMT6/P, BT-474, and in vivo in Balb/c mice after intravenous (i.v.) administration. The efficacy of binary proton therapy was evaluated in vitro on cell cultures: EMT6/P, BT-474, and in vivo in the model of human ductal carcinoma of the mammary gland BT-474 in female Nu/j mice after intratumoral (i.t.) administration at a dose of 2.0 mg/mouse and local proton irradiation (fractional exposure of 31 Gy + 15 Gy). The biodistribution of LaB₆-PAA NPs in the animal body was also evaluated. Results: Significant enhancement in cancer cell death following proton beam irradiation was demonstrated in vitro on EMT6/P, BT-474 cell lines. Although the antitumor efficacy observed in vivo was comparatively lower—likely due to the high sensitivity of the BT-474 xenografts—both proton monotherapy and binary treatment were well tolerated. Conclusions: LaB₆-PAA NPs show promise as efficient sensitizers capable of enhancing the biological efficacy of proton therapy, offering a potential path forward for improving therapeutic outcomes. Full article

Waterborne polymer coated controlled release fertilizers (CRFs) are highly valued for their potential to enhance nitrogen use efficiency (NUE) and reduce fertilization labor costs. However, their application in crops with long growth periods, such as rice and maize, is limited by inadequate coating strength and suboptimal hydrophobicity. Inspired by the hydrophobic and anti-fouling structure of lotus leaf cuticles, this study biomimetically modified waterborne polyacrylate-coated urea (PACU) using natural bio-wax including rice bran wax (RBW), candelilla wax (CAW), bees wax (BW) and carnauba wax (CW), along with paraffin wax (PW) as a control. The modifications significantly extended nutrient release duration by 22 d compared to unmodified PACU, with CW providing the longest duration, followed by CAW, BW, RBW, and PW. Additionally, the modification of BW, CAW, and CW exhibited superior hydrophobicity and affinity to polyacrylate coatings, while the inferior hardness and toughness of PW compromised its controlled release performance. Field trials demonstrated that CW-modified CRFs effectively controlled nutrient release in rice and maize, resulting in a 7.2% increase in rice yield and a 37.9% increase in maize yield, as well as an 18.7% improvement in NUE compared to conventional fertilizers. These findings offered a novel approach for hydrophobic modification of waterborne polymer coatings, thereby enhancing the performance and applicability of waterborne polymer coated CRFs in long-season crops. Full article

The emergence of methicillin-resistant Staphylococcus aureus (MRSA) is still posing a global challenge in healthcare settings. This bacterial strain is a cause of severe periprosthetic infection, thereby impairing the success of implant insertion. To address this issue, implant surface modification is required. Herein, we developed a novel multilayered silver nanoparticle/polyacrylic acid-coated Ti plate (AgNPs/PAA/Ti) using an in-house dip coater. AgNPs were synthesized and characterized. The dip-coating process was optimized based on the dipping rate, evaporation time, and coating cycle number. Uniform and reproducible coatings were achieved on Ti surfaces, with consistency verified through SEM analysis. The average size of the AgNPs was approximately 36.50 ± 0.80 nm with a PDI of 0.443 ± 0.025, and the zeta potential was measured at around –23.3 ± 2.0 mV. The maximum coating thickness of 83.5 ± 1.3 µm was observed at 15 cycles of dip coating. Moreover, our developed AgNPs/PAA/Ti plate showed both antimicrobial and biofilm-resistant performance, while also exhibiting enhanced biocompatibility with cultured MG63 osteosarcoma cells, maintaining cell viability greater than 70%. We envisage that this material holds significant promise as a candidate for medical implant devices, offering protection against MRSA-associated infection at insertion sites with low vascularity in the future. Full article

Progressive climate change increases drought frequency, severely impacting crop growth and yield. New eco-friendly alternatives to chemical protection agents and fertilisers are needed to reduce pollution and enhance plant health. This study evaluated the effects of the plant growth-promoting rhizobacteria (PGPR) and the hydrogel (potassium polyacrylate) on Brassica napus L. during drought conditions. After in vitro and pot experiments, Serratia plymuthica was selected from six PGPR candidates based on its ability to enhance plant biomass, shoot length, and number of internodes. The seed viability test, reactive oxygen species accumulation, and SOD activity showed no adverse effects of applying hydrogel to canola seeds. Moreover, the hydrogel did not show toxicity towards tested bacterial strains. Field trials during the drought demonstrated that inoculation with S. plymuthica significantly increased the number of siliques (16.48%) and yield (19.93%), compared to controls. Plants grown from inoculated seeds were also taller (3.28%) and had more branches (39.99%). We also analysed seedling emergence, number of internodes, thousand seeds’ weight, and seed moisture. The hydrogel applied to the soil delayed seedling emergence and dampened the growth-promoting effect of S. plymuthica, resulting in reduced yield. Compared with plants inoculated with S. plymuthica, there was a decrease in the yield of plants treated solely with hydrogel and in plants treated with hydrogel and the bacterium of 23.61% and 27.79%, respectively. Our results indicate that S. plymuthica has a high potential for use in commercial canola farming, especially as an ingredient added to seed coatings. Full article