Search Results (674)

Titanium is widely recognized as an interesting material for electrodes due to its excellent corrosion resistance, mechanical strength, and biocompatibility. However, further functionalization is often necessary to impart advanced interfacial properties, such as selective ion transport or stimuli responsiveness. In this context, the integration of smart polymers, such as poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA)—noted for its dual pH- and thermo-responsive behavior—has emerged as a promising approach to tailor surface properties for next-generation devices. This work compares two covalent immobilization strategies for PDMAEMA on titanium: the “graft-to” method, involving the attachment of pre-synthesized polymer chains, and the “graft-from” method, based on surface-initiated polymerization. The resulting materials were characterized with size exclusion chromatography (SEC) for molecular weight, Fourier-transform infrared spectroscopy (FTIR) for chemical structure, scanning electron microscopy (SEM) for surface morphology, and contact angle measurements for wettability. Electrochemical impedance spectroscopy and polarization studies were used to assess electrochemical performance. Both strategies yielded uniform and stable coatings, with the mode of grafting influencing both surface morphology and functional stability. These findings provide valuable insights into the development of adaptive, stimuli-responsive titanium-based interfaces in advanced electrochemical systems. Full article

Periodontitis, a chronic inflammatory disease, causes alveolar bone loss. Current treatments show limitations in achieving dual antimicrobial and anti-inflammatory effects. We evaluated an emodin-loaded thermoresponsive hydrogel as a local drug delivery system for periodontitis treatment. Emodin itself demonstrated antibacterial activity against Porphyromonas gingivalis, with minimal inhibitory and minimal bactericidal concentrations of 50 μM. It also suppressed mRNA expression of proinflammatory cytokines [tumor necrosis factor alpha, interleukin (IL)-1β, and IL-6] in lipopolysaccharide-stimulated RAW 264.7 cells. The hydrogel, formulated with poloxamers and carboxymethylcellulose, remained in a liquid state at room temperature and formed a gel at 34 °C, providing sustained drug release for 96 h and demonstrating biocompatibility with human periodontal ligament stem cells while exhibiting antibacterial activity against P. gingivalis. In a rat model of periodontitis, the hydrogel significantly reduced alveolar bone loss and inflammatory responses, as confirmed by micro-computed tomography and reverse transcription quantitative polymerase chain reaction of gingival tissue. The dual antimicrobial and anti-inflammatory properties of emodin, combined with its thermoresponsive delivery system, provide advantages over conventional treatments by maintaining therapeutic concentrations in the periodontal pocket while minimizing systemic exposure. This shows the potential of emodin-loaded thermoresponsive hydrogels as effective local delivery systems for periodontitis treatment. Full article

Firstly, this paper reviews the fundamental theories of solid surface wettability and contact angle hysteresis. Subsequently, it further introduces four typical wettability-engineered surfaces with low hysteresis (superhydrophobic, superamphiphobic, super-slippery, and liquid-like smooth surfaces). Finally, it focuses on the latest research progress in the field of droplet manipulation on open planar surfaces with engineered wettability. To achieve droplet manipulation, the core driving forces primarily stem from natural forces guided by bioinspired gradient surfaces or the regulatory effects of external fields. In terms of bioinspired self-propelled droplet movement, this paper summarizes research inspired by natural organisms such as desert beetles, cacti, self-aligning floating seeds of emergent plants, or water-walking insects, which construct bioinspired special gradient surfaces to induce Laplace pressure differences or wettability gradients on both sides of droplets for droplet manipulation. Moreover, this paper further analyzes the mechanisms, advantages, and limitations of these self-propelled approaches, while summarizing the corresponding driving force sources and their theoretical formulas. For droplet manipulation under external fields, this paper elaborates on various external stimuli including electric fields, thermal fields, optical fields, acoustic fields, and magnetic fields. Among them, electric fields involve actuation mechanisms such as directly applied electrostatic forces and indirectly applied electrocapillary forces; thermal fields influence droplet motion through thermoresponsive wettability gradients and thermocapillary effects; optical fields cover multiple wavelengths including near-infrared, ultraviolet, and visible light; acoustic fields utilize horizontal and vertical acoustic radiation pressure or acoustic wave-induced acoustic streaming for droplet manipulation; the magnetic force acting on droplets may originate from their interior, surface, or external substrates. Based on these different transport principles, this paper comparatively analyzes the unique characteristics of droplet manipulation under the five external fields. Finally, this paper summarizes the current challenges and issues in the research of droplet manipulation on the open planar surfaces and provides an outlook on future development directions in this field. Full article

Zwitterionic hydrogels have emerged as eco-friendly anti-fouling materials owing to their superior hydration-mediated resistance to biofouling. Nevertheless, their practical utility remains constrained by intrinsically poor mechanical robustness. Herein, this study proposes a novel strategy to develop novel tough zwitterionic hydrogels by freezing the gels’ polymer network. As a proof of concept, a zwitterionic hydrogel was synthesized via copolymerization of hydrophobic monomer phenyl methacrylate (PMA) and hydrophilic cationic monomer N-(3-dimethylaminopropyl) methacrylamide (DMAPMA), followed by post-oxidation to yield a zwitterionic structure. At service temperature, the rigid and hydrophobic PMA segments remain frozen, while the hydrophilic zwitterionic units maintain substantial water content by osmotic pressure. Synergistically, the zwitterionic hydrogel achieves robust toughness and adhesiveness, with high rigidity (66 MPa), strength (4.78 MPa), and toughness (2.53 MJ/m³). Moreover, the hydrogel exhibits a distinct temperature-dependent behavior by manifesting softer and more stretchable behavior after heating, since the thawing of the gel network at high temperatures increases segmental mobility. Therefore, it achieved satisfactory adhesiveness to substrates (80 kPa). Additionally, the hydrogel demonstrated remarkable anti-fouling performance, effectively suppressing biofilm formation and larval attachment. In summary, this work opens up promising prospects for the development of zwitterionic hydrogels with high application potential. Full article

Traditional wound and burn treatments often fall short in balancing antimicrobial efficacy, patient comfort, and ease of application. This study introduces a novel, transparent, thermoresponsive sol–gel formulation incorporating polyhexamethylene biguanide (PHMB) for advanced topical therapy. Utilizing Poloxamer 407 as a biocompatible carrier, the formulation remains a sprayable liquid at room temperature and instantly gels upon contact with body temperature, enabling painless, pressure-free application on sensitive, injured skin. Comprehensive in vitro and in vivo evaluations confirmed the formulation’s broad-spectrum antimicrobial efficacy (≥5 log₁₀ reduction in 30 s), high biocompatibility (viability > 70% in fibroblasts), non-irritancy (OECD 425-compliant), and physical stability across three months. Importantly, the formulation maintained fibroblast migration capacity—crucial for wound regeneration—while exhibiting rapid sol-to-gel transition at ~34 °C. These findings highlight the system’s potential as a next-generation wound dressing with enhanced user compliance, transparent monitoring capability, and rapid healing support, particularly in disaster or emergency scenarios. Full article

In high-slope substrates, special requirements are imposed on sprayed ecological soil, which needs to exhibit high rheological properties before spraying and rapid curing after spraying. Traditional stabilizers are often unable to meet these demands. This study developed a thermo-responsive hydrogel stabilizer (HSZ) and applied it to ecological soil. The effects of HSZ on the rheological, mechanical, and vegetation performance of ecological soil were investigated, and the mechanism of the responsive carrier in the stabilizer was explored. The experimental results show that the ecological soil containing HSZ has high flowability before response, but its flowability rapidly decreases and consistency sharply increases after response. After the addition of HSZ, the 7 d unconfined compressive strength of the ecological soil reaches 1.55 MPa. The pH value of the ecological soil generally ranges from 6.5 to 8.0, and plant growth in a simulated vegetation box is favorable. Conductivity and viscosity tests demonstrate that the core–shell microcarriers, upon thermal response, release crosslinking components from the carrier, which rapidly react with the precursor solution components to form a curing system. This study provides a novel method for regulating ecological soil using a responsive stabilizer, further expanding its capacity to adapt to various complex scenarios. Full article

Osteoarthritis and metastatic bone cancers create pathological oxidative environments characterized by elevated reactive oxygen species (ROS). ROS impair bone regeneration by degrading the scaffold and suppressing mineralization. To address these challenges, we fabricated thermoresponsive scaffolds based on poly(N-isopropylacrylamide) (PNIPAAm) incorporating in situ-grown nanohydroxyapatite on graphene oxide nanoscrolls (nHA-GONS) using stereolithography (SLA). Three scaffold formulations were studied: pure PNIPAAm (PNP), PNIPAAm with 5 wt.% nHA-GONS (P5G), and PNIPAAm with 5 wt.% nHA-GONS reinforced with polycaprolactone (PCL) microspheres (PN5GP). Each scaffold was evaluated for (i) swelling and lower critical solution temperature (LCST) using differential scanning calorimetry (DSC); (ii) oxidative degradation assessed using Fourier-transform infrared spectroscopy (FTIR), mass loss, and antioxidant assays; and (iii) mineralization and morphology via immersion in simulated body fluid followed by microscopy. The PN5GP and P5G scaffolds demonstrated reversible swelling, sustained antioxidant activity, and enhanced calcium deposition, which enable redox stability and mineralization under oxidative environments, critical for scaffold functionality in bone repair. PNP scaffolds exhibited copper accumulation, while PN5GP suffered from accelerated mass loss driven by the PCL phase. These findings identify the P5G formulation as a promising scaffold. This study introduces a quantitative framework that enables the predictive design of oxidation-resilient scaffolds. Full article

The design of emulsions at the nanoscale is a significant application of nanotechnology. For spherical droplets and a given volume of dispersed phase, the nanometre size of droplets inversely increases the total area, $A={\displaystyle \frac{3V}{r}}$, allowing greater contact with organic and inorganic materials during application. In topical applications, not only is cell contact increased, but also permeability in the cell membrane. Nanoemulsions typically achieve kinetic stability rather than thermodynamic stability, so their commercial application requires reasonable resistance to flocculation and coalescence, which can be affected by temperature changes. Therefore, their thermoresponsive characterisation becomes relevant. In this work, we analyse this response in an O/W nanoemulsion of Palmarosa for antibacterial purposes that has already shown stability for one year at controlled room temperature. We now study hysteresis processes and the behaviour of the statistical distribution in droplet size by Dynamic Light Scattering, obtaining remarkable stability under temperature changes up to 50 °C. This includes a maintained chemical composition observed using Fourier Transform Infrared Spectroscopy and the preservation of antibacterial properties analysed through optical density tests on cultures and the Spread-Plate technique for bacteria colony counting. We obtain practically closed hysteresis curves for some tracers of droplet size distributions through controlled thermal cycles between 10 °C and 50 °C, exhibiting a non-linear behaviour in their distribution. In general, the results show notable physical, chemical, and antibacterial stability, suitable for commercial applications. Full article

It is widely recognized that fine surface structures found in nature contribute to surface functionality, and studies on the design of functional materials based on biomimetics have been actively conducted. In this study, polymer thin films with hierarchically ordered surface structure were prepared by combining both nanoimprinting using anodically oxidized porous alumina (AAO) as a template and surface-initiated atom transfer radical polymerization (SI-ATRP). To prepare such polymer films, we designed a new copolymer (poly{[2-(4-methyl-2-oxo-2H-chromen-7-yloxy)ethyl methacrylate]-co-[2-(2-bromo-2-methylpropionyloxy)ethyl methacrylate]}; poly(MCMA-co-HEMABr)) with coumarin moieties and α-haloester moieties in the pendants. The MCMA repeating units function to fix the pillar structure by photodimerization, and the HEMABr ones act as the polymerization initiation sites for SI-ATRP on the pillar surfaces. Surface structures consisting of vertically oriented multiple pillars were fabricated on the spin-coated poly(MCMA-co-HEMABr) thin films by nanoimprinting using an AAO template. Then, the coumarin moieties inside each pillar were crosslinked by UV light irradiation to fix the pillar structure. SEM observation confirmed that the internally crosslinked pillar structures were maintained even when immersed in organic solvents such as 1,2-dichloroethane and anisole, which are employed as solvents under SI-ATRP conditions. Finally, poly(2,2,2-trifluoroethyl methacrylate) and poly(N-isopropylacrylamide) chains were grafted onto the thin film by SI-ATRP, respectively, to prepare the hierarchically ordered surface structure. Furthermore, in this study, the surface properties as well as the thermoresponsive hydrophilic/hydrophobic switching of the obtained polymer films were investigated. The surface morphology and chemistry of the films with and without pillar structures were compared, especially the interfacial properties expressed as wettability. Grafting poly(TFEMA) increased the static contact angle for both flat and pillar films, and the con-tact angle of the pillar film surface increased from 104° for the flat film sample to 112°, suggesting the contribution of the pillar structure. Meanwhile, the pillar film surface grafted with poly(NIPAM) brought about a significant change in wettability when changing the temperature between 22 °C and 38 °C. Full article

Because of their potential “smart” applications, multifunctional stimuli-responsive polymers are gaining increasing scientific interest. The present work explores the possibility of developing such materials based on the hydrolytically stable N-3-dimethylamino propyl methacrylamide), DMAPMA. To this end, the properties in aqueous solution of the homopolymer PDMAPMA and copolymers P(DMAPMA-co-MMA_x) of DMAPMA with the hydrophobic monomer methyl methacrylate, MMA, were explored. Two copolymers were prepared with a molar content x = 20% and 35%, as determined by Proton Nuclear Magnetic Resonance (¹H NMR). Turbidimetry studies revealed that, in contrast to the homopolymer exhibiting a lower critical solution temperature (LCST) behavior only at pH 14 in the absence of salt, the LCST of the copolymers covers a wider pH range (pH > 8.5) and can be tuned within the whole temperature range studied (from room temperature up to ~70 °C) through the use of salt. The copolymers self-assemble in water above a critical aggregation Concentration (CAC), as determined by Nile Red probing, and form nanostructures with a size of ~15 nm (for P(DMAPMA-co-MMA₃₅)), as revealed by transmission electron microscopy (TEM) and dynamic light scattering (DLS). The combination of turbidimetry with ¹H NMR and automatic total organic carbon/total nitrogen (TOC/TN) results revealed the potential of the copolymers as visual CO₂ sensors. Finally, the alkylation of the copolymers with dodecyl groups lead to cationic amphiphilic materials with an order of magnitude lower CAC (as compared to the unmodified precursor), effectively stabilized in water as larger aggregates (~200 nm) over a wide temperature range, due to their increased ζ potential (+15 mV). Such alkylated products show promising biocidal properties against microorganisms such as Escherichia coli and Staphylococcus aureus. Full article

Background/Objectives: Photothermal therapy (PTT) is an emerging minimally invasive strategy in biomedicine that converts near-infrared (NIR) light into localized heat for the targeted inactivation of pathogens and tumor cells. Methods and Results: In this study, we report the synthesis and characterization of thermoresponsive nanogels composed of poly (N-isopropylacrylamide-co-N-isopropylmethylacrylamide) (PNIPAM-co-PNIPMAM) semi-interpenetrated with polypyrrole (PPy), yielding monodisperse particles of 377 nm diameter. Spectroscopic analyses—including ¹H-NMR, FTIR, and UV-Vis—confirmed successful copolymer formation and PPy incorporation, while TEM images revealed uniform spherical morphology. Differential scanning calorimetry established a volumetric phase transition temperature of 38.4 °C, and photothermal assays demonstrated a ΔT ≈ 10 °C upon 10 min of 850 nm NIR irradiation. In vitro antimicrobial activity tests against Pseudomonas aeruginosa (ATCC 15692) showed a dose-time-dependent reduction in bacterial viability, with up to 4 log CFU/mL. Additionally, gentamicin-loaded nanogels achieved 38.7% encapsulation efficiency and exhibited stimulus-responsive drug release exceeding 75% under NIR irradiation. Conclusions: Combined photothermal and antibiotic therapy yielded augmented bacterial killing, underscoring the potential of PPy-interpenetrated nanogels as smart, dual-mode antimicrobials. Full article

In this paper, different poly((ethylene glycol)-(propylene glycol)) methacrylate (P(EGPG)MA) hydrogels were synthesized by gamma-radiation-induced polymerization and crosslinking from a monomer–bisolvent mixture using the following monomers: (ethylene glycol)₆ methacrylate (EG₆MA), ((ethylene glycol)₆-(propylene glycol)₃) methacrylate (EG₆PG₃MA), ((propylene glycol)₆-(ethylene glycol)₃) methacrylate (PG₆EG₃MA), and (propylene glycol)₅ methacrylate (PG₅MA), along with different water/ethanol compositions as the solvent. The monomer–bisolvent mixture was exposed to various radiation doses (5, 10, 15, 25, and 50 kGy). Considerable emphasis was placed on optimizing and tuning the reaction conditions necessary for the fabrication of methacrylic networks with pendant EGPG terminals. A further investigation was conducted on the effects of monomer composition, different preparation conditions, and radiation processing on thermal properties, microstructure, swelling behavior, and volume phase transition. Special attention was dedicated to PPG₆EG₃MA hydrogel, whose volume phase transition temperature is near physiological temperatures. This study identifies an optimal radiation dose and a water/ethanol solvent ratio for the synthesis of the radiation-induced hydrogels. Employing ionizing radiation within the sterilization dose range enables the simultaneous fabrication and sterilization of these hydrogels, offering an efficient production process. The findings provide new insights into the role of bisolvent composition on hydrogel formation and properties, and they present practical guidelines for optimizing hydrogel synthesis across a wide range of applications. Full article

Retinal diseases can result in blindness and visual impairment. They represent a significant medical burden and adversely affect life expectancy. Recently, antibody- and nucleic acid-based pharmaceuticals have increasingly been used to treat retinal diseases, with improvement or cure as the goal; however, these drugs are currently only administered by intravitreal injection. In this study, we present a novel approach to treating retinal diseases using eye drops that contain PnkRNA, a single-stranded RNA nucleic acid. PnkRNA-loaded liposomes were shown to effectively deliver retinal drugs and significantly inhibit retinal thickening in a mouse retinal-vein occlusion model. Cationic modification of the liposome surface enhanced the delivery of nucleic acids and therapeutic efficacy. Moreover, to reduce the frequency of eye-drop administration, liposomes were incorporated into the thermoresponsive gels. This formulation provided sustained retinal delivery and exhibited superior therapeutic efficacy compared with liposomal eye drops. This nucleic acid retinal delivery technology represents a significant advancement in drug-delivery technology, offering a safe and simple treatment for retinal diseases. Full article

Mesoporous silica nanoparticles (MSNs) are gaining popularity in nanomedicine due to their large surface area, variable pore size, great biocompatibility, and chemical adaptability. In recent years, the combination of smart polymeric materials with MSNs has transformed the area of regulated drug administration, particularly under stimuli-responsive settings. Polymer-modified MSNs provide increased stability, longer circulation times, and, most crucially, the capacity to respond to diverse internal (pH, redox potential, enzymes, and temperature) and external (light, magnetic field, and ultrasonic) stimuli. These systems allow for the site-specific, on-demand release of therapeutic molecules, increasing treatment effectiveness while decreasing off-target effects. This review presents a comprehensive analysis of recent advancements in the development and application of polymer-functionalized MSNs for stimuli-triggered drug delivery. Key polymeric modifications, including thermoresponsive, pH-sensitive, redox-responsive, and enzyme-degradable systems, are discussed in terms of their design strategies and therapeutic outcomes. The synergistic use of dual or multiple stimuli-responsive polymers is also highlighted as a promising avenue to enhance precision and control in complex biological environments. Moreover, the integration of targeting ligands and stealth polymers such as PEG further enables selective tumor targeting and immune evasion, broadening the potential clinical applications of these nanocarriers. Recent progress in stimuli-triggered MSNs for combination therapies such as chemo-photothermal and chemo-photodynamic therapy is also covered, emphasizing how polymer modifications enhance responsiveness and therapeutic synergy. Finally, the review discusses current challenges, including scalability, biosafety, and regulatory considerations, and provides perspectives on future directions to bridge the gap between laboratory research and clinical translation. Full article

Advancements in thermoregulating textiles have been propelled by innovations in nanotechnology, composite materials, and smart fiber engineering. This article reviews recent scholarly papers on experimental passive and active thermoregulating textiles to present the latest advancements in these fabrics, their mechanisms of thermoregulation, and their feasibility for use. The review underscores that phase-change materials enhanced with graphene, boron nitride, and carbon nanofibers offer superior thermal conductivity, phase stability, and flexibility, making them ideal for wearable applications. Shape-stabilized phase-change materials and aerogel-infused fibers have shown promising results in outdoor, industrial, and emergency settings due to their durability and high insulation efficiency. Radiative cooling textiles, engineered with hierarchical nanostructures and Janus wettability, demonstrate passive temperature regulation through selective solar reflection and infrared emission, achieving substantial cooling effects without external energy input. Thermo-responsive, shape-memory materials, and moisture-sensitive polymers enable dynamic insulation and actuation. Liquid-cooling garments and thermoelectric hybrids deliver precise temperature control but face challenges in portability and power consumption. While thermoregulating textiles show promise, the main challenges include achieving scalable manufacturing, ensuring material flexibility, and integrating multiple functions without sacrificing comfort. Future research should focus on hybrid systems combining passive and active mechanisms, user-centric wearability studies, and cost-effective fabrication methods. These innovations hold significant potential for applications in extreme environments, athletic wear, military uniforms, and smart clothing, contributing to energy efficiency, health, and comfort in a warming climate. Full article