Hydroxypropyl cellulose (HPC) nanogels with thermoresponsive properties were synthesized through a novel polymerization pathway. This study determined the optimal concentrations of surfactant and reaction temperature by evaluating the solution dispersity across various HPC molecular weights. An inverse relationship was observed between the molecular weight of HPC and the required concentration of the surfactant dodecyltrimethylammonium bromide (DTAB); polymers with higher molecular weights needed less surfactant. Nanogels were formed at double the lower critical solution temperature (LCST) of the polymer, with divinyl sulfone (DVS) employed as a crosslinking agent to establish the polymer network. This novel synthesis method ultimately resulted in nanogels with a low polydispersity index. Dynamic light scattering (DLS) was used to assess the influence of crosslinker concentration on thermoresponsive behavior, revealing a consistent decrease in average size as the crosslinker molarity increased. Additionally, small-angle neutron scattering (SANS) was utilized to investigate how the internal structural changed with the temperature, highlighting marked deviations from the typical fuzzy sphere morphology. This study of the morphology of HPC nanogels as a function of temperature and molecular weight allows us to better understand the distribution of the polymeric network, investigate the phase transition, and determine the effect of molecular weight on the final size of the nanogels.

Abstract:
The detection of biomolecules such as nutrients, disease biomarkers, drugs, and toxins in human biofluids is essential for advancing healthcare and diagnostics. Traditional centralized laboratory assays, like enzyme-linked immunosorbent assays (ELISA), are limited by sample preparation complexity and processing time. To address these challenges, we initially focused on enhancing ELISA sensitivity by incorporating single-atom nanozymes (SANs) as robust catalytic amplifiers. SANs exhibit exceptional stability across a wide pH and temperature range and display superior catalytic activity toward hydrogen peroxide, effectively substituting natural peroxidases.

We developed methods to integrate SANs into ELISA workflows and expanded their application to electrochemical platforms and lateral-flow immunoassays, enabling rapid and sensitive detection of target analytes in various biological matrices. The SAN-based biosensors demonstrated reproducible performance and significant improvements in sensitivity and stability compared to traditional enzyme-based assays.

To further address the growing demand for continuous, on-body health monitoring, we integrated these SAN-based sensing platforms with flexible, wearable energy management modules, creating a self-powered wearable microgrid system. This system ensures continuous and autonomous operation by harvesting biomechanical and environmental energy from the wearer. Additionally, the lightweight and flexible design of the wearable microgrid system provides enhanced comfort and long-term wearability, enabling real-time, high-frequency monitoring of biomarkers directly on the body.

Conclusions:
The SAN-enabled ELSIA demonstrated ten times greater sensitivity compared to a commercial product in detecting one type of Alzheimer's disease. By transitioning from traditional ELISA to SAN-enabled biosensing and integrating with self-powered, flexible wearable systems, our research paves the way for continuous, autonomous biomolecular monitoring, including glucose, lactate, Vitamin C, and levodopa from sweat. This comprehensive approach meets the demands for real-time, user-friendly healthcare monitoring and advanced human–machine interfacing.

Introduction:
Anthocyanins (AntCys) are natural pigments with pH-sensitive chromatic properties and antioxidant activity, making them attractive for stimuli-responsive materials. However, their application is limited by poor stability in neutral and alkaline environments. This study explores the encapsulation of AntCys, extracted from red cabbage, into surface-nanostructured microparticles obtained via Pickering emulsion polymerization to enhance stability and enable environmental responsiveness.

Methods:
The AntCy extract was incorporated into poly(methacrylic acid) microparticles synthesized using a Pickering emulsion stabilized by silica nanoparticles. Encapsulation efficiency was quantified spectrophotometrically. The release behavior of AntCy was studied in water, saline solution, and ethanol–water mixtures, and interpreted using various kinetic models. Morphology and uptake were evaluated by SEM and colorimetric analysis. Color responses to pH and gas vapors were tested for sensing applications.

Results:
The encapsulated AntCys in the microparticles were predominantly stabilized as flavylium cations inside the acidic polymer matrix. This way, the microparticles could preserve the integrity of AntCys towards degradation in high pH solutions yet maintaining its antioxidant ability. The release of AntCys was highly sensitive to external conditions. In saline and ethanol-rich environments, the release kinetics followed a diffusion-based profile, with increased release rates attributed to ionic screening and enhanced solubility. The colorimetric response of AntCy-loaded microparticles enabled the visual detection of acidic and basic vapors. A biocompatible polyvinyl alcohol composite embedded with microparticles was successfully prototyped for gas sensing.

Conclusions:
Pickering emulsion-derived polymeric microparticles provide a robust platform for encapsulation and stabilization of anthocyanins, enabling controlled release and preserving antioxidant activity. Their pH- and solvent-responsive release profiles, combined with visible colorimetric changes, make them suitable for use in intelligent packaging, biosensors, and environmentally responsive coatings.

Electrochemical overall water splitting (OWS) is a critical technology for the sustainable generation of high-purity hydrogen and oxygen using only water and renewable electricity. The development of Earth-abundant, bifunctional electrocatalysts capable of efficiently driving both the HER and the OER within a single system is imperative for the advancement of alkaline water electrolyzer technologies.

In this study, cobalt phosphide (CoP) and cobalt–iron phosphide (CoFeP) were successfully prepared on a copper substrate via an electroless deposition method using sodium hypophosphite (NaH₂PO₂) as the phosphorus source and the reducing agent. The anchoring of platinum (Pt) nanoparticles onto electrolessly deposited materials was achieved through the galvanic displacement technique. The morphology, composition, and crystallographic structure of the catalysts were investigated using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The bifunctional electrocatalytic performance of the materials for OWS was demonstrated in a two-electrode configuration using a 1 M KOH electrolyte.

Among the catalysts, Pt–CoFeP demonstrated superior bifunctional activity with a low cell voltage of 1.58 V at 10 mA cm^-2 for overall water splitting, surpassing the performance of Pt–CoP due to the synergistic interactions between Co, Fe, and Pt. The incorporation of Fe into the system resulted in enhanced electrical conductivity and modulation of the electronic structure. Platinum decoration led to significant improvements in catalytic kinetics, a reduction in overpotentials, and the facilitation of efficient charge transfer at both electrodes. This work presents a scalable strategy for engineering platinum-modified transition metal phosphides as robust, high-performance bifunctional electrocatalysts for alkaline water electrolysis.

Acknowledgments

This research was funded by a grant (No. P-MIP-23-467) from the Research Council of Lithuania.

Introduction:
Soft, mechanically compliant materials capable of converting mechanical energy into electrical output are essential for the next generation of wearable electronics and self-powered sensors. While piezoelectricity is typically associated with crystalline ceramics or ferroelectric polymers, recent efforts have focused on organic mixed ionic–electronic conductors (OMIECs) as functional alternatives. Here, we report a moldable, water-processable PVA/PANi composite exhibiting strain-sensitive electrical response and piezoelectric-like energy conversion, synthesized through a straightforward frozen-gel polymerization method.

Methods:
Poly(vinyl alcohol) and glycerol were dissolved in water to form a hydrogel precursor, followed by in situ polymerization of aniline under frozen conditions. The composite was subjected to mechanical compression and stretching cycles, and its electrical output was evaluated via open-circuit voltage (VOC), short-circuit current (ISC), and power output across various load resistances. The structure was characterized via scanning electron microscopy (SEM), revealing platelet-like nanoparticle PANi domains embedded in the soft matrix.

Results:
The composite exhibited a reproducible piezoelectric-like response under compressive strain, with VOC reaching 0.08 mV/mm and ISC exceeding 8 µA/mm² at ~4.6% strain. Maximum power density of ~7 nW/cm³ was obtained at an optimal load of 1 kΩ. Theoretical Pmax estimates based on VOC × ISC closely matched experimental results. SEM revealed granular and fibrillar self-assembled nanoparticle PANi domains, likely templated by ice grains during polymerization, suggesting an interface-driven morphological control.

Conclusions:
The PVA/PANi composite exhibits mechano-electrical conversion in the absence of conventional piezoelectric phases, enabled by a unique morphology arising from frozen-gel polymerization. Its moldability, conductivity, and scalability highlight its potential for low-cost, flexible energy harvesting and sensing applications.

Conventional biosensors frequently rely on biological enzymes such as glucose oxidase and peroxidase to catalyse specific biochemical reactions. While effective, these enzymes present several critical limitations, including limited operational stability, high production and storage costs, and sensitivity to environmental conditions. These drawbacks significantly hinder their practical application in long-term diagnostics, portable sensing devices, and resource-limited settings.

This project proposes the development of enzyme-free biosensors using silver nanoparticles (AgNPs) as catalytic substitutes. AgNPs exhibit unique and advantageous physicochemical properties, including a large surface area, excellent electrical conductivity, and intrinsic peroxidase-like activity. These features make them ideal nanozyme candidates for next-generation biosensors that are both efficient and stable under diverse conditions.

This study involves the synthesis and characterisation of AgNPs via chemical and environmentally friendly (green) methods, followed by their integration into both electrochemical and colorimetric biosensing platforms. The biosensors are tested for their ability to detect clinically and industrially relevant biomolecules, particularly glucose and hydrogen peroxide.

Key performance metrics such as the biosensors' sensitivity, detection limit, response time, selectivity, and long-term operational stability are systematically evaluated and compared with those of their conventional enzyme-based counterparts. The ultimate goal is to develop a cost-effective, reusable, and robust biosensor suitable for applications in medical diagnostics, food safety analysis, and environmental monitoring.

This work contributes to the growing field of nanozyme technology by offering an innovative, enzyme-free solution to overcome the limitations of traditional biosensors, paving the way for the development of more durable and accessible sensing platforms.

Upconversion nanoparticles (UCNPs) are materials that convert near-infrared photons into visible and/or UV emissions. This phenomenon generates high-energy radiation from the absorption of low-energy photons. The synthesis of UCNPs requires a support matrix composed of oxides (Y₂O₃) or fluorides (NaYF₄), which are essential for their optical properties. These materiales have a wide range of applications in bioimaging, drug delivery and energy storage in solar devices.

For this, UCNPs were synthesized by coprecipitation method. For better control of particle size and to obtain a beta (β) crystalline phase, the particles were subjected to heat treatment at 400 °C for 17 h inside a muffle. Subsequently, nanoparticles were deposited on a tetraethyl orthosilicate (TEOS) film synthesized by sol–gel technique, in a molar ratio of TEOS/H₂O/Ethanol at pH of 2, 3 and 5 in a temperature range of 25 to 80 ºC.

Both materials were characterized by infrared spectroscopy (FT-IR), X-ray diffraction (XRD), rheology, confocal (CM) and scanning electron microscopy (SEM). Through FT-IR, the characteristic bands of functional groups corresponding to TEOS were confirmed. The CM results exhibit that UCNPs emit shorter wavelengths and, therefore, higher energy radiation. SEM images show the synthesized films have an irregular and porous surface. However, this behavior increases as the pH decreases and the temperature rises. From the viscoelastic analysis, the films show a stable structure within linear viscoelastic region. Also, their possible transition temperatures from a gel state to a glassy state are observed at 80 ºC.

In conclusion, the particles show upconversion properties and their morphology and size depend on heating time during synthesis. On the other hand, roughness, porosity and structural arrangement of films changes when the pH and temperature of system varied. The viscoelastic properties show stable structures. Finally, the material properties indicate their possible use in solar concentrators for plastic degradation.

Smart materials at the nanoscale level have seen significant advancements, leading to innovative applications in materials science and engineering. These materials are able to respond to physical, chemical, and/or biological stimuli. In particular, the behavior of sensitive polymer particles and their unique properties are strongly influenced by functional groups (GFs) attached to the main chain. For this reason, they can be used in several knowledge areas. The aim of this research is to synthesize Ph-thermo-responsive polymeric nanoparticles functionalized with carboxylic and amide groups by emulsion polymerization to be used as drug delivery systems. According to the methodology, series 1 (core–shell) and series 2 (core with concentration gradient) were prepared using a two-stage semicontinuous process and a power feed process, respectively. Polymers were characterized using dynamic light scattering (DLS), electrophoresis (zeta potential, ζ), and scanning electron microscopy (SEM), and viscosity (η) values, storage (G’) and loss (G’’) moduli were determined via rheological analysis. Measurements were performed in a temperature range of 25 ºC to 70 ºC. DLS analysis showed changes in the particle diameter (250≤Dz/nm≤1000) over the entire temperature range attributed to the phase transition temperatures. Negative zeta potential values (-45 ≤ ζ/mv ≤ -22) were observed, indicating high stability. As temperature rose, ζ approached zero, suggesting a loss of stability. Rheological tests revealed shear-thinning behavior for all polymers. Their elastic and viscous moduli provided insights into the linear viscoelastic regions and how yield points change with temperature variations. After a titration process, SEM images revealed distinct surface morphologies, including popcorn-like, cauliflower-like, and semi-spherical structures. In conclusion, the materials exhibit high sensitivity to temperature and pH changes, which induce conformational and morphological alterations influenced by the location and concentration of GFs within the particles. Therefore, they are suitable for use as nanocarries.

The combination of liquid crystals and nanotechnology has resulted in a variety of tunable multifunctional materials suitable for advanced nanophotonic applications, including miniature lasers, structured light, nonlinear optics, quantum technologies, sensing, imaging, communication, and soft robotics. The development of new nanocomposites made of liquid crystals and various types of nanoparticles is critical for future progress in this rapidly evolving field. Traditionally, conventional molecular liquid crystals are used as anisotropic hosts for nanomaterials to create advanced nonlinear optical materials. Recently, we proposed using glass-forming ionic liquid crystals made of metal alkanoates to produce glass nanocomposites exhibiting long-term stability and strong third-order nonlinear optical response. In this paper, we provide a comparative analysis of the nonlinear optical response of vitrified mesogenic cadmium octanoate containing gold, carbon, or both gold and carbon nanoparticles. Z-scan measurements, conducted using both nanosecond and femtosecond laser pulses, revealed an unusual nonlinear optical response in the studied materials. The measured values of the nonlinear absorption coefficients and nonlinear refractive indices are intensity-dependent. In addition, the excitation of the studied samples by nanosecond laser pulses can lead to the sign reversal of the nonlinear absorption coefficient, whereas the use of femtosecond laser pulses leads to sign reversal in the nonlinear refractive index. This sign reversal of nonlinear optical parameters depends on both light intensity and the composition of the studied nanocomposites. The obtained results can benefit the rapidly growing field of advanced nanophotonics, as they demonstrate different ways to control the effective nonlinear optical response of liquid crystal nanocomposites.

Nanoliposomes are systems composed of phospholipids or cholesterol that are used as carriers for topical delivery. Their formation, interaction, and stability depend on molecular organization and thermodynamics of self-assembly, describing how molecules spontaneously arrange into ordered structures by attractive or repulsive forces. These vesicles can encapsulate and transport substances, improving their stability, bioavailability, and skin penetration.

In this research, phosphatidylcholine (PC)-based nanoliposomes were prepared by ultrasonication at 25–40 °C. Lipid concentration ranged from 0.3 to 2.5 mM. Characterization included dynamic light scattering (DLS), zeta potential (ζ), scanning electron microscopy (SEM), and isothermal titration calorimetry (ITC). Thermodynamic parameters such as Gibbs free energy (ΔG°), enthalpy (ΔH°), and entropy (ΔS°) were determined using the following:

ΔG=−RTlnK

where R is the universal gas constant, T the absolute temperature, and K the equilibrium constant for lipid–lipid or lipid–additive interactions.

To describe micellization-related behavior, critical micelle concentration (CMC) and standard Gibbs energy of micellization were also considered using the following:

ΔGmic​=RTln(CMC)

According to the results, the most stable systems were found in a concentration range of 1.0 to1.2 mM, showing z values of -42.7 0.5 mV. This indicates a high stability. DLS measurements reported particle sizes between 115 and 135 nm with 1.1PDI. SEM images show spherical and homogeneous morphologies of liposomes, suggesting an efficient lipid packing and self-assembly. On the other hand, ITC experiments revealed exothermic binding profiles during formation. Thermodynamic analysis yielded negative values for enthalpy change (∆H° = -15 KJ/mol) at 25 ºC and 30 °C due to strong van der Waals and hydrophobic interactions. Nevertheless, positive values of ∆H° = 15 KJ/mol were obtained at 35 ºC and 40 °C attributed to a highly disordered structure. This indicates a reduced enthalpic contribution due to increased membrane fluidity. In summary, nanoliposomes could have a high potential to be used as nanocarriers in the cosmetic area.