Search Results (277)

Cell-free biosensors harness the selectivity of cellular machinery without living cells’ constraints, offering advantages in environmental monitoring, medical diagnostics, and biotechnological applications. This review examines recent advances in cell-free biosensor development, highlighting their ability to detect diverse analytes including heavy metals, organic pollutants, pathogens, and clinical biomarkers with high sensitivity and specificity. We analyze technological innovations in cell-free protein synthesis optimization, preservation strategies, and field deployment methods that have enhanced sensitivity, and practical applicability. The integration of synthetic biology approaches has enabled complex signal processing, multiplexed detection, and novel sensor designs including riboswitches, split reporter systems, and metabolic sensing modules. Emerging materials such as supported lipid bilayers, hydrogels, and artificial cells are expanding biosensor capabilities through microcompartmentalization and electronic integration. Despite significant progress, challenges remain in standardization, sample interference mitigation, and cost reduction. Future opportunities include smartphone integration, enhanced preservation methods, and hybrid sensing platforms. Cell-free biosensors hold particular promise for point-of-care diagnostics in resource-limited settings, environmental monitoring applications, and food safety testing, representing essential tools for addressing global challenges in healthcare, environmental protection, and biosecurity. Full article

This study developed phospholipid-based liposomes loaded with extract from wild thyme (Thymus serpyllum L.) tea processing residues to enhance polyphenol stability and delivery. Liposomes were prepared with phospholipids alone or combined with 10–30 mol% cholesterol or β-sitosterol. The effect of different lipid compositions on encapsulation efficiency (EE), particle size, polydispersity index (PDI), zeta potential, stability, thermal properties, diffusion coefficient, and diffusion resistance of the liposomes was investigated. Liposomes with 10 mol% sterols (either cholesterol or β-sitosterol) exhibited the highest EE of polyphenols, while increasing sterol content to 30 mol% resulted in decreased EE. Particle size and PDI increased with sterol content, while liposomes prepared without sterols showed the smallest vesicle size. Encapsulation of the extract led to smaller liposomal diameters and slight increases in PDI values. Zeta potential measurements revealed that sterol incorporation enhanced the surface charge and stability of liposomes, with β-sitosterol showing the most pronounced effect. Stability testing demonstrated minimal changes in size, PDI, and zeta potential during storage. UV irradiation and lyophilization processes did not cause significant polyphenol leakage, although lyophilization slightly increased particle size and PDI. Differential scanning calorimetry revealed that polyphenols and sterols modified the lipid membrane transitions, indicating interactions between extract components and the liposomal bilayer. FT-IR spectra confirmed successful integration of the extract into the liposomes, while UV exposure did not significantly alter the spectral features. Thiobarbituric acid reactive substances (TBARS) assay demonstrated the extract’s efficacy in mitigating lipid peroxidation under UV-induced oxidative stress. In contrast, liposomes enriched with sterols showed enhanced peroxidation. Polyphenol diffusion studies showed that encapsulation significantly delayed release, particularly in sterol-containing liposomes. Release assays in simulated gastric and intestinal fluids confirmed controlled, pH-dependent polyphenol delivery, with slightly better retention in β-sitosterol-enriched systems. These findings support the use of β-sitosterol- and cholesterol-enriched liposomes as stable carriers for polyphenolic compounds from wild thyme extract, as bioactive antioxidants, for food and nutraceutical applications. Full article

100 nm thick TiO₂/TiN bilayers with varying thickness ratios were deposited via reactive sputtering of a Ti target in controlled oxygen and nitrogen atmospheres. Post-deposition annealing in air at 600 °C was performed to induce nitrogen diffusion through the oxygen-deficient TiO₂ layer. The resulting changes in morphology and chemical environment were investigated in detail using transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and UV-Vis spectroscopy. Detailed TEM and XPS analyses have confirmed nitrogen diffusion across the TiO₂ layer, with surface nitrogen concentration and the ratio of interstitial to substitutional nitrogen dependent on the TiO₂/TiN mass ratio. Optical studies demonstrated modifications in optical constants and a reduction of the effective bandgap from 3.2 eV to 2.6 eV due to new energy states introduced by nitrogen doping. Changes in surface free energy induced by nitrogen incorporation showed a correlation to nitrogen doping sites on the surface, which had positive effects on overall photocatalytic activity. Photocatalytic activity, assessed through methylene blue degradation, showed enhancement attributed to nitrogen doping. Additionally, deposition of a 5 nm gold layer on the annealed sample enabled investigation of synergistic effects between nitrogen doping and gold incorporation, resulting in further improved photocatalytic performance. These findings establish the TiO₂/TiN bilayer as a versatile platform for supporting thin gold films with enhanced photocatalytic properties. Full article

The multi-domain muscle protein titin provides elasticity and mechanosensing functions to the sarcomere. Titin’s PEVK domain is intrinsically disordered due to the presence of a large number of prolines and highly charged residues. Although PEVK does not have canonical actin-binding motifs, it has been shown to bind F-actin. Here, we explored whether the PEVK domain may also affect actin assembly. We cloned the middle, 733-residue-long segment (called PEVKII) of the full-length PEVK domain, expressed in E. coli and purified by using His- and Avi-tags engineered to the N- and C-termini, respectively. Actin assembly was monitored by the pyrene assay in the presence of varying PEVKII concentrations. The structural features of PEVKII-associated F-actin were studied with atomic force microscopy. The added PEVKII enhanced the initial and log-phase rates of actin assembly and the peak F-actin quantity in a concentration-dependent way. However, the critical concentration of actin polymerization was unaltered. Thus, PEVK accelerates actin polymerization by facilitating its nucleation. This effect was highlighted in the AFM images of F-actin–PEVKII adsorbed to the supported lipid bilayer. The sample was dominated by radially symmetric complexes of short actin filaments. PEVK’s actin polymerization-modulating effect may, in principle, have a function in regulating sarcomeric actin length and turnover. Altogether, titin’s PEVK domain is not only a non-canonical actin-binding protein that regulates sarcomeric shortening, but one that may modulate actin polymerization as well. Full article

Hydroxyapatite (HA) has become a widely used material for bone grafting and surface modification of titanium-based orthopedic implants due to its excellent biocompatibility. Among various coating techniques, microplasma spraying (MPS) has gained significant industrial relevance. However, the clinical success of HA coatings also depends on their adhesion to the implant substrate. Achieving durable fixation and reliable biological integration of orthopedic implants remains a major challenge due to insufficient coating adhesion and limited osseointegration. This study addresses challenges in dental and orthopedic implantology by evaluating the microstructure, mechanical properties, and biological behavior of bilayer coatings composed of a zirconium (Zr) sublayer and an HA top layer, applied via MPS onto titanium alloy. Surface roughness, porosity, and adhesion were characterized, and pull-off and shear tests were used to assess mechanical performance. In vitro biocompatibility was tested using rat mesenchymal stem cells (MSCs) to model osteointegration. The results showed that the MPS-fabricated Zr–HA bilayer coatings achieved a pull-off strength of 28.0 ± 4.2 MPa and a shear strength of 32.3 ± 3.2 MPa, exceeding standard requirements. Biologically, the HA top layer promoted a 45% increase in MSC proliferation over three days compared to the uncoated titanium substrate. Antibacterial testing also revealed suppression of E. coli growth after 14 h. These findings support the potential of MPS-applied Zr-HA coatings to enhance both the mechanical integrity and biological performance of titanium-based orthopedic implants. Full article

Janus nanoparticles (JNPs) extend the concept of amphiphilicity beyond classical molecular surfactants into the nanoscale. Amphiphilic behavior is defined by the presence of hydrophobic and hydrophilic moieties within a single molecular structure. Traditionally, such molecular structures are known as surfactants or amphiphiles and are capable of reducing interfacial tension, adsorbing spontaneously at interfaces, stabilizing emulsions and foams, and forming micelles, bilayers, or vesicles. Recent experimental, theoretical, and computational studies demonstrate that these behaviors are scalable to nanostructured colloids such as JNPs. Amphiphilic JNPs, defined by anisotropic surface chemistry on distinct hemispheres, display interfacial activity driven by directional wetting, variable interfacial immersion depth, and strong interfacial anchoring. They can stabilize liquid/liquid and liquid/gas interfaces, and enable templated or spontaneous self-assembly into supra-structures, such as monolayer sheets, vesicles, capsules, etc., both in bulk and at interfaces. Their behavior mimics the “soft” molecular amphiphiles but also includes additional particularities given by their “hard” structure, as well as contributions from capillary, van der Waals, hydrophobic, and shape-dependent forces. This review focuses on compiling the evidence supporting amphiphilicity as a scalable property, discussing how JNPs function as colloidal amphiphiles and how geometry, polarity contrast, interfacial interactions, and environmental parameters influence their behavior. By comparing surfactant behavior and JNP assembly, this work aims to clarify the transferable principles, the knowledge gap, as well as the emergent properties associated with amphiphilic Janus colloids. Full article

In this study, an innovative dental functionalized magnetic nanomaterial was developed by incorporating hydrophilic magnetic clusters as an alternative to conventional isolated magnetic nanoparticles, introducing a novel structural and functional concept in dental applications. The ~100 nm magnetic clusters—composed of densely packed 7 nm Fe₃O₄ nanoparticles—were sequentially coated with a silica (SiO₂) layer (3–5 nm) to improve chemical and mechanical stability, followed by an outer calcium hydroxide [Ca(OH)₂] layer to enhance bioactivity and optical integration. This bilayer architecture enables magnetic field-assisted positioning and improved dispersion within dental resin matrices. Silver nanoparticles were incorporated to enhance antimicrobial activity and reduce biofilm formation. The synthesis process was environmentally friendly and scalable. Comprehensive physicochemical characterization confirmed the material’s functional performance. Saturation magnetization decreased progressively with surface functionalization, from 62 to 14 emu/g, while the zeta potential became increasingly negative (from −2.42 to −22.5 mV), supporting its ability to promote apatite nucleation. The thermal conductivity (0.527 W/m·K) closely matched that of human dentin (0.44 W/m·K), and the colorimetric analysis showed improved brightness (ΔL = 5.3) and good color compatibility (ΔE = 11.76). These results indicate that the functionalized magnetic nanomaterial meets essential criteria for restorative use and holds strong potential for future clinical applications. Full article

Squid skin decellularized dermal matrix (SADM) is gaining attention in tissue engineering and regenerative medicine due to its mimicking of the extracellular matrix property. Hence, SADM was used to investigate mimicking the microenvironment of cellular growth, inducing cellular infiltration and angiogenesis, and facilitating the repair of acute craniofacial wounds. For this, tissue regeneration membranes from squid skin were prepared by decolorization, degreasing and decellularisation methods. The effect of SADM in guiding bone tissue regeneration was evaluated using the rabbit skull bone defect model. SEM images of SADM had a bilayer membrane architecture characterized by a reticulated porous structure on one side and a dense, non-porous surface on the opposite side. Notably, the water absorption capacity of SADM was approximately eight times higher than its weight, exhibiting a porosity of 58% and a peak average tensile stress of 10.43 MPa. Additionally, simulations of tissue fluid degradation indicated a degradation rate of 70.42% and 88.33% on days 8 and 12, respectively. Following 4 and 8 weeks of animal studies focused on repairing cranial bone defects in rabbits, the findings demonstrated that SADM served as an effective barrier against fibrous connective tissue, promoted the proliferation of osteoblasts, and supported bone regeneration. This was confirmed through micro-CT imaging, and sections were stained with senna solid green. In summary, SADM is capable of directing cell infiltration and bone tissue formation, modulating the expression and secretion of inflammatory and skin repair-related factors, thereby enhancing tissue healing. Full article

Efficient evolution exists before DNA, else the DNA genome itself could not evolve. Current data suggest RNA-membranes for this role. Selected RNAs bind well to phospholipid bilayers; randomized sequences do not. No repeated sequences are evident in selected binding RNAs. This implies small and varied membrane-affinity motifs. Such binding sequences are partially defined. Phospholipid-bound RNAs require divalents like Mg²⁺ and/or Ca²⁺, preferring more ordered bilayers: gel, ripple, or rafted membranes, in that order. RNAs also bind and stabilize bent or sharply deformed bilayers. RNA binding without divalents extends to negatively charged membranes formed from simpler anionic phospholipids and to plausibly prebiotic fatty acid bilayers. RNA-membranes frequently retain RNA solution functions: base pairing, passive transport of tryptophan, specific affinity for arginine side chains, and ribozymic ligase catalysis. Membrane-bound RNAs with several biochemical functions, linked by specific base-pairing, are readily constructed. Given these data, genetic roles seem feasible. RNA activities often require few nucleotides, easily joined in a small RNA. Base-paired groups of such RNAs can also be purposeful, joining related functions. Complex functions can therefore require only replication of short RNAs. RNA-membranes potentially segregate accurately during cell division and quickly evolve through new base pairings. Accordingly, ancient RNA-membranes could act as a protogenome, supporting encoded RNA expression, inheritance, and evolution before the DNA genome: for example, supporting organized biochemistry, coded translation, and a Standard Genetic Code. Full article

A novel bi-layered scaffold, obtained via 3D printing and electrospinning, was designed to improve osteochondral region reconstruction. The upper electrospun membrane will act as a barrier against unwanted tissue infiltration, while the lower 3D-printed layer will provide a porous structure for tissue ingrowth. Graphene was integrated into the scaffold for its antibacterial properties, and the drug Osteogenon^® (OST) was added to promote bone tissue regeneration. The composite scaffolds were subjected to comprehensive physical, thermal, and mechanical evaluations. Additionally, their biological functionality was assessed by means of NHAC-kn cells. The 0.5% graphene addition to PCL significantly increased strain at break, enhancing the material ductility. GNP also acted as an effective nucleating agent, raising crystallization temperatures and supporting mineralization. The high surface area of graphene facilitated rapid apatite formation by attracting calcium and phosphate ions. This was confirmed by FTIR, µCT and SEM analyses, which highlighted the positive impact of graphene on mineral deposition. The synergistic interaction between graphene nanoplatelets and Osteogenon^® created a bioactive environment that enhanced cell adhesion and proliferation, and promoted superior apatite formation. These findings highlight the scaffold’s potential as a promising biomaterial for osteochondral repair and regenerative medicine. Full article

Osteochondral defects, involving both articular cartilage and subchondral bone, pose significant challenges to joint function and health due to the lack of spontaneous healing and the risk of long-term degenerative diseases like osteoarthritis. Biomaterials have emerged as important components in the development of scaffolds, providing structural support that facilitates tissue growth, integration, and regeneration. This study aims to demonstrate the effectiveness of a tomographic assessment method for optimizing the evaluation of osteochondral regeneration, particularly using Hounsfield units, to enable the evaluation of scaffold integration and tissue regeneration. The sheep model was selected as a model study. Two distinct configurations of biomaterials were utilized in this study: Honey (HMG—Mg doped hydroxyapatite; HWS—wollastonite–hydroxyapatite) and Bi-layer (BWS—wollastonite–hydroxyapatite). The HMG scaffold demonstrated superior integration, reparative tissue quality, and regeneration potential compared to the HWS, BWS, and CTRL groups. The findings underscore the significance of CT assessment as a preliminary method for evaluating hard tissue, such as bone, employing Hounsfield units. Statistical evaluations validated the significant differences in performance, particularly favoring the HMG group. The results of this study underscore the importance of tomographic assessment in evaluation of osteochondral regeneration. Full article

Background: Organ transplant recipients are at a significantly higher risk of developing skin cancer compared to the general population, particularly cutaneous squamous cell carcinoma. Approximately 3–8% of these carcinomas are located on the scalp. Scalp reconstruction is particularly challenging, especially for large excisions, due to the thickness of the scalp, the inelastic aponeurosis of the galea, and the integrity of the hair-bearing scalp. Additionally, in organ transplant recipients, the presence of numerous comorbidities and the increased risk of infection due to immunosuppressive therapy make management more complex. Based on our experience and the existing literature, we aim to describe possible reconstruction methods and discuss the combined management of medical and immunosuppressive therapy. Method: We present our experience with seven kidney transplant patients who underwent excision of cutaneous squamous cell carcinoma with a diameter larger than 3 cm. The crane technique involves three key steps. First, the tumor is excised with wide margins of disease-free tissue. Next, a pericranial flap is rotated and positioned to cover the exposed cranial bone. Finally, a bilayer dermal substitute is applied to create a microenvironment that supports skin graft implantation. Results: The crane technique was used for six patients. In one case, an O-Z rotation flap was used. All patients modified their immunosuppressive therapy, with those receiving antiproliferative therapy switching everolimus after surgery. Conclusions: When combined with a post-operative modification of the immunosuppressive regimen, the crane technique could be considered a feasible, safe, and effective approach to managing large cSCC of the scalp in fragile patients. Full article

Supported lipid bilayers (SLBs) that model neuronal membranes are needed to explore the role of membrane lipids in the misfolding and aggregation of amyloid proteins associated with neurodegenerative diseases, including Parkinson’s and Alzheimer’s disease. The neuronal membranes include not only phospholipids, but also significant amounts of cholesterol, sphingomyelin, and gangliosides, which are critical to its biological function. In this study, we explored the conditions for the formation of an SLB, for the five-component lipid mixture composed of zwitterionic 1,2-Dioleoyl-sn-glycero-3-phosphocholine (DOPC), anionic 1,2-dioleoyl- sn-glycero-3-phospho-L-serine (DOPS), nonionic cholesterol (Chol), zwitterionic sphingomyelin (SM), and anionic ganglioside (GM), using the quartz crystal microbalance with dissipation monitoring (QCM-D) technique, by varying experimental parameters such as pH, buffer type, temperature, vesicle size, and osmotic stress. SLB formation from this multicomponent lipid system was found challenging because the vesicles adsorbed intact on the quartz crystal and failed to rupture. For most of the variables tested, other than osmotic stress, we found no or only partial vesicle rupture leading to either a supported layer of vesicles or a partial SLB that included unruptured vesicles. When osmotic stress was applied to the vesicles already adsorbed on the surface, by having a different salt concentration in the rinse buffer that follows vesicle flow compared to that of the dilution buffer during vesicle flow and adsorption, vesicle rupture increased, but it remained incomplete. In contrast, when osmotic stress was applied during vesicle flow and adsorption on the surface, by having different salt concentrations in the dilution buffer in which vesicles flowed compared to the hydration buffer in which vesicles were prepared, complete vesicle rupture and successful formation of a rigid SLB was demonstrated. The robustness of this approach to form SLBs by applying osmotic stress during vesicle adsorption was found to be independent of the number of lipid components, as shown by SLB formation from the 1-, 2-, 3-, 4-, and 5-component lipid systems. Full article

Various pathogens use receptors on the host’s plasma membrane for their cellular uptake. For the bacterium Pseudomonas aeruginosa, interactions between its lectin LecA and the host cell glycosphingolipid globotriaosylceramide (also known as Gb3) are crucial for its internalization via the so-called lipid zipper mechanism. In this study, we investigated the interactions of the P. aeruginosa strain PAO1 with phase-separated lipid bilayers containing Gb3. Surprisingly, bacteria are mostly bound to the interphase of liquid-ordered (Lo) and liquid-disordered (Ld) membrane domains. Simultaneously with the formation of bacterial aggregates and the accumulation of membrane lipids, the lipid bilayers were drastically reorganized and Lo domains were dissolved. Surprisingly, Gb3 was found to play a role in the localization of the bacterium at the interface, less so LecA. When microspheres were used as a minimal mimic of the bacterium, these beads also localized preferentially at the Lo–Ld phase boundaries, but in contrast to living bacteria, beads were unable to cause membrane reorganization and dissolution of the Lo domain, even when coated with LecA. Targeting phase boundaries as “weak points” in membranes and thereby reorganizing and destabilizing the host cell plasma membrane could be an attractive entry strategy for P. aeruginosa and many other bacteria and viruses. Full article

Water in membrane interphases is vital for cellular biological functions, but despite its importance, the structure and function of biological water remain elusive. Here, by studying the OH stretching mode in partially hydrated lipid multilayers by FTIR measurements, relevant information on the water structure near the surface with lipid membranes has been gathered. The water hydrogen bond network is highly perturbed in the first layers that are in contact with the lipid membrane, exhibiting strong deviations from tetrahedral symmetry and a significant number of defects, such as isolated water molecules and a large number of hydrogen-bonded water dimers in the interphase region. These findings support the hypothesis that water chains form in phospholipid membranes, and are involved in the proton transfer across lipid bilayers by phosphate groups of opposing lipids. Furthermore, we have determined that even at very low hydration levels, a small amount of water is embedded within the confined spaces of the hydrocarbon region of phospholipid bilayers, which could potentially contribute to the structural stability of the lipid membrane. Full article