Search Results (1,168)

Low-complexity domains (LCDs) are protein regions characterized by a simple amino acid composition and low sequence complexity, as they are typically composed of repeats or a limited set of a few amino acids. Historically dismissed as “garbage sequences”, these regions are now acknowledged as critical functional elements. This review systematically explores the structural characteristics, biological functions, pathological roles, and research methodologies associated with LCDs. Structurally, LCDs are marked by intrinsic disorder and conformational dynamics, with their amino acid composition (e.g., G/Y-rich, Q-rich, S/R-rich, P-rich) dictating structural tendencies (e.g., β-sheet formation, phase separation ability). Functionally, LCDs mediate protein–protein interactions, drive liquid–liquid phase separation (LLPS) to form biomolecular condensates, and play roles in signal transduction, transcriptional regulation, cytoskeletal organization, and nuclear pore transportation. Pathologically, LCD dysfunction—such as aberrant phase separation or aggregation—is implicated in neurodegenerative diseases (e.g., ALS, AD), cancer (e.g., Ewing sarcoma), and prion diseases. We also summarize the methodological advances in LCD research, including biochemical (CD, NMR), structural (cryo-EM, HDX-MS), cellular (fluorescence microscopy), and computational (MD simulations, AI prediction) approaches. Finally, we highlight current challenges (e.g., structural heterogeneity, causal ambiguity of phase separation) and future directions (e.g., single-molecule techniques, AI-driven LCD design, targeted therapies). This review provides a comprehensive perspective on LCDs, illuminating their pivotal roles in cellular physiology and disease, and offering insights for future research and therapeutic development. Full article

Eleven novel asymmetric pyrimidine derivatives were synthesized. The pyrimidine core was functionalized with a coumarin chromophore and a pro-mesogenic fragment bearing either chiral or linear alkyl chains of variable length and substitution patterns. The thermal properties were investigated using polarized optical microscopy, differential scanning calorimetry, and small-angle X-ray scattering, revealing that only selected derivatives exhibited liquid crystalline phases with ordered columnar or smectic organizations. Linear and nonlinear optical properties were characterized by UV–Vis absorption, fluorescence spectroscopy, two-photon absorption, and second-harmonic generation. Optical responses were found to be highly sensitive to the substitution pattern: derivatives functionalized at the 4 and 3,4,5 positions exhibited enhanced 2PA cross-sections and pronounced SHG signals, whereas variations in alkyl chain length exerted only a minor influence. Notably, compounds forming highly ordered non-centrosymmetric mesophases produced robust SHG-active thin films. Importantly, strong SHG responses were obtained without the need for a chiral center, as the inherent asymmetry of the linear alkyl chain derivatives was sufficient to drive self-organization into non-centrosymmetric materials. These results demonstrate that asymmetric pyrimidine-based architectures combining π-conjugation and controlled supramolecular organization are promising candidates for nonlinear optical applications such as photonic devices, multiphoton imaging, and optical data storage. Full article

The spontaneous formation and stability of a protective passive film on a metal surface are crucial for the metal material’s corrosion resistance during its service life. Passive films have been extensively studied, and our understanding of passive films has been significantly improved with the development of advanced analytical techniques. Modern synchrotron X-ray sources offer unprecedented possibilities for detailed analyses of passive films and for in situ and operando studies of passive films in both gaseous/aqueous environments, as well as in electrochemical environments. This mini review presents a short summary of recent studies on passive films, mainly focusing on stainless steels and nickel-base alloys, which utilize state-of-the-art synchrotron X-ray techniques, particularly X-ray photoelectron spectroscopy (XPS), often in combination with other synchrotron techniques such as X-ray adsorption, diffraction, reflectivity, and fluorescence. These reports demonstrate that synchrotron-based techniques greatly improve probing sensitivity and spatial resolution, enabling in situ and operando studies of passive films at solid–liquid interfaces. These studies reveal changes in the passive film and underlying alloy layer, highlighting the important role of hydroxides, as well as the inhomogeneity in passive films associated with the complex microstructures in advanced industrial alloys. Full article

Bisphenol A (BPA) is a synthetic estrogen widely used in the manufacture of food packaging materials, raising concerns due to its potential migration into food products. This study aims to determine BPA levels in pasteurized milk marketed in Algeria, using an easy-to-handle and efficient liquid–liquid extraction method coupled with liquid chromatography and fluorescence detection. A total of 30 pasteurized milk samples packaged in plastic were analyzed. The method validation demonstrated excellent linearity, with a limit of detection of 3.76 µg/L and a limit of quantification of 11.40 µg/L. Among the analyzed samples, 17 contained detectable BPA levels, ranging from not detectable to 24.07 µg/L, with an average concentration of 3.77 ± 5.77 µg/L, compliant with European regulation. The health risk assessment, based on estimated chronic daily intake and hazard index, indicated no significant risk associated with BPA exposure through milk consumption in the studied population. Additionally, the estrogenic equivalence of BPA in milk was 6.032 × 10⁻⁵ µgE₂/L, confirming a low estrogenic activity. Full article

In this study, zinc phthalocyanine (ZnPc) and copper phthalocyanine (CuPc) thin films fabricated by drop casting (DC) and close space sublimation (CSS) have been investigated and compared with ZnPc and CuPc solutions in formic acid (29 µmol/L). The results show that the CSS method produces films with improved molecular ordering, enhanced surface uniformity, superior optical and morphological properties compared to those obtained by drop casting. Moreover, CSS allows a precise and reproducible deposition, resulting in thinner, homogeneous layers with strong substrate adhesion and fewer defects. Optical characterization confirms that CSS films display high transparency (~90%), a sharp Q-band around 680 nm, and a fluorescence maximum at ~825 nm with the strongest emission intensity.In contrast, DC films show lower transparency (<70%), a slightly shifted Q-band (~675 nm), and similar emission around 825 nm. The fluorescence is strongly thickness-dependent: at ~100 nm, the emission band appears at 795 nm, while films thicker than 300 nm exhibit a red-shifted maximum at ~825 nm. AFM analysis further demonstrates the influence of deposition method: CSS yields smoother films with tunable morphology, while DC produces rougher, less controllable surfaces. Overall, CSS is shown to be the more effective approach for fabricating high-quality phthalocyanine films for optoelectronic applications such as photovoltaics and sensors. Full article

Chronic alcohol misuse is the leading cause of non-ischemic dilated cardiomyopathy, and the molecular mechanisms underlying the development of alcohol-associated cardiomyopathy (ACM), particularly regarding sex-specific susceptibility and mitochondrial contributions, are not fully known. In this study, we utilized a preclinical model of chronic + binge ethanol consumption to investigate sex differences in disease severity and mitochondrial function. Male and female C57BL/6J mice were fed ethanol or control liquid diets for 30 days, with 2 binge episodes on days 10 and 30. Cardiac morphology was assessed via echocardiography and cardiac function via left ventricular pressure–volume catheterization. Mitochondrial function was evaluated ex vivo using Seahorse XF analysis, ATP luminescence, and AmplexTM Red fluorescence in isolated ventricular mitochondria. Ethanol feeding induced significant cardiac dysfunction and increased transcriptional expression of inflammatory and fibrotic markers in males, while these effects were not seen in females. Despite these sex-specific cardiac effects, mitochondrial respiration, ATP production, collagen protein expression, and oxidative stress were not significantly altered following alcohol exposure in either sex. Further investigation is warranted to assess the potential role of ovarian hormones in this female cardioprotection against chronic + binge ethanol. Full article

Capsaicinoids (CPCs) are regarded as a typical marker of waste oil, which has emerged as a serious food safety issue in developing countries, necessitating the development of rapid, sensitive, and specific detection methods. In this study, a novel hapten was synthesized to generate a high-affinity monoclonal antibody (mAb) targeting CPCs. Subsequently, aggregation-induced emission fluorescent microspheres (AIEFMs), known for their superior fluorescence intensity, were utilized as an enhanced probe to develop a lateral flow immunoassay (LFIA) based on mAb 8B4 for CPC detection. For comparison, a traditional gold nanoparticle (AuNP)-LFIA was also constructed using the corresponding mAb. The AIEFM-LFIA demonstrated a limit of detection (LOD) of 0.33 µg/kg for CPCs in edible oil samples, which is 4.21 times lower than the LOD of 1.39 µg/kg achieved by the AuNP-LFIA. And the assay effectively identified three additional CPCs, with LODs ranging from 0.26 to 0.99 µg/kg, while exhibiting minimal cross-reactivity with CPC analogs, indicating high specificity. The recovery rates of the AIEFM-LFIA in oil samples ranged from 75.0% to 106.0%, with coefficients of variation ≤ 8.3%, exhibiting excellent accuracy and precision. Furthermore, the results of the AIEFM-LFIA demonstrated a strong degree of correlation with liquid chromatography–tandem mass spectrometry, with a correlation coefficient (R²) of 0.978. Consequently, the developed AIEFM-LFIA shows significant promise as a rapid, sensitive, specific, and reliable method for detecting CPCs in oil samples. Full article

While immune escape and physical invasion are two key pathways in tumor development, traditional methods for analyzing their exosomal markers are often complex and face identification bias. Microfluidic technology offers significant advantages for non-invasive liquid biopsy, particularly in the analysis of tumor progression markers carried by exosomes. Here, we developed an integrated microfluidic system for the sensitive, accurate, totally on-chip exosome isolation and automatic quantification of tumor progression markers PD-L1 and MMP9. This platform leverages microfluidic design principles for efficient sample mixing and monodisperses microbeads for precise analysis, allowing for complete processing within 40 min. The system’s high efficiency and precision are further enhanced by a lightweight YOLOv5-based positional migration strategy that automates fluorescence quantification. Validation using four different cell lines demonstrated distinct exosomal protein signatures with a low detection limit of 12.58 particles/μL. This innovative microfluidic chip provides a sensitive and easy-to-handle tool for exosomal marker analysis, holding great potential for cancer identification and personalized therapy guidance in the era of point-of-care testing (POCT). Full article

Background: Polyacrylamide gel electrophoresis (PAGE) has long been used for lipoprotein analysis, enabling the separation and profiling of lipoprotein fractions such as LDL and HDL. However, conventional disc PAGE systems are limited by low throughput and inability to directly compare multiple samples under identical conditions. Alternative methods, including high-performance liquid chromatography and agarose gel electrophoresis, require specialized equipment and expertise, limiting their clinical utility. Methods: We present a colorimetric and fluorescence-based histidine-imidazole PAGE (HI-PAGE) system that provides rapid, cost-effective, and reproducible separation and profiling of lipoproteins in human serum. By combining electrophoretic separation with lipid-specific fluorescent staining using Nile Red, the fluorescence-based HI-PAGE (fHI-PAGE) not only visualizes distinct migration patterns of lipoprotein fractions, but also enables the quantification of LDL-cholesterol (LDL-C). Clear resolution of LDL and other lipoprotein fractions was achieved within 1 h without band distortion, allowing for direct comparison of multiple samples on a single gel. Results: We validated fHI-PAGE using serum from healthy individuals and patients, demonstrating that its fluorescence-based detection was more sensitive than conventional Sudan Black B staining while providing LDL-C estimates concordant with values calculated by the Friedewald formula. Moreover, fHI-PAGE proved advantageous in cases of hypertriglyceridemia, where Friedewald calculations are unreliable. Conclusions: These findings establish fHI-PAGE as a practical and clinically applicable platform for simultaneous lipoprotein profiling and LDL-C quantification. Full article

Circulating heart-reactive autoantibodies (aAbs) detected in a variety of heart diseases (e.g., myocarditis, dilated cardiomyopathy, and myocardial infarction) have been associated with the progression of heart failure and a poor prognosis. However, the underlying mechanisms remain largely unknown. We investigated the effects of murine plasma containing aAbs against cardiac troponin I (cTnI) on neonatal rat cardiomyocytes (NRCMs). An autoimmune response to cTnI in A/J mice was induced, and anti-cTnI-aAbs were quantified. After 21 days, cardiac function, inflammation, fibrosis, and apoptosis were evaluated. In complementary in vitro liquid biopsy experiments, NRCMs were incubated with murine plasma containing high anti-cTnI-aAb levels or corresponding controls. Morphological phenotyping was performed using the C-MORE fluorescent image-based analysis workflow. Immunization with cTnI resulted in high anti-cTnI-aAb production, followed by myocardial inflammation, fibrosis, and impaired ejection fraction. NRCMs exposed to anti-cTnI-aAb-containing plasma showed reduced cell size, altered shape and radius, and elevated rate of dead cells in cell cycle analysis (p < 0.01, for 20% plasma). Together, these findings suggest a direct interaction of anti-cTnI-aAbs on cardiomyocytes, likely promoting adverse myocardial remodeling in vivo. Full article

Sake is a traditional Japanese alcoholic beverage that contains ethyl caproate (EC), a compound that enhances its economic value due to consumer preference. Procyanidins are polyphenolic compounds found in fruits such as apples, with procyanidin B2 (PB2) commonly used as a standard compound. Detecting EC and PB2 directly in intact or simply prepared beverages (e.g., dilution without organic solvent) requires liposomes as a model system. In this study, we focused on liquid-ordered/liquid-disordered liposomes, particularly reverse-domain liposomes, which were identified by fluorescence microscopy. EC and PB2 were found to increase and decrease the ratio of reverse-domain liposomes, respectively. The observation of cell-sized liposomes, combined with calibration curves, enabled a simplified analysis of EC and PB2. This approach has potential applications in the development, optimization, and practical implementation of food analytical methods for routine monitoring of beverage quality. These findings also provide a foundation for further studies on the biophysical and physiological properties of EC and PB2. Full article

Food safety hazards induce diverse cellular damages including DNA damage, oxidative stress, proteotoxic stress, and membrane disruption, ultimately contributing to various human diseases. Conventional toxicity assays, while effective, are often resource-intensive and lack the capacity to distinguish among these different damage types, thereby limiting insight into toxic responses and the development of effective strategies for targeted risk mitigation. Here, we constructed a panel of Escherichia coli whole-cell biosensors capable of distinguishing distinct categories of cellular damage. Specifically, an optimized RecA-LexA-based DNA damage biosensor that precisely controls the exogenous expression of the transcriptional repressor LexA achieved a 35.5% reduction in baseline signal and a 36.6-fold induction of fluorescence. In parallel, systematic promoter screening identified P_fpr, P_katG, P_grpE, and P_fabA as effective modules for constructing oxidative, proteotoxic, and membrane stress biosensors. These biosensors exhibited high specificity and sensitivity, generating dose-dependent responses to model toxicants and enabling discrimination of cellular damage induced by typical hazards such as norfloxacin and ciprofloxacin. Notably, the DNA damage biosensor detected norfloxacin with a limit of detection (LOD) of 1.3 ng/mL in standard solution and 3.0 ng/mL in milk, comparable to that of high-performance liquid chromatography (HPLC). Together, our work not only provides a versatile, cost-effective, and sensitive tool for assessing diverse cellular damages induced by food safety hazards, but also demonstrates potential utility for practical food safety monitoring. Full article

Diamorphine (DIM, heroin) is a semi-synthetic opioid that undergoes rapid conversion to 6-monoacetylmorphine and morphine, producing short-lived biomarkers that are difficult to capture during the process. This review critically explores the evolution of analytical techniques for quantitative DIM analysis in biological matrices from 1980 to 2025. It synthesizes findings across blood, plasma, urine, hair, sweat, and postmortem samples, emphasizing matrix-specific challenges and forensic applicability. Unlike previous opioid reviews that primarily focused on metabolites, this work highlights analytical methods capable of successfully detecting diamorphine itself alongside its key metabolites. This review examines 32 studies spanning three decades and compares three core analytical methods: gas chromatography–mass spectrometry (GC–MS), high-performance liquid chromatography (HPLC) with optical detection and liquid chromatography–mass spectrometry (LC–MS). Key performance metrics include sensitivity, sample preparation workflow, hydrolysis control, metabolite coverage, matrix compatibility, automation potential and throughput. GC–MS remains the workhorse for hair and sweat ultra-trace screening after derivatization. HPLC with UV, fluorescence or diode-array detection enables robust quantification of morphine and its glucuronides in pharmacokinetic and clinical settings. LC–MS facilitates the multiplexed analysis of DIM, its ester metabolites and its conjugates in a single, rapid run under gentle conditions to prevent ex vivo degradation. Recent advances such as high-resolution mass spectrometry and microsampling techniques offer new opportunities for sensitive and matrix-adapted analysis. By integrating validation parameters, forensic applicability, and evolving instrumentation, this review provides a practical roadmap for toxicologists and analysts navigating complex biological evidence. Full article

Lateral Flow Assays (LFAs) are ubiquitous test platforms due to their affordability and simplicity but are often limited by low sensitivity and lack of flow control. The present work demonstrates the combination of LFAs with centrifugal microfluidic platforms that allows for enhancement of LFAs’ sensitivity via the increase in the dwell time of the analyte at the test line as well as by passing a larger sample volume through the LFA strip. The rate of advancement of the liquid front in the radially positioned NC strip is retarded by the centrifugal force generated on spinning disc; therefore, the dwell time of the liquid front above the test line of LFA is increased. Additionally, integrating a waste reservoir enables passive replenishment of additional sample volume increases total probed volume by approximately 20% (from 50 μL to 60 μL). Comprehensive analysis, including COMSOL multiphysics simulation, was performed to deduce the importance of parameters such as channel height (100–300 μm), disc spin rate (0–2000 rpm), and reaction kinetics (fast vs. slow binding kinetics). The analysis was validated by the experimental observation of the slower-reacting CD79b protein on the test strip. For slower-reacting targets like CD79b, fluorescence intensity increased by ~40% compared to the static LFA. A new merit number, TRc (Transport Reaction Constant), is introduced, which refines the traditional Damköhler number (Da) by including the thickness of the liquid layer (such as the height of the microchannel), which affects the final sensitivity of the assays and is designed to reflect the role channel height plays for surface-based assays (in contrast to the bulk assays). Full article

Most botulinum toxin A (BoNT-A) products for esthetic use require reconstitution before administration. Ready-to-use relabotulinumtoxinA is a liquid manufactured using Precipitation-free Extraction and Activity-preserving, Refined Liquid (PEARL™) Technology from a proprietary C. botulinum type A1 strain. We examined the in vitro characteristics of relabotulinumtoxinA. The specific BoNT-A1 potency remained consistent throughout drug substance manufacturing (1.9 × 10⁸–2.2 × 10⁸ LD₅₀ mouse potency units/mg of BoNT-A1, four fractions sampled). Using glabellar line (GL) on-label doses, relabotulinumtoxinA liquid product was compared with powder onabotulinumtoxinA using the following: BoNT-A1 amount based on ELISA; specific enzyme activity based on SNAP-25 cleavage by a fluorescence resonance energy transfer-based assay (BoTest^®); biological activity (binding, internalization, and SNAP-25 cleavage over time) using a cell-based assay. RelabotulinumtoxinA contained more BoNT-A1 per on-label GL dose (0.27 ng) than onabotulinumtoxinA (0.18 ng), had higher enzyme activity (53 vs. 29 BoTest^® units) per GL dose, and had higher specific activity per pg BoNT-A, with onabotulinumtoxinA displaying 81% of the specific activity of relabotulinumtoxinA. In vitro, relabotulinumtoxinA demonstrated higher biological activity and earlier onset of SNAP-25-cleavage than onabotulinumtoxinA. PEARL^TM Technology thus produces high-quality BoNT-A1 with high specific enzyme and biological activities, which may explain the clinical performance of relabotulinumtoxinA in Phase 3 clinical trials examining treatment of GLs and/or LCLs. Full article