Search Results (822)

In this paper, we have synthesized silicon nanoparticles (SiNPs) via a simple, scalable hydrothermal method using [3-(2-aminoethylamino)propyl] trimethoxysilane (AEAPTMS) as the Si precursor and L-ascorbic acid (L-AA) as the reductant. In order to improve carrier transport in the synthesized NPs to enhance their applicability in optoelectronic devices, a surface modification process had been carried out to replace the original long-chain dehydroascorbic acid (DHA) ligand with a shorter-chain 3-mercaptopropionic acid (MPA) ligand. A hybrid test structure was then fabricated composed of the surface-modified SiNP layer with a conductive polymer, PEDOT:PSS, which served as the hole transport layer. This SiNP-PEDOT:PSS planar heterostructure served as a platform to probe the photoresponse and carrier dynamics of the modified nanoparticles. Compared to the as-synthesized SiNPs, the surface-modified SiNPs achieved a 20% increase in carrier lifetime and an on/off ratio of 7.28 at ±1 V applied bias under UV illumination. These findings highlight the potential of SiNPs for integration into solution-processed optoelectronic devices. Full article

Native Staphylococcus aureus protein A exhibits strong affinity to the Fc and VH regions of human IgG1, IgG2, and IgG4, making it a valuable tool for monoclonal antibody (mAb) purification. However, its low stability under conditions such as increased alkaline concentrations during cleaning-in-place (CIP), protease exposure, thermal stress, and shear forces limits its usability for large-scale industrial applications. Recombinant Protein A (rProtein A) can be modified to improve key properties, including alkaline stability. In this study, we present targeted modifications to the C domain of native Protein A, evaluating multimeric variants for structural and functional improvements. The selected variant demonstrated extremely high stability after 60 h incubation at 0.5 M NaOH by maintaining more than >90% initial dynamic binding capacity (DBC) and up to 80% DBC after 40 h in 1.0 M NaOH. However, the most impressive result obtained was the stability of the ligand in 1.5 M NaOH, retaining 80% DBC after 22 h and 60% DBC after 40 h. To the best of our knowledge, this is the first time that such high alkaline stability is reported for a rProtein A. To assess its application in monoclonal antibody purification, the optimized rProtein A ligand was immobilized on agarose resin and tested in chromatography processes. The resulting chromatography resin functionalized with the CmZmb ligand (now commercialized by Sunresin, China under the name of rProtein A Seplife Suno) exhibited a high dynamic binding capacity of 70 mg/mL, minimal ligand leaching under operational conditions (~15 ppm), and extended lifecycle performance (88% DBC retained after 120 purification cycles with 0.5 M NaOH CIP), making it well-suited for industrial-scale applications. Full article

Background: Protein A resins are indispensable for monoclonal antibody (mAb) production, yet their condition and performance are traditionally assessed using indirect or qualitative methods. In this study, the multi-attribute method (MAM), previously applied to therapeutic protein characterization, is systematically adapted for the first time as a unified liquid chromatography–mass spectrometry (LC-MS) platform for Protein A resin analysis. Method: Four Cytiva Protein A resins, MabSelect™, MabSelect SuRe™, MabSelect SuRe™ LX, and MabSelect™ PrismA, were evaluated by MAM for resin identity, Protein A ligand integrity, fouling by impurities, and cleaning performance. Results: MAM enables resin-specific peptide fingerprinting and quantitative monitoring of Protein A ligand post-translational modifications (PTMs), including deamidation, isomerization, and fragmentation induced by repeated clean-in-place (CIP) cycles. Comparative analysis of virgin and used resins revealed ligand degradation and fouling despite engineered alkaline stability, with MabSelect™ showing the greatest susceptibility. Importantly, residual monoclonal antibodies (mAbs) and host cell proteins (HCPs) were directly detected and quantified from the resin matrix, providing a molecular-level assessment of resin cleaning effectiveness not achievable with conventional approaches. Conclusions: This work establishes MAM as a novel, sensitive, and comprehensive strategy for Protein A resin lifecycle management, delivering actionable insight for resin selection, cleaning optimization, and downstream process development. Full article

The immunosuppressive nature of porcine reproductive and respiratory syndrome virus (PRRSV) remains the central obstacle to its effective control. Conventional microRNA (miRNA)-based antiviral approaches are limited by their modest potency and the high risk of viral escape. Here, we rationally designed an engineered miRNA carrying a 5′-triphosphate (5′-PPP) terminus that integrates RIG-I-driven innate immune activation and sequence-specific gene silencing within a single molecule. In vitro-transcribed 5′-PPP miRNAs are efficiently recognized by the pattern-recognition receptor RIG-I, triggering a robust type I interferon response that counteracts PRRSV-induced immunosuppression. In MARC-145 cells, one such construct, 5′-PPP BZL-sRNA-20, potently inhibited PRRSV replication through the synergistic action of immune activation and gene silencing. However, in porcine alveolar macrophages (PAMs)—the natural host cells for PRRSV—the antiviral effect depended primarily on 5′-PPP-induced interferon responses, with the targeting sequence providing limited or context-dependent benefits. Dual-luciferase assays confirmed that the gene-silencing activity depends on 5′-PPP modification, which enhances the stability of BZL-sRNA-20. This bifunctional strategy establishes an “immune activation plus targeting” paradigm by simultaneously acting as a RIG-I ligand that triggers broad antiviral responses and specifically cleaves viral RNA via direct base-pairing to conserved regions of the PRRSV genome. These findings reveal the potential of engineered 5′-PPP miRNAs as immunomodulatory antiviral agents, while highlighting that the contribution of RNAi targeting varies depending on the cellular context. Full article

Silica-supported zinc (II)–Schiff-base complexes were prepared through a simple and high-yield immobilization strategy and evaluated as heterogeneous catalysts for the ring-opening polymerization (ROP) of lactide. Silica gel and silica nanoparticles were employed as supports to assess the influence of support morphology and textural properties on catalytic performance. Comprehensive characterization by AAS, BET, SEM, and SEM–EDS confirmed effective anchoring of the Zn complexes, homogeneous metal distribution, and support-dependent textural modifications. The supported catalysts were active in the bulk ROP of racemic and enantiopure lactide, affording PLA with high conversions and moderate dispersities. Silica-gel-supported systems exhibited high and reproducible activity over a wide range of conditions, whereas catalysts supported on silica nanoparticles showed a stronger dependence on reaction time and ligand electronic effects, highlighting the key role of the support in modulating active site accessibility and chain growth. Microstructural and thermal analyses confirmed the formation of atactic PLA from rac-lactide and stereoregular PLLA from L-lactide. Overall, this study demonstrates that silica-supported zinc(II)–Schiff-base complexes constitute an effective and versatile heterogeneous platform for lactide ROP and underscore the importance of support properties in the rational design of sustainable catalysts for biodegradable polyester synthesis. Full article

The berberine derivative 13-(2-methylbenzyl)-berberine (BED) has been shown to inhibit the MexXY-OprM efflux system of Pseudomonas aeruginosa (PA), a key contributor to aminoglycoside resistance, by interacting with the inner membrane protein MexY at an allosteric pocket (ALP). To enhance binding efficacy, this study aims to identify novel chemical scaffolds that target the MexY allosteric pocket through an integrated computational strategy. In this work, a ligand-based virtual screening (LBVS) approach was employed using a 2D/3D pharmacophore model derived from BED to perform in silico screening of an Enamine compound library, which encompasses a broad and diverse chemical space. A key objective was to compare the predictive performance of this pharmacophore-based workflow with a structure-based (SB) strategy incorporating molecular docking and molecular dynamics (MD) simulations. Notably, the top-ranked LBVS hits were consistently validated by docking and MD analyses, showing stable binding and interaction patterns comparable or superior to those of BED. This convergence between ligand-based (LB) and SB methods highlights the internal coherence of the workflow and supports the robustness of the pharmacophore hypothesis. The identified scaffolds generally displayed high hydrophobicity, consistent with the physicochemical nature of the binding site, but resulting in limited aqueous solubility and complicating their experimental evaluation. While these features confirm the importance of hydrophobic interactions in MexY recognition, with a particular focus on some few residues, such as Phe560, it also underscores the need for formulation strategies or rational scaffold modifications introducing moderate polarity without weakening key contacts. Overall, the integrated computational strategy not only yields promising lead chemical structures but also provides a solid basis for their future optimization, ultimately supporting the design of new efflux pump inhibitors (EPIs) capable of contributing to improved antibiotic susceptibility in multidrug-resistant PA strains. Full article

The ability to assess molecular binding kinetics in real time is critical for advancing our understanding of molecular interactions in biochemical and biotechnological systems. This work presents a novel optical tweezer (OT)-based method to monitor molecular affinity in real time, focusing on the high-affinity streptavidin–biotin system as a model. Transparent poly(methyl methacrylate) (PMMA) microparticles functionalized with streptavidin were trapped before, during, and after binding with biotinylated bovine serum albumin (biotin–BSA), enabling the analysis of forward-scattered signals to detect nanoscale changes in particle size. By applying the Power Spectral Density method, the friction coefficient of individual particles was calculated, allowing for real-time tracking of binding dynamics and the estimation of the association rate constant ($k_{\mathrm{on}}\approx {10}^6{\mathrm{M}}^{-1}{\mathrm{s}}^{-1}$). These results are consistent with literature values and demonstrate the potential of this OT-based approach for non-invasive, label-free detection of molecular interactions. Compared to existing techniques, such as atomic force microscopy and cantilever-based sensors, this method offers significant advantages, including real-time monitoring, adaptability to different bioaffinity systems, and compatibility with miniaturized setups. This work establishes a foundation for using OT-based tools to monitor high-affinity molecular interactions in real time. While demonstrated here using biotinylated BSA as a model ligand, future studies will explore the method’s applicability to smaller ligands and more subtle surface modifications. Full article

Gadolinium nanoparticles (GdNPs) have gained increasing attention as multifunctional metal-based nanoplatforms that extend far beyond their traditional use as magnetic resonance imaging (MRI) contrast agents. Their specific magnetic properties, tunable physicochemical features, and tunable biocompatibilities with biocompatible coatings give them great potential as drug delivery and theranostic applications. They offer greater stability, lower systemic toxicity, and more surface modification options compared to molecular gadolinium chelates. The functionalized GdNPs not only show excellent properties as drug carriers for their specific indications but also serve as agents in various imaging modalities with superior therapeutic efficacy by means of radio sensitization and magnetically assisted delivery. Note too that GdNP-based formulations have demonstrated synergistic activity when administered with chemotherapeutic agents such as doxorubicin. GdNPs have demonstrated promising preclinical outcomes, and their clinical translation remains restricted due to a number of scale-up constraints, long-term safety challenges, pharmacokinetics, and regulatory problems. This review provides information on the use of GdNPs, their key physicochemical and magnetic properties, ligand engineering for targeted delivery, and biological mechanisms of their theranostic performance. Full article

Vitamin D signaling via the vitamin D receptor (VDR) regulates calcium–phosphate homeostasis and extensive gene programs controlling cell proliferation, differentiation, immune tone, and metabolism. However, systemic use of the natural agonist 1α,25-dihydroxyvitamin D₃ (calcitriol) for extraskeletal indications is limited by dose-limiting hypercalcemia. This review summarizes VDR biology and the structural basis of ligand action, emphasizing how ligand-induced repositioning of helix 12 and altered coregulator recruitment can be exploited to engineer selective VDR modulators. We highlight medicinal chemistry strategies spanning secosteroidal analogs with side-chain or ring modifications and emerging non-seco scaffolds and discuss clinically established agents (e.g., calcipotriol and paricalcitol) alongside experimental “super-agonists”, partial agonists, and antagonists designed to widen the therapeutic window. Finally, we discuss current evidence for VDR targeting across cancer, metabolic disease, fibrosis, and immune-inflammatory disorders, including mechanisms of resistance such as dysregulated vitamin D metabolism and epigenetic repression. Structural and epigenomic insights are positioning next-generation VDR ligands as tissue- and pathway-biased therapeutics that may enable safer, mechanism-guided translation beyond bone and mineral indications. Full article

Background: There is currently increasing interest in atypical opioid compounds capable of expanding their clinical applications beyond pain management, including the treatment of psychiatric disorders and substance abuse. In this context, the cyclotetrapeptide c[Trp-Phe-D-Pro-Phe] (CJ-15,208, 1) and its derivatives represent an unusual class of opioid peptides. This compound was found to be a mixed KOR/MOR antagonist in vitro, but it acted as an agonist in vivo. For its diverse analogues, it appeared that receptors’ affinity, selectivity, and agonist/antagonist activity greatly varied upon modifications to backbone geometry and the 3D display of pharmacophores. Methods: We utilized NMR, molecular dynamics, and molecular docking to analyze 3D structures and pharmacodynamic properties of selected representative cyclopeptide analogues of 1. Results: The simulations support that, despite its contradictory functional activity in vitro and in vivo, 1 can bind to the active conformation of receptors in an agonist-like fashion. In general, Trp appeared to be the fundamental pharmacophore in the ligand–receptor complexes. In particular, agonists showed a direct interaction between the indole ring and the carboxylate of the conserved Asp(3:32). Conclusions: These studies support a distinctive pharmacodynamic model for this class of compounds, potentially useful for the design of opioid compounds with novel binding/activity profiles and improved therapeutic effects. Full article

Background/Objectives: The use of the drug delivery system is notable for the systemic improvement of low orally bioavailable compounds, such as the bioactive phenolic acid, syringic acid. Innovative techniques are employed to enhance the performance of certain drug delivery systems. In connection with our previously reported journal with the use of MIL-100(Fe) as a drug carrier for syringic acid, this study utilized a mixed-linker synthesis of syringic acid and trimesic acid and characterized the properties in comparison with the unmodified MIL-100(Fe) through a solid solution approach. Methods: Modified MIL-100(Fe) was synthesized by substituting different molar concentrations of syringic acid for trimesic acid through de novo synthesis. Simple impregnation of syringic acid was carried out at 12, 24, 36, and 48 h and at 1:1 and 1:2 molar ratios of MIL-100(Fe) to syringic acid. Characterization was performed via PXRD, FTIR, BET, SEM, and DLS. In vivo studies included acute oral toxicity testing (OECD 425) and bioavailability assessment in Sprague Dawley rats. Results: The optimized amount of syringic acid to be substituted for trimesic acid is 0.10 mmol, as confirmed by the value of the PXRD. Optimized drug loading of 66.85 ± 0.004% was achieved using a 1:2 ratio of syringic acid to MIL-100(Fe)-10% over 36 h. Structural modifications were confirmed via FTIR, specifically through shifts at 1239.2 cm⁻¹, while TGA demonstrated thermal stability up to approximately 350 °C. Morphological analysis by SEM showed octahedral particles (210.70 ± 1.23 nm), and a decrease in BET surface area post-loading verified successful encapsulation. While in vitro release was media-dependent, toxicity studies at 2000 mg/kg showed no adverse effects; notably, SGOT and SGPT levels decreased, though BUN and creatinine levels rose. Compared to pure oral syringic acid, the SYA@MIL-100(Fe)-10% formulation demonstrated a 5.09-fold increase in relative bioavailability. Furthermore, it outperformed intraperitoneal administration of the drug by 1.65-fold. Conclusions: Modification of MIL-100(Fe) by incorporating syringic acid into the framework as a substituted organic linker indicates that SYA@MIL-100(Fe)-10% is a safe and effective delivery system for syringic acid, enhancing oral bioavailability. To the best of our knowledge, this is the first study to investigate the mixed-linker synthesis of MIL-100(Fe) by utilizing syringic acid as a structural co-ligand, rather than solely as an encapsulated guest. While MIL-100(Fe) has been extensively employed as a carrier for various therapeutics, this research uniquely integrates the active agent into the framework lattice itself to modulate porosity and loading capacity, subsequently evaluating its systemic performance in an in vivo model. Full article

Mass spectrometry-based analysis of post-translational modifications (PTMs) is a key strategy for characterizing protein regulation and identifying disease-associated targets, with endogenous PTMs serving as biomarkers for disease diagnosis and therapeutic response. More recently, chemical proteomic strategies have adapted PTM-focused workflows to measure engagement of covalent and photoactivatable small-molecule probes, expanding the scope of ligand discovery for these disease-associated targets. This review provides an overview of mass spectrometry-based PTM analysis workflows, including LC–MS/MS acquisition and post-acquisition data processing, with an emphasis on how modification-specific physicochemical properties influence PTM detection and identification. Common analytical challenges that limit PTM identification, including variable MS/MS fragmentation behavior and modification site localization, are discussed using modifications such as phosphorylation and photoaffinity labeling probe adducts as representative examples. Recent advances in acquisition strategies and computational tools that improve spectral quality and confidence in PTM assignment are also summarized. Additionally, approaches for the analytical validation of modification events, such as metabolic labeling strategies, are described. Together, this review outlines key considerations, capabilities, and limitations of MS-based PTM profiling and provides a framework for interpreting PTM datasets to support their effective integration into downstream biochemical and disease target validation studies. Full article

Epigallocatechin gallate (EGCG) represents the key phenolic compound in green tea, which has been verified to possess various biological effects but suffers from low stability and poor bioavailability. To address these issues, EGCG-loaded nanoliposomes (ELs) were screened and prepared using an ethanol injection–calcium acetate gradient (EtOH-CAG) method. An encapsulation efficiency of 94.61% was achieved, involving a particle size of 118.6 nm and a polydispersity index (PDI) of 0.23. Via layer-by-layer assembly, nanoliposomes modified with either ε-polylysine (ε-PL) monolayer (ELP) or ε-polylysine/sodium alginate (SA) bilayer (ELPA) exhibited substantially improved stability. Moreover, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and thermal analysis confirmed the effective loading of EGCG and the successful decoration of ε-PL and SA. Molecular docking analyses of dual ligands further characterized the surface modification mechanism, which was primarily mediated by hydrogen bonding and electrostatic interactions. ELPA maintained robust stability under conditions including 200 mM salt concentration, a pH range of 4–10, temperatures up to 55 °C, and a 25-day storage duration. The modified systems showed considerably enhanced cellular uptake without causing cytotoxicity. Collectively, the developed ε-PL/SA bilayer nanoliposomes offer an eco-friendly, efficient strategy to enhance EGCG stability and in vitro bioavailability in functional food applications. Full article

Glioblastoma multiforme (GBM) is the most lethal primary brain tumor in adults. Emerging evidence endorses that gut dysbiosis contributes to GBM progression through the gut–brain axis (GBA), promoting inflammation and therapeutic resistance via abnormal short-chain fatty acid production and cytokine dysregulation. Exosomes, naturally occurring nanovesicles (30–150 nm), offer promising therapeutic potential due to their blood–brain barrier permeability, biocompatibility, and versatile cargo capacity. This review examines exosome engineering strategies for dual targeting: inhibiting alterations in gut microbiome and inducing regulated cell death mechanisms such as apoptosis and ferroptosis in GBM. We describe exosome engineering with detailed focus on cargo loading approaches (e.g., genetic modification, electroporation, and sonication), exosome surface functionalization with specific ligands (e.g., antibodies), and exosome biogenesis pathway manipulation. Engineered exosomes can deliver anti-inflammatory agents and gut microbiome modulators to restore GBA homeostasis while simultaneously transporting tumor-suppressive non-coding RNAs (e.g., miRNAs, siRNAs) and therapeutic agents to induce apoptosis by overcoming temozolomide resistance, and trigger ferroptosis-inducing components in GBM stem cells. Preclinical studies make obvious that this dual-targeting approach ought to enhance therapeutic efficacy by creating systemic immunity and eliminating tumor cells. However, clinical translation brings forth challenges, such as manufacturing, targeting specificity, and standardized quality control, and warrants further study. Full article

Osteoarthritis is the most common musculoskeletal disorder. It primarily affects people in their mid-40s and older. As the disease progresses, degenerative changes occur in the synovial membrane, subchondral bone, and cartilage. Ultimately, the entire joint and its surrounding tissues become structurally and functionally impaired. Several sets of biochemical markers have been proposed to enable timely diagnosis and anticipate disease progression. However, only a few of these markers are routinely used to evaluate disease activity in subgroups. We conducted a cross-sectional, single-center cohort study of 72 patients with knee osteoarthritis. Diagnoses were established based on clinical data and radiological findings. We examined two Wnt/β-catenin signaling inhibitors, serum DKK-1 and sclerostin, and two bone/cartilage metabolic regulatory factors, RANKL and OPG, correlating these with disease activity and pain scores (WOMAC, VAS, and KOFUS), radiographic stage, inflammatory molecules and indices, and bone mineral density. DKK-1 levels were higher in the intensive pain group (VAS > 5) and positively correlated with the KOFUS throughout the study. This correlation was stronger in individuals with a BMI < 30. Serum DKK-1 levels were higher in patients with lower bone mineral density. No significant modifications in SOST, RANKL, or OPG levels were found in any of the above settings. In our patient cohort with mild-to-moderate knee osteoarthritis (OA), sclerostin, osteoprotegerin (OPG), and receptor activator of nuclear factor kappa-B ligand (RANKL) were not related to pain or disease activity. In contrast, DKK-1 was an indicator of pain and low-grade flare-ups. Furthermore, DKK-1 was associated with the KOFUS and impaired bone turnover in non-obese subgroups. Confirming these relationships in larger groups of patients would contribute to more efficient use of DKK-1 in disease stratification algorithms. Full article