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At least 19 recordsLinked to original sources
PubMed1992

Immobilization chemistries suitable for use in the BIAcore surface plasmon resonance detector.

Surface plasmon resonance detectors, such as the BIAcore instrument produced by Pharmacia, show promise for the detection and quantitation of macromolecular interactions in a label-free mode. Such detectors rely on the covalent immobilization of one of the interacting species onto the sensing surface. To date, the only published chemistry for this purpose is reaction of primary amino-containing ligands with an N-hydroxysuccinimide (NHS) ester-activated surface. In an effort to increase the versatility of the BIAcore with respect to immobilizing ligands, we undertook an investigation of activation chemistries compatible with this system. Using readily available reagents, we demonstrated that the carboxylated dextran-coated sensing surface could be easily converted to functions other than NHS-esters, including amine-activated, hydrazine-activated, and sulfhydryl-activated surfaces. In addition, use was made of the streptavidin/biotin interaction to probe chemical modifications of the sensing surface, by employing specifically modified biotin derivatives.

Avidin↗
PubMed1992

Detection of receptor-ligand interactions using surface plasmon resonance: model studies employing the HIV-1 gp120/CD4 interaction.

Surface plasmon resonance (SPR), a label-free, real time optical detection principle, has been investigated for its potential to detect and quantitate macromolecular ligand-ligate interactions. As model systems, the interactions of the HIV-1 envelope glycoprotein, gp120, and the monoclonal antibody L-71, with a soluble form of the T-cell receptor CD4 (sCD4), were investigated. In an effort to demonstrate potential analytical applications of this technology, operational characteristics of the SPR instrumentation (BIAcore, Pharmacia) including stability of the sensing surface and reproducibility in the measurement of such macromolecular interactions were investigated. In addition, the ability to detect and quantitate sCD4 directly from unfractionated cell culture supernatants, such as Streptomyces lividans, was investigated. The results demonstrate that SPR has potential in quantitating macromolecular interactions in both purified and crude samples and that the reproducibility in, and sensitivity of, such determinations is comparable to other techniques.

Antibodies, Monoclonal↗
PubMed1992

Biospecific interaction analysis using surface plasmon resonance detection applied to kinetic, binding site and concentration analysis.

A system for real-time biospecific interaction analysis using biosensor technology based on the optical phenomenon surface plasmon resonance is described. The biospecific interface is a sensor chip covered with a hydrogel matrix. One component of the interaction to be studied is immobilized covalently to the hydrogel and other interactants are passed over the chip in solution. The mass change at the sensor surface, reflecting the progress of the interaction studied, is monitored in real time. The technique, which does not require molecular labels for detection, can measure mass changes down to 10 pg/mm2. Repeated analyses can be performed on the same sensor chip. Applications shown include kinetic measurements, binding site analysis and concentration determination.

Antibodies, Monoclonal↗
PubMed2024

Comparative Studies on Bulky DNA Damage Binding by Nucleotide Excision Repair Proteins Using Surface Plasmon Resonance, Differential Scanning Fluorometry, and DNase I Footprinting.

Nucleotide excision repair is a crucial cellular mechanism that ensures genomic stability, thereby preventing mutations that can lead to cancer. The human XPC and its yeast ortholog Rad4 protein complexes are central to this process and were the focus of the study. We used surface plasmon resonance and differential scanning fluorimetry to study the binding characteristics of XPC and Rad4 when bound to the bulky cluster di-FAAF-containing 55-mer duplex DNA. Our findings revealed that XPC binds 10 times more significant affinity to control and di-FAAF-modified DNA than Rad4 with greater protein-DNA interactions. Differential scanning fluorimetry indicates that Rad4 causes comparatively more significant conformational changes upon complexation with the damaged DNA. We conducted DNase I footprinting of the Rad4/DNA complex for the first time by determining the regions protected from DNase I digestion. The DNA at the lesion is entirely resistant to digestion by DNase I in the absence of Rad4 several nucleotides to the 3'-side of the first FAAF lesion. The lack of DNase I cleavage at the lesions did not change upon adding Rad4. However, in the presence of Rad4, a footprint is observed on the 7-nucleotide region (5'-TGGTGAT-3') of the complementary strand to the 3' side of the lesion.

Surface Plasmon Resonance↗
PubMed1992

A surface plasmon resonance immunosensor based on the streptavidin-biotin complex.

It is shown that a streptavidin monolayer immobilized onto an evaporated gold film with biotin forms the basis of a highly specific sensing element. As an example, we show that by immobilizing the biotinylated antibody sex hormone binding globulin (alpha-SHBG) to the bound streptavidin monolayer a specific sensor for the antigen SHBG is readily fabricated. The interaction between immobilized antibody and corresponding antigen is monitored by surface plasmon resonance spectroscopy and is shown to follow a classic Langmuir isotherm. Detection of SHBG at nanomolar concentrations is demonstrated.

Antigens↗
PubMed1992

Interaction between viruses and monoclonal antibodies studied by surface plasmon resonance.

An automated biosensor system designed for measuring molecular interactions in real time and without any labelling of the reactants has been used to study the interaction of two animal viruses (vaccinia virus and poliovirus) and two plant viruses (cowpea mosaic virus and tobacco mosaic virus) with monoclonal antibodies. Using monoclonal antibodies specific for different conformational states of viral protein, it was found that the virus particles retained their conformational integrity when immobilized on the dextran matrix present on the sensor chip. Compared to conventional solid phase immunoassays, in which immobilized proteins are usually partly denatured, the biosensor system presents several advantages for studying virus-antibody interaction.

Antibodies, Monoclonal↗
PubMed2026

Schisantherin B mitigates cisplatin-induced ototoxicity by modulating the CNPY2-PERK/CHOP signaling axis.

Irreversible cisplatin-induced hearing loss (CIHL) is a refractory chemotherapy-related adverse effect with limited clinical treatments. Schisantherin B (STB), a lignan isolated from Schisandra chinensis, is widely recognized for its neuroprotective properties, while its role in auditory injury remains unclear. Herein, we found that STB alleviated cisplatin-induced ototoxicity in House Ear Institute Organ of Corti 1 (HEI-OC1) cells and guinea pig models, protecting cochlear hair cells, synaptic ribbons and spiral ganglion neurons, and partially restoring auditory brainstem response (ABR) thresholds. Furthermore, combined drug affinity responsive target stability (DARTS) assay, the cellular thermal shift assay (CETSA), and the surface plasmon resonance (SPR) assay, we confirmed STB directly binds to the canopy FGF signaling regulator 2 (CNPY2), a key initiator of endoplasmic reticulum (ER) stress. Notably, consistent dual in vitro and in vivo validation confirmed that STB exerts no regulatory effect on CNPY2 protein abundance, yet suppressed the downstream Protein kinase R-like endoplasmic reticulum kinase / C/EBP homologous protein (PERK/CHOP) signaling cascade and ER stress-mediated apoptosis. Moreover, molecular docking and co-immunoprecipitation (co-IP) validated the physical binding of STB to CNPY2 and the endogenous interaction between CNPY2 and PERK. Additionally, CNPY2 overexpression and shRNA knockdown further verified this functional relationship. Integrated proteomic and transcriptomic analyses showed STB partially reversed cisplatin-triggered inflammation and excessive ER stress. Collectively, our results suggest STB may serve as a potential otoprotective agent. The CNPY2-PERK/CHOP axis is closely linked to cisplatin-induced cochlear damage and offers a feasible target for intervention against CIHL. Abbreviations: CIHL, cisplatin-induced hearing loss; STB, Schisantherin B; HEI-OC1, house ear institute organ of corti 1; ABR, auditory brainstem response; DARTS, drug affinity responsive target stability; CETSA, cellular thermal shift assay; SPR, surface plasmon resonance; CNPY2, canopy FGF signaling regulator 2; ER, endoplasmic reticulum; PERK, protein kinase R-like endoplasmic reticulum kinase; CHOP, C/EBP homologous protein; co-IP, co-immunoprecipitation; STA, Schisantherin A; STC, Schisantherin C; dB SPL, decibels sound pressure level; EDTA, ethylenediaminetetraacetic acid; dB SPL, decibels sound pressure level; SGN, spiral ganglion neuron; IHCs, inner hair cells; OHCs, outer hair cells; CCK-8, Cell Counting Kit-8; OD, optical density; ODb, blank sample, ODc, control sample; NC, negative control; PVDF, polyvinylidene difluoride; RT, room temperature; LC-MS/MS, liquid chromatography tandem mass spectrometry; MS, mass spectrometry; DMSO, dimethyl sulfoxide; KDs, equilibrium dissociation constants; SP, standard precision; SEM, standard error of the mean; HSD, honestly significant difference; Ctrl, control group; CV, cell viability; Kd, dissociation rate constant; Ka, association rate constant; STS, sodium thiosulfate; UPR, unfolded protein response; BLB, blood-labyrinth barrier.

Apoptosis↗
PubMed2026

PRDX1 as a novel urinary biomarker for bladder cancer: Development of an integrated fiber optic sensing platform.

In this study, integrated proteomic and transcriptomic analyses identified peroxiredoxin 1 (PRDX1) as a novel urinary biomarker for bladder cancer (BC). PRDX1 was significantly upregulated in BC tissues and was associated with poorer overall survival. In vitro experiments further demonstrated that PRDX1 promotes malignant phenotypes of BC cells, including proliferation, migration, and invasion. Silencing PRDX1 in BC cells significantly reduced the invasiveness and proliferation ability.To address the clinical need for rapid and non-invasive detection, we developed an innovative optical fiber biosensor based on surface plasmon resonance (SPR) technology for the quantitative detection of urinary PRDX1. The biosensor exhibited excellent analytical performance, including high sensitivity (limit of detection: 0.06 ng/mL), a wide linear range (0-25 ng/mL), rapid response (∼14 s), as well as good stability and selectivity. In clinical validation involving 97 BC patients and 30 healthy controls, the biosensor demonstrated outstanding diagnostic performance, with an area under the receiver operating characteristic curve (AUC) of 0.91 and an overall diagnostic accuracy of 86.6%, outperforming conventional enzyme-linked immunosorbent assay (ELISA). Collectively, this study not only identifies PRDX1 as a promising biomarker for non-invasive diagnosis and prognostic evaluation of BC, but also establishes an efficient SPR-based optical fiber sensing platform, providing new insights into both clinical detection and the functional role of PRDX1 in BC progression.

Humans↗
PubMed1992

Real time analysis of antibody-antigen reaction kinetics.

Surface plasmon resonance, i.e. detection of changes in refractive index on a surface, was used in a biosensor to evaluate the dissociation/association rate and affinity constants of human monoclonal IgG and IgM antibodies and Fab fragments. The results showed that an observed difference in affinity constants between intact and fragmented IgG anti-tetanus antibody was related to approximately 10-fold differences in dissociation rate constants, since the association rate constants were in the same range, i.e. 2-3 x 10(5) (M-1 s-1). Affinity constants, as determined by conventional solid phase enzyme immunoassay, were substantially higher than the constants produced by the biosensor. Human monoclonal IgM anti-Tn alpha antibodies showed, furthermore, one order of magnitude higher association rate constants, as compared with the IgG antibodies, but since the dissociation rate constants were more than ten times higher, the resulting affinity constants of the anti-carbohydrate IgM antibodies were still somewhat lower than those of the IgG antibodies.

Antibodies, Monoclonal↗
PubMed2024

Adeno-Associated Virus Type 5 Infection via PDGFRα Is Associated With Interstitial Lung Disease in Systemic Sclerosis and Generates Composite Peptides and Epitopes Recognized by the Agonistic Immunoglobulins Present in Patients With Systemic Sclerosis.

OBJECTIVE: The etiopathogenesis of systemic sclerosis (SSc) is unknown. Platelet-derived growth factor receptors (PDGFRs) are overexpressed in patients with SSc. Because PDGFR&#x3b1; is targeted by the adeno-associated virus type 5 (AAV5), we investigated whether AAV5 forms a complex with PDGFR&#x3b1; exposing epitopes that may induce the immune responses to the virus-PDGFR&#x3b1; complex. METHODS: The binding of monomeric human PDGFR&#x3b1; to the AAV5 capsid was analyzed by in silico molecular docking, surface plasmon resonance (SPR), and genome editing of the PDGFR&#x3b1; locus. AAV5 was detected in SSc lungs by in situ hybridization, immunohistochemistry, confocal microscopy, and molecular analysis of bronchoalveolar lavage (BAL) fluid. Immune responses to AAV5 and PDGFR&#x3b1; were evaluated by SPR using SSc monoclonal anti-PDGFR&#x3b1; antibodies and immunoaffinity-purified anti-PDGFR&#x3b1; antibodies from sera of patients with SSc. RESULTS: AAV5 was detected in the BAL fluid of 41 of 66 patients with SSc with interstitial lung disease (62.1%) and in 17 of 66 controls (25.75%) (P <&#x2009;0.001). In SSc lungs, AAV5 localized&#x2009;in type II pneumocytes and in interstitial cells. A molecular complex formed of spatially contiguous epitopes of the AAV5 capsid and of PDGFR&#x3b1; was identified and characterized. In silico molecular docking analysis and binding to the agonistic anti-PDGFR&#x3b1; antibodies identified spatially contiguous epitopes derived from PDGFR&#x3b1; and AAV5 that interacted with SSc agonistic antibodies to PDGFR&#x3b1;. These peptides were also able to bind total IgG isolated from patients with SSc, not from healthy controls. CONCLUSION: These data link AVV5 with the immune reactivity to endogenous antigens in SSc and provide a novel element in the pathogenesis of SSc.

Humans↗
PubMed2026

Microalgae-Mediated Synthesis of Gold Nanoparticles from Indonesian Chlorella vulgaris InaCC M205 with Potential Anticancer Properties for Biomedical Application.

Sustainable nanomaterial synthesis has emerged as a critical strategy to reduce the environmental burden associated with conventional chemical synthesis method. Microalgae-derived biomolecules offer a promising platform for the green production of metal nanoparticles due to their rich bioactive compounds capable of acting as natural reducing and stabilizing agents. Here, we report the eco-friendly synthesis of gold nanoparticles (AuNPs) using extract of Indonesian microalga Chlorella vulgaris extract. To optimize the synthesis process, the effects of precursor-to-extract ratio, temperature, and incubation time were evaluated. Optimal synthesis of C5-AuNPs was obtained at 37&#x2009;&#xb0;C for 20&#x2009;h with precursor to extract ratio of 6:4, resulting in moderately stable C5-AuNPs characterized by a surface plasmon resonance (SPR) peak at 541&#x2009;nm. Furthermore, Fourier-transmission infra-red (FT-IR) analysis revealed the involvement of functional groups of C. vulgaris extract in the interaction with Au+ during the production of C5-AuNPs. Transmission electron microscopy (TEM) demonstrated the formation of uniformly spherical nanoparticles with an average diameter of approximately 8.8&#x2009;nm. Biological evaluation showed that the synthesized C5-AuNPs exerted pronounced dose-dependent cytotoxicity against MCF-7 breast cancer cells with an IC50 threshold of 21.17 ppm, while no toxicity appears in normal HEK293 cells. Mechanistically, the C5-AuNPs induced early apoptosis and inhibit cell-cycle progression at the stage of G0/G1. Collectively, these findings demonstrate that C. vulgaris-mediated AuNPs represent a promising preliminary in vitro findings for cancer therapy candidate.

Gold↗
PubMed2025

A genome-wide CRISPRi screen identifies homologous recombination pathway as potential target for broad-spectrum antibiotic adjuvants.

INTRODUCTION: The widespread misuse and overuse of antibiotics have driven the emergence of multidrug-resistant and pan drug-resistant bacteria, constituting a formidable global health threat. Antibiotic adjuvants that potentiate the efficacy of existing antibiotics represent a particularly promising avenue to address this challenge. METHODS: We performed a genome-wide CRISPR interference (CRISPRi) screening to identify potential targets for broad-spectrum antibiotic adjuvants, which highlighted the homologous recombination pathway as a promising candidate. To functionally validate this pathway, we employed three strategies to suppress the expression and function of recA, a key component of homologous recombination, including a CRISPRi system delivered via transconjugation, a RecX-derived peptide (RecX-20) fused to a cell-penetrating motif, and a small-molecule inhibitor cisplatin validated by surface plasmon resonance. RESULTS: Disruption of the homologous recombination pathway not only significantly increased bacterial susceptibility to multiple classes of antibiotics, including quinolones, &#x3b2;-lactams, aminoglycosides, and nitrofurantoin, but also reduced horizontal gene transfer of antibiotic resistance. In addition, recA deficiency resulted in a cascade of physiological disruptions, including membrane damage, efflux pump dysfunction, oxidative stress imbalance and metabolic disruption. All three recA-targeting strategies enhanced the antibacterial activity, with cisplatin exhibiting the most pronounced potentiating effect both in vitro and in vivo. CONCLUSIONS: This study reveals that the homologous recombination pathway, particularly RecA, is a viable target for the development of broad-spectrum antibiotic adjuvant. Our findings provide mechanistic insights and practical strategies to restore the effectiveness of existing antibiotics and address the growing threat of antimicrobial resistance.

Anti-Bacterial Agents↗
PubMed2026

Chemotactic sensing of extracellular antibiotic resistance genes enables their efficient removal by Stutzerimonas stutzeri.

The dissemination of antibiotic resistance genes (ARGs) in wastewater environments poses a severe threat to public health. Extracellular ARGs (eARGs) persist as free DNA fragments that are refractory to efficient removal by conventional physicochemical treatment technologies. Here, we isolated Stutzerimonas stutzeri CHY07 from municipal sewage and demonstrated that extracellular DNA fragments, including eARGs, can serve as chemoattractants for environmental bacteria. Through genomic mining, molecular docking, surface plasmon resonance (SPR), isothermal titration calorimetry (ITC) and protein-ligand interaction profiling, we identified the chemoreceptor Mcp16 as the primary sensor of extracellular DNA and revealed that it achieves sequence-independent recognition of the DNA phosphate backbone. We further established the endogenous pentapeptide VRSVR as a methylation substrate for CheR and constructed the engineered strain CHY07-2 (mcp16::VRSVR) using an SSB/CRISPR-Cas9 ribonucleoprotein (RNP) system. This strain exhibited significantly enhanced chemotactic responsiveness, achieving 72-h removal efficiencies of 96.56% and 91.60% for low- and high-molecular-weight eARGs in non-sterile WWTP secondary effluent; conversely, mcp16 deletion markedly attenuated both chemotaxis and removal, whereas in situ complementation restored them. These findings reveal a "chemotaxis-contact-removal" cascade - with a proposed self-reinforcing loop - in eARG-removing bacteria, providing both a theoretical framework and a technical paradigm for enhancing pollutant removal through targeted amplification of microbial chemotaxis.

Chemotaxis↗
PubMed2025

DNA Nanostructure Self-Assembly in an Aqueous Ionic Liquid Solution with Enhanced Stability and Target Binding Affinity.

DNA nanostructure-enabled functional constructs have shown potential to improve healthcare outcomes by offering advanced disease diagnostic and therapeutic strategies. Translating this potential of DNA nanostructure-based constructs to real life applications relies on maintaining and enhancing the structural integrity and functions of the surface-anchored moieties. In this study, we explored the possibility of utilizing choline dihydrogen phosphate (CDHP) solution, an aqueous solution of ionic liquid, to assemble DNA nanostructures of different sizes and complexities with enhanced biostability and ligand binding affinity. We show successful formation of the DNA nanostructures in aqueous CDHP solution using gel electrophoresis, atomic force microscopy (AFM), and circular dichroism (CD). Biostability assays reveal that the aqueous CDHP solution may provide passive protection to DNA nanostructures against DNase I and human serum for up to 48 h. We also demonstrate that this enhanced biostability arises both from the structural conformation imparted during CDHP-mediated folding and from the presence of free CDHP ions in the solution. Notably, removal of free ions reduced the passive protection effect, but did not eliminate it, indicating the contribution of both folding and surrounding free ions. Using flow cytometry and surface plasmon resonance assays, we show that the presence of aqueous CDHP solution can enhance the binding of aptamer-functionalized DNA nanostructures to specific receptors on acute myeloid leukemia (AML) cells. Our strategy of using ionic liquid solution for one-pot preparation with enhanced stability and functionality offers a robust, simpler and faster alternative for DNA nanostructure-based constructs.

Ionic Liquids↗