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Plasmoelectronic-Based Ultrasensitive Assay of Tumor Suppressor microRNAs Directly in Patient Plasma: Design of Highly Specific Early Cancer Diagnostic Technology
摘要： It is becoming understood that microRNAs hold great promise for non-invasive liquid biopsies for screening for different types of cancer, but current state-of-the-art RT-PCR and microarray techniques have sensitivity limitations that currently restrict their use. Herein, we report a new transduction mechanism involving delocalization of photoexcited conduction electrons wavefunction of gold triangular nanoprism (Au TNP) in the presence of -ssDNA/microRNA duplexes. This plasmoelectronic effect increases the electronic dimension of Au TNPs and substantially affects their localized surface plasmon resonance (LSPR) properties that together allow us to achieve a sensitivity for microRNA assay as low as 140 zeptomolar concentrations for our nanoplasmonic sensors. We show that the position of a single base-pair mismatch in the -ssDNA/microRNA duplex dramatically alters the LSPR properties and detection sensitivity. The unprecedentedly high sensitivity of nanoplasmonic sensors has allowed us to assay four different microRNAs (microRNA-10b, -182, -143 and -145) from bladder cancer patient plasma (50 μL/sample). For the first time, we demonstrate the utility of a label-free, nanoplasmonic sensor in quantification of tumor suppressor microRNAs - the level of tumor suppressor microRNAs goes down in cancer patient as compared to normal healthy individuals - in metastatic and non-metastatic bladder cancer patient plasma. Our statistical analysis of patient samples unequivocally suggests that the tumor suppressor microRNAs are more specific biomarkers (p-value of <0.0001) than oncogenic microRNAs for differentiation between metastatic and non-metastatic bladder cancer, and non-metastatic cancer from healthy individuals. This work demonstrating the electron wavefunctions delocalization dependent ultrasensitive LSPR properties of noble metal nanoparticles has a great potential for fabrication of miniaturized and extremely powerful sensors to investigate microRNA properties in other cancers (for example breast, lung, and pancreatic) through liquid biopsy.
关键词： nanoplasmonic sensors,ultrasensitive detection,microRNAs,LSPR,liquid biopsy,bladder cancer,plasmoelectronic effect
更新于2025-09-23 15:22:29
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Data on characterization and validation of assays for ultrasensitive quantitative detection of small molecules: Determination of free thyroxine with magnetic and interferometric methods
摘要： The presented data refer to optimization and quantitative characterization of a rapid lateral flow assay based on high-affinity bifunctional ligand and magnetic nanolabels, which was developed for detection of small molecules of thyroid hormones. The results were obtained by including the magnetic particle quantification method, spectral-correlation interferometry and spectral-phase interferometry, dynamic light scattering, enzyme linked immunosorbent assay. The long-term stability of "antibody – magnetic nanoparticle" conjugates is shown. The assay specificity is confirmed, and verification of successful combination of magnetic particles and antibodies is demonstrated. The kinetic and equilibrium dissociation constants are determined for interactions between thyroxine and monoclonal antibodies. The obtained data could be used for design of other platforms for detection of small molecules.
关键词： ELISA,Lateral flow assay,Small molecules,Ultrasensitive detection,Free thyroxine,Interferometry,Magnetic nanolabels,Dynamic light scattering
更新于2025-09-23 15:22:29
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Ultrasensitive detection of nonlabelled bovine serum albumin using photothermal optical phase shift detection with UV excitation
摘要： Ultrasensitive detection of nonlabelled bovine serum albumin is performed in micro/nano?uidic chips using a photothermal optical phase shift (POPS) detection system. Currently, micro- and nano?uidics allow the analysis of various single cells, and their targets of interest are shifting from nucleic acids to proteins. Previously, our group developed photothermal detection techniques for the sensitive detection of non?uorescent molecules. For example, we developed a thermal lens microscope (TLM) with ultrahigh sensitivity at the single-molecule level and a POPS detector that is applicable to nanochannels smaller than the wavelength of light. The POPS detector also realized the detection of nonlabelled proteins in nanochannels, although its detection sensitivity is less than that of the TLM in microchannels due to insu?cient background light reduction. To overcome this problem, we developed a new POPS detector using relay optics for further reduction of the background light. In addition, heat transfer from the sample solution to the nanochannel wall was thoroughly investigated to achieve ultrahigh sensitivity. The limit of detection (LOD) obtained with the new POPS detector is 30 molecules in 1.0 fL. Considering this LOD, the performance of the new POPS detector is comparable with that of the TLM. Owing to the applicability of the POPS detector for sensitive detection even in nanochannels or single-μm channels, which cannot be realized with the TLM, combinations of the POPS detector and separation techniques employing unique nanochannel properties will contribute to advances in single-cell proteomics in the future.
关键词： Ultrasensitive detection,micro/nano?uidic chips,single-cell proteomics,photothermal optical phase shift,bovine serum albumin
更新于2025-09-23 15:19:57
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One-step scalable fluorescent microgel bioassay for the ultrasensitive detection of endogenous viral miR-US4-5p
摘要： Human cytomegalovirus (hCMV) infection is the leading cause of birth defects in newborns and death in immunosuppressed people. Traditional techniques require time-consuming and costly analyses, and sometimes result in false positive results; thus, a rapid and accurate detection for hCMV infection is necessary. Recently, hcmv-miR-US4-5p was selected as the biomarker for cytomegalovirus diagnosis and follow-up. Herein, we propose a bioassay based on microgels endowed with optical fluorescent oligonucleotide probes for the detection of circulating endogenous hcmv-microRNAs. In particular, a double strand probe, based on the fluorescence recovery after target capture, was conjugated on microgels and the probe density was opportunely optimised. Then, the microgels were directly mixed with the sample. The fluorescence read-out was measured as a function of target concentration at a fixed number of microgels per tube. As a bead-based assay, the performances of optical detection in terms of dynamic working range and limit of detection could be finely tuned by tuning the number of microgels per tube. The limit of detection of the assay could be tuned in the range from 39.1 fM to 156 aM by changing the microgel concentration from 50 μg mL?1 to 0.5 μg mL?1, respectively. The assay results specific for the selected target were stable over a one-year time span and they were not affected by the presence of human serum. Therefore, this bioassay based on microgels might represent a flexible platform that should be able to predict, identify and follow-up several diseases by monitoring freely circulating oligonucleotides in body fluids.
关键词： hcmv-miR-US4-5p,fluorescence recovery,toehold displacement,microgel bioassay,ultrasensitive detection
更新于2025-09-19 17:15:36
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Electro-plasmonic nanoantenna: A nonfluorescent optical probe for ultrasensitive label-free detection of electrophysiological signals
摘要： Harnessing the unprecedented spatiotemporal resolution capability of light to detect electrophysiological signals has been the goal of scientists for nearly 50 years. Yet, progress toward that goal remains elusive due to lack of electro-optic translators that can efficiently convert electrical activity to high photon count optical signals. Here, we introduce an ultrasensitive and extremely bright nanoscale electric-field probe overcoming the low photon count limitations of existing optical field reporters. Our electro-plasmonic nanoantennas with drastically enhanced cross sections (~104 nm2 compared to typical values of ~10?2 nm2 for voltage-sensitive fluorescence dyes and ~1 nm2 for quantum dots) offer reliable detection of local electric-field dynamics with remarkably high sensitivities and signal–to–shot noise ratios (~60 to 220) from diffraction-limited spots. In our electro-optics experiments, we demonstrate high-temporal resolution electric-field measurements at kilohertz frequencies and achieved label-free optical recording of network-level electrogenic activity of cardiomyocyte cells with low-intensity light (11 mW/mm2).
关键词： label-free,electrophysiological signals,ultrasensitive detection,optical probe,electro-plasmonic nanoantenna
更新于2025-09-19 17:13:59
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a??Burning Lampa??-like Robust Molecular Enrichment for Ultrasensitive Plasmonic Nanosensors
摘要： Enriching and locating target analytes into specific “hot spot” are vital for ultrasensitive molecular identification and detection using plasmonic-based techniques. Inspired by mass transportation in lamp wicks, we develop an effective enrichment strategy for highly diluted analytes, in which analytes and Au nanoparticles are transported via solution microflow under the capillarity driving force of glass fiber papers to a heated region. After evaporation, a large volume of solution contained analytes and Au nanoparticles are condensed into a very limited area, and thus, analyte molecules are effectively enriched and located into SERS hot spots. Using this enrichment strategy, the sensitivity and detection limits of SERS are remarkably improved. Detection levels of crystal violet and anthracene are down to 10-16 M and 10-10 M, respectively. This enrichment strategy is very robust and easy to implement, and it can potentially be exploited in various plasmonic-based molecular detection and identification techniques.
关键词： enrichment,ultrasensitive detection,heating evaporation,capillary force,surface enhanced Raman scattering
更新于2025-09-19 17:13:59
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DNA Nanofirecrackers Assembled through Hybridization Chain Reaction for Ultrasensitive SERS Immunoassay of Prostate Specific Antigen
摘要： Isothermal nucleic acid amplification technology has widely adopted for analytical chemistry with the purpose for sensitivity improvement. Herein we present an ultrasensitive concatenated hybridization chain reaction (C-HCR) based surface-enhanced Raman scattering (SERS) immunoassay by forming antibody-antigen-aptamer heterosandwich structures with the model analyte of total prostate specific antigens (tPSA). In the C-HCR, two HCRs, one proceeds with two hairpins, and the other with four biotin-modified hairpins, are coupled, making the formation of DNA nanofirecrackers with the lengths longer than 200 nm and more than four hundred million of binding site of streptavidin modified enzymes. This type of DNA nanofirecrackers through the aptamer encoded linker strand to form heterosandwich structures could provide a general signal application platform such as enzyme catalysis with high amplification efficiency. As a proof of concept, Au@Ag core-shell nanostructures based SERS immunoassay with excellent signal amplification has been developed by employing the streptavidin modified alkaline phosphatase (SA-ALP) through its catalysis of 2-phospho-L-ascorbic acid trisodium salt (AAP) to form Au@Ag core-shell nanostructures via the formation of ascorbic acid (AA) to reduce AgNO3 and deposition of silver element on gold nanorods (AuNRs). The newly developed method has a detection limit as low as 0.94 fg/mL, and has successfully achieved the detection of serum samples from clinical patients, which was consistent with the clinical test results, showing that this C-HCR strategy to form DNA nanofirecrackers has great potential in clinical applications.
关键词： SERS immunoassay,Hybridization Chain Reaction,Prostate Specific Antigen,Ultrasensitive detection,DNA nanofirecrackers
更新于2025-09-19 17:13:59
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An enzyme-free FRET nanoprobe for ultrasensitive ketamine detection based on ATP-fueled target recycling
摘要： Ketamine is a commonly abused drug due to its stimulant, dissociative and hallucinogenic effects. An overdose of ketamine has been found to cause a variety of side effects. Therefore, the identification and quantification of ketamine are of significant importance for clinical purposes and drug seizing. However, conventional methods for ketamine detection possess some disadvantages such as sophisticated procedures, expensive instruments and low sensitivity. Herein, we develop a novel fluorescent nanoprobe for ultrasensitive ketamine detection with signal amplification based on Adenosine Triphosphate (ATP)-fueled target recycling and FRET (fluorescence resonance energy transfer) occurring between the FAM (Fluorescein, tagged with Y-shape DNA) and AuNPs. Based on the combination of FRET and signals circle amplification, the gold nanospheres functionalized with Y-motif DNA (Y@AuNPs) nanoprobe was utilized for effective ketamine detection with the limit of detection (LOD) down to 3 pg mL?1, which was lower than previously reported. Furthermore, the high sensitivity of Y@AuNPs facilitated quantitative analysis in biological media and practical samples.
关键词： Ultrasensitive detection,Ketamine,FRET,ATP-fueled target recycling,Fluorescent nanoprobe
更新于2025-09-16 10:30:52
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4-Mercaptobenzoic Acid Labeled Gold-Silver-Alloy-Embedded Silica Nanoparticles as an Internal Standard Containing Nanostructures for Sensitive Quantitative Thiram Detection
摘要： In this study, (4-mercaptobenzoic acid labeled SiO2@Au@4-MBA@Ag gold-silver-alloy-embedded silica nanoparticles) nanomaterials were investigated for the detection of thiram, a pesticide. First, the presence of Au@4-MBA@Ag alloys on the surface of SiO2 was confirmed by the broad bands of ultraviolet-visible spectra in the range of 320–800 nm. The effect of the 4-MBA (4-mercaptobenzoic acid) concentration on the Ag shell deposition and its intrinsic SERS (surface-enhanced Raman scattering) signal was also studied. Ag shells were well coated on SiO2@Au@4-MBA in the range of 1–1000 μM. The SERS intensity of thiram-incubated SiO2@Au@4-MBA@Ag achieved the highest value by incubation with 500 μL thiram for 30 min, and SERS was measured at 200 μg/mL SiO2@Au@4-MBA@Ag. Finally, the SERS intensity of thiram at 560 cm?1 increased proportionally with the increase in thiram concentration in the range of 240–2400 ppb, with a limit of detection (LOD) of 72 ppb.
关键词： gold–silver-alloy-embedded silica nanoparticles,internal standard,thiram,ultrasensitive detection
更新于2025-09-16 10:30:52
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Simply synthesized nitrogen-doped graphene quantum dot (NGQD)-modified electrode for the ultrasensitive photoelectrochemical detection of dopamine
摘要： Recently, nitrogen-doped graphene quantum dots (NGQDs), as a new type of quantum semiconductor and photoelectrochemical material, are promising candidates in photoelectric sensing, water splitting, and biological imaging and have various potential application prospects. In this work, NGQDs were prepared by a simple calcination method, and then a photoelectrochemical sensing platform based on the NGQDs electrode with superior photoelectrochemical activity was designed and fabricated for the detection of dopamine (DA). Benefitting from the quantum effect and size effect, NGQDs displayed an enhanced photocurrent effective within ultra-low detection limit (0.03 μm), wide detection range (0.03–450 and 450–9680 μm), and high sensitivity in detecting DA with the assistance of ultraviolet light irradiation. The NGQDs electrode also showed continuous and stable photocurrent densities after long-term experiment, indicating the excellent durability of NGQDs for DA detection.
关键词： ultrasensitive detection,NGQDs,photoelectrochemistry,dopamine
更新于2025-09-11 14:15:04