- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Fully Packaged Portable Thin Film Biosensor for the Direct Detection of Highly Pathogenic Viruses from On-Site Samples
摘要： The thin film transistor (TFT) is a promising biosensor system with great sensitivity, label-free detection, and a quick response time. However, even though the TFT sensor has such advantageous characteristics, the disadvantages hamper the TFT sensor's application in the clinical field. The TFT is susceptible to light, noise, vibration, and limited usage, and this significantly limits its on-site potential as a practical biosensor. Herein, we developed a fully packaged, portable TFT electrochemical biosensor into a chip form, providing both portability through minimizing the laboratory equipment size and multiple safe usages by protecting the semiconductor sensor. Additionally, a safe environment that serves as a miniature probe station minimizes the previously mentioned disadvantages, while providing the means to properly link the TFT biosensor with a portable analyzer. The biosensor was taken into a biosafety level 3 (BSL-3) laboratory setting to analyze highly pathogenic avian influenza virus (HPAIV) samples. This virus quickly accumulates within a host, and therefore, early stage detection is critical to deterring the further spread of the deadly disease to other areas. However, current on-site methods have poor limits of detection (105?106 EID50/mL), and because the virus has low concentration in its early stages, it cannot be detected easily. We have compared the sample measurements from our device with virus concentration data obtained from a RT-PCR (virus range: 100?104 EID50/mL) and have identified an increasing voltage signal which corresponds to increasing virus concentration.
关键词： avian influenza virus,label-free detection,portable biosensor,chip sensor,rapid detection
更新于2025-09-23 15:23:52
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Invisible-ink-assisted pattern and written surface-enhanced Raman scattering substrates for versatile chem/biosensing platforms
摘要： In recent years, highly sensitive surface-enhanced Raman scattering (SERS) integrated with flexible substrates has drawn increasing attention for label-free detection. In this study, an invisible ink-inspired process was developed for the fabrication of plasmonic Au-based SERS substrates through an on-site redox strategy. Tannic acid (TNA), a common green reagent, was used not only for fabricating various SERS absorbents through a confinement reduction of a Au-TNA complex, but also for supplying an amphiphilic inorganic–organic surface structure for outstanding SERS enhancement at micromolar to nanomolar concentrations for a wide range of compounds. In addition to label-free sensing, this TNA/Au-based SERS substrate provides a versatile analysis platform for studies of chemical and biological reactions. A combination of TNA ink with different metal ions allows for a reliable procedure for the synthesis of a bimetallic AuAg SERS substrate that further enhances the SERS intensity of analyte molecules and extends the lower limit of detection.
关键词： bimetallic AuAg SERS substrate,invisible ink,tannic acid,label-free detection,SERS,plasmonic Au-based SERS substrates,surface-enhanced Raman scattering
更新于2025-09-23 15:21:21
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Mechanisms of Fano-resonant biosensing: Mechanical loading of plasmonic oscillators
摘要： Distinctively narrow and asymmetric line shape Fano resonances arise due to resonant interactions of sub-radiant and super-radiant modes in plasmonic nanostructures and metamaterials. A number of recent experimental studies have shown unique opportunities provided by highly dispersive Fano resonances in biosensing applications. However, there is limited understanding of Fano resonant optical response to biomolecular accumulation. Here, we introduce a phenomenological model that can precisely describe the intricate nature of the Fano resonances in plasmonic nanohole arrays and provide unambiguous physical insights into biosensing experiments. Using rigorous electromagnetic simulations and experimental measurements as benchmarking tools, we show that the non-trivial contribution of molecular accumulation to Fano resonant plasmonic response can be incorporated as a mechanical loading effect in a coupled-oscillator model. Quite remarkably, our phenomenological approach captures the complex spectral response of the Fano resonance profile and asymmetric linewidth broadening upon molecular accumulation. Furthermore, in strong agreement with our experimental measurements, we show that our parameterized model has predictive power in fine tuning the Fano resonant extraordinary light transmission lineshape using structural design parameters without resorting to electromagnetic simulations. Our phenomenological model provides a general analytical method that can be adapted to understand biomolecular detection measurements in different plasmonic and metamaterial systems.
关键词： Biosensing,Extraordinary light transmission,Plasmonics,Plasmonic nanoholes,Fano resonances,Label-free detection
更新于2025-09-23 15:19:57
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Fungal In Situ Assembly Gives Novel Properties to CdS <sub/><i>x</i> </sub> Se <sub/> 1a?? <i>x</i> </sub> Quantum Dots for Sensitive Label-Free Detection of Chloramphenicol
摘要： Quantum dots (QDs) are attracting significant attention for the development of sensitive detection methods because of their unique optical properties. Biosynthetic QDs using organisms is a promising alternative route to chemical synthesis because it is a simple and eco-friendly process. Herein, we developed a straightforward and green system for the biological assembly of CdSxSe1?x QDs by Phomopsis sp. XP-8 within 6 h, a more efficient approach than those reported in other organisms. The QDs were shown to have a CdS0.75Se0.25@oligopeptide transporter structure, and the production process was shown to be strongly influenced by intracellular glutathione content. The QDs were monodispersed with a uniform spherical shape of 3.22 ± 0.07 nm in diameter. They exhibited good water solubility and excellent fluorescence properties. The QDs could be extracted and used directly as a sensitive chloramphenicol (CAP) probe via static fluorescence quenching in the linear range from 3.13 to 500 μg/L with a detection limit of 0.89 μg/L. The detection method was highly selective for CAP with minimal interference from other antibiotics and was used to successfully detect CAP in milk samples. Overall, this work has great significance for the development of a fast and simple QD synthesis system via biological assembly.
关键词： Phomopsis sp. XP-8,Chloramphenicol,CdSxSe1?x quantum dots,Biosynthesis,Label-free detection
更新于2025-09-23 15:19:57
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Principles for Sensitive and Robust Biomolecular Interaction Analysis: The Limits of Detection and Resolution of Diffraction-Limited Focal Molography
摘要： Label-free biosensors enable the monitoring of biomolecular interactions in real time, which is key to the analysis of the binding characteristics of biomolecules. While refractometric optical biosensors such as surface plasmon resonance (SPR) are sensitive and well-established, they are susceptible to any change of the refractive index in the sensing volume caused by minute variations in composition of the sample buffer, temperature drifts, and most importantly nonspecific binding to the sensor surface in complex fluids such as blood. The limitations arise because refractometric sensors measure the refractive index of the entire sensing volume. Conversely, diffractometric biosensors–for example, focal molography–only detect the diffracted light from a coherent assembly of analyte molecules. Thus any refractive index distribution that is noncoherent with respect to this molecular assembly does not add to the coherent signal. This makes diffractometric biosensors inherently robust and enables sensitive measurements without reference channels or temperature stabilization. The coherent assembly is generated by selective binding of the analyte molecules to a synthetic binding pattern–the mologram. Focal molography has been introduced theoretically [C. Fattinger, Phys. Rev. X 4, 031024 (2014)] and verified experimentally [V. Gatterdam, A. Frutiger, K.-P. Stengele, D. Heindl, T. Lübbes, J. V?r?s, and C. Fattinger, Nat. Nanotechnol. 12, 1089 (2017)] in previous papers. However, further understanding of the underlying physics and a diffraction-limited readout is needed to unveil its full potential. This paper introduces refined theoretical models, which can accurately quantify the amount of biological matter bound to the mologram from the diffracted intensity. In addition, it presents measurements of diffraction-limited molographic foci, i.e., Airy discs. These improvements enable us to demonstrate a resolution in real-time binding experiments comparable to the best SPR sensors without the need for temperature stabilization or drift correction and to detect low-molecular-weight compounds label free in an endpoint format. The presented experiments exemplify the robustness and sensitivity of the diffractometric sensor principle.
关键词： biomolecular interaction analysis,diffractometric biosensors,focal molography,diffraction-limited foci,robustness,label-free detection,sensitivity
更新于2025-09-19 17:15:36
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Protein-functionalized WO3 nanorods–based impedimetric platform for sensitive and label-free detection of a cardiac biomarker
摘要： We report the development of a sensitive and a label-free electrochemical immunosensing platform for the detection of cardiac biomarker troponin I (cTnI) using tungsten trioxide nanorods (WO3 NRs). The low-temperature hydrothermal technique was employed for the controlled synthesis of WO3 NRs. Thin films of 3-aminopropyltriethoxy saline (APTES)-functionalized WO3 NRs were deposited on indium tin oxide (ITO)-coated glass substrate (0.5 cm × 1 cm) using electrophoretic deposition technique. The covalent immobilization of cTnI antibody onto functionalized WO3 NRs electrode was accomplished using EDC-NHS [1-(3-(dimethylamino)-propyl)-3-ethylcarbodiimide hydrochloride and N-hydroxysulfosuccinimide] chemistry. The structural and morphological characterizations of WO3 NRs and functionalized WO3 NRs were studied using X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, and electrochemical techniques. The impedimetric response study of the proposed immunosensor demonstrates high sensitivity [6.81 KΩ·mL/(ng·cm2)] in a linear detection range of 0.01–10 ng/mL. The excellent selectivity, good reproducibility, and long-term stability of the proposed immunosensing platform indicate WO3 NRs as a suitable platform for the development of a point-of-care biosensing device for cardiac detection.
关键词： electrochemical impedance spectroscopy,tungsten trioxide nanorods,immunosensor,cardiac biomarker,label-free detection
更新于2025-09-19 17:15:36
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One-step hydrothermal synthesis of down/up-conversion luminescence F-doped carbon quantum dots for label-free detection of Fe3+
摘要： In this work, a kind of down/up-conversion luminescent F-doped carbon dots (F-CDs) with high fluorescence quantum yield was prepared by one-step hydrothermal treatment of perfluorooctanoic sulfonate (PFOS) and was used for the label-free detection of Fe3+. The obtained F-CDs have a uniform and monodispersed size at 4 nm, and show good properties such as down/up-conversion luminescence, good water-solubility, anti-photo-bleaching, salt tolerance, and high fluorescence quantum yield of about 35.2%. The down/up-conversion photoluminescence emissions both are independent on the excitation and both the emission peaks are at 447 nm, which indicates it is promising to be used as fluorescent whitening agent. Based on the quenching effect of iron ions, a simple, sensitive, low-cost and label-free fluorescent assay for iron ions has been developed with a liner range of 1–100 μM and a limit of detection (LOD) of 10 nM. Furthermore, the label-free nanoprobe has been successfully applied for the detection of Fe3+ in real samples.
关键词： Fe3+,Down/up-conversion,Carbon dots,F-doped,Label-free detection
更新于2025-09-12 10:27:22
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Label-free detection of folic acid using a sensitive fluorescent probe based on ovalbumin stabilized copper nanoclusters
摘要： In this work, ovalbumin (OVA) stabilized copper nanoclusters (OVA-Cu NCs) were prepared through a simple protein-stabilized synthetic method and applied for the sensitive determination of FA. Cu2+ ions were directly reduced to Cu (0) by a mild reducing agent, N2H4·H2O, at room temperature without any other complicated procedure such as adjusting pH and controlling the temperature of the reaction mixture. The as-prepared OVA-Cu NCs showed good chemical stability, wonderful water solubility and excellent biocompatibility. The OVA-Cu NCs were obtained with an average particle size of 2.0 nm and good dispersibility in aqueous solution. They also showed strong red emitting at 625 nm with a quantum yield of 3.95%. The OVA-Cu NCs were then applied for label-free detection of FA based on a static quenching mechanism. The linear calibration curve of detecting FA served from 0.5 μM -200 μM with the detection limit of 0.18 μM. In addition, the developed method was also successfully applied to determine the content of FA in tablet, spinach, orange juice and biological samples with quantitative spike recoveries from 96.9% to 100.9%. For these reasons, the developed OVA-Cu NCs-based fluorescent strategy can thus offer a convenient label-free biosensor platform for the detection of FA in biomedical applications.
关键词： label-free detection,folic acid,red emitting,copper nanoclusters
更新于2025-09-09 09:28:46
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Label-free bacteria quantification in blood plasma by a bioprinted microarray based interferometric point-of-care device
摘要： Existing clinical methods for bacteria detection lack in speed, sensitivity and importantly in Point-of-Care (PoC) applicability. Thus, finding ways to push the sensitivity of clinical PoC biosensing technologies is crucial. Aiming that, we here report a portable PoC device based on Lens-free Interferometric Microscopy (LIM). The device employs high performance nanoplasmonics and custom bioprinted microarrays and is capable of direct label-free bacteria (E. coli) quantification. With only one-step sample handling we offer a sample?to?data turnaround time of 40 minutes. Our technology features detection sensitivity of a single bacterial cell both in buffer and diluted blood plasma and is intrinsically limited by the number of cells present in the detection volume. When employed in a hospital setting, the device has enabled accurate categorization of sepsis patients (infectious SIRS) from control groups (healthy individuals and non-infectious SIRS patients) without false positives/negatives. User-friendly on-site bacterial clinical diagnosis can thus become a reality.
关键词： microarray,label-free detection,plasma samples,nanoplasmonics,sepsis,bacteria
更新于2025-09-09 09:28:46
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Nickel Nanowires Combined with Surface-Enhanced Raman Spectroscopy: Application in Label-Free Detection of Cytochrome c-Mediated Apoptosis
摘要： Intrinsic properties of nickel have enabled its wide applications as an effective catalyst. In this study, nickel nanowires (Ni NWs) as electron donors for oxidized cytochrome c (Cyt c) are investigated, which are NW diameter, temperature, and pH value-dependent. The reductive and magnetic properties facilitate the Ni NWs to rapidly and conveniently reduce Cyt c in complicated biological samples. Moreover, we find that the Ni NWs combined with resonance Raman spectroscopy have specificity towards Cyt c detection in real biological samples, which is successfully used to distinguish the redox state of the released Cyt c from isolated mitochondria in apoptotic Hela cells. Moreover, rapid label-free Cyt c quantification can be achieved by surface-enhanced Raman spectroscopy with a limit of detection range of 1 nM and long concentration linear (1nM?1μM). The proposed Ni NWs-based reduction approach will significantly simplify the traditional biological methods and has great potential in the application of Cyt c-related apoptotic studies.
关键词： nickel nanowires,surface-enhanced Raman spectroscopy,cytochrome c,label-free detection,apoptosis
更新于2025-09-04 15:30:14