查看更多>>摘要：Stable molybdenum disulfide quantum dots (MoS2 QDs) were synthesized using a simple method and embedded into chitosan (Chit) films with glucose oxidase (GOD) on the surface of a polyaniline (PANI) pre-electrodeposited ITO electrode, designated as Chit-MoS2 -GOD/PANI. At the prepared film electrode, the fluorescence property of MoS2 QDs as well as the catalytic properties of MoS2 QDs and GOD were well maintained and could be reversibly regulated by external stimuli, such as pH, potential, and the concentrations of glucose and ascorbic acid (AA) in the solution. By controlling the redox state of PANI with an externally applied voltage, the color of the film electrode switched between violet blue and nearly transparent, simultaneously quenching/dequenching the fluorescence signals from MoS2 QDs through Foster resonance energy transfer (FRET). The electrocatalytic signals toward hydrogen peroxide (H2O2), a product formed by biocatalysis between glucose and GOD, could be tuned through the catalytic capacity of MoS2 QDs in the films. Thus, an intelligent platform was built based on the film electrode with pH, potential, glucose and AA as inputs and UV-vis extinction (E), photoluminescent intensity (PL), and amperometric current (I) as outputs. Combinational logic operations such as a 4-input/5output logic network and sequential logic operations such as a keypad lock and a reprogrammable delay/data (D) flip flop was first simulated in a biocomputing system with the film-modified electrode. This work demonstrated the construction of a multiple stimulus-responsive system with dual-functional nanomaterials and provided a new approach for sequential logic operations for further applications in the information storage.
查看更多>>摘要：COVID-19 has erupted and quickly swept across the globe, causing huge losses to human health and wealth. It is of great value to develop a quick, accurate, visual, and high-throughput detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Here, we developed a biosensor based on CRISPR/Cas13a combined with recombinase polymerase amplification (RPA) to detect S and Orf1ab genes of SARS-CoV-2 within 30 min. Most important of all, we developed an automated, portable, and high-throughput fluorescence analyzer (APHFanalyzer) with a 3D-printed microfluidic chip for sensitively detecting SARS-CoV-2, which addressed aerosol contamination issue and provided a more accurate and high-throughput detection during the on-site detection process. The detection limits of S gene and Orf1ab gene were as low as 0.68 fM and 4.16 fM. Furthermore, we used the lateral flow strip to realize visualization and point of care testing (POCT) of SARS-CoV-2. Therefore, profit from the efficient amplification of RPA and the high specificity of CRISPR/Cas13a, APHF-analyzer and the lateral flow strip to simultaneous detection of S gene and Orf1ab gene would be applied as a promising tool in the field of SARS-CoV-2 detection.
查看更多>>摘要：Herein, glutathione-capped copper nanoclusters (CuNCs) and graphitic carbon nitride nanosheets (g-C3N4 NSs) were synthesized by a facile one-pot chemical reduction and directly thermal pyrolysis following ultrasonic exfoliation approaches, respectively. The introduction of Ce(III) (Ce3+) played dual functions in constructing a fluorescence-enhanced ratiometric nanoprobe (g-C3N4 NSs-Ce3+-CuNCs), i.e., triggering aggregation-induced emission of CuNCs and conjugating g-C3N4 NSs with CuNCs by virtue of electrostatic and coordination interactions. The as-fabricated nanohybrid displayed 460 and 625 nm dual-emitting peaks, attributing to the emission of g-C3N4 NSs and CuNCs, respectively. Upon addition of H2O2, the 625 nm emission was dramatically quenched, whereas the 460 nm emission remained nearly unchanged, thereby causing obvious color changes from purple to blue under a 365-nm UV lamp. A ratiometric fluorescent assay, based on g-C3N4 NSs-Ce3+-CuNCs, was devised for sensitive and visual detection of H2O2, which spanned the linear range of 2-100 mu M with a detection limit of 0.6 mu M. In the presence of glucose oxidase, the ratiometric nanoprobe could be simultaneously employed to detect glucose across the linear range of 1.6-320 mu M with a detection limit of 0.48 mu M. In milk and human serum samples, the fortified recoveries for H2O2 and glucose by the nanoprobe were in the range of 95.5-103.6% with RSDs < 3.8%. The real detection levels for glucose are consistent with those by a standard glucometer. As such, the ratiometric nanoprobe offers a promising methodology for several practical applications, such as point-of-care diagnosis and workplace health evaluations.
查看更多>>摘要：By rationally introducing Ce(III) and Tb(III) into a coordination polymer (CP), a series of lanthanide bimetallic coordination polymers (Tb:Ce-BCPs) has been prepared in this work. Compared with pure Tb-CP and Ce-CP, bimetallic Tb:Ce-BCPs show stronger and more stable ECL intensity, which is mainly attributed to the "dual sensitization effect" combined with the energy transfer from Ce(III) to Tb(III) and the antenna effect from the ligand to the center atoms of Ce(III) and Tb(III). In the meantime, after explore the ECL intensity and morphologies of all these Tb:Ce-BCPs, the results show that the morphologies and ECL intensities of Tb:Ce-BCPs can be adjusted by doping different molar ratios of Ce(III) in Tb:Ce-BCP. Excitingly, Ce(III) can also act as a coreaction accelerator, effectively promoting S2O8 2-to generate more SO4 center dot-, thereby enhancing the ECL intensity of Tb:Ce-BCP. That is to say, Ce(III) plays a triple role in Tb:Ce-BCP. Furthermore, the ECL strength of Tb:Ce-BCP decreased by only 1.8% and 3.5%, respectively after the modified electrode was scanned for 800 s and stored for one month. Enlightened by the excellent ECL properties of Tb:Ce-BCP, we modified Tb:Ce-BCP directly on the surface of electrode, and explored its application in electroanalytical chemistry through the detection of epinephrine (EP) and the detection limit is 33 fmol L-1. Significantly, our ECL sensing strategy promotes the application of lanthanides in ECL sensor and opens vast possibilities for the synthesis of a new generation of ECL emitter in electroanalytical fields.
查看更多>>摘要：The existence of cyanotoxins poses serious threats to human health, it is highly desirable to develop specific and sensitive methods for rapid detection of cyanotoxins in food and water. Due to the distinct advantages of aptamer including high specificity, good stability and easy preparation, various aptamer-based sensors (aptasensors) have been proposed to promote the detection of cyanotoxins. In this review, we summarize recent advance in optical and electrochemical aptasensors for cyanotoxins sensing by integrating with versatile nanomaterials or innovative sensing strategies, such as colorimetric aptasensors, fluorescent aptasensors, surface enhancement Raman spectroscopy-based aptasensors, voltammetric aptasensors, electrochemical impedance spectroscopy-based aptasensors and photoelectrochemical aptasensors. We highlight the accomplishments and advancements of aptasensors with improved performance. Furthermore, the current challenges and future prospects in cyanotoxins detection are discussed from our perspectives, which we hope to provide more ideas for future researchers.
查看更多>>摘要：Since the content levels of biomarkers at the early stage of many diseases are generally lower than the detection threshold concentration, achieving ultrasensitive and accurate detection of these biomarkers is still one of the major goals in bio-analysis. To achieve ultrasensitive and reliable bioassay, it requires developing highly sensitive biosensors. Among all kinds of biosensors, electrogenerated chemiluminescence (ECL) based biosensors have attracted enormous attention due to their excellent properties. In order to improve the performance of ECL biosensors, gold nanoparticles (Au NPs) have been widely utilized as signal amplification tags. The introduction of Au NPs could dramatically enhance the performance of the constructed ECL biosensors via diverse ways such as electrode modification material, efficient energy acceptor in ECL resonant energy transfer (ECL-RET), reaction catalyst, surface plasmon resonance (SPR) enhancer, and as nanocarrier. Herein, we summarize recent developments and progress of ECL biosensors based on Au NPs signal amplification strategies. We will cover ECL applications of Au NPs as a signal amplification tag in the detection of proteins, metal ions, nucleic acids, small molecules, living cells, exosomes, and cell imaging. Finally, brief summary and future outlooks of this field will be presented.
查看更多>>摘要：Biological nanopore-based single-molecule detection technology has shown ultrahigh sensitivity to various target analyte. But the detection scope of interesting targets is limited due to the lack of effective signal conversion strategies. In addition, conventional nanopore detection instruments are cumbersome, resulting nanopore detection can only be performed in laboratory. Herein, a customizable nanopore current amplifier is constructed to lower the cost and increase the portability of the nanopore instrument, and then an immobilized aptamerbased signal conversion strategy is proposed for alpha-hemolysin (alpha-HL) nanopore to detect small molecules (ochratoxin A, OTA). The presence of OTA in sample would trigger the release of probe single-strand DNA (ssDNA) from magnetic beads, which could subsequently cause current blockage in nanopore. The results show that the signal frequency of probe ssDNA has a linear relationship with the OTA concentration in the range of 2 x 10(1)~ 2 x 10(3) pmol/L. Compared to other methods, our sensing system has achieved an ultra-sensitive detection of OTA with the detection limit as low as 1.697 pmol/L. This strategy could broaden the scope of nanopore detection and have the potential for rapid and in-situ detection of other food contaminants in the future.
Kweon, Dae-HyukKim, Ji HongShin, Jae HwanCho, Chae Hwan...
8页
查看更多>>摘要：Identifying alternatives to antibodies as bioreceptors to test samples feasibly is crucial for developing next -generation in vitro diagnostic methods. Here, we aimed to devise an analytical method for detecting H1N1 viral proteins (hemagglutinin [HA] and neuraminidase [NA]) as well as the complete H1N1 virus with high sensitivity and selectivity. By applying biopanning of M13 peptide libraries, high affinity peptides specific for HA or NA were successfully identified. After selection, three different synthetic peptides that incorporated gold-binding motifs were designed and chemically synthesized on the basis of the original sequence identified phage display technique with or without two repeat. Their binding interactions were characterized by enzyme-linked immunosorbent assay (ELISA), square wave voltammetry (SWV), Time of flight-secondary ion mass spectroscopy (ToF-SIMS) and X-ray photoelectron spectroscopy (XPS). The binding constants (K-d) of HA BP1, HA BP2 and NA BP1 peptides were found to be 169.72 nM, 70.02 nM and 224.49 nM for HA or NA proteins by electrochemical measurements (SWV). The single use of HA BP2 peptide enabled the detection of either H1N1 viral proteins or the actual H1N1 virus, while NA BP1 peptide exhibited lower binding for real H1N1 virus particles. Moreover, the use of both HA BP1 and BP2 as a divalent capturing reagent improved sensor performance as well as the strength of the electrochemical signal, thereby exhibiting a dual synergistic effect for the electrochemical detection of H1N1 antigens with satisfactory specificity and sensitivity (limit of detection of 1.52 PFU/mL).
查看更多>>摘要：The effective trypsin purification methods should be established since trypsin plays a crucial role in biosome. In this work, a novel ternary magnetic composite adsorbent (MnFe2O4-MWCNTs@B-U-G) with the features of strong specific selectivity, good adsorption effect, simple and efficient separation process, no secondary pollution brought in was prepared by integrating the superior physicochemical properties of ternary based natural deep eutectic solvent, multi-walled carbon nanotubes and MnFe2O4. The property, composition and microtopography structure of MnFe2O4-MWCNTs@B-U-G were characterized in detail. Combined with magnetic solid-phase extraction, MnFe2O4-MWCNTs@B-U-G was utilized to adsorb trypsin. Response surface methodology experiment was prepared under Box-Behnken design to optimize the adsorption conditions and the results showed that the practical maximum adsorption capacity for trypsin was 1020.1 mg g-1. Besides, the adsorption isotherms, adsorption kinetics, regeneration studies and method validation studies were investigated systematically to evaluate the established adsorption separation system. Mechanism exploration proved that electrostatic interaction, hydrogen bonding interaction and chelation interaction were the dominant forces for the highperformance adsorption of trypsin. The activity of trypsin after elution had been analyzed by UV-vis spectrophotometer and CD spectrometer with three methods, which illustrated that the enzyme activity, conformation and secondary structure of trypsin did not change significantly during the adsorption-desorption process. In addition, the proposed method was successful and practical applicability to isolation trypsin from crude bovine pancreas. As a result, due to the superiority of the MnFe2O4-MWCNTs@B-U-G, the proposed method not only exhibites high-performance adsorption of trypsin, but also provides a green and sustainable potential value in the adsorption of biomacromolecule.
NSTL
Elsevier