A Highly Sensitive and Selective Label-free Electrochemical Biosensor with a Wide Range of Applications for Bisphenol A Detection

A label-free DNA-based electrochemical biosensor owning high sensitivity and selectivity has been established for detecting bisphenol A in a wide range of applications. Coupling the high electrochemical performance of graphene oxide-thionine-Au nanomaterial with the specific binding capacity of the aptamers to BPA, the monitoring of trace amount of BPA was realized, the detection limit was 3.3 pg ⋅ mL⁻¹ with strong anti-interference. Besides, using molecular docking, it was found that BPA binds to the bases DC-49, DC-51, DG-52, DG-53 and DA-63 on the aptamer via hydrogen bonding and π-π stacking interactions. Finally, the biosensor had been successfully applied in different real samples.     

Surface-Enhanced Raman Spectroscopy (SERS) for characterization SARS-CoV-2

We used SERS with silver nanoparticles (AgNPs) as the active substrate to develop a, simple, quick, and accurate method for the detection and characterization SARS-CoV-2 without the need for RNA isolation and purification. Inactivated SARS-CoV-2 was used. The SERS signals were more than 10⁵ times enhanced than the normal Raman (NR) spectra. The SERS spectra of SARS-CoV-2 fingerprint revealed pronounced intensity signals of nucleic acids; aromatic amino acid side chains: 1007 cm^?1 (Phe marker), 1095 cm^?1 (CN and PO₂^? markers), 1580 cm^?1 (Tyr, Trp markers). Vibrations of the protein main chain: 1144 cm^?1 (CN and NH₂ markers), 1221 cm^?1 (CN and NH markers), 1270 cm^?1 (NH₂ marker), 1453 cm^?1 (CHCH₂ marker). All of these biomolecules could be adsorbed on the AgNPs surface's dense hot patches. The intensity of the SERS band varied with the concentration of SARS-CoV-2, with a virus detection limit of less than 10³ vp/mL and RSDs of 20 %.     

In Vivo Detection of Hydrogen Sulfide in Brain and Cell

Hydrogen sulfide (H₂S), is proposed as a cytoprotectant and gasotransmitter, involving in many physiological processes and regulating of some diseases. In addition, H₂S is a small molecular with a minimum of steric hindrance compared with other reactive sulfur species. In physiological atmosphere, H₂S is mainly existent in HS⁻, which has a strong nucleophilicity and reducing potency. It also can precipitate with some metal ions forming metallic sulfides with high precipitation coefficient. In recent years, the researchers have a desire to develop methods to achieve real-time detection of H₂S in vivo, further understanding the physiology and pathology of H₂S. In this minireview, we summarize recent progress for detecting of H₂S in brain or cell and briefly expound the principle of methods with the comparison of the different methods between performance and temporal resolution.     

The electrochemical evaluation of antipsychotic drug (promethazine) in biological and environmental samples through samarium cobalt oxide nanoparticles

In this work, we developed a perovskite structured samarium cobalt oxide nanoparticles (SmCoO₃ NPs) with the aid of the co-precipitation method. The rare earth metal (Sm) and cobalt oxide combined to form a perovskite lattice structure. One-pot route synthesized SmCoO₃ NPs were scrutinized successfully through various physicochemical techniques. Concerning its effective thermal stability and electrical properties, the synthesized SmCoO₃ NPs have been effectively implemented in the electrochemical evaluation of promethazine hydrochloride (PHY) using cyclic voltammetry. The electrochemical detection of PHY was performed through SmCoO₃ NPs-modified glassy carbon electrode (GCE) and unmodified GCE. The electron transfer kinetics, effect of scan rate, the influence of pH, electroactive surface area, selectivity, and sensitivity have been studied. The electron charge transfer rate (R_ct) and electrolyte resistance (R_s) were calculated to be 105.59 (Ω) and 150 (Ω) in the ferricyanide probe, indicating great facilitation of the electron transfer between PHY and SmCoO₃ NPs deposited on the electrode surface. Further, the optimized SmCoO₃-modified GCE exemplifies excellent selectivity, storage stability, reproducibility, repeatability, detection limit (5 nM), sensitivity (0.594 μA μM^?1 cm^?2), and wide consecutive linear ranges, respectively. Besides, the proposed method has been effectively employed for the detection of PHY in the various real samples which reveals good recoveries of 95.40–99.17%.     

Eco friendly synthesis of fluorescent carbon dots for the sensitive detection of ferric ions and cell imaging

This study established a ferric ion (Fe³⁺) detection method as a result of the fluorescence quenching effect of Fe³⁺ on carbon dots (CDs). Specifically, we proposed, a green microwave synthesis route towards fluorescent CDs that requires only the brewer’s spent grain as starting materials. Transmission electron microscopy, X-ray diffraction, Fourier-transform infrared spectra and X-ray photoelectron spectroscopy were performed to investigate the CDs characteristic: morphology, size distribution, functional groups, and composition, respectively. The experimental results, which were run under optimal experimental conditions, indicated that the fluorescence intensity and concentration of Fe³⁺ were within the desired linear range (0.3–7 μM). The detection limit of this assay towards Fe³⁺ was 95 nM. The proposed method showed significant selectivity with respect to interfering ions. We evaluated the potential application of this method with tap water, lake water and fetal bovine serum as real samples. Additionally, the CDs could be served as superior bioimaging probes in Hela cells as a result of their excellent optical stability and good biocompatibility. In a word, the present study provides a new idea for CDs derived from the waste of agricultural products for detecting food or environmental contaminants and cell imaging.     

Recent Development of DNA-modified AIEgen Probes for Biomedical Application

A variety of DNA-based probes are utilized for the detections of multiple analytes and DNA nanotechnology has been thriving for recent decades and achieving numerous nanostructures,mainly focusing on DNA morphology modulation and multifunctional systems engineered into to the complicated works.Among the numerous detections,fluorescence method is a non-invasive,highly selective and sensitive means for varieties of applications,but their emissions are often compromised by the aggregation-caused quenching(ACQ)effect,which weakens their applications.The aggregation induced emission luminogens(AIEgens)are created with non emissive or weakly emissive in a low concentration but emit strong fluorescence in a high concentration with aggregated states.Herein,numerous functionalized AIEgens have been emerged and used for detection and imaging and DNA-modified AIEgen probes are introduced.In this vein,here we report the progress on DNA-modified AIEgen probes in recent years and highlight their conjugation strategies including covalent bonding,electrostatic interaction and their applications of biosensing.Moreover,multiple DNA strands are needed to introduce into the DNA-modified AIEgen probes for more purposes.At the end,some challenges are mentioned to discuss the new trend of DNA-modified AIEgen probes.     

Molecular engineering and biomedical applications of ultra-sensitive fluorescent probe for Ag+

A series of probes KJ-x (x = 1−3) with carbon chains of different lengths based on the matrix of rhodamine B were engineered to detect Ag⁺ in aqueous solution in this work. Among them, KJ-1 is selected as the best option after in vitro investigation in view of its most sensitive and rapid response to Ag⁺, whose possible sensing mechanism is studied by experimental investigation and theoretical calculation. To identify the practical application of the probe, the detection of Ag⁺ in nonantibiotic fungicide Silver&Health and differentiation between normal hepatocytes and hepatoma cells using confocal imaging was conducted.     

贵金属基纳米酶的研究进展

贵金属纳米材料在纳米尺度具有独特的光学、 电学性质及优异的催化性能, 是一类重要的功能纳米材料. 基于贵金属材料的纳米酶研究是贵金属纳米材料在生物医学领域的一个前沿研究方向. 贵金属基纳米酶具有特殊的光学性质、 较好的化学稳定性、 可调控的类酶活性及良好的生物相容性, 是目前纳米生物医学领域的热点研究材料. 本文总结了贵金属基纳米酶的活性种类、 活性机理、 活性调控以及在生物医学等领域的潜在应用.     

Morphology controllable conjugated network polymers based on AIE-active building block for TNP detection

Luminescent conjugated network polymer is one of the most promising chemo-sensors owing to their good chemical/optical stability and multiple functionalization.Herein,three conjugated network polymers were prepared by using aggregation-induced emission active 1,1,2,2-tetrakis(4-formyl-(1,1'-biphenyl))-ethane(TFBE) unit as monomer and hydrazine as linker.Through regulating the synthetical condition,the polyme ric network can form either unifo rm two-dimensional azine-linked nanosheets(ANS),conjugated microporous polymers(A-CMP) or covalent organic frameworks(A-COF).All of these polymers exhibited good stability and high fluorescence quantum efficiency with the quantum yield of6.31% for A-NS,5.26% for A-CMP,and 5.80% for A-COF,as well as fast and selective fluorescence quenching response to 2,4,6-trinitrophenol(TNP).And the best TNP sensing performance with the Stern-Volmer constants(K_(sv)) values up to 8 × 10~5 L/mol and a detection limit of 0.09 μmol/L was obtained for A-NS.The study explores various strategies to construct conjugated polymers with different nanoarchitectures based on the same building block for sensitive detection of explosives.