- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
The Conductivity of the Monolayer of DNA a?? Quantum Dot Complexes in the Presence of Intercalating Charged Ligands
摘要： The resistance of a monolayer of complexes of the double-stranded DNA with quantum dots were computed. It was shown that with the non-competitive DNA hybridization and in the presence of monovalent positively charged ligands in the solution, a decrease in resistance occurs as compared to that for uncharged ligands. It is shown that the charged ligands enhance the sensitivity of the DNA chips as compared to the uncharged ones.
关键词： DNA,biosensor,intercalator,conductivity
更新于2025-09-23 15:19:57
-
TiO2 nanotubes modified with polydopamine and graphene quantum dots as a photochemical biosensor for the ultrasensitive detection of glucose
摘要： Rapid and sensitive detection of glucose concentrations is very important for human health. Herein, an ultrasensitive photoelectrochemical dual-electron-acceptor biosensor was constructed by modifying the TiO2 nanotubes (NTs) with polydopamine (PDA) and amino-functionalized graphene quantum dots (N-GQDs)/GOx. PDA is grown on the top of the TiO2 NTs by the electropolymerization, and N-GQDs are loaded into the inner of the TiO2 NTs by a microwave-assisted method. The TiO2 NTs/PDA/N-GQD dual-electron-acceptor biosensor exhibited a highly enhanced photoelectric response, excellent electron–hole separation efficiency, low detection limit (0.015 mM), wide linear range (0–11 mM) and ultrahigh sensitivity (13.6 lA mM-1 cm-2). The prepared biosensor reflected high selectivity and excellent stability. This work also provides new insights into other optoelectronic biosensors.
关键词： photochemical biosensor,polydopamine,graphene quantum dots,TiO2 nanotubes,glucose detection
更新于2025-09-23 15:19:57
-
Fluorometric virus detection platform using quantum dots-gold nanocomposites optimizing the linker length variation
摘要： In this study, a tunable biosensor using the localized surface plasmon resonance (LSPR), controlling the distance between fluorescent CdZnSeS/ZnSeS quantum dots (QDs) and gold nanoparticles (AuNPs) has been developed for the detection of virus. The distance between the AuNPs and QDs has been controlled by a linkage with a peptide chain of 18 amino acids. In the optimized condition, the fluorescent properties of the QDs have been enhanced due to the surface plasmon effect of the adjacent AuNPs. Successive virus binding on the peptide chain induces steric hindrance on the LSPR behavior and the fluorescence of QDs has been quenched. After analyzing all the possible aspect of the CdZnSeS/ZnSeS QD-peptide-AuNP nanocomposites, we have detected different concentration of influenza virus in a linear range of 10?14 to 10?9 g?mL?1 with detection limit of 17.02?fg?mL?1. On the basis of the obtained results, this proposed biosensor can be a good alternative for the detection of infectious viruses in the various range of sensing application.
关键词： Quantum dots,Localized surface plasmon resonance,Biosensor,Peptide,Influenza virus,Gold nanoparticle
更新于2025-09-23 15:19:57
-
[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - A new model for predicting bifacial PV modules performance: first validation results
摘要： We experimentally demonstrate a surface-plasmon-resonance-based sensor capable of detecting polysaccharide molecules, such as Xanthan gum. Experimental results demonstrate that by attaching Concanavalin A to the gold nanothin-film chip of the sensor, a linear response of the change in reflected optical power to the dissolved Xanthan gum concentration is observed, demonstrating the ability of the developed sensor to detect Xanthan gum concentrations up to 0.22 g/L.
关键词： surface plasmon resonance,desalination,Biosensor,optical sensors,xanthan gum
更新于2025-09-23 15:19:57
-
Highly Sensitive Photoelectrochemical Biosensor Based on Quantum Dots Sensitizing Bi <sub/>2</sub> Te <sub/>3</sub> Nanosheets and DNA-Amplifying Strategies
摘要： In this work, the Bi2Te3 nanosheets treated by N-vinyl-Pyrrolidinone (NVP) showed the highly sufficient and stable photocurrent for being served as novel photoactive material. Accordingly, with CdTe quantum dots (QDs) sensitizing the Bi2Te3 nanosheets, a photoelectrochemical (PEC) biosensor coupling of DNA amplifying strategies was constructed for sensitive miRNA-21 detection. Initially, the Bi2Te3 nanosheets on electrode have conductive surface states with dissipationless electronic property, thus providing a highly stable photocurrent as well as large surface-to-volume ratio. Then, with the participation of target miRNA-21 and auxiliary DNA, the strand displacement amplification (SDA) took place, thereby opening substantial DNA hairpins for triggering next hybridization chain reaction (HCR). Through the HCR, long DNA tails decorated with CdTe QDs could thus be assembled on electrode for enhancing the photocurrent of Bi2Te3 nanosheets. As a result, the proposed PEC biosensor showed a wide detection range from 10 fM to 100 pM with a detection limit (LOD) of 3.3 fM, displaying a promising avenue to construct simply, ultrasensitive and stable analytical techniques and a tremendous potential in bioanalysis and early clinical diagnosis.
关键词： DNA amplifying strategies,Bi2Te3 nanosheets,sensitive detection,CdTe quantum dots,photoelectrochemical biosensor
更新于2025-09-23 15:19:57
-
SiRNA-directed self-assembled quantum dot biosensor for simultaneous detection of multiple microRNAs at the single-particle level
摘要： MicroRNAs are essential post-transcriptional regulators and may act as the noninvasive biomarker for disease diagnosis. Sensitive and multiplexed detection of microRNAs may facilitate the accurate and early clinical diagnosis, but the available methods are usually compromised by using organic dyes as the signal probes, laborious chemical and enzymatic manipulations, and the complicated reaction schemes. Here we reported a siRNA-directed self-assembled quantum dot (QD) biosensor for facile and simultaneous detection of multiple microRNAs. In this biosensor, the binding of microRNA targets with corresponding QD nanoprobes leads to the formation of siRNA duplexes, which not only induces the spectrally resolved coding of microRNAs, but also facilitates the assembly of QDs:magnetic nanoparticle bioconjugates for the isolation and enrichment of target microRNAs. The disassembled QDs can be sensitively detected by single-molecule detection, enabling quantitatively sensing of microRNAs at the single-particle level. This biosensor employs only QDs as the signal reporters, which can simultaneously detect multiple microRNAs from the same sample and achieves femtomolar sensitivity and single-base mismatch selectivity without the involvement of any target labeling and amplification steps. Moreover, it can be successfully applied for simultaneous detection of circulating microRNAs in clinical serum samples, holding great potential in non-invasive early diagnosis and biomedical researches.
关键词： Quantum dot,SiRNA,Fluorescent biosensor,MicroRNA,Single-particle detection
更新于2025-09-23 15:19:57
-
A phenylboronate-based SERS nanoprobe for detection and imaging of intracellular peroxynitrite
摘要： A surface-enhanced Raman scattering (SERS) based nanoprobe was developed for detection and imaging of endogenous peroxynitrite in living cells. The probe was fabricated by assembling 3-mercaptophenylboronic acid pinacol ester onto the surface of gold nanoparticles (AuNPs). The detection of peroxynitrite is accomplished via measurement of the changes in the SERS spectra (at 882 cm?1) that are caused by the reaction between probe and peroxynitrite. The probe has a fast response (<30 s), a 0.4 μM lower detection limit and a wide linearity range from 5.0 × 10?7 to 1.0 × 10?4 M. It is biocompatible and highly stable on storage and under various pH conditions. Both the reaction and the SERS signal are highly specific over other species. The nanoprobe was successfully applied to SERS imaging of peroxynitrite that is produced in macrophages under oxidative stress. Conceivably, the method has a most viable tool for use in studies on peroxynitrite-related physiological and pathological processes.
关键词： Surface-enhanced Raman scattering,Boronate ester,Specific reaction,Reactive oxygen species,Gold nanoparticles,Living cell,Oxidative stress,Biosensor
更新于2025-09-23 15:19:57
-
Approach for the improvement of sensitivity and sensing speed of TFET-based biosensor by using plasma formation concept
摘要： In this work, a new design of dual-gate source electrode (SE) dielectric-modulated tunnel field-effect transistor (TFET) biosensor with improved sensitivity and sensing speed has been presented. For this, P + (source) I (channel) N + (drain) type conventional TFETs structure is initially considered for comparison. Further to this, for the first time, an additional electrode is placed over the physically doped source region of the conventional biosensor with the negative supply voltage for extension of the cavity over the source region. The use of extra SE with negative supply voltage for the formation of cavity over the source region overcome the issues related to the formation of abrupt junction (at source/channel junction) and solubility limit of silicon material by the formation of a plasma layer of holes near to Si/HfO2 interface in the source region. Moreover, the presence of extra biomolecules in the source cavity region of the proposed device further increases the concentration of plasma layer of holes near to Si/HfO2 due to better coupling of SE and source region which is responsible for the improvement in sensing capability and sensing the speed of TFET biosensor. In this concern, a comparative investigation has been performed.
关键词： sensing speed,biosensor,plasma formation,TFET,sensitivity
更新于2025-09-23 15:19:57
-
Bimodal detection of proteins by 129Xe NMR and fluorescence spectroscopy
摘要： The full understanding of biological phenomena involves sensitive and non-invasive detection. Here we report the optimization of a probe for intracellular proteins that combines the advantages of fluorescence and hyperpolarized 129Xe NMR detection. The fluorescence detection part is composed of six residues containing a tetracysteine tag (-CCXXCC-) genetically incorporated into the protein of interest and of a small organic molecule, CrAsH. CrAsH becomes fluorescent when it binds to the tetracysteine tag. The part of the biosensor that enables 129Xe NMR detection, linked to the CrAsH moiety by a spacer, is based on a cryptophane core fully suited to reversibly host xenon. We benchmark three different peptides containing the tetracysteine tag and four organic biosensors of different stereochemistry to propose the best couple, fully suited for the in vitro detection of proteins.
关键词： biosensor,tetracysteine-tag,fluorescence,129Xe NMR,cryptophane,fluorescent protein
更新于2025-09-19 17:15:36
-
Understanding the Citric Acid-Urea Co-Directed Microwave Assisted Synthesis and Ferric Ion Modulation of Fluorescent Nitrogen Doped Carbon Dots: A Turn On Assay for Ascorbic Acid
摘要： Herein, nitrogen doped carbon dots (NCDs) were synthesised from citric acid and urea via a previously reported microwave assisted route. The NCDs shows emission maximum at 500 nm on excitation at 400 nm. The fluorescence of NCDs decreases slightly with increase in basicity of solution up to pH 7.5 and then increases again after pH 8.5, along with a blue-shift in tested alkaline pH. This pH dependent blue-shift indicates the presence of both carboxyl?carboxylate and phenol?phenolate prototropic equilibrium in NCDs. Due to the special interaction of these phenolates and carboxylates on NCDs surface with di- or tri- valent heavy transition metal ions; it is demonstrated that ferric ion (Fe3 + ion) can quench the fluorescence of NCDs. This Fe3 + induced static quenching of NCDs is a collaborative effect of inner filter effect, aggregation and ferromagnetism. However, Ascorbic acid (AA) can recover the fluorescence of Fe3 + quenched NCD with detection limit as low as 96 μM. This detection strategy has good selectivity towards AA over other antioxidants, saccharides, proteins and neurotransmitters. Furthermore, (spiked) human serum and (spiked) human urine were analysed and found good recovery percentage.
关键词： Fluorescence,Ascorbic Acid,Biosensor,Inner Filter Effect,Iron(III),Carbon Dots
更新于2025-09-19 17:15:36