- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Chitosan-carbon quantum dots as a new platform for highly sensitive insulin impedimetric aptasensor
摘要： Considering the importance of measuring insulin in the prevention and diagnosis of diabetes-related illnesses, here we introduced an ultrasensitive electrochemical aptamer-based sensor for detection of insulin in human blood serum. In this research, carbon quantum dots (CQDs) were synthesized using simple, fast and cheap methods from candle soot. By dispersion of the CQDs in chitosan (Chi) matrix, homogenous CQD-Chit nano-composite was obtained. The experimental results demonstrate the good advantages of proposed CQD-Chit nano-composite, such as homogeneity, high stability and multiple amino groups for covalent immobilization of aptamer and fabrication of highly selective insulin aptasensor. CQD-Chit nano-composite was characterized by the transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDAX), Fourier transform infrared (FTIR) spectroscopy and electrochemical techniques. Under the optimized conditions with electrochemical impedance spectroscopy technique, a linear response ranges from 0.5 nM to 10 nM with the sensitivity of 80.07 ?/nM and the very low detection limit of 106.8 pM was obtained for insulin detection. The fabricated aptasensor is validated in comparison with standard methods for detection of insulin in human blood serum. Also, the analytical performances of the fabricated aptasensor can be a superiority compared to the current insulin electrochemical biosensors.
关键词： Modifies electrode,Biosensor,Impedimetric aptasensor,Carbon quantum dots,Insulin detection
更新于2025-09-11 14:15:04
-
Two-dimensional plasmonic biosensing platform: Cellular activity detection under laser stimulation
摘要： Combining biosensors with nanoscience provides great advantages such as being label-free and real time, highly sensitive, and small in size, as well as providing a low limit of detection and integration to other systems. That is why plasmonics finds various applications in drug detection, food safety, agriculture, photothermal therapy, etc. In this paper, we have fabricated a two-dimensional plasmonic grating biosensor using a soft lithography technique, which has eliminated some disadvantages of conventional plasmonic structures like expensive fabrication cost, inflexibility, and lack of mass production. On the other hand, we benefited from infrared neural stimulation for regulating membrane depolarization, which was based on photothermal mechanism and provided a contact-free and high spatial/temporal resolution. Eventually, the membrane depolarization of two different cell types of Hep G2 and mesenchymal stem cells cultured on two-dimensional plasmonic structure has been investigated under infrared neural stimulation. After preparing the soft plasmonic crystal, its reflection spectra and respective ellipsometry parameters were analyzed before and after cell culture with/without stimulation (near-infrared immune region ～1450 nm). By comparing the obtained ellipsometry results for HEP G2 and mesenchymal stem cells, it is observed that the behavior of two cell types with respect to IR stimulation was the same as well as providing us the possibility of distinguishing the level of membrane depolarization under various stimulating frequencies. The strength of this integrated system for membrane depolarization detection has been shown experimentally, which can open new avenues toward neuroplasmonic application in the future.
关键词： infrared neural stimulation,membrane depolarization,ellipsometry,soft lithography,plasmonic biosensor
更新于2025-09-11 14:15:04
-
Sandwich-type Surface Stress Biosensor Based on Self-Assembled Gold Nanoparticles in PDMS Film for BSA Detection
摘要： Polydimethylsiloxane (PDMS) films compositing with gold nanomaterials have drawn increasing interest for their application in biosensors. However, gold and PDMS exhibit poor compatibility, limiting their sensitivity in biosensing. Herein, we reported a surface stress biosensor based on a gold nanoparticle–PDMS (AuNP–PDMS) composite film to detect bovine serum albumin (BSA). The AuNP–PDMS film was fabricated by in-situ reduction of PDMS and further reduction of glucose. The compatibility between gold and PDMS was improved via two-step reduction of AuNPs. The surface stress biosensor can specifically detect BSA molecules within 0–50 μg/mL concentration range by using the direct assay and the sandwich assay. The sandwich assay amplified the surface stress and reduced the limit of detection to 0.035 μg/mL, which is lower than that achieved by the direct assay. The sandwich-type biosensor also exhibits stability, repeatability and specificity. This study is expected to drive the development of new methods for biomolecule detection.
关键词： surface stress biosensor,BSA detection,self-assembly AuNPs,sandwich assay
更新于2025-09-11 14:15:04
-
Nitrogen Doped Carbon Quantum Dots Modified by Lens culinaris β-Galactosidase as a Fluorescent Probe for Detection of Lactose
摘要： Nitrogen doped carbon quantum dots (NCQDs) were synthesized via hydrothermal route. The NCQDs are thermally and optically stable with high flouresence yield. For the synthesis of NCQDs, citric acid and urea was taken as carbon and nitrogen sources, respectively. The Transmission Electron Microscopy (TEM) of these quantum dots revealed nearly spherical shape and average size of 1.5 nm, which was calculated using Image J software. The quantum dots were also well-characterized using spectroscopic techniques such as FTIR, UV-Visible absorption and fluorescence. These synthesized and characterized dots were utilized for selective detection of lactose in Milli Q water. The bioprobe provide a wide linear range varying from (10.00–77.41) μM with limit of detection 11.36 μM and sensitivity equal to (0.0065 ± 0.0002) μM?1.
关键词： Lens culinaris,β-Galactosidase,Biosensor,Fluorescence,Lactose
更新于2025-09-11 14:15:04
-
Coupling between surface plasmon polariton and planar waveguide modes in the biosensor based on metal–insulator–metal/planar waveguide structure
摘要： In this paper, we propose a high performance biosensor which allows the coupling between surface plasmon polariton (SPP) mode in metal-insulator-metal waveguide and planar waveguide (PWG) mode. The reflection curve exhibits a sharp dip originated from PWG mode when there is a weak coupling between SPP and PWG modes. The strong coupling between SPP and PWG modes results in symmetric Fano resonance and plasmon-induced transparency. The sensitivities of PWG mode dip and Fano resonance achieve 9733 and 7050 RIU?1, respectively, which are enhanced by 2～3 orders of magnitude compared to those of conventional surface plasmon resonance sensors.
关键词： Coupling,Planar waveguide mode,Surface plasmon polariton mode,Biosensor,Fano resonance
更新于2025-09-11 14:15:04
-
Quasi-D-Shaped Fiber Optic Plasmonic Biosensor for High-Index Analyte Detection
摘要： In this paper, we propose a highly sensitive quasi-D-shaped fiber optic biosensor for detection of high refractive index (RI) liquid analytes via surface plasmon resonance. The main mechanism of sensing is interplay between photonic crystal fiber fundamental mode and plasmonic mode which leads to formation of different resonance peaks depending on the analyte RI. We numerically analyze the structure sensitivity to design parameters and demonstrate the sensing performance of the proposed biosensor using both spectral sensitivity and amplitude sensitivity methods. The proposed biosensor has a RI detection range of 0.15 refractive index unit (RIU) from 1.45 to 1.6. The sensor exhibits linear sensing performance with a RI spectral sensitivity of 9300 nm/RIU for analyte RI ranging from 1.45 to 1.525, 1176 nm/RIU for analyte RI ranging from 1.525 to 1.6 and in particular, 11800 nm/RIU for analyte RI between 1.475 and 1.5. Furthermore, an average RI sensitivity of 4800 nm/RIU for analyte RI ranging from 1.45 to 1.6 is demonstrated. We also study the amplitude sensitivities of the proposed sensor which show promising maximum values of 183.6 RIU-1 for 785 nm excitation and 820 RIU-1 for 1050 nm excitation. Due to the simple structure of the proposed biosensor, large detection range, high sensitivity and promising linear sensing performance, the proposed biosensor can be a promising candidate for detecting various high RI chemical and biochemical samples.
关键词： plasmonic biosensor,photonic crystal fiber,high index analyte detection,Fiber optic sensor,refractive index sensing
更新于2025-09-11 14:15:04
-
Highly sensitive and tunable terahertz biosensor based on optical Tamm states in graphene-based Bragg reflector
摘要： A highly sensitive and tunable biosensor at terahertz (THz) frequencies is proposed by using a composite structure of graphene and one-dimensional photonic crystal. The theoretical analysis and simulation results show that the sensitivity and figure-of-merit of the biosensor can reach 517.9°/RIU and 1222.9RIU-1, respectively. The high sensitivity of the biosensor originates from the excitation of optical Tamm states caused by graphene-based distributed Bragg reflector. By varying the voltage on graphene, we can electrically control the sensitivity and figure-of-merit of the biosensor. Furthermore, we have shown that the biosensor has a wide range (1.40~1.70) for measuring the refractive index of the sensing medium. We believe the biosensor has a good application prospect in the field of biological detection.
关键词： figure-of-merit,terahertz biosensor,Bragg reflector,sensitivity,optical Tamm states,graphene
更新于2025-09-11 14:15:04
-
Fabrication of a Tyrosine Responsive Liquid Quantum dots based Biosensor Through Host-Guest Chemistry
摘要： Design and fabrication of a smart liquid quantum dots (LQDs) with high biomolecules selectivity and specificity remains a challenge. Herein, a multifunctional calix[4]arene derivatives (PCAD) was rationally designed and applied to fabricate a Tyr-responsive CdSe-LQDs system through host-guest chemistry. Such this biosensor displays an outstanding fluorescence/macroscopic response for Tyr and reversible fluidic features due to the hydrogen interaction between the PCAD of CdSe-LQDs and Tyr. These excellent results highlighted CdSe-LQDs as a promising platform for biological molecules recognition and separation in the future.
关键词： Calix[4]arene,Liquid Quantum dots,Biosensor,Host-Guest Chemistry,Tyrosine detection
更新于2025-09-11 14:15:04
-
A high sensitive SH-SAW biosensor based 36° Y-X black LiTaO3 for label-free detection of Pseudomonas Aeruginosa
摘要： A label-free and high sensitive shear horizontal surface acoustic wave (SH-SAW) biosensor for the nucleic acid detection of Pseudomonas Aeruginosa was developed in this work. An effective detection cell was fabricated by dint of acrylic material. The base frequency of the SH-SAW biosensor fabricated on 36°Y-X rotated black LiTaO3 piezoelectric substrate was 210 MHz. The self-assembled monolayer was formed on the gold surface of the sensitive area, and the increase of mass loading in the sensitive area leads to phase shift of SH-SAW. In this work, the detection limit has been improved by 3–4 times than that in our previous works, which is 1 nmol/L for the nucleic acid of the Pseudomonas Aeruginosa. And the phase shifts related to detection sensitivity are also elevated to 4 ° after the specific binding of the ss-DNA probes and the complementary sequences. In this study, the plot of phase shift against the logarithm of concentration of Pseudomonas aeruginosa nucleic acid was found to be linear over the range from 0.1 nmol/L to 1000 nmol/L with a correlation coefficient 0.98777. The detection limit as low as 0.28 nmol/L was achieved for Pseudomonas aeruginosa nucleic acid in this paper.
关键词： SH-SAW,Biosensor,Black LiTaO3,Limit of detection,Phase shift
更新于2025-09-11 14:15:04
-
The phenomenon of fluorescence in immunosensors
摘要： The phenomenon of fluorescence in immunosensors is described in this paper. Both structure and characteristics of biosensors and immunosensors are presented. Types of immunosensors and the response of bioreceptor layers to the reaction with analytes as well as measurements of electrochemical, piezoelectric and optical parameters in immunosensors are also presented. In addition, detection techniques used in studies of optical immunosensors based on light-matter interactions (absorbance, reflectance, dispersion, emission) such as: UV/VIS spectroscopy, reflectometric interference spectroscopy (RIfs), surface plasmon resonance (SPR), optical waveguide light-mode spectroscopy (OWLS), fluorescence spectroscopy. The phenomenon of fluorescence in immunosensors and standard configurations of immunoreactions between an antigen and an antibody (direct, competitive, sandwich, displacement) is described. Fluorescence parameters taken into account in analyses and fluorescence detection techniques used in research of immunosensors are presented. Examples of immunosensor applications are given.
关键词： absorbance,UV/Vis,fluorescence,immunosensor,biosensor
更新于2025-09-11 14:15:04