- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Sensitivity comparison of graphene based surface plasmon resonance biosensor with Au, Ag and Cu in the visible region
摘要： In this paper, the sensitivities of graphene based surface plasmon resonance (SPR) biosensors with gold (Au), silver (Ag) and copper (Cu) layers are numerically analyzed and compared in the visible region. As the wavelength of the incident light increases, the sensitivity of a monolayer graphene based SPR biosensor with a specific metal (Au, Ag or Cu) layer firstly increases to a maximum value (called peak sensitivity), and then decreases. It is found that the peak sensitivity of a monolayer graphene based SPR biosensor with Ag layer (300.26 °/RIU) is 119% or 200% higher than the one of SPR biosensor with Au (137.02 °/RIU) or Cu (136.24 °/RIU) layer. In addition, with the increase of number of graphene layers, the peak sensitivity of the proposed SPR sensor with different metal layer decreases, but the resonance wavelength increases. Moreover, the origin of sensitivity enhancement is also investigated by analyzing the electric field intensity inside the proposed SPR biosensors. It is believed that a sensitivity comparison of graphene based SPR biosensors with Au, Ag and Cu layer is important and can be helpful for highly sensitive biosensors development.
关键词： graphene,surface plasmon resonance,biosensor,visible region,sensitivity
更新于2025-09-19 17:15:36
-
A universal photoelectrochemical biosensor for dual microRNAs detection based on two CdTe nanocomposites
摘要： Various diseases are closely related with simultaneous changes of multiple miRNAs expressions levels. It’s of great significance to develop photoelectrochemical (PEC) biosensors for multiple miRNAs detection for both clinical diagnosis and biological mechanisms research. In this work we designed a novel PEC biosensor for simultaneous dual miRNAs detection for the first time. Two nanocomposites CdTe loaded on carbon nitrides nanosheets (CdTe-C3N4) with anodic photocurrent and CdTe loaded on 3D graphene hydrogel (CdTe-3DGH) with cathodic photocurrent were prepared and showed enhanced PEC performances. Photocurrents of the two nanocomposites can be clearly distinguished at corresponding critical voltage. Then probe DNA1 and DNA2 were combined with the CdTe-3DGH and CdTe-C3N4 NCs through covalent binding respectively. With the competition hybridization reaction between target miRNAs and the complementary DNA (cDNA), concentrations of miRNA141 and miRNA21 may be sensitively quantified by the respective photocurrents change. Compared with traditional PEC biosensors, this design didn’t require any additional equipment and can provide a higher detection efficiency, which has a good universality and expansibility for the fabrication of multiplex PEC assays.
关键词： photoelectrochemical,microRNA,dual targets,biosensor
更新于2025-09-19 17:15:36
-
Performance of Arrayed Microring Resonator Sensors with the TriPleX Platform
摘要： Integrated-optical (bio) chemical sensors are more and more commercialized, mainly because of their high intrinsic sensitivity in combination with the possibilities they offer for integration in optofluidic devices. The microring resonator (MRR), for example, is a very feasible structure to be used as microarray sensor element for multiplex biosensing. Fabrication of MRRs has been described in the case of the TriPleX platform employing well-defined stacks of stoichiometric Si3N4 and SiO2 material. This platform allows for a wide variety of applications, due to its intrinsic low loss and its transparency for the VIS/NIR wavelength range. In the present paper, we describe the recent achievements in the characterization of arrays of these MRRs regarding temperature sensitivity, refractive index sensitivity and protein immobilization performance. Furthermore, the use of a reference channel/reference MRR is demonstrated in order to show the advantage of compensation of unintended change in temperature or sample composition. The refractive index sensitivity was determined to be 104 nm/RIU and the limit of detection was about 2 × 10-6 RIU. MRRs appeared to behave very comparable (expressed as the coefficient of (intra-array) variation (CV)) regarding the response to temperature (CV≈0.3%) as well as refractive index (CV<0.1%). Furthermore, it is shown that protein immobilization onto the different MRRs of the same arrays can be realized in a comparable way (CV<3%). A good comparability (i.e., a low variation) in these aspects allows for the use of internal referencing in order to compensate for unintended change in temperature or refractive index and also helps to attain a high assay precision in the ultimate biosensing application. Ongoing research is focused on the integration of more functionality on chip and further miniaturization in order to allow for fabrication of complex, though affordable, sensor devices.
关键词： Refractive index,Biosensor,MRR,Sensor array,Integrated optics,Microring resonator
更新于2025-09-19 17:15:36
-
Near-Infrared Afterglow Semiconducting Nano-polycomplexes for Multiplex Differentiation of Cancer Exosomes
摘要： As nanoscaled extracellular vehicles inheriting genetic and protein information from source cells, detection of exosomes is promising for early diagnosis of cancer. However, optical sensors with high specificity and low medium background remain challenging for detection of exosomes. We herein develop the first luminescent nanosensor that bypasses real-time light excitation for multiplex differentiation of cancer exosomes. Such an afterglow luminescent nanosensor is composed of a near-infrared (NIR) semiconducting polyelectrolyte (ASPN) electrostatically complexed with a quencher-tagged aptamer. The afterglow signal of the nanocomplex (ASPNC) is initially quenched due to the efficient electron transfer between ASPN and the quencher. However, the presence of aptamer-targeted exosome increases ASPN/quencher distance, turning on afterglow signal. Because the afterglow detection is conducted after cessation of light excitation, the sample background signal is greatly minimized, affording the limit of detection that is nearly two orders of magnitude lower than fluorescence detection in cell culture medium. More importantly, ASPNC can be easily tailored to detect different exosomal proteins simply by changing the sequence of aptamer. Such a structural versatility of ASPNC enables orthogonal analysis of multiple exosome samples, potentially permitting accurate identification of the cellular origin of exosomes for cancer diagnosis.
关键词： optical imaging,semiconducting polymer,nanomaterials,biosensor,exosome
更新于2025-09-19 17:15:36
-
Construction of novel xanthine biosensor by using Zinc Oxide (ZnO) by biotemplate method for fish freshness detection
摘要： In the food industry, fish is a product with a short shelf life, and xanthine attracts much attention as an indicator of fish freshness. In this study, we demonstrated a simple assay system containing Zinc Oxide (ZnO) and xanthine oxidase (XOD) for specific and quantitative detection of xanthine. ZnO nanomaterial have been successfully synthesized using biotemplated method. A mechanism is based on the fluorescence quenching of ZnO via electron transfer mechanism, which is caused by the hydrogen peroxide (H2O2) that is produced from the XOD-catalyzed oxidation of xanthine. By virtue of the specific response, the present assay allowed for the selective determination of xanthine in the range of 3.30×10-10-6.67×10-7 mol/L and 2.67×10-6-2.67×10-4 mol/L with a detection limit of 1.30×10-10 mol/L. The proposed method was successfully applied to the determination of xanthine in real fish samples with satisfactory results.
关键词： Biotemplated method,Xanthine oxidase,Fish Biosensor,ZnO,Xanthine
更新于2025-09-19 17:15:36
-
[IEEE 2018 IEEE SENSORS - New Delhi, India (2018.10.28-2018.10.31)] 2018 IEEE SENSORS - C-MEMS Derived Glassy Carbon Electrodes as Sensitive Electrochemical Biosensors
摘要： Electrochemical biosensors have high potential for application in point of care setting, as they involve simpler measurements compared to optical counterparts and can operate in complex analyte. In this context, carbon electrodes have been widely explored since it is more stable than other metals. Pyrolyzed carbon electrodes have been deployed for protein sensing but the detection limit achieved is not satisfactory, probably due to the selection of the carbon precursor. In this paper, we have prepared glassy carbon electrodes using conventional carbon-microelectromechanical systems (C-MEMS) process. SU-8 photoresist has been used as the carbon precursor. The carbon thin film electrodes have then been tested by cyclic voltammetry measurements in the potential range of -800 mV to 800 mV in presence of 10 mM potassium ferricyanide solution. The samples have been immobilized with anti-Hep-B monoclonal antibody. The presence of antibodies has been further confirmed by UV-VIS spectrophotometry. It has been observed that the current peak reduces distinctly and the fractional change in current magnitude is around 30% and 83% at the potential of 175 mV for 1 fM and 1 pM concentrations respectively. Hence, the presented study is the proof-of concept of sensitive electrochemical detection of Hep-B using functionalized glassy carbon electrodes which when integrated with a low cost microfluidic platform can become suitable for point-of-care diagnostics.
关键词： biosensor,cyclic voltammetry,glassy carbon,C-MEMS,electrochemical sensing,Hep-B
更新于2025-09-19 17:15:36
-
Cascaded-Microrings Biosensors Fabricated on a Polymer Platform
摘要： Polymer-based single-microring biosensors usually have a small free spectral range (FSR) that hampers the tracing of the spectrum shifting in the measurement. A cascade of two microring resonators based on the Vernier effect, is applied in this article in order to make up for this defect. A small FSR difference between the reference microring and the sensing microring is designed, in order to superpose the periodic envelope signal onto the constituent peaks, which makes it possible to continuously track the spectrum of the sensor. The optical polymer material, Ormocore, which has a large transparent window, is used in the fabrication. The biosensor is fabricated by using an UV-based soft imprint technique, which is considered to be cost-effective and suitable for mass production. By optimizing the volume ratio of Ormocore and the maT thinner, the device can be fabricated almost without a residual layer. The device works at a wavelength of 840 nm, where water absorption loss is much lower than at the infrared wavelengths. A two-step fitting method, including single-peak fitting and whole-envelope fitting, is applied in order to trace the spectral shift accurately. Finally, the two-cascaded-microrings biosensor is characterized, and the obtained FSR is 4.6 nm, which is 16 times larger than the FSR of the single microring biosensor demonstrated in our previous work. Moreover, the sensitivity can also be amplified by 16-fold, thanks to the Vernier effect.
关键词： Vernier effect,polymer waveguide,microring biosensor,nanoimprint
更新于2025-09-19 17:15:36
-
Wafer-scale HfO<sub>2</sub> encapsulated silicon nanowire field effect transistor for efficient label-free DNA hybridization detection in dry environment
摘要： Silicon nanowire (SiNW) charge based biosensors are attractive for DNA sensing applications due to their compactness and large surface-to-volume ratio. Small feature size, low production cost, repeatability, high sensitivity and selectivity are some of the key requirements for biosensors. The most common e-beam manufacturing method employed to manufacture sub-nm SiNWs is both cost and time intensive. Therefore, we propose a highly reproducible CMOS industry grade low-cost process to fabricate SiNW based field effect transistors on 4”-wafers. The 60 nm wide SiNWs reported in this paper are fabricated using the sidewall transfer lithography process which is a self-aligned-double-patterning I-line lithography process that also facilitates encapsulation of the SiNW surface with a thin HfO2 layer on which DNA probes are grafted to finalize the biosensors. Upon DNA hybridization, SiNW devices exhibit threshold voltage shift larger than the noise introduced by the exposition to saline solutions used for the bioprocesses. More specifically, based on a statistical analysis, we demonstrate that 85% of the tested devices exhibit a positive threshold voltage shift after DNA hybridization. These promising results make way for the monolithic integration of SiNW biosensors and CMOS circuitry to realize a point of care device which can offer reliable real time electrical readout.
关键词： HfO2 passivation,silicon nanowire hybridization,silicon nanowire,DNA sensing,pattern transfer lithography,biosensor
更新于2025-09-19 17:15:36
-
Wearable-band Type Visible-Near Infrared Optical Biosensor for Non-invasive Blood Glucose Monitoring
摘要： Diabetes is a worldwide-serious problem that can only be delayed or prevented by a regular monitoring of blood glucose (BG) concentration level. Continuous monitoring systems allow subjects to prepare the diabetes management strategy and prevent the long-term complications diseases. Until now, most studies utilize various biofluids such as sweat, tears and saliva that have serious unresolved setback such as expensive material, sensor stability, sensor calibration and long-settling time. Therefore, we developed a novel BG sensor which is cost efficient and highly wearable with a small data acquisition time window that allow a non-invasive, long-term continuous blood glucose monitoring (CGM) system. The novel biosensor exploits a unique information of the pulsatile to continuous components of the arterial blood volume pulsation during the change of blood glucose (BG) concentration at the wrist tissue. The reflected optical signal was measured in the combine visible-near infrared (Vis-NIR) spectroscopy. An in-vivo experiment which enclosed 12 volunteers in a two-hour modified carbohydrate-rich meals reached the average correlation coefficient (????) between the estimated and reference BG concentration of 0.86, with the standard prediction error (SPE) of 6.16 mg/dl. Moreover, the full-day experiment was also conducted to test the reliability of the proposed sensor. Results showed that the created model in the previous day, may estimate a full-day BG concentration which was done in next day with an adequate performance.
关键词： Wearable Sensor,Optical Biosensor,Noninvasive Measurement,Visible-Near Infrared Spectroscopy,Diabetes,Continuous Blood Glucose Monitoring
更新于2025-09-19 17:15:36
-
Spectral Interrogation based SPR Sensor for Blood Glucose Detection with Improved Sensitivity and Stability
摘要： A sensor chip for specific detection of blood glucose was developed. The sensor utilized a surface-plasmon-resonance (SPR) setup on a prism based Kretschmann configuration utilizing spectral interrogation scheme. Self-assembled monolayers (SAMs) based preparation provided the chip stability due to covalent bonds and hence it can be reused for multiple times. Such a scheme can be advantageous in continuous monitoring of blood glucose, without changing the chip. Control experiments were performed without molecular recognition layer to confirm the performance of the sensor. Furthermore, the measurements were performed on blood serums and compared with that of a conventional glucometer. The present sensor has the advantages of improved sensitivity (0.14 nm/(mg/dl)) and stable response for 3 months, which are better compared to existing reports.
关键词： Blood glucose,Self assembled monolayers,Surface plasmon resonance,Biosensor
更新于2025-09-19 17:15:36