- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Designing bacterial chemotactic receptors guided by photonic femtoliter well arrays for quantifiable, label-free measurement of bacterial chemotaxis
摘要： Whole cell bioreporters, such as bacterial cells, can be used for environmental and clinical sensing of specific analytes. However, the current methods implemented to observe such bioreporters in the form of chemotactic responses heavily rely on microscope analysis, fluorescent labels, and hard-to-scale microfluidic devices. Herein, we demonstrate that chemotaxis can be detected within minutes using intrinsic optical measurements of silicon femtoliter well arrays (FMAs). This is done via phase-shift reflectometric interference spectroscopic measurements (PRISM) of the wells, which act as silicon diffraction gratings, enabling label-free, real-time quantification of the number of trapped bacteria cells in the optical readout. By generating unsteady chemical gradients over the wells, we first demonstrate that chemotaxis towards attractants and away from repellents can be easily differentiated based on the signal response of PRISM. The lowest concentration of chemorepellent to elicit an observed bacterial response was 50 mM, while the lowest concentration of chemoattractant to elicit a response was 10 mM. Second, we employed PRISM, in combination with a computational approach, to rapidly scan for and identify a novel synthetic histamine chemoreceptor strain. Consequently, we show that by using a combined computational design approach, together with a quantitative, real-time, and label-free detection method, it is possible to manufacture and characterize novel synthetic chemoreceptors in Escherichia coli (E. coli).
关键词： diffraction,synthetic biology,optical biosensor,chemotaxis,microstructures
更新于2025-09-23 15:23:52
-
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
-
OPTICAL BIOSENSORS PROSPECTIVE BASED ON BRAGG GRATING POLYMER WAVEGUIDE
摘要： In this work, we demonstrate the potential of Bragg grating polymer waveguide as an optical biosensor. Visible wavelength region at 650 nm is used as a centre wavelength because it is commonly used in biological and chemical sensing for both label and label-free sensing. The Bragg polymer waveguide structure is simulated using RSoft optical design and analysis software. The results show that there is a transmission drop with a 3 dB bandwidth of 661.0 nm when the surrounding refractive index is 1.33. The specific wavelength (transmission drop) is shifted to 724.2 nm when we increased the surrounding medium into 1.43 to mimic the bioanalytes solution. Simulation result shows that the wavelength shift was approximately 63.2 nm for every 0.1 increasing of surrounding refractive index. The Bragg grating polymer waveguide was fabricated by using electron beam lithography. Then, the fabricated devices were easily integrated within microfluidic systems in order to validate the wavelength shift. From the experiments, the wavelength shift occurred approximately 20.3 nm over 0.1 increment of refractive index. The discrepancies were likely due to the accumulation of sucrose solution on top and sidewall of the sensing area, the insertion loss between input and output coupling of the waveguide interface that induced the noise to signal ratio. Where we know that, is impossible to happen in simulation. Thus both simulation and experimental results strongly indicate that Bragg grating polymer waveguide structure at visible wavelength region have a potential for label or label-free optical biosensing applications.
关键词： simulation,label-free sensing,polymer waveguide,Optical biosensor,Bragg grating
更新于2025-09-19 17:13:59
-
Quantification of Neuropeptide Y with Picomolar Sensitivity Enabled by Guided-Mode Resonance Biosensors
摘要： Assessing levels of neuropeptide Y (NPY) in the human body has many medical uses. Accordingly, we report the quantitative detection of NPY biomarkers applying guided-mode resonance (GMR) biosensor methodology. The label-free sensor operates in the near-infrared spectral region exhibiting distinctive resonance signatures. The interaction of NPY with bioselective molecules on the sensor surface causes spectral shifts that directly identify the binding event without additional processing. In the experiments described here, NPY antibodies are attached to the sensor surface to impart speci?city during operation. For the low concentrations of NPY of interest, we apply a sandwich NPY assay in which the sensor-linked anti-NPY molecule binds with NPY that subsequently binds with anti-NPY to close the sandwich. The sandwich assay achieves a detection limit of ~0.1 pM NPY. The photonic sensor methodology applied here enables expeditious high-throughput data acquisition with high sensitivity and speci?city. The entire bioreaction is recorded as a function of time, in contrast to label-based methods with single-point detection. The convenient methodology and results reported are signi?cant, as the NPY detection range of 0.1–10 pM demonstrated is useful in important medical circumstances.
关键词： neuropeptide Y,guided-mode resonance biosensor,biomarkers,sandwich assay,optical biosensor
更新于2025-09-12 10:27:22