The self-made high sensitivity and selectivity micro-biosensor was applied to monitor the change of dopamine in cerebral nucleus in rats in vivo. The micro-biosensor was prepared and used to detect dopamine level in vitro and monitor the dynamic change of dopamine in different cerebral nucleus in vivo. The results showed the lowest concentration of dopamine that could be detected by the biosensor was 32.5 nmol/L. Its positive peak was significantly different from that of AA, 5-HTP and E. The biosensor could keep working for monitoring the dopamine concentration in the cerebral tissue for more than 10 h. It was concluded that the microsensor has high sensitivity and selectivity to dopamine and can be used to dynamically monitor the change of dopamine in vivo.
Biosensing Techniques/*instrumentation ; Biosensing Techniques/methods ; Brain Chemistry ; Corpus Striatum/*metabolism ; Dopamine/*analysis ; Microelectrodes ; Monitoring, Physiologic

To overcome the present limitations of passive biochip, based on the basic principle of antigen-antibody reaction, we develop an antigen-antibody reaction model of solid-phase surface and design a novel active biochip system according to this model, which introduces the negative pressure and controlling devices to control the immunoreactions on the nitrocellulose (NC) membrane. From the computer simulation results, this is a rapid, stable, robust and practicable system, which can be used to increase the efficiency of immunoreactions and improve the reproducibility and accuracy of biochip analysis.
Antigen-Antibody Reactions ; Biosensing Techniques ; instrumentation ; Equipment Design ; Models, Biological

A stable, uniform, easily implemented, LC-based chemical and biological sensor substrate for orientations of liquid crystals (LCs) for a long-term is urgently needed for medical applications of the sensors. We proposed a use of spin-coating of copper perchlorate (Cu(ClO4)2), with five different concentrations(0-100mmol/L), directly on glass slides for fabricating a layer of chemically-sensitive copper ions. Observing the transmitted light with a polarized microscope, we found the luminosity of the light propagated through sensors deposited with copper ions started to weaken gradually after a certain time. The higher was the concentration of copper ions covered on the glass substrates of the sensors, the faster the weakening occurred, and the less time was needed for transmitted light to turn completely dark. But there was no change in luminosity of the transmitted light for the sensors without Cu(ClO4)2 spin-coating even after stored at room temperature (25 degrees C) for a whole day. When the Cu(ClO4)2 deposited sensors were stored within a drying oven at room temperature (25 degrees C) for 2 months, it was found that there vas almost no change in luminosity of the transmitted lights. The results showed that all the thin films of LC on glass slides functionalized with Cu(ClO4)2 could keep homeotropic and stable orientation for a long time; the concentration of Cu (ClO4)2I has an influence on the orientation response speed of LC from planar to perpendicular orientation.
Biosensing Techniques ; instrumentation ; Copper ; chemistry ; Glass ; chemistry ; Liquid Crystals ; chemistry

Endotoxin is an important factor which can lead to endotoxemia and complication. Accurate detection of its concentration is very useful for the diagnosis and treatment of these diseases. A piezoelectric biosensor for detecting endotoxin was developed, which was based on liquid damping effect of quartz crystal resonator. The test results showed that the maximal frequency shift of sensor is linearly dependent on the logarithm value of concentration of endotoxin (0.1 pg/m - 10 ng/ml). The time which d (deltaf)/dt(maax) appeared in frequency shift curve was also linearly dependent on the logarithm value of concentration of endotoxin (0.01 pg/ml - 10 ng/ml). The detection time was shortened and the minimal limit of detection was decreased using the second method. Thus the proposed sensor is much simpler, more precise and has more lower limit of detecting detection of endotoxin when compared with the conventional methods.
Animals ; Biosensing Techniques ; instrumentation ; Endotoxins ; analysis ; Equipment Design ; Quartz ; Rabbits

Biosensing Techniques ; instrumentation ; trends ; DNA ; analysis ; chemistry ; Humans

Neurotransmitters play an important role in nervous system. Temporal and spatial changes of neurotransmitter distribution are crucial to information processing in neural networks. Biosensors that can visually monitor neurotransmitters are one of the vital tools to explore a variety of physiological and pathological activities. This article reviews recent advances in monitoring neurotransmitters with high temporal and spatial resolution, and introduces the latest fluorescent imaging methods for typical neurotransmitters, including glutamate, dopamine, γ-aminobutyric acid and acetylcholine. The article also summarizes the basic principles, advantages and disadvantages of various visually detection methods, and provides systematic suggestions for designing neurotransmitter sensors with high temporal and spatial resolution.
Animals ; Biosensing Techniques ; instrumentation ; trends ; Fluorescence ; Humans ; Neurotransmitter Agents ; metabolism

This article summarizes biological detection techniques based on magnetic signal of magnetic nanoparticles and the research progress of these techniques in biomedicine. Biological detection based on magnetic nanoparticles is faster, more accurate and more convenient compared to traditional optical techniques and causes much attention. It can be classified into giant magneto resistive biosensor (GMR), magnetic relaxation switch (based on T2 relaxation time), AC susceptibility (based on Brownian relaxation) and magnetic lateral flow immunoassay. These techniques can be combined with nanotechnology, microfluidics, immunoassay and bio-chips and have wide application prospects in clinical diagnosis, biological detection, environmental monitoring and food security areas.
Biosensing Techniques ; instrumentation ; methods ; Immunoassay ; instrumentation ; methods ; Magnetic Phenomena ; Nanoparticles ; chemistry ; Nanotechnology ; instrumentation ; Point-of-Care Systems

This paper introduces the design of traditional photoelectric pulse sensor, researches the measure noise and realizes the improvement of the sensor. Laser diode is used instead of traditional LED to improve the quality of the light source. The circuit is designed based on double OPT101,and the signal detection circuit is improved. Data communication is proposed based on nRF24E1 and data wireless communication is realized. The test results indicate that the system can efficiently remove the system noise and improve the precision of measure.
Biosensing Techniques ; instrumentation ; Computer Communication Networks ; instrumentation ; Equipment Design ; Signal Processing, Computer-Assisted ; instrumentation

OBJECTIVETo improve the key technology of immunesensors in immobilizing bio-sensitive element and keeping its bioactivity, an enzyme immunosensor based on chitosan-SiO(2) (CS-Sio(2)) hybrid membrane was fabricated. To estimate the new immunosensor Vibrio parahaemolyticus which was the main pathogens of aquatic products.

METHODSA CS-SiO(2) hybrid membrane was prepared using sol-gel method. The enzyme immunosensor was fabricated by coating the membrane and horseradish peroxidase labeled Vibrio parahaemolyticus antibody (HRP-anti-VP) on the surface of four-channel screen-printed carbon electrode. The immunosensor was characterized by cyclic voltammetry. Vibrio parahaemolyticus could be detected according to the decrease percentage (DP) of peak current before and after immune response, while cyclic voltammetry was used as an electrochemical mean to detect the products of the enzymatic reaction. Seven kinds of bacteria, like Vibrio alginolyticus, were selected for specific experiments.

RESULTSBy studying the infrared spectrum of three kinds of films, the CS-SiO(2) hybrid membrane was prepared and HRP-anti-VP was fixed in the hybrid membrane. Under the optimum conditions of immunoreaction and electrochemical detection, the DP of peak current before and after immune response showed a linear relation with lgC in the range of 10(4) - 10(9) cfu/ml, while the linear regression equation was: DP = 6.5 lgC-3.319, the correlation coefficient was 0.9958 and the detection limit was 6.9 x 10(3) cfu/ml (S/N = 3). The immunosensor possessed acceptable specificity, reproducibility (RSD < 6%), stability (the amperometric response was 95% of the initial response after a week) and accuracy (96.7% of the results obtained by the immunosensor were in agreement with those obtained by GB/T 4789.7-2003).

CONCLUSIONThe enzyme immunosensor based on CS-SiO(2) hybrid membrane gave a good performance in rapid detection of Vibrio parahaemolyticus.

Biosensing Techniques ; instrumentation ; methods ; Electrochemical Techniques ; instrumentation ; methods ; Equipment Design ; Immunoenzyme Techniques ; instrumentation ; methods ; Silicon Dioxide ; Vibrio parahaemolyticus ; isolation & purification

Wearable monitoring technology is a hot spot in biomedical engineering and military medical devices. This paper reviews the research progress about the wearable life-sign monitoring system for a single soldier.
Biosensing Techniques ; instrumentation ; Clothing ; Equipment Design ; Military Medicine ; instrumentation ; Monitoring, Ambulatory ; instrumentation ; Radio ; instrumentation ; Telemetry ; instrumentation ; Textiles