No abstract available.
Biosensing Techniques ; Urinary Bladder

Background: DNA biosensor is based on micro-nano technologies aimed at developing a rapid diagnostic device of infectious diseases and diseases related to genetic change. Biosensors are compact size, high sensitivity and low cost\r\n', u'Objectives: To evaluate effect of biosensor in detecting specific gene fragments of Herpes Simplex virus type 1 and 2 (HSV)\r\n', u'Subjects and method: The electrical signals were recognized by means of transducer and from electrochemical detection of the hybridization between the probe 5\ufffd?AT CAC CGA CCC GGA GAG GGA C-3\ufffd?which were covalently immobilised onto the surface of micro electrodessensors in 3-aminopropyltri-ethoxysilance (APTS)-the conducting polymer matrix and the target (specific DNA sequences of HSV in the sample.\r\n', u'Results: The DNA sensor offers a very high sensitivity, a fast response time, less than 1 min with the DNA target concentration up to 1nM in aqueous media at room temperature.However, in order to detect target DNA in the real samples, samples must be extracted DNA, denatured DNA sequences from a double fiber to single fiber. The measurement should be done soon\r\n', u'Conclusion: The results show a large promise to develop quickly DNA sensors for widely application in bio-medical research \r\n', u'\r\n', u'
Biosensing Techniques ; CNBP protein ; human ;

An enzyme electrode biosensor was used for the amperometric determination of inosine in its tablets by co-immobilizing nucleoside phosporylase and xanthine oxidase on a hydrogen peroxide electrode. As a fundamental electrode the hydrogen peroxide electrode has an advantage of stability in analysis compared with the 02 electrode. The enzyme electrode showed a linear response to inosine in the range of 1-268 mg/L with a response of 60 seconds under a sample injection volume of 25 microL. Based on the enzyme electrode, inosine solutions were determined with an average recover rate of 100.8% and a relative standard deviation (RSD) of les than 0.14% in 20 assays. The lifetime of the enzyme electrode was relative long and could be used continuously at 25 degrees C for 25 days. These results demonstrated that the enzyme electrode biosensor could be used to determine inosine and its derivatives specifically, rapidly, conveniently and economically.
Biosensing Techniques ; methods ; Inosine ; analysis ; Sensitivity and Specificity

As the main factor leading to foodborne illnesses, foodborne pathogens have been attached great importance by people. The development of simple, rapid, high-sensitivity and low-cost food-borne pathogen detection methods is of great significance in reducing the incidence of foodborne diseases. Biosensor technology is a new micro-analysis technology developed by multi-disciplinary cross-infiltration. It has the characteristics of high sensitivity and fast analysis speed, and is widely used in the detection of food-borne pathogens. This paper introduces the basic principles of biosensors, summarizes the application of common biosensors in the detection of foodborne pathogens, and prospects for future development.
Biosensing Techniques ; Food Microbiology ; Foodborne Diseases ; Humans

Synthetic biology aims to endow living cells with new functions by incorporating functional gene networks into them. By overexpressing, blocking and rewiring native gene pathways, synthetic biologists have harnessed this promising technology to reprogram cells to perform diverse tasks such as drug discovery, biopharmaceutical manufacturing, gene therapy and tissue engineering, etc. In this review, we focus on current technologies of synthetic biosensors for disease detection. We start with the design principle of synthetic biosensors. Then we move towards the characteristics of simple synthetic biosensors, which can respond to a single input signal, and complex synthetic biosensors including Boolean gate biosensors, cascade biosensors, time-delay biosensors, oscillator biosensors and hysteretic biosensors, which can respond to more than two input signals and perform complex tasks. Synthetic biosensor has showed great potential in disease detection, but it is still in its infancy stage. More efforts should be made in identifying and constructing clinically relevant regulation systems. Computational tools are also needed in the design process in order to guarantee the precision of the synthetic biosensor. The ultimate goal of a synthetic biosensor is to act as a therapeutic sensor-effector device that connects diagnostic input with therapeutic output and therefore provides all-in-one diagnostic and therapeutic solutions for future gene- and cell-based therapies.
Biosensing Techniques ; methods ; Humans ; Synthetic Biology ; methods

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

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

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

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

OBJECTIVETo establish a highly sensitive fluorometric nanobiosensor for determination of aqueous mercury ions (Hg(2+)) using optimized mercury-specific oligonucleotide (MSO) probes and graphene oxide (GO).

METHODSThe nanobiosensor was assembled by attaching the self-designed MSO(1) (5' end labeled with fluorophore carboxyfluorescein (FAM), denoted as FAM-MSO(1)) and MSO(2) to the surface of GO through strong non-covalent bonding forces. Upon the addition of Hg(2+), the formation of the T-Hg(2+)-T configuration desorbed the FAM-MSO(1) and MSO(2) from the surface of GO, resulting in a restoration of the fluorescence of FAM-MSO(1). Using the specific mispairing of T-Hg(2+)-T and the changes in fluorescent signals in solutions, quantitative analysis of Hg(2+) could be performed.

RESULTSThe average thickness of the prepared GO sheets was only 1.4 nm. For the Hg(2+) nanobiosensor, the optimum concentrations of FAM-MSO(1) and MSO(2) were both 1 µmol/L, the optimum volume of 0.5 g/L GO was 5 µL, and the limit of detection was 10 pmol/L; it had low cross-reactivity with 10 other kinds of non-specific metal ions; the fluorescence recovery efficiency was up to 65% in the re-determination of Hg(2+) after addition of Na(2)S(2)O(3).

CONCLUSIONThe MSO/GO-based nanobiosensor is convenient to operate, highly sensitive, highly specific, highly accurate, and reusable. It can be applied to determine trace amount of Hg(2+) in aqueous solutions.