Jiaru Fang

An improved functional assay for rapid detection of marine toxins, saxitoxin and brevetoxin using a portable cardiomyocyte-based potential biosensor

Saxitoxin (STX) and brevetoxin (PbTX-2), which are produced by marine dinoflagellates, are highly-toxic marine toxins targeting separate sites of the α subunit of voltage-dependent sodium channels (VDSCs). In this work, a portable cardiomyocyte-based potential biosensor is designed for rapid detection of STX and PbTX-2. This potential biosensor is constructed by cardiomyocyte and microelectrode array (MEA) with a label-free and real-time wireless 8-channel recording system which can dynamically monitor the multisite electrical activity of cardiomyocyte network. The recording signal parameters, spike amplitude, firing rate and 50% of spike potential duration (SPD50) extracted from extracelluar field potential (EFP) signals of the potential biosensor is analyzed to quantitatively evaluate toxicological risk of STX and PbTX-2. Firing rate of biosensor signals presents high sensitivity to STX with the detection limit of 0.35 ng/ml within 5 min. SPD50 shows high sensitivity to PbTX-2 with the detection limit of 1.55 ng/ml within 5 min. Based on the multi-parameter analysis, cardiomyocyte-based potential biosensor will be a promising tool for rapid detection of these two toxins.

A novel sensitive cell-based Love Wave biosensor for marine toxin detection

A novel HepG2 cell-based biosensor using Love Wave sensor was developed to implement the real-time and sensitive detection of a diarrheic shellfish poisoning (DSP) toxin, Okadaic acid (OA). Detachable Love Wave sensor unit and miniaturized 8-channel recording instrument were designed for the convenient experimental preparation and sensor response signal measurement. The Love Wave sensor, whose synchronous frequency is around 160 MHz, was fabricated with ST-cut quartz substrate. To establish a cell-based biosensor, HepG2 cells as sensing elements were cultured onto the Love Wave sensor surface, and the cell attachment process was recorded by this biosensor. Results showed this sensor could monitor the cell attachment process in real time and response signals were related to the initial cell seeding densities. Furthermore, cell-based Love Wave sensor was treated with OA toxin. This biosensor presented a good performance to various OA concentrations, with a wide linear detection range (10-100 μg/L). Based on the ultrasensitive acoustic wave platform, this cell-based biosensor will be a promising tool for real-time and convenient OA screening.

High-efficient and high-content cytotoxic recording via dynamic and continuous cell-based impedance biosensor technology

Cell-based bioassays were effective method to assess the compound toxicity by cell viability, and the traditional label-based methods missed much information of cell growth due to endpoint detection, while the higher throughputs were demanded to obtain dynamic information. Cell-based biosensor methods can dynamically and continuously monitor with cell viability, however, the dynamic information was often ignored or seldom utilized in the toxin and drug assessment. Here, we reported a high-efficient and high-content cytotoxic recording method via dynamic and continuous cell-based impedance biosensor technology. The dynamic cell viability, inhibition ratio and growth rate were derived from the dynamic response curves from the cell-based impedance biosensor. The results showed that the biosensors has the dose-dependent manners to diarrhetic shellfish toxin, okadiac acid based on the analysis of the dynamic cell viability and cell growth status. Moreover, the throughputs of dynamic cytotoxicity were compared between cell-based biosensor methods and label-based endpoint methods. This cell-based impedance biosensor can provide a flexible, cost and label-efficient platform of cell viability assessment in the shellfish toxin screening fields.

Dual-function microelectrode array system for simultaneously monitoring electromechanical integration status of cardiomyocytes

In this study, a novel dual-functional cardiomyocyte-based biosensor system is developed based on microelectrode array (MEA). Primary neonatal Sprague-Dawley (SD) rat cardiomyocytes and MEA are employed in constructing the cardiomyocyte-based biosensor. Besides, the impedance detection function of MEA is explored to monitor the rhythmic beating of cardiomyocytes, while the extracellular potential is simultaneously recorded by MEA. Combined both functions, electric excitation and mechanical beating signals can be detected on one sensor chip. Also, dual-functional MEA system is established. Based on this electromechanical integration detection function, dual-functional cardiomyocyte-based biosensor system will be a utility platform for cellular physiological study and drug assessment.

A novel Love Wave biosensor for rapid and sensitive detection of marine toxins

Marine toxins are produced by plankton and do a great harm to human through food chain by accumulating in shellfishes and fishes. It is highly required and favorable to develop novel methods for the rapid and efficient detection of marine toxins to avoid the poisoning cases that have occurred frequently in many countries. This study presents a real-time Love Wave biosensor for the rapid detection of okadaic acid (OA), which used HepG2 cell lines as the sensing elements. The results indicate that this cell-based biosensor can provide real-time information of cellular activities induced by okadaic acid and has a higher sensitivity than the conventional cell-based assay. It is suggested that this cell-based biosensor can be used as a convenient and efficient method for marine toxin detection, which has a great potential to contribute to avoid the harmful effects of marine toxins on the human health.

Micro/Nano Biosensors for Living Cell and Molecule Analysis

The novel micro/nano cell and molecule biosensors are developed based on the traditional microfabrication and novel nanotechnology. Traditional biosensors, such as microelectrode array, impedance sensor, field-effect transistor, and light addressable potentiometric sensor, are useful tools in studying the cell biology and molecule analysis, while the nanobiosensor- and nanomaterial modified biosensors emerge gradually with the advance of nanotechnology. These nanobiosensor can achieve the single cell monitoring with high-quality signals, and nanomaterial modified biosensors have demonstrated excellent performance in cell and molecule applications. Combination of sensor detection technology and nanotechnology, the novel micro/nano cell, and molecule biosensors can explore a wide way in fields of biomedicine and environment monitoring.

Micro/Nano Cell Potential Biosensors

As a novel functional bioanalytical method, the cell sensor has become one of the hotspots in the field of biosensors. A cell sensor with high sensitivity can make a quick response to external stimuli, and it has good stability and biocompatibility, is nondestructive, and is used for long-time dynamic monitoring for physiological parameters of different types of cells. In general, a cell sensor can relatively easily achieve miniaturization including batch processing, thereby reducing costs. With the development of microelectromechanical systems technology, the technical means to detect extracellular action potentials emerges, such as microelectrode array (MEA) cell potential sensors. MEA is a commonly used method to detect extracellular action potentials that not only can analyze the electrical activity of electrical excitable cells, but can achieve pharmacology and toxicology analysis of different drugs or toxins. This chapter study further improves the method of the cardiomyocyte and sensor chip coupling, and successfully builds a high stability and consistency of a cardiomyocyte potential sensor. It can explain cell sensor availability that uses a cardiomyocyte sensor for drug analysis and to detect toxins in food, thus by taking advantage of the characteristics, the cell sensor can develop a new testing technology in the food field that has great application prospects in detection analysis.