Kaiqi Su

A cardiomyocyte-based biosensor for antiarrhythmic drug evaluation by simultaneously monitoring cell growth and beating.

Drug-induced cardiotoxicity greatly endangers the human health and results in resource waste. Also, it is a leading attribution to drug withdrawal and late-stage attrition in pharmaceutical industry. In the study, a dual function cardiomyocyte-based biosensor was introduced for rapid drug evaluation with xCELLigence RTCA Cardio system. The cardiomyocyte-based biosensor can monitor the cardiomyocyte growth and beating status simultaneously under the drug effects. Two typical cardiovascular drug, verapamil and flecainide were selected as treatment agents to test the performance of this biosensor. The experiment results showed that the performance of cardiomyocyte-based biosensor verified the basic drug effects by beating status and also tested the drug cytotoxicity by the cell index curves of cardiomyocyte growth. Based on the advanced sensor detection technology and cell culture technology, this cardiomyocyte-based biosensor will be a utility platform for the drug preclinical assessment.

High-performance beating pattern function of human induced pluripotent stem cell-derived cardiomyocyte-based biosensors for hERG inhibition recognition

High-throughput and high clinical relevance methods are demanded to predict the drug-induced cardiotoxicity in pharmaceutical and biotechnology industries to effectively decrease late-stage drug attrition. In this study, human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) were integrated into an interdigital impedance sensor array to fabricate a high performance iPSC-CM-based biosensor array with high-throughput and high-consistency beating pattern. Typical withdrawal approved drugs (astemizole, sertindole, cisapride, and droperidol) with hERG inhibition and positive control E-4031 were employed to determine the beating pattern function. From the results, it can be concluded that this iPSC-CM-based biosensor array can specifically differentiate the hERG inhibitors from the non-hERG inhibition compounds through beating pattern function.

An improved sensitive assay for the detection of PSP toxins with neuroblastoma cell-based impedance biosensor

Paralytic shellfish poisoning (PSP) toxins are well-known sodium channel-blocking marine toxins, which block the conduction of nerve impulses and lead to a series of neurological disorders symptoms. However, PSP toxins can inhibit the cytotoxicity effect of compounds (e.g., ouabain and veratridine). Under the treatment of ouabain and veratridine, neuroblastoma cell will swell and die gradually, since veratridine causes the persistent inflow of Na(+) and ouabain inhibits the activity of Na(+)/K(+)-ATPases. Therefore, PSP toxins with antagonism effect can raise the chance of cell survival by blocking inflow of Na(+). Based on the antagonism effect of PSP toxins, we designed an improved cell-based assay to detect PSP toxins using a neuroblastoma cell-based impedance biosensor. The results demonstrated that this biosensor showed high sensitivity and good specificity for saxitoxins detection. The detection limit of this biosensor was as low as 0.03 ng/ml, which was lower than previous reported cell-based assays and mouse bioassays. With the improvement of biosensor performance, the neuroblastoma cell-based impedance biosensor has great potential to be a universal PSP screening method.

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.

Detection and classification of natural odors with an in vivo bioelectronic nose.

The mammalian olfactory system is recognized as one of the most effective chemosensing systems. We thus investigated the potential of utilizing the rats olfactory system to detect odors. By chronically coupling multiple microelectrodes to olfactory bulb of behaving rats, we extract an array of mitral/tufted cells (M/Ts) which could generate odor-specific temporal patterns of neural discharge. We performed multidimensional analysis of recorded M/Ts, finding that natural odors released from different fruit lead to distinct odor response patterns. Thus an array of M/Ts carried sufficient information to discriminate odors. This novel brain-machine interface using rats olfaction presents a promising method for odor detection and discrimination, and it is the first step towards in vivo bioelectronic nose equipped with biological olfaction and artificial devices.

An integrated label-free cell-based biosensor for simultaneously monitoring of cellular physiology multiparameter in vitro.

The study presented a novel integrated cell-based biosensor with light-addressable potentiometric sensor (LAPS) and electrical cell-substrate impedance sensor (ECIS). The integrated cell-based biosensor was fabricated in order to monitor the cellular metabolism and growth status by LAPS and ECIS. Moreover, the specific instrument was established for controlling the detection processes. Sensor test and cell experiments were carried out to determine the performance of integrated sensor. The result showed that integrated biosensor can monitor the change of cell electrical impedance and extracellular acidification simultaneously which can be used for drug evaluation by monitoring cell growth status (e.g. cell number, adhesion, and morphology) and cell energy metabolism status (e.g. extracellular acidification) in real time. With the development of sensor technology, the integrated cell-based biosensor will be a utility platform to study the mechanism of cellular metabolism and in vitro drug analysis.

A sensing smartphone and its portable accessory for on-site rapid biochemical detection of marine toxins

Okadaic acid (OA) and saxitoxin (STX) are common marine toxins which can accumulate in shellfish and affect human health through the food chain. A convenient and efficient method is urgently required to perform on-site detection of marine toxins to avoid frequent poisoning incidents. In this work, a smartphone-based system cooperating with competitive immunoassay strips was designed for rapid on-site detection of OA and STX. The smartphone was employed as a light detector for image acquisition and data processing. The 3D-printed portable accessory of the smartphone was utilized to fix the test strips. The homemade APP – iStrip used the pixel scan to obtain the valley value of the pixel curve as the output of the strip. The strip analytical method was easy to operate with a detection limit of 2.800 ng ml−1 for OA and 9.808 ng ml−1 for STX. Moreover, with the optimization of the antigen–antibody ratio on the strip, it provided quantitative analysis of OA and STX in the range of 3–20 ng ml−1 and 10–100 ng ml−1, respectively. Taking advantage of the smartphone and biochemical analysis, the strip analytical system will be a promising tool for on-site rapid detection of these two toxins.

Detection of 5-hydroxytryptamine (5-HT) in vitro using a hippocampal neuronal network-based biosensor with extracellular potential analysis of neurons

5-hydroxytryptamine (5-HT) is an important neurotransmitter in regulating emotions and related behaviors in mammals. To detect and monitor the 5-HT, effective and convenient methods are demanded in investigation of neuronal network. In this study, hippocampal neuronal networks (HNNs) endogenously expressing 5-HT receptors were employed as sensing elements to build an in vitro neuronal network-based biosensor. The electrophysiological characteristics were analyzed in both neuron and network levels. The firing rates and amplitudes were derived from signal to determine the biosensor response characteristics. The experimental results demonstrate a dose-dependent inhibitory effect of 5-HT on hippocampal neuron activities, indicating the effectiveness of this hybrid biosensor in detecting 5-HT with a response range from 0.01μmol/L to 10μmol/L. In addition, the cross-correlation analysis of HNNs activities suggests 5-HT could weaken HNN connectivity reversibly, providing more specificity of this biosensor in detecting 5-HT. Moreover, 5-HT induced spatiotemporal firing pattern alterations could be monitored in neuron and network levels simultaneously by this hybrid biosensor in a convenient and direct way. With those merits, this neuronal network-based biosensor will be promising to be a valuable and utility platform for the study of neurotransmitter in vitro.

Detection of cardiovascular drugs and marine toxins using a multifunctional cell-based impedance biosensor system

With growing concern about human health, relevant drug and food toxicity has drawn more and more attention. However, traditional methods like mouse bioassays cannot meet the sharply increasing demand for drug and food toxicity assessment. In this study, a multifunctional cell-based impedance biosensor system is established for drug and toxin analysis, using a cell-based impedance biosensor (CIB) as the sensitive element. Cellular growth and beating experiments were carried out to verify the multifunctionality of the system. Four typical heart-related compounds including verapamil, bay K8644, chromanol 293B, and adriamycin were used for cardiotoxicity analysis function tests of the CIB system. Also, one typical marine diarrhetic toxin, okadaic acid (OA), was used for cytotoxicity analysis function tests of the CIB system. From the results, the CIB system can reflect the drug function and toxicity directly through the cell growth and beating status. According to the results, the multifunctional CIB system may provide a high-throughput and useful method for effective screening of cardiovascular drugs and marine toxins in vitro.

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.