Electrode Chip Research Articles

Bio-Compatibility and Bio-Insulation of Implantable Electrode Prosthesis Ameliorated by A-174 Silane Primed Parylene-C Deposited Embedment.

Microelectrodes for pain management, neural prosthesis or assistances have a huge medical demand, such as the application of pain management chip or retinal prosthesis addressed on age-related macular degeneration (AMD) and the retinitis pigmentosa (RP). Due to lifelong implanted in human body and direct adhesion of neural tissues, the electrodes and associated insulation materials should possess an ideal bio-compatibility, including non-cytotoxicity and no safety concern elicited by immune responses. Our goal intended to develop retinal prosthesis, an electrical circuit chip used for assisting neural electrons transmission on retina and ameliorating the retinal disability. Therefore, based on the ISO 10993 guidance for implantable medical devices, the electrode prosthesis with insulation material has to conduct bio-compatibility assessment including cytotoxicity, hemolysis, (skin) irritation and pathological implantation examinations. In this study, we manufactured inter-digitated electrode (IDE) chips mimic the electrode prosthesis through photolithography. The titanium and platinum composites were deposited onto a silicon wafer to prepare an electric circuit to mimic the electrode used in retinal prosthesis manufacture, which further be encapsulated to examine the bio-compatibility in compliance with ISO 10993 and ASTM guidance specifically for implantable medical devices. Parylene-C, polyimide and silicon carbide were selected as materials for electrode encapsulation in comparison. Our data revealed parylene-C coating showed a significant excellence on bio-insulation and bio-compatibility specifically addressed on implantable neuron stimulatory devices and provided an economic procedure to package the electrode prosthesis. Therefore, parylene C encapsulation should serve as a consideration for future application on retinal prosthesis manufacture and examination.

Advances in Electrochemical Impedance Spectroscopy Detection of Endocrine Disruptors.

Endocrine disruptors (EDs) are contaminants that may mimic or interfere with the body’s hormones, hampering the normal functions of the endocrine system in humans and animals. These substances, either natural or man-made, are involved in development, breeding, and immunity, causing a wide range of diseases and disorders. The traditional detection methods such as enzyme linked immunosorbent assay (ELISA) and chromatography are still the golden techniques for EDs detection due to their high sensitivity, robustness, and accuracy. Nevertheless, they have the disadvantage of being expensive and time-consuming, requiring bulky equipment or skilled personnel. On the other hand, early stage detection of EDs on-the-field requires portable devices fulfilling the Affordable, Sensitive, Specific, User-friendly, Rapid and Robust, Equipment free, Deliverable to end users (ASSURED) norms. Electrochemical impedance spectroscopy (EIS)-based sensors can be easily implemented in fully automated, sample-to-answer devices by integrating electrodes in microfluidic chips. The latest achievements on EIS-based sensors are discussed and critically assessed.

Intracellular Metal-Organic Frameworks: Integrating an All-In-One Semiconductor Electrode Chip for Therapy, Capture, and Quantification of Circulating Tumor Cells.

Capture, analysis, and inactivation of circulating tumor cells (CTCs) have emerged as important issues for the early diagnosis and therapy of cancer. In this study, an all-in-one sensing device was developed by integrating magnetic metal-organic framework (magMOF) nanoparticles (NPs) and TiO2 nanotube arrays (TiNTs). The magMOF NPs are composed of a magnetic Fe3O4 core and a MIL-100(Fe) shell, which is loaded with glucose oxidase (GOD) and provides an intensive starvation therapy by catalyzing the consumption of cellular nutrients, thus accelerating the generation of intracellular iron ions by MIL-100(Fe) dissolution. Importantly, these iron ions not only lead to an intensive Fenton-like reaction but also establish an excellent correlation of electrochemical intensities with cancer cell numbers. Owing to the intracellular magMOF NPs, the CTCs were magnetically collected onto TiNTs. The exogenous ·OH radicals generated by TiNT photocatalysis trigger iron ions to be rapidly released out and subsequently detected via differential pulse voltammetry using TiNTs as the electrode. An excellent correlation of differential pulse voltammetry intensities with CTC numbers is obtained from 2 to 5000 cell mL-1. This nanoplatform not only paves a way to combine starvation therapy agents with Fenton-like reaction for chemodynamic therapy but also opens up new insights into the construction of all-in-one chips for CTC capture and diagnosis.

Feasibility of a Novel Mobile C-Reactive Protein-Testing Device Using Gold-Linked Electrochemical Immunoassay: Clinical Performance Study.

BackgroundHome-based care is one of the most promising solutions to provide sufficient medical care for several older patients in Japan. However, because of insufficient diagnostic devices, it is sometimes difficult to detect early signs of the occurrence or worsening of diseases, such as infections under home-based care settings. C-reactive protein (CRP) is highly sensitive to diagnosing infections, and its elevation can help diagnose acute infection in older patients. Therefore, a CRP-measuring device that can be used in such a specific occasion is needed for home-based care. However, aspects such as its size, weight, and procedure are still challenging with respect to the practical use of mobile devices that quantitatively measure CRP levels easily and quickly under home-based care settings.ObjectiveWe developed a new mobile, rapid CRP measurement device using a gold-linked electrochemical immunoassay (GLEIA) system. The aim of this study was to evaluate the feasibility of this mobile CRP-testing device.MethodsFirst, we assessed the performance of bare GLEIA-based electrode chips as the foundation of the device. After embedding the bare GLEIA-based electrode chips in a special plastic case and developing the mobile CRP-testing device, we further tested the device prototype using clinical blood samples. Finally, we evaluated the intra-assay variability for precision in the same condition and inter-assay variability for reproducibility in different conditions.ResultsBlood samples for analysis were obtained by direct vein puncture from outpatients (N=85; females: 57/85; males: 28/85; age: 19-88 years) at Kanazawa University Hospital in Japan. For performance evaluation of bare GLEIA-based electrode chips, we used 85 clinical blood samples. There was a significant positive correlation between the electrode-predicted CRP levels and the reference CRP concentrations (R2=0.947; P<.001). The assembled device was mobile (size 45×90×2.4 mm; weight 10 g) and disposable. The minimum volume of the sample needed for measuring CRP was 1.4 µL. The estimated preanalytical time was approximately 7 minutes and 40 seconds, and analysis time was approximately 1 minute and 10 seconds. Subsequently, for performance evaluation of the mobile CRP-testing device using GLEIA-based electrode chips, we used 26 clinical blood samples and found a significant positive correlation between the mobile device-predicted CRP levels and the reference CRP concentrations (R2=0.866, P<.001). The intra-assay variabilities were 34.2%, 40.8%, and 24.5% for low, medium, and high CRP concentrations, respectively. The inter-assay variabilities were 46.5%, 38.3%, and 64.1% for low, medium, and high CRP concentrations, respectively.ConclusionsOur findings suggest that this new mobile CRP-testing device might be suitable for use in home-based care settings.

3D cell capture and sensing array electrode (3D ECCSA) under extremely low frequency electromagnetic fields (ELF-EMF)

Recently, many studies have shown that extremely low frequency electromagnetic fields (ELF-EMF) may lead to enhanced cell proliferation and inhibit the growth of specific cancer cells. In this study, 3D cell-based biosensors and an ELF-EMF device are integrated for real-time, non-invasive monitoring of single cell culture and measurement under ELF-EMF. MDA-MB-231 cells are cultured in a three-dimensional cell capture and sensing array electrode (3D ECCSA) chip under different intensities of ELF-EMF. A single cell is captured in the electrode for long-term impedance measurement (12 h). In this period, MDA-MB-231 cell goes through three different stages: cell capture, cell growth, and cell division, which can be measured by changes in impedance. Furthermore, the cellular impedance in ELF-EMF was found to be significantly lower than that of the group without ELF-EMF. In addition, an equivalent circuit was developed to determine the cellular resistance and capacitive reactance, and Maxwell’s mixture theory was used to determine the cell conductivity and permittivity to verify the effects of electromagnetic fields on cell membrane permeability and calcium ion exchange.

(Invited) Spectroelectrochemical Sensors: The Quest for Selectivity

Introduction Exceptional selectivity is needed for sensors to accurately measure analytes in complex samples such as nuclear waste and natural water that contain many potentially interfering substances. Spectroelectrochemistry offers a unique means for providing selectivity by electrochemically modulating the optical signal used for quantitation. The modulated signal can be distinguished from the constant signals of potential interferences. An additional level of selectivity can be provided by adding a very thin film to the transparent electrode to first preconcentrated the analyte while rejecting interferences. Sensors using both visible absorption and fluorescence modes of detection have been developed for detection of organic and inorganic species including ferrocyanide [1] and technetium [2] complexes in nuclear waste and natural water. We have recently extended this research to the spectroelectrochemical investigation of molten salt systems, [3] including lanthanide and actinide measurements related to pyroprocessing [4] and molten salt reactor applications. Thin layer fluorescence-based spectroelectrochemical sensor A planar optically transparent electrode chip was fabricated and characterized for multimode sensing of target species. The chip was comprised of an indium tin oxide (ITO) working electrode, a platinum auxiliary electrode, and a Ag/AgCl reference electrode (Figure 1A,B). Fluorescence was used for detection because limits of detection are typically several magnitudes lower than for absorption spectroscopy and selectivity improved by having adjustable wavelengths for both excitation and emission. A fluorescence spectroelectrochemical measurement using this chip incorporated into an optically transparent thin layer electrochemical (OTTLE) cell was demonstrated using the modulated emission of [Ru(bpy)3]2+. Molten salt absorbance-based spectroelectrochemistry Molten salt systems are of growing interest for a variety of applications, including meeting future energy needs such as molten salt reactors (MSRs). These reactors are of interest for several factors, including the ability to be operated at atmospheric pressures even at extremely high temperatures. The molten salts serve several functions, including heat transfer fluid, reactor coolant, and ability to contain high concentrations of dissolved fuel (plutonium, uranium, thorium). While the benefits of molten salt reactors have been identified, the chemistry of the molten salts is still not understood. Spectroelectrochemistry can provide the tools to characterize, monitor, and control the chemical behavior of fuel species (U, Pu), fission, and corrosion products throughout the molten salt reactor loop. Several of these species are electroactive and have a unique spectroscopic fingerprint that can be optically detected and modulated using electrochemistry. Spectroelectrochemical characterization can provide fundamental information such as concentration, oxidation state, and speciation at any point in the molten salt reactor system. Absorbance-based spectroelectrochemical modulation of uranium was demonstrated in the molten LiCl-KCl eutectic. The unique spectroscopic signatures for U(III) and U(IV) were identified and monitored as it was electrochemically modulated between the U(III)/U(IV) redox states. Based on variable scan-rate cyclic voltammetry, the diffusion coefficients of U(III) and U(IV) were measured. The spectroelectrochemistry of lanthanides and other actinides in chloride melts is being explored for sensor development.

A Universal Nano-capillary Based Method of Catalyst Immobilization for Liquid-Cell Transmission Electron Microscopy.

A universal nano‐capillary based method for sample deposition on the silicon nitride membrane of liquid‐cell transmission electron microscopy (LCTEM) chips is demonstrated. It is applicable to all substances which can be dispersed in a solvent and are suitable for drop casting, including catalysts, biological samples, and polymers. Most importantly, this method overcomes limitations concerning sample immobilization due to the fragility of the ultra‐thin silicon nitride membrane required for electron transmission. Thus, a straightforward way is presented to widen the research area of LCTEM to encompass any sample which can be externally deposited beforehand. Using this method, NixB nanoparticles are deposited on the μm‐scale working electrode of the LCTEM chip and in situ observation of single catalyst particles during ethanol oxidation is for the first time successfully monitored by means of TEM movies.

Impedimetric aptasensing using a symmetric Randles circuit model

Electrochemical impedance spectroscopy (EIS) applied for aptasensing is being extensively studied for a variety of targets. Substitution of a symmetric electrode configuration for a conventional three-electrode setup on EIS aptasensing is becoming a trend due to its simple and favorable characteristics for biochip fabrication. However, a single Randles circuit is often used for impedance element parameter fitting in symmetric electrode aptasensing without rationalized basis of validity to date. In this work, an AC impedance model is derived for proving the validity of simplifying a symmetric Randles circuits in series into a single one and is examined with aptasensing applications. With the model, circuit parameter relationships can be quantified and correlated between symmetric and three-electrode configurations. The relationships are verified by comparing the fitted parameters obtained from standard gold electrodes (SGEs), microfabricated symmetric Au electrodes, and interdigitated array (IDA) Au electrode chips with different surface and detection conditions. The model is then found valid for different redox species composition (either Fe(CN)63− or Fe(CN)63−/4- is used) and for both blank and aptamer modified surfaces. From aptasensing of thrombin and tumor marker mucin 1 (MUC1), it is proved that the measured dissociation constants (KD: 129.4 nM for thrombin and 16.3 nM for MUC1) remain the same between a symmetric and three-electrode configuration, but the maximum change of charge transfer resistance (Bmax) is doubled in the symmetric one. This means that the symmetric configuration not only yields the same KD, but also results in a doubled binding signal for EIS aptasensing. In addition to the model derivation and experimental validation, specific EIS aptasensing of MUC1 using a symmetric electrode configuration is successfully demonstrated in this work.

Dielectrophoretic microfluidic device for separation of red blood cells and platelets: a model-based study

The paper proposes a dielectrophoresis microfluidic chip for particle separation, which uses dielectric properties to perform size-based fractionation of red blood cells and platelets. Based on the control variables, the distribution of the electric field in the chip and the trajectory of the particles in the microfluidic channel are calculated using COMSOL Multiphysics under different electrode shapes, voltages and chip exit structures. Both red blood cells and platelets respond to negative dielectrophoresis at an alternating current signal with a frequency of 100 kHz. The larger red blood cells are subjected to a stronger dielectrophoretic force than the platelets and are biased toward the right outlet, and the platelets flow out from the left outlet under the combined action of fluid force and dielectrophoretic force to achieve the purpose of separation. On this basis, through quantitative comparison and analysis, a more optimized microfluidic chip capable of effectively separating particles is finally selected.

Methanol and Humidity Capacitive Sensors Based on Thin Films of MOF Nanoparticles.

The successful development of modern gas sensing technologies requires high sensitivity and selectivity coupled to cost effectiveness, which implies the necessity to miniaturize devices while reducing the amount of sensing material. The appealing alternative of integrating nanoparticles of a porous metal-organic framework (MOF) onto capacitive sensors based on interdigitated electrode (IDE) chips is presented. We report the deposition of MIL-96(Al) MOF thin films via the Langmuir-Blodgett (LB) method on the IDE chips, which allowed the study of their gas/vapor sensing properties. First, sorption studies of several organic vapors like methanol, toluene, chloroform, etc. were conducted on bulk MOF. The sorption data revealed that MIL-96(Al) presents high affinity toward water and methanol. Later on, ordered LB monolayer films of MIL-96(Al) particles of ∼200 nm were successfully deposited onto IDE chips with homogeneous coverage of the surface in comparison to conventional thin film fabrication techniques such as drop-casting. The sensing tests showed that MOF LB films were selective for water and methanol, and short response/recovery times were achieved. Finally, chemical vapor deposition (CVD) of a porous thin film of Parylene C (thickness ∼250-300 nm) was performed on top of the MOF LB films to fabricate a thin selective layer. The sensing results showed an increase in the water selectivity and sensitivity, while those of methanol showed a huge decrease. These results prove the feasibility of the LB technique for the fabrication of ordered MOF thin films onto IDE chips using very small MOF quantities.

GaN基LED芯片电极结构的优化及制备

GaN基LED芯片电极结构的优化及制备

Gold-Hybridized Zinc Oxide Nanorods as Real-Time Low-Cost NanoBiosensors for Detection of virulent DNA signature of HPV-16 in Cervical Carcinoma

Detection of host integrated viral oncogenes are critical for early and point-of-care molecular diagnostics of virus-induced carcinoma. However, available diagnostic approaches are incapable of combining both cost-efficient medical diagnosis and high analytical performances. To circumvent this, we have developed an improved IDE-based nanobiosensor for biorecognition of HPV-16 infected cervical cancer cells through electrochemical impedance spectroscopy. The system is fabricated by coating gold (Au) doped zinc oxide (ZnO) nanorods interfaced with HPV-16 viral DNA bioreceptors on top of the Interdigitated Electrode (IDE) chips surface. Due to the concurrently improved sensitivity and biocompatibility of the designed nanohybrid film, Au decorated ZnO-Nanorod biosensors demonstrate exceptional detection of HPV-16 E6 oncogene, the cancer biomarker for HPV infected cervical cancers. This sensor displayed high levels of sensitivity by detecting as low as 1fM of viral E6 gene target. The sensor also exhibited a stable functional life span of more than 5 weeks, good reproducibility and high discriminatory properties against HPV-16. Sensor current responses are obtained from cultured cervical cancer cells which are close to clinical cancer samples. Hence, the developed sensor is an adaptable tool with high potential for clinical diagnosis especially useful for economically challenged countries/regions.

An interdigitated microelectrode based aptasensor for real-time and ultratrace detection of four organophosphorus pesticides

With increasing industrialization of food production, residues of organophosphorus pesticides (OPs) are more frequently found in the environment including rivers, lakes and soils. Extended exposure to OPs, even at a level below 1 nM, may lead to liver and central nervous system damages in humans and animals, while existing detection methods are not sensitive enough to detect OPs at trace levels. We presented a simple-to-use aptasensor to rapidly detect broad-spectrum OPs with high sensitivity. DNA aptamer was modified on the surface of a micro interdigitated electrode chip, and AC electrokinetics was employed to accelerate the binding of OP molecules to the aptamer probe. The sensing strategy directly measured the interfacial capacitance whose change rate was adopted as a quantitative indicator of recognition events, with a sample to result detection time of 30 s. This aptasensor had a wide linear range of (fM ~ nM), and the detection limit reached (0.24–1.67) fM for four highly-toxic OPs, with good specificity. It still showed good activity after being stored in non-refrigerated environment for at least 14 days. This aptasensor as well as the detection method offer a promising solution for on-site and real-time sensitive OP detection.

Analysis of aqueous systems using all-inorganic perovskite CsPbBr3 quantum dots with stable electrochemiluminescence performance using a closed bipolar electrode

All-inorganic perovskite CsPbX3 (X = Cl, Br, I) quantum dots (QDs) have emerged as a new class of semiconductor nanocrystals, but the stability of CsPbX3QDs in polar solvents is still a significant challenge.Since most targets in analytical chemistry, especially for biological detection, exist in an aqueous medium, this weakness seriously hampers practical analytical applications of CsPbX3 QDs. In this work, we introduce a closed bipolar electrode (BPE) to extend the application of perovskite QDs to aqueous systems. Based on the principle of conservation of charge in the electrode reactions at opposite ends of the BPE, the concentration of H2O2 in an aqueous medium can be detected by measuring the ECL intensity of CsPbBr3 QDs in an organic solution. Thus, for the first time, H2O2 in an aqueous system has been successfully analyzed using all-inorganic perovskite CsPbBr3 QDs with stable electrochemiluminescence performance combined with a closed bipolar electrode chip.

(Invited) Application of Three Dimensional Chip Stacking Technology for Fully Depleted Silicon-on-Insulator Quantum Beam Imager

A three dimensional (3D) process for a quantum beam imager is proposed. In this process, chip-on-chip stacking scheme with base chips fabricated by fully depleted silicon on insulator (FD-SOI) technology is concerned. Features of the 3D process are the lower and upper chip electrode connection by Au micro-bump and submicron through buried oxide via (TBV) to connect upper bonding pads which is fabricated in wafer processing of the FD-SOI, instead of generally used through silicon via (TSV). The first trial run of the 3D process using pixel level bump bonding in the quantum beam imager was completed. The laser light response of timing memory in the pixel is confirmed. The results indicate potential of the proposed 3D process for the future quantum beam imager.

Prototyping a memristive-based device to analyze neuronal excitability

Many efforts have been spent in the last decade for the development of nanoscale synaptic devices integrated into neuromorphic circuits, trying to emulate the behavior of natural synapses. The study of brain properties with the standard approaches based on biocompatible electrodes coupled to conventional electronics, however, presents strong limitations, which in turn could be overcame by the in-situ growth of neuronal networks coupled to memristive devices. To meet this challenging task, here two different chips were designed and fabricated for culturing neuronal cells and sensing their electrophysiological activity. The first chip was designed to be connected to an external memristor, while the second chip was coated with TiO2 films owning memristive properties. The biocompatibility of chips was preliminary analyzed by culturing the hybrid motor-neuron cell line NSC-34 and by measuring the electrical activity of cells interfacing the chip with a standard patch-clamp setup. Next, neurons were seeded on chips and their activity measured with the same setup. For both cell types total current and voltage responses were evoked and recorded with optimal results with no breakdowns. In addition, an external stimulation was applied to cells through chip electrodes, being effective and causing no damage or pitfalls to the cells. Finally, the whole bio-hybrid system, i.e. the chip interconnected with a commercial memristor, was tested with promising results. Spontaneous electrical activity of neurons grown on the chip was indeed present and this signal was collected and sent to the memristor, changing its state. Taken together, we demonstrated the ability of memristor to work with a synaptic/plastic response together with natural systems, opening the way for the further implementation of basic computing elements able to perform both storage and processing of data, as in natural neurons.

Immunoassays Based on Hot Electron-Induced Electrochemiluminescence at Disposable Cell Chips with Printed Electrodes

Novel hot electron-emitting working electrodes and conventional counter electrodes were created by screen printing. Thus, low-cost disposable electrode chips for bioaffinity assays were produced to replace our older expensive electrode chips manufactured by manufacturing techniques of electronics from silicon or on glass chips. The present chips were created by printing as follows: (i) silver lines provided the electronic contacts, counter electrode and the bottom of the working electrode and counter electrode, (ii) the composite layer was printed on appropriate parts of the silver layer, and (iii) finally a hydrophobic ring was added to produce the electrochemical cell boundaries. The applicability of these electrode chips in bioaffinity assays was demonstrated by an immunoassay of human C-reactive protein (i) using Tb(III) chelate label displaying long-lived hot electron-induced electrochemiluminescence (HECL) and (ii) now for the first time fluorescein isothiocyanate (FITC) was utilized as an a low-cost organic label displaying a short-lived HECL in a real-world bioaffinity assay.

Ultrasensitive Electrochemical Biosensor of Bacterial 16S rRNA Gene Based on polyA DNA Probes.

Traditional microbiology analysis is usually hindered by the long time-cost and lack of portability in many urgent situations. In this work, we developed a novel electrochemical DNA biosensor (E-biosensor) for sensitive analysis of the 16S rRNA gene of five bacteria, using a consecutive adenine (polyA) probe. The polyA probe consists of a polyA tail and a recognition part. The polyA tail can combine onto the gold surface with improved controllability of the surface density, by conveniently changing the length of polyA. The recognition part of the capture probe together with two biotin-labeled reporter probes hybridize with the target DNA and form a stable DNA-tetramer sandwich structure, and then avidin-HRP enzyme was added to produce a redox current signal for the following electrochemical detection. Finally, we realized sensitive quantification of artificial target DNA with a limit of detection (LOD) of 10 fM, and excellent selectivity and reusability were also demonstrated. Importantly, the detection capability was equally good when facing bacterial genomic DNA, due to the base-stacking force of our multireporter-probe system, which can help to break the second structure and stabilize the probe-target complexes. Our biosensor was constructed on a 16-channel electrode chip without any polymerase chain reaction (PCR) process needed, which took a significant step toward a portable bacteria biosensor.

Visual Electrofluorochromic Detection of Cancer Cell Surface Glycoprotein on a Closed Bipolar Electrode Chip.

This work reports an electrofluorochromic strategy on the basis of electric field control of fluorescent signal generation on bipolar electrodes (BPEs) for visualizing cancer cell surface glycoprotein (mucin 1). The device included two separate cells: anodic sensing cell and cathodic reporting cell, which were connected by a screen-printing electrode patterned on poly(ethylene terephthalate) (PET) membrane. In the sensing cell, anti-MUC1 antibody immobilized on a chitosan-multiwalled carbon nanotube (CS-MWCNT)-modified anodic BPE channel was used for capturing mucin-1 (MUC1) or MCF-7 cancer cells. Then ferrocene (Fc)-labeled mucin 1 aptamers were introduced through hybridization. Under an applied voltage, the ferrocene was oxidized and the electroactive molecules of 1,4-benzoquinone (BQ) in the cathodic reporting cell were reduced according to electroneutrality. This produced a strongly basic 1,4-benzoquinone anion radical (BQ•-), which turned on the fluorescence of pH-responsive fluorescent molecules of (2-(2-(4-hydroxystyryl)-6-methyl-4 H-pyran-4-ylidene)malononitrile) (SPM) coexisting in the cathode reporting cell for both spectrophotometric detection and imaging. This strategy allowed sensitive detection of MUC1 at a concentration down to 10 fM and was capable of detecting a minimum of three MCF-7 cells. Furthermore, the amount of MUC1 on MCF-7 cells was calculated to be 6.02 × 104 molecules/cell. Our strategy also had the advantages of high temporal and spatial resolution, short response time, and high luminous contrast and is of great significance for human health and the promotion of life science development.

Rapid and Low-Cost Field Detection of Marine Toxins

Brevetoxins (PbTx) are a group of marine algal toxic compounds that are produced by the bloom-forming dinoflagellate Karenia brevis. During harmful algal blooms (HAB), brevetoxins can reach concentrations high enough to cause human neurological and gastrointestinal illnesses through inhalation of the airborne toxins or consumption of contaminated shellfish. The timely recognition of this toxin in marine environment is of great importance for public safety, human health, human recreation, marine ecology, and the marine economy. We present the development of a low-cost and easy-to-use electrochemical test for rapid and quantitative detection of brevetoxin species in seawater. Specifically, we utilize an assay to enable measurement of PbTx-2 and PbTx-3 with high specificity while lowering the field detection limits to sub-parts-per-billion (ppb) levels via unique use of disposable electrode chips. Key sensor specifications include PbTx-2 detection limit of 0.25 ppb, a linear range of 0.25 - 50 ppb, and sample-to-result turnaround time of < 5 minutes. The assay also works interference-free; the measured electrochemical signal maintains 90% of its magnitude in seawater in the presence of other aquatic toxins. This versatile field sensor will allow near real-time monitoring of brevetoxin levels in seawater throughout the progression of a red tide bloom. Additionally, our platform technology has the potential to monitor shellfish toxins and could find applications in seafood safety where rapid, accurate, and selective detection of toxins is needed.