Interdigitated Electrode Sensor Research Articles

Zeolite-iron oxide integrated interdigitated electrode sensor for diagnosing cervical cancer

Cervical cancer is caused by changes in the cervix that lead to precancerous cells and eventually progress to cancer. Human papillomavirus (HPV) infections are the primary cause of cervical cancer. Early detection of HPV is crucial in preventing cervical cancer, and regular screening for HPV infection can identify cell changes before they develop into cancer. While Pap smear tests are reliable for cervical cancer screening, they are critical, expensive, and labor-intensive. Therefore, researchers are focusing on identifying blood-based biomarkers using biosensors for cervical cancer screening. HPV strains 16, 45, and 18 are common culprits in cervical cancer. This study aimed to develop an HPV-16 DNA biosensor on a zeolite-iron oxide (zeolite-IO) modified interdigitated electrode (IDE) sensor. The DNA probe was immobilized on the IDE through amine-modified zeolite-IO, enhancing the hybridization of the target and DNA probe. The detection limit of the DNA-DNA duplex was found to be 7.5 pM with an R2 value of 0.9868. Additionally, control experiments with single and triple mismatched sequences showed no increase in current responses, and the identification of target DNA in a serum-spiked sample indicated specific and selective target identification.

Design methodology for optimal sensor placement for cure monitoring and load detection of sensor-integrated, gentelligent composite parts

AbstractSelecting right positions for composite-integrated sensors for monitoring cure during manufacturing and loads during product use presents challenges for engineering design. Since an optimal sensor placement (OSP) methodology for both phases is not emphasised enough in literature, a new methodology is proposed. This methodology is based on a Genetic Algorithm and strain gauges, temperature sensors and interdigitated electrode sensors for cure monitoring and physics-informed neural network-based load detection. Additionally, it includes sensor node positions optimization in a sensor network.

High-sensitivity immunoassay on interdigitated electrode to detect osteoporosis biological marker.

Osteoporosis is with porous bones, which refers to a decrease in the bone mineral density and weakens the bones to become brittle. Osteoporosis often progresses without any pain or symptoms until the bone fractures. Monitoring the condition of bone regularly helps to identify the bone that weakens at its earlier stages. In general, radiological techniques have been used to measure bone mineral density, are expensive, and the procedures are complicated. Therefore, researchers are focusing on the alternative method of biomarker quantification to identify bone mineral density. This research work was focused on quantifying the osteoporosis biomarker of C-terminal telopeptide of type I collagen (CTX-I) on an interdigitated electrode (IDE) sensor. Gold nanomaterial-modified anti-CTX-I antibody was attached to silica nanomaterial-decorated IDE and then identified by CTX-I interaction. Higher immobilization of antibodies was recorded on diamond-modified IDE through gold nanoparticles, and detected CTX-I as low as 0.5pg/mL [y = 1.5507x-0.9043 R2 = 0.9715], determined on a linear curve at the range 0.5-3.5ng/mL. Further, specific identification of CTX-I was confirmed by control performances with osteopontin, IL-6, and anti-IgG antibody.

Nanocasting technique for imprinting a natural leaf pattern on biomimetic polyaniline to yield an artificial hierarchical surface structure for gas sensing

Hydrogen sulfide (H2S) posed substantial safety risks in industrial settings due to its odorless and toxic nature and necessitated vigilant detection. With the burgeoning importance of H2S gas sensing applications, this study focused on the synthesis and utilization of a novel biomimetic material aimed at advancing gas sensing capabilities. Biomimetic polyaniline (Bio-PANI) with an artificial hierarchical surface structure was fabricated through the innovative nanocasting technique. This technique involved the replication of the surface pattern of a natural Xanthosoma sagittifolium leaf (XSL) onto a PANI coating, achieved using a negative template. In comparison to PANI, Bio-PANI showcased higher specific surface area (160 m2/g versus 41 m2/g of PANI) and exhibited significantly amplified reversible redox and doping–dedoping capacities. The application of Bio-PANI and PANI coatings on interdigitated electrodes (IDEs) allowed for gas-sensing assessments. These evaluations encompassed as-prepared IDE sensor’s responsivity, selectivity, repeatability, and stability. Notably, the Bio-PANI-coated IDE sensor showed larger response (185% versus 27% of PANI toward a 10 ppm concentration of H2S), a consequence of their substantially larger specific surface area and greater electrochemical performances when contrasted with PANI-coated IDE sensor. In addition, Bio-PANI-coated IDE sensor exhibited better selectivity, repeatability, long-term stability, and moisture resistance.

Spinal cord injury immunosensor: Sensitive detection of S100β on interdigitated electrode sensor

A spinal cord injury is damage to the nerves and cells that receive and provide a signal from the brain to the rest of the body. Spinal injury causes changes in movement, sensation, and strength, affect the body functions near the injury site, and may lead to paralysis. S100β was found as a suitable biomarker for identifying spinal cord injury and its causing problem. Herein, S100β immunoassay was developed on interdigitated electrode sensor to diagnose spinal cord injury. For effective anti-S100β antibody immobilization, the antibody was premixed with 3-Aminopropyl)triethoxsilane and then attached to the hydroxylated interdigitated electrode surface. This method of antibody immobilization enhanced the antibody attachment two-times than the method without premix. Antibody-attached surfaces increased current responses as S100 concentrations increased, and the limit of detection was seen to be 1 pg/mL on the linearity until 3000 pg/mL at an R2 value of 0.9907 [y = 7x - 6.4667]. Further, biofouling experiments with glial fibrillary acidic protein and γ-aminobutyric acid failed to enhance the current response, indicating the specific detection of S100β. This immunoassay identifies S100β at its lower level and helps to diagnose spinal cord injury and its related problem.

Development of Rapid Dispense-Printed Flexible Interdigitated Electrode Modified with rGO-TiO2 Nanohybrid for Glucose Detection

A rapid and facile method in developing a printed electrochemical glucose sensor constructed using flexible interdigitated electrode (IDE) employed with reduced graphene oxide (rGO)-Titanium dioxide (TiO2) is demonstrated. A 2 × 3 silver (Ag)-based IDE array based on a simulated IDE model, was fabricated via a single-step dispense-printing within less than 5 min, while a rGO-TiO2 nanohybrid and glucose oxidase (GOx) enzyme was coated on the IDE surface simply via drop-casting method. Exceptional reproducibility and repeatability of the printed IDE functionalized with rGO-TiO2/GOx in terms of electrical and mechanical performance were observed. The stability of the sensor was investigated over a week period, in which 6%–7% performance degradation was recorded based on resistance measurement in flat state, whereas no further significant loss was noted over the same period in bending state. The IDE sensor was tested using chronoamperometry with varied glucose concentrations up to 30 mM, resulted in a stabilized current after 5 s. The sensitivity plot attained depicted a best linear fit of 0.988 obtained at response time of 60 s, whilst covering lowest detection at 0.05 mM and selective detection from ascorbic acid and uric acid. The application of this sensor could contribute as an alternative method to develop a reliable and economical glucose sensing wearable for independent monitoring.

Optimal interdigitated electrode sensor design for biosensors using multi-objective particle-swarm optimization

<p>Interdigitated electrodes (IDEs) are commonly employed in biological cellular characterization techniques such as electrical cell-substrate impedance sensing (ECIS). Because of its simple production technique and low cost, interdigitated electrode sensor design is critical for practical impedance spectroscopy in the medical and pharmaceutical domains. The equivalent circuit of an IDE was modeled in this paper, it consisted of three primary components: double layer capacitance, C<sub>dl</sub>, solution capacitance, C<sub>Sol</sub>, and solution resistance, R<sub>Sol</sub>. One of the challenging optimization challenges is the geometric optimization of the interdigital electrode structure of a sensor. We employ metaheuristic techniques to identify the best answer to problems of this kind. multi-objective optimization of the IDE using multi-objective particle swarm optimization (MOPSO) was achieved to maximize the sensitivity of the electrode and minimize the Cut-off frequency. The optimal geometrical parameters determined during optimization are used to build the electrical equivalent circuit. The amplitude and phase of the impedance versus frequency analysis were calculated using EC-LAB® software, and the corresponding conductivity was determined.</p>

Development of interdigitated electrode based enzyme sensor for triglyceride monitoring using engineered oxygen insensitive glycerol 3-phosphate oxidase

Triglycerides (TG) are an important biomarker of various diseases including hyper-lipidemia. Current emergent requirements for TG sensing include the development of electrochemical sensors for easy, cost-effective, disposable and single use triglyceride sensors. We propose a TG sensor using an engineered glycerol 3-phosphate oxidase (GlpO) and electrochemical detection. In this study, we aimed to develop an electrochemical TG sensor based on engineering the oxidative half reaction of GlpO to be oxygen insensitive, with the employment of an interdigitated electrode (IDE). To construct an oxygen insensitive mutant GlpO, we constructed a double mutant, Met104Phe/Asp169Glu, which revealed an engineered GlpO exhibiting repressed oxidase activity, while its dye-mediated dehydrogenase activity enhanced. The electrochemical enzyme sensor was constructed for the measurement of TG based on engineered GlpO using disposable screen-printed carbon electrode (SPCE) or disposable IDE using Ru complex as the electron mediator. By using the disposable IDE sensor, a highly sensitive electrochemical sensor for Glp was achieved, with the sensitivity of 0.4 µA/mM. The improved sensitivity was 2.4 times higher than that of SPCE (0.17 µA/mM), with LOD of 0.022 mM. Furthermore, the dry sensor strip, where the double mutant GlpO and Ru complex were dropcasted and dried on the IDE, was prepared and the Glp concentration was successfully measured in the delipidized serum solution. Therefore, by the employment of the established pretreatment method for TG to release Glp, a highly sensitive, accurate, easy and rapid electrochemical measurement method for TG will be developed using constructed M104F/D169E mutant GlpO with the combination of IDE.

Three Different Rapidly Prototyped Polymeric Substrates With Interdigitated Electrodes for Escherichia coli Sensing: A Comparative Study.

This work delves upon the development of different types of miniaturized and 3D printed devices having interdigitated electrodes (IDEs) for the detection of Escherichia coli (E. coli) bacteria. The IDEs were fabricated using different approaches including laser-induced graphene (LIG) on polyamide, direct laser writing on glass, and polymeric 3D printing technique, and their suitability for bacteria detection has been compared. The electrochemical impedance spectroscopy (EIS) technique was employed to detect the E. coli bacteria in the prepared miniaturized devices, and the sensory response was compared. EIS was performed in the frequency range between 1 Hz to 1 MHz to record the bacterial growth and activities as a function of change in electrical impedance, and detection performance of the different miniaturized devices with IDEs were compared. It was observed that the LIG-based IDE sensor provided better sensitivity compared to that of the other two approaches. The obtained results indicate that the magnitude of impedance changes by around 2.5 [Formula: see text] per doubling of E.coli cells. With fast and flexible fabrication process capabilities, such microdevices may be used as suitable IDE sensors for microscale pathogenic detection for biomedical and clinical analysis.

Capacitive Interdigitated Electrodes Sensor for the Field Device to Measure Moisture Content in the Nitrile Gloves Manufacturing Industry

This paper investigates the impedance spectroscopy technique in determining moisture content in Nitrile gloves. Interdigitated electrode was designed and fabricated, then evaluated on LCR Impedance meter subjected to frequency range of 100Hz, 120Hz, 1kHz, 10kHz, 20kHz and 100kHz. Samples of Nitrile gloves were compounded and prepared for different moisture content level and regression analysis was performed to evaluate the relationships between capacitance and moisture content of the glove samples. Experimental results indicated that the capacitance value is a strong function of moisture content in gloves and also that the capacitance of moisture content in Nitrile gloves decreased with increasing drying time over the measured frequency range whilst statistical analysis results have confirmed that the 1kHz, 10kHz and 20kHz signal frequencies have highest reliable prediction of the nitrile gloves’ moisture content with high R2 value of 0.96, 0.97 and 0.97, respectively. The ability to determine average moisture content of Nitrile gloves via a non-destructive and online method, utilizing a low-cost instrument, will be of considerable use in the glove industry. This method could also be extended to other types of gloves and rubber products.

Graphite-Based Multianalyte VOC Gas Detection on Multichannel PCB IDE Sensor

In this article, we present the development of a volatile organic compound (VOC) gas sensor based on graphite on a printed circuit board (PCB) multiplexed interdigitated electrode (IDE) sensor. We report the effects of graphite as a sensing material deposited by the spray method and its interaction response to specific gases. In addition, we demonstrate how we designed and manufactured IDE sensors with an integrated heating circuit and thermistor element, as well as the 55- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{L}$ </tex-math></inline-formula> microchamber, which contributed to the fast detection of gases. All experiments were performed with four IDE sensors to verify the reproducibility and sensitivity of the proposed methodology. Our results highlight that acetone presented the highest detection sensitivity, with an electric current increase of ± <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$100~\mu \text{A}$ </tex-math></inline-formula> at a 200-ppm cycle with a response of 0.92 s and full recovery at 2.62 s. Furthermore, the developed sensors were able to detect and distinguish between acetone, methanol, isopropanol, ethanol, and chloroform gases. The sensors exhibited outstanding stability and repeatability when evaluated after six months. The sensors’ operation at 2 V makes it suitable for low-power devices with a high potential to be applied in future commercial room-temperature VOC gas sensor devices.

Geometrical Optimization of Printed Interdigitated Electrode Sensors to Improve Soil Moisture Sensitivity

Printing electronics allows us to fabricate low-cost, simple sensor networks. Distributed soil moisture sensors in agriculture industry will result in better water management practices; however, price and reliability do not allow for ubiquitous availability. Here, we demonstrate the fabrication of low-cost, flexible, interdigitated electrode (IDE) soil moisture sensors with the electrode widths of 537, 877, 1055, 1204, and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1916~\mu \text{m}$ </tex-math></inline-formula> on polyimide (PI) substrates using a silver nanoparticle (Ag NP) ink. The sensors were tested in sandy textured soil with a volumetric water content ranging from 0.05 to 0.25 m3/m3. Analytically, the sensitivities of all the sensors are expected to be equal, as the proposed mechanisms dictate that the capacitance should depend linearly on the dielectric constant of the moist soil. However, we found the sensitivity for the widest IDE, which measured <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1916~\mu \text{m}$ </tex-math></inline-formula> to be 442 pF/H2O volumetric percentage, whereas the sensitivity for the sensor with 537- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> -wide electrodes to be only 221 pF/H2O volumetric percentage. We hypothesized that the increase in sensitivity can be directly related to the increase in the capacitive fringing field height, which results in increased sensing volume for the widest IDE. The increased sensing volume leads to increased water molecule polarization, increasing the overall capacitance change with respect to changing water content. To validate the hypothesis, we conducted electric fringing field experiments to observe the trend between the maximum fringing field height and the electrode width of an IDE. Results confirmed that increased sensing volume was caused by the increased fringing field height of the electrode in an IDE.

Cardiovascular biomarker troponin I biosensor: Aptamer-gold-antibody hybrid on a metal oxide surface.

Myocardial infarction (MI) is highly related to cardiac arrest leading to death and organ damage. Radiological techniques and electrocardiography have been used as preliminary tests to diagnose MI; however, these techniques are not sensitive enough for early-stage detection. A blood biomarker-based diagnosis is an immediate solution, and due to the high correlation of troponin with MI, it has been considered to be a gold-standard biomarker. In the present research, the cardiac biomarker troponin I (cTnI) was detected on an interdigitated electrode sensor with various surface interfaces. To detect cTnI, a capture aptamer-conjugated gold nanoparticle probe and detection antibody probe were utilized and compared through an alternating sandwich pattern. The surface metal oxide morphology of the developed sensor was proven by microscopic assessments. The limit of detection with the aptamer-gold-cTnI-antibody sandwich pattern was 100 aM, while it was 1 fM with antibody-gold-cTnI-aptamer, representing 10-fold differences. Further, the high performance of the sensor was confirmed by selective cTnI determination in serum, exhibiting superior nonfouling. These methods of determination provide options for generating novel assays for diagnosing MI.

Sensitive Aptasensing of Hepatitis B Viral Antigen Gold Dielectrode by Current-Volt Measurements

Hepatitis B virus (HBV) is a serious human health issue, primarily leading to cirrhosis, chronic hepatitis, and primary liver cancer. Patients are at higher risk of a poor prognosis if the viral load exceeds &gt;105 copies/mL; hence, it is crucial to identify the early stages of HBV infection. This research aimed to identify hepatitis B surface antigen (HBsAg) on an interdigitated gold electrode sensor assisted by HBsAg-specific aptamer and antibody interactions. The aptamer-HBsAg-antibody sandwich assay was carried out on an interdigitated electrode using aptamer as the capture molecule and anti-HBsAg antibody as the detection molecule. Higher capture probe immobilization was achieved through the gold nanourchin conjugated capture aptamer. On the aptamer-attached electrode, HBsAg interacted with and was sandwiched by the detection antibody. The sandwich assay lowered the limit of HBsAg detection to 0.1 ng/mL, as indicated by the calculated R2 value of 0.9915 on a linear regression graph presenting data for concentrations of HBsAg from 0.1 to 60 ng/mL. Furthermore, specific HBsAg detection was confirmed by complementarity of the capture aptamer sequence and nonspecific proteins (hepatitis C-the core antigen (HCVcoreAg) and albumin). A selective experiment revealed a gradual increase in current responses in a HBsAg-spiked serum sample, demonstrating the interference-free detection of HBsAg for the real-life sample.

Evaluating glioma-associated microRNA by complementation on a biological nanosensor.

Glioma is a tumor in the brain and spinal cord originating in the glial cells that surround the nerve cells. Among several microRNAs reported, miRNA-363 is associated with human glioma. Based on miRNA-363 levels, the development and progression of glioma can be monitored. The current study used an interdigitated electrode sensor to monitor microRNA-363 levels, which indeed reflects the severity of glioma. The interdigitated electrode was generated using a photolithography technique followed by surface chemical modification carried out to insert miRNA-363 complementary oligo as the probe complexed with gold nanoparticles. The proposed sensor works based on the dipole moment between two electrodes, and when molecular immobilization or interaction occurs, the response by the signal output changes. The changes in the target microRNA-363 sequence were standardized to identify glioma. The limit of detection of miRNA-363 was 10 fM with an R2 value of 0.996 on the linear coefficient regression ranges between 1 fM and 100 pM. Furthermore, unrelated sequences failed to increase the response of the current with the complementary probe, indicating specific miRNA-363 detection on the interdigitated electrode. This study demonstrates the platform to be used for determining the presence of microRNA-363 in glioma and as the basis for other biomarker analyses.

Carbon Material Hybrid Construction on an Aptasensor for Monitoring Surgical Tumors.

Carcinoembryonic antigen (CEA) is a glycoprotein, one of the common tumor biomarkers, found at low levels in body fluids. Generally, overexpression of CEA is found in various cancers, including ovarian, breast, lung, colorectal, gastric, and pancreatic cancers. Since CEA is an important tumor biomarker, the quantification of CEA is helpful for diagnosing cancer, monitoring tumor progression, and the follow-up treatment. This research develops a highly sensitive sandwich aptasensor for CEA identification on an interdigitated electrode sensor. Carbon-based material was used to attach a higher anti-CEA capture aptamer onto the sensor surface through a chemical linker, and then, CEA was quantified by the aptamer. Furthermore, CEA-spiked serum was tested by using the immobilized aptamer, which was found to not affect the target validation. The limit of detection for CEA in PBS and serum is calculated from a linear regression graph to be 0.5 ng/mL with R2 values of 0.9593 and 0.9657, respectively, over a linear range from 0.5 to 500 ng/mL. This CEA quantification by the aptasensor can help diagnose various surgical tumors and monitor their progression.

A novel electrochemical interdigitated electrodes sensor for limonin quantification and reduction in citrus limetta juice

Limonin, a highly oxygenated triterpene biomolecule of citrus fruits is responsible for delayed bitterness of its juice lowering consumer’s acceptability. Hence, limonin detection is essential for appropriate debittering intrusions. A novel interdigitated capacitive sensor using magnesium silicate-poly vinyl alcohol (MgSiO3.xH2O-PVA) composite has been introduced for quantification of limonin and debittering through selective adsorption of limonin from the citrus limetta juice. The sensor showed high sensitivity of 2.392 µF/ppm and fast response time of ∼6s. The sensor enables both quantification as well as measure debittering of citrus juice showing a reduction in limonin content from 5.77 ppm to 4.29 ppm with an exposure time of 60s to the sensing material making it distinctive in comparison to other methods. The sensor’s results were validated with HPLC analysis. The device is simple, low-cost and reusable which promises easy, on-site and rapid quantification and reduction of limonin content in citrus juices without having toxicity.

Zinc oxide and gold textured Janus nanowire integration in an impedimetric sensor for leptospirosis DNA-biomarker recognition.

A "Janus particle" refers to the production of two materials in a single system and shows a difference in physical characteristics, and two surfaces participate in the formation with different chemistries. This research generated the Janus using a hybrid of zinc oxide (ZnO) and gold (Au) on the sensor surface toward making high-performance DNA sensors. The Janus ZnO/Au-textured film was synthesized via the one-step sol-gel method, which involves a suitable ratio of a mixture of ZnO sol seed solution. The synthesized Janus ZnO/Au-textured film undergoes a low-temperature aqueous hydrothermal route to synthesize quasi-one-dimensional nanowires. The average grain size in the Janus ZnO/Au nanotextured wire was 41.60 nm. The fabricated nanotextured wire was further optimized by tuning the thickness and characterized by XRD and high-resolution microscopy. Electrical characterization was conducted on the Janus ZnO/Au nanotextured wire coupled with an interdigitated electrode sensor to detect the specific leptospirosis DNA strand. The generated device is capable of detecting lower DNA concentration at 1 × 10-13 M with a sensitivity of 8.54 MΩ M-1 cm-2 . The high performance is attained on linear concentrations of 10-6 -10-13 M with the determination coefficient, "I = 135437.63C-3609.07" R2 = 0.9551. A potential strategy is proposed as a base for developing different high-performance sensors.

Biosensing epidemic and pandemic respiratory viruses: Internet of Things with Gaussian noise channel algorithmic model.

The current world condition is dire due to epidemics and pandemics as a result of novel viruses, such as influenza and the coronavirus, causing acute respiratory syndrome. To overcome these critical situations, the current research seeks to generate a common surveillance system with the assistance of a controlled Internet of Things operated under a Gaussian noise channel. To create the model system, a study with an analysis of H1N1 influenza virus determination on an interdigitated electrode (IDE) sensor was validated by current-volt measurements. The preliminary data were generated using hemagglutinin as the target against gold-conjugated aptamer/antibody as the probe, with the transmission pattern showing consistency with the Gaussian noise channel algorithm. A good fit with the algorithmic values was found, displaying a similar pattern to that output from the IDE, indicating reliability. This study can be a model for the surveillance of varied pathogens, including the emergence and reemergence of novel strains.

Optimal Interdigitated Electrode Sensor Design for biosensors using Differential Evolution Algorithm

Optimization of interdigitated electrode sensor design is essential for practical impedance spectroscopy in the medical and pharmaceutical fields because of their easy fabrication procedure and inexpensive. The geometry presents a prospective for ameliorating sensitivity over other microelectrode designs. The geometric optimization of a sensor’s structure with interdigital electrodes is one of the difficult optimization problems. To solve this type of problem, we use metaheuristic methods to find the optimal solution. The method chosen in this paper is the differential evolution algorithm DE, which is widely used to solve the overall optimization problem. We will optimize the geometrical parameters of the interdigitated electrodes by minimizing the FLow, the proper band [FLow&lt;--&gt;FHigh] using MATLAB script, the validity of the obtained results is investigated using ADS tools