Biosensors and Bioelectronics: X最新文献

Viruses are infectious agents that cause various diseases worldwide. The recent COVID-19 pandemic has shown the need for rapid and reliable tests to confirm viral infections, aiming at the rapid isolation, treatment, and identification of high-incidence regions. Rapid antigen tests based on lateral flow immunochromatography have proven to be very useful. However, they are not accurate in patients with low viral loadings. The gold standard test is RT-PCR, which identifies parts of the viral genome by detecting specific DNA or RNA sequences. RT-PCR or similar tests such as RT-LAMP involve several steps for sample preparation and amplification of target sequences, require trained personnel to be performed, and can be time-consuming and expensive, limiting their point-of-care application. Biosensors are promising analytical devices for detecting nucleic acids, mainly RNA from viruses, offering advantages such as rapid results, high sensitivity, and low cost compared with the RT-PCR test since the amplification of target sequences is not necessary. Recently, several biosensors have been developed to detect RNA viruses without sequence amplification. Here, we present a review on the design and technology of amplification-free biosensors for the detection of viral RNA as an alternative for diagnosing infectious diseases. The challenges and advances for the point-of-care electrochemical, electrical, and optical biosensors will be addressed.

In this study, we examined the relationship between the sensitivity of interdigitated electrode (IDE) impedimetric biosensors and the gap between the IDEs. Our aim is to find an optimal design to maximize sensitivity. A three-dimensional COMSOL model was constructed for determining the effects of electrode gap, width, and height on impedance sensitivity, revealing a singular linear correlation with the inner gap. Considering both the simulation results and fabrication processes, we have developed three IDE prototype chips with electrode gaps of 3 μm, 4 μm, and 5 μm, respectively. For empirical validation, human anti-SARS-CoV-2 monoclonal antibody (mAb) was utilized, with immobilization of the SARS-CoV-2 spike protein on the chip's surface for mAb capture. This interaction, further amplified by Protein G conjugation, induced shifts in the impedance spectrum. The sensitivity of each prototype chip was evaluated across mAb concentrations ranging from 50 ng/mL to 500 ng/mL. The 3 μm configuration emerged as the most sensitive, demonstrating the ability to detect mAb concentrations as low as 50 ng/mL, a threshold unattainable by the other designs. This outcome underscores the critical influence of reduced inter-electrode gap on enhancing biosensor detection limits. The findings from this investigation offer a foundational approach for advancing biosensor sensitivity via electrode geometric optimization, with broad potential applications extending beyond COVID-19 diagnostics to a wide spectrum of clinical and research contexts.

Early prostate cancer detection can be improved by detecting more specific markers like PCA3 RNA. This study reports a novel and simple method for detecting PCA3 RNA using a sensor based on reduced graphene oxide (RGO), gold nanoparticles (AuNP), and a single-stranded DNA (ssDNA). The device was characterized at each fabrication step using atomic force microscopy (AFM) and field emission scanning electron microscopy (FESEM). The RGO/AuNP/ssDNA sensor exhibited a significant change in resistance (6.51–15.01%) when exposed to varying concentrations of PCA3 (0.1–100 ng/mL). The developed device showed selective response towards PCA3 (14.5% for 50 ng/mL) when compared with negative controls like phosphate buffer saline solution (0.28%), PCA3-negative control sample (1.03%), RNA extracted from lung cancer (0.88%), and breast cancer (1.17%) cell lines. The RGO/AuNP/ssDNA sensor could also be employed to quantify the PCA3 RNA present in the RNA mixture extracted from a prostate cancer cell line and the observed findings were in excellent agreement with semi-quantitative real-time polymerase chain reaction (RT-PCR) results.

High concentrations of H₂O₂, indicative of increased oxidative stress in the lung, are observed in the exhaled breath of individuals affected by different respiratory diseases. Therefore, measuring H₂O₂ in exhaled breath represents a promising and non-invasive approach for monitoring the onset and progression of these diseases. Herein, we have developed an innovative, inexpensive, and easy-to-use device for the measurement of H₂O₂ in exhaled breath. The device is based on a silver layer covered with an electrodeposited thin film of chitosan, that ensures the wettability of the sensor in a humid atmosphere. The s-ensor was calibrated in the aerosol phase using both phosphate buffer solution and cell culture medium. In the buffer, a sensitivity of 0.110 ± 0.0042 μA μM⁻¹ cm⁻² (RSD: 4%) and a limit of detection of 30 μM were calculated, while in the cell culture medium, a sensitivity of 0.098 ± 0.0022 μA μM⁻¹ cm⁻² (RSD 2%) and a limit of detection of 40 μM were obtained. High selectivity to different interfering species was also verified. The sensor was further tested versus an aerosol phase obtained by nebulizing the culture medium derived from human bronchial epithelial cells that had been exposed to pro-oxidant and antioxidant treatments. The results were comparable with those obtained using the conventional cytofluorimetric method. Finally, sensor was tested in real exhaled breath samples and even after undergoing physical deformations. Data herein presented support that in future applications this device can be integrated into face masks allowing for easy breath monitoring.

The detection of endogenous hormones is of great significance for disease diagnosis, treatment guidance, and the development of personalized healthcare. By using biosensors, real-time monitoring and quantitative analysis of endogenous hormone levels can be achieved, providing scientific basis for clinical decision-making. The continuous innovation in this field will bring new breakthroughs in medical diagnosis and treatment, which are expected to accelerate the early detection of diseases and the implementation of personalized treatment plans. In this review, we mainly review the research progress of endogenous hormone biosensors based on different biological recognition elements, namely enzyme-based biosensors, immunobiosensors, aptamer-based biosensors, and molecularly imprinted polymer (MIP) based biosensors. Meanwhile, this paper also analyzes the detection efficiency and clinical application of these biosensors. Finally, we summarize the current challenges and future development directions of the different types of biosensors involved in the discussion.

The overexpression of folate receptors on cell surfaces is associated with abnormalities linked to epithelial cancers. This study reports on a capacitive biosensor that employs folic acid as a recognition molecule for the biosensing of folate receptors. The biosensor is composed of a thin film of Ti–W oxides conjugated with folic acid that serves as a working electrode in a three-electrode electrochemical cell configuration. The thin film of Ti–W oxides, featuring a mixture of TiO₂ anatase and rutile phases, was fabricated using the pulsed laser deposition method and subsequently functionalized with folic acid. Characterization of the thin film before and after functionalization was conducted using AFM, XPS, and contact angle measurements. The functionalization study confirmed a stable bond between folic acid and the surface of the thin film. The interaction between the functionalized transducer and the folate receptor was investigated by determining the electrochemical capacitance using an electrochemical capacitance spectroscopy setup. Folate receptor recognition assays demonstrated that the biosensor response signal, or chemical hardness (in terms of electrochemical capacitance), is selective and directly proportional to the folate receptor concentration, with a limit of detection of 200 pM (0.2 nM). These findings are promising for the application of this detector in the recognition of folate receptors, particularly for point-of-care analysis.

The ongoing COVID-19 pandemic continues to have a significant impact on our daily lives, necessitating the rapid development of early diagnostic tools to mitigate the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreaks. In this context, biosensor technology has emerged as a highly promising strategy to address the challenges of low sensitivity, specificity, and high cost associated with clinical diagnosis. In this study, we present a novel and cost-effective approach for the rapid detection of SARS-CoV-2 using miniaturized flexible carbon fiber (FCF) electrodes that are modified with immunoglobulin G (IgG). Our strategy take advantage of on the antigen-antibody interaction (IgG-SARS-CoV-2) and leverages the surface chemistry characteristics of FCF to achieve signal amplification. Under standard conditions, we achieved a remarkable detection limit of 0.16 pg mmL⁻¹ for the SARS-CoV-2 RBD protein. Additionally, when analyzing human saliva samples, our biosensing approach demonstrated good agreement with RT-PCR results, specifically for patients who tested positive for SARS-CoV-2. The sensitivity, selectivity, and accuracy of our approach were approximately 93.3%.

A technology that can effectively distinguish between various odorants with high sensitivity and selectivity has numerous applications ranging from water quality testing to disease diagnosis. Here, we report a cell-based odorant-sensing display that utilizes Sf21 cells expressing odorant receptors, co-receptors, and a calcium-sensitive fluorescent protein as the sensing elements for detecting multiple odorants. Integrated micropatterns of the sensor cells in a few hundred micrometer-size patterns were fabricated on photoactivatable cell-anchoring surfaces consisting of photo-responsive polymeric materials. In the microfluidic system equipped with the sensing display, the injection of two model odorants, such as Bombykal and 1-octen-3-ol, at micro-molar concentrations resulted in selective and rapid fluorescence emission from the corresponding sensor cell patterns. Furthermore, when both odorants were injected together, the fluorescence from each corresponding sensor cell could be observed simultaneously. This study provides the proof of principle that the current cell patterning system enables the discrimination of odors, including multiple odorants, through a finely patterned sensing display on the device.

Diabetes mellitus, known as diabetes, is a chronic disease that affects the control of blood glucose concentration levels, it is a disease that mostly affects adults (type 2 diabetes), but it can also occur in children (type 1 or childhood diabetes), as well as in pregnant women (gestational diabetes). Diabetes is one of the diseases with the highest prevalence and high mortality worldwide. Diabetes has no cure, but continuous monitoring to maintain blood glucose levels in normal ranges reduces the possibility of suffering from gastrointestinal problems, vision loss, limb amputations (such as diabetic foot) and damage to vital organs such as the heart and kidneys, among other associated complications. This article compares the results in glucose estimation by using a linear, quadratic and cubic regression considering the electrical characteristics generated in the cardiac conduction (HR, HRV, T-wave peak, and QT interval) recorded on a single-lead electrocardiogram (VII), used as a non-invasive blood glucose estimation model. The best estimate was obtained using a cubic regression. The validation was performed using the Clarke grid having 77.78 % of data in the A zone and 22.22 % in the B zone and a Pearson correlation value of 0.94103 in the cubic regression.

The advent of 3D printing technology has spurred innovation, particularly in healthcare and biosensing. One notable application is the creation of wearable biosensors for detecting substances like ketamine, a potent anesthetic and pain reliever with medical and recreational uses. Monitoring ketamine levels is crucial due to potential misuse and health risks. Utilizing 3D printing, manufacturers can produce intricate and customizable wearable biosensors designed for ketamine detection. This flexibility permits the incorporation of various sensor types, enhancing accuracy. Traditional detection methods are often cumbersome, making 3D printing a transformative tool for real-time monitoring. The application of 3D printing in wearable biosensors has the potential to revolutionize personalized healthcare, ensuring the safe and effective usage of ketamine. In this paper 3D printed paper-based wearable aptamer cassette (3DP-PWC) has been developed by immobilizing Ketamine Aptamer on ZnO-NPs electrodes. Electrochemical techniques such as cyclic voltammetry (CV), linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) were employed for validating results. The sensor’s versatility was demonstrated across beverages encompassing both alcoholic and non-alcoholic options. Two prototypes—a bracelet and a pendant—were developed and compared, showing promising results. Here, we reported a 3D-printing paper based wearable aptasensor for the ketamine detection. This pioneering developed sensor showed a low limit detection (LOD) of 0.01 μg/mL (lower than the physiological detection threshold 0.084 μg/mL) with linear-range was between 0.01 and 5 μmL and an optimal response time of 25 s.