Biosensor For Detection Research Articles

Low-cost signal enhanced colorimetric and SERS dual-mode paper sensor for rapid and ultrasensitive screening of mercury ions in tea

Mercury ions (Hg2+) are highly toxic heavy metals that are commonly found in natural environments. Owning to their non-biodegradability and accumulation in the food chain, the precise detection of trace amounts of Hg2+ is essential for preventing chronic accumulation and ensuring food safety. In this study, we present a dual-mode paper sensor for simultaneous colorimetric and Surface-Enhanced Raman Spectroscopy (SERS) detection of Hg2+ in tea, achieving ultrasensitive, rapid, and on-site screening. 4-Mercaptopyridine (4-MPY) was effectively chemisorbed onto the gold nanoparticles (AuNPs), acting as a signal probe for colorimetric methods. Moreover, it can produce plasmonic hot spots for SERS by interacting with the pyridine ring. To enhance the signal intensity of both colorimetry and SERS, a silver shell is in-situ grown on the surface of AuNPs captured on the paper sensor by reduction of Ag+, achieving signal amplification. The visual limit of detection (LOD) for the colorimetric biosensor is 2.5 pM, while the LOD of SERS is 0.48 pM with this dual-mode paper sensor. The sensitivity of both the colorimetric method and SERS was improved by approximately 200 and 500 times, respectively, with the designed signal amplification strategy. The system allows for multiple parallel screening of the same sample, ensuring accurate results without any false-positive or false-negative. This study provides a valuable platform for the accurate detection of various other heavy metal ions and provides effective strategies for improving the performance of colorimetric methods.

Rapid and direct detection of m6A methylation by DNAzyme-based and smartphone-assisted electrochemical biosensor

m6A methylation detection is crucial for understanding RNA functions, revealing disease mechanisms, guiding drug development and advancing epigenetics research. Nevertheless, high-throughput sequencing and liquid chromatography-based traditional methods still face challenges to rapid and direct detection of m6A methylation. Here we report a DNAzyme-based and smartphone-assisted electrochemical biosensor for rapid detection of m6A. We initially identified m6A methylation-sensitive DNAzyme mutants through site mutation screening. These mutants were then combined with tetrahedral DNA to modify the electrodes, creating a 3D sensing interface. The detection of m6A was accomplished by using DNAzyme to capture and cleave the m6A sequence. The electrochemical biosensor detected the m6A sequence at nanomolar concentrations with a low detection limit of 0.69 nM and a wide detection range from 10 to 104 nM within 60 min. As a proof of concept, the 3′-UTR sequence of rice was selected as the m6A analyte. Combined with a smartphone, our biosensor shows good specificity, sensitivity, and easy-to-perform features, which indicates great prospects in the field of RNA modification detection and epigenetic analysis.

Metabolic engineering-enabled dual-color biosensor for discriminative and sensitive detection of toxic lead and mercury in environmental waters

The ubiquity of toxic heavy metals, particularly lead (Pb) and mercury (Hg), in environmental waters severely threatens ecosystems and human health. We developed a metabolic engineering-based dual-color bacterial biosensor for the sensitive and discriminative detection of Pb(II) and Hg(II) at nanomolar levels. The biosensor leverages the synthetic biology approach to integrate two pigments, prodeoxyviolacein (PDV) and deoxyviolacein (DV), into a single construct that responds distinctly to Pb(II) and Hg(II), respectively. The engineered E. coli biosensor exhibits a detection range of 0.732–3000 nM for Pb(II) and 0.183–750 nM for Hg(II), with low detection limits of 0.732 nM for Pb(II) and 0.183 nM for Hg(II). The biosensor demonstrated high sensitivity, selectivity, and accuracy with a recovery rate close to 1 in freshwater and seawater matrices. Notably, the biosensor's visual readout allows for rapid, equipment-free assessment. It is a practical tool for real-world monitoring of heavy metal pollution, especially in remote or resource-limited settings. This study underscores the potential of whole-cell biosensors as a sustainable and effective alternative to traditional heavy metal detection methods.

Shedding Light on Cellular Secrets: A Review of Advanced Optical Biosensing Techniques for Detecting Extracellular Vesicles with a Special Focus on Cancer Diagnosis.

In the relentless pursuit of innovative diagnostic tools for cancer, this review illuminates the cutting-edge realm of extracellular vesicles (EVs) and their biomolecular cargo detection through advanced optical biosensing techniques with a primary emphasis on their significance in cancer diagnosis. From the sophisticated domain of nanomaterials to the precision of surface plasmon resonance, we herein examine the diverse universe of optical biosensors, emphasizing their specified applications in cancer diagnosis. Exploring and understanding the details of EVs, we present innovative applications of enhancing and blending signals, going beyond the limits to sharpen our ability to sense and distinguish with greater sensitivity and specificity. Our special focus on cancer diagnosis underscores the transformative potential of optical biosensors in early detection and personalized medicine. This review aims to help guide researchers, clinicians, and enthusiasts into the captivating domain where light meets cellular secrets, creating innovative opportunities in cancer diagnostics.

Al-Doped CuS Colloidal Nanocrystals as a Highly Efficient Electrochemiluminescence Emitter for the Ultrasensitive Detection of Circulating Tumor DNA.

Herein, CuS colloidal nanocrystals (NCs) with adjustable band gap and good film forming ability have been synthesized as new ECL materials. Furthermore, the band gap and oxygen vacancy (OV) content of CuS NCs are regulated by Al3+ doping, which significantly improves the ECL response of CuS NCs. First, the band gap of CuS-Al NCs decreases after doping with Al3+, which makes it easier for electrons to transition across the band gap. At the same time, the oxygen vacancy of CuS-Al NCs increases, which is conducive to improving the conductivity and promoting charge transfer, thus improving the ECL performance of CuS-Al NCs. Circulating tumor DNA (ctDNA) is an important tumor marker, and its sensitive monitoring is of great significance for tumor diagnosis, treatment, and prognosis detection. Therefore, an ECL biosensor for ultrasensitive detection of circulating tumor DNA (ctDNA) was prepared by using CuS-Al NCs as luminescent material and combining multiple antidromic hybrid chain reaction (anti-HCR) strategy mediated by the target. Compared with the process of target-induced HCR generation, this strategy first forms multiple HCR products and then destroys the already formed HCR products by target-induced destruction, which enhances the sensitivity of target response and improves the reaction efficiency. The constructed biosensor has good detection performance, and the detection limit is as low as 2.74 aM. This work puts forward the luminescence phenomenon of colloidal nanocrystals as new ECL materials, which broadens the application of ECL technology in ultrasensitive biochemical detection.

Advancing SARS‐CoV‐2 Variant Detection with High Affinity Monoclonal Antibodies and Plasmonic Nanostructure

AbstractA nanoplasmonic biosensor for the precise detection of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) by leveraging advances in nanostructured sensing materials and highly selective monoclonal antibodies is presented. The sensor integrates plasmonic Au nanostructures optimized for surface‐enhanced Raman scattering (SERS), enhancing sensitivity through unique light interactions at the nanoscale. Coupled with exclusive antibodies that specifically target SARS‐CoV‐2 and its evolving variants, this sensor demonstrates remarkable selectivity and versatility. Validated with 270 clinical samples, it demonstrates a sensitivity of 98.9% and specificity of 100%. More importantly, the virus in nasopharyngeal swab samples collected over 3 years, marking the long‐term, large‐scale clinical validation of the nanoplasmonic biosensor for SARS‐CoV‐2 is been successfully detected. Furthermore, the integration of this sensor with face masks enables the detection of airborne SARS‐CoV‐2, highlighting its potential for routine management of coronavirus disease 2019 (COVID‐19).

Ligation-driven hyperbranched DNA assembly for label-free and sequence-specific measurement of RNA N6-methyladenosine in human breast tissues

N6-methyladenosine (m6A) is a critical post-transcriptional regulator, and it is linked to various biological functions (e.g., degradation, export, and translation) and multiple human diseases (e.g., cancers, immune disorders, and neurodegenerative diseases). The current methods for sequence-specific detection of m6A usually suffer from radioactive risk, large sample consumption, washing/separation steps, and false-positive signal. Herein, we develop a ligation-driven hyperbranched DNA assembly-based fluorescent biosensor for label-free and sequence-specific detection of m6A. In this assay, the unmethylated RNA can be identified and cleaved by m6A-sensitive endoribonuclease MazF. The retained intact m6A-RNA is complementary to the padlock probe to form a circular DNA, subsequently initiating ligation-driven hyperbranched rolling circle amplification (HRCA). The obtained HRCA products can be simply quantified with SYBR Gold as a fluorescent indicator. This method can be homogeneously carried out in an isothermal, label-free and antibody-free manner. The limit of detection can reach 0.079 pM. Moreover, this method can differentiate even 0.01 % m6A level in excess coexisting interferences, monitor cellular m6A RNA level with single-cell sensitivity, and differentiate m6A level in breast tumor tissues and normal adjacent tissues, with promising applications in m6A-releated epigenetic research and clinical diagnosis.

Split Gate Bulk-Planar Junctionless FET-Based Biosensor for Label-Free Detection of Biomolecules

Split Gate Bulk-Planar Junctionless FET-Based Biosensor for Label-Free Detection of Biomolecules

Ecofriendly approaches to efficiently enhance catalase performance

The present work reports on two approaches to enhance catalase (CAT) activity and its stability by using two simple, green processes. In the first procedure, CAT was transiently exposed to an ionic liquid (IL) in the presence of redox molecules related to CAT structure which resulted in partial denaturation. The other method, which uses high hydraulic pressure (HHP) to partially denature CAT (in the presence of redox molecules), has the advantage of being completely reagentless. In both cases, partial denaturation was followed by dialysis, hence refolding and entrapment of redox molecules within the modified 3-D CAT structure (affording a “wired” enzyme). The two approaches to enzyme “wiring” are discussed comparatively from the point of view of the parameters used during the procedure, residual enzyme activity, nature of the modifier, interaction between CAT and the redox molecules, antioxidant activity, and stability over time of the modified protein. Samples of CAT modified in the presence of iron sulfate heptahydrate from each series, respectively, were used to make enzyme electrodes which were tested as amperometric biosensors for hydrogen peroxide detection. Both showed catalytic effect and linear behavior and have potential for applications in the food industry, pharmaceuticals and the textile industry.

Harnessing gold nanomaterials for advanced multicolor colorimetric biosensors in food hazards detection

Harnessing gold nanomaterials for advanced multicolor colorimetric biosensors in food hazards detection

CRISPR/Cas12a and Hybridization Chain Reaction-Coregulated Magnetic Relaxation Switching Biosensor for Sensitive Detection of Viable Salmonella in Animal-Derived Foods.

We combined a CRISPR/Cas12a system with a hybridization chain reaction (HCR) to develop an ultrasensitive magnetic relaxation switching (MRS) biosensor for detecting viable Salmonella typhimurium (S. typhimurium). Magnetic nanoparticles of two sizes (30 and 1000 nm: MNP30 and MNP1000, respectively) were coupled through HCR. The S. typhimurium gene-activated CRISPR/Cas12a system released MNP30 from the MNP1000-HCR-MNP30 complex through a trans-cleavage reaction. After magnetic separation, released MNP30 was collected from the supernatant and served as a transverse relaxation time (T2) signal probe. Quantitative detection of S. typhimurium is achieved by establishing a linear relationship between the change in T2 and the target gene. The biosensor's limit of detection was 77 CFU/mL (LOD = 3S/M, S = 22.30, M = 0.87), and the linear range was 102-108 CFU/mL. The accuracy for detecting S. typhimurium in real samples is comparable to that of qPCR. Thus, this is a promising method for the rapid and effective detection of foodborne pathogens.

Ultrasensitive electrochemical biosensor for bacteria detection based on Fe3O4@COF-AuNPs and trigging isothermal circular amplification

Foodborne bacterial infections pose serious threats to human health, leading to illnesses and even fatalities. The key to solve this problem is to develop fast and effective sensor for sensitive detection of bacteria. In this study, an electrochemical biosensor based on magnetic nanocomposite material Fe3O4@COF-AuNPs and trigging isothermal circular amplification (TICA) was constructed for detection of foodborne bacteria. In this design, a hairpin aptamer probe (HAP)-bound DNA monolayer was designed, serving as the substrate for the electrode to increase surface area. The Escherichia coli (E. coli) was selected as the target. The presence of E. coli caused the configuration change of the HAP and allowed the occurrence of TICA with the use of the Klenow Fragment polymerase (KF-Poly), thus the HAPs were away from the DNA monolayer. After adding the catalytic magnetic nanocomposite material Fe3O4@COF-AuNPs, it was immobilized on the DNA monolayer of the electrode through DNA complementary pairing and exhibited high electrocatalytic behavior towards the reduction of 4-nitrophenol. This enabled ultrasensitive detection of E. coli, with the detection limit (LOD) as low as 10 CFU/mL. The detection time was 1 h. This designed electrochemical sensor showed high selectivity, stability, and reproducibility, which offered a new avenue for detection of foodborne bacteria.

Utilization of the dialysate to characterize dialysis adequacy by using microwave urea biosensor based on complementary split-ring resonator (CSRR)

The aim of this study is going to develop a monitoring approach for measuring blood urea concentration. This method uses microwave technology and complementary split-ring resonator (CSRR) to assess dialysis adequacy. The robust electric field near CSRR sides produces a high-sensitivity surface to a change in the nearby urea level. The proposed biosensor detection range spans from 1 to 100 mg/dL by modifying resonance frequency and peak attenuation. The biosensor was developed to operate at the main resonance frequency of 2.4 GHz, but all harmonics within the frequency range of 1–10 GHz were analyzed. A container incorporates the dialysate as the material being tested on the top of the sensor. Accurate measurement of blood urea variations using spent dialysate compared to the blood-based method has benefits due primarily to the lack of repetitive blood sampling. The innovative biosensor offers a non-invasive and convenient method to accurately evaluate the quantitative urea concentration in spent dialysate without the necessity of disposable chemicals. The biosensor has been designed to possess noteworthy attributes such as detecting minuscule concentration variations, low-cost fabrication, compact size, high sensitivity, and its ability to provide real-time results. By merging these features, the sensor demonstrates remarkable potential for non-invasively monitoring blood urea levels while seamlessly integrating with other dialysis devices. The initiative purpose of this study is going to offer renal patients methods for assessing dialysis adequacy with minimal impact on human health.

Multifunctional spatial-potential resolved electrochemiluminescence biosensor for dual-channel simultaneous detection of hepatitis A virus and hepatitis C virus DNA

Highly sensitive simultaneous detection of dual-target is one of the main research directions of electrochemiluminescence (ECL), but the traditional three-electrode system makes it difficult to realize this aim. This work designed a multifunctional spatial-potential resolved ECL biosensor for dual-channel simultaneous detection of hepatitis A virus (HAV) and hepatitis C virus (HCV) DNA. Self-luminescent dual-ligand metal organic framework (D-MOF) and cerium MOF (Ce-MOF) were modified on two parts of the ITO electrode to achieve dual-channel simultaneous detection. One ligand of D-MOF acted as the luminophore and the other as the co-reactant, so D-MOF could emit excellent positive potential ECL signal without requiring external co-reactants. In channel A, the Ag nanoparticles (Ag NPs) quenching probes were introduced to D-MOF through hybridization of HAV with “Y” type DNA. Positive potential signal of D-MOF was decreased for HAV DNA detection based on resonance energy transfer (RET). In channel B, the CdSe quantum dots (QDs) were introduced to Ce-MOF through hybridization of HCV with “Y” type DNA. Due to the excellent ECL performance of CdSe QDs, negative potential signal was increased for HCV DNA detection. In this work, an ingenious spatial-potential resolved ECL biosensor was developed for simultaneous detection of dual-target by simple sealing film isolation, which opened a new strategy for dual-target detection in general ECL assays with three-electrode system.

Sensing Interfaces Engineering for Organic Thin Film Transistors-Based Biosensors: Opportunities and Challenges.

Organic thin film transistors (OTFTs) enable rapid and label-free high-sensitivity detection of target analytes due to their low cost, large-area processing, biocompatibility, and inherent signal amplification. At the same time, the freedom of synthesis, tailorability, and functionalization of organic semiconductor materials and their ability to be combined with flexible substrates make them one of the ideal platforms for biosensing. However, OTFTs-based biosensors still face significant challenges, such as unexpected surface adsorption, disordered conformation, inhomogeneous graft density, and flexibility of probe molecules that biological sensing probes would face during immobilization. In this review, efficient immobilization strategies based on OTFTs biological sensing probes developed in the last 5 years are highlighted. First, the biosensors are classified according to their sensing interface. Second, a comprehensive discussion of the types of biological sensing probes is presented. Third, three commonly used methods for immobilizing biological sensing probes and their challenges are briefly described. Finally, the applications of OTFTs-based biosensors for liquid phase detection are summarized. This review provides a comprehensive and timely review of optimization in sensing interface engineering so that efficient immobilization of biological sensing probes with sensing interfaces will contribute to the development of high-performance OTFTs-based biosensors.

Cu2O nanoparticles with morphology-dependent peroxidase mimic activity: a novel colorimetric biosensor for deoxynivalenol detection.

Different morphological Cu2O nanoparticles including cube, truncated cube, and octahedron were successfully prepared by a selective surface stabilization strategy. The prepared cube Cu2O exhibited superior peroxidase-like activity over the other two morphological Cu2O nanoparticles, which can readily oxidize 3,3',5,5'-tetramethylbenzidine (TMB) to form visually recognizable color signals. Consequently, a sensitive and simple colorimetric biosensor was proposed for deoxynivalenol (DON) detection. In this biosensor, the uniform cube Cu2O was employed as the vehicle to label the antibody for the recognition of immunoreaction. The sensing strategy showed a detection limit as low as 0.01ng/mL, and a wide linear range from 2 to 100ng/mL. Concurrently, the approximate DON concentration can be immediately and conveniently observed by the vivid color changes. Benefiting from the high sensitivity and selectivity of the designed biosensor, the detection of DON in wheat, corn, and tap water samples was achieved, suggesting the bright prospect of the biosensor for the convenient and intuitive detection of DON in actual samples.

Yeast Surface-Displayed Quenchbody as a Novel Whole-Cell Biosensor for One-Step Detection of Influenza A (H1N1) Virus.

Timely surveillance of airborne pathogens is essential to preventing the spread of infectious diseases and safeguard human health. Methods for sensitive, efficient, and cost-effective detection of airborne viruses are needed. With advances in synthetic biology, whole-cell biosensors have emerged as promising platforms for environmental monitoring and medical diagnostics. However, the current design paradigm of whole-cell biosensors is mostly based on intracellular detection of analytes that can transport across the cell membrane, which presents a critical challenge for viral pathogens and large biomolecules. To address this challenge, we developed a new type of whole-cell biosensor by expressing and displaying VHH-based quenchbody (Q-body) on the surface of the yeast Saccharomyces cerevisiae for simple one-step detection of influenza A (H1N1) virus. Seventeen VHH antibody fragments targeting the hemagglutinin protein H1N1-HA were displayed on the yeast cells and screened for the H1N1-HA binding affinity. The functionally displayed VHHs were selected to create surface-displayed Q-body biosensors. The surface-displayed Q-body exhibiting the highest quenching and dequenching efficiency was identified. The biosensor quantitatively detected H1N1-HA in a range from 0.5 to 16 μg/mL, with a half-maximal concentration of 2.60 μg/mL. The biosensor exhibited high specificity for H1N1-HA over other hemagglutinin proteins from various influenza A virus subtypes. Moreover, the biosensor succeeded in detecting the H1N1 virus at concentrations from 2.4 × 104 to 1.5 × 107 PFU/mL. The results from this study demonstrated a new whole-cell biosensor design that circumvents the need for transport of analytes into biosensor cells, enabling efficient detection of the target virus particles.

Sensitive and selective fluorescence detection of acetamiprid using oxidized single-walled carbon nanohorns and cryonase-assisted signal amplification

To address the low accuracy of pesticide residue detection in traditional Chinese medicine, we developed a biosensor for acetamiprid detection. First, an oxidized single-walled carbon nanohorn capable of adsorbing and quenching fluorescence was prepared. Second, a novel fluorescence sensing system was constructed based on this nanomaterial. The detection performance of the sensor system was evaluated, which revealed that fluorescence quenching by the biosensor was primarily due to the adsorption of the aptamer by the nanomaterials. Optimal conditions were found to be a nanomaterial mass concentration of 800 ng/mL and an incubation time of 70 min, which resulted in the best fluorescence response. Under these optimal conditions, the system was used to detect acetamiprid residues in traditional Chinese medicine. The fluorescence intensity showed a strong linear relationship with acetamiprid concentration, with a correlation coefficient of 0.9985 and a detection limit of 6.33 ng/mL. In the sample test, the biosensor demonstrated high accuracy, with good average recovery rates and low relative standard deviation. The system showed excellent selectivity and detection performance, with no interference from other pesticides.

Engineering a PbrR-Based Biosensor for Cell-Free Detection of Lead at the Legal Limit.

Industrialization and failing infrastructure have led to a growing number of irreversible health conditions resulting from chronic lead exposure. While state-of-the-art analytical chemistry methods provide accurate and sensitive detection of lead, they are too slow, expensive, and centralized to be accessible to many. Cell-free biosensors based on allosteric transcription factors (aTFs) can address the need for accessible, on-demand lead detection at the point of use. However, known aTFs, such as PbrR, are unable to detect lead at concentrations regulated by the Environmental Protection Agency (24-72 nM). Here, we develop a rapid cell-free platform for engineering aTF biosensors with improved sensitivity, selectivity, and dynamic range characteristics. We apply this platform to engineer PbrR mutants for a shift in limit of detection from 10 μM to 50 nM lead and demonstrate use of PbrR as a cell-free biosensor. We envision that our workflow could be applied to engineer any aTF.

Mg2+- dependent six-jawed trap-mediated SERS biosensor for ratiometric detection of microRNA with use of the highly ordered Au NCs as substrate

Herein, a ratiometric surface-enhanced Raman scattering (SERS) biosensor was constructed with use of the highly ordered gold nanocubes (Au NCs) interface created by the liquid-phase assembly as substrate, and a novel Mg2+-dependent six-Jawed trap (SJT) cyclical amplification strategy for sensitive detection of microRNA 221 (miRNA-221). Impressively, in contrast to conventional gold nanoparticles (Au NPs), Au NCs with more sharp corners and edge characteristics can significantly improve the Raman signals of the Raman molecules, while the highly ordered Au NCs prepared by liquid-phase assembly can also increase the stability and repeatability of miRNA-221 detection. In addition, the newly constructed SJT with more Mg2+ shear sites were utilized to efficiently release plentiful output DNA with the Raman molecule methylene blue (MB) for greatly enhancing the sensitivity of the SERS biosensor. Ultrasensitive ratiometric SERS detection of miRNA-221 was realized by capturing the output DNA containing MB to generate ratiometric Raman signals at the sensing interface modified with Cyanine 5 (Cy5) Raman molecules. The SERS biosensor analyzed for miRNA-221 from 1 fM - 10 nM with an identification limit of 0.66 fM, and the approach is also effective for detecting miRNA-221 in cell lysates. Notably, the SJT signal amplification strategy utilized in this study makes it easier to create extremely sensitive biosensors and opens up new avenues for early detection of hepatocellular carcinoma cells (HCC).