Ultrasensitive Electrochemiluminescence Biosensing Platform Based on Polymer Dots with Aggregation-Induced Emission for Dual-Biotoxin Assay.

Multitarget assay has always been a hot topic in electrochemiluminescence (ECL) methods. Herein, a "on-off-on" ECL aptasensor was developed for the ultrasensitive and sequential detection of possible biological warfare agents, deoxynivalenol (DON) and abrin (ABR). As a luminophore, polymer dots (Pdots) with aggregation-induced emission exhibit high ECL efficiency in the aptasensor, i.e., the signal "on" state. The DON assays mainly depend on ECL quenching due to the efficient quenching effect between ferrocene-H2-ferrocene (Fc-H2-Fc) and Pdots, i.e., the signal "off" state. When the aptasensor is incubated with the oligonucleotide sequence S2 to replace Fc-H2-Fc, obvious ECL recovery occurs, i.e., the signal "on" state, which can be used to sequentially detect ABR. The limit of detection (LOD) for DON is 0.73 fg·mL-1 in the range of 5.0 to 50 ng·mL-1; and the LOD for ABR is ∼0.38 pg·mL-1 in the range of 1.25 pg·mL-1 to 1.25 µg·mL-1. The as-designed ECL aptasensor exhibits good stability and reproducibility, high specificity, and favorable practicality. Therefore, this work provides a new approach for assays of DON and ABR in food safety and can be used as a model to design an ultrasensitive ECL biosensor for multitarget detection.

A highly sensitive luminescent aptasensor utilizing MOF-74-co encapsulation of luminol in a 'turn-on' mode for streptomycin detection.

This study focused on detecting streptomycin (STR) residues using a luminescent aptasensor encapsulated with aptamer. Utilizing MOF-74-Co with peroxidase-like activity, luminol was enclosed in its pores. The specific STR aptamer acted as a gatekeeper, ensuring excellent performance. Upon exposure to STR, the aptamers detached, releasing luminol and amplifying the luminescent signal through MOF-74-Co catalytic activity. A linear relationship between fluorescence intensity and STR concentration (50 nM âˆ¼ 5 × 106 nM) was established, with a limit of detection of 0.065 nM. The sensor exhibited high selectivity for STR even in the presence of other aminoglycoside antibiotics. Applied to tea, egg, and honey samples, the sensor showed recovery rates of 91.38-100.2%, meeting safety standards. This MOF-based aptasensor shows promise for detecting harmful residues.

A novel photoelectrochemical aptasensor based on 3D flower-like g-C3N4/BiOI p-n heterojunction for the sensitive detection of kanamycin.

BACKGROUND: Kanamycin (KAN) residues in animal-derived foods continuously enter the human body, which will pose serious threats to human health such as hearing loss, nephrotoxicity and other complications. Therefore, to sensitively detect KAN residues by a reliable technology is extremely urgent in food quality and safety. Compared with traditional methods being limited by cost and complexity, photoelectrochemical (PEC) biosensors benefit from some merits such as rapid response, excellent sensitivity and good stability. In this study, the construction of a highly efficient PEC platform to realize KAN residues detection is discussed. RESULTS: Herein, a novel p-n heterojunction consisting of flower-like BiOI microspheres and graphite carbon nitride (g-C3N4) nanoflakes was developed to establish a PEC aptasensor for KAN detection at 0 V. The prepared g-C3N4/BiOI heterostructure showed not only significantly enhanced PEC activity due to the larger specific surface area but also greatly increased charge separation efficiency owing to the strong internal electric field. Meanwhile, using g-C3N4/BiOI as a highly efficient photoactive material for binding amine-functionalized aptamers to capture KAN, the photocurrent signals showed a 'turn off' mode to achieve the sensitive detection of KAN. The proposed PEC aptasensor exhibited linear response for KAN from 5 × 10-9 to 3 × 10-7 mol L-1 with a low detection limit of 1.31 × 10-9 mol L-1, and satisfactory recoveries (97.44-107.38 %) were obtained in real food samples analysis. SIGNIFICANCE: This work presented a novel p-n heterojunction-based PEC aptasensor with strong selectivity and stability, rendering it allowed to detect KAN in animal-derived foods including milk, honey and pork. Additionally, the detection range satisfied the MRLs for KAN specified by the national standards, demonstrating the potential application for food analysis. The study provides a new insight into the development of efficient and practical biosensors for antibiotic residues detection.

Stable detection of diazinon residues in vegetables by an electrochemiluminescent aptasensor based on the in-situ production of H2O2 from dual-catalytic glucose.

Stable detection of diazinon (DZN) residues in vegetables is important for food safety. In this work, an electrochemiluminescence (ECL) aptasensor with dual-catalytic glucose in-situ production of H2O2 was constructed for the stable detection of DZN in vegetables. Firstly, MWCNTs@MB was prepared using π-π stacking interactions between methylene blue (MB) and multi-walled carbon nanotubes (MWCNTs) to enhance the loading of MB on an electrode and thus catalyze the generation of H2O2 from glucose. Secondly, Cu2O@AuNPs was formed by loading AuNPs on the surface of Cu2O through spontaneous reduction reaction, which improved the interfacial charge transfer, Cu2O nano-enzyme had glucose oxidase mimicking activity and could further catalyze the production of more H2O2 from glucose. MWCNTs@MB and Cu2O@AuNPs played a key role in the in-situ generation of co-reacting reagent H2O2, which solved the problem of unstable detection caused by the easy decomposition of the H2O2 solution added to the luminescence system. In addition, the aptamer was immobilized on the electrode surface by forming Au-S bonds with Cu2O@AuNPs. As a result, the ECL aptasensor performed good linearity in 1.00 pg mL-1-1.00 µg mL-1 and a low limit of detection (LOD) to 0.39 pg mL-1 (S/N = 3). This work provided an effective method for the accurate and stable detection of DZN residues in vegetables, which was of great significance in ensuring food safety and assessing the environmental risk of DZN.

Aptamer molecular gate functionalized mesoporous SiO2@MB controlled-release system for pollutant detection using Ti(â ¢) self-doped TiO2 NTs as active photoanode coupled with electrostatic modulation.

Atrazine (ATZ) is a widely used herbicide that can cause serious harm to organisms and ecosystems. An immobilization-free photoelectrochemical (PEC) aptasensor has been herein developed for ATZ based on aptamer molecular gate functionalized mesoporous SiO2@MB controlled release system. Compared with traditional immobilization-based sensors, immobilization-free sensors (IFSs) avoid the modification of the recognition element on the electrode surface. Mesoporous SiO2 with large surface area and good biocompatibility can be used as nanocontainers to stably encapsulate the signal shuttle molecule methylene blue (MB). The bifunctional aptamer (APT) is used not only as the recognition element for ATZ but also as the signal switch to block or release MB. In the presence of ATZ, the specific recognition between ATZ and APT will cause the detachment of APT from the surface of SiO2, thus the molecular gate will open and release MB. Due to pH modulation, the positively charged MB can reach the surface of the negatively charged Ti(III) self-doped TiO2 NTs (Ti(III)-TiO2 NTs) electrode to act as an electron donor, which increases the photocurrent. The immobilization-free aptasensor has shown ultrasensitive detection of ATZ with a wide linear range from 1.0 pM to 100.0 nM and a low detection limit of 0.1 pM. In addition, the sensor has excellent selectivity, stability and anti-interference ability, and has been used in real water sample analysis successfully. This strategy has provided a new idea for the design of advanced immobilization-free PEC sensors for environmental pollutant detection.

Dual emitting aggregation-induced electrochemiluminescence from tetrastyrene derivative for chloramphenicol detection.

Chloramphenicol (CAP) poses a threat to human health due to its toxicity and bioaccumulation, and it is very important to measure it accurately and sensitively. This work explored a host-guest recognition strategy to mediate dual aggregation-induced electrochemiluminescence (AIECL) of 1,1,2,2-tetrakis(4-(pyridin-4-yl) phenyl)-ethene (TPPE) for ratio detection of CAP, in which, cucurbit[8]uril (CB[8]) served as host to assemble guest TPPE. The resulting supramolecular complex CB[8]-TPPE exhibited excellent dual-AIECL-emission with signal strength approximately four times that of TPPE aggregates and black hole quencher-1 (BHQ1) could efficiently quench dual-AIECL signal. CB[8]-TPPE coupled dual-function quencher BHQ1 and high-efficiency DNA reactor to achieve ultra-sensitive detection of CAP, exhibiting a linearity range of 10 fmol·L-1-100 nmol·L-1 and limit of detection of 1.81 fmol·L-1. CB[8]-TPPE provides a novel way to improve the dual-emission of TPE derivatives and sets up a promising platform for CAP detection, demonstrating a good practical application potential.

Structure of plasmonic multi spectral Apta sensor and analyzing of bulk and surface sensitivity.

In this work, a multispectral aptasensor structure, including a sub-layer and two side walls, was presented. The cells are positioned at the down and top of the structure, with the down cells oriented perpendicular to the walls and the top cells aligned parallel to the walls. The validity of the findings was verified by the utilization of a numerical simulation technique known as 3D Finite Difference Time Domain (FDTD). The biosensor under consideration exhibits sensitivities of 1093.7 nm/RIU, 754 nm/RIU, and 707.43 nm/RIU in mode III, mode II, and mode I, respectively. In the majority of instances, the quantity of analyte available is insufficient to coat the surface of the sensor thoroughly. Consequently, in this study, the evaluation of surface sensitivity was undertaken alongside bulk sensitivity. The surface sensitivity of the suggested structure for mode II in the sensor layer, with thicknesses of 10, 20, 30, and 70 nm, is measured to be 25, 78, 344, and 717.636 nm/RIU, respectively. Our design incorporates a unique arrangement of sub-layer and side walls, with cells positioned to maximize interaction with the target analyte. This innovative configuration, combined with Ag for its superior plasmonic properties, enables the detection of E. coli O157 with remarkable sensitivity.

Breast cancer detection based on cancer antigen 15-3; emphasis on optical and electrochemical methods: A review.

Cancer antigen 15-3 (CA 15-3) is a crucial marker used in the diagnosis and monitoring of breast cancer (BC). The demand for early and precise cancer detection has grown, making the creation of biosensors that are highly sensitive and specific essential. This review paper provides a thorough examination of the progress made in optical and electrochemical biosensors for detecting the cancer biomarker CA 15-3. We focus on explaining their fundamental principles, sensitivity, specificity, and potential for point-of-care applications. The performance attributes of these biosensors are assessed by considering their limits of detection, reaction times, and operational stability, while also making comparisons to conventional methods of CA 15-3 detection. In addition, we explore the incorporation of nanomaterials and innovative transducer components to improve the performance of biosensors. This paper conducts a thorough examination of recent studies to identify the existing obstacles. It also suggests potential areas for future research in this fast progressing field.The paper provides insights into their advancement and utilization to enhance patient outcomes. Both categories of biosensors provide significant promise for the detection of CA 15-3 and offer distinct advantages compared to conventional analytical approaches.

Dual-sensitized heterojunction Ag2S/ZnS/NiS composites with entire visible-light region absorption for ultrasensitive photoelectrochemical detection of tobramycin.

In this study, an ultrasensitive photoelectrochemical (PEC) aptasensor based on dual-sensitized heterojunction Ag2S/ZnS/NiS composites as a signal probe was proposed for the detection of tobramycin (TOB) by combining a cascaded quadratic signal amplification strategy. Specifically, compared to the limited visible light-harvesting capability of single sensitized composites, Ag2S/ZnS/NiS composites with p-n and n-n heterojunction could greatly improve the light energy utilization to tremendously strengthen the optical absorption in the entire visible-light region. Moreover, dual-sensitized heterojunction could effectively hinder the rapid recombination of photoelectrons and holes (carriers) to obtain a good photocurrent for improving the sensitivity of the aptasensor. Furthermore, a cascaded quadratic signal amplification strategy was applied to convert trace target TOB into plentiful gold nanoclusters (Au NCs) labelled double-stranded DNA for the construction of PEC aptasensor, with a broad linear detection range from 0.01 to 100 ng mL-1 and a low detection limit of 3.38 pg mL-1. Importantly, this study provided a versatile and sensitive PEC biosensing platform for TOB analysis, and demonstrated its successful application for TOB detection in milk samples. This protocol provides a novel dual-sensitized heterojunction composites to develop a highly efficient and harmfulless PEC aptasensor, which is expected to be used in food safety, environmental monitoring and other areas.

Aptamer-based electrochemical nanobiosensor for research and monitoring of multiple sclerosis in mice models.

Multiple sclerosis (MS) is a severe progressive autoimmune-inflammatory, demyelinating process in the central nervous system (CNS) with heterogeneous neurological symptoms appearing as a consequence of myelin break down. Myelin basic protein (MBP) makes up to 30 % of the CNS myelin [1] and it is known to be released into the cerebrospinal fluid (CSF) as a bioindicator of MS. Autoimmune encephalomyelitis (EAE) is a mice model of MS widely used for research and development of new treatments [2]. Herein, MBP specific aptamer developed for possible therapeutic purposes in mouse model [3] was applied as a bioreceptor for MBP recognition. A nanobiosensor for MBP detection and monitoring was developed by using graphene oxide (GO) nanoparticles integrated onto the screen-printed carbon electrodes (SPCE) and aptamer immobilized to create a bioactive layer on the sensor surface for MBP binding. The measurements were carried out using electrochemical impedance spectrometry (EIS). Validation studies were carried out in a biological matrix (artificial CSF) containing MBP, and MSA. The aptasensor had LOD in artificial CSF 0.01 ng/mL and showed its usability in the concentration range of 0.01 … 64 ng/mL.

Exo â ¢-assisted amplification signal strategy synergized with Au@Pt NFs/CoSe2 for sensitive detection of enrofloxacin.

Overuse of enrofloxacin (ENR) has posed a potential threat to ecosystems and public health, so it is critical to sensitive and accurate determination of ENR residues. In this work, a novel ultra-sensitive and specific electrochemical aptasensor was fabricated based on the cobalt diselenide loaded gold and platinum nanoflowers (Au@Pt NFs/ CoSe2) and Exonuclease III (Exo III)-assisted cycle amplification strategy for the detection of ENR. Au@Pt NFs/ CoSe2 nanosheets as the substrate material, with large surface area, accelerate electron transfer and attach more DNA probes on the electrode substrate, have effectively enhanced the electrochemical performance of the electrode. With the existence of Enrofloxacin (ENR), the aptamer recognizes and binds to ENR, thus the signal probe cDNA was released and immobilized onto the electrode surface to hybridized with methylene blue (MB) labelled DNA (MB-DNA), thereby triggering the Exo III-assisted cycle for further signal amplification. As expected, the prepared aptasensor demonstrated excellent sensitivity and selectivity, with a wide linear range from 5.0 × 10-6 ng/mL to 1.0 × 10-2 ng/mL for ENR, a low detection limit of 1.59 × 10-6 ng/mL. Consequently, this strategy provided a promising avenue for ultrasensitive and accurate detection of ENR in milk samples.

Detection of Tetracycline with a CRISPR/Cas12a Aptasensor Using a Highly Efficient Fluorescent Polystyrene Microsphere Reporter System.

CRISPR-based diagnostics use the CRISPR-Cas system trans-cleavage activity to identify specific target sequences. When activated, this activity cleaves surrounding reporter molecules, producing a detectable signal. This technique has great specificity, sensitivity, and rapid detection, making it an important molecular diagnostic tool for medical and infectious disease applications. Despite its potential, the present CRISPR/Cas system has challenges with its single-stranded DNA reporters, characterized by low stability and limited sensitivity, restricting effective application in complex biological settings. In this work, we investigate the trans-cleavage activity of CRISPR/Cas12a on substrates utilizing fluorescent polystyrene microspheres to detect tetracycline. This innovative discovery led to the development of microsphere probes addressing the stability and sensitivity issues associated with CRISPR/Cas biosensing. By attaching the ssDNA reporter to polystyrene microspheres, we discovered that the Cas12a system exhibits robust and sensitive trans-cleavage activity. Further work revealed that the trans-cleavage activity of Cas12a on the microsphere surface is significantly dependent on the concentration of the ssDNA reporters. Building on these intriguing discoveries, we developed microsphere-based fluorescent probes for CRISPR/Cas aptasensors, which showed stability and sensitivity in tetracycline biosensing. We demonstrated a highly sensitive detection of tetracycline with a detection limit of 0.1 µM. Finally, the practical use of a microsphere-based CRISPR/Cas aptasensor in spiked food samples was proven successful. These findings highlighted the remarkable potential of microsphere-based CRISPR/Cas aptasensors for biological research and medical diagnosis.

Development and characterization of a portable electrochemical aptasensor for IsdA protein and Staphylococcus aureus detection.

Staphylococcus aureus (S. aureus) is recognized as one of the most common causes of gastroenteritis worldwide. This pathogen is a major foodborne pathogen that can cause many different types of various infections, from minor skin infections to lethal blood infectious diseases. Iron-regulated surface determinant protein A (IsdA) is an important protein on the S. aureus surface. It is responsible for iron scavenging via interaction with hemoglobin, haptoglobin, and hemoglobin-haptoglobin complexes. This study develops a portable aptasensor for IsdA and S. aureus detection using aptamer-modified gold nanoparticles (AuNPs) integrated into screen-printed carbon electrodes (SPCEs). The electrode system was made of three parts, including a carbon counter electrode, an AuNPs/carbon working electrode, and a silver reference electrode. The aptamer by Au-S bonding was conjugated on the electrode surface to create the aptasensor platform. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were utilized to investigate the binding interactions between the aptasensor and the IsdA protein. CV studies showed a linear correlation between varying S. aureus concentrations within the range of 101 to 106 CFU/mL, resulting in a limit of detection (LOD) of 0.2 CFU/mL. The results demonstrated strong reproducibility, selectivity, and sensitivity of the aptasensor for enhanced detection of IsdA, along with about 93% performance stability after 30 days. The capability of the aptasensor to directly detect S. aureus via the IsdA surface protein binding was further investigated in a food matrix. Overall, the aptasensor device showed the potential for rapid detection of S. aureus, serving as a robust approach to developing real-time aptasensors to identify an extensive range of targets of foodborne pathogens and beyond.

Triblock polyadenine-based electrochemical aptasensor for ultra-sensitive detection of carcinoembryonic antigen via exonuclease III-assisted target recycling and hybridization chain reaction.

Carcinoembryonic antigen (CEA), a key colon biomarker, demands a precise detection method for cancer diagnosis and prognosis. This study introduces a novel electrochemical aptasensor using a triblock polyadenine probe for ultra-sensitive detection of CEA. The method leverages Exonuclease III (Exo III)-assisted target recycling and hybridization chain reaction. The triblock polyadenine probe self-assembles on the bare gold electrode through the strong affinity between adenine and gold electrode, blocking CEA diffusion and providing a large immobilization surface. CEA binding to hairpin probe 1 (HP1), followed by the hybridization between HP1 and hairpin probe 2 (HP2), triggers DNA cleavage by Exo III, amplifying the signal via a hybridization chain reaction and producing numerous dsDNA walkers that generates a dramatic electrochemical impedance signal. Under optimized conditions, the aptasensor achieved two ultra-low detection limits: 0.39 ag∙mL-1 within the concentration range of 5 ag∙mL-1 to 5 × 106 ag∙mL-1, and 1.5 ag∙mL-1 within the concentration range of 5 × 106 ag∙mL-1 to 1 × 1010 ag∙mL-1. Its performance in human serum samples meets the practical standards, offering a promising new tool for ultrasensitive tumor marker detection, potentially revolutionizing early cancer diagnosis.

Bismuthene - Tetrahedral DNA nanobioconjugate for virus detection.

In this work, we present an electrochemical sensor for fast, low-cost, and easy detection of the SARS-CoV-2 spike protein in infected patients. The sensor is based on a selected combination of nanomaterials with a specific purpose. A bioconjugate formed by Few-layer bismuthene nanosheets (FLB) and tetrahedral DNA nanostructures (TDNs) is immobilized on Carbon Screen-Printed Electrodes (CSPE). The TDNs contain on the top vertex an aptamer that specifically binds to the SARS-CoV-2 spike protein, and a thiol group at the three basal vertices to anchor to the FLB. The TDNs are also marked with a redox indicator, Azure A (AA), which allows the direct detection of SARS-CoV-2 spike protein through changes in the current intensity of its electrolysis before and after the biorecognition reaction. The developed sensor can detect SARS-CoV-2 spike protein with a detection limit of 1.74 fg mL-1 directly in nasopharyngeal swab human samples. Therefore, this study offers a new strategy for rapid virus detection since it is versatile enough for different viruses and pathogens.

Aptamer and Electrochemical Aptasensor towards Selenate Ions (SeO42-).

Selenium is an essential inorganic compound in human and animal nutrition, involved in the proper functioning of the body. As a micronutrient, it actively contributes to the regulation of various metabolic activities, i.e., thyroid hormone, and protection against oxidative stress. However, Se exhibits a narrow concentration window between having a positive effect and exerting a toxic effect. In higher doses, it negatively affects living organisms and causes DNA damage through the formation of free radicals. Increased reactivity of Se anions can also disrupt the integrity and function of DNA-repairing proteins. As the permissible concentration of Se in drinking water is 10 µg/L, it is vital to develop sensitive and robust methods of Se detection in aqueous samples. In this study, for the first time, we proposed a selective aptamer for selenate ion detection, chosen following the SELEX process, and its application in the construction of an electrochemical aptasensor towards SeO42- ions. Measurement conditions such as the used redox marker and pH value of the measurement solution were chosen. The proposed aptasensor is characterized by good selectivity and an LOD of 1 nM. Conditions for biosensor regeneration and storage were also investigated in this research.

Label-free electrochemical aptasensor for the detection of HepG2 hepatocellular carcinoma cells.

Hepatocellular carcinoma (HCC) is the most common liver malignancy and is characterized by increasing incidence and high mortality rates. Current methods for the screening and diagnosis of HCC exhibit inherent limitations, highlighting the ever-growing need for the development of new methods for the early diagnosis of HCC. The aim of this work was to develop a novel electrochemical aptasensor for the detection of HepG2 cells, a type of circulating tumor cells that can be used as biomarkers for the early detection of HCC. A carbon screen-printed electrode was functionalized with a composite suspension containing graphene oxide, chitosan, and polyaniline nanoparticles to increase the electrode surface and provide anchoring sites for the HepG2 cell-specific aptamer. The aptamer was immobilized on the surface of the functionalized electrode using multipulse amperometry, an innovative technique that significantly reduces the time required for aptamer immobilization. The innovative platform was successfully employed for the first time for the amplification-free detection of HepG2 cells in a linear range from 10 to 200,000 cells/mL, with a limit of detection of 10 cells/mL. The platform demonstrated high selectivity and stability and was successfully used for the detection of HepG2 cells in spiked human serum samples with excellent recoveries.

Advances in aptamer-based biosensors for monitoring foodborne pathogens.

Biosensors are analytical devices for detecting a wide range of targets, including cells, proteins, DNA, enzymes, and chemical and biological compounds. They mostly rely on using bioprobes with a high binding affinity to the target for specific detection. However, low specificity and effectiveness of the conventional biosensors has led to the search for novel materials, that can specifically detect biomolecules. Aptamers are a group of single-stranded DNA or RNA oligonucleotides, that can bind to their targets with high specificity and serve as effective bioprobes for developing aptamer-based biosensors. Aptamers have a shorter production time, high stability, compared to traditional bioprobes, and possess ability to develop them for specific target molecules for tailored applications. Thus, various aptasensing approaches, including electrochemical, optical, surface plasmon resonance and chip-dependent approaches, have been investigated in recent times for various biological targets, including foodborne pathogens. Hence, this article is an overview of various conventional foodborne pathogen detection methods, their limitations and the ability of aptamer-based biosensors to overcome those limitations and replace them. In addition, the current status and advances in aptamer-based biosensors for the detection of foodborne pathogens to ensure food safety were also discussed. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-023-05889-8.

Self-designed portable dual-mode fluorescence device with custom python-based analysis software for rapid detection via dual-color FRET aptasensor with IoT capabilities.

An innovative aptasensor incorporating MoS2-modified bicolor quantum dots and a portable spectrometer, designed for the simultaneous detection of ochratoxin A (OTA) and aflatoxin B1 (AFB1) in corn was developed. Carbon dots and CdZnTe quantum dots were as nano-donors to label OTA and AFB1 aptamers, respectively. These labeled aptamers were subsequently attached to MoS2 receptors, enabling fluorescence resonance energy transfer (FRET). With targets, the labeled aptamers detached from the nano-donors, thereby disrupting the FRET process and resulting in fluorescence recovery. Furthermore, a portable dual-mode fluorescence detection system, complemented with customized python-based analysis software, was developed to facilitate rapid and convenient detection using this dual-color FRET aptasensor. The developed host program is connected to the spectrometer and transmits data to the cloud, enabling the device to have Internet of Things (IoT) characteristics. Connected to the cloud, this IoT-enabled device offers convenient and reliable fungal toxin detection for food safety.

Optical Label-Free Aptasensor Based on Weak Value Amplification for Real-Time and Ultrasensitive Detection of IgE.

Allergy is a prevalent disease, and the potential allergic population is expanding with industrialization and changes in people's living standards. Serum immunoglobulin E (IgE) level is one of the critical indicators for determining allergy. Here, we proposed a simple, real-time monitoring, low chip cost, label-free aptamer biosensing strategy based on weak value amplification (WVA) for the quantitative detection of IgE in serum samples, enabling early and accurate diagnosis of allergic or hypersensitive patients. The aptasensor combined an imaging weak measurement system with the high specificity of the aptamer for the marker IgE. By modifying the amino group at the 3-terminal end, the anti-IgE aptamers can attach to a dopamine-modified prism's surface and selectively recognize IgE in human serum. In the presence of IgE, a specific binding reaction occurred, resulting in a change in the refractive index of the reactive region's surface, manifested as a change in the light intensity of the camera acquired experimental images. As the concentration of IgE increased, the relative light intensity advanced sequentially. The WVA-aptasensing strategy achieved a wide detection range of 0.01 ng/mL to 2 µg/mL in phosphate buffered saline buffer, with the resolution as low as 4.3 pg/mL. IgE testing experiments in human serum have proved the feasibility of our methods in detecting complex samples. In addition, the method specifically recognized IgE without interference from other proteins. We believe that our proposed sensing strategy opens up new possibilities for ultrahigh sensitivity screening of IgE and can be expanded to detecting other biomolecules.