Self-Assembly Multivalent Fluorescence-Nanobody Coupled Multifunctional Nanomaterial with Colorimetric Fluorescence and Photothermal to Enhance Immunochromatographic Assay

Abstract

The multimodal lateral flow immunoassay (LFIA) has provided accurate and reliable results for fast and immediate detection. Nonetheless, multimodal LFIA remains challenging to develop biosensors with high sensitivity and tolerance to matrix interference in agro-food. In this study, we developed a self-assembled multivalent fluorescence-nanobody (Nb26-EGFP-H6) with 16.5-fold and 30-fold higher affinity and sensitivity than a monovalent nanobody (Nb26). Based on the Nb26-EGFP-H6, we synthesized enhanced immune-probes Zn-CN@Nb26-EGFP-H6 by pyrolyzing and oxidizing an imidazolating zeolite framework-8 (ZIF-8) to obtain photothermal metal–carbon nanomaterials (Zn-CN) for immobilizing Nb26-EGFP-H6. The rough and porous structure of Zn-CN with a large surface area facilitates the enrichment and immobilization of antibodies. A trimodal lateral flow immunoassay (tLFIA) with colorimetric, fluorescent, and photothermal triple signal outputs was constructed for the detection of aflatoxin B1 (AFB1) in maize. Attractively, the Zn-CN-based tLFIA’s multiplex guarantees accurate and sensitive detection of AFB1, with triple signal detection limits of 0.0012 ng/mL (colorimetric signals), 0.0094 ng/mL (fluorescent signals), and 0.252 ng/mL (photothermal signals). The sensitivity of the trimode immunosensor was 628-fold and 42-fold higher than that of the original Nb26-based ELISA (IC50) and the unimodal LFIA (LOD). This work provides an idea for constructing a sensitive, tolerant matrix and efficient and accurate analytical platform for rapidly detecting AFB1 in food.

“Cave Effect” Induces Self-Assembled Bimetallic Hollow Structure for Three-in-One Lateral Flow Immunoassay

“…To verify the practicability of ZnCu 100 H-mAb, the constructed immune platform was applied to the actual samples of beef, milk, and honey, and the final recovery rate was determined by adding the standard samples method (1 × 10, 4 1 × 10, 3 2.5 × 10 2 CFU mL −1 ). The average recovery rate of CM-LFIA was 93.89%−131.25%, and the coefficient of variation (CV) was less than 6.16%.…”

“…Therefore, as infectious diseases sweep the globe, it was expected to be a tool for rapid screening of infections for early initial diagnosis and epidemic control . However, single-mode conventional gold nanoparticle detection was limited due to insufficient colorimetric brightness and low sensitivity . In contrast, multimodal detection involved two or more modes that were correlated with each other and amplified immune signals to obtain more sensitive and reliable experimental results than single-mode detection. − It not only had the advantages of traditional colorimetric mode but also introduced quantitative detection technology that can be substituted and complementary.…”

“…The multimode LFIA detection can output signals of different functions through nanomaterials (quantum dots, nanomases, metal–organic frameworks, , etc.) and specific antibodies (monoclonal antibodies, polyclonal antibodies, nanoantibodies), which mainly include colorimetric signal, fluorescence signal, photothermal signal, catalytic signal, electrochemical signal and surface-enhanced Raman scattering (SERS) signal, providing more sensitive quantitative analysis results. The multimode signal output was mainly obtained by the excellent characteristics of nanomaterials themselves, as an important part of LFIA, nanomaterials directly affected the sensitivity of detection. ,, Therefore, it was imperative to develop a multifunctional nanomaterial for the LFIA to improve the sensitivity.…”

Development of an Open Droplet Microchannel-Based Magnetosensor for Immunofluorometric Assay of Trimethoprim in Chicken and Pork Samples with a Wide Linear Range

“…However, microfluidic immunosensors that have been constructed still need to address certain significant issues, namely, the accessibility of signal inputs, the type of data collection, and the complexity of signal processing. According to the signal output mechanism, colorimetric, fluorescent, and electrochemical signal systems are the most commonly reported readout devices for immunoassay techniques. , Because fluorescence signal readout immunoassay technology has inherent advantages over colorimetric and absorbance-based analysis, including nondestructive mode of operation, rapid signal generation, high sensitivity, and selectivity, fluorescence immunosensors have become the most widely used and widely applied immunosensors. , Nevertheless, the majority of fluorescent immunosensors still have various limitations, including the requirement for complex signal response procedures, biotoxicity, strong fluorescent backgrounds, high light signal susceptibility, and inadequate homogeneity . Therefore, the conversion of the fluorescent signal to a grayscale output may further improve the detection performance, such as the sensor’s detection range and the signal output’s stability, by reducing the sensitivity of the signal. − In addition, the coupled magnetic bead mode improves and broadens the linear range, while simplifying immunoassay procedures and effectively avoiding background interference.…”

Fortified Dual-Spectral Overlap with Enhanced Colorimetric/Fluorescence Dual-Response Immunochromatography for On-Site Bimodal-Type Gentamicin Monitoring

“…Although the analytical performance in aforementioned technologies is satisfactory, specialized staff, lengthy procedures, and cumbersome pretreatment fail to satisfy the ever-increasing requirements of on-site surveillance concerns, especially for the emergency cases in poor economies and developing countries . Moreover, results of lacking relatively independent second signal-mediated built-in correction in the traditional single detection mode are susceptible to interference by the actual test environment. − In this sense, an accurate, rapid, and real-time detection method with a bimodal-type signal output pattern suitable for novice users and low-tech environments is an urgent objective within the actual point-of-care (POC) industry.…”