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Updated: Aug 16, 2026
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Wide-field Fluorescent Microscopy and Fluorescent Imaging Flow Cytometry on a Cell-phone
Published on: April 11, 2013
A Label-Free Bioluminescent scFv-NLuc Fusion Probe Enabling a Smartphone-Based Sensitive Immunoassay Platform Using
Mingyue Ding1, Hao Wen1, Shixiang Wu1
1National Reference Laboratory of Veterinary Drug Residues (HZAU) and MOA Key Laboratory For the Detection of Veterinary Drug Residues, Huazhong Agricultural University, Wuhan, China.
Small (Weinheim an Der Bergstrasse, Germany)
|August 14, 2026
Summary
A new label-free assay uses engineered enzymes for rapid food contaminant detection. This method offers sensitive, field-deployable quantification of hazardous residues like lomefloxacin (LOM) in food.
Area of Science:
- Food Safety
- Analytical Chemistry
- Biotechnology
Background:
- Enzyme-labeled lateral flow immunoassays (LFIA) are used for food contaminant detection.
- Biological instability and complex chemical conjugation of enzyme labels limit high-throughput screening.
- A need exists for simplified, stable, and sensitive methods for detecting food contaminants.
Purpose of the Study:
- To develop a rapid, label-free platform for quantifying lomefloxacin (LOM) in food.
- To utilize an engineered immunoprobe with an intrinsic signal generator for enhanced assay performance.
- To enable sensitive, field-deployable detection of hazardous food residues.
Main Methods:
- An engineered immunoprobe combining a high-affinity single-chain variable fragment antibody (3G9-scFv) specific to LOM with Nanoluciferase (NLuc) was developed.
- Nanoluciferase (NLuc) was used as an intrinsic signal generator, catalyzing furimazine oxidation to produce bioluminescence.
- The label-free assay involved smartphone-based luminescence measurement for quantification.
- Homology modeling and molecular docking were used to elucidate the structural basis of the immunoprobe's functionality.
Main Results:
- The label-free assay demonstrated a limit of quantification of 0.12 ng/mL for LOM.
- A visual detection limit of 1 ng/mL was achieved.
- High accuracy and reproducibility were confirmed with recovery rates from 79.0% to 113.0% and coefficients of variation (CVs) between 2.3% and 10.9%.
- The label-free design eliminated conjugation variability and simplified protocol execution.
Conclusions:
- A novel, rapid, label-free luciferase-based platform was successfully developed for LOM quantification in food.
- The engineered immunoprobe with Nanoluciferase (NLuc) provides a stable and efficient intrinsic signal generator.
- This system offers a promising solution for sensitive, high-throughput screening and monitoring of hazardous residues in food safety applications.
