Lateral flow biosensing for low abundance detection of brain natriuretic peptide with enzyme-free amplification

Zhang, Menghan (2025) Lateral flow biosensing for low abundance detection of brain natriuretic peptide with enzyme-free amplification. PhD thesis, University of Glasgow.

Abstract

The diagnosis of heart failure in emergency settings requires rapid and sensitive detection of brain natriuretic peptide (BNP), a low-abundance biomarker of heart failure with a clinical ruleout threshold of 100 pg/mL (0.03 nM). The current gold standards for BNP testing in clinical practice all rely on immunoassays that necessitate cold-chain storage for antibodies, limiting their utility at the point-of-care (POC). This thesis presents the development and optimisation of a DNA-based BNP assay integrating a dual-aptamer recognition system with an enzyme-free and isothermal amplification circuit. The work systematically addressed key challenges in the design of this biosensing platform. Initial efforts focused on optimising the participating hairpin probes through thermodynamic and kinetic principles for leakage control and maximal amplification efficiency. This was followed by effective incorporation of two BNP-specific aptamers, demonstrating their utility in catalysing the reaction cascades upon target binding in a homogeneous, wash-free assay format. Finally, the system was adapted for lateral flow test (LFT) compatibility, achieving a binary response at the clinically relevant thresholds for BNP. Strategies to enhance the performance on LFTs, including dilution procedures, pre-treatment of the strips, and buffer optimisations, were investigated to improve robustness of the true signal while mitigating the background noise.

This research advances the field by combining the specificity of aptamers with the simplicity of LFTs, bridging the gap between lab-based immunoassays and POC needs. While limitations in aptamer affinity and reaction kinetics at trace concentrations highlight the areas for future improvement, the study offers a reliable and equipment-free alternative for heart failure diagnosis in resource-limited settings. The proposed future directions, including the exploration of a fully antibody-free microfluidic device and its multiplexing capability, underscore the versatility and translational potential of this novel and promising approach for timely diagnostics and monitoring of heart failure.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Additional Information: Due to copyright issues this thesis is not available for viewing.
• Subjects: Q Science > QD Chemistry; Q Science > QR Microbiology; R Medicine > R Medicine (General); T Technology > T Technology (General)
• Colleges/Schools: College of Science and Engineering > School of Engineering > Biomedical Engineering
• Supervisor's Name: Reboud, Professor Julien and Cooper, Professor Jon
• Date of Award: 2025
• Depositing User: Theses Team
• Unique ID: glathesis:2025-85639
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 04 Dec 2025 13:50
• Last Modified: 04 Dec 2025 13:50
• URI: https://theses.gla.ac.uk/id/eprint/85639