An interdisciplinary team of researchers at Washington University have developed a sensitive, shelf-stable, label-free system for quickly quantifying biomarkers in point-of-care settings (e.g., office, ambulance or battlefield). Localized surface plasmon resonance (LSPR) offers a powerful approach for cost-effective lab-on-chip point-of-care diagnostics. However, LSPR typically detects biomarkers using antibodies that are costly to generate; have limited sensitivity due to their large size; and have limited pH and temperature stability, . This technology solves those problems by replacing antibodies with stable, highly specific aptamer/peptide recognition elements. This system was demonstrated by using gold plasmonic nanotransducers conjugated with aptamers to detect the cardiac biomarker troponin I. This technology offers a platform for rapid, low-cost point-of-care diagnostics for a variety of applications, particularly in resource-limited settings.
Biosensor with peptide recognition elements. (a) gold nanotransducer (b) nanotransducer with peptide biorecognition element (BRE) (c) nanotransducer with peptide BRE bound to Troponin I (cTnI) target molecule.
Stage of Research
The inventors have demonstrated that short peptide (aptamer) biorecognition elements on gold nanotransducers in a bioplasmonic paper device are more sensitive and specific for detecting troponin I than when larger antibodies are used as target capture agents.
- Point-of-care diagnostics – plasmonic biosensors for label-free, quantitative detection of biomarkers in body fluids using simple substrates and low-cost portable equipment
- demonstrated for troponin I detection, the most common clinical biomarker of myocardial infarction
- easily adapted to other biomarkers of interest by functionalizing the nanotranducers
- potential for multiplexed bioplasmonic paper device (BPD) to improve sensitivity or detect biomarkers for multiple conditions
- Shelf-stable detection molecules – aptamer peptides:
- have remarkable chemical, temporal and environmental stability
- retain target-recognition capability after exposure to elevated temperatures
- enable easy handling with no special storage conditions
- potential for simple, rapid and reliable diagnostic platform that can be deployed in even in low resource or austere settings such as an ambulance, battlefield or remote location
- analysis with a simple, low-cost, handheld vis-NIR spectrometer
- could hasten therapeutic intervention and save lives by eliminating the time needed for processing samples in a centralized laboratory
- enhanced LSPR response
- aptamer recognition has higher sensitivity and a lower detection limit than antibody-based detection
- small size of the aptamers minimizes exponential decay in refractive index sensitivity from the surface of the nanotransducers
- Tadepalli, S., Kuang, Z., Jiang, Q., Liu, K. K., Fisher, M. A., Morrissey, J. J., … & Singamaneni, S. (2015). Peptide functionalized gold nanorods for the sensitive detection of a cardiac biomarker using plasmonic paper devices. Scientific reports, 5, 16206.
- Bioplasmonic detection of biomarkers in body fluids using peptide recognition elements (U.S. Patent Application Publication No. US20180031483A1)