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Updated: Jul 2, 2025
Design and Development of Aptamer–Gold Nanoparticle Based Colorimetric Assays for In-the-field Applications
Published on: June 23, 2016
Instant Candida albicans Detection Using Ultra-Stable Aptamer Conjugated Gold Nanoparticles
Kimberley Clack1, Mohamed Sallam1,2,3, Serge Muyldermans4
1Queensland Micro and Nanotechnology Centre (QMNC), Nathan Campus, Griffith University, Nathan, QLD 4111, Australia.
Abstract:
Fungal pathogens such as Candida albicans have significant impacts on women's health and the economy worldwide. Current detection methods often require access to laboratory facilities that are costly, inconvenient, and slow to access. This often leads to self-diagnosis, self-treatment and eventual antifungal resistance. We have created a rapid (within five minutes), cost-effective, and user-friendly method for the early detection of Candida albicans. Our platform utilises aptamer-tagged-gold-core-shell nanoparticles for Candida albicans detection based on the presence of 1,3-β-d glucan molecules. Nanoparticle aggregation occurs in the presence of Candida albicans fungal cells, causing a redshift in the UV-visible absorbance, turning from pink/purple to blue. This colour change is perceptible by the naked eye and provides a "yes"/"no" result. Our platform was also capable of detecting Candida albicans from individual yeast colonies without prior sample processing, dilution or purification. Candida albicans yeast cells were detected with our platform at concentrations as low as 5 × 105 cells within a 50 μL sample volume. We believe that this technology has the potential to revolutionise women's health, enabling women to test for Candida albicans accurately and reliably from home. This approach would be advantageous within remote or developing areas.
Insights
A new aptamer-based nanoparticle platform enables rapid, cost-effective, and user-friendly detection of Candida albicans, a common fungal pathogen impacting women's health.
Area of Science:
- Biomedical Engineering
- Nanotechnology
- Infectious Disease Diagnostics
Background:
- Fungal infections, particularly Candida albicans, pose significant global health and economic challenges.
- Current diagnostic methods for Candida albicans are often laboratory-dependent, leading to delays, high costs, and potential antifungal resistance due to delayed treatment.
- There is a critical need for accessible, rapid, and accurate diagnostic tools for early detection.
Purpose of the Study:
- To develop a novel, rapid, cost-effective, and user-friendly diagnostic platform for the early detection of Candida albicans.
- To utilize aptamer-functionalized gold core-shell nanoparticles for sensitive and specific pathogen identification.
- To provide a point-of-care diagnostic solution for Candida albicans.
Main Methods:
- Development of aptamer-tagged gold core-shell nanoparticles targeting 1,3-β-d glucan molecules.
- Utilizing nanoparticle aggregation-induced colorimetric changes (redshift in UV-visible absorbance) for visual detection.
- Assessing detection limits and performance on individual yeast colonies without sample pre-processing.
Main Results:
- A rapid (5-minute) colorimetric assay for Candida albicans detection was successfully developed.
- The platform demonstrated a visual color change from pink/purple to blue upon nanoparticle aggregation.
- Detection of Candida albicans was achieved at concentrations as low as 5 × 10^5 cells/50 μL, even from unprocessed colonies.
Conclusions:
- The aptamer-nanoparticle platform offers a promising solution for the early, accessible detection of Candida albicans.
- This technology has the potential to significantly improve women's health outcomes, particularly in resource-limited settings.
- The user-friendly, visual readout facilitates point-of-care diagnostics and empowers individuals with reliable self-testing capabilities.
