Related Experiment Video
Updated: Sep 24, 2025
Author Spotlight: An Alternative Approach to Protein Quantification by Bradford Assay Using a Smartphone
Published on: September 8, 2023
Thread integrated smart-phone imaging facilitates early turning point colorimetric assay for microbes
Anusha Prabhu1, Giri Nandagopal M S2, Prakash Peralam Yegneswaran3,4
1Department of Biotechnology, Manipal Institute of Technology, Manipal Academy of Higher Education Manipal 576104 Karnataka India naresh.mani@manipal.edu maninaresh@gmail.com.
A novel, low-cost cotton thread assay combined with smartphone imaging rapidly detects pathogens like Candida albicans and Escherichia coli. This method significantly reduces microbial identification time, offering a scalable solution for resource-limited settings.
Area of Science:
- Microbiology
- Biosensing Technology
- Point-of-Care Diagnostics
Background:
- Conventional microbial identification methods are time-consuming (≈24 hours) and require specialized equipment and expertise.
- There is a need for rapid, low-cost, and accessible diagnostic tools, especially in resource-constrained environments.
- Colorimetric assays offer a visual detection method but often require subjective endpoint analysis.
Purpose of the Study:
- To develop a low-cost, thread-based microbial identification assay integrated with smartphone imaging.
- To achieve rapid and high-throughput detection of common pathogens, such as Candida albicans and Escherichia coli.
- To reduce the time and complexity associated with traditional microbial detection methods.
Main Methods:
- A multifilament cotton thread was functionalized with a test medium and pH indicator.
- Pathogen metabolic activity (sugar utilization and acid production) triggers a pH-dependent color change.
- Smartphone imaging was employed to capture and analyze the colorimetric changes for early detection of turning points.
Main Results:
- Visual detection of Candida albicans took ≈16 hours and Escherichia coli took ≈5 hours.
- Smartphone-based image analysis reduced detection times to ≈10 hours for Candida albicans and ≈1.5 hours for Escherichia coli.
- The method accurately identified the turning point of the colorimetric reaction, surpassing endpoint analysis.
Conclusions:
- The integrated thread-based assay and smartphone imaging provide a rapid, low-cost, and scalable microbial detection platform.
- This technology is suitable for resource-limited settings, minimizing the need for complex media preparation and instrumentation.
- The approach demonstrates high reproducibility and potential for broader application in biochemical assays.
