A multidisciplinary team at NUS BIGHEART has developed enVision — a portable, easy-to-use, and inexpensive device for quick and accurate screening of diseases. (Credit: NUS)

A portable, easy-to-use device provides quick and accurate screening of diseases. The versatile technology platform called enVision (enzyme-assisted nanocomplexes for visual identification of nucleic acids) can be designed to detect a wide range of diseases.

The platform can test everything from emerging infectious diseases (e.g., Zika and Ebola) and high-prevalence infections (e.g., hepatitis, dengue, and malaria) to various types of cancers and genetic diseases.

The test takes between 30 minutes to one hour to detect the presence of diseases, which is two to four times faster than existing infection diagnostics methods. In addition, each test kit costs under S$1 – 100 times lower than the current cost of conducting similar tests.

The research team used the human papillomavirus (HPV), the key cause of cervical cancer, as a clinical model to validate the performance of enVision. In comparison to clinical gold standard, this novel technology has demonstrated superior sensitivity and specificity.

In addition, test results are easily visible – the assay turns from colorless to brown if a disease is present —- and could also be further analyzed using a smartphone for quantitative assessment of the amount of pathogen present. This makes the test ideal for personal healthcare and telemedicine.

In this study, the team developed patented DNA molecular machines that can recognize genetic material of different diseases and perform different functions. The novel platform adopts a plug-and-play modular design and uses microfluidic technology to reduce the number of samples and biochemical reagents required as well as to optimize the technology’s sensitivity for visual readouts.

The platform has three key steps — target recognition, target-independent signal enhancement, and visual detection. It employs a unique set of molecular switches, composed of enzyme-DNA nanostructures, to accurately detect, as well as convert and amplify molecular information into visible signals for disease diagnosis.

Each test is housed in a tiny plastic chip that is preloaded with a DNA molecular machine that is designed to recognize disease-specific molecules. The chip is then placed in a common signal cartridge that contains another DNA molecular machine responsible for producing visual signals when disease-specific molecules are detected.

Multiple units of the same test chip — to test different patient samples for the same disease — or a collection of test chips to detect different diseases could be mounted onto the common cartridge.