A multidisciplinary team of researchers has developed a portable, easy-to-use device for quick and accurate screening of diseases. This versatile technology platform called enVision (enzyme-assisted nanocomplexes for visual identification of nucleic acids) can be designed to detect a wide range of diseases – from emerging infectious diseases and high-prevalence infections to various types of cancers and genetic diseases.

enVision 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 enVision platform is extremely sensitive, accurate, fast, and low-cost. It works at room temperature and does not require heaters or special pumps, making it very portable. With this invention, tests can be done at the point-of-care, for instance in community clinics or hospital wards, so that disease monitoring or treatment can be administered in a timely manner to achieve better health outcomes," said team leader Assistant Professor Shao Huilin.

Superior sensitivity and specificity compared to clinical gold standard

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.

"enVision is not only able to accurately detect different subtypes of the same disease, it is also able to spot differences within a specific subtype of a given disease to identify previously undetectable infections," Asst Prof Shao added.

Bringing the lab to the patient

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 enVision an ideal solution for personal healthcare and telemedicine.

With enVision, we are essentially bringing the clinical laboratory to the patient. Minimal training is needed to administer the, test and interpret the results, so more patients can have access to effective, lab-quality diagnostics that will substantially improve the quality of care and treatment," said Dr Nicholas Ho.

Versatile point-of-care diagnostic device

In this study, Asst Prof Shao and her team developed patented DNA molecular machines that can recognize genetic material of different diseases and perform different functions. These molecular machines form the backbone of the enVision platform.

"The enVision 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," explained Dr Lim Geok Soon. 

Future work

Asst Prof Shao and her team took about a year and a half to develop the enVision platform. Building on the current work, the research team is developing a sample preparation module – for extraction and treatment of DNA material – to be integrated with the enVisionplatform to enhance the point-of-care application.

In addition, the research team foresees that the smartphone app could include more advanced image correction and analysis algorithms to further improve its performance for the real-world application. This research work was published in prestigious scientific journal Nature Communications.