Analyzes: fast and cheap
A multidisciplinary team of researchers from the National University of Singapore, led by Associate Professor Shao Huilin, has developed a portable, inexpensive and easy-to-use device for fast and accurate disease screening. The enVision universal microfluidic technology platform (e nzyme-assisted n anocomplexes for vis ual i dentification o f n ucleic acids, enzyme-associated nanocomplexes for visual identification of nucleic acids) can be adapted to detect a wide range of diseases: from the recently buzzed Zika and Ebola viruses and widespread infections (hepatitis, tropical fever and malaria) to various types of cancer, as well as hereditary diseases.
The enVision platform allows you to diagnose the disease within 30-60 minutes, which is 2-4 times faster than modern methods of diagnosing infectious diseases. In addition, the cost of any diagnostic kit based on this platform does not exceed $ 1, which in some cases is 100 times less than the cost of conducting similar tests.
The platform is based on molecular mechanisms developed by the authors that allow recognizing the genetic material of pathogens of various diseases. A unique complex of molecular switches based on nanostructured complexes of enzymes and DNA ensures the performance of three stages of the device: target recognition, target-independent signal amplification (aplication of molecular information into visible signals) and visual signal registration.
Each test is placed inside a plastic chip and contains DNA-based molecular mechanisms designed to recognize disease-specific molecules. This chip is placed inside a common signal cartridge, which functions due to another molecular mechanism that provides the formation of visual signals when detecting such molecules. Up to four chips with samples of different patients undergoing examination for the same disease can be loaded into such a cartridge.
The modular design and microfluidic technology make it possible to minimize the amount of analyzed biological material and reagents, as well as optimize the sensitivity of the technology to obtain visual results.
The color indicator obtained during the analysis varies from colorless to dark brown in the presence of a disease, and its further analysis using a smartphone application allows a quantitative assessment of the pathogenic load.
In addition, the enVision platform provides exceptional sensitivity, accuracy, speed, ease of use and low cost. It functions at room temperature and does not require thermostats, pumps and other auxiliary equipment, which makes it suitable for conducting tests at the patient's bedside, in a polyclinic, as well as for telemedicine, which is gaining popularity.
As a clinical model for validating the effectiveness of the enVision platform, the authors used the human papillomavirus, which is the main cause of cervical cancer. As a result, its sensitivity and specificity exceeded the sensitivity and specificity of the polymerase chain reaction (PCR) method, which is considered the clinical "gold standard". enVision made it possible not only to determine different strains of the virus with high accuracy, but also to identify differences within the same strain.
It took Dr. Huilin and her team about a year and a half to develop the enVision platform. They are currently developing a sample preparation module – DNA isolation and processing – for subsequent integration into the platform. In addition, the researchers hope that in the future, the efficiency of the platform they created will increase even more by improving the algorithms for analyzing and correcting images in the smartphone software being developed for it.
Article by Nicholas R.Y. Ho et al. Visual and modular detection of pathogen nucleic acids with enzyme–DNA molecular complexes is published in the journal Nature Communications.
Evgenia Ryabtseva, portal "Eternal Youth" http://vechnayamolodost.ru based on the materials of the National University of Singapore: New test kit invented by NUS researchers enables quick, accurate, and inexpensive screening of diseases.