Hand-held tests developed from the work of the NUS BIGHEART team could help caregivers in remote areas diagnose disease quickly, accurately, and inexpensively
There is great demand in Asia for diagnostic tests that are cheap, accurate, and have a fast time to answer. Especially in Asia’s remote and mobile clinics where caregivers need immediate access to clinical laboratory test results at the time of patients’ visits.
Dark Daily has reported many times on new clinical laboratory tests that use smartphones in past e-briefings. They are among the most significant developments to impact the pathology industry in our times.
According to the NUS researchers, their test can screen, detect, and analyze multiple diseases through a nucleic acid test platform. Best of all, the test costs less than $1, operates at room temperature, and takes about 30 minutes to an hour to uncover diseases.
NUS published the study in Nature Communications.
Researchers Aim to Simplify Complex Lab Testing
“Rapid, visual detection of pathogen nucleic acids has broad applications in infection management,” the researchers wrote in their study. They found that a screening device using molecular agents to detect disease-specific molecules has implications for a range of diseases: from Zika and Ebola to hepatitis, dengue, malaria, and cancers, according to a news release.
The NUS researchers dubbed their creation enVision (enzyme-assisted nanocomplexes for visual identification of nucleic acids).
The enVision microfluidic system (above) consists of a series of enzyme–DNA nanostructures to enable target recognition, target-independent signaling, and visual detection. The common cartridge houses the universal signaling nanostructures, which are immobilized on embedded membranes, for target-independent signaling and visual detection. The platform is designed to complement the modular enVision workflow. (Image and caption copyright: National University of Singapore.)
“Conventional technologies—such as tests that rely on polymerase chain reaction to amplify and detect specific DNA molecules—require bulky and expensive equipment, as well as trained personnel to operate these machines. With enVision, we are essentially bringing the clinical laboratory to the patient,” said Nicholas Ho, PhD, an NUS Biomedical Institute for Global Health Research and Technology (BIGHEART) Research Fellow and study co-first author, in the news release.
NUS BIGHEART researchers include Assistant Professor Huilin Shao, PhD, at center holding the enVision cartridge, with Nicholas Ho, PhD, to the left and Lim Geok Soon, PhD, to the right. They tested the performance of enVision on human papillomavirus (HPV), a sexually transmitted infection and primary cause of cervical cancer. HPV has more than 100 subtypes of which 15 are malignant. The researchers studied samples from 35 NUS patients. (Photo copyright: National University of Singapore.)
“HPV is a global epidemic. While mostly benign, some of these infections can progress to cause deadly cervical cancer,” they wrote in Nature Communications. “Point-of-care testing that can distinguish the infection subtypes, and be performed at the patient level, could bring tremendous opportunities for patient stratification and accessible monitoring and is associated with better health outcomes.”
NUS researchers found that the enVision platform had a 95% accuracy rate in screening for HPV, as compared to conventional lab testing, according to Singapore’s Straits Times.
“While laboratory tests can detect one to two HPV strains, the kit is able to detect over 10 strains and has better coverage for each strain,” said Assistant Professor Huilin Shao, PhD, NUS BIGHEART, in the Straits Time article.
How Does it Work?
The test’s steps, according to an NUS News article, include:
- The tiny plastic chip holds the sample (blood, urine, or saliva) for analysis, along with a DNA “molecular machine” to recognize genetic sequences;
- This sample is channeled to a common signal cartridge containing another DNA molecular machine;
- Visual signals are evidence of disease-specific molecules and an assay turns from colorless to brown if disease is present;
- Further analysis, potentially using a smartphone app, could delve into the extent of an infection.
“The first machine is a recognition nanostructure which detects specific genetic sequences that relate to different kinds of diseases—the pathogens, bacteria, or viruses for example—and produces a signal,” Ho told NUS News. “It pairs up with what we call an amplifier nanostructure which takes that signal, amplifies it and turns it into a color read-out.”
The researchers note that more studies on other diseases are needed before marketing of the test kit, which they developed over 18 months. The NUS team also sees opportunities to enable better image capabilities and analysis algorithms through smartphone applications (apps).
“Large cohort studies on the detection of pathogen nucleic acids across a spectrum of diseases (e.g., other infections, cancers, inflammatory disorders) using various biological specimens (e.g., tissue, blood, urine) could be performed to validate the clinical utility of the enVision technology for diverse visual detection,” they concluded in Nature Communications.
As healthcare resources become limited and populations continue to grow, studies into portable, low-cost testing become more critical. Clinical laboratories performing tests in rural, outlying areas of the world will especially benefit from the work of researchers like the NUS BIGHEART team at University of Singapore.
—Donna Marie Pocius