A team of researchers in the US has developed a handheld device that diagnoses genetic diseases at point-of-care.
Called CRISPR-Chip, the device combines a deactivated clustered regularly interspaced short palindromic repeats (CRISPR) Cas9 protein with electronic transistors to identify genetic mutations in DNA samples without the need for amplification or replication of the DNA segment using the polymerase chain reaction (PCR).
Avoiding the time-consuming PCR step is expected to enable the use of CRISPR-Chip for genetic testing in a doctor’s office or field work setting, rather than sending samples to a laboratory.
The method can also be used to assess the accuracy of gene-editing techniques.
The researchers included scientists from the University of California, Berkeley (UC Berkeley) and the Keck Graduate Institute (KGI) of The Claremont Colleges.
UC Berkeley bioengineering professor Niren Murthy said: “CRISPR-Chip has the benefit that it is really point-of-care. It is one of the few things where you could really do it at the bedside if you had a good DNA sample.
“Ultimately, you just need to take a person’s cells, extract the DNA and mix it with the CRISPR-Chip and you will be able to tell if a certain DNA sequence is there or not. That could potentially lead to a true bedside assay for DNA.”
The deactivated Cas9 protein in the chip is linked to the transistors, which are made from graphene. This complex detects the target DNA sequence, binds to it and induces a change in the graphene’s electrical conductance.
This leads to changes in the electrical characteristics of the transistor, which can be identified using the handheld device.
KGI assistant professor Kiana Aran said: “Graphene’s super sensitivity enabled us to detect the DNA-searching activities of CRISPR.
“CRISPR brought the selectivity, graphene transistors brought the sensitivity and, together, we were able to do this PCR-free or amplification-free detection.”
The researchers tested the device’s sensitivity by using it to identify common genetic mutations in DNA samples from Duchenne muscular dystrophy patients.
The team is currently planning to refine CRISPR-Chip to simultaneously detect various genetic mutations. They also hope that the handheld device can help in personalised treatments for patients.