Viruses are conventionally detected by RT-PCR. This method requires long analysis time, highly trained professionals, and often shows non-specific characteristics. Antigens and antibodies (Ag/Ab) are commonly used for fluorescence immunoassay. However, the fluorescent signal from the individual fluorescent molecule attached to the antibody is extremely weak and requires signal amplification.


This invention provides a way for a quicker and more efficient method of DNA and virus detection by rolling circle amplification. The integration of the multi-padlock-based RCA approach with Ag/Ab immune-RCA has many advantages over the conventional Ag/Ab immunoassay.


Technology Overview

RCA colorimetric detection is applied from the DNA fragment attached to the antibody, sensitively capturing the target viruses, such as SARS-CoV-2. The antibody used is specifically sensitive to the target virus. The antibody-attached DNA is used for the template for amplification. The circular DNA is comprised of a target binding complementary sequence to the target viral DNA colorimetric DNA sequence to be amplified for the later RCA reaction. It gets hybridized with the DNA-attached to the antibody capturing the target virus. The colorimetric readout from the amplified DNA having a special structure “G-quadruplex DNAzyme (GQ-DNA)”. This GQ-DNA product gets transformed in the amplified DNA fragment to be a visible readout of the color signal by hydrolysis of color substrate.



  • Fully automated system
  • Rapid detection method
  • Reduced consumption of analytical reagents including molecular detection probes
  • Single virus copy number level of detection is expected
  • Lightweight, portable device
  • Cost-efficient
  • Technical knowledge or training is not required to perform the test



  • Point of care testing
  • Rapid and accurate testing of COVID-19
  • Analysis of DNA and RNA fragments, proteins, exosomes, etc.



  • License
  • Partnering
  • Research collaboration


Patent Information:
For Information, Contact:
Vaibhav Saini
Senior Manager Commercialization
Northeastern University
Ji Won Lim
Tania Konry
Analytical Chemistry