Point-of-Care Nucleic Acid Detection of Infectious Disease

At a Glance

​Researchers at Colorado State University have developed a novel diagnostic assay to detect specific nucleic acids in patient samples. The assay integrates multiple different types of molecular assays (padlock-rolling circle amplification, nuclease protection, lateral flow immunoassay) to detect specific nucleic acids using isothermal amplification in a format that can be detected using a simple colorimetric readout.


Ultrasensitive sequence-specific detection of target nucleic acids has broad ranging applications in clinical diagnostics, water and food safety, environmental monitoring, biosafety and epidemiology. With the introduction of polymerase chain reaction (PCR) and other DNA amplification techniques such as recombinase polymerase amplification, template-mediate amplification, helicase-dependent amplification, loop-medicated isothermal amplification and rolling circle amplification, significant progress has been made in the field of molecular diagnostics and nucleic acid biosensors. However, PCR requires precise temperature control and cycling to perform DNA amplification, limiting its portability and application in point-of-care diagnostics.


This nucleic acid test involves several techniques to detect nucleic acids of various types. The padlock probe belongs to the class of capture by circularization techniques for performing capture of specific regions of nucleic acids. Probes used in this technique contain complementary sequences to the target sequences and probes are hybridized to capture the target, as seen in Figure 1, below. Also, the rolling circle amplification (RCA) is an isothermal nucleic acid amplification technique that describes a process of unidirectional nucleic acid replication and multiple copies of very small amount circular nucleic acid molecules can be obtained in a rapid manner.

The nuclease protection assay is used to identify individual RNA molecules in a sample. The nuclease protection probes are prepared by cloning part of the gene of interest in a vector under the control of different promoters. The promoters are recognized by the DNA dependent RNA polymerases.

With implementation of the lateral flow immunoassay, this device detects the presence of a target DNA or RNA in a sample. Each of these pads has the capacity to transport fluid (e.g., urine, blood, saliva, water) spontaneously. With this broad application of uses, this assay is poised for rapid adoption in multiple fields.


  • Detection of pathogenic nucleic acids in minimally processed tissue samples
  • Provides quick and accurate sample-to-answer results
  • Point-of-care diagnostic for infectious disease, including COVID-19
  • Portable, cost-effective, ultrasensitive


  • SNP genoptyping
  • Copy number detection
  • Tumor diagnosis
  • Pharmocogenomics
  • Food safety
  • Infectious disease detection
  • Environmental monitoring
Last Updated: October 2022
Pipetting samples in a laboratory setting

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