ODOSA - One-Drop, One-Step Assay for Circulating Tumor Cell Detection



The invention is a cell-specific, intracellularly-activated, one step assay for the detection of circulating tumor cells (CTC) in a single drop of blood. The invention is based on cell-specific aptamers linked to fluorophores and quenchers. Lysosomal degradation leads to release of quenching and switches on a strong fluorescent signal in CTC’s.



When a tumor metastasizes, it sheds cells into the blood stream and these tumor cells are known as CTCs. The presence of CTCs is a strong predictor of prognosis and can also be used to monitor the effectiveness of treatment. Currently there is only one FDA approved platform for detecting CTCs in patient blood samples – the CELLSEARCH┬« CTC platform from Veridex, Llc. This system requires the use of 7.5 mL of blood and consists of a time-consuming, multi-step, only semi-automated process. A new assay in development, the CytoTrack assay from CytoTrack ApS, is also a multi-step assay that is not amenable to high-throughput screening and uses large sample volumes.



ODOSA’s advantages over current assays are:

  • Highly sensitive - can detect a single CTC in one drop of blood.
  • Highly specific - uses aptamers to target specific tumor cell ligands. Aptamers are more specific than antibodies.
  • Multiplex capability – Can detect multiple different tumor biomarkers in a single well.
  • Rapid - one step assay since no sample preparation or washing is required.
  • Cheap - the aptamer is synthetic and so cheaper to produce than antibodies and simpler to modify.
  • No background - the probe is not fluorescent until activated inside the specific tumor cell.
  • Uses less patient sample, just a drop of blood.
  • Can use RNA aptamers or more stable single stranded DNA aptamers.
  • Uses an optical detection system and can easily be used in a high throughput screening platform.



Patent Application

United States provisional patent application filed.




Patent Information:
Licensing Contact
Belisa Diaz