S.J. Reinholt, H.G. Craighead
Keywords: cancer, aptamer, microfluidics, genetic mutation
Summary:Genetic mutations in cancer cells are not only fundamental to the disease, but can also have tremendous impact on the efficacy of treatment. Identification of specific key mutations in a timely and cost-effective way would allow clinicians to better prescribe the most effective treatment options. Furthermore, cancer cells are constantly evolving, so regular testing of multiple important genes is also beneficial for monitoring disease progression and future treatment. Here, we present a novel microfluidic device to provide a platform for specifically capturing cancer cells and isolating the genomic DNA for specific amplification and sequence analysis. To filter out rare cancer cells from a complex mixture containing a diversity of cells, nucleic acid aptamers that specifically bind to cancer cells are immobilized within a microchannel containing pillars to increase the number of collisions with the surface and improve capture efficiency. The captured cells are then lysed and the genomic DNA is isolated via physical entanglement within a secondary micropillar array. This type of isolation enables multiple consecutive rounds of isothermal amplification to be performed to amplify different individual genes separately, since the genomic template is retained on the micropillars between subsequent amplifications. The amplified gene samples undergo Sanger sequencing, an inexpensive sequencing approach requiring a pure sample, to reveal the genetic sequence. The resulting sequence information is compared against the known wildtype gene, and any mutations are identified. This approach offers a way to monitor multiple genetic mutations in the same small population of cells, which is beneficial given the wide diversity in cancer cells, and requires very few cells to be extracted from the patient sample. With this capability for genetic monitoring, precision medicine should be more accessible for the treatment of cancer.