Direct Plasmonic Detection of Circulating RAS Mutated DNA in Colorectal Cancer Patients

By exploiting a liquid biopsy approach, we developed an ultrasensitive nanoparticle-enhanced plasmonic method for detecting RAS single nucleotide variants (SNVs) in the plasma of CRC patients. The PCR-free method we developed is based on an imaging platform and allows the direct detection of ~1 attomolar RAS sequences in plasma with a sandwich hybridization assay using peptide nucleic acids probes. The assay involves a simple pre-analytical procedure that does not require the extraction of tumor DNA from plasma and detects it in volumes as low as 40 uL of plasma, which is at least an order of magnitude smaller than that required by state of the art liquid biopsy technologies. The most prevalent RAS SNVs are detected in DNA from tumor tissue with 100% sensitivity and 83.33% specificity. Spike-in experiments in human plasma further encouraged assay application on clinical specimens. Assay performances were then proven in plasma from CRC patients and healthy donors, demonstrating its promising avenue for cancer monitoring.<br>

Direct Plasmonic Detection of Circulating RAS Mutated DNA in Colorectal Cancer Patients

By exploiting a liquid biopsy approach, we developed an ultrasensitive nanoparticle-enhanced plasmonic method for detecting RAS single nucleotide variants (SNVs) in the plasma of CRC patients. The PCR-free method we developed is based on an imaging platform and allows the direct detection of ~1 attomolar RAS sequences in plasma with a sandwich hybridization assay using peptide nucleic acids probes. The assay involves a simple pre-analytical procedure that does not require the extraction of tumor DNA from plasma and detects it in volumes as low as 40 uL of plasma, which is at least an order of magnitude smaller than that required by state of the art liquid biopsy technologies. The most prevalent RAS SNVs are detected in DNA from tumor tissue with 100% sensitivity and 83.33% specificity. Spike-in experiments in human plasma further encouraged assay application on clinical specimens. Assay performances were then proven in plasma from CRC patients and healthy donors, demonstrating its promising avenue for cancer monitoring.<br>

Development of a sandwich hybridization assay for the identification and quantification of red drum (Sciaenops ocellatus) eggs: a novel tool for fishery research and management

Egg identification and quantification are crucial to understanding the spawning and recruitment dynamics of economically important fish species. This study describes the development of a novel molecular method for finfish egg identification that eliminates the need for time-consuming microscopy. Sandwich hybridization assay (SHA) uses two ribosomal RNA (rRNA)-targeted oligonucleotides to directly detect unpurified and unamplified rRNA. Probes were designed to complement the internal transcribed spacer (ITS) region of the red drum (Sciaenops ocellatus), an important recreational game fish for which spawning and reproductive information is sparse. Sample homogenization procedures were modified to disrupt egg chorion, and the resultant assay detected S. ocellatus eggs and tissues without cross-reactivity. Standard curves were linear (y450 = 0.001x + 0.054; R2 = 0.999), showing potential for quantitative uses, and the lower limit of detection was 5 eggs·mL−1 homogenate. Ontogenetic stage had a significant effect (ANOVA, p < 0.05) on optical density. The assay successfully detected S.ocellatus eggs in field samples from Charleston Harbor, South Carolina, and could be incorporated into current management practices or adapted to other species.