B-185 A Comparison Between Two Oral Sample Collection Devices on Preserving High-Quality Genomic DNA

Abstract

Abstract Background High-quality genomic testing significantly enhances the knowledge on gene-disease association, and greatly benefits future biomedical research and precision medicine. However, widely used saliva sample collection presents challenges with high-quality and quantity of human DNA and high bacterial DNA ratio. In this study, we validated the performance of two commercially available oral collection devices for their ability to preserve high-quality genomic DNA long-term at room temperature. Methods Fifty-one buccal samples in total from twelve donors were collected using two kinds of commercially available oral sample collection devices (iSWAB®-DNA (Device 1) and OCD-100 (Device 2)). All of the collected samples were stored at ambient temperature for up to 1 year. Collected samples were extracted with QIAamp Blood Mini Kit (Qiagen) at baseline, 30 days, 60 days, and 1 year. All DNA yields were measured using a Nanodrop One Microvolume UV-Vis Spectrophotometer; TapeStation System was used for determining the integrity of DNA. The bacterial DNA ratio was estimated by quantitative PCR with primers targeting the 16S rRNA gene known to be present in prokaryotes but not eukaryotes. Results Device 1 had higher yield (Device 1: 18.59 ± 8.98; Device 2: 6.44 ± 4.62), lower bacterial DNA ratio (Device 1: 2.06 ± 1.93; Device 2: 3.79 ± 4.58), and higher overall DNA integrity (Device 1: 6.1 ± 0.31; Device 2: 5.42 ± 0.96) compared to Device 2. Device 1 demonstrated longer post-collection sample stability at ambient temperature compared with Device 2 regarding DNA yield, bacterial DNA ratio and DNA integrity. No significant changes in DNA yield, integrity, and bacterial DNA ratio were observed after one year of storage in Device 1. No significant changes in DNA yield, integrity, and bacterial DNA ratio were observed after 60 days of storage in Device 2. However, Device 2 showed a significant increase in DNA yield, bacterial DNA ratio, and DNA integrity comparing baseline to 1 year. Conclusions Device 1 preserves higher quantity and quality of DNA from oral samples at ambient temperature for up to 1 year. These advantages significantly enhance efficiency and cost-effectiveness in downstream applications such as genotyping and sequencing, making it a valuable tool in genomics research with a commendable success rate.