Characterization of dynamic solid phase DNA extraction from blood with magnetically controlled silica beads

Abstract

A novel solid phase extraction technique is described where DNA is bound and eluted from magnetic silica beads in a manner where efficiency is dependent on the magnetic manipulation of the beads and not on the flow of solution through a packed bed. The utility of this technique in the isolation of reasonably pure, PCR-amplifiable DNA from complex samples is shown by isolating DNA from whole human blood, and subsequently amplifying a fragment of the beta-globin gene. By effectively controlling the movement of the solid phase in the presence of a static sample, the issues associated with reproducibly packing a solid phase in a microchannel and maintaining consistent flow rates are eliminated. The technique described here is rapid, simple, and efficient, allowing for recovery of more than 60% of DNA from 0.6 microL of blood at a concentration which is suitable for PCR amplification. In addition, the technique presented here requires inexpensive, common laboratory equipment, making it easily adopted for both clinical point-of-care applications and on-site forensic sample analysis.

Microchip‐based forensic short tandem repeat genotyping

“…Due to the formation of the microsized pore structure, high surface‐to‐volume ratio is generated that can improve the DNA extraction efficiency. A microchamber can be fabricated by using a conventional photolithography on a glass or silicon substrate, by CNC milling, or laser ablation on the polymer substrate .…”

A magnetic bead-based DNA extraction and purification microfluidic device

“…Silica micropillars (Christel et al 1999;Cady et al 2003), silica beads (Tian et al 2000;Wolfe et al 2002), hybrid silica beads/sol-gel systems (Wolfe et al 2002;Breadmore et al 2003) and organic polymeric monoliths (Morishima et al 2002;Wen et al 2006Wen et al , 2007Klapperich 2006, 2008) are among various SPE systems that have been used to efficiently purify nucleic acids from various bio-fluids. Although there are few reports on the extraction and purification of nucleic acids from whole blood (Liu et al 2004;Yuen et al 2001;Duarte et al 2010), the majority of the reported microfluidic chips are designed to purify nucleic acids from homogeneous samples such as serum and cells lysate (Anderson et al 2000). However, practical applications in clinical analysis require processing of complex and heterogeneous samples such as whole blood and urine.…”

Microfluidic extraction and digital quantification of circulating cell-free DNA from serum

“…A variety of microfluidic devices has been developed for the solid-phase extraction of nucleic acids [13,14], but only few studies have focused on the purification of cellfree DNA from biological samples [15][16][17]. Microdevices employing silica chemistries (based on previous developments for standard spin column procedures) have been used for the isolation of DNA from prepurified samples or concentrated genomic DNA from blood samples (> 1 ng/μL), showing extraction efficiencies ranging from 45 to 70% [18][19][20][21]. However, silica-based technologies have been limited by the need of chaotropic salts for efficient DNA binding to the silica surface, and the use of several alcohol washing steps that can inhibit PCR reactions.…”