On-chip DNA preconcentration in different media conductivities by electrodeless dielectrophoresis

Abstract

Electrodeless dielectrophoresis is the best choice to achieve preconcentration of nanoparticles and biomolecules due to its simple, robust, and easy implementation. We designed a simple chip with microchannels and nano-slits in between and then studied the trapping of DNA in high conductive medium and low conductive medium, corresponding to positive and negative dielectrophoresis (DEP), respectively. It is very important to investigate the trapping in media with different conductivities since one always has to deal with the sample solutions with different conductivities. The trapping process was analyzed by the fluorescent intensity changes. The results showed that DNA could be trapped at the nano-slit in both high and low conductive media in a lower electric field strength (10 V/cm) compared to the existing methods. This is a significant improvement to suppress the Joule heating effect in DEP related experiments. Our work may give insight to researchers for DNA trapping by a simple and low cost device in the Lab-on-a-Chip system. V C 2015 AIP Publishing LLC. [http://dx

DNA dielectrophoresis: Theory and applications a review

“…Moreover, Li et al. determined that the type of dielectrophoresis, that is, negative or positive dielectrophoresis, depends on the buffer conductivity , which is in good agreement to the theory (see Section ).…”

“…In 2015, Li et al. investigated DNA trapping behavior in nanoslits for different medium conductivities . They observed that the electrokinetic effects of electrophoresis, electroosmotic flow, and dielectrophoresis were affected by the buffer conductivity, similar to Regtmeier et al.…”

“…Continuous flow concentration according to our definition was not found for DNA dielectrophoresis. However, several groups presented DNA concentration at fixed locations, for example, .…”

“…The majority of the devices for trapping DNA with iDEP consist of posts or constrictions in microfluidic devices . Another way for generating an inhomogeneous electric field is by using a nanopipette.…”

Preconcentration of diluted mixed-species samples following separation and collection in a micro–nanofluidic device

“…Consequently, the realization of microfluidic platforms for the manipulation and analysis of biological and chemical samples has attracted significant interest in recent decades. [1][2][3][4] Human blood samples include many proteins with relevance to disease diagnosis and therapeutic monitoring. However, biochemical samples such as blood typically comprise many different components, including deoxyribonucleic acid (DNA), proteins, cells, and even ions.…”