Investigating the translocation of λ-DNA molecules through PDMS nanopores

Abstract

We investigate the translocation of λ-DNA molecules through resistive-pulse PDMS nanopore sensors. Single molecules of λ-DNA were detected as a transient current increase due to the effect of DNA charge on ionic current through the pore. DNA translocation was found to deviate from a Poisson process when the interval between translocations was comparable to the duration of translocation events, suggesting that translocation was impeded during the presence of another translocating molecule in the nanopore. Characterization of translocation at different voltage bias revealed that a critical voltage bias was necessary to drive DNA molecules through the nanopore. Above this critical voltage, frequency of translocation events was directly proportional to DNA concentration and voltage bias, suggesting that transport of DNA from the solution to the nanopore was the rate limiting step. These observations are consistent with experimental results on transport of DNA through nanopores and nanoslits, and the theory of hydrodynamically driven polymer flow in pores.

Nanopore detection of double stranded DNA using a track-etched polycarbonate membrane

“…Kasianowicz and co-workers showed the effect of electrical field on the translocation of DNA and RNA molecules and discussed the positive its contribution to overcome the entropic barrier [8,50]. Chen and Sen confirmed the same observation using artificial nanopore sensors [26,45]. In addition to the The same phenomena also showed in addition to experimental studies, the entropic barrier also discussed theoretically based on different parameters such as effect of solvent, nanopore size and adsorption [51][52][53].…”

“…So the researches for synthetic nanopores that could meet these qualifications were in demand. Alternative techniques such as e-beam lithography [18,19], nanopipettes [20,21], ion-beam sculpting [22][23][24], micromolding [25,26], laser melting [27,28] and track-etch method [29][30][31][32] have been developed to fabricate and engineer synthetic nanopores to overcome the limitations of biological nanopores. The ability to control the pore size very precisely, to change the surface characteristics and to integrate with electronics or optical systems made the synthetic nanopores advantageous over the biological ones [33].…”

Voltage-Driven Translocation of DNA through a High Throughput Conical Solid-State Nanopore

“…So, in order to reduce these negative impacts, several or more nanopores with approximate size are needed to achieve enough amount of data. Alternatively, with the advantages of weak DNA–pore interaction and longtime stability, larger nanopores in size of tens to hundreds nanometers are considered for the current DNA analysis with specific characteristics and sensing abilities,[36]–[38] which can ensure free passage of the molecules, suppress the conformational changes of long DNA inside pores and effectively provide a high resolution. However, the signal-to-noise ratio of the blockade current will conspicuously deteriorate if the pore is too large compared to the size of molecules.…”

Enhanced discrimination of DNA molecules in nanofluidic channels through multiple measurements

“…The transient current increase is due to the introduction of mobile counter-ions screening the inherent charge on the DNA molecules into the nanochannel 7, 8 . For Δ n counterions of mobility μ introduced into a channel of length L , with fraction b of counterions that are mobile, electron charge e , and voltage bias V , the change in ionic current is approximately given by 24 …”