Field-Driven Translocation of Regular Block Copolymers through a Selective Liquid−Liquid Interface

Abstract

We propose a simple scaling theory describing the variation of the mean first passage time (MFPT) τ (N, M ) of a regular block copolymer of chain length N and block size M which is dragged through a selective liquid-liquid interface by an external field B. The theory predicts a non-Arrhenian τ vs. B relationship which depends strongly on the size of the blocks, M , and rather weakly on the total polymer length, N . The overall behavior is strongly influenced by the degree of selectivity between the two solvents χ.The variation of τ (N, M ) with N and M in the regimes of weak and strong selectivity of the interface is also studied by means of computer simulations using a dynamic Monte Carlo coarse-grained model. Good qualitative agreement with theoretical predictions is found. The MFPT distribution is found to be well described by a Γ -distribution. Transition dynamics of ring-and telechelic polymers is also examined and compared to that of the linear chains.The strong sensitivity of the "capture" time τ (N, M ) with respect to block length M suggests a possible application as a new type of chromatography designed to separate and purify complex mixtures with different block sizes of the individual macromolecules.

Heteropolymer translocation through nanopores

“…[38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55] For a polymer threading through a nanopore, loss of available configurations due to the geometric constriction leads to an effective entropic barrier. Kasianowicz et al 7 demonstrated that an electric field can drive single-stranded DNA and RNA molecules through the water-filled ␣-hemolysin channel and that the passage of each molecule is signaled by a blockade in the channel current.…”

“…23,26,28,31 This has been indicated to be inappropriate for the study of translocation dynamics. [38][39][40][41][42][43][44] Most recently, we have investigated both free and forced translocation using both the two-dimensional fluctuating bond model with single-segment Monte Carlo moves 42,43 and Langevin dynamic simulations. 44,45 For the free translocation, 42,44 we numerically verified that the translocation time ϳ N 1+2 , where N is the chain length and is the Flory exponent.…”

“…[1][2][3] Due to various potential technological applications, such as rapid DNA sequencing, [4][5] gene therapy, and controlled drug delivery, 6 the polymer translocation has become a subject of intensive experimental, [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] theoretical , and numerical studies. [38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55] For a polymer threading through a nanopore, loss of available configurations due to the geometric constriction leads to an effective entropic barrier. Kasianowicz et al 7 demonstrated that an electric field can drive single-stranded DNA and RNA molecules through the water-filled α-hemolysin channel and that the passage of each molecule is signaled by a blockade in the channel current.…”

Mean velocity and effective diffusion constant for translocation of biopolymer chains across membrane

“…(16) and b 0 is given in Eq. (19). Therefore, constant A is determined by all of the constant transition rates.…”

“…Explicit expressions for a k s and a k s can also be obtained via Eqs. (15,18,19,23,25). Next, we begin to derive the expressions for T k s and T k s. In the stationary-state limit (see Eqs.…”