Bioinspired Sialic Acid Regulated Ion Nanochannel

Abstract

Human perception is inextricably linked to numerous ion channels, and sodium channel is one of the important ion channels. Sialic acid‐terminated glycan chains are commonly found on the surface of the sodium channel, which can induce the channel surface depolarization and thus contribute a regulation mechanism for the closing and opening (i.e., “ON” and “OFF”) of the sodium channel. However, the development of artificial ion channel to achieve precise regulation remains a challenging task. In this work, taking advantage of the conformational change of smart polymer from a contracted state to a swollen one, a functional polymer‐modified ion nanochannel is demonstrated that shows the free sialic acid‐responsive “ON” to “OFF” regulation in ion flow through the nanochannel. Furthermore, the distinct recognition interactions of the polymer toward different sialic acids allow for the nanochannel to exhibit the highly selective and sensitive recognition of them. This work provides a biomimetic perspective to understand the regulation of biological ion channel, but also presents the application scenarios in the analysis of sialic acids and sialylated glycans, as well as the capture of metastatic tumor cells.

Solid‐state Nanopores: Chemical Modifications, Interactions, and Functionalities

“…Besides the above coating methods, researchers have also invented some other promising coating methods, such as silanization treatment, [76] self‐assembled thiol monolayers, and [77–78] liquid lipid coatings [79–81] . electrostatic adsorption, [82] polymer modification after metal plating, [83] and electric‐field induced self‐assembly of polyelectrolytes, [84] atom transfer radical polymerization, [85–86] in situ polymerization, [87] and variety of grafting methods [88–91] . To demonstrate the practical impact of coating methods, Table 1 summarizes the characteristics of the main coating methods and the obtained nanopores.…”

“…[79][80][81] electrostatic adsorption, [82] polymer modification after metal plating, [83] and electric-field induced self-assembly of polyelectrolytes, [84] atom transfer radical polymerization, [85][86] in situ polymerization, [87] and variety of grafting methods. [88][89][90][91] To demonstrate the practical impact of coating methods, Table 1 summarizes the characteristics of the main coating methods and the obtained nanopores.…”

Recent Advances in the Modification and Characterization of Solid‐State Nanopores

“…The DNA modified nanopore could recognize cocaine molecules with good selectivity and excellent sensitivity. Similar approach was used by other groups [15,72] to decorate DNA, polymers, or peptides within the nanopores.…”

“…When the modified nanopore encounters the target molecules, two recognition events might happen; 1) Ions/molecules adsorb onto the polymer film and change the surface charge of the nanopore (Figure 1E); 2) Molecule adsorption triggers a conformational transition of the polymer chain from a “contracted” state to a “swollen” one, which further blocks the nanopore (Figure 1F). Either of the events will induce the decrease of the transmembrane current and the rectification ratio [15] (Figure 1G), by virtue of the extent of these variations, specific molecule recognition could be achieved.…”