Size‐dependent dextran loading in protein nanotube with an interior wall of concanavalin A

Abstract

This paper describes the synthesis and structure of protein nanotube (NT) with a lectin interior surface and its size‐dependent dextran loading ability in aqueous medium. The NTs were prepared using an alternating layer‐by‐layer build‐up assembly of poly‐l‐arginine (PLA) and human serum albumin (HSA) in a track‐etched polycarbonate (PC) membrane (pore diameter, 400 nm), subsequently coating concanavalin A (ConA) as the last layer. Dissolution of the PC template yielded (PLA/HSA)2PLA/ConA NTs with 419 ± 14 nm outer diameter and 50 ± 7 nm wall thickness. In a 2‐[4‐(2‐hydroxyethyl)‐1‐piperazinyl]ethanesulfonic acid (HEPES) buffered solution, the NTs captured fluorescein isothiocyanate (FITC)‐labeled dextran [molecular weight 4 kDa, FITC‐Dex(4k)] efficiently into the pores. The ratio of the bound FITC‐Dex(4kDa)/ConA was estimated to be 2.1 (mol/mol). Two of four glucosyl‐residue binding sites of ConA on the wall presumably faced to the aqueous inner phase of the tube, and they can bind FITC‐Dex(4k). On the one hand, only half amount of FITC‐Dex was loaded into the channels when the molecular weight of the dextran is greater than 20 kDa. Small‐angle X‐ray scattering measurements revealed that the radius of gyration (Rg) of the FITC‐Dex(4k) is 1.45 nm (5.0 mg/ml), which is satisfactorily small to interact with the each binding site of ConA independently. In contrast, the Rg values of FITC‐Dex(20k) and FITC‐Dex(40k) were 3.75 nm (5.0 mg/ml) and 6.62 nm (4.0 mg/ml), respectively. These large dextrans probably formed an equivalent complex with ConA on the tube wall. Copyright © 2014 John Wiley & Sons, Ltd.

The Characterisation and Quantification of Immobilised Concanavalin A on Quartz Surfaces Based on The Competitive Binding to Glucose and Fluorescent Labelled Dextran

“…The smaller Alexa 488 dextran (M W = 3 kDa) has a hydrodynamic diameter below that of Con A, which would facilitate binding to only one active Con A molecule, and with a lower tendency of obstructing the binding site of the neighbouring monomer/molecule. A similar observation was made in the paper by Shiraishi et al [46].…”

Biospecific Self‐Assembly of a Nanoparticle Coating for Targeted and Stimuli‐Responsive Drug Delivery

“…Con A is known to bind a variety of sugars and glycoproteins and thus provides a means to self‐assemble various functionalities to the Con A–glycogen coating. In this study, we examined the incorporation of transferrin glycoproteins into the coating as a means to confer targeting and cellular uptake functionality .…”

The Endothelial Glycocalyx Controls Interactions of Quantum Dots with the Endothelium and Their Translocation across the Blood–Tissue Border

“…Dextran molecules with a weight of 4 kDa (gyration radius (R g ) ∼ 1.4 nm) were able to penetrate the eGCX within a minute; 50 kDa dextran (R g ∼ 5.8 nm) only slowly infiltrated the eGCX in the time course of 30 min, and 150 kDa dextran (R g ∼ 11.2 nm) did not penetrate the intact eGCX at all. 30,42,43 The QDs employed in this study have a hydrodynamic diameter of 41.9 ± 0.3 nm after incubation in serum (18.1 ± 0.218 nm in PBS) and, therefore, are larger than the 150 kDa dextran which has been shown not to penetrate the healthy eGCX. 24 Interestingly, Gromnicova and colleagues have shown in vitro that the enzymatic digestion of the eGCX does not increase the uptake of gold NPs, which are smaller than 5 nm as assessed by transmission electron microscopy, correspondingly pointing to a size-dependent role of the eGCX barrier function.…”