Microscopic Screening of Cyclodextrin Channel Blockers by DiffusiOptoPhysiology

Abstract

Blockers of pore-forming toxins (PFTs) limit bacterial virulence by blocking relevant channel proteins. However, screening of desired blockers from a large pool of candidate molecules is not a trivial task. Acknowledging its advantages of low cost, high throughput, and multiplicity, DiffusiOptoPhysiology (DOP), an emerging nanopore technique that visually monitors the states of individual channel proteins without using any electrodes, has shown its potential use in the screening of channel blockers. By taking different α-hemolysin (α-HL) mutants as model PFTs and different cyclodextrins as model blockers, we report direct screening of pore blockers solely by using fluorescence microscopy. Different combinations of pores and blockers were simultaneously evaluated on the same DOP chip and a single-molecule resolution is directly achieved. The entire chip is composed of low-cost and biocompatible materials, which is fully disposable after each use. Though only demonstrated with cyclodextrin derivatives and α-HL mutants, this proof of concept has also suggested its generality to investigate other pore-forming proteins.

Multicharged cyclodextrin supramolecular assemblies

“…Li and co-workers reported a light-driven linear helical supramolecular polymer based on a bipyridinium-and Azomodified chiral 1,1 0 -binaphthyl monomer (M), bis(p-sulfonatocalix [4]arene) (bis-SC4A), and a-CD (Fig. 45).…”

“…When 2 equiv. of WP5 was added to the g-CD * TPEA solution to form pseudo [4]rotaxane, dual chiral induction from g-CD to TPEA (negative ICD 1 ) and continuous dynamic racemic WP5 (positive ICD 2 ) was observed. Therefore, stoichiometric changes of WP5 were an effective strategy for inducing topological transitions from the vesicular form to pseudo [4]rotaxane, triggering chiral induction of both g-CD and WP5.…”

“…For example, Ke and co-workers reported tunable solid-state fluorescent materials for supramolecular encryption based on g-CD, cucurbit [8]uril (CB [6]), the diazaperopyrenium (DAPP) dication, and two pyrene stoppers. 381 Hetero [4]rotaxane R4Á 4Cl was synthesized by a cooperative capture strategy, in which g-CD encircled the DAPP unit (Fig. 49a).…”

“…The use of rotaxanes for molecular recognition through their 3D topological binding sites has recently been developed. Yang and co-workers reported g-CD-CB [6]-cowheeled hetero [4]rotaxanes with RTP emission for the specific sensing of tryptophan. 382 The hetero [4]rotaxanes were synthesized via CB [6]-templated azide-alkyne 1,3-dipolar cycloaddition from aqueous solutions of the guest and g-CD, using selected naphthalene or biphenyl derivatives as the rotaxane axis (Fig.…”

“…Cyclodextrins (CDs), the well-known family of supramolecular macrocyclic host molecules, have been widely applied in analytical chemistry, [1][2][3][4][5] catalysis, [6][7][8][9][10] materials science, [11][12][13][14] biological science, [15][16][17][18][19] and other fields. [20][21][22][23] Recently, these macrocyclic systems have also emerged as promising building blocks for functional nanomaterials based on the host-guest chemistry of CDs.…”