Issue 36, 2019, Issue in Progress

Electrospinning of pyrazole-isothiazole derivatives: nanofibers from small molecules

Abstract

We investigate the electrospinning of small molecules, specifically designed peptide derivatives of the pyrazole-isothiazole scaffold. Such non-natural peptides enhance the spectrum of fundamental materials used for electrospinning. Unlike standard electrospun materials, our peptides are not polymeric, but able to aggregate in solution and especially during processing. They contain donor/acceptor groups that can form hydrogen bonds, and groups that are able to generate π-stacking interactions, which are known as important requirements for assembly processes. The pyrazole-isothiazole derivatives were synthesized by means of a 1,3-dipolar cycloaddition reaction, which is completely regioselective, affording only one isomer. We demonstrate that our compounds can be electrospun from fluoroalcohol solution into solid, quasi-endless micro- and nanofibers. The electrospinnability varies substantially, depending on the amino acids linked to the scaffold. Some compounds provide only short fibers, while Fmoc-glycyl-(N-benzyl)-pyrazole-isothiazole-tert-butyl carboxylate-1,1-dioxide forms continuous, homogenous, and bead-free fibers (droplet-like beads are a common problem in electrospinning). We analyzed the compounds and the fibers with various spectroscopic techniques (MS, IR and Raman). Electrospinning does not change chemical composition and configuration, suggesting the monomeric form of the compounds even in the fibers. Interestingly, we found that the stereochemistry of the scaffold can affect the ability of the peptide to be electrospun.

Graphical abstract: Electrospinning of pyrazole-isothiazole derivatives: nanofibers from small molecules

Supplementary files

Article information

Article type
Paper
Submitted
02 Apr 2019
Accepted
21 Jun 2019
First published
02 Jul 2019
This article is Open Access
Creative Commons BY-NC license

RSC Adv., 2019,9, 20565-20572

Electrospinning of pyrazole-isothiazole derivatives: nanofibers from small molecules

S. Locarno, A. Eleta-Lopez, M. G. Lupo, M. L. Gelmi, F. Clerici and A. M. Bittner, RSC Adv., 2019, 9, 20565 DOI: 10.1039/C9RA02486G

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