Self‐assembly of thiolated versus non‐thiolated peptide amphiphiles

Elena A Egorova,Aimee L Boyle,Gert S Gooris,Prianka Luther,Alexander Kros,Joke A Bouwstra

doi:10.1002/pep2.24236

Elena A Egorova, Aimee L Boyle + Show 4 more

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https://doi.org/10.1002/pep2.24236

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Abstract

AbstractThe self‐assembly properties of peptide amphiphiles make them attractive for a range of applications, such as scaffolds for cell culture, drug delivery vehicles, or as stabilizing coatings for nanoparticles. The latter application requires derivatization of the amphiphiles to enable them to bind to, and interact with, a surface. This can be achieved by introduction of a thiol which facilitates binding to gold surfaces for example. However, small changes to the composition of peptide amphiphiles can have a large impact on their self‐assembly behavior. Therefore, we have synthesized and characterized a range of amphiphiles with different peptide sequences, alkyl chain lengths, and with or without a terminal thiol. We have characterized their structure and self‐assembly using circular dichroism (CD) spectroscopy, attenuated total reflection infrared (ATR‐IR) spectroscopy, and transmission electron microscopy (TEM). We discuss how changes to the peptide sequence and alkyl chain affect self‐assembly and compare the self‐assembly properties of thiolated and non‐thiolated amphiphiles. Such knowledge not only provides fundamental insights as to how self‐assembly can be controlled, but will also be helpful in determining which amphiphiles are most suitable for use as stabilizing nanoparticle coatings.

Highlights

Gold nanoparticles (GNPs) have a wide range of applications in areas such as drug delivery,[1] photothermal therapy,[2,3] and sensing.[4,5,6] GNPs are typically synthesized with a citrate coating, which is unstable under physiological conditions
The aim of this study is to investigate how the self-assembly of different peptide amphiphiles changes when they are modified with thiols
The composition of the peptide and alkyl chain segments of the peptide amphiphiles were altered in order to tune the physical and chemical properties to enable the investigation of these effects on selfassembly

Summary

Introduction

Gold nanoparticles (GNPs) have a wide range of applications in areas such as drug delivery,[1] photothermal therapy,[2,3] and sensing.[4,5,6] GNPs are typically synthesized with a citrate coating, which is unstable under physiological conditions. A different coating is required in order for GNPs to be used for biological applications.[7,8] Polymers[9,10,11] or silica[12,13,14] are commonly used for this purpose. The effective size of the GNPs is often significantly increased due to the thickness of these coatings.[14] low molecular weight molecules with stabilizing capabilities are of interest

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