Nanomechanical characterization of chemical interaction between gold nanoparticles and chemical functional groups

Gyudo Lee,Hyungbeen Lee,Sang Woo Lee,Dae Sung Yoon,Jaemoon Yang,Kihwan Nam,Taeyun Kwon,Kilho Eom,Jae-Hee Han

doi:10.1186/1556-276x-7-608

Gyudo Lee, Hyungbeen Lee + Show 7 more

Open Access

https://doi.org/10.1186/1556-276x-7-608

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Abstract

We report on how to quantify the binding affinity between a nanoparticle and chemical functional group using various experimental methods such as cantilever assay, PeakForce quantitative nanomechanical property mapping, and lateral force microscopy. For the immobilization of Au nanoparticles (AuNPs) onto a microscale silicon substrate, we have considered two different chemical functional molecules of amine and catecholamine (here, dopamine was used). It is found that catecholamine-modified surface is more effective for the functionalization of AuNPs onto the surface than the amine-modified surface, which has been shown from our various experiments. The dimensionless parameter (i.e., ratio of binding affinity) introduced in this work from such experiments is useful in quantitatively depicting such binding affinity, indicating that the binding affinity and stability between AuNPs and catecholamine is approximately 1.5 times stronger than that between amine and AuNPs. Our study sheds light on the experiment-based quantitative characterization of the binding affinity between nanomaterial and chemical groups, which will eventually provide an insight into how to effectively design the functional material using chemical groups.

Highlights

Surface chemistry has played a critical role in designing functional nanomaterials for their biological or medical applications such as drug delivery, molecular therapeutics, and diagnostics [1,2]
Since the surface modification of nanomaterials using Dopamine hydrochloride (DOPA) typically employs a noncovalent conjugation [6,26], it is essential to establish an experimental framework that allows for measuring a weak binding affinity corresponding to such a noncovalent conjugation, which is useful in the development of drug carrier due to the fact that noncovalent conjugation enables the excretion of waster matter from the human body after the drug carrier completes the function of drug delivery or bioimaging [6,7,27,28]
We have introduced a dimensionless parameter defined as RF = FD/FA, where FA indicates the lateral force between Gold nanoparticle (AuNP) and surface of the cantilever (SA), and FD represents the lateral force between AuNPs and DOPA-modified surface (SD)

Summary

Introduction

Surface chemistry has played a critical role in designing functional nanomaterials for their biological or medical applications such as drug delivery, molecular therapeutics, and diagnostics [1,2]. The surface modification of a nanoparticle is of great importance to enhancing functionality in terms of target affinity [3,4,5], imaging contrast [3,4,6,7], and curative power [8]. DOPA has been reported as a chemical linker that is useful in the chemical modification of the surfaces of nanomaterials such as nanoparticles [18,19], graphene oxide sheet [20], and carbon nanotubes [21], and in improving binding affinities such as protein-peptide cross-linking [22], cellular adhesion to substrate [23], osteoconduction [24], and hemostatic adhesive in segmentectomy [25]. Since the surface modification of nanomaterials using DOPA typically employs a noncovalent conjugation (e.g., coordinate bonding, hydrophobic and electrostatic interactions, etc.) [6,26], it is essential to establish an experimental framework that allows for measuring a weak binding affinity corresponding to such a noncovalent conjugation, which is useful in the development of drug carrier due to the fact that noncovalent conjugation enables the excretion of waster matter from the human body after the drug carrier completes the function of drug delivery or bioimaging [6,7,27,28]

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