Dithiothreitol (DTT)-based displacement has been widely used for separating binding ligand conjugates from gold nanoparticles (AuNPs), a critical step in order to effectively quantify the functionality and dose of AuNP-based therapeutic platforms. In this study, we use a combination of dimensional (dynamic light scattering, electrospray-differential mobility analysis) and spectroscopic (attenuated total reflectance Fourier-transformed infrared spectroscopy) methods to characterize the efficacy of DTT-displacement. Thiolated polyethylene glycol (SH-PEG) and bovine serum albumin (BSA) were chosen as representative ligands for attachment to the AuNPs. The key results indicate that DTT does not completely displace the surface bound BSA and SH-PEG, and more importantly that the displacement ratio is dependent on the binding affinity between the conjugated ligands and the Au surface. Our work demonstrated here can be used as a prototype approach to quantitatively study the removal efficiency of other ligands, such as other proteins or deoxyribonucleic acid, from nanoparticles.

Quantifying dithiothreitol displacement of functional ligands from gold nanoparticles: Applications in nanomedicine

244th National Meeting (2012)

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