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Atomistic Simulations of Functionalized Nano-Materials for Biosensors Applications
 
 
Article

Role of Ionic Strength in the Formation of Stable Supramolecular Nanoparticle–Protein Conjugates for Biosensing

1
Institute of Nanoscience, CNR-NANO S3, via G. Campi 213/A, 41125 Modena, Italy
2
Department of Chemistry, University of Massachusetts, 710 North Pleasant Street, Amherst, MA 01003, USA
3
Department of Chemical Sciences, University of Padova, via Marzolo 1, 35131 Padova, Italy
*
Author to whom correspondence should be addressed.
Academic Editor: Mahmoud Ghomi
Int. J. Mol. Sci. 2022, 23(4), 2368; https://doi.org/10.3390/ijms23042368
Received: 14 January 2022 / Revised: 11 February 2022 / Accepted: 14 February 2022 / Published: 21 February 2022
(This article belongs to the Special Issue Molecular Simulations of Functionalized Nanoscale Materials)
Monolayer-protected gold nanoparticles (AuNPs) exhibit distinct physical and chemical properties depending on the nature of the ligand chemistry. A commonly employed NP monolayer comprises hydrophobic molecules linked to a shell of PEG and terminated with functional end group, which can be charged or neutral. Different layers of the ligand shell can also interact in different manners with proteins, expanding the range of possible applications of these inorganic nanoparticles. AuNP-fluorescent Green Fluorescent Protein (GFP) conjugates are gaining increasing attention in sensing applications. Experimentally, their stability is observed to be maintained at low ionic strength conditions, but not at physiologically relevant conditions of higher ionic strength, limiting their applications in the field of biosensors. While a significant amount of fundamental work has been done to quantify electrostatic interactions of colloidal nanoparticle at the nanoscale, a theoretical description of the ion distribution around AuNPs still remains relatively unexplored. We perform extensive atomistic simulations of two oppositely charged monolayer-protected AuNPs interacting with fluorescent supercharged GFPs co-engineered to have complementary charges. These simulations were run at different ionic strengths to disclose the role of the ionic environment on AuNP–GFP binding. The results highlight the capability of both AuNPs to intercalate ions and water molecules within the gold–sulfur inner shell and the different tendency of ligands to bend inward allowing the protein to bind not only with the terminal ligands but also the hydrophobic alkyl chains. Different binding stability is observed in the two investigated cases as a function of the ligand chemistry. View Full-Text
Keywords: molecular dynamics; multiscale modeling; ionic strength; biosensors; functionalized metal nanoparticles; supercharged GFP molecular dynamics; multiscale modeling; ionic strength; biosensors; functionalized metal nanoparticles; supercharged GFP
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MDPI and ACS Style

Brancolini, G.; Rotello, V.M.; Corni, S. Role of Ionic Strength in the Formation of Stable Supramolecular Nanoparticle–Protein Conjugates for Biosensing. Int. J. Mol. Sci. 2022, 23, 2368. https://doi.org/10.3390/ijms23042368

AMA Style

Brancolini G, Rotello VM, Corni S. Role of Ionic Strength in the Formation of Stable Supramolecular Nanoparticle–Protein Conjugates for Biosensing. International Journal of Molecular Sciences. 2022; 23(4):2368. https://doi.org/10.3390/ijms23042368

Chicago/Turabian Style

Brancolini, Giorgia, Vincent M. Rotello, and Stefano Corni. 2022. "Role of Ionic Strength in the Formation of Stable Supramolecular Nanoparticle–Protein Conjugates for Biosensing" International Journal of Molecular Sciences 23, no. 4: 2368. https://doi.org/10.3390/ijms23042368

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