Protein - Nanoparticles Interaction

When gold nanoparticles (AuNPs) come in contact with a biological medium, proteins interact with the AuNP surface creating a layer around it. This layer is called "corona" and confers to the NPs a new "biological identity" which determines the subsequent cellular/tissue response. The corona doesn't reach immediately the equilibrium: in the early stage, when the AuNPs encounter for the first time the biological medium, proteins with high concentrations and high association rate constants adsorb on the NPs surface, but they dissociate quickly. In fact, they are replaced by proteins with lower concentrations, with slower exchange rate constant, but with higher affinity (Vroman's effect).

Proteins that adsorb with high affinity form an inner layer consisting of tightly bound proteins (the "hard corona"). Proteins that absorb with low affinity form an outer layer consisting of loosely bound proteins (the "soft corona").

Figure 1: Ubiquitins interacting with a gold nanoparticle. Ubiquitins are rendered with different colors.[1]

Figure 2: Interaction of insulins and fibrinogen with a gold nanoparticle.[2]

It is founded that absorbed proteins undergo conformational changes depending on the NPs size and shape and on surface charges decreasing the percentage of helices. This lead to a change in their function and, consequently, to health diseases. 

Coarse Grained (CG) models are powerful tools to investigate big system, such a AuNP covered by the bio-corona, for long timescales.

Formation of the insulin corona around a 5nm diameter gold nanoparticle using Coarse Grained Molecular Dynamics Simulations [2].

Interaction of a fibrinogen with two gold nanoparticles by CG MD simulations [2].

Formation of the DARP-in corona around a 5nm diameter gold nanoparticle using Coarse Grained Molecular Dynamics Simulations [3].

- [1] F. Tavanti, A. Pedone and M. C. Menziani. A closer look into the ubiquitin corona formation on gold nanoparticles by computational studies. , New. J. Chem, 2015, 39, 2474-2482

- [2] F. Tavanti, A. Pedone, M. C. Menziani, Competitive Binding of Proteins to Gold Nanoparticles disclosed by Molecular Dynamics Simulations, J. Phys. Chem. C, 2015, 119, 22172-22180

- [3] Sergey Deyev, Galina Proshkina, Anastasiya Ryabova, Francesco Tavanti, Maria Cristina Menziani, Gennady Eidelshtein, Gabriel Avishai, Alexander B Kotlyar, Synthesis, Characterization and Selective Delivery of DARPin-Gold Nanoparticle Conjugates to Cancer Cells, Bioconjiugate Chemistry, 2017, just accepted.