title: Quantifying the nanomachinery of the nanoparticle-biomolecule interface.
abstract: A study is presented of the nanomechanical phenomena experienced by nanoparticle-conjugated biomolecules. A thermodynamic framework is developed to describe the binding of thrombin-binding aptamer (TBA) to thrombin when the TBA is conjugated to nanorods. Binding results in nanorod aggregation (viz. directed self-assembly), which is detectable by absorption spectroscopy. The analysis introduces the energy of aggregation, separating it into TBA-thrombin recognition and surface-work contributions. Consequently, it is demonstrated that self-assembly is driven by the interplay of surface work and thrombin-TBA recognition. It is shown that the work at the surface is about -10 kJ mol(-1) and results from the accumulation of in-plane molecular forces of pN magnitude and with a lifetime of <1 s, which arises from TBA nanoscale rearrangements fuelled by thrombin-directed nanorod aggregation. The obtained surface work can map aggregation regimes as a function of different nanoparticle surface conditions. Also, the thermodynamic treatment can be used to obtain quantitative information on surface effects impacting biomolecules on nanoparticle surfaces.
authors.affiliation: Department of Biological Engineering and the Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA, 02139, USA; Institut Quimic de Sarrià, Universitat Ramon Llull Via Augusta 390, 08017 Barcelona, Spain.
authors.forename: Helena
authors.initials: H
authors.lastname: de Puig
authors.forename: Stefania
authors.initials: S
authors.lastname: Federici
authors.forename: Salmaan H
authors.initials: SH
authors.lastname: Baxamusa
authors.forename: Paolo
authors.initials: P
authors.lastname: Bergese
authors.forename: Kimberly
authors.initials: K
authors.lastname: Hamad-Schifferli
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry; D001696:Biomechanical Phenomena; D006046:Gold / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry / Q000648:ultrastructure; D036103:Nanotechnology; D043942:Nanotubes / Q000737:chemistry / Q000648:ultrastructure; D011485:Protein Binding; D013499:Surface Properties; D013816:Thermodynamics; D013917:Thrombin / Q000037:antagonists & inhibitors / Q000737:chemistry
chemical_list: D052157:Aptamers, Nucleotide; C081676:thrombin aptamer; D006046:Gold; D013917:Thrombin