Langmuir analysis of nanoparticle polyvalency in DNA-mediated adsorption

Many nanoparticle adsorption processes are dictated by the collective interactions of surface-bound ligands. These adsorption processes define how nanoparticles interact with biological systems and enable the assembly of nanoparticle-based materials and devices. Herein, we present an approach for quantifying nanoparticle adsorption thermodynamics in a manner that satisfies the assumptions of the Langmuir model. Using this approach, we study the DNA-mediated adsorption of polyvalent anisotropic nanoparticles on surfaces and explore how deviations from model assumptions influence adsorption thermodynamics. Importantly, when combined with a solution-based van't Hoff analysis, we find that polyvalency plays a more important role as the individual interactions become weaker. Furthermore, we find that the free energy of anisotropic nanoparticle adsorption is consistent across multiple shapes and sizes of nanoparticles based on the surface area of the interacting facet. Stuck on Au: A model system is defined that allows the quantification of nanoparticle adsorption energy under conditions that satisfy the assumptions of the Langmuir adsorption model. This advance could enable fundamental studies of nanoparticles relating to adsorption chemistry, biological processes, and materials by design.