Prediction of Kinetically Stable Nanotheranostic Superstructures: Integral of First-Passage Times from Constrained Simulations

Abstract

The kinetics of forming multifunctional nanostructures, such as nanotheranostic superstructures, is often highly protracted, involving macroscopic time scales and resulting in nanostructures that correspond to kinetically stable states rather than thermodynamic equilibrium. Predicting such kinetically stable nanostructures becomes a great challenge due to the widely different, relevant time scales that are implicated in the formation kinetics of nano-objects. We develop a methodology, integral of first-passage times from constrained simulations (IFS), to predict kinetically stable, planet−satellite nanotheranostic superstructures. The simulation results are consistent with our experimental observations. The developed methodology enables the exploration of time scales from molecular vibrations of 10 −3 ns toward macroscopic scales, 10 10 ns, which permits the rational design and prediction of kinetically stable nanotheranostic superstructures for applications in nanomedicine.

Colorimetric Biosensors Based on Polymer/Gold Hybrid Nanoparticles: Topological Effects of the Polymer Coating

“…For comparably short arm lengths (similar to those of this study) in particular, it was revealed that during early stages of the star polymer molecule grafting process, attachment of free arms from already surface-anchored star polymer molecules is much faster than the surface attachment of free star polymer molecules. That is, initially, all star polymer molecules attach to the gold nanoparticle surface with all of their arm ends; only at later stages of the grafting process do newly attaching star polymer molecules maintain free arm ends (to covalently bind the maleimide-functionalized heparin). It can be expected that at these later stages, the surface grafting of the PEG-8arm-10k macromolecules will be much less efficient (due to their larger size) compared with the surface grafting of PEG-4arm-5k macromolecules, and thus more free arm ends will result from the grafting of PEG-4arm-5k macromolecules.…”

“…This end group density in the exterior of the polymer layer is controlled in the star polymer surface grafting process, which initially involves the star polymer molecule surface attachment with one arm end, and, eventually, the surface attachment of all or a fraction of the remaining arm ends. Both processes are kinetically controlled, and the associated barriers dynamically build up during the grafting process . For comparably short arm lengths (similar to those of this study) in particular, it was revealed that during early stages of the star polymer molecule grafting process, attachment of free arms from already surface-anchored star polymer molecules is much faster than the surface attachment of free star polymer molecules.…”

“…Both processes are kinetically controlled, and the associated barriers dynamically build up during the grafting process. 29 For comparably short arm lengths (similar to those of this study) in particular, it was revealed 29 that during early stages of the star polymer molecule grafting process, attachment of free arms from already surface-anchored star polymer molecules is much faster than the surface attachment of free star polymer molecules. That is, initially, all star polymer molecules attach to the gold nanoparticle surface with all of their arm ends; 29 only at later stages of the grafting process do newly attaching star polymer molecules maintain free arm ends (to covalently bind the maleimide-functionalized heparin).…”

Fabrication of Polymer-Metal Nanohybrids - Routes Towards Functional Materials

“…[10,11] Within the last decade, the Vana-group presented outstanding science in the world of nanocomposites. Various metal nanocrystals from gold, [12][13][14][15][16][17][18] silver [19,20] and palladium [21] as well as silica nanoparticles [22] could be functionalized with tailored macromolecules. In this context, their self-assembly into 2D nanostructered surfaces, 3D superstructures and planet−satellite structures was studied intensively.…”

“…18 and by comparing the spacing shown in Tables 5.4 and 5.5 the spacing-ratios of the respective Pd-polymer-nanohybrids and the Pd-planet-Au-satellite structures, range from 0.47 -0.61. Taking into account the standard deviations up to ~20% ratios stay in good agreement with the expected values.…”