DNA-templated nanoparticle (NP) chains were examined as potential magnetic resonance imaging (MRI) contrast agents using in vitro environments of the extracellular matrix and tissue. A 3-T clinical MRI scanner was utilized to examine and compare image contrast enhanced by dispersed NPs, DNA-templated NP chains, gold-superparamagnetic multicomponent NP chains, and polyelectrolyte encapsulated, multicomponent NP chains in both T(1)-weighted and T(2)-weighted images. In addition, the longitudinal and transverse relaxivity (r(1) and r(2)) changes were measured both in the basement membrane, using Matrigel, and in the tissue environment, using in vitro 3D cell culture scaffolds. Results suggest that MRI contrast was significantly enhanced from NP chains compared to dispersed NPs in the basement membrane and polyelectrolyte encapsulation for NP chains produced similar relaxivity to nonencapsulated NP chains due to the enhanced cell uptake of encapsulated NP chains.

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Fourier transform infrared (FT-IR) spectroscopy is utilized to observe adsorbate interactions with a tissue-derived collagen scaffold extracted from the Bruch's membrane of pig eyes. The characterization includes conformational changes in isoleucine, polyisoleucine, collagen-binding peptide, RGD-tagged collagen-binding peptide, and laminin after adsorption onto the substrate. Isotopically labeled isoleucine is further utilized to understand changes in the biomolecular structure upon binding to a tissue-derived surface. The adsorbates associated with the collagen scaffold predominately through hydrophobic interactions and hydrogen bonding. The results of this study can be used to improve our understanding of surface chemistry changes during the engineering of biomimetic scaffolds before and after biomolecule adsorption.