Protein crystal based materials for nanoscale applications in medicine and biotechnology.

The porosity, order, biocompatibility, and chirality of protein crystals has motivated interest from diverse research domains including materials science, biotechnology, and medicine. Porous protein crystals have the unusual potential to organize guest molecules within highly ordered scaffolds, enabling applications ranging from biotemplating and catalysis to biosensing and drug delivery. Significant research has therefore been directed toward characterizing protein crystal materials in hopes of optimizing crystallization, scaffold stability, and application efficacy.

Characterizing the Cytocompatibility of Various Cross-Linking Chemistries for the Production of Biostable Large-Pore Protein Crystal Materials.

With rapidly growing interest in therapeutic macromolecules, targeted drug delivery, and in vivo biosensing comes the need for new nanostructured biomaterials capable of macromolecule storage and metered release that exhibit robust stability and cytocompatibility. One novel possibility for such a material are engineered large-pore protein crystals (LPCs). Here, various chemically stabilized LPC derived biomaterials were generated using three cross-linking agents: glutaraldehyde, oxaldehyde, and 1-ethyl-3-(3-(dimethylamino)propyl)carbodiimide.

Adsorption-Coupled Diffusion of Gold Nanoclusters within a Large-Pore Protein Crystal Scaffold.

Large-pore protein crystals (LPCs) are ordered biologically derived nanoporous materials exhibiting pore diameters greater than 8 nm. These substantial pores distinguish LPCs from typical nanoporous scaffolds, enabling engineered LPC materials to readily uptake, immobilize, and release macromolecular guests. In this study, macromolecular transport within an LPC environment was experimentally and computationally investigated by studying adsorption-coupled diffusion of Au(glutathione) nanoclusters within a cross-linked LPC scaffold via time-lapse confocal microscopy, bulk equilibrium adsorption, and hindered diffusion simulation.

Programmed Assembly of Host-Guest Protein Crystals.

The binding and release of guest fluorescent proteins inside a protein crystal with 13 nm axial pores is controlled. Spatially segregated guest protein loading is achieved via sequential binding and release stages. Additionally, selective stabilization of the crystal exterior results in hollow crystalline shells.

Gold nanoparticle capture within protein crystal scaffolds.

DNA assemblies have been used to organize inorganic nanoparticles into 3D arrays, with emergent properties arising as a result of nanoparticle spacing and geometry. We report here the use of engineered protein crystals as an alternative approach to biologically mediated assembly of inorganic nanoparticles. The protein crystal's 13 nm diameter pores result in an 80% solvent content and display hexahistidine sequences on their interior.