title: On the design of composite protein-quantum dot biomaterials via self-assembly.
abstract: Incorporation of nanoparticles during the hierarchical self-assembly of protein-based materials can impart function to the resulting composite materials. Herein we demonstrate that the structure and nanoparticle distribution of composite fibers are sensitive to the method of nanoparticle addition and the physicochemical properties of both the nanoparticle and the protein. Our model system consists of a recombinant enhanced green fluorescent protein-Ultrabithorax (EGFP-Ubx) fusion protein and luminescent CdSe-ZnS core-shell quantum dots (QDs), allowing us to optically assess the distribution of both the protein and nanoparticle components within the composite material. Although QDs favorably interact with EGFP-Ubx monomers, the relatively rough surface morphology of composite fibers suggests EGFP-Ubx-QD conjugates impact self-assembly. Indeed, QDs templated onto EGFP-Ubx film post-self-assembly can be subsequently drawn into smooth composite fibers. Additionally, the QD surface charge impacts QD distribution within the composite material, indicating that surface charge plays an important role in self-assembly. QDs with either positively or negatively charged coatings significantly enhance fiber extensibility. Conversely, QDs coated with hydrophobic moieties and suspended in toluene produce composite fibers with a heterogeneous distribution of QDs and severely altered fiber morphology, indicating that toluene severely disrupts Ubx self-assembly. Understanding factors that impact the protein-nanoparticle interaction enables manipulation of the structure and mechanical properties of composite materials. Since proteins interact with nanoparticle surface coatings, these results should be applicable to other types of nanoparticles with similar chemical groups on the surface.
authors: Material Science and Engineering Interdisciplinary Program, Texas A&M University, College Station, Texas 77843, United States.
authors: Ravish
authors: R
authors: Majithia
authors: Jan
authors: J
authors: Patterson
authors: Sarah E
authors: SE
authors: Bondos
authors: Kenith E
authors: KE
authors: Meissner
mesh_terms: D001672:Biocompatible Materials / Q000032:analysis / Q000138:chemical synthesis*; D040761:Biomimetic Materials / Q000032:analysis / Q000138:chemical synthesis*; D019187:Cadmium Compounds / Q000737:chemistry; D003001:Cloning, Molecular; D029721:Drosophila Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli; D031541:Fluorescence Resonance Energy Transfer; D049452:Green Fluorescent Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018398:Homeodomain Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D057927:Hydrophobic and Hydrophilic Interactions; D049449:Luminescence; D020894:Microfibrils / Q000737:chemistry; D053758:Nanoparticles / Q000737:chemistry; D010957:Plasmids; D045663:Quantum Dots; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018036:Selenium Compounds / Q000737:chemistry; D055672:Static Electricity; D013499:Surface Properties; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D014169:Transformation, Bacterial; D017967:Zinc Compounds / Q000737:chemistry
chemical_list: D001672:Biocompatible Materials; D019187:Cadmium Compounds; D029721:Drosophila Proteins; D018398:Homeodomain Proteins; D011993:Recombinant Fusion Proteins; D018036:Selenium Compounds; D014157:Transcription Factors; C066177:Ubx protein, Drosophila; D017967:Zinc Compounds; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins