Selection of Arginine-Rich Anti-Gold Antibodies Engineered for Plasmonic Colloid Self-Assembly

Abstract

34p ; This document is the unedited author's version of a Submitted Work that was subsequently accepted for publication in J. Phys. Chem. C, copyright © American Chemical Society after peer review. To access the final edited and published work, see http://pubs.acs.org/doi/abs/10.1021/jp502118n.Antibodies are affinity proteins with a wide spectrum of applications in analytical and therapeutic biology. Proteins showing specific recognition for a chosen molecular target can be isolated and their encoding sequence identified in vitro from a large and diverse library by phage display selection. In this work, we show that this standard biochemical technique rapidly yields a collection of antibody protein binders for an inorganic target of major technological importance: crystalline metallic gold surfaces. 21 distinct anti-gold antibody proteins emerged from a large random library of antibodies and were sequenced. The systematic statistical analysis of all the protein sequences reveals a strong occurrence of arginine in anti-gold antibodies, which corroborates recent molecular dynamics predictions on the crucial role of arginine in protein/gold interactions. Once tethered to small gold nanoparticles using histidine tag chemistry, the selected antibodies could drive the self-assembly of the colloids onto the surface of single crystalline gold platelets as a first step towards programmable protein-driven construction of complex plasmonic architectures. Electrodynamic simulations based on the Green Dyadic Method suggest that the antibody-driven assembly demonstrated here could be exploited to significantly modify the plasmonic modal properties of the gold platelets. Our work shows that molecular biology tools can be used to design the interaction between fully folded proteins and inorganic surfaces with potential applications in the bottom-up construction of plasmonic hybrid nanomaterials

Affinity and Selectivity of Peptides for Inorganic Materials: A Thermodynamic Discussion of the Role of Conformational Flexibility

“…For example, in Ref. 18, a high content of arginine has been found for gold-specific antibodies, which is in agreement with previous experiments and simulations. [24][25][26][27][28][29][30]45 Arty-Schnirman et al 14 demonstrated the capability of biocombinatorially selected antibodies to recognize both a material and a specific crystal face of such material.…”

“…Both peptides 11,12,15 (called genetically-engineered peptides for inorganics, GEPIs) and entire proteins (antibodies) 13,[16][17][18] able to select (in the differential affinity sense clarified previously) inorganic surfaces have been obtained by cleverly adapting combinatorial biology and bioinformatics techniques to inorganic targets. Thanks to an ongoing effort that combines experiments and atomistic modeling, 19,20 the microscopic determinants of peptide/inorganic affinity and of selectivity are being clarifying for various materials, although the full picture is still far from being complete.…”

Modal engineering of Surface Plasmons in apertured Au Nanoprisms

“…Henceforth, modal engineering can be envisioned if one can perturb the spectral or spatial distributions of the free electron density oscillations inside the plasmonic cavity. In the conceptual limit where the size of one of the two coupled colloids is reduced down to a Rayleigh particle, the presence of this small polarizable metallic object distorts the SP-LDOS in the remaining plasmonic system 14 .…”

Functional and Selective Bacterial Interfaces Using Cross-Scaffold Gold Binding Peptides

“…Willett et al systematically tabulated single amino acid adhesion to a variety of inorganic materials, where it was noted empirically that only amino acid residues Arg, Thr, Asp, Ser, Ile, and Pro displayed much affinity for the non-oxide-forming gold surface. 47 Arginine-rich sequences have also been found in the engineered antibody work of Jain et al 48 We note that cysteine is prominently missing from this list, despite the ubiquity of the thiol-gold interaction in the field of self-assembled monolayers (SAMs) and the spectroscopic identification of the sulfur-gold bond in other cysteine-containing gold systems. 49 However, relative rankings of amino acids as gold binders in additional work (such as that of Peelle et al, 50 Fears et al 51 and Cohavi 52 ) have not displayed consistent trends.…”