Biomolecular binding

We selected the streptavidin-biotin binding interaction for proof-of-concept studies of the immobilized nanoSPR sensor for the following reasons first, because of its very high association constant, streptavidin-biotin binding is insensitive to washing steps, which simplifies the experimental setup. Second, the wide use of this model system for validation of other biosensors enables comparison of the nanoSPR biosensor with other platforms under development.  

A monolayer of 13.4 nm gold nanoparticles on glass was functionalized by formation of a SAM of 3-mercaptopropionic acid (MPA) to present terminal COOH groups at the surface of the gold nanoparticles. The COOH groups were then activated with a 1 1 mixture of l-ethyl-3-(dimethylamino)propyl carbodiimide (EDAC) and 

---

Goh, J. B. Loo, R. W. Goh, M. C., Label free monitoring of multiple biomolecular binding interactions in real time with diffraction based sensing, Sens. Actuators B Chem. 2005, 106, 243 248... 

Xu, D. X. Densmore, A. Delage, A. Waldron, P. Janz, S. Lapointe, J. Lopinski, G. Mischki, T. McKinnon, R. Cheben, P. Schmid, J. H., Folded cavity SOI microring resonator sensors for high sensitivity and real time measurement of biomolecular binding, Opt. Express 2008, 16, 15137 15148... 

Li, Z., Lazaridis, T. (2007) Water at biomolecular binding interfaces. Phys Chem ChemPhys9, 573-581. 

In most cases, the test compounds are dissolved in DMSO and are added from a source plate into the assay. Thus, the tolerance of the assay for DMSO should be tested, by looking at the activities at various increasing concentrations of DMSO. Generally, enzymatic or biomolecular binding assays are more tolerant of high DMSO concentrations (often up to 5% to 10% DMSO). Cell-based assays usually can tolerate up to 0.5% DMSO. 

Campbell CT, Kim G (2007) SPR microscopy and its applications to high-throughput analyses of biomolecular binding events and their kinetics. Biomaterials 28 2380-2392... 

Most biomolecular binding events occur on timescales orders of magnitude greater than can be attained in standard molecular dynamics simulations in which the motion of all atoms is... 

Pan S, Rothberg LJ (2003) Interferometric sensing of biomolecular binding using nanoporous aluminum oxide templates. Nano Lett 3 811-814... 

This reflectivity measurement may then be analyzed to obtain a measurement of biomolecular binding in real-time. 

Riley, K. E., Pitonak, M., Cerny,)., and Hobza, P. On the stmcture and geometry of biomolecular binding motifs (hydrogen-bonding, stacking, X-H center dot center dot center dot pi) WFT and DFT calculations. J. Chem. Theory Comput, 6, 66-80, doi 10.1021/ct900376r (2010). 

Lanthanide chelate-dyed polystyrene particles containing carboxylic acid groups have been covalently coated with antibodies, streptavidin [95], and nucleic acids [96] for different biomolecular-binding assays. Particulate labels can be coated with antibodies and used as such, but the obvious steric and kinetic problems associated with the large molecular size can be particularly avoided by indirect detection of the bound antibodies using, e.g., biotin-streptavidin interaction [97,... 

Jans H, Liu X, Huo Q, Austin L, Maes G (2009) Dynamic light scattering as a powerful tool fcff gold nanoparticle bioconjugation and biomolecular binding studies. Anal Chem 81 9425-9432... 

The previous discussion has focused on the fabrication, characterization and optimization of the transducer. Here, we discuss, coupling of the biomolecular detector to the optical transducer to create a functional nanoSPR biosensor. The two important steps in coupling the biological detector to the optical transducer are presentation of the receptor on the nanoparticle surface and biomolecular binding between receptor and analyte. It has been shown that the density and spatial distribution of the receptor on the surface influences the effective binding affinity of the biomolecular recognition interaction as well as the surface density of the biomolecular complex, so that... 

---