I add enzyme to solution of graphene quantum dot , but I dont know when i can ensure that electrostatic attraction established.I cannt find a reliable method to confirm it.
Dear Abbasali,
The following paper cover the answer to your question.
1-http://www.ncbi.nlm.nih.gov/pubmed/17007529
Anal Chem. 2006 Oct 1;78(19):7022-6.
Enzyme-nanoparticle functionalization of three-dimensional protein scaffolds.
Hill RT1, Shear JB.
Author information
Abstract
Various surface modification techniques have been developed for patterning functional biomolecules in two dimensions, allowing enzymes, antibodies, and other compounds to be localized for applications in bioanalysis and bioengineering. Here, we report a strategy for extending high-resolution patterning of biomolecules to three dimensions. In this approach, three-dimensional protein scaffolds are created by a direct-write process in which multiphoton excitation promotes photochemical cross-linking of protein molecules from aqueous solution within specified volume elements. After scaffold fabrication, protein microstructures are functionalized with enzyme-gold nanoparticle conjugates via a targeting process based in part on electrostatic attraction between the low-isoelectric-point enzyme and the microstructure, fabricated from high-isoelectric-point proteins. High signal-to-background ratios (approximately 20:1) are demonstrated for fluorescent product streams created by dephosphorylation of the fluorogenic compound, fluorescein diphosphate, at microstructures decorated with alkaline phosphatase-gold nanoparticle conjugates. We also demonstrate feasibility for using such structures to quantify substrate concentrations in flowing streams with low-micromolar detection limits and to create sensor suites based on both enzyme-nanoparticle functionalization and intrinsic enzymatic activity of protein scaffolds. These topographically complex sensors and dosing sources have potential applications in microfluidics, sensor array fabrication, and real-time chemical modification of cell culture environments.
2-http://pubs.acs.org/doi/abs/10.1021/acsnano.5b03247?journalCode=ancac3
Shape-Dependent Biomimetic Inhibition of Enzyme by Nanoparticles and Their Antibacterial Activity
Sang-Ho Cha†‡, Jin Hong∥⊥, Matt McGuffie∥#, Bongjun Yeom†∥∇, J. Scott VanEpps*∥#, and Nicholas A. Kotov*†§∥
Enzyme inhibitors are ubiquitous in all living systems, and their biological inhibitory activity is strongly dependent on their molecular shape. Here, we show that small zinc oxide nanoparticles (ZnO NPs)—pyramids, plates, and spheres—possess the ability to inhibit activity of a typical enzyme β-galactosidase (GAL) in a biomimetic fashion. Enzyme inhibition by ZnO NPs is reversible and follows classical Michaelis–Menten kinetics with parameters strongly dependent on their geometry. Diverse spectroscopic, biochemical, and computational experimental data indicate that association of GAL with specific ZnO NP geometries interferes with conformational reorganization of the enzyme necessary for its catalytic activity. The strongest inhibition was observed for ZnO nanopyramids and compares favorably to that of the best natural GAL inhibitors while being resistant to proteases. Besides the fundamental significance of this biomimetic function of anisotropic NPs, their capacity to serve as degradation-resistant enzyme inhibitors is technologically attractive and is substantiated by strong shape-specific antibacterial activity against methicillin-resistant Staphylococcus aureus(MRSA), endemic for most hospitals in the world.
Keywords:
nanoparticles; enzymes; inhibitors; reaction kinetics; zinc oxide; ZnO;bacteria; MRSA
Hoping this will be helpful,
Rafik
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