tailieunhanh - báo cáo khoa học: " Highly Active Engineered-Enzyme Oriented Monolayers: Formation, Characterization and Sensing Applications"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành y học dành cho các bạn tham khảo đề tài: Highly Active Engineered-Enzyme Oriented Monolayers: Formation, Characterization and Sensing Applications | Ulman et al. Journal of Nanobiotechnology 2011 9 26 http content 9 1 26 JOURNAL OF NANOBIOTECHNOLOGY RESEARCH Open Access Highly Active Engineered-Enzyme Oriented Monolayers Formation Characterization and Sensing Applications 14 1 23 1 Abraham Ulman 1 Michael Ioffe Fernando Patolsky Elisha Haas and Dana Reuvenov Abstract Background The interest in introducing ecologically-clean and efficient enzymes into modern industry has been growing steadily. However difficulties associated with controlling their orientation and maintaining their selectivity and reactivity is still a significant obstacle. We have developed precise immobilization of biomolecules while retaining their native functionality and report a new fast easy and reliable procedure of protein immobilization with the use of Adenylate kinase as a model system. Methods Self-assembled monolayers of hexane-1 6-dithiol were formed on gold surfaces. The monolayers were characterized by contact-angle measurements Elman-reagent reaction QCM and XPS. A specifically designed mutated Adenylate kinase where cysteine was inserted at the 75 residue and the cysteine at residue 77 was replaced by serine was used for attachment to the SAM surface via spontaneously formed disulfide S-S bonds. QCM and XPS were used for characterization of the immobilized protein layer. Curve fitting in XPS measurements used a Gaussian-Lorentzian function. Results and Discussion Water contact angle 65-70 as well as all characterization techniques used confirmed the formation of self-assembled monolayer with surface SH groups. X-ray photoelectron spectroscopy showed clearly the two types of sulfur atom one attached to the gold triolate and the other SH S-S at the m position for the hexane-1 6-dithiol SAMs. The formation of a protein monolayer was confirmed using XPS and QCM where the QCM-determined amount of protein on the surface was in agreement with a model that considered the surface area of a single protein .