title: Mechanism of proton relaxation for enzyme-manipulated, multicomponent gold-magnetic nanoparticle chains.
abstract: Longitudinal and transverse relaxation times of multicomponent nanoparticle (NP) chains are investigated for their potential use as multifunctional imaging agents in magnetic resonance imaging (MRI). Gold NPs (ca. 5 nm) are arranged linearly along double-stranded DNA, creating gold NP chains. After cutting gold NP chains with restriction enzymes (EcoRI or BamHI), multicomponent NP chains are formed through a ligation reaction with enzyme-cut, superparamagnetic NP chains. We evaluate the changes in relaxation times for different constructs of gold-iron oxide NP chains and gold-cobalt iron oxide NP chains using 300 MHz (1)H NMR. In addition, the mechanism of proton relaxation for multicomponent NP chains is examined. The results indicate that relaxation times are dependent on the one-dimensional structure and the amount of superparamagnetic NP chains present in the multicomponent constructs. Multicomponent NP chains arranged on double-stranded DNA provide a feasible method for fabrication of multifunctional imaging agents that improve relaxation times effectively for MRI applications.
authors.affiliation: Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA.
authors.forename: Hamsa
authors.initials: H
authors.lastname: Jaganathan
authors.forename: Richard L
authors.initials: RL
authors.lastname: Gieseck
authors.forename: Katherine
authors.initials: K
authors.lastname: Hudson
authors.forename: Michael
authors.initials: M
authors.lastname: Kellogg
authors.forename: Aneesh K
authors.initials: AK
authors.lastname: Ramaswamy
authors.forename: Kimberly E
authors.initials: KE
authors.lastname: Raver
authors.forename: Tyler
authors.initials: T
authors.lastname: Smith
authors.forename: Ashley N
authors.initials: AN
authors.lastname: Vacchiano
authors.forename: Andrew
authors.initials: A
authors.lastname: Wager
authors.forename: Albena
authors.initials: A
authors.lastname: Ivanisevic
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism; D003287:Contrast Media / Q000737:chemistry*; D004247:DNA / Q000737:chemistry* / Q000378:metabolism; D004262:DNA Restriction Enzymes / Q000378:metabolism; D006046:Gold / Q000737:chemistry*; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008280:Magnetics; D053758:Nanoparticles / Q000737:chemistry*; D011522:Protons
chemical_list: D001426:Bacterial Proteins; D003287:Contrast Media; D011522:Protons; D006046:Gold; D004247:DNA; D004262:DNA Restriction Enzymes