title: Gold nanoparticle flow sensors designed for dynamic X-ray imaging in biofluids.
abstract: X-ray-based imaging is one of the most powerful and convenient methods in terms of versatility in applicable energy and high performance in use. Different from conventional nuclear medicine imaging, contrast agents are required in X-ray imaging especially for effectively targeted and molecularly specific functions. Here, in contrast to much reported static accumulation of the contrast agents in targeted organs, dynamic visualization in a living organism is successfully accomplished by the particle-traced X-ray imaging for the first time. Flow phenomena across perforated end walls of xylem vessels in rice are monitored by a gold nanoparticle (AuNP) (approximately 20 nm in diameter) as a flow tracing sensor working in nontransparent biofluids. AuNPs are surface-modified to control the hydrodynamic properties such as hydrodynamic size (DH), zeta-potential, and surface plasmonic properties in aqueous conditions. Transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray nanoscopy (XN), and X-ray microscopy (XM) are used to correlate the interparticle interactions with X-ray absorption ability. Cluster formation and X-ray contrast ability of the AuNPs are successfully modulated by controlling the interparticle interactions evaluated as flow-tracing sensors.
authors.affiliation: Center for Biofluid and Biomimic Research, Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), San 31, Hyoja Dong, Namgu, Pohang 790-784, Korea.
authors.forename: Sungsook
authors.initials: S
authors.lastname: Ahn
authors.forename: Sung Yong
authors.initials: SY
authors.lastname: Jung
authors.forename: Jin Pyung
authors.initials: JP
authors.lastname: Lee
authors.forename: Hae Koo
authors.initials: HK
authors.lastname: Kim
authors.forename: Sang Joon
authors.initials: SJ
authors.lastname: Lee
mesh_terms: D000042:Absorption; D006046:Gold / Q000737:chemistry*; D057446:Hydrodynamics; D053768:Metal Nanoparticles / Q000737:chemistry*; D057054:Molecular Imaging / Q000379:methods*; D010316:Particle Size; D013499:Surface Properties; D013997:Time Factors; D014965:X-Rays
chemical_list: D006046:Gold