title: The intersection of CMOS microsystems and upconversion nanoparticles for luminescence bioimaging and bioassays.
abstract: Organic fluorophores and quantum dots are ubiquitous as contrast agents for bio-imaging and as labels in bioassays to enable the detection of biological targets and processes. Upconversion nanoparticles (UCNPs) offer a different set of opportunities as labels in bioassays and for bioimaging. UCNPs are excited at near-infrared (NIR) wavelengths where biological molecules are optically transparent, and their luminesce in the visible and ultraviolet (UV) wavelength range is suitable for detection using complementary metal-oxide-semiconductor (CMOS) technology. These nanoparticles provide multiple sharp emission bands, long lifetimes, tunable emission, high photostability, and low cytotoxicity, which render them particularly useful for bio-imaging applications and multiplexed bioassays. This paper surveys several key concepts surrounding upconversion nanoparticles and the systems that detect and process the corresponding luminescence signals. The principle of photon upconversion, tuning of emission wavelengths, UCNP bioassays, and UCNP time-resolved techniques are described. Electronic readout systems for signal detection and processing suitable for UCNP luminescence using CMOS technology are discussed. This includes recent progress in miniaturized detectors, integrated spectral sensing, and high-precision time-domain circuits. Emphasis is placed on the physical attributes of UCNPs that map strongly to the technical features that CMOS devices excel in delivering, exploring the interoperability between the two technologies.
authors.affiliation: Department of Physics and Materials Science, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong. weiliping1988@gmail.com.
authors.forename: Liping
authors.initials: L
authors.lastname: Wei
authors.affiliation: Department of Chemical and Physical Sciences, University of Toronto Mississauga, 3359 Mississauga Road North, Mississauga, Ontario L5L 1C6, Canada. samer.doughan@utoronto.ca.
authors.forename: Samer
authors.initials: S
authors.lastname: Doughan
authors.affiliation: Department of Chemical and Physical Sciences, University of Toronto Mississauga, 3359 Mississauga Road North, Mississauga, Ontario L5L 1C6, Canada. yi.han@utoronto.ca.
authors.forename: Yi
authors.initials: Y
authors.lastname: Han
authors.affiliation: Department of Chemical and Physical Sciences, University of Toronto Mississauga, 3359 Mississauga Road North, Mississauga, Ontario L5L 1C6, Canada. matt.dacosta@utoronto.ca.
authors.forename: Matthew V
authors.initials: MV
authors.lastname: DaCosta
authors.affiliation: Department of Chemical and Physical Sciences, University of Toronto Mississauga, 3359 Mississauga Road North, Mississauga, Ontario L5L 1C6, Canada. ulrich.krull@utoronto.ca.
authors.forename: Ulrich J
authors.initials: UJ
authors.lastname: Krull
authors.affiliation: Department of Physics and Materials Science, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong. weiliping1988@gmail.com.
authors.forename: Derek
authors.initials: D
authors.lastname: Ho
mesh_terms: D001681:Biological Assay / Q000295:instrumentation*; D015374:Biosensing Techniques / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008163:Luminescent Measurements / Q000295:instrumentation*; D057054:Molecular Imaging / Q000295:instrumentation*; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D036103:Nanotechnology / Q000295:instrumentation; D045663:Quantum Dots; D012666:Semiconductors; D018511:Systems Integration