ABSTRACT
Combined near-infrared (NIR) fluorescence and photoacoustic imaging techniques present promising capabilities for noninvasive visualization of biological structures. Development of bimodal noninvasive optical imaging approaches by combining NIR fluorescence and photoacoustic tomography demands suitable NIR-active exogenous contrast agents. If the aggregation and photobleaching are prevented, squaraine dyes are ideal candidates for fluorescence and photoacoustic imaging. Herein, we report rational selection, preparation, and micelle encapsulation of an NIR-absorbing squaraine dye (D1) for in vivo fluorescence and photoacoustic bimodal imaging. D1 was encapsulated inside micelles constructed from a biocompatible nonionic surfactant (Pluoronic F-127) to obtain D1-encapsulated micelles (D1(micelle)) in aqueous conditions. The micelle encapsulation retains both the photophysical features and chemical stability of D1. D1(micelle) exhibits high photostability and low cytotoxicity in biological conditions. Unique properties of D1(micelle) in the NIR window of 800-900 nm enable the development of a squaraine-based exogenous contrast agent for fluorescence and photoacoustic bimodal imaging above 820 nm. In vivo imaging using D1(micelle), as demonstrated by fluorescence and photoacoustic tomography experiments in live mice, shows contrast-enhanced deep tissue imaging capability. The usage of D1(micelle) proven by preclinical experiments in rodents reveals its excellent applicability for NIR fluorescence and photoacoustic bimodal imaging.
Subject(s)
Cyclobutanes/chemistry , Fluorescence , Fluorescent Dyes/chemistry , Micelles , Molecular Imaging/methods , Phenols/chemistry , Photoacoustic Techniques , Animals , Cell Line, Tumor , Cell Survival , Female , Humans , Mice , Mice, SCID , Optical ImagingABSTRACT
An inclusion complex of NaYF4 :Yb(3+) ,Er(3+) upconversion nanoparticles with α-cyclodextrin in aqueous conditions exhibits luminescence quenching when excited at 980 nm. This non-radiative relaxation leads to an unprecedented photoacoustic signal enhancement. In vivo localization of α-cyclodextrin-covered NaYF4 :Yb(3+) ,Er(3+) is demonstrated using photoacoustic tomography in live mice, showing its high capability for photoacoustic imaging.
Subject(s)
Contrast Media , Nanoparticles , Photoacoustic Techniques/methods , Tomography/methods , Animals , Cell Survival/drug effects , Contrast Media/adverse effects , Contrast Media/chemistry , Cyclohexanes/chemistry , Female , HeLa Cells , Humans , Luminescence , Mice, SCID , Models, Biological , Nanoparticles/adverse effects , Nanoparticles/chemistry , Phantoms, Imaging , Photoacoustic Techniques/instrumentation , Solvents/chemistry , Tomography/instrumentation , Water/chemistry , alpha-Cyclodextrins/chemistryABSTRACT
A new and efficient method of obtaining homopropargylic alcohols via homopropargylic transfer from the allenic alcohol to various aldehydes in the presence of Lewis acid catalysts is described; stereochemical studies have shown that this process is the first oxonium [3,3]-sigmatropic rearrangement of an allenic alcohol to a homopropargylic alcohol in the presence of aldehydes and Lewis acid.
Subject(s)
Aldehydes/chemistry , Alkynes/chemical synthesis , Silicon/chemistry , Alkynes/chemistry , Molecular Structure , Propanols/chemistryABSTRACT
High regioselective preparation of either the allenic alcohols or homopropargylic alcohols using the indium-mediated reaction of trialkylsilyl propargyl bromides with various aldehydes has been accomplished. By just changing the silyl groups and the reaction conditions, both the allenic and homopropargylic alcohols can be obtained in high regioselectivities.
