title: Optical methods.
abstract: Molecular imaging requires the highest possible signal-to-noise ratios (SNRs) at the target of interest. In order to maximize the SNR for optical imaging techniques, various strategies have been developed to design fluorescent probes that can be activated, for example, by proteolytic degradation. Generally speaking, these probes are quenched in their native state-e.g., by fluorescence resonance energy transfer (FRET)-and dequenched after cleavage or hybridization, which is associated with a strong fluorescence signal increase. Different strategies of fluorescence signal amplification ranging from large and small protease-sensing molecules to oligonucleotide-sensing and nanoparticle-based probes are presented in this chapter.
authors.affiliation: Department of Clinical Radiology, University of Münster, University Hospital, Münster, Germany. bremerc@uni-muenster.de
authors.forename: Christoph
authors.initials: C
authors.lastname: Bremer
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D015374:Biosensing Techniques; D004247:DNA / Q000378:metabolism; D003952:Diagnostic Imaging / Q000379:methods*; D031541:Fluorescence Resonance Energy Transfer; D005456:Fluorescent Dyes / Q000378:metabolism; D015870:Gene Expression; D006801:Humans; D008279:Magnetic Resonance Imaging; D015336:Molecular Probe Techniques; D015335:Molecular Probes / Q000378:metabolism*; D053758:Nanoparticles; D009841:Oligonucleotides / Q000378:metabolism; D055095:Optics and Photonics; D010447:Peptide Hydrolases / Q000378:metabolism; D012815:Signal Processing, Computer-Assisted
chemical_list: D015415:Biomarkers; D005456:Fluorescent Dyes; D015335:Molecular Probes; D009841:Oligonucleotides; D004247:DNA; D010447:Peptide Hydrolases