Organic Semiconducting Agents for Deep‐Tissue Molecular Imaging: Second Near‐Infrared Fluorescence, Self‐Luminescence, and Photoacoustics

Advanced Materials, Journal Year: 2018, Volume and Issue: 30(49)

Published: July 29, 2018

Optical imaging has played a pivotal role in biology and medicine, but it faces challenges of relatively low tissue penetration poor signal-to-background ratio due to light scattering autofluorescence. To overcome these issues, second near-infrared fluorescence, self-luminescence, photoacoustic have recently emerged, which utilize an optical region with reduced light-tissue interactions, eliminate real-time excitation, detect acoustic signals negligible attenuation, respectively. Because there are only few endogenous molecules absorbing or emitting above the visible region, development contrast agents is essential for those deep-tissue modalities. Organic semiconducting π-conjugated frameworks can be synthesized meet different requirements their easy chemical modification legible structure-property relation. Herein, applications organic including small-molecule nanoparticle derivatives summarized. In particular, molecular engineering nanoformulation approaches further improve detection sensitivity modalities highlighted. Finally, current potential opportunities this emerging subfield biomedical discussed.

Language: Английский

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Boosting the down-shifting luminescence of rare-earth nanocrystals for biological imaging beyond 1500 nm

Nature Communications, Journal Year: 2017, Volume and Issue: 8(1)

Published: Sept. 25, 2017

Abstract In vivo fluorescence imaging in the near-infrared region between 1500–1700 nm (NIR-IIb window) affords high spatial resolution, deep-tissue penetration, and diminished auto-fluorescence due to suppressed scattering of long-wavelength photons large fluorophore Stokes shifts. However, very few NIR-IIb fluorescent probes exist currently. Here, we report synthesis a down-conversion luminescent rare-earth nanocrystal with cerium doping (Er/Ce co-doped NaYbF 4 core an inert NaYF shell). Ce is found suppress up-conversion pathway while boosting by ~9-fold produce bright 1550 luminescence under 980 excitation. Optimization shell coating surrounding hydrophilic surface functionalization minimize quenching effect water. The resulting biocompatible, emitting nanoparticles enable fast blood vasculature mouse brain hindlimb window short exposure time 20 ms for based probes.

Language: Английский

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Direct Evidence for Coupled Surface and Concentration Quenching Dynamics in Lanthanide-Doped Nanocrystals

Journal of the American Chemical Society, Journal Year: 2017, Volume and Issue: 139(8), P. 3275 - 3282

Published: Feb. 7, 2017

Luminescence quenching at high dopant concentrations generally limits the concentration to less than 1–5 mol% in lanthanide-doped materials, and this remains a major obstacle designing materials with enhanced efficiency/brightness. In work, we provide direct evidence that process is energy migration surface (i.e., quenching) as opposed common misconception of cross-relaxation between ions. We show after an inert epitaxial shell growth, erbium (Er3+) 100 NaY(Er)F4/NaLuF4 core/shell nanocrystals enhance emission intensity both upconversion downshifted luminescence across different excitation wavelengths (980, 800, 658 nm), negligible effects. Our results highlight strong coupling effects colloidal nanocrystals, growth can overcome quenching. These fundamental insights into photophysical processes heavily doped will give rise properties not previously thought possible compositions optimized bulk.

Language: Английский

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Recent advances in near-infrared II fluorophores for multifunctional biomedical imaging

Chemical Science, Journal Year: 2018, Volume and Issue: 9(19), P. 4370 - 4380

Published: Jan. 1, 2018

In recent years, owing to unsatisfactory clinical imaging clarity and depths in the living body for early diagnosis prognosis, novel modalities with high bioimaging performance have been actively explored. The remarkable headway made second near-infrared region (NIR-II, 1000-1700 nm) has promoted development of biomedical significantly. NIR-II fluorescence possesses a number merits which prevail over traditional NIR-I (400-900 fundamental research, such as reduced photon scattering, well auto-fluorescence improved penetration depth. Functional probes instant precise feedback vivo information are at core this modality superb imaging. Herein, we review recently developed fluorophores including carbon nanotubes, organic small molecules, quantum dots, conjugated polymers rare-earth-doped materials present superior multifunctionality regions (1000-1700 nm).

Language: Английский

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Nanocarbons for Biology and Medicine: Sensing, Imaging, and Drug Delivery

Chemical Reviews, Journal Year: 2019, Volume and Issue: 119(16), P. 9559 - 9656

Published: July 9, 2019

Nanocarbons with different dimensions (e.g., 0D fullerenes and carbon nanodots, 1D nanotubes graphene nanoribbons, 2D oxides, 3D nanodiamonds) have attracted enormous interest for applications ranging from electronics, optoelectronics, photovoltaics to sensing, bioimaging, therapeutics due their unique physical chemical properties. Among them, nanocarbon-based theranostics (i.e., diagnostics) is one of the most intensively studied applications, as these nanocarbon materials serve excellent biosensors, versatile drug/gene carriers specific targeting in vivo, effective photothermal nanoagents cancer therapy, promising fluorescent nanolabels cell tissue imaging. This review provides a systematic overview latest theranostic comprehensive comparison characteristics influences on applications. We first introduce allotropes that can be used respective preparation surface functionalization approaches well Theranostic are described separately both vitro vivo systems by highlighting protocols biosystems, followed toxicity biodegradability implications. Finally, this outlines design considerations key unifying themes will foundational principle researchers study, investigate, generate effective, biocompatible, nontoxic materials-based models we summarize an outlook challenges novel using hard-to-treat cancers other diseases. intends present guideline nanotechnology biomedicine selection strategy according requirements.

Language: Английский

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