Photoacoustic (PA) imaging uses light excitation to generate the acoustic signal for detection and improves tissue penetration depth and spatial resolution in the clinically relevant depth of living subjects. However, strong background signals from blood and pigments have significantly compromised the sensitivity of PA imaging with exogenous contrast agents. Here we report a nanoparticle-based probe design that uses light to reversibly modulate the PA emission to enable photoacoustic photoswitching imaging (PAPSI) in living mice. Such a nanoprobe is built with upconverting nanocrystals and photoswitchable small molecules and can be switched on by NIR light through upconversion to UV energy. Reversibly photoswitching of the nanoprobe reliably removed strong tissue background, increased the contrast-to-noise ratio, and thus improved imaging sensitivity. We have shown that PAPSI can image 0.05 nM of the nanoprobe in hemoglobin solutions and 10 labeled cancer cells after implantation in living mice using a commercial PA imager.
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http://dx.doi.org/10.1002/anie.202116802 | DOI Listing |
Chem Sci
December 2024
Applied Chemistry Program, Graduate School of Advanced Science and Engineering, Hiroshima University 1-4-1 Kagamiyama Higashihiroshima 739-8527 Japan
Angew Chem Int Ed Engl
November 2024
Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford, OX1 3TA, UK.
Stimuli-responsive synthetic ionophores allow for spatial and temporal control over ion transport, with promise for applications in targeted therapy. Relay transporters have emerged as a new class of ion transporters - these are anchored carriers that sit in both leaflets of the bilayer and mediate transport across the membrane by passing ions between them. The relays are themselves membrane impermeable, and so must be incorporated into the membrane during vesicle preparation.
View Article and Find Full Text PDFJ Am Chem Soc
December 2024
Department of Chemistry and Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, United States.
Designing photoswitches that have large structural changes, are visible-light responsive, and are compatible with water is a major challenge for moving toward applications in biological systems. Despite the potential for Stenhouse salts to be a water-compatible counterpart to the popular DASA photoswitches, there has not yet been any major investigation into their properties as a photoswitch. Here, we report a series of aniline-based Stenhouse salt () photoswitches with electron donating and withdrawing groups.
View Article and Find Full Text PDFAdv Mater
November 2024
Friedrich-Alexander-Universität Erlangen-Nürnberg, Department of Chemistry and Pharmacy, Nikolaus-Fiebiger-Str. 10, 91058, Erlangen, Germany.
Molecular photoswitches produce light-controlled changes at the nanometer scale and can therefore be used to alter the states and behavior of materials in a truly bottom-up fashion. Here an escalating photonic complexity of material property control with light is shown using a recently developed aza-diarylethene in combination with hemiindigo (HI) photoswitches. First, aza-diarylethene can be used as a photoswitch in polystyrene (PS) to reversibly inscribe relief-type 3D structures into PS.
View Article and Find Full Text PDFNanoscale
December 2024
Soft Foundry Institute, College of Engineering, Seoul National University, Seoul, Republic of Korea.
Brookite exists as the metastable phase of titania and often mediates the transformation of anatase to rutile. The photocatalytic competence of brookite relative to polymorphs anatase and rutile has generally been considered structurally and energetically unfavourable for reasons that remain largely unknown and unchallenged. However, the process of phase transformation and performance related cooperativity among all three polymorphs has recently unlocked alternative directions for exploring brookite photovoltaics.
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