title: Label-free photoacoustic nanoscopy.
abstract: Super-resolution microscopy techniques - capable of overcoming the diffraction limit of light - have opened new opportunities to explore subcellular structures and dynamics not resolvable in conventional far-field microscopy. However, relying on staining with exogenous fluorescent markers, these techniques can sometimes introduce undesired artifacts to the image, mainly due to large tagging agent sizes and insufficient or variable labeling densities. By contrast, the use of endogenous pigments allows imaging of the intrinsic structures of biological samples with unaltered molecular constituents. Here, we report label-free photoacoustic (PA) nanoscopy, which is exquisitely sensitive to optical absorption, with an 88 nm resolution. At each scanning position, multiple PA signals are successively excited with increasing laser pulse energy. Because of optical saturation or nonlinear thermal expansion, the PA amplitude depends on the nonlinear incident optical fluence. The high-order dependence, quantified by polynomial fitting, provides super-resolution imaging with optical sectioning. PA nanoscopy is capable of super-resolution imaging of either fluorescent or nonfluorescent molecules.
authors.affiliation: Washington University in St. Louis, Department of Biomedical Engineering, Optical Imaging Laboratory, One Brookings Drive, St. Louis, Missouri 63130, United States.
authors.forename: Amos
authors.initials: A
authors.lastname: Danielli
authors.affiliation: Washington University in St. Louis, Department of Biomedical Engineering, Optical Imaging Laboratory, One Brookings Drive, St. Louis, Missouri 63130, United States.
authors.forename: Konstantin
authors.initials: K
authors.lastname: Maslov
authors.affiliation: Washington University in St. Louis, Department of Biomedical Engineering, Optical Imaging Laboratory, One Brookings Drive, St. Louis, Missouri 63130, United States.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Garcia-Uribe
authors.affiliation: Washington University in St. Louis, Department of Biomedical Engineering, Optical Imaging Laboratory, One Brookings Drive, St. Louis, Missouri 63130, United States.
authors.forename: Amy M
authors.initials: AM
authors.lastname: Winkler
authors.affiliation: Washington University in St. Louis, Department of Biomedical Engineering, Optical Imaging Laboratory, One Brookings Drive, St. Louis, Missouri 63130, United States.
authors.forename: Chiye
authors.initials: C
authors.lastname: Li
authors.affiliation: Washington University in St. Louis, Department of Biomedical Engineering, Optical Imaging Laboratory, One Brookings Drive, St. Louis, Missouri 63130, United States.
authors.forename: Lidai
authors.initials: L
authors.lastname: Wang
authors.affiliation: Washington University in St. Louis, Department of Internal Medicine, Center for Pharmacogenomics, 660 S. Euclid, St. Louis, Missouri 63110, United States.
authors.forename: Yun
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Washington University in St. Louis, Department of Internal Medicine, Center for Pharmacogenomics, 660 S. Euclid, St. Louis, Missouri 63110, United States.
authors.forename: Gerald W
authors.initials: GW
authors.lastname: Dorn
authors.affiliation: Washington University in St. Louis, Department of Biomedical Engineering, Optical Imaging Laboratory, One Brookings Drive, St. Louis, Missouri 63130, United States.
authors.forename: Lihong V
authors.initials: LV
authors.lastname: Wang
mesh_terms: D000818:Animals; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005347:Fibroblasts / Q000648:ultrastructure*; D007089:Image Enhancement / Q000295:instrumentation; D007834:Lasers; D008546:Melanoma, Experimental; D051379:Mice; D008853:Microscopy / Q000295:instrumentation*; D057054:Molecular Imaging / Q000295:instrumentation*; D041681:NIH 3T3 Cells; D036103:Nanotechnology / Q000295:instrumentation*; D061088:Photoacoustic Techniques / Q000295:instrumentation*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013194:Staining and Labeling; D013347:Subcellular Fractions / Q000648:ultrastructure*
references.citation: J Biophotonics. 2013 Jun;6(6-7):543-8
references.pmid: 23184422
references.citation: Nano Lett. 2010 Oct 13;10(10):4249-52
references.pmid: 20831171
references.citation: Phys Rev Lett. 2001 Apr 16;86(16):3550-3
references.pmid: 11328020
references.citation: Science. 2012 Mar 23;335(6075):1458-62
references.pmid: 22442475
references.citation: J Biophotonics. 2010 Dec;3(12):791-806
references.pmid: 20572284
references.citation: Science. 1990 Apr 6;248(4951):73-6
references.pmid: 2321027
references.citation: Proc Natl Acad Sci U S A. 2005 Sep 13;102(37):13081-6
references.pmid: 16141335
references.citation: Opt Lett. 2011 Apr 1;36(7):1236-8
references.pmid: 21479041
references.citation: Phys Rev Lett. 2014 Jan 10;112(1):014302
references.pmid: 24483902
references.citation: J Biomed Opt. 2012 Aug;17(8):080505-1
references.pmid: 23224156
references.citation: Annu Rev Biochem. 2009;78:993-1016
references.pmid: 19489737
references.citation: Lasers Surg Med. 2005 Jan;36(1):22-30
references.pmid: 15662629
references.citation: Appl Phys Lett. 2010 Oct 18;97(16):163701
references.pmid: 21079726
references.citation: Langmuir. 2009 May 5;25(9):5076-83
references.pmid: 19275191
references.citation: Nat Photonics. 2011 Feb;5(2):110-116
references.pmid: 25558274
references.citation: Opt Lett. 2011 Mar 1;36(5):769-71
references.pmid: 21368977
references.citation: J Cell Biol. 2003 Jan 20;160(2):189-200
references.pmid: 12527753
references.citation: Opt Lett. 1994 Jun 1;19(11):780-2
references.pmid: 19844443
references.citation: Proc Natl Acad Sci U S A. 2009 Dec 29;106(52):22287-92
references.pmid: 20018714
references.citation: Biophys J. 2011 Oct 5;101(7):1651-60
references.pmid: 21961591
references.citation: J Biomed Opt. 2013 Feb;18(2):20504
references.pmid: 23370407
references.citation: Annu Rev Anal Chem (Palo Alto Calif). 2008;1:883-909
references.pmid: 20636101
references.citation: Biophys J. 2012 Feb 8;102(3):672-81
references.pmid: 22325291
references.citation: Nat Photonics. 2009 Aug 29;3(9):503-509
references.pmid: 20161535
references.citation: Opt Lett. 2011 Apr 1;36(7):1137-9
references.pmid: 21479008
references.citation: Science. 2006 Sep 15;313(5793):1642-5
references.pmid: 16902090
references.citation: Nat Methods. 2006 Oct;3(10):793-5
references.pmid: 16896339
references.citation: Small. 2014 Jan 15;10(1):135-42
references.pmid: 23864531