title: Optical clearing at cellular level.
abstract: Strong light scattering in tissues and blood reduces the usability of many optical techniques. By reducing scattering, optical clearing enables deeper light penetration and improves resolution in several optical imaging applications. We demonstrate the usage of optical tweezers and elastic light scattering to study optical clearing [one of the major mechanisms-matching of refractive indices (RIs)] at the single particle and cell level. We used polystyrene spheres and human red blood cells (RBCs) as samples and glycerol or glucose water solutions as clearing agents. Optical tweezers kept single microspheres and RBCs in place during the measurement of light scattering patterns. The results show that optical clearing reduces the scattering cross section and increases g. Glucose also decreased light scattering from a RBC. Optical clearing affected the anisotropy factor g of 23.25-μm polystyrene spheres, increasing it by 0.5% for an RI change of 2.2% (20% glycerol) and 0.3% for an RI change of 1.1% (13% glucose).
authors.affiliation: University of Oulu, Optoelectronics and Measurement Techniques Laboratory, P.O. Box 4500, Oulu 90014, Finland.
authors.forename: Matti
authors.initials: M
authors.lastname: Kinnunen
authors.affiliation: University of Oulu, Optoelectronics and Measurement Techniques Laboratory, P.O. Box 4500, Oulu 90014, Finland.
authors.forename: Alexander V
authors.initials: AV
authors.lastname: Bykov
authors.affiliation: University of Oulu, Optoelectronics and Measurement Techniques Laboratory, P.O. Box 4500, Oulu 90014, Finland.
authors.forename: Juho
authors.initials: J
authors.lastname: Tuorila
authors.affiliation: University of Oulu, Optoelectronics and Measurement Techniques Laboratory, P.O. Box 4500, Oulu 90014, Finland.
authors.forename: Tomi
authors.initials: T
authors.lastname: Haapalainen
authors.affiliation: National Yang-Ming University, Biophotonics and Molecular Imaging Research Center, Taipei 11221, Taiwan.
authors.forename: Artashes V
authors.initials: AV
authors.lastname: Karmenyan
authors.affiliation: University of Oulu, Optoelectronics and Measurement Techniques Laboratory, P.O. Box 4500, Oulu 90014, FinlandcSaratov State University, Research-Educational Institute of Optics and Biophotonics, Saratov 410012, RussiadInstitute of Precise Mechanics and Co.
authors.forename: Valery V
authors.initials: VV
authors.lastname: Tuchin
mesh_terms: D016880:Anisotropy; D004548:Elasticity; D004912:Erythrocytes / Q000473:pathology; D005947:Glucose / Q000737:chemistry; D005990:Glycerol / Q000737:chemistry; D006801:Humans; D007834:Lasers; D008027:Light; D008853:Microscopy / Q000379:methods; D008863:Microspheres; D061848:Optical Imaging; D052898:Optical Tweezers; D055095:Optics and Photonics; D011137:Polystyrenes / Q000737:chemistry; D012542:Scattering, Radiation; D041623:Tomography, Optical Coherence / Q000379:methods; D014867:Water / Q000737:chemistry
chemical_list: D011137:Polystyrenes; D014867:Water; D005947:Glucose; D005990:Glycerol