Penetration of silver nanoparticles into porcine skin ex vivo using fluorescence lifetime imaging microscopy, Raman microscopy, and surface-enhanced Raman scattering microscopy.
In order to investigate the penetration depth of silver nanoparticles (Ag NPs) inside the skin, porcine ears treated with Ag NPs are measured by two-photon tomography with a fluorescence lifetime imaging microscopy (TPT-FLIM) technique, confocal Raman microscopy (CRM), and surface-enhanced Raman scattering (SERS) microscopy. Ag NPs are coated with poly-N-vinylpyrrolidone and dispersed in pure water solutions. After the application of Ag NPs, porcine ears are stored in the incubator for 24 h at a temperature of 37°C. The TPT-FLIM measurement results show a dramatic decrease of the Ag NPs' signal intensity from the skin surface to a depth of 4 μm. Below 4 μm, the Ag NPs' signal continues to decline, having completely disappeared at 12 to 14 μm depth. CRM shows that the penetration depth of Ag NPs is 11.1 ± 2.1 μm. The penetration depth measured with a highly sensitive SERS microscopy reaches 15.6 ± 8.3 μm. Several results obtained with SERS show that the penetration depth of Ag NPs can exceed the stratum corneum (SC) thickness, which can be explained by both penetration of trace amounts of Ag NPs through the SC barrier and by the measurements inside the hair follicle, which cannot be excluded in the experiment.
Charité-Universitätsmedizin Berlin, Center of Experimental and Applied Cutaneous Physiology, Department of Dermatology, Venerology and Allergology, Charitéplatz 1, Berlin 10117, GermanybZhejiang University of Science and Technology, Department of Mechanic.
Yongjian
Y
Zhu
Charité-Universitätsmedizin Berlin, Center of Experimental and Applied Cutaneous Physiology, Department of Dermatology, Venerology and Allergology, Charitéplatz 1, Berlin 10117, GermanycKim Il Sung University, Department of Physics, Ryongnam-Dong, Taesong.
Chun-Sik
CS
Choe
Charité-Universitätsmedizin Berlin, Center of Experimental and Applied Cutaneous Physiology, Department of Dermatology, Venerology and Allergology, Charitéplatz 1, Berlin 10117, Germany.
Sebastian
S
Ahlberg
Charité-Universitätsmedizin Berlin, Center of Experimental and Applied Cutaneous Physiology, Department of Dermatology, Venerology and Allergology, Charitéplatz 1, Berlin 10117, Germany.
Martina C
MC
Meinke
Freie Universität Berlin, Department of Physics, Arnimallee 14, 14195 Berlin, Germany.
Ulrike
U
Alexiev
Charité-Universitätsmedizin Berlin, Center of Experimental and Applied Cutaneous Physiology, Department of Dermatology, Venerology and Allergology, Charitéplatz 1, Berlin 10117, Germany.
Juergen
J
Lademann
Charité-Universitätsmedizin Berlin, Center of Experimental and Applied Cutaneous Physiology, Department of Dermatology, Venerology and Allergology, Charitéplatz 1, Berlin 10117, Germany.
Maxim E
ME
Darvin
D000818:Animals; D003952:Diagnostic Imaging; D053768:Metal Nanoparticles / Q000737:chemistry*; D008853:Microscopy / Q000379:methods*; D018613:Microscopy, Confocal / Q000379:methods; D008856:Microscopy, Fluorescence / Q000379:methods*; D036103:Nanotechnology / Q000379:methods; D017785:Photons; D012834:Silver / Q000737:chemistry* / Q000493:pharmacokinetics; D012867:Skin / Q000473:pathology; D012869:Skin Absorption; D013059:Spectrum Analysis, Raman; D013499:Surface Properties; D013552:Swine
D012834:Silver