University of Oulu

ACS Appl. Mater. Interfaces 2021, 13, 34, 40392–40400,

Comparison between fluorescence imaging and elemental analysis to determine biodistribution of inorganic nanoparticles with strong light absorption

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Author: Tamarov, Konstantin1; Wang, Julie Tzu-Wen2; Kari, Juuso1;
Organizations: 1Department of Applied Physics, Faculty of Science and Forestry, University of Eastern Finland, Kuopio 70211, Finland
2School of Cancer and Pharmaceutical Sciences, Faculty of Life Sciences & Medicine, King’s College London, London SE1 9NH, U.K.
3Research Unit of Sustainable Chemistry, University of Oulu, Oulu 90570, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 5.7 MB)
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Language: English
Published: American Chemical Society, 2021
Publish Date: 2021-11-08


Black porous silicon nanoparticles (BPSi NPs) are known as highly efficient infrared light absorbers that are well-suitable for photothermal therapy (PTT) and photoacoustic imaging (PAI). PTT and PAI require a sufficient number of effectively light-absorbing NPs to be accumulated in tumor after intravenous administration. Herein, biodistribution of PEGylated BPSi NPs with different sizes (i.e., 140, 200, and 300 nm in diameter) is investigated after intravenous administration in mice. BPSi NPs were conjugated with fluorescent dyes Cy5.5 and Cy7.5 to track them in vitro and in vivo, respectively. Optical imaging with an in vivo imaging system (IVIS) was found to be an inadequate technique to assess the biodistribution of the dye-labeled BPSi NPs in vivo because the intrinsic strong absorbance of the BPSi NPs interfered fluorescence detection. This challenge was resolved via the use of inductively coupled plasma optical emission spectrometry to analyze ex vivo the silicon content in different tissues and tumors. The results indicated that most of the polyethylene glycol-coated BPSi NPs were found to accumulate in the liver and spleen after intravenous injection. The smallest 140 nm particles accumulated the most in tumors at an amount of 9.5 ± 3.4% of the injected dose (concentration of 0.18 ± 0.08 mg/mL), the amount known to produce sufficient heat for cancer PTT. Furthermore, the findings from the present study also suggest that techniques other than optical imaging should be considered to study the organ biodistribution of NPs with strong light absorbance properties.

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Series: ACS applied materials & interfaces
ISSN: 1944-8244
ISSN-E: 1944-8252
ISSN-L: 1944-8244
Volume: 13
Issue: 34
Pages: 40392 - 40400
DOI: 10.1021/acsami.1c11875
Type of Publication: A1 Journal article – refereed
Field of Science: 116 Chemical sciences
114 Physical sciences
Funding: The work was financially supported by the Academy of Finland (Grant Nos. 314412, 314552, and 331371).
Copyright information: © 2021 The Authors. Published byAmerican Chemical Society. Published under a Creative Commons Attribution License.