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Acicular, but not globular, titanium dioxide nanoparticles stimulate keratinocytes to produce pro‐inflammatory cytokines
Author(s) -
Hiroike Mizuho,
Sakabe Junichi,
Kobayashi Miwa,
Shimauchi Takatoshi,
Ito Taisuke,
Hirakawa Satoshi,
Inoh Akinori,
Tokura Yoshiki
Publication year - 2013
Publication title -
the journal of dermatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 65
eISSN - 1346-8138
pISSN - 0385-2407
DOI - 10.1111/1346-8138.12132
Subject(s) - acicular , cytokine , titanium dioxide , particle size , nanoparticle , biophysics , tumor necrosis factor alpha , interleukin , materials science , scanning electron microscope , chemistry , nanotechnology , microbiology and biotechnology , chemical engineering , medicine , biology , metallurgy , composite material , microstructure , engineering
Abstract Titanium dioxide ( T i O 2 ) nanoparticles, widely used for daily products, are believed to be biologically inert, but they may cause adverse effects on cells, presumably depending on the particle size and shape. One of the critical targets of T i O 2 particles is epidermal keratinocytes, and their initial response to T i O 2 may be production of pro‐inflammatory cytokines. We therefore investigated the effects of four types of T i O 2 particles on cytokine expression/production by real‐time reverse transcription polymerase chain reaction and enzyme‐linked immunoassay. The T i O 2 particles included three acicular types, FTL ‐100 (length, 1.68 μm; diameter, 130 nm), FTL ‐200 (2.86, 210) and FTL ‐300 (5.15, 270), and one globular type, PT ‐301 (diameter, 270 nm). Normal human epidermal keratinocytes ( NHEK ) were cultured with each of the T i O 2 particles. During cultivation, the acicular forms of T i O 2 were seen by scanning electron microscopy to be internalized by NHEK . The three acicular particles increased the m RNA expressions and supernatant productions of interleukin ( IL )‐1α, IL ‐1β, IL ‐6, tumor necrosis factor‐α and IL ‐8 in particle number‐dependent manners, whereas globular PT ‐301 had very weak activity. Thus, T i O 2 particles may induce skin inflammation depending on the size and shape, providing knowledge on their health usage.