title: The Effects of Nonporous Silica Nanoparticles on Cultured Human Keratocytes.
abstract: Silica nanoparticles (SiNPs) are promising carriers for ophthalmic drug delivery. In this study, we investigated the effect of various sizes of nonporous SiNPs on cultured human keratocytes.
  
  
  
  Three different sizes of SiNPs (50, 100, and 150 nm) were manufactured. Primarily cultured human keratocytes were exposed to different concentrations (0, 25, 50, and 100 μg/mL) of three sizes of SiNPs for up to 72 hours. Intracellular reactive oxygen species (ROS) generation, cellular viability, lactate dehydrogenase (LDH) assay, autophagy, vimentin expression, and mammalian target of rapamycin (mTOR) pathway activation were evaluated. Intracellular distribution of SiNPs was evaluated with transmission electron microscopy.
  
  
  
  Transmission electron microscopy revealed SiNPs were taken up by keratocytes inside cytoplasmic vacuoles. Neither nuclear entry of SiNPs nor mitochondrial structural damage was observed. Both intracellular ROS generation and LDH level remained unchanged with up to 100 μg/mL SiNP treatment. Cellular viability was not affected by SiNP treatment. Autophagy showed significant dose-dependent activation with 50- and 100-nm SiNPs. However, mTOR activation remained unchanged. Vimentin expression did not show any significant increase with SiNPs.
  
  
  
  Our findings suggested that 50-, 100-, and 150-nm SiNPs did not induce significant cytotoxicity in cultured human keratocytes at concentrations up to 100 μg/mL.
authors.affiliation: Department of Ophthalmology, Dongguk University, Ilsan Hospital, Goyang, South Korea.
authors.forename: Bora
authors.initials: B
authors.lastname: Yim
authors.affiliation: Department of Ophthalmology, Dongguk University, Ilsan Hospital, Goyang, South Korea.
authors.forename: Joo-Hee
authors.initials: JH
authors.lastname: Park
authors.affiliation: School of Chemical Engineering and Materials Science, Chung-Ang University, Seoul, South Korea.
authors.forename: Hyejoong
authors.initials: H
authors.lastname: Jeong
authors.affiliation: School of Chemical Engineering and Materials Science, Chung-Ang University, Seoul, South Korea.
authors.forename: Jinkee
authors.initials: J
authors.lastname: Hong
authors.affiliation: Department of Ophthalmology, Hallym University College of Medicine, Seoul, South Korea.
authors.forename: Young-Joo
authors.initials: YJ
authors.lastname: Shin
authors.affiliation: Department of Ophthalmology and Visual Sciences, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York, United States.
authors.forename: Roy S
authors.initials: RS
authors.lastname: Chuck
authors.affiliation: Department of Ophthalmology, Dongguk University, Ilsan Hospital, Goyang, South Korea.
authors.forename: Choul Yong
authors.initials: CY
authors.lastname: Park
mesh_terms: D000818:Animals; D001343:Autophagy; D015153:Blotting, Western; D002452:Cell Count; D002470:Cell Survival; D002478:Cells, Cultured; D060527:Corneal Keratocytes / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D004195:Disease Models, Animal; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008297:Male; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles; D010316:Particle Size; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism; D012822:Silicon Dioxide / Q000494:pharmacology*
chemical_list: D017382:Reactive Oxygen Species; D012822:Silicon Dioxide; D007770:L-Lactate Dehydrogenase