ROS enhancement by silicon nanoparticles in X-ray irradiated aqueous suspensions and in glioma C6 cells

P.M.D. GARA; N.I. GARABANO; M.J. LLANSOLA PORTOLES; M.S. MORENO; D. DODAT; O.R. CASAS; M.C. GONZALEZ ; M.L. KOTLER

JOURNAL OF NANOPARTICLE RESEARCH

SPRINGER

Lugar: Berlin; Año: 2012 vol. 14 p. 741 - 753

1388-0764

The capability of silicon nanoparticles toincrease the yield of reactive species upon 4 MeVX-ray irradiation of aqueous suspensions and C6glioma cell cultures was investigated. ROS generationwas detected and quantified using several specificprobes. The particles were characterized by FTIR,XPS, TEM, DLS, luminescence, and adsorption spectroscopybefore and after irradiation to evaluate theeffect of high energy radiation on their structure. Thetotal concentration of O2•-/HO2•, HO • , and H2O2generated upon 4-MeV X-ray irradiation of 6.4 lMsilicon nanoparticle aqueous suspensions were on theorder of 10 lM per Gy, ten times higher than thatobtained in similar experiments but in the absence ofparticles. Cytotoxic 1O2 was generated only in irradiationexperiments containing the particles. The particlesurface became oxidized to SiO2 and the luminescenceyield reduced with the irradiation dose. Changes in thesurface morphology did not affect, within the experimentalerror, the yields ofROSgenerated per Gy. X-rayirradiation of glioma C6 cell cultures with incorporatedsilicon nanoparticles showed a marked production ofROS proportional to the radiation dose received. In theabsence of nanoparticles, the cells showed no irradiation-enhanced ROS generation. The obtained resultsindicate that silicon nanoparticles of\5 nm size havethe potential to be used as radiosensitizers for improvingthe outcomes of cancer radiotherapy. Their capabilityof producing 1O2 upon X-ray irradiation opensnovel approaches in the design of therapy strategies.