Eco-friendly synthesis of fluorescent cobalt-doped manganese ferrites for thermo-therapeutic applications

abstract

The synthesis of high -quality nanoparticles for biomedical applications through environmentally friendly methods is a major challenging task. In this work, oxidative precipitation and a novel method, oxidative hydrothermal synthesis, are explored as one -pot eco-friendly synthesis routes to obtain single phase multicore-like and single -core citrate -stabilized cobalt and/or manganese -doped ferrite (CoxMn (1-x) Fe2O4, 0 < x < 1) nanoparticles, respectively. The Co2+ /Mn2+ ratio and synthesis method were found to influence the nanoparticles ' morphology and structure, with oxidative precipitation producing multicore-like structures and hydrothermal synthesis yielding single -core particles with crystalline sizes in the range of 2 - 10 nm and 4 - 11 nm, respectively. Inductively coupled plasma optical emission spectrometry (ICP-OES) indicated a composition near the expected values. Mixed ferrites displayed improved saturation magnetization up to 60 A.m(2) /kg, exhibiting superparamagnetism at room temperature. The particles ' stability was evaluated in physiological pH, and the mixed ferrites displayed intrinsic fluorescence emission in the violet -green range with a maximum wavelength near 425 nm. The cobalt and/or manganese -doped ferrites were evaluated for magnetic hyperthermia and photothermia, displaying high heating efficiency for several alternating magnetic field conditions (up to -2.5 nHm(2) /kg) compatible with biological applications, and high light -to -heat conversion efficiency (up to -53%) with near infrared (NIR) laser irradiation at 808 nm. Hereby, the oxidative precipitation and oxidative hydrothermal synthesis are promising eco-friendly methods for the development of crystalline citrate -stabilized cobalt and/or manganese -doped ferrites with multicore-like and single -core spherical morphology, respectively, without requiring additional post -synthesis treatments and with suitable properties for biomedical applications, such as magnetic hyperthermia, photothermia and as prospective fluorescent probes for bio-imaging.

keywords

IRON-OXIDE NANOPARTICLES; MAGNETIC-PROPERTIES; HYDROTHERMAL SYNTHESIS; FE3O4 NANOPARTICLES; CATION DISTRIBUTION; HYPERTHERMIA; TEMPERATURE; ANISOTROPY; NANOCRYSTALS; SPECTROSCOPY

subject category

Materials Science

authors

Veloso, SRS; Nereu, SF; Amorim, CO; Amaral, VS; Correa-Duarte, MA; Castanheira, EMS

Groups

G2 - Photonic, Electronic and Magnetic Materials
G6 - Virtual Materials and Artificial Intelligence

Projects

CICECO - Aveiro Institute of Materials (UIDB/50011/2020)

CICECO - Aveiro Institute of Materials (UIDP/50011/2020)

Associated Laboratory CICECO-Aveiro Institute of Materials (LA/P/0006/2020)

acknowledgements

This work was funded by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding of CF-UM-UP (UIDB/04650/2020, UIDP/04650/2020) , CICECO Aveiro Institute of Materials (UIDB/50011/2020, UIDP/50011/2020 and LA/P/0006/2020) , Associate Laboratory Institute of Nanostructures, Nanomodelling and Nanofabrication-i3N (LISBOA-01 -0247-FEDER-039985/POCI-01 -0247-FEDER-039985, LA/P/0037/2020, UIDP/50025/2020, and UIDB/50025/2020) , and by the Ministerio de Economia y Competitividad de Espana (PID2020 -113704RB-I00 and PID2020 -119242RB-I00) , Xunta de Galicia (Centro Singular de Investigacion de Galicia-Accreditation 2019 -2022 ED431G 2019/06 and IN607A 2018/5 and project ED431C 2020 -06) , the European Union (EU-ERDF Interreg V-A -Spain-Portugal 0245_IBEROS_1_E, 0712_ACUINANO_1_E, 0624_2IQBIONEURO_6E, and Interreg Atlantic Area NANOCULTURE 1.102.531) , and the European Union H2020-MSCA-RISE-2019 PEPSA-MATE project. S.R.S. Veloso acknowledges FCT for a PhD grant (SFRH/BD/144017/2019) . Support from MAP-Fis Doctoral Programme is also acknowledged.