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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Vacancy-Induced Visible Light-Driven Fluorescence in Toxic Ion-Free Resorbable Magnetic Calcium Phosphates for Cell Imaging Applications

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Srinivasan, Baskar [1] ; Kolanthai, Elayaraja [2, 3] ; Kumaraswamy, Nivethaa Eluppai Asthagiri [1] ; Pugazhendhi, Abinaya Sindu [2] ; Catalani, Luiz Henrique [2] ; Subbaraya, Narayana Kalkura [1]
Total Authors: 6
[1] Anna Univ, Crystal Growth Ctr, Chennai 600025, Tamil Nadu - India
[2] Univ Sao Paulo, Dept Quim Fundamental, Inst Quim, BR-05508000 Sao Paulo - Brazil
[3] Univ Cent Florida, Dept Mat Sci & Engn, Adv Mat Proc & Anal Ctr, Orlando, FL 32816 - USA
Total Affiliations: 3
Document type: Journal article
Source: ACS APPLIED BIO MATERIALS; v. 4, n. 4, p. 3256-3263, APR 19 2021.
Web of Science Citations: 0

Multifunctional nanosized particles are very beneficial in the field of biomedicine. Bioactive and highly biocompatible calcium phosphate (CaP) nanoparticles (similar to 50 nm) exhibiting both superparamagnetic and fluorescence properties were synthesized by incorporating dual ions (Fe3+ and Sr2+) in HAp (hydroxyapatite) {[}Ca-10(PO4)(6)(OH)(2)]. Insertion of Fe3+ creates oxygen vacancies at the PO43- site, thereby destabilizing the structure. Thus, in order to maintain the structural stability, Sr2+ has been incorporated. This incorporation of Sr2+ leads to an intense emission at 550 nm. HAp nanoparticles when subjected to thermal treatment (800 degrees C) transform to beta-TCP, exhibiting emission at 710 nm due to the emergence of an intermediate band. Moreover, these nanoparticles exhibit fluorescence in visible light when compared to the other UV and IR fluorescence excitation sources which could damage the tissues. The synthesis involving the combination of ultrasound and microwave techniques resulted in the distribution of Fe3+ in the interstitial sites of CaP, which is responsible for the excellent fluorescent properties. Moreover, thermally treated CaP becomes superparamagnetic, without affecting the desired optical properties. The bioactive, biocompatible, magnetic, and fluorescent properties of this resorbable CaP which is free from toxic heavy metals (Eu, Gd, etc.) could help in overcoming the long-term cytotoxicity. This could also be useful in tracking the location of the nanoparticles during drug delivery and magnetic hyperthermia. The bioactive fluorescent CaP nanoparticle helps in monitoring the bone growth and in addition, it could be employed in cell imaging applications. The in vitro MCF-7 imaging using the nanoparticles after 24 h of uptake at 465 nm evidences the bioimaging capability of the prepared nanoparticles. The reproducibility of the defect level is essential for the defect-induced emission properties. The synthesis of nontoxic fluorescent CaP is highly reproducible with the present synthesis method. Hence, it could be safely employed in various biomedical applications. (AU)

FAPESP's process: 15/19694-8 - Bioactivity of multi-layer membranes loaded with various protein markers for tissue engineering applications
Grantee:Elayaraja Kolanthai
Support type: Scholarships in Brazil - Post-Doctorate
FAPESP's process: 11/21442-6 - Synthetic and natural polymers applied to tissue engineering
Grantee:Luiz Henrique Catalani
Support type: Research Projects - Thematic Grants