Biodegradable magnetic-fluorescent magnetite/poly(dl-lactic acid-co-alpha,beta-malic acid) composite nanoparticles for stem cell labeling.
Bifunctional superparamagnetic magnetite/poly(dl-lactic acid-co-alpha,beta-malic acid) composite nanoparticles (PLMA-MNPs) detectable by both magnetic resonance imaging (MRI) and fluorescence microscopy were synthesized by coating Fe(3)O(4) nanoparticles with biodegradable poly(dl-lactic acid-co-alpha,beta-malic acid) copolymer (PLMA) with covalently bound fluorescein isothiocyanate (FITC). The FITC modified PLMA-MNPs (FITC-PLMA-MNPs) have a hydrodynamic diameter of 100nm and an anionic surface. MTT assays of mouse macrophages, 3T3 fibroblasts and human mesenchymal stem cells (hMSCs) incubated with these nanoparticles indicated that these nanoparticles did not possess significant cytotoxicity. Furthermore, the osteogenic and adipogenic differentiations of the hMSCs were not influenced by the labeling process. As a result of the high R(2) (164.8mm(-1)s(-1)) and R(2)/R(1) ratio (32) of the FITC-PLMA-MNPs, the labeled hMSCs can be detected by a clinical 3T MRI scanner at an in vitro detection threshold of about 1200 cells. The green fluorescence associated with the FITC can be readily observed. Such nanoparticles can potentially be used as a T(2)-weighted contrast agent and fluorescent agent for stem cell labeling.
Department of Diagnostic Radiology, National University of Singapore, Kent Ridge, Singapore 119260, Singapore.
Liang
L
Wang
Koon-Gee
KG
Neoh
En-Tang
ET
Kang
Borys
B
Shuter
Shih-Chang
SC
Wang
D000818:Animals; D002454:Cell Differentiation; D002478:Cells, Cultured; D005456:Fluorescent Dyes / Q000737:chemistry*; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008280:Magnetics; D051379:Mice; D018613:Microscopy, Confocal; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles; D011091:Polyesters / Q000378:metabolism*; D017550:Spectroscopy, Fourier Transform Infrared; D013234:Stem Cells / Q000166:cytology*
D005456:Fluorescent Dyes; D011091:Polyesters; C551150:poly(lactic acid-co-malic acid)