OBJECTIVE: For tissue engineering, there is a need for quantitative methods to map cell density inside three-dimensional (3-D) bioreactors to assess tissue growth over time. The current cell mapping methods in 2-D cultures are based on optical microscopy. However, optical methods fail in 3-D due to increased opacity of the tissue. We present an approach for measuring the density of cells embedded in a hydrogel to generate quantitative maps of cell density in a living, 3-D tissue culture sample. METHODS: Quantification of cell density was obtained by calibrating the 1H T2, magnetization transfer (MT) and diffusion-weighted nuclear magnetic resonance (NMR) signals to samples of known cell density. Maps of cell density were generated by weighting NMR images by these parameters post-calibration. RESULTS: The highest sensitivity weighting arose from MT experiments, which yielded a limit of detection (LOD) of [Formula: see text] cells/mL/ √{Hz} in a 400 MHz (9.4 T) magnet. CONCLUSION: This mapping technique provides a noninvasive means of visualizing cell growth within optically opaque bioreactors. SIGNIFICANCE: We anticipate that such readouts of tissue culture growth will provide valuable feedback for controlled cell growth in bioreactors.
OBJECTIVE: For tissue engineering, there is a need for quantitative methods to map cell density inside three-dimensional (3-D) bioreactors to assess tissue growth over time. The current cell mapping methods in 2-D cultures are based on optical microscopy. However, optical methods fail in 3-D due to increased opacity of the tissue. We present an approach for measuring the density of cells embedded in a hydrogel to generate quantitative maps of cell density in a living, 3-D tissue culture sample. METHODS: Quantification of cell density was obtained by calibrating the 1H T2, magnetization transfer (MT) and diffusion-weighted nuclear magnetic resonance (NMR) signals to samples of known cell density. Maps of cell density were generated by weighting NMR images by these parameters post-calibration. RESULTS: The highest sensitivity weighting arose from MT experiments, which yielded a limit of detection (LOD) of [Formula: see text] cells/mL/ √{Hz} in a 400 MHz (9.4 T) magnet. CONCLUSION: This mapping technique provides a noninvasive means of visualizing cell growth within optically opaque bioreactors. SIGNIFICANCE: We anticipate that such readouts of tissue culture growth will provide valuable feedback for controlled cell growth in bioreactors.
Authors: T Sugahara; Y Korogi; M Kochi; I Ikushima; Y Shigematu; T Hirai; T Okuda; L Liang; Y Ge; Y Komohara; Y Ushio; M Takahashi Journal: J Magn Reson Imaging Date: 1999-01 Impact factor: 4.813
Authors: M E Bernardino; W Small; J Goldstein; C W Sewell; P J Sones; K Gedgaudas-McClees; J T Galambos; J Wenger; W J Casarella Journal: AJR Am J Roentgenol Date: 1983-12 Impact factor: 3.959
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Authors: G Manenti; M Di Roma; S Mancino; D A Bartolucci; G Palmieri; R Mastrangeli; R Miano; E Squillaci; G Simonetti Journal: Radiol Med Date: 2008-04-02 Impact factor: 3.469