D.Plouffea, Brian; K.Nagesha, Dattatri; S.DiPietro, Robert; Sridhar, Srinvas; Heimand, Don; K.Murthya, Shashi; H.Lewisa, Lewis
Thermomagnetic determination of Fe3O4 magnetic nanoparticle diameters for biomedical applications Journal Article
In: Journal of Magnetism and Magnetic Materials, vol. 323, no. 17, pp. 2310-2317, 2011.
@article{H.Lewisa2011,
title = {Thermomagnetic determination of Fe3O4 magnetic nanoparticle diameters for biomedical applications},
author = {Brian D.Plouffea and Dattatri K.Nagesha and Robert S.DiPietro and Srinvas Sridhar and Don Heimand and Shashi K.Murthya and Lewis H.Lewisa
},
doi = {S0304885311002423},
year = {2011},
date = {2011-09-01},
journal = {Journal of Magnetism and Magnetic Materials},
volume = {323},
number = {17},
pages = {2310-2317},
abstract = {The utility and promise of magnetic nanoparticles (MagNPs) for biomedicine rely heavily on accurate determination of the particle diameter attributes. While the average functional size and size distribution of the magnetic nanoparticles directly impact the implementation and optimization of nanobiotechnology applications in which they are employed, the determination of these attributes using electron microscopy techniques can be time-consuming and misrepresentative of the full nanoparticle population. In this work the average particle diameter and distribution of an ensemble of Fe3O4 ferrimagnetic nanoparticles are determined solely from temperature-dependent magnetization measurements; the results compare favorably to those obtained from extensive electron microscopy observations. The attributes of a population of biocompatible Fe3O4 nanoparticles synthesized by a thermal decomposition method are obtained from quantitative evaluation of a model that incorporates the distribution of superparamagnetic blocking temperatures represented through thermomagnetization data. The average size and size distributions are determined from magnetization data via temperature-dependent zero-field-cooled magnetization. The current work is unique from existing approaches based on magnetic measurement for the characterization of a nanoparticle ensemble as it provides both the average particle size as well as the particle size distribution.
},
keywords = {featured, Nanomedicine},
pubstate = {published},
tppubtype = {article}
}
The utility and promise of magnetic nanoparticles (MagNPs) for biomedicine rely heavily on accurate determination of the particle diameter attributes. While the average functional size and size distribution of the magnetic nanoparticles directly impact the implementation and optimization of nanobiotechnology applications in which they are employed, the determination of these attributes using electron microscopy techniques can be time-consuming and misrepresentative of the full nanoparticle population. In this work the average particle diameter and distribution of an ensemble of Fe3O4 ferrimagnetic nanoparticles are determined solely from temperature-dependent magnetization measurements; the results compare favorably to those obtained from extensive electron microscopy observations. The attributes of a population of biocompatible Fe3O4 nanoparticles synthesized by a thermal decomposition method are obtained from quantitative evaluation of a model that incorporates the distribution of superparamagnetic blocking temperatures represented through thermomagnetization data. The average size and size distributions are determined from magnetization data via temperature-dependent zero-field-cooled magnetization. The current work is unique from existing approaches based on magnetic measurement for the characterization of a nanoparticle ensemble as it provides both the average particle size as well as the particle size distribution.
Makrigiorgos, Robert A. Cormack; Paul L. Nguyen; Anthony V. D'Amico; Sri Sridhar; Mike
Optimal drug release schedule for in-situ radiosensitization of image guided permanent prostate implants Journal Article
In: Proceedings Volume 7964, Medical Imaging 2011: Visualization, Image-Guided Procedures, and Modeling, vol. 7964, no. 2011, 2011.
@article{Makrigiorgos2011,
title = {Optimal drug release schedule for in-situ radiosensitization of image guided permanent prostate implants},
author = {Robert A. Cormack; Paul L. Nguyen; Anthony V. D'Amico; Sri Sridhar; Mike Makrigiorgos
},
doi = {10.1117/12.878139},
year = {2011},
date = {2011-03-03},
journal = {Proceedings Volume 7964, Medical Imaging 2011: Visualization, Image-Guided Procedures, and Modeling},
volume = {7964},
number = {2011},
abstract = {Planned in-situ radiosensitization may improve the therapeutic ratio of image guided 125I prostate brachytherapy. Spacers used in permanent implants may be manufactured from a radiosensitizer-releasing polymer to deliver protracted localized sensitization of the prostate. Such devices will have a limited drug-loading capacity, and the drug release schedule that optimizes outcome, under such a constraint, is not known. This work determines the optimal elution schedules for 125I prostate brachytherapy. The interaction between brachytherapy dose distributions and drug distribution around drug eluting spacers is modeled using a linear-quadratic (LQ) model of cell kill. Clinical brachytherapy plans were used to calculate the biologic effective dose (BED) for planned radiation dose distributions while adding the spatial distributions of radiosensitizer while varying the temporal release schedule subject to a constraint on the drug capacity of the eluting spacers. Results: The greatest increase in BED is achieved by schedules with the greatest sensitization early in the implant. Making brachytherapy spacers from radiosensitizer eluting polymer transforms inert parts of the implant process into a means of enhancing the effect of the brachytherapy radiation. Such an approach may increase the therapeutic ratio of prostate brachytherapy or offer a means of locally boosting the radiation effect without increasing the radiation dose to surrounding tissues.
},
keywords = {featured, Nanomedicine},
pubstate = {published},
tppubtype = {article}
}
Planned in-situ radiosensitization may improve the therapeutic ratio of image guided 125I prostate brachytherapy. Spacers used in permanent implants may be manufactured from a radiosensitizer-releasing polymer to deliver protracted localized sensitization of the prostate. Such devices will have a limited drug-loading capacity, and the drug release schedule that optimizes outcome, under such a constraint, is not known. This work determines the optimal elution schedules for 125I prostate brachytherapy. The interaction between brachytherapy dose distributions and drug distribution around drug eluting spacers is modeled using a linear-quadratic (LQ) model of cell kill. Clinical brachytherapy plans were used to calculate the biologic effective dose (BED) for planned radiation dose distributions while adding the spatial distributions of radiosensitizer while varying the temporal release schedule subject to a constraint on the drug capacity of the eluting spacers. Results: The greatest increase in BED is achieved by schedules with the greatest sensitization early in the implant. Making brachytherapy spacers from radiosensitizer eluting polymer transforms inert parts of the implant process into a means of enhancing the effect of the brachytherapy radiation. Such an approach may increase the therapeutic ratio of prostate brachytherapy or offer a means of locally boosting the radiation effect without increasing the radiation dose to surrounding tissues.
