Closing the Nuclear Fuel Cycle with a Simplified Minor Actinide Lanthanide Separation Process (ALSEP) and Additive Manufacturing

Expanded low-carbon baseload power production through the use of nuclear fission can be enabled by recycling long-lived actinide isotopes within the nuclear fuel cycle. This approach provides the benefits of (a) more completely utilizing the energy potential of mined uranium, (b) reducing the footprint of nuclear geological repositories, and (c) reducing the time required for the radiotoxicity of the disposed waste to decrease to the level of uranium ore from one hundred thousand years to a few hundred years. A key step in achieving this goal is the separation of long-lived isotopes of americium (Am) and curium (Cm) for recycle into fast reactors. To achieve this goal, a novel process was successfully demonstrated on a laboratory scale using a bank of 1.25-cm centrifugal contactors, fabricated by additive manufacturing, and a simulant containing the major fission product elements. Americium and Cm were separated from the lanthanides with over 99.9% completion. The sum of the impurities of the Am/Cm product stream using the simulated raffinate was found to be 3.2 × 10−3 g/L. The process performance was validated using a genuine high burnup used nuclear fuel raffinate in a batch regime. Separation factors of nearly 100 for 154Eu over 241Am were achieved. All these results indicate the process scalability to an engineering scale

Microfluidic Blood Cell Sorting: Now and Beyond

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/106971/1/smll201302907.pd

Molecular to Microscale Technologies for Immunoaffinity Based Tumor Cell Capture in Microchannels

In the later stages of cancer, carcinoma cells are shed into the blood stream to become circulating tumor cells (CTCs). These cells spread cancer throughout the body in the deadly process known as tumor metastasis. CTCs are present at extremely low concentrations in the blood, making them difficult to isolate and study. In order to develop new life-saving cancer treatments, clinicians and researchers need to learn more about CTCs and the processes of change that allow them to travel the bloodstream and colonize new tissues. To help meet this need, a new method for CTC isolation was recently developed that utilizes immunoaffinity to antibodies immobilized on microchannel surfaces to bind and sequester CTCs. We have investigated a number of methods for improving the efficiency and purity of this microfluidic immunoaffinity based tumor cell isolation. These include: a biomimetic combination of cell capture proteins, surface protein patterning, microfluidic mixers, and dendrimer facilitated multivalent binding. Furthermore, we have developed a blood analog for use in the initial validation of microfluidic CTC isolation devices

Optimization of Protein Immobilization in Microfludic Devices for Circulating Tumor Cell Capture

The isolation of metastatic circulating tumor cells (CTCs) within the blood using microfluidic devices is a promising method for the detection of cancer. In this study, protein patterning of endothelial-leukocyte adhesion molecule-1 (E-selectin) and anti-epitheal-cell-adhesion-molecule (Anti-EpCAM) within microfluidic channels is utilized to improve the capture efficiency. To create this protein patterning the protein immobilization method must first be optimized to allow for maximum capture of CTCs and minimal increase in the flow rate of cells through the device due to added coating thickness. Proteins are immobilized in alternating regions using photo-initiated graft polymerization of polyacrylic acid (PAA) and a silanization reaction. Using interferometer measurements and fluorescent tagging, PAA height was minimized and protein immobilization was optimized.</jats:p

High Precision Droplet-Based Microfluidic Determination of Americium(III) and Lanthanide(III) Solvent Extraction Separation Kinetics

A new method for studying solvent extraction kinetics has been applied for measuring americium and lanthanide extraction rate constants. This droplet-based microfluidic method uses commercially available components and provides rapid, high throughput and accurate determination of absolute interfacial mass transfer rate constants. Reported for the first time are americium extraction rates relevant to TALSPEAK-type process conditions, including the americium and lanthanide rate dependencies on pH and extractant power

Enhanced Tumor Cell Isolation by a Biomimetic Combination of E-selectin and anti-EpCAM: Implications for the Effective Separation of Circulating Tumor Cells (CTCs)

The selective detection of circulating tumor cells (CTCs) is of significant clinical importance for the clinical diagnosis and prognosis of cancer metastasis. However, largely because of the extremely low number of CTCs (as low as 1 in 109 hematologic cells) in the blood of patients, effective detection and separation of the rare cells remain a tremendous challenge. Cell rolling is known to play a key role in physiological processes such as the recruitment of leukocytes to sites of inflammation and selectin-mediated CTC metastasis. Furthermore, because CTCs typically express the epithelial-cell adhesion molecule (EpCAM) on the surface whereas normal hematologic cells do not, substrates with immobilized antibody against EpCAM may specifically interact with CTCs. In this article, we created biomimetic surfaces functionalized with P- and E-selectin and anti-EpCAM that induce different responses in HL-60 (used as a model of leukocytes in this study) and MCF-7 (a model of CTCs) cells. HL-60 and MCF-7 cells showed different degrees of interaction with P-/E-selectin and anti-EpCAM at a shear stress of 0.32 dyn/cm2. HL-60 cells exhibited rolling on P-selectin-immobilized substrates at a velocity of 2.26 ± 0.28 μm/s whereas MCF-7 cells had no interaction with the surface. Both cell lines, however, had interactions with E-selectin, and the rolling velocity of MCF-7 cells (4.24 ± 0.31 μm/s) was faster than that of HL-60 cells (2.12 ± 0.15 μm/s). However, only MCF-7 cells interacted with anti-EpCAM-coated surfaces, forming stationary binding under flow. More importantly, the combination of the rolling (E-selectin) and stationary binding (anti-EpCAM) resulted in substantially enhanced separation capacity and capture efficiency (more than 3-fold enhancement), as compared to a surface functionalized solely with anti-EpCAM that has been commonly used for CTC capture. Our results indicate that cell-specific detection and separation may be achieved through mimicking the biological processes of combined dynamic cell rolling and stationary binding, which will likely lead to a CTC detection device with significantly enhanced specificity and sensitivity without a complex fabrication process