Variations in sample preparation may contribute to major discrepancies in the quantity and type of biomolecules or cells identified by different laboratories, even though the same reagents and biosensors (or biochips) are employed. This is especially hampering our efforts to fight cancer as sample preparation is a prerequisite for cancer biomarker discovery, validation, and their use in molecular diagnosis and treatment of patients. This urgent need for cancer sample preparation requires innovative methods to bring about better and more affordable sample preparation tools. We have formed an interdisciplinary team with expertise from magnetics, nanotechnology, cancer clinical practice and research, biochemistry, and proteomics to work on a novel micromachined magnetic sifter and directly fabricated magnetic nanoparticles. The magnetic sifter can be used to separate and enrich cancer targets;including proteins and rare cells from raw samples. The utilization of precisely dimensioned structures, including the use of sub-nanometer control of quantum magnetic effects will enable high throughput, high capture yield, low impurities, and low cost. The technology is very unique because high magnetic field gradients (>1 Tesla/ 5m) and large flow rates (>1 mL/hour) are enabled by three-dimensional Si-based micromachining. The use of high-moment magnetic nanoparticles with distinctive shapes and controlled magnetic chain formation give rise to unprecedented capture and release efficiencies, cell damage minimization, enhanced characterization, and run-to-run reproducibility. The proposed project is organized in three aims:
Specific Aim 1. Magnetic sifter for high efficiency capture and analysis of protein cancer markers and cancer cells: a) Construct a magnetic sifter with a high magnetic field gradient (>1 Tesla/ 5m) and large flow rate (>1 mL/hour) and demonstrate the efficient capture, release and analysis of protein cancer markers. b) Use magnetic sifter to capture and release NCI-H1650 lung cancer tumor cells cancer cells spiked into samples of human blood with an overall capture efficiency of >70%, while keeping cells viable.
Specific Aim 2. Functionalization and characterization of novel magnetic nanoparticles for high efficiency high speed magnetic separation.
Specific Aim 3. Magnetic sifter for rare cells capture and analysis from human blood. The utility of the grant includes drastically reducing post-separation analysis and enabling new investigations in areas where rare molecules and cell types are currently too difficult to obtain and analyze. Furthermore, separating protein and cancer markers from high concentration impurities in blood, with 1000-fold enrichment, will enable detection of low abundance cancer markers which are difficult to quantify with conventional technologies. We expect that the tools developed under this grant will have a great impact on the cancer research and treatment community.

Public Health Relevance

Numerous biomedical applications, including cancer diagnostics and treatment, require rapid and precise identification and quantitation of biomolecules and cells present in relevant biological and environmental samples. Sample collection, pre-purification, and preparation procedures are crucial in virtually all molecular and cellular diagnostic analyses. Sample preparation in cancer diagnostics is especially challenging because protein and cell concentrations in human blood samples span over 12 decades of dynamic range. To address these problems, we propose to develop micromachined magnetic sifters and novel synthetic antiferromagnetic nanoparticles for efficiently capturing and enriching protein tumor targets and rare cells which are important cancer markers. This innovative technology offers a new paradigm for preparing samples, with greatly improved sensitivity and specificity, larger signal to noise ratios, and higher throughput. These cancer sample preparation methods will be validated for proteomic profiling, with tools such as mass spectroscopy and magnetic protein micro-arrays, and for cellular profiling, through use of techniques including fluorescence activated cell sorting (FACS) and various microscopies.

National Institute of Health (NIH)
National Cancer Institute (NCI)
Exploratory/Developmental Grants Phase II (R33)
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Special Emphasis Panel (ZCA1-SRLB-V (J1))
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Sorbara, Lynn R
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Stanford University
Engineering (All Types)
Schools of Engineering
United States
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