The authors would like to acknowledge Dr. Matthew Heeney of Boston Children's Hospital/Dana-Farber Cancer Institute and Dr. Farzana Pashankar of Yale-New Haven Hospital for providing sickle cell patient samples. The authors would like to thank Chu H. Yu and Ashwini Joshi for their assistance in testing these samples and compiling the data.
S.T. acknowledges the American Heart Association Scientist Development Grant (15SDG25080056) and the University of Connecticut Research Excellence Program award for financial support of this research. S.K. acknowledges that this material is based upon work supported by the National Science Foundation Graduate Research Fellowship (DGE-1247393).

Ethical Statement: All procedures involving human blood samples were carried out according to the institutional regulations. All protocols were reviewed and approved by the Institutional Review Board. An informed consent was given by all participants.
1. Sample Preparation for Sickle Cell Disease Diagnosis5,8
<ol>
	<li>Prepare a 50 mM solution of gadobutrol in Hank&#39;s Balanced Salt Solution (HBSS).</li>
	<li>Dissolve 10 mM sodium metabisulfite in the gadolinium solution. 
	NOTE: Sodium metabisulfite is toxic by inhalation and strongly irritates skin and tissue. It is a corrosive acid when mixed with water. It may decompose to emit toxic oxide fumes of sulfur and sodium when heated to high temperature.</li>
	<li>Obtain blood sample via either fingerstick or venipuncture.
	<ol>
		<li>Draw blood using a lancing device with a clean, disposable lancet. Apply pressure near the pierced site and wipe the blood droplet formed three to four times before collecting blood using a pipette; take care not to &#34;milk&#34; the finger by squeezing the tissue, as this will result in contamination of the sample with tissue fluid.</li>
		<li>Alternatively, draw blood using standard venipuncture procedures14. 
		NOTE: If samples will be stored for more than a few hours, collect the blood into a vacutainer with an anticoagulant such as EDTA.</li>
	</ol>
	</li>
	<li>Add less than 1 &#181;L of blood to 100 &#181;l of the gadolinium-sodium metabisulfite solution.</li>
</ol>
2. Sample Preparation for WBC Cytometry7
<ol>
	<li>Obtain blood sample via either fingerstick or venipuncture, as in section 1.</li>
	<li>Optional: Lyse RBCs with an RBC lysis buffer. Pipette 5 &#181;L of blood into 500 &#181;L of RBC lysis buffer and incubate at room temperature for 3 - 5 min. 
	NOTE: this may be done to confirm the levitation range of an isolated population of WBCs. However, it is not necessary to perform this step, as the results presented here demonstrate that RBCs levitate at a distinctly lower position than WBCs.</li>
	<li>Dilute whole blood 1:1,000 in 25 mM Gd in HBSS 
	NOTE: if cell lysis was performed, dilute the lysed sample 9:1 lysed sample:250 mM Gd to obtain a sample containing 25 mM Gd.</li>
</ol>
3. Analysis of Samples Using the Magnetic Levitation Platform4,5,6,7,8
<ol>
	<li>Start the magnetic levitation device:
	<ol>
		<li>For the self-contained device, plug in the device, allow it to power up, and place on a flat, level surface.</li>
		<li>For the smartphone-compatible version, launch the smartphone application and swipe left to enter image capture mode, and place on a flat, level surface.</li>
	</ol>
	</li>
	<li>For static magnetic levitation:
	<ol>
		<li>Load the prepared sample into a square glass microcapillary tube by dipping the end into the solution and allowing the sample to fill the capillary via capillary action.</li>
		<li>Seal the end with a tube sealant by slowly pushing one end the capillary into the material.</li>
		<li>Insert the capillary between the magnets of the magnetic levitation device so that only 1 cm of the tube remains visible (please see Figure 3 for an illustration the sample preparation) . 
		NOTE: This step remains the same for both the smartphone-compatible and self-contained device.</li>
		<li>Wait 10 min without disturbing the device or the capillary.</li>
	</ol>
	</li>
	<li>For flow-assisted magnetic levitation:
	<ol>
		<li>Load the sample into the sample tube.</li>
		<li>Connect the inlet tubing between the sample container and microcapillary and connect the outlet tubing between the microcapillary and waste container.</li>
		<li>Set the LED intensity and flow parameters.</li>
	</ol>
	</li>
	<li>Ensure that cells are visible in the field of view, then press the capture button to capture an image (button 3 on the self-contained device and the camera button on the bottom of the screen in the smartphone application). 
	NOTE: If a USB is used to store the images, create a folder called &#34;images&#34; and insert the USB prior to turning on the device. If no drive is present, the device will store the images in its internal memory and transferred later. 
	NOTE: Several images may be captured and analyzed to reduce the risk of anomalies by moving the capillary in or out about &#189; cm between image capturing. 
	NOTE: If the number of cells within the field of view is too high or too low (as detected and reported on the user interface), shift the capillary in or out of the device or prepare another sample.</li>
	<li>Remove the sample and discard the sample according to the institutional or local regulations. Capillaries should be disposed as a sharp.</li>
</ol>
<img alt="Figure 3" src="/files/ftp_upload/55012/55012fig3.jpg" /> 
Figure 3: Sample Preparation and User Interface. (a) The sample preparation procedure involves lancing the subject&#39;s finger, forming a droplet of blood, transferring the blood drop to the sample testing solution, agitating the sample and loading into a capillary tube via capillary action, and inserting the sample into the magnetic levitation device. (b) These sample preparation steps are also displayed on the screen of the device to guide sample preparation. (c) The device includes four buttons: a button to zoom into the sample image in order to properly adjust the focus using the adjustment knob; a button to obtain a single measurement (a 5 s delay is implemented to allow time for the user to insert the sample); a time-lapse measurement (6 images are taken at 5 s intervals); and a button to power off the device after use. Reproduced, with permission, from Yenilmez, et al. 8<a href="http://cloudfront.jove.com/files/ftp_upload/55012/55012fig3large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
4. Image Analysis4,5,6,7,8
<ol>
	<li>Run the image analysis software included on the device for the appropriate sample (cell distribution or cell type separation). 
	NOTE: For the self-contained device, the analysis is performed automatically and displayed on the graphical user interface. For the smartphone-compatible device, to perform the analysis, go to the gallery and select the desired video file to be analyzed.</li>
	<li>Observe and record the output of the analysis displayed on-screen. 
	NOTE: For cell distribution analysis (such as sickle cell disease diagnosis), the output will be the width of confinement of the cell population. 
	NOTE: For cell type separation (such as WBC identification), the output will be an image with the WBC population identified. In order to calculate the number of cells per microliter, multiply the average number of WBCs per image by a factor of 2,000. For example, if 5 WBCs were observed, this would indicate 10,000 WBCs/&#181;L. The normal range is generally considered to be 3,500 - 11,000 WBCs/&#181;L.</li>
	<li>Repeat the analysis by moving the sample tube in or out of the device about &#189; cm and capturing another image to be analyzed as described above. 
	NOTE: It is recommended to repeat the analysis 5 - 6 times per sample to avoid errors.</li>
</ol>

<ol>
	<li>Tasoglu, S., Khoory, J., Tekin, H., Thomas, C., Karnoub, A., Ghiran, I., Demirci, U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Levitational+Image+Cytometry+with+Temporal+Resolution.">Levitational Image Cytometry with Temporal Resolution.</a> Advanced Materials. 27 (26), 3901-3908 (2015).</li><li>Tasoglu, S., Yu, C. H., Liadudanskaya, V., Guven, S., Migliaresi, C., Demirci, U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Magnetic+Levitational+Assembly+for+Living+Material+Fabrication.">Magnetic Levitational Assembly for Living Material Fabrication.</a> Advanced Healthcare Materials. 4 (10), 1469-1476 (2015).</li><li>Tasoglu, S., Yu, C. H., Gungordu, H. I., Guven, S., Vural, T., Demirci, U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Guided+and+magnetic+self-assembly+of+magnetoceptive+gels.">Guided and magnetic self-assembly of magnetoceptive gels.</a> Nature Communications. 5, 4702 (2014).</li><li>Amin, R., Knowlton, S., Yenilmez, B., Hart, A., Joshi, A., Tasoglu, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Smart-phone+Attachable,+Flow-Assisted+Magnetic+Focusing+Device.">Smart-phone Attachable, Flow-Assisted Magnetic Focusing Device.</a> RSC Advances. 6, 93922-93931 (2016).</li><li>Knowlton, S. M., Sencan, I., Aytar, Y., Khoory, J., Heeney, M. M., Ghiran, I. C., Tasoglu, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sickle+Cell+Detection+Using+a+Smartphone.">Sickle Cell Detection Using a Smartphone.</a> Sci Rep. 5, 15022 (2015).</li><li>Knowlton, S., Yu, C. H., Jain, N., Ghiran, I. C., Tasoglu, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Smart-Phone+Based+Magnetic+Levitation+for+Measuring+Densities.">Smart-Phone Based Magnetic Levitation for Measuring Densities.</a> PLoS One. 10 (8), e0134400 (2015).</li><li>Yenilmez, B., Knowlton, S., Tasoglu, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Self-Contained+Handheld+Magnetic+Platform+for+Point+of+Care+Cytometry+in+Biological+Samples+.">Self-Contained Handheld Magnetic Platform for Point of Care Cytometry in Biological Samples .</a> Advanced Materials Technologies. 1, 1600144 (2016).</li><li>Yenilmez, B., Knowlton, S., Yu, C. H., Heeney, M., Tasoglu, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Label-Free+Sickle+Cell+Disease+Diagnosis+Using+a+Low-Cost,+Handheld+Platform.">Label-Free Sickle Cell Disease Diagnosis Using a Low-Cost, Handheld Platform.</a> Adv Mat Tech. 1 (5), 1600100 (2016).</li><li>Bender, M. A., Douthitt Seibel, G., Pagon, R. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> GeneReviews. , (1993).</li><li>Kaul, D. K., Fabry, M. E., Windisch, P., Baez, S., Nagel, R. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Erythrocytes+in+sickle+cell+anemia+are+heterogeneous+in+their+rheological+and+hemodynamic+characteristics.">Erythrocytes in sickle cell anemia are heterogeneous in their rheological and hemodynamic characteristics.</a> J Clin Invest. 72 (1), 22-31 (1983).</li><li>Joiner, C. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gardos+pathway+to+sickle+cell+therapies?.">Gardos pathway to sickle cell therapies?.</a> Blood. 111 (8), 3918-3919 (2008).</li><li>Finch, J. T., Perutz, M. F., Bertles, J. F., D&#246;bler, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structure+of+Sickled+Erythrocytes+and+of+Sickle-Cell+Hemoglobin+Fibers.">Structure of Sickled Erythrocytes and of Sickle-Cell Hemoglobin Fibers.</a> Proc Natl Acad Sci. 70 (3), 718-722 (1973).</li><li>Lew, V. L., Etzion, Z., Bookchin, R. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dehydration+response+of+sickle+cells+to+sickling-induced+Ca(++)+permeabilization.">Dehydration response of sickle cells to sickling-induced Ca(++) permeabilization.</a> Blood. 99 (7), 2578-2585 (2002).</li><li>Ernst, D. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> NCCLS Procedures for the Collection of Diagnostic Blood Specimens by Venipuncture: Approved Standard-Sixth Addition. 27 (26), (2007).</li></ol>

Authors Stephanie Knowlton and Savas Tasoglu are founders of and have an equity interest in mBiotics, a startup working to commercialize the magnetic levitation platform described herein for point of care diagnostic solutions. A provisional patent entitled "Magnetic Levitation with On-Board Optical Imaging and Image Analysis for Density-Based Separation, Identification, And Measurement" has been filed with UCONN Case No. 16-027 on the technology described here.

Critical Steps within the Protocol 
Critical factors in this process include the proper alignment of the magnets. If the magnets become dislodged or separated more than normal within the device, this can affect the results. To control for this fault or others in the process, a density-controlled particle, such as polystyrene microspheres, can be used periodically to control for changes over time. Further, levitation time is important to allow the cells to reach equilibrium. For red blood cells, 10 min is sufficient ...

Here, we present a technology platform and a technique which uses magnetic levitation coupled with automated imaging and analysis to analyze the density distribution of a patient&#39;s cells as an indicator for disease. This versatile approach for density-based cytometric analysis can ultimately be applied to a range of disease diagnostics. However, in order to be compatible with point-of-care testing and use in developing countries, the technique must satisfy requirements for low cost, portability, and usability. The device and consumables must be easily obtained at a low cost. The sample preparation must be simple, analysis should be automated with minimal requirements for user input or interpretation, and results should be returned quickly. Further, the device must be compact and portable to be useful in clinical settings as well as developing countries. Thus, we have developed a device and method to use magnetic levitation in point-of-care-compatible technology by coupling automated imaging and image analysis to return results regarding the density distribution of a population of a patient&#39;s cells.
Point-of-care technologies offer a notable advantage over current clinical laboratory testing procedures. The technology currently available is too expensive to be owned by a clinician or too complex to be carried out by medical staff. Many of these procedures require labor-intensive protocols which must be carried out by a trained technician. For these reasons, patient samples such as blood or urine are generally collected in the physician&#39;s office then transferred to a remote, centralized testing laboratory for clinical testing, which may take several days for the physician to receive the results of the test. This can cause delays or complications in the course of treatment in some cases, makes this testing very costly and inefficient (causing a financial burden on insurance payers), and further makes many diagnostics inaccessible in low-resource settings and developing countries.
Here, we present a magnetic levitation technique coupled with automated imaging and analysis in both a device with embedded imaging and processing (Figure 1) and a smartphone-compatible device (Figure 2). These magnetic levitation-based devices represent a broadly applicable platform technology which has the potential to be applied to a range of different medical diagnostic applications. The magnetic levitation approach functions based on an equilibrium between two forces: a magnetic force and a buoyancy force1,2,3. When a particle is suspended in a paramagnetic medium and inserted into a magnetic field generated by two magnets with like poles facing each other, a magnetic force acts on the particle in the direction toward the centerline between the two magnets. The buoyancy force is caused by the relative density of the particle compared to the suspending medium and is upward in the case of particles less dense than the medium and downward in the case of particles denser than the surrounding medium. Based on these two forces, particles will reach an equilibrium levitation position in the field which balances these two forces; this position is directly related to the density of the particle, with denser particles levitating lower in the field than less dense particles. An imaging module, either a built-in smartphone camera4,5,6 or independent optical components equipped with a magnifying lens7,8, are used to visualize the positions of the particles. Image processing, either through a smartphone application4,5,6 or an embedded processing unit7,8, then processes the captured images to quantify the spatial distribution and, therefore, the density distribution of the population. In order to analyze larger samples (such as those with only a few particles of interest per milliliter, flow can be integrated directly into the device such the particles are levitated and analyzed as they pass through the imaging region (Figure 2).
<img alt="Figure 1" src="/files/ftp_upload/55012/55012fig1.jpg" /> 
Figure 1: Self-contained Magnetic Levitation Platform. (a) Compact magnetic levitation device including a magnetic focusing module, imaging components (a light-emitting diode (LED), an optical lens, and a camera detector), and a processing unit with a display screen. (b) Magnetic field strength in the cross-section of the area between the magnets where the sample is inserted. The field strength is greatest at the surface of the magnets and approaches zero at the centerline between them. (c) Particles, such as cells, within the magnetic field experience several forces: a magnetic force (Fm) toward the centerline between the magnetics, with magnitude varying based on the position of the particle; a gravitational force (Fg&#39;) which depends on the particle density relative to that of the suspending medium, and a drag force (Fd) resisting the particle motion. Reproduced, with permission, from Yenilmez, et al.8 <a href="http://cloudflare.jove.com/files/ftp_upload/55012/55012fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 2" src="/files/ftp_upload/55012/55012fig2.jpg" /> 
Figure 2: Smartphone-compatible Flow-assisted Magnetic Levitation Platform. (a-c) Front (a), side (b), and back (c) views of magnetic levitation device (d) The components of the device include: 1) Magnetic levitation module, including permanent magnets, a magnifying lens, and an LED and light diffuser, 2) smartphone case, 3) electronics, including a microcontroller, pump driver, and Bluetooth receiver, 4) micro-pump holder, 5) adjustable orifice, 6) waste tube holder, 7) battery holder, 8) sample holder, 9) dual-purpose stand and cover. (e) Flow schematic, showing pumping of the sample through the magnetic field. (f) Cross-section of the magnetic levitation module, showing how particles of different densities will align as they are pumped through the field; less dense particles, such as Particle 1, will equilibrate at a higher levitation height than denser particles, such as Particle 2. Reproduced, with permission, from Amin, et al.1 <a href="http://cloudflare.jove.com/files/ftp_upload/55012/55012fig2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
The minimum requirements for use of any sample for density distribution analysis in this system include the ability to obtain a suspension of cells or particles greater than approximately 5 &#181;m and less than approximately 250 &#181;m in size (for imaging and image processing) and its compatibility with mixing in a solution of a paramagnetic solution such as the gadobutrol used here. For disease diagnostics, compatible applications include those in which (i) cells of interest inherently have an altered density when they carry a disease compared to healthy controls, (ii) a density change can be induced in the cell by addition of a reagent or some alternative treatment for a short incubation time, or (iii) different cell types are being identified in a single sample and inherently (or via some treatment) have unique characteristic densities.
Sickle cell disease is a genetic disorder causing a mutated form of hemoglobin, HbS, to be produced in a person&#39;s red blood cells (RBCs), which can result in intermittent vaso-occlusive events and chronic hemolytic anemia9. It is diagnosed using either hemoglobin isoelectric focusing, high-performance liquid chromatography (HPLC) fractionation, or hemoglobin electrophoresis which are highly accurate but must be performed in a clinical testing laboratory because they are incompatible with point-of-care settings. Solubility and paper-based tests for sickle cell disease have been proposed, but generally require subjective user interpretation and confirmatory testing. Here, we use a density-based approach to identify sickle RBCs, which attain a higher density than RBCs from people without sickle cell disease. The mechanism involves polymerization of the mutated form of hemoglobin, HbS, which causes RBC dehydration in sickle cell disease RBCs under deoxygenated conditions10,11,12,13.
This density-based approach can also be applied to separate cells of different types on the basis of density: white blood cells (WBCs) and RBCs7. WBCs are generally responsible for fighting infections in the body. WBC cytometry can be used to quantify the number of these cells in the blood and serves as a useful diagnostic tool. WBC counts higher than normal (generally considered greater than 11,000 cells per &#181;L) may indicate infection, immune system disorders, or leukemia. WBC counts below the normal range (around 3,500 cells per &#181;L) may be caused by autoimmune disorders or conditions which damage bone marrow. Unlike alternative technologies, the process presented here does not rely on lysis of the RBCs or stains in order to identify WBCs. This cell-based test takes advantage of the unique inherent densities of the two cell types to perform separation, as the WBC population density has been reported to be lower than that of the RBC population as calculated previously using density gradient centrifugation1,5,8.
Compared to alterative testing at remote locations, this test is rapid, with simple sample preparation (Figure 3), separation of cells in the device within 10 - 15 min, and automated imaging and analysis which requires less than 1 min. In this way, the device can return results quickly to better inform medical decisions, allow treatment to be administered immediately to alleviate physical and psychological pain, and reduce the risk of complications associated with a delay in medical care. This technique can be performed on-site either in clinical settings due to simple sample preparation and automated imaging and analysis which returns a result with minimal user input or interpretation. Because of the use of a simple approach using permanent magnets for sample analysis and the use of either a smartphone or simple electrical components for imaging and image processing, the device as well as the per-test costs are minimal compared to some sophisticated testing procedures.

<table border="0" cellpadding="0" cellspacing="0" width="938">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:321px;">Gadavist (Bayer)</td>
			<td style="width:257px;">Jefferson Medical and Imaging</td>
			<td style="width:119px;">2068062</td>
			<td style="width:241px;">Gadavist contains 1M gadobutrol, a chelate of gadolinium. We purchased 2 mL vials with 15/ca.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:321px;">Square glass microcapillary tubes</td>
			<td style="width:257px;">Vitrocom</td>
			<td style="width:119px;">8270</td>
			<td>50 mm length is sufficient</td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:321px;">Sodium metabisulfite</td>
			<td style="width:257px;">Sigma-Aldrich</td>
			<td style="width:119px;">S9000</td>
			<td>Chemical formula: Na2S2O5</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:321px;">Leica Microsystems Critoseal tube sealant</td>
			<td style="width:257px;">Fisher Scientific</td>
			<td style="width:119px;">02-676-20</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:321px;">Hank&#39;s Balanced Salt Solution</td>
			<td style="width:257px;">Sigma-Aldrich</td>
			<td style="width:119px;">H9269&#160;SIGMA</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:321px;">Trypsin-EDTA</td>
			<td style="width:257px;">Sigma-Aldrich</td>
			<td style="width:119px;">T4049</td>
			<td>Or other reagent as recommended for the cell type used</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:321px;">MICROLET 2 Adjustable Lancing Device</td>
			<td style="width:257px;">Walgreens</td>
			<td style="width:119px;">246567</td>
			<td>Any lancing device is acceptable when used according to biosafety protocols</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:321px;">Microlet Lancets</td>
			<td style="width:257px;">Walgreens</td>
			<td style="width:119px;">667474</td>
			<td>Must be dispoable and not reused</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:321px;">Hausser Bright-Line Phase Hemacytometer</td>
			<td style="width:257px;">Fisher Scientific</td>
			<td style="width:119px;">02-671-6</td>
			<td>Or any preferred method for cell counting</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:321px;">ACK Lysing Buffer</td>
			<td style="width:257px;">ThermoFisher</td>
			<td style="width:119px;">A1049201&#160;</td>
			<td></td>
		</tr>
	</tbody>
</table>

magnetic levitation coupled with portable imaging and analysis for disease diagnostics

Currently, many clinical diagnostic procedures are complex, costly, inefficient, and inaccessible to a large population in the world. The requirements for specialized equipment and trained personnel require that many diagnostic tests be performed at remote, centralized clinical laboratories. Magnetic levitation is a simple yet powerful technique and can be applied to levitate cells, which are suspended in a paramagnetic solution and placed in a magnetic field, at a position determined by equilibrium between a magnetic force and a buoyancy force. Here, we present a versatile platform technology designed for point-of-care diagnostics which uses magnetic levitation coupled to microscopic imaging and automated analysis to determine the density distribution of a patient's cells as a useful diagnostic indicator. We present two platforms operating on this principle: (i) a smartphone-compatible version of the technology, where the built-in smartphone camera is used to image cells in the magnetic field and a smartphone application processes the images and to measures the density distribution of the cells and (ii) a self-contained version where a camera board is used to capture images and an embedded processing unit with attached thin-film-transistor (TFT) screen measures and displays the results. Demonstrated applications include: (i) measuring the altered distribution of a cell population with a disease phenotype compared to a healthy phenotype, which is applied to sickle cell disease diagnosis, and (ii) separation of different cell types based on their characteristic densities, which is applied to separate white blood cells from red blood cells for white blood cell cytometry. These applications, as well as future extensions of the essential density-based measurements enabled by this portable, user-friendly platform technology, will significantly enhance disease diagnostic capabilities at the point of care.

For cell density distribution analysis, which is the technique used for sickle cell disease diagnosis, the aim is to identify the width of the distribution of the cell population. Blood cells from patients without sickle cell disease will be confined within a predictable width. Cells from patients with sickle cell disease will be distributed throughout a wider region, with a downward skew in the cell distribution (see Figure 4.) For any particular application, a threshold...

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Magnetic Levitation Coupled with Portable Imaging and Analysis for Disease Diagnostics

We present a magnetic levitation technique coupled with automated imaging and analysis in both a smartphone-compatible device and a device with embedded imaging and processing. This is applied to measure the density distribution of cells with two demonstrated biomedical applications: sickle cell disease diagnosis and separating white and red blood cells.

Currently, many clinical diagnostic procedures are complex, costly, inefficient, and inaccessible to a large population in the world. The requirements for ...

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8.7K Views.  University of Connecticut. We present a magnetic levitation technique coupled with automated imaging and analysis in both a smartphone-compatible device and a device with embedded imaging and processing. This is applied to measure the density distribution of cells with two demonstrated biomedical applications: sickle cell disease diagnosis and separating white and red blood cells.

Video: Magnetic Levitation Coupled with Portable Imaging and Analysis for Disease Diagnostics

Hybrid &#181;CT-FMT imaging and image analysis

Fluorescence-mediated tomography (FMT) enables longitudinal and quantitative determination of the fluorescence distribution in vivo and can be used to assess the biodistribution of novel probes and to assess disease progression using established molecular probes or reporter genes. The combination with an anatomical modality, e.g., micro computed tomography (&#181;CT), is beneficial for image analysis and for fluorescence reconstruction. We describe a protocol for multimodal &#181;CT-FMT imaging including the image processing steps necessary to extract quantitative measurements. After preparing the mice and performing the imaging, the multimodal data sets are registered. Subsequently, an improved fluorescence reconstruction is performed, which takes into account the shape of the mouse. For quantitative analysis, organ segmentations are generated based on the anatomical data using our interactive segmentation tool. Finally, the biodistribution curves are generated using a batch-processing feature. We show the applicability of the method by assessing the biodistribution of a well-known probe that binds to bones and joints.

Hybrid  &#181;CT-FMT imaging and image analysis

We describe a protocol for hybrid imaging, combining fluorescence-mediated tomography (FMT) with micro computed tomography (&#181;CT). After fusion and reconstruction, we perform interactive organ segmentation to extract quantitative measurements of the fluorescence distribution.

Fluorescence-mediated tomography (FMT) enables longitudinal and quantitative determination of the fluorescence distribution in vivo and can be used to ...

Rapid Scan Electron Paramagnetic Resonance Opens New Avenues for Imaging Physiologically Important Parameters In Vivo

We demonstrate a superior method of 2D spectral-spatial imaging of stable radical reporter molecules at 250 MHz using rapid-scan electron-paramagnetic-resonance (RS-EPR), which can provide quantitative information under in vivo conditions on oxygen concentration, pH, redox status and concentration of signaling molecules (i.e., OH&#8226;, NO&#8226;). The RS-EPR technique has a higher sensitivity, improved spatial resolution (1 mm), and shorter acquisition time in comparison to the standard continuous wave (CW) technique. A variety of phantom configurations have been tested, with spatial resolution varying from 1 to 6 mm, and spectral width of the reporter molecules ranging from 16 &#181;T (160 mG) to 5 mT (50 G). A cross-loop bimodal resonator decouples excitation and detection, reducing the noise, while the rapid scan effect allows more power to be input to the spin system before saturation, increasing the EPR signal. This leads to a substantially higher signal-to-noise ratio than in conventional CW EPR experiments.

Rapid Scan Electron Paramagnetic Resonance Opens New Avenues for Imaging Physiologically Important Parameters In Vivo

A new electron paramagnetic resonance (EPR) method, rapid scan EPR (RS-EPR), is demonstrated for 2D spectral spatial imaging which is superior to the traditional continuous wave (CW) technique and opens new venues for in vivo imaging. Results are demonstrated at 250 MHz, but the technique is applicable at any frequency.

We demonstrate a superior method of 2D spectral-spatial imaging of stable radical reporter molecules at 250 MHz using rapid-scan ...

Optimized Setup and Protocol for Magnetic Domain Imaging with In Situ Hysteresis Measurement

This paper elaborates the sample preparation protocols required to obtain optimal domain patterns using the Bitter method, focusing on the extra steps compared to standard metallographic sample preparation procedures. The paper proposes a novel bespoke rig for dynamic domain imaging with in situ BH (magnetic hysteresis) measurements and elaborates the protocols for the sensor preparation and the use of the rig to ensure accurate BH measurement. The protocols for static and ordinary dynamic domain imaging (without in situ BH measurements) are also presented. The reported method takes advantage of the convenience and high sensitivity of the traditional Bitter method and enables in situ BH measurement without interrupting or interfering with the domain wall movement processes. This facilitates establishing a direct and quantitative link between the domain wall movement processes&#8211;microstructural feature interactions in ferritic steels with their BH loops. This method is anticipated to become a useful tool for the fundamental study of microstructure&#8211;magnetic property relationships in steels and to help interpret the electromagnetic sensor signals for non-destructive evaluation of steel microstructures.

Optimized Setup and Protocol for Magnetic Domain Imaging with In Situ Hysteresis Measurement

This paper elaborates the sample and sensor preparation procedures and the protocols for using the test rig particularly for dynamic domain imaging with in situ BH measurements in order to achieve optimal domain pattern quality and accurate BH measurements.

This paper elaborates the sample preparation protocols required to obtain optimal domain patterns using the Bitter method, focusing on the extra steps ...

Nanosensors to Detect Protease Activity In Vivo for Noninvasive Diagnostics

Proteases are multi-functional enzymes that specialize in the hydrolysis of peptide-bonds and control broad biological processes including homeostasis and allostasis. Moreover, dysregulated protease activity drives pathogenesis and is a functional biomarker of diseases such as cancer; therefore, the ability to detect protease activity in vivo may provide clinically relevant information for biomedical diagnostics. The goal of this protocol is to create nanosensors that probe for protease activity in vivo by producing a quantifiable signal in urine. These protease nanosensors consist of two components: a nanoparticle and substrate. The nanoparticle functions to increase circulation half-life and substrate delivery to target disease sites. The substrate is a short peptide sequence (6-8 AA), which is designed to be specific to a target protease or group of proteases. The substrate is conjugated to the surface of the nanoparticle and is terminated by a reporter, such as a fluorescent marker, for detection. As dysregulated proteases cleave the peptide substrate, the reporter is filtered into urine for quantification as a biomarker of protease activity. Herein we describe construction of a nanosensor for matrix metalloproteinase 9 (MMP9), which is associated with tumor progression and metastasis, for detection of colorectal cancer in a mouse model.

Nanosensors to Detect Protease Activity In Vivo for Noninvasive Diagnostics

Proteases are tightly regulated enzymes involved in fundamental biological processes, and dysregulated protease activity drives progression of complex diseases such as cancer. This method&#39;s goal is to create nanosensors that measure protease activity in vivo by producing a cleavage signal that is detectable from host urine and discriminates disease.

Proteases are multi-functional enzymes that specialize in the hydrolysis of peptide-bonds and control broad biological processes including homeostasis and ...

Using Nanoplasmon-Enhanced Scattering and Low-Magnification Microscope Imaging to Quantify Tumor-Derived Exosomes

Infected or malignant cells frequently secrete more exosomes, leading to elevated levels of disease-associated exosomes in the circulation. These exosomes have the potential to serve as biomarkers for disease diagnosis and to monitor disease progression and treatment response. However, most exosome analysis procedures require exosome isolation and purification steps, which are usually time-consuming and labor-intensive, and thus of limited utility in clinical settings. This report describes a rapid procedure to analyze specific biomarkers on the outer membrane of exosomes without requiring separate isolation and purification steps. In this method, exosomes are captured on the surface of a slide by exosome-specific antibodies and then hybridized with nanoparticle-conjugated antibody probes specific to a disease. After hybridization, the abundance of the target exosome population is determined by analyzing low-magnification dark-field microscope (LMDFM) images of the bound nanoparticles. This approach can be easily adopted for research and clinical use to analyze membrane-associated exosome biomarkers linked to disease.

Clinical translation of exosome-derived biomarkers for diseased and malignant cells is hindered by the lack of rapid and accurate quantification methods. This report describes the use of low-magnification dark-field microscope images to quantify specific exosome subtypes in small volume serum or plasma samples.

Infected or malignant cells frequently secrete more exosomes, leading to elevated levels of disease-associated exosomes in the circulation. These exosomes ...

Measuring the Spin-Lattice Relaxation Magnetic Field Dependence of Hyperpolarized [1-13C]pyruvate

The fundamental limit to in vivo imaging applications of hyperpolarized 13C-enriched compounds is their finite spin-lattice relaxation times. Various factors affect the relaxation rates, such as buffer composition, solution pH, temperature, and magnetic field. In this last regard, the spin-lattice relaxation time can be measured at clinical field strengths, but at lower fields, where these compounds are dispensed from the polarizer and transported to the MRI, the relaxation is even faster and difficult to measure. To have a better understanding of the amount of magnetization lost during transport, we used fast field-cycling relaxometry, with magnetic resonance detection of 13C nuclei at ~0.75 T, to measure the nuclear magnetic resonance dispersion of the spin-lattice relaxation time of hyperpolarized [1-13C]pyruvate. Dissolution dynamic nuclear polarization was used to produce hyperpolarized samples of pyruvate at a concentration of 80 mmol/L and physiological pH (~7.8). These solutions were rapidly transferred to a fast field-cycling relaxometer so that relaxation of the sample magnetization could be measured as a function of time using a calibrated small flip angle (3&#176;-5&#176;). To map the T1 dispersion of the C-1 of pyruvate, we recorded data for different relaxation fields ranging between 0.237 mT and 0.705 T. With this information, we determined an empirical equation to estimate the spin-lattice relaxation of the hyperpolarized substrate within the mentioned range of magnetic fields. These results can be used to predict the amount of magnetization lost during transport and to improve experimental designs to minimize signal loss.

Measuring the Spin-Lattice Relaxation Magnetic Field Dependence of Hyperpolarized [1-13C]pyruvate

We present a protocol to measure the magnetic field dependence of the spin-lattice relaxation time of 13C-enriched compounds, hyperpolarized by means of dynamic nuclear polarization, using fast field-cycled relaxometry. Specifically, we have demonstrated this with [1-13C]pyruvate, but the protocol could be extended to other hyperpolarized substrates.

The fundamental limit to in vivo imaging applications of hyperpolarized 13C-enriched compounds is their finite spin-lattice relaxation times. Various ...

Magnetic-, Acoustic-, and Optical-Triple-Responsive Microbubbles for Magnetic Hyperthermia and Pothotothermal Combination Cancer Therapy

The precision delivery of anti-cancer agents which aim for targeted and deep-penetrated delivery as well as a controlled release at the tumor site has been challenged. Here, we fabricate iron oxide nanoparticle shelled microbubbles (NSMs) through self-assembly, synergizing magnetic, acoustic, and optical responsiveness in one nanotherapeutic platform. Iron oxide nanoparticles serve as both magnetic and photothermal agents. Once intravenously injected, NSMs can be magnetically guided to the tumor site. Ultrasound triggers the release of iron oxide nanoparticles, facilitating the penetration of nanoparticles deep into the tumor due to the cavitation effect of microbubbles. Thereafter, magnetic hyperthermia and photothermal therapy can be performed on the tumor for combinational cancer therapy, a solution for cancer resistance due to the tumor heterogeneity. In this protocol, the synthesis and characterization of NSMs including structural, chemical, magnetic and acoustic properties were performed. In addition, the anti-cancer efficacy by thermal therapy was investigated using in vitro cell cultures. The proposed delivery strategy and combination therapy holds great promise in cancer treatment to improve both delivery and anticancer efficacies.

Presented here is a protocol for the fabrication of iron oxide nanoparticle-shelled microbubbles (NSMs) through self-assembly, synergizing magnetic, acoustic, and optical responsiveness in one nanotherapeutic platform for magnetic hyperthermia and photothermal combination cancer therapy.

The precision delivery of anti-cancer agents which aim for targeted and deep-penetrated delivery as well as a controlled release at the tumor site has ...

High-Dimensionality Flow Cytometry for Immune Function Analysis of Dissected Implant Tissues

The success of implanting laboratory-grown tissue or a medical device in an individual is subject to the immune response of the recipient host. Considering an implant as a foreign body, a hostile and dysregulated immune response may result in the rejection of the implant, while a regulated response and regaining of homeostasis can lead to its acceptance. Analyzing the microenvironments of implants dissected out under in vivo or ex vivo&#160;settings can help in understanding the pattern of immune response, which can ultimately help in developing new generations of biomaterials. Flow cytometry is a well-known technique for characterizing immune cells and their subsets based on their cell surface markers. This review describes a protocol based on manual dicing, enzymatic digestion, and filtration through a cell strainer for the isolation of uniform cell suspensions from dissected implant tissue. Further, a multicolor flow cytometry staining protocol has been explained, along with steps for initial cytometer settings to characterize and quantify these isolated cells by flow cytometry.

Isolation of cells from dissected implants and their characterization by flow cytometry can significantly contribute to understanding the pattern of immune response against implants. This paper describes a precise method for the isolation of cells from dissected implants and their staining for flow cytometric analysis.

The success of implanting laboratory-grown tissue or a medical device in an individual is subject to the immune response of the recipient host. ...

Quantifying Fibrillar Collagen Organization with Curvelet Transform-Based Tools

Fibrillar collagens are prominent extracellular matrix (ECM) components, and their topology changes have been shown to be associated with the progression of a wide range of diseases including breast, ovarian, kidney, and pancreatic cancers. Freely available fiber quantification software tools are mainly focused on the calculation of fiber alignment or orientation, and they are subject to limitations such as the requirement of manual steps, inaccuracy in detection of the fiber edge in noisy background, or lack of localized feature characterization. The collagen fiber quantitation tool described in this protocol is characterized by using an optimal multiscale image representation enabled by curvelet transform (CT). This algorithmic approach allows for the removal of noise from fibrillar collagen images and the enhancement of fiber edges to provide location and orientation information directly from a fiber, rather than using the indirect pixel-wise or window-wise information obtained from other tools. This CT-based framework contains two separate, but linked, packages named &#8220;CT-FIRE&#8221; and &#8220;CurveAlign&#8221; that can quantify fiber organization on a global, region of interest (ROI), or individual fiber basis. This quantification framework has been developed for more than ten years and has now evolved into a comprehensive and user-driven collagen quantification platform. Using this platform, one can measure up to about thirty fiber features including individual fiber properties such as length, angle, width, and straightness, as well as bulk measurements such as density and alignment. Additionally, the user can measure fiber angle relative to manually or automatically segmented boundaries. This platform also provides several additional modules including ones for ROI analysis, automatic boundary creation, and post-processing. Using this platform does not require prior experience of programming or image processing, and it can handle large datasets including hundreds or thousands of images, enabling efficient quantification of collagen fiber organization for biological or biomedical applications.

Here, we present a protocol to use a curvelet transform-based, open-source MATLAB software tool for quantifying fibrillar collagen organization in the extracellular matrix of both normal and diseased tissues. This tool can be applied to images with collagen fibers or other types of line-like structures.

Fibrillar collagens are prominent extracellular matrix (ECM) components, and their topology changes have been shown to be associated with the progression ...

Electric and Magnetic Field Devices for Stimulation of Biological Tissues

Electric fields (EFs) and magnetic fields (MFs) have been widely used by tissue engineering to improve cell dynamics such as proliferation, migration, differentiation, morphology, and molecular synthesis. However, variables such stimuli strength and stimulation times need to be considered when stimulating either cells, tissues or scaffolds. Given that EFs and MFs vary according to cellular response, it remains unclear how to build devices that generate adequate biophysical stimuli to stimulate biological samples. In fact, there is a lack of evidence regarding the calculation and distribution when biophysical stimuli are applied. This protocol is focused on the design and manufacture of devices to generate EFs and MFs and implementation of a computational methodology to predict biophysical stimuli distribution inside and outside of biological samples. The EF device was composed of two parallel stainless-steel electrodes located at the top and bottom of biological cultures. Electrodes were connected to an oscillator to generate voltages (50, 100, 150 and 200 Vp-p) at 60 kHz. The MF device was composed of a coil, which was energized with a transformer to generate a current (1 A) and voltage (6 V) at 60 Hz. A polymethyl methacrylate support was built to locate the biological cultures in the middle of the coil. The computational simulation elucidated the homogeneous distribution of EFs and MFs inside and outside of biological tissues. This computational model is a promising tool that can modify parameters such as voltages, frequencies, tissue morphologies, well plate types, electrodes and coil size to estimate the EFs and MFs to achieve a cellular response.

This protocol describes the step-by-step process to build both electrical and magnetic stimulators used to stimulate biological tissues. The protocol includes a guideline to simulate computationally electric and magnetic fields and manufacture of stimulator devices.

Electric fields (EFs) and magnetic fields (MFs) have been widely used by tissue engineering to improve cell dynamics such as proliferation, migration, ...

Magnetic Levitation Coupled with Portable Imaging and Analysis for Disease Diagnostics

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Hybrid µCT-FMT imaging and image analysis

Rapid Scan Electron Paramagnetic Resonance Opens New Avenues for Imaging Physiologically Important Parameters In Vivo

Optimized Setup and Protocol for Magnetic Domain Imaging with In Situ Hysteresis Measurement

Nanosensors to Detect Protease Activity In Vivo for Noninvasive Diagnostics

Using Nanoplasmon-Enhanced Scattering and Low-Magnification Microscope Imaging to Quantify Tumor-Derived Exosomes

Measuring the Spin-Lattice Relaxation Magnetic Field Dependence of Hyperpolarized [1-¹³C]pyruvate

Magnetic-, Acoustic-, and Optical-Triple-Responsive Microbubbles for Magnetic Hyperthermia and Pothotothermal Combination Cancer Therapy

High-Dimensionality Flow Cytometry for Immune Function Analysis of Dissected Implant Tissues

Quantifying Fibrillar Collagen Organization with Curvelet Transform-Based Tools

Electric and Magnetic Field Devices for Stimulation of Biological Tissues