Senior Research Project Proposal

Senior Research Project Proposal

Siva Kailas

Mentor: Dr. Jian Gu

December 17, 2015

1. Title of Project:

Developing a Self-Administered Finger Prick Blood Collector for Medical Countermeasure Against Radiation

2. Statement of Purpose:

In this project, I hope to develop a self-administered finger prick blood collector for cytogenetic and gene expression biodosimetry assays for medical countermeasure against radiation. The blood collector consists of a finger prick lancet, a capillary tube and a VacuStor tube that will allow individuals affected by a radiological event to self-collect certain amount of finger prick blood for rapid assessment of radiation dose exposed.  The main focus of this project will be on the VacuStor tube, which uses the vacuum in the tube to transfer the collected blood from the capillary to the VacuStor tube. A system will be built that will allow the assembly of the VacuStor device and monitoring of the vacuum inside the tube over time. To meet the program needs, the VacuStor tube needs to have a shelf life of ~ 1 year or longer with assay reagents prestored in the tube, at room temperature or at -20oC. Different parameters will be tested and engineered to meet the goal, including tube material and volume, tube cap material and structure.  Theoretical analysis of gas permeability, vacuum sample transfer capability will be conducted to guide the device design.

3. Background:

In case of a large scale nuclear or radiological event (such as a radiological dispersion device in a large metropolitan area), it is estimated that over 1 million people could seek information on their radiation exposure level. Biodosimetry assays, such as cytogenetic assays and gene expression assays, are critical tools in rapid triage of people for medical treatment.

Previously, many works have focused on the development of the assays themselves. The sample collection, in-field processing, transport and logistics, which can be critical to the assay’s accuracy, speed, and reliability, have not been well addressed. In this project, we aim to develop a self-administered blood collection device and procedures that will enable the rapid and accurate biodosimetry assays by meeting the key challenges of regulatory and assay requirements on the samples.

The VacuStor tube is a key component of the blood collector that uses vacuum to collect fixed volume of blood in a capillary tube. It works similar to the commercial Vacutainer tubes, but with key differences, such as external pressure during collection to be atmospheric pressure without diastolic pressure, smaller tube volume (~ 1 ml versus 4 ml) but expected with similar shelf life etc. These conditions have not been studied previously and will be addressed in this project.

4. Significance

Rapid triage situations, such as those that would occur following a radiological incident, are often chaotic.  It is therefore necessary to develop devices and procedures for analysis which account for the state of disarray. The biological samples analyzed in the proposed projects need to be acquired without relying on medical infrastructure or the knowledge, skills, and ability of trained medical personnel. Assurance of sample integrity, quality, and quantity needs to occur without complications. The sample collection and processing also need to be compatible with the downstream high throughput platforms at clinical laboratories.

Blood analysis is an example of a current sample collection technique that presents many challenges. Blood collection is usually done by a phlebotomist, which is a slow process with requirement of trained personnel. Although capillary blood collection using fingersticks is currently the simplest and most effective method available for rapid blood collection to ensure sample integrity, this method entails multiple processing steps performed by trained specialists. Furthermore, in many states a certified phlebotomist is required even to draw a fingerstick of blood with a lancet.

Development of a simplified, self-administered, all-in-one capillary blood acquisition device will reduce variability in sample collection while also increasing throughput at triage facilities, and is critical to the overall success of the biodosimetry assays for medical countermeasure of nuclear and radiological event.

5. Research Methodology

First, the ability of the VacuStor tube to transfer the desired amount of blood will be calculated theoretically using ideal gas approximation. It is expected that there is a threshold vacuum that only above which success transfer of the desired blood sample can happen. To what degree is this threshold vacuum dependent on the tube volume, prestored reagent volume, blood sample volume and piecing needle gauge (for capillary pressure) will be analyzed.

Second, a system will be built that allows the assembly of VacuStor tubes with different tube volume and prestored reagent volume. Different needles will be used to transfer the target amount of blood samples to verify the theoretical analysis.

Third, shelf life is an important parameter for the proposed VacuStor tube. It is only practical when the tube shelf life is long enough (e.g. 1 year) without being replaced frequently. The shelf life is mainly determined by the rise of the vacuum pressure inside the tube. A setup that can monitor VacuStor tube vacuum over time will be developed. Vacuum pressure rising time constant will be fitted using software and compared with theoretical analysis based on permeability of the tube materials.

6. Anticipated Problems

Before starting experimentation, often a key starting point is to develop a theory behind what we are trying to accomplish. However, a problem that we will most likely face is how far from the theory our experimentation will deviate. Predictions and assumptions of the ideal conditions can help narrow our focus, but how heavily these factors play into the actual production of the VacuStor tube or the device in which the tube will be integrated into.

The biggest issue when fabricating the VacuStor tube will be the shelf life. At such a small volume size, maintenance of a vacuum for extended period of time will be difficult. It will inevitably come down to the materials that we use and their ability to restrict permeability of gas into the tube. The tube has a pressure threshold, which, if exceeded, will fail to draw liquid. Hence, an issue will not only be to maximize the shelf life, but also determine where this threshold is for different combinations of materials.

Currently, we are using glass and plastic for the tube, and a rubberized cap, which are standard in current vacutainers. However, although we are not limited to what materials we can use, we aim to use materials that are easy to utilize for mass fabrication, especially in the midst of a crisis. This can be an issue since there are materials that may be able to reduce permeability of gas and extend shelf life, but may be difficult to utilize for mass fabrication. Hence, we want to determine which set of materials will be the most effective in maintaining the vacuum within the tube without requiring extensive fabrication costs.

7. Bibliography

1. Badie C, Kabacik S, Balagurunathan Y, Bernard N, Brengues M, Faggioni G, Greither R, Lista F, Peinnequin A, Poyot T, Herodin F, Missel A, Terbrueggen B, Zenhausern F, Rothkamm K, Meineke V, Braselmann H, Beinke C, Abend M. (2013). Laboratory Intercomparison of Gene Expression Assays. Radiation Research, 180(2), 138-148.
2. Brengues, M., Liu, D., Korn, R., & Zenhausern, F. (2014). Method for validating radiobiological samples using a linear accelerator. EPJ Techniques and Instrumentation EPJ Techn Instrum, 1(1).
3. Garty, G., Karam, A., & Brenner, D. J. (2011). Infrastructure to support ultra high throughput biodosimetry screening after a radiological event. International Journal of Radiation Biology, 87(8), 754-765.
4. Mt(Ascp), V. B., & Cohen, P. R. (2003). The Evolution of Evacuated Blood Collection Tubes ©2003 BD. Laboratory Medicine, 34(4), 304-310.
5. Rozak, P., Weegman, B., Avgoustiniatos, E., Wilson, J., Welch, D., Hering, B., & Papas, K. (2008). Devices and Methods for Maintenance of Temperature and Pressure During Islet Shipment. Transplantation Proceedings, 40(2), 407-410.  
6. Zimmerman JC. (2011). Single-use Lancet and Capillary Loading Mechanism for Complete Blood Count Point of Care Device. Cambridge, MA: Massachusetts Institute of Technology.
7. Zimmermann, M., Hunziker, P., & Delamarche, E. (2008). Valves for autonomous capillary systems. Microfluidics and Nanofluidics Microfluid Nanofluid, 5(3), 395-402.