Characterization of viscoelastic materials by rheometry to identify parameters affecting blood clot solidity
Austria (AMSA) - University of Vienna, Vienna
Center of Biomedical Research, Division: Decentralized Biomedical Facilities, Borschkegasse 8a, 1090 Vienna, Austria
Univ.-Prof. Dr. Bruno Podesser
ao. Univ.-Prof. Dr. Ursula Windberger, BSc
English, German
4 weeks
Cities/Months Jan Feb Mar Apr May Jun Jul Augt Sep Oct Nov Dec
No No No No No No Yes No No No Yes Yes
Type of Research Project
- Basic science
What is the background of the project?
We test viscoelastic matter (e.g. blood suspensions, blood clots, and technical polymer resins) and find out their elasticity and flow behavior. We perform flow curves of the materials in steady shear, and determine their response to shear stress by oscillating shear (stress/strain-dependent and time-dependent behavior of the material). We identify the yield and flow points, the stability and degree of percolation of suspensions/dispersions, the curing kinetics of polymers, and the behavior of blood clots upon applied stress in SAOS (small amplitude oscillatory) and LAOS (large amplitude oscillatory) tests.
What is the aim of the project?
To identify parameters that are crucial for the “strength” of blood clots.
What techniques and methods are used?
Rheometry (Physica MCR 301, Anton Paar, Austria) and thrombelastometry (Rotem, TEG Instr, Germany) are the major techniques we will be using for the above-described research. Student will firstly get acquainted with both devices by observing the tutors, which will provide a full explanation. Then, the student will be able to work on its own. At the end, the student will be involved in the analysis of the results he has gathered. Short information on both techniques: Rheometer is used to measure the deformation properties of liquids under stress (e.g. in flow). As mentioned, we will measure such properties in a model of blood with blood clots. Thrombobelastometry is an advanced coagulation test, with which it is possible to diagnose coagulopathy and to guide hemostatic therapies.
What is the role of the student?
- The student will observe the practical experiments but will be highly involved in the analysis of the results
- The tasks of the student will be performed on his/her own
- The tasks will be done under supervision
What are the tasks expected to be accomplished by the student?
Concentrated work on the rheometer by using the routine protocols of the lab for viscometry, SAOS tests (amplitude sweep and frequency sweep, 3-Intervall tests), data analysis of LAOS-tests. Dynamic oscillatory shear tests are performed by subjecting a material to a sinusoidal deformation and measuring the resulting mechanical response as a function of time. Oscillatory shear tests can be divided into two regimes. One regime evokes a linear viscoelastic response (small amplitude oscillatory shear, SAOS) and the other regime is defined by a measurable nonlinear material response (large amplitude oscillatory shear, LAOS). As the applied amplitude (of strain or stress) is increased from small to large at a fixed frequency, a transition between the linear and nonlinear regimes can appear.
Will there be any theoretical teaching provided (preliminary readings, lectures, courses, seminars etc)
Participation at our lab meetings and jour fixes
What is expected from the student at the end of the research exchange? What will be the general outcome of the student?
- The student will prepare a scientific report
- The student’s name will be mentioned in a future publication
What skills are required of the student? Is there any special knowledge or a certain level of studies needed?
Concentrated work in the lab. Experience in practical lab work (pipettes, etc) and understanding of the value of analytical work Subjects passed: Biomedical fields: BSc Medical Students: 2 years and less before graduation
Are there any legal limitations in the student’s involvement
No criminal conviction
Type of students accepted
This project accepts:
- Medical students
- Graduated students (less than 6 months)
- Students in biomedical fields
- Hyun K; et al. A review of nonlinear oscillatory shear tests: analysis and application of large amplitude oscillatory shear (LAOS). Progress in Polymer Science. 2011.
- Veigas PV; et al. A systematic review on the rotational thrombelastometry (ROTEM) values for the diagnosis of coagulopathy; prediction and guidance of blood transfusion and prediction of mortality in trauma patients. Scand J Trauma Resusc Emerg Med. 2016 24:144.