OCTOBER 2018
Griffith University | Health Sciences / Medical Sciences / Engineering

Antony McNamee
Undergraduate Student

The Doctor of Philosophy (PhD) is Griffith's premier research training degree. Under the supervision of Dr. Michael Simmonds and Professor Geoff Tansley, graduate students are mentored to develop a theme of research inspecting erythrocyte physiology to uncover novel biochemical and physical properties of blood cells. The Mechanobiology Research Laboratory (Simmonds-Tansley Lab) has emphasis on enhancing blood compatibility with medical heart-lung machines. PhD candidates make significant and original contribution to knowledge in the biorheology and artificial organ field.

The required purpose of the Hamilton syringes will be to facilitate the micropipette aspiration (and microinjection) of red blood cells to inspect single cell biophysics and biochemistry. Thus, the products of interest are: the knurled hub 7000 series syringe with the 25 gauge needle, the luer to RN adapter (55753-01), the RN-RN coupler (55752-01), the 1 mm compression fittings ( 55750-01), and the priming kit (PRMKIT).

The Hamilton syringes will be used for micropipette aspiration and microinjection of red blood cells. Micropipette aspiration techniques are a single cell manipulation tool that has extensive biomedical application, ranging from investigations of microinjection, in vitro fertilisation, and removal of cell nuclei (i.e., denucleation). Previously, micropipette aspiration methods have been deployed to investigate the mechanical and adhesive properties of blood cells. This system can investigate single cells with submicron precision, and with the sensitivity to measure piconewton (pN) forces.

The process of micropipette aspiration involves the use of a custom-made (in-house) glass pipette with a tip radius of 0.5 micron. This miniature glass pipette is micromanipulated adjacent to a cell membrane and is used to provide suction pressure in combination with microscopic observation to determine physical and mechanical properties of the blood cell membrane. To control and regulate pressure, the glass pipette will be connected to the Hamilton products suggested for micropipette aspiration, and the syringe movement will be controlled by microfluidic syringe pumps. For determination of the shear modulus of the RBC membrane, a small portion of the cell will be aspirated into the micropipette, and the length of the membrane portion inside the pipette will be measured at several intervals of increasing pressure until a maximum membrane tensile strength is exceeded and the cell ruptures. The relationship between membrane aspiration length and increasing pressure will yield the relevant biophysical data.

With the ability to inspect the physical properties of blood cells with submicron precision, novel investigations into cell physiology can be conducted with the unique perspective of our team. As an educational tool, the constructed micropipette aspiration rig will directly provide the necessary equipment for high-end laboratory training, teaching desirable skills for subsequent student employment. As a research implement, the use of the Hamilton products will support the projects of numerous Masters and Doctorate candidates investigating the various biophysical properties of blood cell membranes. Immediately this system will directly assist one of the major projects of Mr. McNamee's PhD (and the Biorheology Research Laboratory), assessing the blood compatibility from current rotary blood pumps. This device with the use of the Hamilton products will facilitate the development of future artificial organs that are 'blood friendly' - helping patients requiring heart-lung support or hemodialysis to live longer.

The current Hamilton products are developed with the desired precision that can be used for microfluidic and micropipette applications. The products are well manufactured. For injection or cell shearing systems, an option for non-glass syringes with greater biological compatibility would be good for long periods of biological-glass syringe contact; however, for aspiration techniques, the current products are perfectly suited for the extremely small volumes that will be aspirated.

Mr. McNamee is a final year doctorate (PhD) candidate investigating the blood damage that occurs from (non)compatibility with artificial organs (such as heart-lung machines or hemodialysis). Mr. McNamee conducts his studies as a part of an international multidisciplinary team consisting of physiologists, engineers, clinicians, and mathematicians. The Griffith University Mechanobiology Laboratory and the Biorheology Research Laboratory hosts students from various programs, teaching and developing undergraduate and postgraduate students in engineering, medicine, exercise physiology, physical therapy and pharmacy/toxicology. The small dedicated Australian team at Griffith University is consistently motivated to produce high-quality research that will have resounding international impact that can translate to improved clinical outcomes (and increased patient survival). As we are a small team, any support for the development of our systems and our research themes are always put to extensive use, and are never wasted!