Interaction blood-biomaterial

Dr. Thomas Chandy is a research associate in the Division of Chemical Engineering Material Sciences, Biomedical Engineering Institute and Interventional Cardiology Laboratories at the University of Minnesota. He has over two decades research experience at Sri Chlia Tvunal Institute for Medical Sciences Technology, Trivandrum, India, in the area of biomaterial surface engineering and blood biomaterial interactions. More recently. Dr. Chandy and Dr. Rao have focused their research on platelet biomaterial interactiorrs and development of assist devices for cardiovascular applications. They continue to be active in this newly evolving area of research. 

Methodologies to evaluate the interaction of biomaterials with blood and blood components vary from in vitro systems, where anticoagulated blood or blood fractions are contacted with surfaces in a variety of configurations, to in vivo procedures, where tubes, sheets, etc. are inserted into the vascular system. A compendium of these techniques that seek to understand the complex interactions of blood with surfaces recently was assembled (1). 

In contrast, no anticoagulants were used in our experiments. Dif-fusional phenomena probably did not play a controlling role when the entire coagulation system was active, and biochemical and kinetic factors most likely dominated the long-term interaction between biomaterial and blood. In ex vivo experiments using a baboon model, Harker et al. (8) also found that... 

Finally, based on results from the present work, if studies of protein adsorption are to be meaningful in terms of blood-biomaterial interactions, then they should be carried out in the presence of red blood cells. 

Hoffman, AS. Blood-biomaterial interactions - an overview. Advances in Chemistry Series Nol 99, American Chemical Society Washington, DC. 1982 p.3. 

Dee KC, Puleo DA, Bizios R (2002) Blood-biomaterial interaction and coagulation. In Wiley J (ed) An introduction to tissue-biomateiial interactions. WQey, New York, pp 37-87 Defoirdt T, Boon N, Sorgeloos P, Verstraete W, Bossier P 2009) Short-chmn fatty acids and poly-/3-hydroxyalkanoates (new) biocontrol agents for a susteiinable animal production. Biotechnol Adv 27 680-685... 

Hanson, S.R. and Harker, L.A., Blood coagulation and blood-materials interactions, in Biomaterials Science An Introduction to Materials in Medicine, Ratner, B.D., Hoffman, A.S., Schoen, F.J., and Lemons, J.E., Eds., Academic Press, San Diego, 1996, pp. 193-199. 

This is an edited volume containing 23 chapters. Three chapters deal with biomaterials in general, 6 chapters address specific blood and tissue interactions with biomaterials, 10 chapters address the use of biomaterials in specific surgical disciplines, and 3 chapters address tissue engineering and genetic manipulation of cells. The reference list for each chapter is extensive. This is an excellent overview of how biomaterials interact with the host and the specific use of biomaterials in indicated applications. 

The sequence of reactions which take place by the activation of the coagulation system at the blood/biomaterial interface are summarized in Fig. 3. The competitive adsorption behavior of proteins at the biomaterial surface determines the pathway and the extent of intrinsic coagulation and adhesion of platelets. Predictions about the interactions between the biomaterial surface and the adsorbed proteins can only be formulated by having an exact knowledge of the structure of the biomaterial s surface and the conformation of the adsorbed proteins. These interactions are determined both by the hydrophobic/hydrophilic, charged/uncharged, and polar/non-polar parts of the proteins and the nature of the polymer surface [25-27]. A commonly accepted fact is that decreasing sur-... 

Interfacial blood—biomaterial interactions some conventional wisdom and some unresolved hypotheses (adapted partly from Hoffman, 1982 Vroman, 1977 NHLB1 Guidelines 1980) ... 

Blood-biomaterial interactions, provisional matrix formation, acute and chronic inflammation, granulation tissue development, foreign body reaction, and fibrosis/ fibrous capsule development comprise the series of host reactions occurring after device implantation (Fig. 4.3b) [3]. 

Although red blood cells (erythrocytes) play only a minimal role in wound healing and blood-biomaterial interactions, the contact of red blood cells with the material can lead to hemolysis. Hemolysis is the breakage of the erythrocyte s membrane with the release of intracellular hemoglobin. Normally, red blood cells live for 110-120 days. After that, they naturally break down and are removed from the circulation by the spleen. Some diseases and medical devices cause red blood cells to break too soon requiring the bone marrow to accelerate the regeneration of red blood cells (erythropoesis). Medical devices for hemodialysis, heart-lung-bypass machines or mechanical heart valves induce more hemolysis than smaller implants like stents or catheters [201]. 

Hanson, S.R., Ratner, B. Evaluation of blood-materials interactions. In Biomaterials science an introduction to materials in medicine, pp. 367-378. San Diego (2004)... 

The benefit of surface coatings has been small during CPB (see Section 78.3). In that application, blood-biomaterial interaction is limited to a few hours, and blood coagulation and inflammation... 

Surface Tension. Interfacial surface tension between fluid and filter media is considered to play a role in the adhesion of blood cells to synthetic fibers. Interfacial tension is a result of the interaction between the surface tension of the fluid and the filter media. Direct experimental evidence has shown that varying this interfacial tension influences the adhesion of blood cells to biomaterials. The viscosity of the blood product is important in the shear forces of the fluid to the attached cells viscosity of a red cell concentrate is at least 500 times that of a platelet concentrate. This has a considerable effect on the shear and flow rates through the filter. The surface stickiness plays a role in the critical shear force for detachment of adhered blood cells. 

The ratio (p/G) has the units of time and is known as the elastic time constant, te, of the material. Little information exists in the published literature on the rheomechanical parameters, p, and G for biomaterials. An exception is red blood cells for which the shear modulus of elasticity and viscosity have been measured by using micro-pipette techniques 166,68,70,72]. The shear modulus of elasticity data is usually given in units of N m and is sometimes compared with the interfacial tension of liquids. However, these properties are not the same. Interfacial tension originates from an imbalance of surface forces whereas the shear modulus of elasticity is an interaction force closely related to the slope of the force-distance plot (Fig. 3). Typical reported values of the shear modulus of elasticity and viscosity of red blood cells are 6 x 10 N m and 10 Pa s respectively 1701. Red blood cells typically have a mean length scale of the order of 7 pm, thus G is of the order of 10 N m and the elastic time constant (p/G) is of the order of 10 s. 

The suitable materials for the above mentioned domains are polymers, metals and ceramics. Among these, polymers play an important role. Even the polymers have a lot of remarkable properties that could be used in biomaterials design, the interaction between these artificial materials and tissues and blood could create serious medical problems such as clot formation, activating of platelets, and occlusion of tubes for dialysis or vascular grafts. In the last few years, novel techniques of synthesis have been used to correlate desirable chemical, physical and biological properties of biomaterials. 

Another field of application of fluorinated biomaterials is connected to lesions or evolving disease pathology of blood vessels. In particular, arteries may become unable to insure an adequate transport of the blood to organs and tissues. Polytetrafluoroethylene (PTFE) and expanded e-PTFE are the preferred materials for vascular prostheses. The interactions of blood cells and blood plasma macromolecules with both natural and artificial vessel walls are discussed in terms of the mechanical properties of the vascular conduit, the morphology, and the physical and chemical characteristics of the blood contacting surface. 

Partial or complete replacement of natural organs with prosthetic components will someday be commonplace. For instance, the design of the total artificial heart, which has had limited clinical success, involved an application of many fundamental principles already discussed as they relate to hemodynamics, biomaterials, and control. Most would agree, however, that the materials-blood-tissue interface is the nidus for some of the most serious problems preventing the development of a safe and reliable artificial heart. This reinforces the importance of investigating at the molecular level the complex interactions that occur between artificial surfaces and the physiological environment. 

Labarre, D., Vauthier, C., Chauvierre, C., Petri, B., Muller, R., and Chehimi, M. M. (2005), Interactions of blood proteins with poly(isobutylcyanoacrylate) nanoparticles decorated with a polysaccharidic brush, Biomaterials, 26(24), 5075-5084. 

A study has been carried out on the interactions of blood with plasticised poly(vinyl chloride) biomaterials in a tubular form. The influence of different factors such as the biomaterial, antithrombotic agent, blood condition and the nature of the application is represented when considering the blood response in the clinical utilisation of the plasticised PVC. The PVC was plasticised with di-(2-ethylhexyl)phthalate (DEHP) and tri-(2-ethylhexyl)trimellitate (TEHTM)and in-vitro and ex-vivo procedures used to study the biomaterial with respect to the selection of the plasticiser. The blood response was measured in terms of the measurement of fibrinogen adsorption capacity, thrombin-antithrombin III complex and the complement component C3a. X-ray photoelectron spectroscopy was used for surface characterisation of the polymers and the data obtained indicated that in comparison with DEHP-PVC, there is a higher reactivity... 

Tan, J.S. Butterfield, D.E. Voycheck, C.L. Caldwell, K.D. Li, J.T. Surface modification of nanoparticles by PEO/PPO block copolymers to minimize interactions with blood components and prolong blood circulation in rats. Biomaterials 1993,14, 823-833. 

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