Glutaraldehyde Treated Materials

Biolized materials have been used in our cardiac prostheses since 1969. The first application utilized glutaraldehyde treated bovine aortic valves in a Dacron fabric pump termed a "partially biolized heart". Since thick pseudoneointima (PNI) formation and calcification was observed, the Dacron covered surface was replaced with natural tissue material (9). This original totally biolized heart was a sac-type with a flexing element of natural rubber lined on the blood side with aldehyde treated bovine pericardium. The outside case of the device was made from polyurethane. Early in 1973, a calf implanted with this artificial heart lived for a then-remarkable seventeen days (10). Termination of the experiment was caused by a crack in the flexing sac. A passive implant of this device in the aorta did not show any thrombus formation during 5.5 years implantation. 

Proteins can be bonded onto substrates by chemical treatments or ionization methods such as y-ray irradiation. However, with such treatments, special attention should be paid to residues from the chemical reagents and property changes in the substrate. On the other hand, texturization by the salt casting method needs only sodium chloride, which, even if not completely removed, is not harmful biologically, and does not change the chemical or mechanical properties of the substrate. We believe that glutaraldehyde-treated gelatin on textured substrates is one of the best materials for use in blood pumps and is useful for other biomaterial applications as well. 

Table 1 Hsts representative examples of capsule shell materials used to produce commercial microcapsules along with preferred appHcations. The gelatin—gum arabic complex coacervate treated with glutaraldehyde is specified as nonedible for the intended appHcation, ie, carbonless copy paper, but it has been approved for limited consumption as a shell material for the encapsulation of selected food flavors. Shell material costs vary greatly. The cheapest acceptable shell materials capable of providing desired performance are favored, however, defining the optimal shell material for a given appHcation is not an easy task.

Fig. 17. Electron micrograph of a Chinese hamster fibroblast in prophase. Portions of two chromosomes enclosed within the nuclear envelope are shown in one the two sister kinetochores I ki/ "k2") are visible note their "back-to-back" arrangement. X60,000. The material was not treated with colcemid Icf. Brinkley and Stubblefield, 1966) glutaraldehyde fixation, post-fixed in 0s04, uranyl and lead staining. (Unpublished micrograph courtesy of B. R. Brinkley.)...

The third approach is in the implantation of functional tissue that is developed ex vivo. This approach attempts to create a biological substitute made from synthetic materials to be used as grafts or cardiac patches for treating HF. Clinically used materials include synthetic woven Dacron, extended polytetrafluoroethylene (ePTFE), and natural glutaraldehyde-fixed pericardium. These materials, however, have limited success rates due to thrombosis, inflammatory response, mechanical mismatch between native tissue and implants, aneurysm, and lack of remodeling for natural materials. ... 

Several studies have shown that microbial cellulose can be molded into tubular form with diameter < 6 mm. Klemm et al. [101] prepared a microbial cellulose tube having 1 mm diameter and 5 mm length with a wall thickness of 0.7 mm. The tensile strength of the material was foxmd to be comparable to that of normal blood vessels (800 mN) and is employed as blood vessel to replace part of the carotid artery. Alter four weeks, the microbial cellulose/carotid artery complex was covered with connective tissue. The in-vivo bicompatibility tests show that microbial cellulose can be used as a replacement blood vessel. Recently, Brown et al [102] have prepared small tubes of microbial cellulose-fibrin composites treated with glutaraldehyde in order to crosslink the polymers and allow a better match of the mechanical properties with those of native small-diameter blood vessels. 

Three different biological materials, namely, albumin (3-27%), gelatin 3-14%), and heparin (3-18%) were mixed singly or in combination in natural rubber. After adding the biological components, these surfaces were treated in one of four ways 1) 4-10% formaldehyde solution 2) heated at 90°C 3) 0.5-2% glutaraldehyde solution and 4) combination of the above methods. 

Natural tissue was treated in the same way as we treated the natural rubber material. Glutaraldehyde (0.5%) preserved or formaldehyde (4%) preserved natural tissue showed improved thromboresistance (7). The bovine aorta and pericardium were treated in the aldehyde solution for at least one week at room temperature. Afterward all the materials to be tested were soaked in physiologic saline solution... 

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