Biomaterials physical behavior

Table II. Major Tests of Physical Behavior of Biomaterials...

Journal of Biomedical Materials Research Part A. Hoboken, NJ Wiley Interscience. ISSN 0021-9304. International, interdisciplinary focus with original contributions concerning studies of the preparation, performance, and evaluation of biomaterials the chemical, physical, toxicological, and mechanical behavior of materials in physiological environments and the response of blood and tissues to biomaterials. Peer-reviewed. 

Biomedical materials include metals, ceramics, natural polymers (biopolymers), and synthetic polymers of simple or complex chemical and/or physical structure. This volume addresses, to a large measure, fundamental research on phenomena related to the use of synthetic polymers as blood-compatible biomaterials. Relevant research stems from major efforts to investigate clotting phenomena related to the response of blood in contact with polymeric surfaces, and to develop systems with nonthrombogenic behavior in short- and long-term applications. These systems can be used as implants or replacements, and they include artificial hearts, lung oxygenators, hemodialysis systems, artificial blood vessels, artificial pancreas, catheters, etc. 

The three main classes of material from which we can select for a load-bearing application are metals, polymers, and ceramics. Table 35.2 is a comparative list of the significant physical properties of different biomaterials from each of the three classical material classes. Table 35.3 compares the behavior of these different classes relevant to their potential use as implants. 

Grafts of poly(NIPAAm) have also been used to impart temperature responsive behavior to natural biomaterials for drug delivery, converting them into physically crosslinking hydrogels above the LCST of the poly(NIPAAm) portions. For example, poly(NIPAAm) grafted onto hyaluronic acid formed a gel upon injection which had a 12-hour burst release of riboflavin followed by sustained release (Ha et al. 2006). Similarly, chitosan with grafted poly(NIPAAm) was shown to release 5-fluorouracil at a controlled rate (J.W. Bae et al. 2006). 

It is hoped that the Handbook will be used and useful, not perfect but a valuable contribution to a field that we believe has matured sufficiently to merit such a publication. The Handbook is divided into synthetic and natural materials and the treatment is different in each part. More background was felt to be needed for the synthetic materials since processing and structural variations have a profound effect on properties and performance. Biological performance of these materials depends on a range of chemical, physical and engineering properties and the physical form can also influence in vivo behavior. We have not attempted to deal with issues of biological performance, or biocompatibility, but have dealt with those other features of the materials which were felt to be relevant to them as potential biomaterials. Only materials having apparent clinical applications have been included. 

The role of material surface features in biomaterial design is significant but poorly understood. Spatial control of cellular adhesion and growth is critically important in tissue engineering and related fields (1-4). Metals and plastics that are widely used for medical implants lack the molecular sequence and patterns crucial for normal cell function, and therefore often trigger aberrant cell responses in long term implantation (5). One promising approach is to introduce chemical or physical patterns on biomaterial surfaces, to achieve cell ftinctions more representative of in vivo behavior. 

Chen, J., Zhang, G., Yang, S., et al., 2011. Effects of in situ and physical mixing on mechanical and bioactive behaviors of nano hydroxyapatite-chitosan scaffolds. Journal of Biomaterials Science, Polymer Edition 22 (15), 2097-2106. 

Brandi, F., Sommer, F., Goepferich, A. Rational design of hydrogels for tissue engineering impact of physical factors on cell behavior. Biomaterials 28, 134 (2007)... 

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