MatPAC Courses Offered - Penn State University
BIOMEDICAL MATERIALS
P.W.
Brown
Rm 136, Materials Research Lab. Ph: 865-5352; etx@psu.edu
Metals, polymers, and ceramics and their composites, which are capable
of emulating the functions of hard and soft tissues, are the subjects
of this course. The subject matter is confined to implanted materials;
external appliances, such as casts, braces, contact lenses, etc., are
not considered.
The topical content of this course will be grouped into 4 areas. A general introduction to selected aspects of physiology will be presented. This will provide the background necessary to appreciate the factors which govern the selection of biomedical materials. Specific emphases will be placed on the polymerization of biopolymers (polypeptides and polysaccharides) and the general relationships between conformation and biological function, the biochemistry of blood and blood- surface interactions, the formation of teeth and bone and the relationships between microstructure, composition and function, the immune responses to implanted materials, the resorption of bone (osteoporosis) and the development of caries. The perspective placed on these topics will be that of materials (that is, why is a material acceptable or not acceptable for a particular application).
The selection of ceramics for hard tissue prostheses will be described. Orthopedic and dental applications for ceramics will be discussed. Specific ceramic materials to be treated include dental porcelain, alumina- and zirconia-based ceramics, and bioactive glasses (orthopedics), and pyrolytic carbons (heart valves). Various classes of inorganic cements used in dental applications (gypsum, zinc phosphates, zinc carboxylates, silicates, and glass-ionomer cements) will also be considered as ceramics. Hydroxyapatite (HAp), HAp coatings, HAp-based composites and HAp-metal interactions will be discussed in particular. Relationships among physical properties, mechanical properties, and chemical interactions with biological fluids will be described.
Uses of metals will be described with an emphasis on orthopaedics. The fracture toughness of metals, their electrochemical responses in vivo, and the nature of the interfacial interactions with hard tissues will be treated. Metals and alloys, such as Ti, Co-Cr, and stainless steel, used in prosthetic applications will be described and their properties and limitations discussed. The phenomenon of stress shielding and the immune responses associated with the accumulation of metallic and polymeric particulate debris in the vicinity of an implant will be discussed in particular. Dental amalgams and the noble metals for dental applications may also be considered.
Polymers
are important in a broad range of biomedical applications. Among these
are blood conduits, soft tissue prostheses, hemostatic agents, dental
restoratives, bone replacement materials, and surgical adhesives. In
some applications it is desirable that a polymer biodegrade while in
others property retention is desirable. The topics related to polymers
will concentrate on hemocompatible polymers used for applications involving
blood contact, acrylics used as bone cements, polyethylene used as bearing
surfaces in prostheses. Biopolymers of natural origin (e.g. collagen)
and their uses as prostheses (heart valves) will be also discussed.
Time permitting, other polymers and their applications, such as sutures/adhesives
and dental resins and bonding materials, will be discussed.