Implants / implant materials 

The market for implants is highly competitive especially as far as classical implants, pacemakers, orthopedic implants and dental implants are concerned. In spite of above-average growth rates, the burgeoning number of suppliers is subject to a major price crunch. The areas below need technological enhancement: 

• bacteriostatics of polymer implants (such as catheter and infusion tubes), 
  
• preventing heart valves from calcifying, 
  
• boosting the endurance and resorption behavior of substitute bone materials, 
  
• modifying the surface to make implants integrate quickly into the surrounding tissue 
  
• integrating materials with low biocorrosivity and long term stability 
  

Some examples of future developments are intelligent stimulation electrodes in the neurons and muscles or intelligent metering implants (such as »insulin implants«). However, the problem of nervous stimulation from electrical current still has to be solved without subjecting cells to stress or electrolytic/ toxic afflictions with long-term unplants. 

All biological hard tissue such as dentin or bones are composite materials, which is the reason why it is of particular importance to devise biocompatible composites for use as implant materials. Nanotechnological surface modification can eventually be a way to completely mask these materials for the body to substantially enhance compatibility. 

Tissue engineering 

A new field for applying biocompatible ceramics and polymers has emerged in in-vitro tissue cultivation (first and foremost tissue engineering) as a physiological substitute for tissue chronically or traumatically damaged. Needs extend over virtually all forms of human tissue from the arthrotically destroyed knee joint to vital organs no longer functioning (such as infarction tissue). Autologous cells are built up in vitro, down to functioning tissue on biocompatible carrier matrices known as scaffolds. Some of the special requirements for the carrier matrix are listed below:   

• free shaping in terms of the size and distribution of indispensable interconnecting pores, 
  
• integrating growth factors, 
  
• maximum pH-neutral resorption and 
  
• installing sensor/actuator systems to stimulate and monitor cell specialization (i. e., bones) 
  

Membrane systems and drug carriers 

Biocompatible membranes are a major component in the process of manufacturing, transporting and isolating substances with their main application located in haemodialysis (also as large-surface dialysers > 1.5 m2) and extracorporeal blood oxygenation (»membrane lung«). Given the fact that 48,000 patients are dependant upon artificial blood purification in Germany alone, driving down costs for disposable cartridge systems through higher efficiency and greater innovation may turn out to be a major priority for research & development efforts in this market segment. Per person, annual costs currently range between 30,000 and 60,000 euro. 

Some of the typical non-porous materials for separating gases in general or the special medical application of blood oxygenation are cellulose acetate, silicone elastomers or polyimides. 

Another field is carriers that selectively transport pharmaceutical agents to their destinations in the organism and discharge them in a controlled fashion. Particles from biocompatible materials with diameters ranging from 10 nm to 1 µm are some of the foremost intelligent carrier systems. There is a great need for research in enhancing compatibility to sensitive matter such as proteins and peptides that can be deactivated by the developing chemical milieu (the pH-value and osmotic pressure) within decaying polymers or by adsorbing to polymer surfaces. 

Medical instruments for minimal-invasive surgery 

Classical medical technology with its instruments will undoubtedly remain a stable growth market for material sciences. What is known as »keyhole surgery« has established itself as a method of treatment throughout the world and developed on an enormous scale in the past decades. The characteristics required for minimal-invasive surgery tools are minimum volume, high hardness and outstanding cutting properties. What’s more, in operations involving blood circulation, they may not allow particles with diameters in excess of 10 µm to get into the blood stream. Microstructuring of surface-coated materials is what can prevent this. Finally, connecting techniques for biocompatible polymers would have to be devised for positioning and handling of tools and anchoring of implants. 

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