Biomaterials

Biomaterials play an important role in many different biomedical applications. Generally speaking, biomaterials encompass substances that fulfill specific functions in the human body as a replacement for damaged or lost tissues and organs. Examples of biomaterials include certain metals that can be used for the manufacture of artificial joints to replace damaged hips or knees. Other metallic biomaterials, such as nails or platens that are used in orthopedic surgery, are intended for short term application. They have to be removed after successful healing of defects, which is their main disadvantage. To circumvent this issue, a research quest for alternative biodegradable materials began in the 1970s. New materials were created that release only non-toxic products which are then elimated from the patient’s body. This group of biomaterials is mainly comprised of synthetic polymers; they have been used for degradable sutures and for implantable depot formulations of various therapeutics [1,2].

Figure: (A) Electron microscopic picture of a porous cell carrier manufactured from PEG-b-PLA. (B) Development of blood vessels in biomimetic PEG-b-PLA scaffolds functionalized with bFGF.

To this end, many different degradable polymers has been developed, stemming primarily from polymer classes such as poly(α-hydroxy esters), poly(β-hydroxy esters), polyanhydrides, and poly(cyanoacrylates). All of them can be developed as water-soluble or water-insoluble polymers, depending on the intended application [3]. The removal of these biodegradable materials from the application site and the elimination from the patient is dependent on hydrolysis, providing an ideal tool to control the implant residence time through modulation of the onset of erosion [4].

Research at the Department of Pharmaceutical Technology is focused on the design and synthesis of new polymers for many different applications ranging from medical devices to biodegradable polymer scaffolfs for tissue engineering applications. Another main focus is the development of biomimetic hydrogels, which resemble the natural ECM regarding their water content and mechanical properties. Beyond this, the polymers can be utilized as carrier systems for the controlled release of drugs or as delivery vehicles to transport DNA or siRNA into cells.

References

1. Seal BL, Otero TC, Panitch A. Polymeric biomaterials for tissue and organ regeneration. Materials Science and Engineering: R: Reports 2001; 34(4-5):147–230. doi:10.1016/S0927-796X(01)00035-3.
2. Langer R, Peppas NA. Advances in biomaterials, drug delivery, and bionanotechnology. AIChE J 2003; 49(12):2990–3006. doi:10.1002/aic.690491202.
3. Teßmar JK, Göpferich AM. Customized PEG-derived copolymers for tissue-engineering applications. Macromol Biosci 2007; 7(1):23–39. doi:10.1002/mabi.200600096.
4. Göpferich AM. Mechanisms of polymer degradation and erosion. Biomaterials 1996; 17(2):103–14. doi:10.1016/0142-9612(96)85755-3.