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Polymer Chemistry and Biomaterials Group
Hi Your Formula followers,
I am glad to announce that the PBM group (Polymer Chemistry and Biomaterials Group) is currently preparing a “scientific” treat for all of you. Geert-Jan Graulus wrote our first contribution entitled “Hydrogels, from nappies to artificial implants”. As his post was highly appreciated, PBM will elaborate further on this through a series of similar posts entitled: “Polymers. From … , to ….”.
A contribution by Elena Diana Giol from PBM research group
From the garden to your body… the fascinating world of polymers
The planned series – to appear in due course – will enable you to discover the fascinating world of polymers. You will find out how a polymer can be used to produce everyday items and in addition, how specific biomedical applications can be targeted at the same time by developing, for example, implants.
You don’t believe this is possible?
In that case, here’s just one example to convince you. Polypropylene is a polymer from which garden hoses and underground pipes are manufactured. However, the same polymer is also applied for the production of heart patches and joint prosthesis. Actually, a lot of common materials surrounding us are often used for medical applications as well. During the planned series, several materials including poly (ethylene terephthalate) (PET), poly(ε-caprolactone) (PCL), poly(methyl methacrylate) (PMMA) and many others will be tackled. We will move from plastic beverage bottles fabrication to by-pass development (see artificial veins) or from Plexiglas fabrication to encapsulation of implantable sensors for in vivo glucose detection.
The transition from regular household or everyday products to high quality implantable materials or devices is not straightforward and requires some polymer modifications to tune the final material properties. Often, the surface properties are altered while the polymer bulk properties are maintained. In general, the polymers which are transferred from a conventional purpose to a ‘niche-like’ application (e.g. implants) are characterised by at least one attractive bulk property (e.g. high thermal stability or inertness, a fast degradation, processing potential towards complex structures/geometries, etc.).
PET: the versatile polymer
PET, for example, is a polymer that is thermally and mechanically stable. These bulk properties enable its processing under harsh (i.e. extrusion- or injection-based processing methods) conditions, which are ideal to produce thousands of beverage bottles per hour. Interestingly, the same polymer is also used for a number of biomedical applications. For example, artificial veins or medical tubing are often produced from PET, yet a surface modification is typically applied prior to its application. When targeting medical applications, the material biocompatibility is an important prerequisite.First, an implant has to be ‘accepted’ by the human body before it can fulfil its function.
Often, biocompatibility is translated into the presence of suitable surface properties, as an implant interacts with the human body through its surface. In addition, medical devices present a high interdependence between the materials from which a device is manufactured, their geometrical shape and the implant performance. In addition to the surface properties which assist in the in vivo integration of an implant, both the bulk properties as well as the processing techniques applied are of high importance when targeting biomedical applications.
More, much more to come…
We propose to you a series of stories on polymers, which will be posted in due course. Each story will describe the general polymer properties, together with their transition from everyday application towards highly specialised biomedical purposes. In addition, polymer processing techniques will also be briefly presented.
DO NOT MISS OUT ON THIS EXTRAORDINARY EXPERIENCE AND TUNE IN FOR OUR FIRST STORY ENTITLED ‘PET. FROM PLASTIC BOTTLES, TO BY-PASS VEINS’!
P.S. Just to give you a grasp on polymer science, here are some basics about polymers:
Polymers. Polymers are formed by repeating one unit (a so-called monomer) multiple times. [Notice the suffixes in ‘polymer’ and ‘monomer’, derived from Greek. "Poly" can be translated as multiple or more, while "mono" means one.]
Polymer properties. Properties can be subdivided into bulk properties and surface properties. Bulk properties define characteristics that include the overall material volume (e.g. mechanical and thermal properties), while surface properties refer to the characteristics of the material top surface (e.g. wettability). Surface properties are the properties characteristic for the outer surface layer, generally ranging between several nanometres to several micrometres.
Polymer modification. Polymer modification generally refers to the modification of the polymer properties. Hence, surface or bulk modification implies that the corresponding property is affected.
Polymer processing. Polymers can be obtained as powders, liquids or resins (very viscous liquids). The commercially available end-product is obtained by further processing the polymer. Industrial processing results in the production of films, sheets, rods or specific shapes, such as cylinders or cubes which can be filled or are hollow, etc.