Through-thickness control of polymer bioresorption via electron beam irradiation.
Predicable and controlled degradation is not only central to the accurate delivery of bioactive agents and drugs, it also plays a vital role in key aspects of bone tissue engineering. The work addressed in this paper investigates the utilisation of e-beam irradiation in order to achieve a controlled (surface) degradation profile. This study focuses on the modification of commercially and clinically relevant materials, namely poly(L-lactic acid) (PLLA), poly(L-lactide-hydroxyapatite) (PLLA-HA), poly(L-lactide-glycolide) co-polymer (PLG) and poly(L-lactide-DL-lactide) co-polymer (PLDL). Samples were subjected to irradiation treatments using a 0.5MeV electron beam with delivered surface doses of 150 and 500 kGy. In addition, an acrylic attenuation shield was used for selected samples to control the penetration of the e-beam. E-beam irradiation induced chain scission in all polymers, as characterized by reduced molecular weights and glass transition temperatures (T(g)). Irradiation not only produced changes in the physical properties of the polymers but also had associated effects on surface erosion of the materials during hydrolytic degradation. Moreover, the extent to which both mechanical and hydrolytic degradation was observed is synonymous with the estimated penetration of the beam (as controlled by the employment of an attenuation shield).
Cairns
Marie-Louise
ML
School of Mechanical and Aerospace Engineering, Queen's University Belfast, Belfast BT9 5AH, UK. m.cairns@qub.ac.uk
Sykes
Alice
A
Dickson
Glenn R
GR
Orr
John F
JF
Farrar
David
D
Dumba
Arthur
A
Buchanan
Fraser J
FJ
D001672:Biocompatible Materials / Q000737:chemistry*; D002152:Calorimetry, Differential Scanning; D002850:Chromatography, Gel; D003460:Crystallization; D017886:Durapatite / Q000737:chemistry; D004583:Electrons; D019344:Lactic Acid / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D008970:Molecular Weight; D011091:Polyesters / Q000737:chemistry; D011098:Polyglactin 910 / Q000737:chemistry; D011108:Polymers / Q000737:chemistry*; D013314:Stress, Mechanical; D013499:Surface Properties
D001672:Biocompatible Materials; D011091:Polyesters; D011108:Polymers; C499699:hydroxyapatite-polylactide; D019344:Lactic Acid; D011098:Polyglactin 910; C033616:poly(lactide); D017886:Durapatite