Production of biodegradable polymers: Polyhydroxyalkanoates Part 2 Dr. Ipsita Roy School of Life Sciences University of Westminster, London, UK

Production of 3D-scaffolds using P(3HB)/Bioglass® composites

Applications of the PHA produced in hard tissue engineering : production of PHA/Bioglass®/CNT scaffolds P(3HB) P(3HB)/Bioglass® 40wt% P(3HB)/CNT 2wt% P(3HB)/CNT 4wt% P(3HB)/CNT 7wt% P(3HB)/Bioglass® 20wt%/CNT 8wt%

Electrical Properties of PHA/Bioglass®/CNT scaffolds Four-point current-voltage measurements on P(3HB) and P(3HB)-based composites Graph showing the decrease in electrical resistance as a function of carbon nanotube content. S.K.Misra et al., 2007 Nanotechnology 18(7) doi:10.1088/0957-4484/18/7/075701

Acellular bioactivity of PHA/Bioglass®/CNT scaffolds HA peaks SEM micrograph of the composite showing the formation of hydroxyapatite on the surface of the composite after two months of immersion in SBF XRD patterns of (a) P(3HB) (b) P(3HB)/Bioglass®/CNT composite (c) P(3HB)/Bioglass®/CNT composite immersed in SBF for two months, showing the emergence of hydroxyapatite peaks marked by the arrow and the indicators. S.K.Misra et al., 2007 Nanotechnology 18(7) doi:10.1088/0957-4484/18/7/075701

Cellular bioactivity of PHA/Bioglass®/CNT scaffolds

Drug delivery

Application of the bacterial PHAs in drug delivery SEM image P(3HB) microspheres Particle size distribution analysis

Application of the bacterial PHAs in drug delivery TEM images of the cross section of P(3HB) microsphere

Drug delivery via P(3HB) microsphere coated Bioglass® scaffold Microspheres loaded with gentamycin

Bioactivity measurements of the P(3HB)microsphere coated composite scaffold Evidence of hydroxyapatite formation XRD analysis

Surface roughness of the P(3HB)microsphere coated composite scaffold in SBF White light interferometry (Zygo®) data

Gentamycin release from P(3HB) microspheres 20 40 60 80 100 120 5 10 15 25 Time in hours Cumulative gentamycin release %

Gentamycin release from uncoated Bioglass® scaffolds 10 20 30 40 50 60 70 80 90 100 150 200 250 300 Time in hours Cumulative gentamycin release %

Gentamycin release from P(3HB)microsphere coated composite scaffolds 20 40 60 80 100 120 200 400 600 800 Time in hours Cumulative gentamycin release %

Comparison of Gentamycin release kinetics 20 40 60 80 100 120 200 300 400 500 600 700 800 Time in hours Cumulative gentamicin release %

Wound healing

Compressed film of Tetracycline containing P(3HB) microspheres SEM of the surface and cross section of the films

Cell viability on the P(3HB) microsphere films containing tetracycline using keratinocytes (HaCaT cell line)

HaCaT cell attachment on tetracycline loaded P(3HB) microsphere films

P(3HO)/nanobioglass solvent cast film for wound healing applications

Cell viability on the P(3HO)/nanobioglass films using keratinocytes(HaCaT cell line)

HaCaT cell attachment on P(3HO)/ nanoBioglass films

Conclusions Polyhydroxyalkanoates (PHAs) are a new emerging class of biodegradable and biocompatible polymers of natural origin. PHAs are currently being produced using Gram negative bacteria. We have pioneered the use of Gram positive bacteria, especially, Bacillus sp for the production of SCL-PHAs. Bacillus cereus SPV, a newly characterised strain of Bacillus, has been successfully used for the production of SCL-PHAs and in large scale. Cheap carbon sources have also been explored. Psuedomonas mendocina, a relatively unexplored bacteria has been successfully used for the production of a range of MCL-PHAs and in large scale The SCL-PHAs produced have been used in hard tissue engineering, drug delivery and wound healing The MCL-PHAs produced have been used in wound healing

Key workers: Dr.S.P.Valappil (polymer production from Bacillus cereus SPV) Ms Ranjana Rai (polymer production from Pseudomonas mendocina and its applications in wound healing) Mr. Akarayonye Everest (polymer production from Bacillus cereus SPV) Ms Lydia Francis (drug delivery work and wound healing) Mr. Mikey Cheng (drug delivery work) Mr. Superb Misra (the composite work using Bioglass® for hard tissue engineering) Current Collaborators: Professor A. Boccaccini, Imperial College London, UK; University of Erlangen-Neurenberg, Germany Professor R. Silva, University of Surrey, UK Professor J. Knowles, University College London, UK Professor T. Keshavarz, University of Westminster, UK

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