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

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

3. 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%

4. 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: / /18/7/075701

5. 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: / /18/7/075701

6. Cellular bioactivity of PHA/Bioglass®/CNT scaffolds

7. Drug delivery

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

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

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

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

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

13. Gentamycin release from P(3HB) microspheres20 40 60 80
100
120 5 10 15 25
Time in hours
Cumulative gentamycin release %

14. Gentamycin release from uncoated Bioglass® scaffolds10 20 30 40 50 60 70 80 90
100
150
200
250
300
Time in hours
Cumulative gentamycin release %

15. Gentamycin release from P(3HB)microsphere coated composite scaffolds20 40 60 80
100
120
200
400
600
800
Time in hours
Cumulative gentamycin release %

16. Comparison of Gentamycin release kinetics20 40 60 80
100
120
200
300
400
500
600
700
800
Time in hours
Cumulative gentamicin release %

17. Wound healing

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

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

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

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

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

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

24. 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

25. 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

26. My Group

27. Thanks for your attention!