1. Carl Wei He (presenter) Dr. Song Liu University of Manitoba
Narrow Sized Dual-functional Microcapsules: Contact Infection Control and Drug Delivery
Carl Wei He (presenter)
Dr. Song Liu
University of Manitoba

2. Contents Background Antimicrobial polyurea microcapsules
Concepts of Microcapsules
Applications (esp. in textiles)
Antimicrobial polyurea microcapsules
Objective: provide contact wound dressings;
Design: Feature and reasoning of the method
Details and characterizations
Shell thickness
Drug release
Contact antimicrobial property
Future research
Lead through the contents

3. What is a polyurea microcapsule?

4. Advances in polyurea microcapsules
medicine
engineering
Traditional applications
Artificial blood cells
Targeted/Triggered release
Multi- functional carrier
Electronic ink
Water treatment
Self-healing resin
Polyurea microcapsules
(PUMC)
Textiles
Agricultures

5. Application in textiles
Cosmetic textiles
Aromatherapy & Fragrance Textiles
Thermochromic & Photochromic textiles
Pest repellent textiles
Thermo regulating textiles
Flame retardant textiles

6. Objective: Antimicrobial microcapsules
Dual functions:
On-contact antimicrobial property
To provide an active shell surface
Controlled drug release property
To control the thickness of shell
Application
Chronic wound care dressing:
infection control and nutrition supply

7. Requirement for the capusles
Morphology:
controlled size and size distribution
Shell: matrix property:
Stiff enough to retain spherical shape
Thick enough to provide mass regulation
Shell: Surface property:
Easily dispersed in water for application
Contact-killing effect

8. Strategy of synthesis Interfactial crosslinking

9. IR labelling of isocyanate group

10. Strategy of synthesis functional surfactant
Modification by incorporating a multifunctional surfactant
Reduce interface tension
Provide antimicrobial functionality
Covalently bound to the matrix
Increase shell thickness
QAs

11. post-modification

12. in-situ modification

13. Comparison of two methods model capsules
Model capsules: shell thickness
Cross-section of fluorescein stained model capsules; left: post-modified model capsule; right: in-situ modified model capsule; (a)(d) freshly prepared model capsule; (b)(e)cracked model capsules after CTAC extraction; (c)(f) close-up of fluorescein stained shell

14. Quantification of QAs density of model capsules
Quantification of QAs density of model capsules. Error bar is generated from 3 batch-to-batch measurements. Control: PUMC model capsule; MCQ100: in-situ modified model capsule; MC+Q: post-modified model capsule;

15. Comparison of two methods microcapsules
Up: in-situ modified polyurea microcapsules (MCQ)
Down: control polyurea microcapsules (PUMC).
(a) MCQ dispersed in water;
(b) dry MCQ;
(c) PUMC dispersed in water;
(d) dry PUMC

16. In-vitro dissolution test
7-day in-vitro cumulative drug release profile for MCQ-Cmr; insert: first 24hr release curve; (drug load = 3.33 wt%; efficiency = 31%)

17. Antimicrobial test diffusion
(a): MCQ, Qas modified capsule;
(b): Control, Polyurea capsule without modification;
(c): Blank, last batch of washing solution of MCQ sample.
Bacteria load:
4.54 log10 cfu/cm2;
Capsule density:
0.88 mg/cm2

18. Antimicrobial test static contact
MCQ
Control
Bacteria load: 1.54 log10 cfu /cm2
Density of microcapsules mg /cm2

19. Antimicrobial test static contact
MCQ
Control
Bacteria load: 3.54 log10 cfu /cm2
Density of microcapsules mg /cm2

20. Conclusion
Isocyanate residue on polyurea microcapsules can be utilized for functionalization.
On-contact antimicrobial can be achieved on polyurea microcapsules
Sustained drug release of drug is achieved by thick shell microcapsules.
Polyurea microcapsule of narrow size distribution can be synthesized

21. Future research nanocapsules
Ease of immobolization
Larger surface for functionalization

22. Future research platform development
Platform for functionalzation
Other functional surfactants could be developted

23. Future research size control

24. Acknowledgements
Manitoba Health Research Council (MHRC) Operating and Establishment grants
Dr. Paul H.T. Thorlakson Foundation Fund
University of Manitoba Research Grant Program (URGP)
Dr. Xiaochen Gu
Dr. Lingdong Li
Dr. Rick Holley
Dr. Saqer Herzallah

25. Thank you !

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