Miss Anna Wilson, Dr Julian F Dye RAFT Institute Mount Vernon Hospital

1. From Secondary Intent to
Accelerated Reconstruction – the
Prospect of Dermal Scaffolds
Miss Anna Wilson, Dr Julian F Dye
RAFT Institute
Mount Vernon Hospital
Northwood Middlesex HA6 2RN
European Wound Management
Association, Copenhagen, May 2013

2. Introduction
• Current treatment of chronic wounds aimed at
optimisation of conditions for healing by secondary
intention
• Artificial skin strategies have had limited success and high
re-operation rates
• Scaffolds are becoming a promising new modality to treat
chronic wounds
• We propose use of novel scaffolds with properties to
influence cell biology of chronic wounds

3. Introduction
• A novel cross-linked fibrin-alginate porous
composite material (Smart Matrix, SM-SDR) is
proposed as a pro-vascular synthetic dermal
scaffold to:
– Increase neo-vascularisation rate
– Reduce fluid accumulation, inflammation, infection
– Improve host integration via pro-angiogenic properties of fibrin
• Can we enable conversion of chronic wound
healing to an accelerated process?

4. Smart Matrix (SM-SDR)
In Acute Wounds
• Dermal replacement
• Stabilized fibrin-derived scaffold
• Pro-angiogenic
• Rapid cellularisation
• Rapid maturation of wound site
• Rapid resorption
Clinical Applications
• Burns
• Reconstructive surgery
• Chronic wounds

5. Methods
Scaffolds were evaluated in a 4x4cm excised
and burn-excised porcine full-thickness wound
chamber model, with/without a wound ring or
split-thickness skin graft (single-step full-
thickness reconstruction)
Microperfusion was measured by laser speckle
(Moor FPLI)
Wound surface area and volume were assessed
by Eykona imaging system
Weekly wound biopsies were analysed for
contraction of scaffold and split thickness skin
graft histologically and by immunohistostaining
for ECM deposition
2. Full thickness
excision model
– single stage
reconstruction
1. Wound
chamber
model (full
thickness
excision
3. Delayed
wound model
(partially excised
burn)
3 wound models used:

6. Results
• SM-SDR demonstrated
• Deep vasculogenesis and cellular ingress within 7 days
• Completely cellularised and vascularised within 7 days
• Scaffold/tissue contraction ≤20% within 21 days
• Diminishing αSM actin positive fibroblasts and
capillaries within 21 days
• Neodermis resembling surrounding skin by:
– Palpation
– Cellular organisation – lacks obvious adnexal structures but
features consistent with regenerated tissue

7. Results: Cellularisation
Wound Chamber Model
Porcine full-thickness
wound
7 days post op
≈ 2 mm
≈ 0.4 mm
Smart Matrix
Integra
Wound bed

8. Results
Single Stage Reconstruction
1 week after single stage STSG-
Smart matrix application
2 weeks after single stage STSG-
Smart matrix application
4 weeks after single stage STSG-Smart Matrix application

9. Results
Delayed Wound Model
Delayed wound with Smart Matrix
and split thickness skin graft, day
7
Delayed wound model (control),
day 7

10. Conclusion
• Use of Smart Matrix promoted rapid
vascularisation and cellularisation for successful
single-stage full-thickness reconstruction
• Application of Smart Matrix in the chronic wound
excision model can promote wound bed to an
accelerated regenerating mode
• Future applications of Smart Matrix include repair
and reconstruction of other organs, and use as a
tissue engineering scaffold