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Silica microsphere-resorcinol composite embedded collagen

scaffolds impart scar-less healing of chronic infected burns in type-I

diabetic and non-diabetic rats

Kalirajan Cheirmadurai,a,b Palanisamy Thanikaivelan* a,b

aAdvanced Materials Laboratory, Central Leather Research Institute (Council of Scientific and

Industrial Research), Adyar, Chennai 600020, India.

bUniversity of Madras, Chepauk, Chennai 600005, India.

E-mail: thanik8@yahoo.com; thanik@clri.res.in

Electronic Supplementary Material (ESI) for Biomaterials Science.This journal is © The Royal Society of Chemistry 2020

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Fig. S1. 13C solid state NMR spectra of FSP and OFSP

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Fig. S2. (a) FT-IR spectra of the FSP and OFSP. (b) Magnified FT-IR spectra in the range 2000

to 600 cm-1 showing the aldehyde peak clearly.

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Fig. S3. TEM image of the pristine silica microspheres.

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Fig. S4. FT-IR spectra of the silica microsphere, resorcinol and Si@Res composite.

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Fig. S5. (a) FT-IR and (b) CD spectra of the native collagen, Coll/OFSP/Si@Res 2% and

Coll/OFSP/Si@Res 5% scaffolds.

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Fig. S6. DSC thermogram of the Coll/OFSP alone.

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Fig. S7. (a) Antioxidant activity and (b) hemolytic activity of the collagen (1),

Coll/OFSP/Si@Res 2% (2) and Coll/OFSP/Si@Res 5% (3) scaffolds.

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Fig. S8. Digital images of the rats (a) before and (b) after burn wound creation.

Fig. S9. H&E staining image of the eschar tissue collected after burn wound creation (0th day)

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Fig. S10. (a) H&E and (b) Masson’s trichrome staining of the granulation tissue collected on 8th

and 16th day of healing from the non-diabetic open wound (Non.dia.OW), native collagen

(Non.dia.Coll) and hybrid scaffold (Non.dia.Coll/OFSP/Si@Res 5%) treated animal groups. (BV

represents blood vessels, FB represents fibroblasts and ED represents epidermal layer in the

image.)

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Fig. S11. H&E images of the newly regenerated skin collected after 24 days of healing followed

by 30 days of maturation from the non-diabetic open wound (Non.dia.OW), native collagen

(Non.dia.Coll) and hybrid scaffold (Non.dia.Coll/OFSP/Si@Res 5%) treated animal groups at (a,

d and g) lower magnification to show the full skin structure and (b, e and h) higher magnification

to show the thick epidermis, respectively. In the image, BV represents blood vessels, ED

represents epidermal layer, SG represents sebaceous gland, KL represents keratinized layer and

HF represents hair follicle. (c, f and i) Masson’s trichrome staining of the regenerated skin

collected from the non-diabetic open wound (Non.dia.OW), native collagen (Non.dia.Coll) and

hybrid scaffold (Non.dia.Coll/OFSP/Si@Res 5%) treated animal groups. (j) Thickness of the

epidermis in non-diabetic unwounded skin and experimental groups. *Statistically significant, p

< 0.05 vs. non-diabetic open wound group (Non.dia.OW), #statistically significant, p < 0.05 vs.

non-diabetic collagen scaffolds treated group (Non.dia.Coll), ♦statistically significant, p < 0.05

vs. Exp. (k) Scar elevation index for all the non-diabetic experimental groups. †Statistically

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significant, p < 0.05 vs. non-diabetic open wound group (Non.dia.OW), ҂statistically significant,

p < 0.05 vs. non-diabetic collagen scaffolds treated group (Non.dia.Coll).

Fig. S12. H&E staining of the unwounded skin at (a) lower and (b) higher magnification,

respectively. (c) Masson’s trichrome staining of the unwounded skin.

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Fig. S13. CD31 immunohistochemistry staining of the newly regenerated skin collected from the

non-diabetic (a) open wound (Non.dia.OW), (b) native collagen (Non.dia.Coll) and (c) hybrid

scaffold (Non.dia.Coll/OFSP/Si@Res 5%) treated animal groups. Arrows in the images show the

blood vessels. (d) Number of blood vessels calculated from the CD31 images of the different

non-diabetic animal groups. *Statistically significant, p < 0.05 vs. non-diabetic open wound

group (Non.dia.OW), #statistically significant, p < 0.05 vs. non-diabetic collagen scaffolds

treated group (Non.dia.Coll). TGF-β3 immunohistochemistry staining of the regenerated skin

collected from the non-diabetic (e) open wound (Non.dia.OW), (f) native collagen (Non.dia.Coll)

and (g) hybrid scaffold (Non.dia.Coll/OFSP/Si@Res 5%) treated animal groups.

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Fig. S14. Enlarged TGF-β3 immunohistochemistry staining of the regenerated skin collected

from the hybrid scaffold treated (a) diabetic and (b) non-diabetic animals to show the expression

of TGF-β3 clearly.