Precise Structural Regulation of Poly(L-lactide) Acid Tissue Engineering Scaffolds†

doi:10.7503/cjcu20150231

Abstract

Abstract:

A thermal induced phase separation combined sugar template method was used to fabricate the poly(L-lactide) acid(PLLA) scaffolds with a highly controllable inner spatial structure including pore size, inner connectivity and porosity. Scanning electron microscope(SEM), Fourier transform infrared spectroscopy(FTIR) and differential scanning calorimetry(DSC) were used to investigate the spatial structure and property of the PLLA scaffolds. The scaffolds obtained consist of adjustable micro-pores with diameter ranging from 50 μm to 800 μm and inner pore diameter ranging from 10 μm to 200 μm. Different micro- and nano-structures were formed by different solvent systems. The chemical structure of scaffold was little affected by the fabrication method. The crystallinity degree decreased on different levers after phase separation.

Key words: Poly(L-lactide) acid tissue engineering scaffold, Sugar sphere template, Thermal induced phase separation

CLC Number:

O631.2

TrendMD:

XUE Li, NIE Taotao, MA Haiyun. Precise Structural Regulation of Poly(L-lactide) Acid Tissue Engineering Scaffolds^†[J]. Chem. J. Chinese Universities, 2015, 36(7): 1409.

Figures/Tables 9

Fig.1 SEM images of sugar spheres with varying sizes(A) D-Fructose as received; (B) 50—100 μm; (C) 100—150 μm; (D) 150—200 μm; (E) 200—250 μm;(F) 250—300 μm; (G) 300—400 μm; (H) 400—500 μm; (I) 500—600 μm; (J) 600—800 μm.

Fig.2 SEM images of sugar sphere templates of different sizes with proper bonding degrees after different heat treatment time at 37 ℃(A) 50—100 μm(5 min); (B) 100—150 μm(5 min); (C) 150—200 μm(10 min); (D) 200—250 μm(10 min); (E) 250—300 μm(10 min); (F) 300—400 μm(15 min); (G) 400—500 μm(15 min); (H) 500—600 μm(20 min); (I) 600—800 μm(30 min).

Fig.3 SEM images of sugar sphere templates with different heat treatment time at 37 ℃(A, C, E, G) and PLLA scaffold with varying interpore opening size of 500—600 μm(B, D, F, H)(A, B) Without heat treatment; (C, D) heat treatment: 10 min; (E, F) heat treatment: 20 min; (G, H) heat treatment: 30 min.

Fig.4 SEM images of PLLA scaffold with varying similar macroporous structure with proper heat treatment time(A) 50—100 μm(5 min); (B) 100—150 μm(5 min); (C) 150—200 μm(10 min); (D) 200—250 μm(10 min); (E) 250—300 μm(10 min); (F) 300—400 μm(15 min); (G) 400—500 μm(15 min); (H) 500—600 μm(20 min); (I) 600—800 μm(30 min). Insets are enlarged images.

Table 1 Structural properties of PLLA scaffold with varying macroporous structure

Poresize/ μm	Heat treatment time/ min	10² Density/ (g·cm^-3)	Porosity (%)	Average pore size/ μm	Average interpore opening size/ μm
600—800	30	3.4	97.3	731.3	268.9
500—600	30	3.6	97.1	531.2	197.8
500—600	20	4.1	96.7	575.0	161.8
500—600	10	4.6	96.3	570.1	87.9
500—600	0	5.5	95.6	572.3	16.1
400—500	15	4.6	96.3	453.8	145.6
300—400	15	4.8	96.1	387.5	128.3
250—300	10	4.9	96.0	258.3	65.4
200—250	10	4.7	96.3	216.7	77.1
150—200	10	7.3	94.2	157.9	49.7
100—150	5	10.6	91.5	102.5	27.1
50—100	5	10.8	91.4	59.1	17.1

Fig.5 SEM images of PLLA scaffolds made from different PLLA solution(pore size: 500—600 μm)(A) THF; (B) CH2Cl2. Insets are enlarged images.

Fig.6 FTIR spectra of PLLA(a) and PLLA scaffold made from different PLLA solution(b—d)b. THF; c. dichloromethane; d. dioxane.

Fig.7 DSC curves of PLLA(a) and PLLA scaffold made from different PLLA solution(b—d)b. Dioxane; c. dichloromethane; d. THF.

Table 2 Thermal stastics of PLLA and PLLA scaffold made from different PLLA solution

Sample	T_m/℃	ΔH_m/(J·g^-1)	χ_c(%)	Specific surface area/(m²·g^-1)
Non-treated PLLA	178.5	63.9	68.3
THF treated	180.2	60.1	64.2	10.2
Dichloromethane treated	176.7	62.2	66.3	0.5
Dioxane treated	179.8	33.6	35.8	20.4

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