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Graphene oxide accelerates degradation of poly-l-lactic acid scaffold
promoted the hydrophilic properties of the scaffold of PLLA to deflect toward the interface, promoting it
is demonstrated in Figure 2. Good hydrophilicity be attacked by water molecules, thus accelerating the
facilitated liquid intrusion into the scaffold. This degradation of PLLA. This process was described
process was described as a and represented by the as a and was represented by the purple line.
1
3
red line. Second, GO was a sheet-like structure with
a large surface area and could form many interfaces 3.5 Mechanical property
with the PLLA matrix in the scaffold. These The compressive properties of samples containing
interfaces could be regarded as microchannels. On different proportions of GO are presented in
the one hand, the solution could enter the inside Figure 5A and B. The compressive strength of
of the scaffold through the interface channels to PLLA was 23.60 MPa, which was consistent with
promote the hydrolysis of ester bonds of the PLLA. the report of Zhang . The compressive strength
[52]
On the other hand, these small molecule products was 37.51 MPa and increased by 58.9% when 0.3%
produced by hydrolysis of the ester bond could also GO was introduced. As the GO content continued
be discharged through the interface channels. This to increase, the compressive strength gradually
process was described as a and was represented increased and reached a peak of 56.19 MPa when
2
by the green line. Third, the oxygen-containing 0.9% GO was introduced. Nevertheless, when the
functional groups on the surface of GO could form content of GO increased from 0.9 wt% to 1.2 wt%,
hydrogen bond interaction with the ester bond of the compression strength of scaffolds decreased
PLLA . This interaction can induce the ester bond slightly from 56.19 MPa to 54.74 MPa. Similarly,
[51]
A C D

E F

B

G H

Figure 5. (A) Compressive strength and (B) compressive modulus of PLLA and PLLA/GO scaffolds
with 0.3%, 0.6%, 0.9%, and 1.2 wt% GO. (C-G) Surface dispersion state of GO in PLLA substrate
with 0%, 0.3%, 0.6%, 0.9%, and 1.2 wt% GO. (H) Linescan 1 showed the distribution of elements C
and O. The compressive strength and modulus increased with increasing GO content, while there was
a slight decrease when 1.2% GO was introduced. GO was uniformly dispersed in the PLLA matrix, but
agglomerates formed when the GO content was further increased.

98 International Journal of Bioprinting (2020)–Volume 6, Issue 1