Page 245 - IJB-10-5

International Journal of Bioprinting 3D printed hydrogels for tumor therapy

taken out, and the excess PBS on sample surface was GelMA-PDA hydrogels, hydrogel samples were irradiated
gently removed. The weight of swollen hydrogel samples by an NIR laser (wavelength: 808 nm) at different power
was measured as W . The swelling ratios of printed densities (0.5 and 1.0 W/cm ), respectively. At each
2
1
GelMA, HAp/GelMA, MgHAp/GelMA, and MgHAp/ predetermined time point, the temperatures of hydrogel
GelMA-PDA hydrogels were calculated according to the samples were recorded using an infrared camera (GUIDE
following formula: EasIR-9, AutoNavi, China).
To study the effect of NIR laser irradiation on DOX
( W − W ) release, 3D-printed MgHAp/GelMA-PDA@DOX hydrogel
Swelling ratio % () = 1 0 ×100 (III) samples were immersed in PBS and exposed to different
W 0 power densities of NIR laser (0, 0.5, and 1.0 W/cm ) for 30
2
min every 1 h at 37°C. At each predetermined time point,
where W represents the weight of dry hydrogel samples, the released medium was collected, and an equal amount of
0
and W represents the weight of swollen hydrogel samples. PBS was replenished. The amount of DOX in the released
1
To determine in vitro degradation behavior of medium was measured using a UV–vis spectrometer
3D-printed GelMA, HAp/GelMA, MgHAp/GelMA, and (UV-2600, Shimadzu, Japan) at the wavelength of 480
MgHAp/GelMA-PDA hydrogels, the weight of each dry nm. The cumulative release curves of DOX were then
hydrogel sample was weighed as M . Afterward, hydrogel established. Furthermore, to determine the pH-responsive
0
samples were immersed in 5 mL PBS supplemented with DOX release behavior of MgHAp/GelMA-PDA@DOX
0.02% sodium azide (NaN ) and placed in a shaking water hydrogels, hydrogel samples were immersed in pH 4.5
3
bath at 37°C. PBS was refreshed every 2 days. At each and pH 7.4 buffer solutions at 37°C, respectively. At
predetermined time point, hydrogel samples were taken each predetermined time point, the release medium was
out and freeze-dried. The weight of each degraded hydrogel collected, and an equal amount of fresh buffer solution was
sample was weighed as M . The in vitro degradation rate added. The amount of DOX released was measured using
1
of printed hydrogels was calculated according to the a UV–vis spectrometer at the wavelength of 480 nm. The
following formula: cumulative release curves of DOX were then established.
( M − M ) 2.7. In vitro antitumor efficiency
Degradationrate % () = 0 1 ×100 (IV) In the current study, MG63 osteosarcoma cells were
M 0 used to evaluate the antitumor efficiency of 3D-printed
MgHAp/GelMA-PDA@DOX hydrogels. MG63 cells at a
where M represents the weight of each dry hydrogel density of 1 × 10 cells per well were seeded on the hydrogel
4
0
sample, and M represents the weight of each degraded samples in a 24-well cell culture plate. Hydrogel samples
1
hydrogel sample. were cultured in the Dulbecco’s modified eagle medium
(DMEM; Gibco) supplemented with 10% v/v fetal bovine
2.5.5. pH change and ion release serum (FBS; Gibco) and 1% v/v penicillin/streptomycin
To study the pH changes of 3D-printed GelMA, HAp/ (Gibco) in a CO incubator at 37°C. Hydrogel samples
2
GelMA, MgHAp/GelMA, and MgHAp/GelMA-PDA were irradiated with an 808 nm NIR laser for 5 min every
hydrogels, 0.5 g hydrogel samples were immersed in 5 mL day. After culturing for 4 and 24 h, a live/dead assay
PBS in a shaking water bath at 37°C. At each predetermined (Invitrogen, Thermo Fisher Scientific) was employed
time point, pH value of the immersion liquid was detected to determine the survival rate of MG63 cells cultured
using a pH meter. Additionally, to investigate ion release on the hydrogel samples. Moreover, the cell viability of
behavior of printed hydrogels, 0.5 g hydrogel samples MG63 cells on the hydrogel samples was assessed using
were immersed in 5 mL PBS in a shaking water bath at 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyl tetrazolium
37°C. At each predetermined time point, 0.5 mL PBS was bromide (MTT; Invitrogen, Thermo Fisher Scientific) tests
removed and another fresh 0.5 mL PBS was added. The at each predetermined time point (1, 3, and 5 days).
concentration of Mg and Ca in PBS was determined
2+
2+
using an inductively coupled plasma mass spectrometer 2.8. Proliferation and osteogenic differentiation of
(ICP-MS, ELAN DRC-e, PerkinElmer, USA). rBMSCs on 3D-printed scaffolds
The proliferation behavior of rBMSCs on 3D-printed
2.6. Photothermal effect and in vitro DOX MgHAp/GelMA-PDA hydrogels was studied through
release behavior MTT tests. Briefly, rBMSCs at a density of 1 × 10 cells
4
To investigate the photothermal effect of 3D-printed per well were seeded on hydrogel samples in a 24-well cell
GelMA, HAp/GelMA, MgHAp/GelMA, and MgHAp/ culture plate and cultured in medium in a CO incubator at
2

Volume 10 Issue 5 (2024) 237 doi: 10.36922/ijb.3526