Page 470 - IJB-9-5

International Journal of Bioprinting 3D printed hydrogel for infected wound healing via PDT

Table 1. Parameter of MB@UiO-66(Ce)/PH samples
Sample SF Gelatin RPS SPS MB@UiO-66(Ce)
name (mg/mL) (mg/mL) (mg/mL) (mg/mL) (mg/mL)
PH-0 30 50 0.013 2.382 0
PH-0.1 30 50 0.013 2.382 0.01
PH-0.5 30 50 0.013 2.382 0.05
PH-1 30 50 0.013 2.382 0.1
Abbreviations: SF, silk fibroin; RPS, riboflavin; SPS, sodium persulfate.

MB@UiO-66(Ce) composite SF/gelatin 3D-bioprinted using N,N-dimethylformamide and soaking in ethanol for
photo-crosslinked hydrogel system was developed to 48 h at 60°C. Finally, the MB@UiO-66(Ce) product was
promote soft tissue regeneration in the infected area. obtained by vacuum-drying overnight at 60°C.

2. Materials and methods 2.4. MB@UiO-66(Ce) characterization
The morphology of the obtained MB@UiO-66(Ce) was
2.1. Materials observed by transmission electron microscopy (TEM; FEI
Bombyx mori cocoons were purchased from Jiangsu Talos L120C, Thermo Scientific, USA). The samples were
Province, China. Type A gelatin, riboflavin (5’-phosphate ultrasonically dispersed in ethanol and dropped on the
sodium salt hydrate), and sodium persulfate were copper mesh.
purchased from Sigma-Aldrich, USA. LIVE/DEAD kits
were ordered from YESAN, China. Dulbecco’s Modified The particle size was measured using a particle size
Eagle Medium (DMEM) and 100 U/mL penicillin and analyzer (Nicomp Nano Z3000, PSS, USA). Samples were
streptomycin were ordered from HyClone, USA. Fetal centrifuged and dispersed in ultrapure water to create
bovine serum (FBS) was ordered from Gibco, USA. FITC- 0.5 mg/mL aqueous dispersions, which were sonicated for
phalloidin and DAPI were obtained from Invitrogen, USA. 5 min before testing.
CCK-8 assay kits were purchased from Beyotime, China.
2.5. Preparation of hydrogel materials
2.2. Preparation of silk fibroin The 50 mM RPS and 1 M SPS aqueous solutions used as
SF was extracted from Bombyx mori cocoons according stock solutions were applied to initiate the photochemical
to the following protocol . First, domestic silk moths reactions. Various concentrations of MB@UiO-66(Ce)
[29]
were subjected to boiling in a 0.5 wt% Na CO solution for were mixed in the solution of 1 mL of 30 mg/mL SF and
3
2
30 min, which was repeated three times, and then dried 50 mg/mL gelatin solution with the addition of 20 μL RPS
in an oven at 60°C. A ternary solution was prepared with and 10 μL SPS stock solutions, making 0.1%, 0.5%, and
the molar ratio of CaCl : water: ethanol = 1:8:2. The dried, 1% w/v the final concentrations of MB@UiO-66(Ce). The
2
degummed silk cocoons were then dissolved in the ternary hydrogel samples with varying concentrations of MB@
solution, followed by dialysis in deionized water for 3 days UiO-66(Ce) were designated as PH-0, PH-0.1, PH-0.5, and
(MW = 3500). Finally, the SF was obtained by freeze- PH-1, respectively. The mixtures were exposed to 460 nm
drying. light to initiate photo-crosslinking at an intensity of
1200 mW/cm for 30 s. The distance used for curing light
2
2.3. Synthesis of nanoscale MB@UiO-66(Ce) was 20 mm. The compositions of each group of composites
First, the F127@UiO-66(Ce) samples were synthesized. are detailed in Table 1. The 3D-bioprinted MB@UiO-
Briefly, F127 (112.5 mg) was dissolved in 27 mL deionized 66(Ce)/PH for further cell culture and in vivo experiments
water. Then, 2250 mg NaClO H O, 0.3375 mL acetic acid, was fabricated under sterile conditions.
4
2
and 0.675 mL HNO were added and stirred to form a
3
homogeneous mixture. Then, 616.5 mg (NH ) Ce(NO ) 2.6. 3D bioprinting
4 2
3 6
and 186.75 mg benzenedicarboxylic acid (BDC) were The BioScaffolder 3.2 (GESIM Corporation, Germany)
added to the mixture, followed by stirring for 20 min at with extrusion-based 3D-bioprinting technology was
60°C. After that, the F127@UiO-66(Ce) particles were used as a low-temperature bioprinting modality. The print
suspended in a 30-mL MB aqueous solution (0.2 mg/mL), head temperature was adjusted to 22.5°C with a speed
which was stirred for 1 h at room temperature. The of 5 mm/s, and the MB@UiO-66(Ce)/PH were printed
resultant solid was obtained by centrifugation and washed directly onto the Petri dishes. The hydrogels were printed as
three times with deionized water. F127 was eliminated by hexagons with 7-mm radius and 3-mm height. Finally, the

Volume 9 Issue 5 (2023) 462 https://doi.org/10.18063/ijb.773