Page 30 - manuscript_ijb05580

3.4. Biological Performance of Osteoarthritis Model

In recent times, 3D bioprinting technology has garnered enormous attention to fabricate the

56
engineered living systems for better health . By applying this innovative technology, we are

intended to fabricate the microarchitectures-based hierarchical osteochondral model, mimicking

the osteochondral microenvironment in vivo. The 3D model was successfully constructed by using

the composite of GelMA hydrogel with C-MT or EO-MT as the bioink (Figure 8A). GelMA was

selected as it provides a bionic interface for cartilage and bone tissue, facilitating the transportation

of nutrients due to the porosity of hydrogel networks. The 3D model was completely immersed in

the medium for continuous culture, and then LPS was added for stimulation to construct the OA

model. Dic, Dex and Cur was selected for drug screening, and the production and improvement of

inflammation were verified by detecting the levels of anti-inflammatory and pro-inflammatory

factors (Figure 9A).

To elucidate the drug screening efficacy of the designed 3D osteochondral model, herein, we

further induced the LPS-assisted inflammation to the pre-designed 3D chondrocyte model in vitro.

LPS, a component of the bacteria membrane, has been extensively used to establish an

inflammatory model as it stimulates the release of inflammatory cytokines, including interleukin

57
(IL)-8, IL-6, and IL-1β . The in vitro chondrocyte model of LPS-induced inflammatory injury has

been widely reported, showing that the LPS treatment could promote the production of IL-1β and

TNF-α in chondrocyte cell 58-60 . First, no significant effect on cell viability was detected even when

the concentration of LPS reached 1 μg/mL (Figure S5). The next step involved the utilization of

LPS to induce the secretion of proinflammatory cytokines IL-1β and TNF-α in the OA model for a

duration exceeding 48 h Subsequently, ELISA was employed to measure the levels of LPS-induced

IL-1β and TNF-α in the supernatant of the biomimetic osteochondral model (Figure S6). The LPS

29