At the cartilage-to-bone interface, the residing cells are different with respects to metabolic requirements. Fabrication of a scaffold affording different metabolic needs of these cells can be taken account of a promoting step for regeneration of cartilage- to-bone interface. In the present study, a scaffold with a depth-dependent gradient of oxygen releasing microparticles was developed. To this end, oxygen releasing microparticles were fabricated from polylactic acid (PLA) and calcium peroxide and then dispersed in hydrogel precursor of functionalized pectin and fibroin. The microparticles were loaded in a hydrogel precursor solution in a gradient manner using a gradient mixing chamber. The mixing chamber was composed of two compartments filled with hydrogel precursors with different microparticle contents (10 and 30% w/w) and an interfacial mixing port. The velocity of microparticle loaded solution inside the gradient chamber was modeled using momentum balance Navier–Stokes equations. Moreover, spatial and temporal variations of microparticle concentration in the gradient chamber were modeled using mass transfer Navier–Stokes equations. Chemical, morphological and structural variations across the composite thickness were evaluated using microscopy and spectroscopy analyses. The model proposed by Navier–Stokes equation corroborated that the flow velocity was different in various domains of the mixing chamber and in the vicinity of the mixing port the velocity was substantially higher than the bulk flow. Moreover, the velocity profile showed gradual velocity changes from bulk to the mixing port. The model represented for microparticle concentration proved that microparticle content of precursor solution varied both spatially and temporally. As time goes by, the microparticle concentration gradually increased from about 10 %w/w and approached to about 30% w/w at the end of the process. SEM micrographs from the cross-section of composite corroborated that microparticle density gradually increased from the lower to the upper surface. Spectroscopy confirmed that the oxygen releasing component, i.e. calcium peroxide, increased across the said direction. Oxygen measurement from successive sections of composite revealed that the amount of produced oxygen increased from the lowermost to the uppermost section. In conclusion, the hydrogel/particle composite with a gradient in oxygen releasing component can be a promising scaffold to satisfy the different metabolic needs of cells at the cartilage- to-bone interface.

在软骨与骨骼的界面上，驻留细胞的代谢要求不同。可以考虑提供这些细胞的不同代谢需求的支架，考虑到软骨-骨界面再生的促进步骤。在本研究中，开发了具有深度依赖的氧释放微粒梯度的支架。为此，由聚乳酸（PLA）和过氧化钙制备了释放氧气的微粒，然后将其分散在功能化果胶和血纤蛋白的水凝胶前体中。使用梯度混合室以梯度方式将微粒装载在水凝胶前体溶液中。混合室由两个隔室组成，两个隔室中充满了具有不同微粒含量（10和30％w / w）的水凝胶前体和一个界面混合端口。使用动量平衡Navier–Stokes方程对梯度室内的微粒加载溶液的速度进行建模。此外，使用传质Navier–Stokes方程对梯度室中微粒浓度的时空变化进行了建模。使用显微镜和光谱分析评估了整个复合材料厚度的化学，形态和结构变化。Navier-Stokes方程提出的模型证实了在混合室的各个区域中流速是不同的，并且在混合口附近，流速大大高于整体流速。此外，速度分布图显示了从体积到混合口的逐渐速度变化。以微粒浓度表示的模型证明，前体溶液的微粒含量在空间和时间上都变化。随着时间的流逝，微粒浓度从约10％w / w逐渐增加，并在过程结束时达到约30％w / w。从复合材料横截面的SEM显微照片证实，微粒密度从下表面到上表面逐渐增加。光谱证实，释放氧的成分，即过氧化钙，沿所述方向增加。从复合材料的连续部分进行的氧气测量表明，产生的氧气量从最低部分到最高部分增加。结论，