Category: Formulation and Quality
Purpose: Biomimetic hydrogels scaffolds combined with nanofiber (SA-Cys-dNFs-PEG) are robust in mechanical property and can serve as an ideal niche for adipose derived human mesenchymal stem cells (AD-MSCs) with immunomodulatory effects. They could provide an efficient base to regulate lipid-laden macrophages and recover the endothelium function in atherosclerosis. This cell mediated biomimetic hydrogel would plausibly minimizes the consequences of smooth migration, thus eliminating the occurrence of very late in-stent restenosis and thrombosis.
The biomimetic hydrogel has been further utilized as the novel approach of bioprinting stent (BPS) to recover endothelial functions and minimize the immune and biological risks. The aid of 3-D bio-printing technique could overcome the therapeutic difficulties and obtain the efficient customized cardiovascular stent by optimization of its structure integrity, thickness, stability, mechanical strength and biodegradation.
Methods: A mixture of dispersing-nanofibers (dNFs) and poly (ethylene glycol)-diacrylate (PEGDA) were blended with sodium alginate-cysteine (SA-cys) to prepare hydrogel scaffolds (SA-Cys-dNFs-PEG).
The effects of AD-MSCs loaded in SA-Cys-dNFs-PEG on cell viability and proliferation rates were evaluated using LDH assay and alamar blue assay, respectively.
The immunomodulatory activity of AD-MSCs as well as their influence by ROS, the level of L-Kynurenine was determined.
For 3-D bio-printing stent (BPS), structure integrity, thickness, stability, mechanical strength and biodegradation of biomimetic hydrogels combined with nanofiber were optimized.
The suitable printing concentrations of SA-Cys-PEG in the range of 1–3% with pseudo-physiological wall stresses of approximately 2-16 dyne*s/cm2. (200-1600 cPs) were tested.
One-way ANOVA was used to compare the means of independent samples and Tukey’s HSD was used for a post-hoc analysis.
As the ROS level increases, the concentration of L-kynurenine increased with a greater rate than those treated with only TNF-α (1.67±0.6 μM without H2O2, 5.2±1.14 μM with 50 μM of H2O2 and 8.8±0.51μM with 100 μM of H2O2) supporting the enhanced subcellular level of ROS by spheroidal cluster yielded IDO-mediated tryptophan replacement process.
No cytotoxicity of AD-MSCs was observed after 48 h exposure to SA-cys at the concentrations of 0–2 mg/mL and d-NFs at the concentrations of 0–0.8 mg/mL. The confocal microscopic studies revealed that SA-cys-dNF-PEG scaffolds upon containing d-NFs enhanced the proliferation rate of AD-MSCs.
The extrusion-based printing technique (10-50 um/s; Resolution >50 μm) found the optimal condition of a liquid photo-curable SA-Cys-dNFs-PEG and collagen with wall stresses of 2-16 dyne*s/cm2 (200-1600 cPs).
The optimization process and in-vivo evaluation studies of the customized cardiovascular stent made from SA-Cys-dNFs-PEG are undergoing.
Conclusion: The biomimicking hydrogels scaffolds (SA-Cys-dNFs-PEG) are robust in mechanical property and can serve as an ideal niche for AD-MSCs with immunomodulatory effects. The extrusion-based 3-D printing technique made it feasible to precisely control the hydrogel deposition in the fabrication that mimic the organ structure and cardiovascular matrix, leading to customized patient-specific bioprinting stent.
Y Lee and CH Lee: Augmented Reality for Personalized Biotechnology Advanced, 36(1): 335-43 (2018).
B Oh, RB Melchert, CH Lee: Biomimicking Robust Hydrogel for the Delivery of Mesenchymal Stem Cells, Pharm Res. 32(10):3213-27 (2015).
Chi H Lee– Kansas City, Missouri