Silk fibroins modify the atmospheric low temperature plasma-treated poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) film for the application of cardiovascular tissue engineering

Tissue engineered scaffold is one of the hopeful therapies for the patients with organ or tissue damages. The key element for a tissue engineered scaffold material is high biocompatibility. Herein the poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) film was irradiated by the low temperature atmospheric plasma and then coated by the silk fibroins (SF). After plasma treatment, the surface of PHBHHx film became rougher and more hydrophilic than that of original film. The experiment of PHBHHx flushed by phosphate buffer solution (PBS) proves that the coated SF shows stronger immobilization on the plasma-treated film than that on the untreated film. The cell viability assay demonstrates that SF-coated PHBHHx films treated by the plasma significantly supports the proliferation and growth of the human smooth muscle cells (HSMCs). Furthermore, the scanning electron microscopy and hemotoylin and eosin (HE) staining show that HSMCs formed a cell sub-monolayer and secreted a large amount of extracellular matrix (ECM) on the films after one week's culture. The silk fibroins modify the plasma-treated PHBHHx film, providing a material potentially applicable in the cardiovascular tissue engi-neering.

Laser patterning for the study of MSC cardiogenic differentiation at the single-cell level

Mesenchymal stem cells(MSCs)have been cited as contributors to heart repair through cardiogenic differentiation and multiple cellular interactions,including the paracrine effect,cell fusion,and mechanical and electrical couplings.Due to heart–muscle complexity,progress in the development of knowledge concerning the role of MSCs in cardiac repair is heavily based on MSC–cardiomyocyte coculture.In conventional coculture systems,however,the in vivo cardiac muscle structure,in which rod-shaped cells are connected end-to-end,is not sustained;instead,irregularly shaped cells spread randomly,resulting in randomly distributed cell junctions.Consequently,contact-mediated cell–cell interactions(e.g.,the electrical triggering signal and the mechanical contraction wave that propagate through MSC–cardiomyocyte junctions)occur randomly.Thus,the data generated on the beneficial effects of MSCs may be irrelevant to in vivo biological processes.In this study,we explored whether cardiomyocyte alignment,the most important phenotype,is relevant to stem cell cardiogenic differentiation.Here,we report(i)the construction of a laser-patterned,biochip-based,stem cell–cardiomyocyte coculture model with controlled cell alignment;and(ii)single-cell-level data on stem cell cardiogenic differentiation under in vivo-like cardiomyocyte alignment conditions.

Differential Responses of Transplanted Stem Cells to Diseased Environment Unveiled by a Molecular NIR-II Cell Tracker

Stem cell therapy holds high promises in regenerative medicine.The major challenge of clinical translation is to precisely and quantitatively evaluate the in vivo cell distribution,migration,and engraftment,which cannot be easily achieved by current techniques.To address this issue,for the first time,we have developed a molecular cell tracker with a strong fluorescence signal in the second near-infrared(NIR-II)window(1,000-1,700 nm)for real-time monitoring of in vivo cell behaviors in both healthy and diseased animal models.The NIR-II tracker(CelTrac1000)has shown complete cell labeling with low cytotoxicity and profound long-term tracking ability for 30 days in high spatiotemporal resolution for semiquantification of the biodistribution of transplanted stem cells.Taking advantage of the unique merits of CelTrac1000,the responses of transplanted stem cells to different diseased environments have been discriminated and unveiled.Furthermore,we also demonstrate CelTrac1000 as a universal and effective technique for ultrafast real-time tracking of the cellular migration and distribution in a 100μm single-cell cluster spatial resolution,along with the lung contraction and heart beating.As such,this NIR-II tracker will shift the optical cell tracking into a single-cell cluster and millisecond temporal resolution for better evaluating and understanding stem cell therapy,affording optimal doses and efficacy.