ABSTRACT
BACKGROUND:Studies have shown that bioactive molecules or polypeptides grafted onto the surface of polyethylene glycol (PEG) hydrogels can improve PEG bioactivities.OBJECTIVE:To manufacture PEG hydrogels capable of auto-recruiting growth factor beta1 (TGF-β1) and to study its biocompatibility. METHODS:Pure PEG hydrogels (group A), PEG hydrogels grafted on a cell adhesion peptide RGD peptides (group B), PEG hydrogels grafted with auto-recruited TGF-β1 peptide sensitive polypeptide HSNGLPL (group C), PEG hydrogels grafted with both RGD and HSNGLPL polypeptides (group D) were prepared. Contract angle of the hydrogel was detected in each group. Human bone mesenchymal stem cells were seeded onto four kinds of hydrogels. After cells attached, scanning electron microscope and LIVE/DEAD staining were done to observe cell-hydrogel compounds. Human bone marrow mesenchymal stem cells were co-cultured with ordinary culture medium (control) or four kinds of hydrogels for 1, 3, 5, 7 days, and the cell proliferation was detected by cell counting kit-8 assay. The four kinds of hydrogels were put into 24-well culture plates with addition of PBS containing TGF-β1, and 1 hour later, immunofluorescence staining was done. RESULTS AND CONCLUSION:(1) The contact angles of groups A and C were larger than those of groups B and D. (2) Under the scanning electron microscope, groups A and C had little cells attached on the hydrogel surface, but there were many cells on the hydrogel surface in groups B and D. (3) LIVE/DEAD staining showed groups A and C had little living cells, and conversely groups B and D had many living cells. (4) The results of cell counting kit-8 demonstrated that as the incubation time went on, cell proliferation activity of five different groups increased with no difference at the same time point. (5) Findings from the immunofluorescence staining showed that groups A and B had very weak fluorescence, while groups C and D had stronger green fluorescence. In conclusion, PEG hydrogels grafted with RGD and HSNGLPL polypeptides can auto-recruit TGF-β1, and have good biocompatibility.
ABSTRACT
With the development of space life science, researches on ground-based microgravity simulation become more and more important for spaceflight to complement their limited missions. It is well known that bone marrow mesenchymal stem cells (BMSCs) are pluripotent, self-renewing cells with multi-lineage differentiation capacity on the ground, but their responses under microgravity and the underlying regulatory mechanisms are poorly understood. Ground-based microgravity simulation might affect cell proliferation, apoptosis and expression of surface molecules, and induce cytoskeletal reorganization, as well as alter the differentiation potential of BMSCs. In this review, how ground based microgravity simulation mediates BMSCs’ responses and its involved mechanisms are summarized to further understand the mechano-biological coupling in such process and provide theoretical references for space flight-induced pathophysiological alterations.
ABSTRACT
Cell biology experiments in space are indispensable for investigating the effects of microgravity environment on living organisms. As an important technological means of supporting life science researche, space cell bioreactor may directly influence the data quality of space cell biology experiments and research level. To date, space cell bioreactor techniques are still under development, and lack of standard rationale. In this article, the technical progresses of space cell bioreactor were reviewed, by introducing the operational principle of several typical space cell bioreactors, analyzing the mode of culture medium supplying and character of fluid mechanics environment in space, as well as the relevant supporting techniques about the parametric controlling on temperature, dissolved oxygen and pH value and on-line microscopic imaging, so as to discuss the future perspective about space cell bioreactor techniques.
ABSTRACT
Culturing cells on planar substrate in vitro is a conventional cell biology method. However, each type of physiological tissues has its specific three-dimensional micro-structure, which provides various micro environment to regulate such biological processes as cell proliferation and differentiation. To date, a growing body of researches on the impacts of substrate micro-topography on cellular responses has been documented in the literature. It is found that micro-topograhical substrate can manipulate cell spreading, migrating, orientating, cytoskeleton remodeling, and stem cell differentiation, which are crucial to ex vivo tissue construction and surface modification of medical implanting materials. This review discusses the recent progresses of the effects of substrate micro-topography on cellular responses and the underlying mechanisms of mechano-biological coupling.
ABSTRACT
Objective To investigate the specific roles of gap junction and ATP in mechanical stimulation induced calcium transfer in osteoblasts. Methods The isolated osteoblastic pattern without gap junctions was established by using the micropatterning method. Then fluid shear stress was applied on cells using the flow chamber to observe and analyze the characteristic parameters of calcium response. Results Multiple calcium response still occurred in osteoblastic pattern without gap junction, but the response time to the first responsive peak was much longer than that with gap junction. When the intracellular and extracellular calcium ions were removed, only 40% cells responded to the mechanical stimulation, with single peak and multiple peaks accounting for 50%, respectively. If ATP pathway was blocked, only 20% cells responded, most of which showed single peak. Conclusions ATP was the major pathway mediating intercellular calcium transfer, while the gap junction was not the necessary one.