Preliminary Validation of Tumor Cell Attachment Inhibition Assay for Developmental Toxicants With Mouse S180 Cells

This study was designed to explore the possibility of using ascitic mouse sarcoma cell line (S180) to validate the mouse tumor cell attachment assay for developmental toxicants, and to test the inhibitory effects of various developmental toxicants. The results showed that 2 of 3 developmental toxicants under consideration, sodium pentobarbital and ethanol, significantly inhibited S180cells attachment to Concanavalin A-coaed surfaces. Inhibition was dependent on concentration, and the IC50 (the concentration tha reduced attachment by 50% ), of these 2 chemicals was 1.2×10-3mol/L and 1 .0 mol/L, respectively. Anoher developmental toxiant, hydmiortisone, did not show inhibitory activity. Two non-developmental toxicants, sodium chloride and glycine were also tested and these did not decrease attachment rates. The main results reported here were generally sindlar to those obtained with ascitic mouse ovdrian tumor cells as a model. Therefore, this study added further evidence to the conclusion that cell specificity does not lindt attachment inhibition to Con A-coated surfaces, so S180 cell may serve as an altemative cell model, especially when other cell lines are unavailable. Furthermore, after optimal validation, it can be suggested that an S180 cell attachment assay may be a candidate for a series of assays to detect developmental toxicants.

Cell Attachment of Periodontal Ligament Cells on Commercially Pure Titanium at the Early Stage

Summary: In order to study the character of periodontal ligament cells (PDLCs) attaching on commercially pure titanium (cpTi) by morphology and metrology on the early stage (24 h), 1×105/ml PDLCs in 2 ml culture medium were seeded on cpTi discs fixed in 24-well culture plates. Morphology of cell attachment was observed by contrast phase microscope, scanning electron microscope (SEM) and fluroscence microscopy. Cell adhesion was analyzed by MTT at 0.5, 1, 2, 4 h respectively. PDLCs could attach and spread on cpTi discs. SEM showed that PDLCs had pseudopod-like protuberance. PDLCs showed different attaching phases and reached saturation in cell number at 2 h. It was concluded that PDLCs had good biocompatibility with cpTi, and showed a regular and dynamic pattern in the process of attaching to cpTi.

Modification of Titanium Surfaces via Surface-initiated Atom Transfer Radical Polymerization to Graft PEG-RGD Polymer Brushes to Inhibit Bacterial Adhesion and Promote Osteoblast Cell Attachment

Implant-related infection is one of the key concerns in clinical medicine, so the modification of titanium to inhibit bacterial adhesion and support osteoblast cell attachment is important. In this article, two strategies were used to examine the above effects. First, modification of titanium via surface-initiated atom transfer radical polymerization（ATRP） was performed. The surface of the titanium was activated initially by a silane coupling agent. Well-defined polymer brushes of poly（ethylene glycol） methacrylate were successfully tethered on the silane-coupled titanium surface to form hydration shell to examine the anti-fouling effect. Second, functionalization of the Ti-PEG surface with RGD was performed to examine the anti-bacterial adhesion and osteoblast cell attachment ability. The chemical composition of modified titanium surfaces was characterized by X-ray photoelectron spectroscopy（XPS）. Changes in surface hydrophilicity and hydrophobicity were characterized by static water contact angle measurements. Results indicated that PEG-RGD brushes were successfully tethered on the titanium surface. And anti-bacterial adhesion ability and osteoblast cell attachment ability were confirmed by fluorescence microscopy and scanning electron microscopy. Results indicated that PEG can inhibit both bacterial adhesion and osteoblast cell attachment, while PEG-RGD brushes can not only inhibit bacterial adhesion but also promote osteoblast cell attachment.

Which form of collagen is suitable for nerve cell culture?

In this study, we investigated the effects of hydrolyzed and non-hydrolyzed collagen and two-di- mensional and three-dimensional collagen matrices on cell survival, attachment and neurite out- growth of primary cultured nerve cells using 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide （MTT） colorimetric assay and inverted microscopy. Hydrolyzed collagen facilitated nerve cell survival and neurite outgrowth, but it had no obvious influences on cell attachment. In contrast, non-hydrolyzed two-dimensional collagen matrix had no obvious effects on neurite outgrowth. These findings suggest that hydrolyzed collagen is an ideal nerve cell culture media.

Promotion of minTBP-1-PRGDN on the attachment,proliferation and collagen I synthesis of human keratocyte on titanium

AIM: To investigate the influence of minTBP-1-PRGDN on the attachment,proliferation and collagen I synthesis of human keratocyte on titanium(Ti) surface. · METHODS: The chimeric peptide RKLPDAPRGDN(minTBP-1-PRGDN) was synthesized by connecting RKLPDA(minTBP-1) to the N-terminal of PRGDN,the influence of minTBP-1-PRGDN on the attachment,proliferation and collagen I synthesis of human keratocyte on Ti surface were tested using PRGDN and minTBP-1 as controls. The keratocytes attached to the surface of Ti were either stained with FITC-labeled phalloidin and viewed with fluorescence microscope or quantified with alamar Blue method. The proliferation of keratocytes on Ti were quantified with 3-(4,5-dim-ethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide uptaking methods. The secretion of type I collagen was determined using an ELISA kit. ·RESULTS: The results showed that minTBP-1-PRGDN at a concentration of 100ng/mL was the most potent peptide to enhance the attachment of human keratocytes to the surface of Ti(1.40±0.03 folds,P =0.003),to promote the proliferation(1.26 ±0.05 folds,P =0.014) and the synthesis of type I collagen(1.530 ±0.128,P =0.008). MinTBP-1 at the same concentration could only promote the attachment(1.13±0.04 folds,P =0.020) and proliferation(1.15±0.06 folds,P =0.021),while PRGDN had no significant influence(P 】0.05). ·CONCLUSION: Our data show that the novel chimericpeptide minTBP-1-PRGDN could promote the attachment,proliferation and type I collagen synthesis of human keratocytes on the surface of titanium.

MUC5B Production Is Unaffected by Akt Inhibition in Human Lung Epithelial NCI-H292 Cells

In the human airway, the gelforming mucin subtypes MUC5B and MUC5AC play important roles in biophylaxis. However, the regulation of MUC5B production is less clear than that of MUC5AC. Therefore, the regulation of MUC5B production by cell attachment and Akt was investigated in human lung epithelial NCI-H292 cells. We found that low cell attachment to culture plates induced the upregulated production of both MUC5B and MUC5AC. Cell attachment induces the activation of Akt, a serine/threonine kinase. Cell treatment with Akt inhibitor I decreased Akt phosphorylation and activation. However, MUC5B production was unaffected by Akt inhibition, whereas MUC5AC production was upregulated. MUC5B production was also unaffected by Akt inhibition in cells cultured on type IV collagen or fibronectin. These results suggest that the production of both MUC5B and MUC5AC is regulated by cell attachment. However, the regulation of MUC5B is unaffected by Akt inhibition, in contrast to that of MUC5AC.

Eularian wall film model for predicting dynamic cell culture process to evaluate scaffold design in a perfusion bioreactor

In tissue engineering field,it is important to develop a suitable numerical model to evaluate scaffold geometry design.The experimental evaluation of the effect of each specific scaffold parameter on tissue regeneration requires large cost and long time expend.Dynamic cell culture is commonly used for generating tissues which could replace damaged tissues.A perfusion bioreactor model is developed which is able to simulate dynamic cell culture,to evaluate scaffold quality.The wall-film model is used to simulate cell attachment with the assumption that cells could be seen as liquid drops.In the process of cell attachment,the cells could impinge to a solid surface and form a liquid film which were considered as cell attached on the scaffold surface.Two types of cell-scaffold interactions were involved in numerical models including trap model and Stanton-Rutland(Cell impinge model—CIM)model.For trap model,all cells impinged the scaffold are seen as attached.For Stanton-Rutland model,four regimes of cell-scaffold interaction are involved in the cell attachment,including stick,rebound,spread,and splash,and only stick and spread are seen as attached.By comparison with two different numerical methods,the results showed that CIM model result is more related to the experimental results than trap model,which indicated that four regimes of cell-scaffold interaction occurred in cell attachment process.By evaluating two different geometry scaffold's cells seeding by these two models,the results further indicated that this model are able to use for assessing the scaffold design.