Scaffold effects on osteogenic differentiation of equine mesenchymal stem cells: an in vitro comparative study.

The in vitro viability, osteogenic differentiation, and mineralization of four different equine mesenchymal stem cells (MSCs) from bone marrow, periosteum, muscle, and adipose tissue are compared, when they are cultured with different collagen-based scaffolds or with fibrin glue. The results indicate that bone marrow cells are the best source of MSCs for osteogenic differentiation, and that an electrochemically aggregated collagen gives the highest cell viability and best osteogenic differentiation among the four kinds of scaffolds studied.

Platelet Rich Fibrin in the revitalization of tooth with necrotic pulp and open apex.

Regeneration of pulp-dentin complex in an infected necrotic tooth with an open apex is possible if the canal is effectively disinfected. The purpose of this case report is to add a regenerative endodontic case to the existing literature about using Platelet Rich Fibrin (PRF). A nine year old boy who accidently broke his immature maxillary central incisor tooth, developed pulpal necrosis with apical periodontitis. After the access cavity preparation, the canal was effectively irrigated with 20 ml of 5.25% sodium hypochlorite solution and 10ml of 0.2% chlorhexidine solution and dried with paper points. Triple antibiotic paste was placed inside the canal and left for 21 days. 12 ml of whole blood was drawn from the patient's right antecubital vein and centrifuged for 10 minutes to obtain the Choukroun's PRF. After the removal of the triple antibiotic paste, the PRF was placed into the canal till the level of cementoenamel junction and 3mm of grey MTA was placed directly over the PRF clot. The setting of MTA was confirmed 3 days later and the tooth was double sealed with GIC and Composite restoration. After 1 year the clinical examination revealed negative responses to percussion and palpation tests. The tooth responded positively to cold and electric pulp tests. Radiographic examination revealed continued thickening of the dentinal walls, root lengthening, regression of the periapical lesion and apical closure. On the basis of the results obtained in our case report we conclude that revitalization of necrotic infected immature tooth is possible under conditions of total canal disinfection and PRF is an ideal biomaterial for pulp-dentin complex regeneration.

Controlling volatility in solid-state, redox-based memory devices using heterojunction barriers to ion transport.

In this work, we show the ability to tune the volatility of redox-based memory by designing barriers to ion drift. By changing the nature and properties of the barrier material, the key performance metric (ratio of retention time to read/write time) could be altered to yield ratios in the range of 1 to 10(9).

Controlled cell proliferation on an electrochemically engineered collagen scaffold.

Therapies for corneal disease and injury often rely on artificial implants, but integrating cells into synthetic corneal materials remains a significant challenge. The electrochemically formed collagen-based matrix presented here is non-toxic to cells and controls the proliferation in the corneal fibroblasts seeded onto it. Histology and biomolecular studies show a behavior similar to corneal stromal cells in a native corneal environment. Not only is this result an important first step toward developing a more realistic, multi-component artificial cornea, but it also opens possibilities for using this matrix to control and contain the growth of cells in engineered tissues.

Correlating mechanical properties with aggregation processes in electrochemically fabricated collagen membranes.

We show that mechanical stiffness is a useful metric for characterizing complex collagen assemblies, providing insight about aggregation products and pathways in collagen-based materials. This study focuses on mechanically robust collagenous membranes produced by an electrochemical synthesis process. Changing the duration of the applied electric field, or adjusting the electrolyte composition (by adding Ca(2+), K(+), or Na(+) or by changing pH), produces membranes with a range of Young's moduli as determined from force-displacement measurements with an atomic force microscope. The structural organization, characterized by UV-visible spectroscopy, Raman spectroscopy, optical microscopy, and atomic force microscopy, correlates with the mechanical stiffness. These data provide insights into the relative importance of different aggregation pathways enabled by our multiparameter electrochemically induced collagen assembly process.