No abstract

In addition to rigidity, matrix composition, and cell shape, dimensionality is now considered an important property of the cell microenvironment which directs cell behavior. However, available tools for cell culture in two-dimensional (2D) versus three-dimensional (3D) environments are difficult to compare, and no tools exist which provide 3D shape control of single cells. We developed polydimethylsiloxane (PDMS) substrates for the culture of single cells in 3D arrays which are compatible with high-resolution microscopy. Cell adhesion was limited to within microwells by passivation of the flat upper surface through 'wet-printing' of a non-fouling polymer and backfilling of the wells with specific adhesive proteins or lipid bilayers. Endothelial cells constrained within microwells were viable, and intracellular features could be imaged with high resolution objectives. Finally, phalloidin staining of actin stress fibers showed that the cytoskeleton of cells in microwells was 3D and not limited to the cell-substrate interface. Thus, microwells can be used to produce microenvironments for large numbers of single cells with 3D shape control and can be added to a repertoire of tools which are ever more sought after for both fundamental biological studies as well as high throughput cell screening assays.

Microarrays provide a powerful analytical tool for the simultaneous analyses of thousands of parameters, be they DNA or proteins, in a single experiment. However, a number of challenges continue to hinder the widespread application of microarray assays for analytical and diagnostic purposes. Advances in detection methods can help overcome some of these challenges by improving sensitivity and reliability in signal detection and by enabling real-time detection of binding events. Thus, the aim of this review is to highlight the most promising optical microarray biosensing techniques. The principles of techniques making use of labels, including scanner type, total internal reflection type, fiber-optics-based, and SPRenhanced fluorescence, are described, along with a brief summary of labeling strategies. State of the art label-free techniques, including imaging SPR and imaging ellipsometry, are also reviewed. Examples of microarray-based assays using each technique are given to illustrate both their usefulness and their limits of detection. Furthermore, the most competitive commercial microarray systems are presented and compared with one another in the context of their detection system. Finally, a discussion of the remaining challenges as well as trends and future applications of microarrays are presented in the context of optical sensing.

EMD elicits a regenerative response in periodontal tissues that is only partly replicated by amelogenin or ameloblastin components. A synergistic effect among the various proteins and with the cells, as well as a temporal effect, may prove important aspects of the EMD response in vivo.

Dental implants made from binary titanium-zirconium (TiZr) alloys have shown promise as a high strength, yet biocompatible alternative to pure titanium, particularly for applications requiring small diameter implants. The aim of this review is to summarize existing literature reporting on the use of binary TiZr alloys for endosseous dental implant applications as tested in vitro, in animals and clinically. And furthermore to show that TiZr is “at least as good as” pure titanium in terms of biocompatibility and osseointergration. From the twelve papers that met the inclusion criteria, the current literature confirms that TiZr alloys produce small diameter implants with a strength up to 40% higher than conventional, cold-worked, grade IV titanium implants, and with a corrosion resistance and biocompatibility that is at least as good as pure titanium. The surface structure of TiZr is compatible with established surface treatments proven to aid in the osseointegration of titanium implants. Furthermore, binary TiZr alloys have been shown to achieve good osseointegration and high success rates both in animal and in clinical studies.