Micromechanical attachment

Although the importance of Buonocore s discovery cannot be overemphasized, micromechanical attachment cannot be regarded as true adhesion. True adhesion must be on the molecular level and must involve chemical or physicochemical bonds. 

Cements based on phytic add set more quickly than their glass polyalkenoate or dental silicate cement cormterparts, but have similar mechanical properties (Table 8.2). They are unique among add-base cements in being impervious to acid attack at pH = 2-7. Unfortunately, they share with the dental silicate cement the disadvantage of not adhering to dentine. They do bond to enamel but this is by micromechanical attachment - the cement etches enamel - and not by molecular bonding. Lack of adhesive property is a grave weakness in a modern dental or bone... 

In order to be protected against environmental interference, microelectronic or microfabricated chips must be enclosed into specific packages. For some micromechanical sensors, cap wafers with etched cavities are attached hermetically onto the device wafers using anodic, eutectic, or glass frit bonding. 

Micromechanical stimulator devices have been fabricated and used to precisely assess the mechanical strain effects on the two-dimensional ceU cultures. For instance, a high-throughput perfusi(Mi-based micro-bioreactor platform was developed to exert uniform tensile strain in a controUable maimer to the attached cells within the central circular membrane (Fig. 1). This microdevice was capable of applying tensile strain similar to that experienced by the articular chondrocytes during walking in human and was used to demonstrate the effect of tensile strain on the physiology of bovine articular chondrocytes. 

---