Biomaterials with suitable surface modification strategies are contributing significantly to the rapid development of the field of bone tissue engineering. Despite these encouraging results, utilization of biomaterials is poorly translated to human clinical trials potentially due to lack of knowledge about the interaction between biomaterials and the body defense mechanism, the “immune system”. The highly complex immune system involves the coordinated action of many immune cells that can produce various inflammatory and anti‐inflammatory cytokines. Besides, bone fracture healing initiates with acute inflammation and may later transform to a regenerative or degenerative phase mainly due to the cross‐talk between immune cells and other cells in the bone regeneration process. Among various immune cells, macrophages possess a significant role in the immune defense, where their polarization state plays a key role in the wound healing process. Growing evidence shows that the macrophage polarization state is highly sensitive to the biomaterial's physiochemical properties, and advances in biomaterial research now allow well controlled surface properties. This review provides an overview of biomaterial‐mediated modulation of the immune response for regulating key bone regeneration events, such as osteogenesis, osteoclastogenesis, and inflammation, and it discusses how these strategies can be utilized for future bone tissue engineering applications.

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Nanomaterials are used in diverse fields including food, cosmetic, and medical industries. Titanium dioxide nanoparticles (TiO2-NP) are widely used, but their effects on biological systems and mechanism of toxicity have not been elucidated fully. Here, we report the toxicological mechanism of TiO2-NP in cell organelles. Human bronchial epithelial cells (16HBE14o-) were exposed to 50 and 100 μg/mL TiO2-NP for 24 and 48 h. Our results showed that TiO2-NP induced endoplasmic reticulum (ER) stress in the cells and disrupted the mitochondria-associated endoplasmic reticulum membranes (MAMs) and calcium ion balance, thereby increasing autophagy. In contrast, an inhibitor of ER stress, tauroursodeoxycholic acid (TUDCA), mitigated the cellular toxic response, suggesting that TiO2-NP promoted toxicity via ER stress. This novel mechanism of TiO2-NP toxicity in human bronchial epithelial cells suggests that further exhaustive research on the harmful effects of these nanoparticles in relevant organisms is needed for their safe application.

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A porous anodic aluminum oxide ͑AAO͒ template was fabricated selectively on a patterned substrate from a sputter-deposited Al film. The pattern size was varied from 2 to 500 m with a depth of 1.5 m. The overall surface undulation of Al resulting from the underlying patterns was planarized by chemical mechanical polishing. During the anodization of the confined Al, the anodization rate was significantly retarded at the vertical sidewall of the pattern. This suggests that the stress should be carefully controlled for the successful integration of a porous AAO structure on a patterned substrate.Anodic aluminum oxide ͑AAO͒ is known for its self-assembled periodic pore structure with a pore size of tens of nanometers and is widely used as a template for the formation of various nanostructures and nanodevices. 1-4 Most notably, the development of a twostep anodization process to form a more or less aligned pore structure 5 and the formation of aligned pore nucleation sites using prepatterned nanoimprint indentation 6-8 greatly facilitates the application of this template. However, the use of this material as a template for nanodevices is relatively new, and several critical issues need to be resolved before the template can be applied successfully.The formation of a AAO pore array on selective areas of a wafer is an important step when we are applying a porous AAO as a template incorporated in the process for fabricating integrated circuits ͑IC͒. Indeed, several methods for defining an AAO template on selective areas of a wafer have been reported. 9-11 One method uses the selective opening of a surface dielectric layer, which is deposited on the top of an Al film by patterning, which defines the AAO area. 9 However, this approach has an inherent limitation because the pore propagates underneath the dielectric passivation layer. 9 Another method typically employs the formation of AAO over the whole area of a wafer first followed by the selective etching of the unnecessary area using wet chemicals. 10,11 In this case, it is difficult to define the small feature size of a patterned AAO area because the etching of AAO is commonly carried out by wet-chemical processes. Moreover, further steps are needed to passivate each patterned AAO area after the etching process. ExperimentalThis paper proposes a new approach to forming AAO on selective areas of a wafer, which are defined as contacts and trenches. Figure 1 shows a schematic diagram showing the processing steps. First, a TEOS SiO 2 ͑2 m͒ layer was deposited on a Si wafer by plasma-enhanced chemical vapor deposition ͑PECVD͒ ͑P-5000, Applied Materials͒. Using the standard optical lithography process, patterns with various widths ͑2-500 m͒ were transferred to the SiO 2 layer by reactive ion etching ͑RIE͒ ͑P-5000, Applied Materials͒ to produce a pattern depth of 1.5 m. Ti ͑50 nm͒, TiN ͑50 nm͒, and Al ͑8 m͒ were successively deposited by a direct current ͑dc͒ magnetron sputtering on the patterned SiO 2 . Second, the topology of the Al film due to the underlying patterns was re...

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A new class of nanoporous organosilicate thin films with balanced mechanical and low dielectric properties has been designed and prepared using covalently bonded adamantylphenols as pore-generating (porogen) materials. The adamantylphenol groups were grafted or bridged to poly(methyl silsesquioxane) (PMSSQ) polymers through propyl linkers and the thermal decomposition of such porogens through the cleavage of covalent bonds during curing was confirmed by FT-IR, TGA, and GC-MS. One of the nanoporous thin films examined in this study contains nanopores, less than 10 nm, within the films with 18% porosity, as characterized by X-ray reflectivity, ellipsometry, and nitrogen sorption analysis. Elastic modulus of a nanoporous film measured by a nanoindenter was significantly increased to 5.5 GPa, while maintaining the dielectric constant of 2.3, which is due to the partial formation of silica structure by the decomposition of residual propenyl groups after the bond cleavage of porogens and also due to the enhanced cross-linking density in the case of bridge-PMSSQ.