The objective of this research was to investigate stress-signaling patterns in response to two dimensional (2-D) and three dimensional (3-D) calcium phosphate (CP) materials using human embryonic palatal mesenchyme cells (HEPM, CRL-1486, ATCC, Manassas, VA), an osteoblast precursor cell line. Control discs and scaffolds were fabricated from hydroxyapatite (HA) and β tricalcium phosphate (TCP) ceramics. Phospho-specific antibody cell-based ELISA (PACE) technique was utilized on members of the mitogen-activated protein kinase (MAPK) cascade including; the extracellular signal-regulated kinases (ERK1/2), p38, c-Jun N-terminal kinase (JNK), and the antiapoptosis mediator protein kinase B (AKT). Quantification of these signals was evaluated during the early attachment phase of osteoblast precursor cells. In this study, it was observed that 3-D CP scaffolds significantly activated the stress mediators p38 and JNK but not ERK1/2. This signal trend was matched with an up-regulation in AKT, suggesting the ability of cells to manage high stress signals in response to 3-D CP architecture and that 3-D CP scaffolds are necessary for studies simulating a natural trabecular bone organization. The absence of these signals in 2-D CP surfaces indicated the importance of local architecture conditions on cell stress response. It was concluded from this study that osteoblast precursor cells cultured in 3-D CP scaffolds experience greater stresssignaling patterns when compared to 2-D CP surfaces.

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In this study, a polyethylene glycol-based organic additive, with quaternary ammonium cation functional groups linked to a naphthalene rings at both ends was synthesized, for through silicon via (TSV) filling. The synthesized additive strongly suppressed Cu electrodeposition under convection and successfully bifurcated the deposition surface of TSVs into active and passive regions, allowing defect-free TSV filling. However, there was a variation in TSV filling uniformity depending on the additive chain length. The chain length was adjusted using polyethylene glycol of various molecular weights as a starting material for the additive. The electrochemical investigation revealed that the chain length was related to the re-adsorption rate during Cu electrodeposition, which is critical in TSV filling. At the optimal chain length, uniform and defect-free bottom-up TSV filling was successfully achieved and TSV filling time was reduced to 500 s.