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In this study, we prepared porous nano-hydroxyapatite/ polyamide 66 (n-HA/ PA66) porous scaffolds by injection molding method. The morphology, macrostructure and mechanical strength of the scaffolds were characterized. Osteoblasts (OBs) derived from cranial bone of SD rats were cultured and seeded on n-HA/ PA66 scaffolds. The OB/scaffold constructs were cultured for up to 18 days and the adhesion, proliferation and osteogenic activity of OBs were observed by scanning electron microscope and detected by alkaline phosphatase activity. The results showed that the porous n-HA/PA66 porous scaffolds are biocompatible and have no negative effects on the OBs in vitro. The scaffolds fulfill the basic requirements of bone tissue engineering scaffold, and have the potential application in orthopedic, reconstructive and maxillofacial surgery areas.

Using layer-by-layer (LBL) assembled method, multilayer films containing multiwall carbon nanotubes (MWNTs) and redox polymer were successfully fabricated on a screen-printed carbon electrode. X-ray photoelectron spectroscopy (XPS) and field-emission scanning electron microscopy (FE-SEM) were used to characterize the assembled multilayer films.

Laser-induced Chemical Vapor Deposition (LCVD) is an emerging technique in freeform fabrication of high aspect ratio microstructures with many practical applications. The LCVD process is kinetically limited at low temperatures and pressure. The growth rate rises exponentially with temperature and becomes mass transport limited beyond a certain threshold. While the surface temperature drives the deposition rate of a heterogeneous pyrolytic reaction, the rate obtained depends on the reaction activation energy and the ability of the precursor reactants and by-products to transport to and from the surface. To achieve precise control of the thermal deposition near the focus of a laser beam, a mathematical model for 3-D LCVD is developed taking into account both kinetically limited and mass transport limited reactions. The model describes heat transport in the substrate and deposit as well as the gas-phase mass transport and temperature in the reaction zone in order to determine growth rate. A finite difference method is developed for solving the governing equations and an iterative algorithm is presented for simulating the process. The applicability of the model is demonstrated by growing a rod from silicon deposited on a graphite substrate.

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