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The growing interest in scaffold-guided tissue engineering (TE) to guide and support cell proliferation in the repair and replacement of craniofacial and joint defects gave rise to the quest for a precise technique to create such scaffolds. Conventional manual-based fabrication techniques have several limitations such as the lack of reproducibility and precision. Rapid prototyping (RP) has been identified as a promising technique capable of building complex objects with pre-defined macro- and microstructures. The research focussed on the viability of using the selective laser sintering (SLS) RP technique for creating TE scaffolds. A biocomposite blend comprising of polyvinyl alcohol (PVA) and hydroxyapatite (HA) was used in SLS to study the feasibility of the blend to develop scaffolds. The biocomposite blends obtained via spray-drying technique and physical blending were subjected to laser-sintering to produce test specimens. The SLS-fabricated test specimens were characterized using scanning electron microscopy and X-ray diffraction. The test specimens were also tested for bioactivity by immersing the samples in simulated body fluid environment. The results obtained ascertained that SLS-fabricated scaffolds have good potential for TE applications.

In this paper, SU-8 EPON-based photoresist (PR) polymerization optimization and its possible microfluidic and MEMS applications are reported. First, the optimization results of SU-8 under UV lithography are reported. The parameters which could have an influence on the lithography quality were chosen and optimized by a three-level, L9 orthogonal array of the Taguchi method. By optimization, the optimal parameter range and the weighted per cent of a parameter on the final results were determined. For SU-8-5 and SU-8-50, many microstructures with thicknesses of more than 100 and 500 µm and aspect ratios of more than 20 and 50 were obtained with high resolution. The optimization results show that the prebake time plays the key role in the quality, which is different from the previously published results. With the optimization results obtained, some possible applications of SU-8 were developed and demonstrated. These applications included using SU-8 as a structural material for a microfluidic system, as a micromold for electroplating, as a master for plastic hot-embossing, and even as a mask for some wet-etching processes.

The ability to have precise control over porosity, scaffold shape, and internal pore architecture is critical in tissue engineering. For anchorage-dependent cells, the presence of three-dimensional scaffolds with interconnected pore networks is crucial to aid in the proliferation and reorganization of cells. This research explored the potential of rapid prototyping techniques such as selective laser sintering to fabricate solvent-free porous composite polymeric scaffolds comprising of different blends of poly(ether-ether-ketone) (PEEK) and hydroxyapatite (HA). The architecture of the scaffolds was created with a scaffold library of cellular units and a corresponding algorithm to generate the structure. Test specimens were produced and characterized by varying the weight percentage, starting with 10 wt% HA to 40 wt% HA, of physically mixed PEEK-HA powder blends. Characterization analyses including porosity, microstructure, composition of the scaffolds, bioactivity, and in vitro cell viability of the scaffolds were conducted. The results obtained showed a promising approach in fabricating scaffolds which can produce controlled microarchitecture and higher consistency.

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