Stereolithography is a solid freeform technique (SFF) that was introduced in the late 1980s. Although many other techniques have been developed since then, stereolithography remains one of the most powerful and versatile of all SFF techniques. It has the highest fabrication accuracy and an increasing number of materials that can be processed is becoming available. In this paper we discuss the characteristic features of the stereolithography technique and compare it to other SFF techniques. The biomedical applications of stereolithography are reviewed, as well as the biodegradable resin materials that have been developed for use with stereolithography. Finally, an overview of the application of stereolithography in preparing porous structures for tissue engineering is given.

Differential scanning calorimetry (DSC) was performed on aqueous solutions of polyCZVisopropylacrylamide-co-butyl methacrylate-co-X), with X being hydrophilic, hydrophobic, cationic, or anionic comonomers, to elucidate the mechanism of temperature-induced phase separation and the effect of comonomer content, hydrophilicity, and charge on the lower critical solution temperature (LCST). The endothermic heat of phase separation, which is related to the breaking of hydrogen bonds between water molecules surrounding hydrophobic moieties on the polymer, was a linear, decreasing function of the LCST. This suggests that the hydrophobic interactions between polymer side groups, which are the major driving force for phase separation, are enhanced at elevated temperatures due to a decrease in the structuring of water around hydrophobic side groups. It is concluded that the changes in LCST caused by the incorporation of comonomers are due to changes in overall hydrophilicity of the polymer and are not due to a direct influence of comonomer hydrophilicity or charge on the structuring of water around hydrophobic groups.

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In the past decade, polymersomes (also referred to as polymeric vesicles) have attracted rapidly growing interest based on their intriguing aggregation phenomena, cell and virus-mimicking dimensions and functions, as well as tremendous potential applications in medicine, pharmacy, and biotechnology. Unlike liposomes self-assembled from low molecular weight lipids, polymersomes are in general prepared from macromolecular amphiphiles of various architectures including amphiphilic diblock, triblock, graft and dendritic copolymers. Polymersomes exhibit very unique features highlighted with high stability, tunable membrane properties, versatility, and capacity of transporting hydrophilic as well as hydrophobic species such as anticancer drugs, genes, proteins, and diagnostic probes. Recently, much effort has been directed to the development of intelligent polymersomes that respond to internal or external stimuli, in particular, pH, temperature, redox potential, light, magnetic field, and ultrasound, either reversibly or nonreversibly. Stimuli-sensitive polymersomes have emerged as novel programmable delivery systems in which the release of the encapsulated contents can be readily modulated by the stimulus. The stimuli-responsive release may result in significantly enhanced therapeutic efficacy and minimized possible side effects. It is also feasible to form and disassemble polymersomes in water simply by applying an appropriate stimulus. In this article, recent advances in stimuli-sensitive polymersomes have been reviewed, and perspectives on future developments have been discussed.