Biomedical applications cavity size

Among the various useful polymer materials, recent years have witnessed a strong rise in the use of polycarbonates as a material of choice in biomedical applications. Lee et al. examined the behavior of MG63 osteoblast-like cells cultured on a polycarbonate (PC) membrane surface with different micropore sizes (200 nm-8.0 pm) [29]. Welle et al. described electrospun aliphatic polycarbonate as tailored tissue scaffold, where the photochemical bulk modification indicates the possibility of spatial control of the biodegradation rate [30]. In an earlier section we mentioned the use of track-etched polycarbonate membranes that have been introduced as substrate for perfused cell culture in 3D format [31]. The microscopic cavities of the polymer scaffold provide three-dimensionality and nanoscopic pores provide nourishment to the cell culture from all around. Therefore, it is interesting to develop polycarbonate chemistry so that the desired functional groups and molecules can be introduced to the surface for obtaining cell substrate response. 

Pillararenes (PA), a new kind of paracyclophane, were first synthesized in 2008 as pillar[5]arene (PA[5]) and were recognized as a new generation of supramolecular host because of their unique pillar structural feature, nanometer-sized (<1.0nm) cavity, and multiple fiinctionalizable sites. In the last few years, these new types of compound have shown biomedical applications in the construction of artificial channels for transmembrane transport of physiologically active solutes and vesicles for drug delivery, which will be reviewed in this chapter. 

G. Tovar describes one of the novel chemical applications of modern colloidal systems by using such miniemulsions (in addition to classical suspension polymerization) for molecular imprinting. Here, the stable nanoreactor situation is used to synthesize particle surfaces with molecular sized cavities for biomedically relevant species or species to be separated from each other. Such receptor sites are nowadays preferentially made by the pathways of modern colloid chemistry. 

---