Mechanisms of Cup-Shaped Vesicle Formation Using Amphiphilic Diblock Copolymer

A cup shape is a dynamic morphology of cells and organelles. With the aim of elucidating the formation of the biotic cup-shaped morphology, this study investigated cup-shaped vesicles consisting of an amphiphilic diblock copolymer from the aspect of synthetic polymer chemistry. Cup-shaped vesicles were obtained by the polymerization-induced self-assembly of poly(methacrylic acid)-block-poly(n-butyl methacrylate-random-methacrylic acid), PMAA-b-P(BMA-r-MAA), in an aqueous methanol solution using the photo nitroxide-mediated controlled/living radical polymerization technique. Field emission scanning electron microscopic observations demonstrated that the cup-shaped vesicles were suddenly formed during the late stage of the polymerization due to the extension of the hydrophobic P(BMA-r-MAA) block chain. During the early stage, the polymerization produced spherical vesicles rather than a cup shape. As the hydrophobic block chain was extended by the polymerization progress, the spherical vesicles reduced the size and were accompanied by the generation of small particles that were attached to the vesicles. The vesicles continued to reduce the size due to further extension of the hydrophobic chain;however, they suddenly grew into cup-shaped vesicles. This growth was accounted for by a change in the critical packing shape of the copolymer due to the hydrophobic chain extension. These findings are helpful for a better understanding of the biotic cup-shaped vesicle formation.

Reactive perforating collagenosis

Histological features of reactive perforating collagenosis (RPC) vary according to stage of disease.The pathological manifestations of lesions that did not form an umbilical fossa in the early stages,degenerate collagen fibers accumulate in dermal papillae and epidermal hyperplasia may be seen.The upper epidermis is atrophied,and a thin layer of keratinized material is visible in the center.Typical acanthosis is visible on both sides of the lesion.In the late stage,epidermis cup-shaped depression can be seen in the epidermis,and it filled with columnar overlying keratin plug that consists of parakeratotic debris,denatured collagen fibers and inflammatory cells[1].The epidermis below is obviously thin.It is locally visible that degenerative collagen fibers pass through the epidermi vertically.The epidermis on both sides of the cup-shaped structure show acanthosis and hyperkeratosis,and infiltration of lymphoid cells is observed in the superficial dermis and around the blood vessels (Figure 1).Blue-stained collagen fibers are visible in the superficial dermis and epidermis in Masson staining.