WO 2010/020254 discloses how to prepare a multi-layered blood product by centrifugation of blood. First, the blood is placed in a container, and the coagulation of the blood is activated during or after placing the blood in the container. During the centrifugation, the components of the blood are separated from each other and produce a three-layered blood product, which in sequential order comprises a first layer, which substantially comprises fibrin, a second, intermediate layer, which substantially comprises thrombocytes, and a third layer, which substantially comprises leukocytes. This three-layered blood product forms a coherent pad, which is separated from serum and erythrocytes. The blood product or the blood pad is suitable for the treatment of wounds. By placing the third layer closest to the wound, the wound is kept substantially aseptic as the leukocytes of the third layer counter infection and attract other cells including macrophages. The second layer substantially comprising thrombocyte contains growth-promoting factors, which stimulate the healing of the wound, whereas the third layer, which comprises substantially fibrin, offers an effective protection against contamination from the surroundings, just as the content of growth-promoting factors of the first layer is released in time. The blood product in question is suitable for autogenic use. Due to a large internal strength, density towards liquids and gasses, the blood product is also suitable for use in other surgical procedures, such as anastomosis, hernioplasties and orthopaedics.
US 2008/0023414 discloses a container unit for separating blood into a lighter and a heavier constituent by centrifugation. The container unit comprises a tubular body with an interior, a closed bottom and an open top closed by means of a closure. The inner dimension of the tubular body slightly tapers as seen from the top toward the bottom. A separating device is arranged in the interior of the tubular body at the top thereof. The separating device is circumferentially deformable and engages sealingly to the inner surface of the tubular body. When using the container unit, blood is introduced into the interior below the separating device. When the separating device is subjected to centrifugation the separating device moves downwards towards the bottom until it has moved a preselected distance. The lighter constituent flows upwards through the separating device to be situated above the separating device while the heavier constituent is situated below the separating device.
US 2010/0155319 discloses a separation assembly for separating a fluid such as blood into a heavier fraction and a lighter fraction. The separation assembly comprises a tubular body having a closed bottom end and an open upper end closed by a closure. A separator is displaceably arranged in the interior of the tubular body. The separator comprises a float and ballast, the float and the ballast being connected by bellows sealingly engaging the inner surface of the tubular body when not being subjected to centrifugal force. The overall density of the separator is between that of the heavier and lighter fraction. When using the separation assembly, blood is introduced into the interior of the tubular body below the separator, the separator being initially situated at the top end adjacent the closure. When subjected to centrifugation, the diameter of the bellows decreases and the separator moved downwards toward the bottom until it, due to its overall density, is situated between the lighter and the heavier fraction, the lighter fraction being situated above and the heavier fraction below the separator.