The invention provides a system for preparing an autologous solid-fibrin web suitable for regenerating tissue in a living organism. The system includes a sealed primary container containing a separation medium and a low-density high-viscosity liquid. The separation medium separates red blood cells from plasma when the container contains blood and is centrifuged, and the primary container has a first pressure. The system further includes a sealed secondary container containing a calcium-coagulation activator. The secondary container has a second pressure that is less than the first pressure. The system also comprises a transfer device including a cannula having a first end and a second end. The first and second ends puncture the sealed primary and secondary containers in order to provide fluid communication between the first and second containers. The low-density high-viscosity liquid of the primary container blocks flow through the cannula upon entering therein.