The Zetos System is a novel 3D Bioreactor (Zetos?) capable of maintaining human bone biopsies in a viable and responsive state for up to 45 days.
Figure 1. Ex vivo bone loading culture system. Microprocessor controlled low pulsation dispensing pump (A) allows diffusion of fresh media (B) through the bone cores within the chambers (C). The bone cores are stimulated daily within the ‘Zetos’ computer controlled mechanical loading device (D). The device is 30 cm high, made of stainless steel surrounding a piezoelectric stack linked to a voltage amplifier to enable expansion and contraction to apply and remove force onto the chamber piston and bone core. There is a preload knob on the top to place a force onto each piston. It has an opening for insertion of the individual chambers (front, bottom) daily loading of the bone cores. Three metal rods inside this opening ensure that the chambers are always inserted correctly.
Figure 2. a) Stainless steel platen base (B). On top of the chamber, when in use, there is a stainless steel platen cylinder (C) sealed by an X-ring (double headed arrow) which also provides some flexibility to minimize tilting of the piston around the vertical axis. The polycarbonate chamber has an entry and exit port to allow media to enter and leave the chamber (fig 2b). An O-ring (O) at the bottom of the chamber seals it to the base plate (B). The bone core is cushioned by two gaskets at the centre (arrow) that were designed to force the media through the bone (and not flow around the periphery). b) Constructed chamber, depicting the location of base plate (B), cylinder (C) and media exit and entry points. c) Cross section through the assembled chamber complete with bone core.