The need for versatile and economic industrial scale technologies for culturing anchorage-dependent mammalian cells is becoming more evident. This is a result of the increasing demand for vaccines and the use of mammalian cells for some of the new, emerging biopharmaceuticals. Microcarrier beads in bioreactor systems are being applied as a large scale production method. SoloHill is developing a family of unique microcarrier products which are superior to those currently available. The overall aim of this research is to develop a novel small microcarrier bead (38-63 micromoles) which will foster the aggregation of cells. This will encourage the use of microcarriers for conditions where higher cell densities have been shown to be advantageous. Specifically we will (l) demonstrate that higher cell densities can be achieved under conditions where extensive clumping occurs. We will characterize the bead-to-bead clumps on small (less than 63 micromoles) and large (150-212 micromoles) beads. And, we will (2) demonstrate that cells maintained under conditions of high cell density on clumped beads are metabolically active and produce higher levels of useful products including infectious virus than cells grown under conventional conditions (in which clumping is minimized).