Bioprocesses have long been ubiquitous in the production of modern pharmaceuticals and drugs. Contemporary bioprocesses are being increasingly used in the production of many other products, ranging from biodegradable plastics, packing materials, and other throwaways, to non-fossil fuels such as ethanol and biodiesel, and commonly needed human spare parts such as artificial skin and cartilage. Fluorescence-based sensing technologies, which can greatly decrease overall development time, labor, and costs, become an increasingly useful tool, particularly because their use permits a degree of miniaturization, scalability, and multiplexing that was previously unavailable.
These experiments must be done quickly to minimize development time. This requirement mandates that the experiments be done, to the extent possible, in parallel. Until recently, this initial screening was done almost exclusively in well plates or flasks, vessels that were reasonably inexpensive and thus economically feasible for a high degree of parallelism. However, these systems run mostly blind, with little or no instrumentation to track and control relevant process parameters.
Typically, the only data available to the research scientist are the results of offline measurements, which are labor intensive to take and produce results of questionable accuracy because process parameters are subject to measurable change during the sampling process. Consequently, little data are obtained regarding optimal process parameters; process optimization is generally left to be done heuristically in bioreactors. The latter systems are adequately instrumented and capable of measuring and controlling salient process parameters. However, because of the discrete and expensive nature of experiments run in such systems, a fairly limited number of experiments may be performed in an attempt to determine what constitutes optimal culture conditions. Even small errors in what are determined to be (in contrast to what actually are) optimal conditions can result in enormous increases in production costs over time. In addition, if the range of allowable variances in such conditions is not adequately explored and documented, the possibility exists that valuable and viable batches of product may be discarded because of small excursions from so-called ideal culturing conditions, even though the excursions may actually be of little consequence.
Of course, small laboratory-scale bioreactors could be used for the initial screening of cell lines and media as well as for process optimization. However, purchasing large numbers of individual bioreactors for the screening stage would be prohibitively expensive and setting up, running, breaking down, and cleaning a large number of such bioreactors would require an enormous amount of labor. If bioreactors were to be used, the degree of parallelism (and hence the number of experiments performed in a given period of time) would be quite limited or else the time required for the initial stages of the development cycle would increase dramatically.