The purpose of this chapter, besides outlining the concept of Bead Injection techniques, is to provide the reader with a detailed description of  an experimental setup that will yield reliable results. It is indeed far easier to carry out microfluidic manipulations with homogenous solutions, as done by FI and SI techniques, than to move, pack, retain, monitor, unpack and discard suspensions in a reproducible way. This is why it took over 10 years to perfect the BI technique, which became truly reliable only when carried out within the “Lab-on-valve” format. Also, method  of keeping beads  in well defined suspension by pumping (3.4.24.), originally conceived by Rangel et.al  has been further perfected (Slides 3.2.6. and 3.2.7.

It is hoped that the diagrams, movie clips, and applications presented below, will convince the reader that BI techniques are now not only feasible, but also robust and reliable. BI is being promoted here with enthusiasm and confidence, since it opens yet unexplored avenues for development of novel (bio)analytical assays, for research in solid-liquid interactions, for study of quality of chromatographic supports, for optimization of immobilization of bioligands on solid supports and in biology and medical research for s tudy of live cells.



Susana S.M.P. Vidigal , Ildikó V. Tóth , António O.S.S. Rangel 


INTRODUCTION
3.1.1.
If it is worth doing, it is worth doing right.
                                                          J. MICHL