Emulsions as Biosensors

A biosensor is used to determine various parameters associated with biological species such as single biomolecules, molecular complexes, viruses, cells, and tissues. Understanding mechanisms, from the molecular to the cellular level, is 

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Abstract This chapter summarizes the properties and most representative applications of pH-responsive polymers in the biomedical field.The most common methodologies to synthesize pH-responsive polymers such as emulsion polymerization, group transfer polymerization, atom transfer radical polymerization and reversible addition-fragmentation chain transfer polymerization are described. This chapter also discusses the most important applications of pH-responsive polymers in drug and gene delivery and the use of these systems as biosensors, taking into account the chemical and physical properties of these smart polymer systems. 

These two examples show how emulsion-based magnetic colloids can become the essential elements for two apparently very different issues. In fact, this section introduces the basics of using superparamagnetic emulsion-based colloids, and their spontaneous self-assembling ability under a field, as new biosensors. The... 

In other applications, proteins are adsorbed by purpose, for example, as immobilized enzymes in biosensors and bioreactors, immunoglobulins in immunoassays, drugs in drug targeting and controlled release systems, and as stabilizers of dispersions, emulsions, and foams in foodstuffs, pharmaceuticals, and cosmetics. 

Besides the functionalization of the biosensor surface, when micro- or nanoparticles are used (eg, magnetic particles), they also need to be functionalized. For instance, functional beads prepared by emulsion polymerization or dispersion polymerization offer a large specific surface for chemical binding. These small particles can be advantageously used as a mobile substrate for bioassays, or even for in vivo applications, as they can be easily recovered from dispersion (Gijs, 2004). 

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