Slide- and Micoarray-Based Biosensors Using Noble Metal Nanoparticles - From Bioimaging to Biosensors: Noble Metal Nanoparticles in Biodetection - page 58

4.1 Introduction
The development of biosensors for the analysis of biomolecular
recognition and biomolecular interactions, such as diagnosis
and monitoring of diseases, drug discovery, proteomics, and
environmental detection of biological agents, is in progress to ind
methods that enable simple but eficient and sensitive afinity-
based detection schemes. Some methods required labeling of the
target analyte with luorescent dyes or radioactive markers often
interfere with the biorecognition reactions under investigation (see
Fig. 4.1A). Moreover, the labeling process is a time-consuming step
during the analysis process and it is dificult to homogeneously
label multiple targets in a complex biological sample. Enzyme-
linked immunosorbent assay (ELISA) is an attractive and well-
established approach to avoid this problem by using some kind of
labeled secondary recognition element which binds speciically
to already captured target molecules in a subsequent step of the
analysis (see Fig. 4.1B). 1 However, this assay does not allow for real-
time analysis of the biomolecular interactions and cannot obtain
essential information for the determination of reaction rate, afinity
constants, and kinetic pathways.
Figure 4.1 Illustration of two different schemes for biosensing: (A) target
analytes are labeled with luorescent dyes or radioactive
markers; (B) secondary recognition elements with enzyme-
labeled are used for detection of target analyte.
Fundamentally, a biosensor is derived from the coupling of a
ligand-receptor binding reaction to a signal transducer. A large
number of transducer principles are currently being utilized in