Table 2.

Comparison of four technologies based on their advantages and disadvantages.

Detection System	Advantages	Disadvantages
Electrical (STM)	Vertical configuration: Applicable to multiple analysis with appropriate combinatorial design of detection probes Low detection limit	Time consuming Requires labeling material (conducting or semiconducting)
Electrochemical (CV)	Simple to operate Labeling material is not necessary	Sensitivity of electrochemical signal without using enzyme is very low Current flow is attenuated by biomaterials Degradation or denaturation of biomaterials might occur Not completely defined where the redox reaction occurring
Optical (LSPR)	Ease of operation High sensitivity	Not able to distinguish different binding events regarding multiple analysts
Optical (SERS)	Requires relatively lower laser intensity and longer wavelengths Rapid signal acquisition times Can be conducted under ambient conditions Broad wavenumber range Narrow band spectra	Still requires interdisciplinary research effort to develop highly sensitive and reliable system such as integration with micro fluidic assay