Label-free aptasensors

Figure 7.4 Label-free aptasensors based on CNT-FETs. (A) The aptamers are attached onto the sidewalls of a single-walled carbon nanotube which connects the source (S) and drain (D) electrodes. The binding of the target protein changes the electrical properties of the CNT-FETs significantly. (B) CNT-FET devices at high resolution. (See insert for color representation.)...

LABEL-FREE APTASENSORS BASED ON LOCALIZED SURFACE PLASMON RESONANCE... 

In this review we described the most commonly used label-free aptasensor strategies. Although aptamers are one of the most promising systems for applications in biosensors, their potential applications using complex matrices as real samples remain the major challenges for point-of-care applications therefore, complementary strategies involving nanomaterials are a subject of intense study. 

We are presently in the early days of the emerging technology of using aptamers and nanomaterials to modify biosensors. So far, thrombin-binding aptamer has been the topic of numerous reports, but although many improvements are required in reproducibility and sensitivity, there is no doubt that a growing number of aptamers and, it is to be hoped, nanomaterial-based label-free aptasensors will soon be used for the diagnosis and therapeutic follow-up of diseases. 

STRATEGY FOR USE OF SMART ROUTES TO PREPARE LABEL-FREE APTASENSORS FOR BIOASSAY USING DIFFERENT TECHNIQUES... 

In this chapter we discuss mainly the development of easily fabricated aptasen-sors label-free aptasensors. As novel functional nucleic acids, aptamers have displayed many advantages over traditional recognition elements, especially in simplifying the entire detection process. Thus, usually, such simple routes are fast, sensitive, and selective, and defaults must be considered. It is found that many of the easy routes are not applicable to practical detection, or rather, detection in complex biological conditions. Sensors used when no labeling is required, especially, sometimes seem to be too smartly designed to overcome disturbances in practical samples that contain various types of complexes. Therefore, more effort will be needed before these sensors can be used successfully in practical samples. 

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