This blog is the last in this series, for now. This is definitely an area that we will be revisiting soon.
The executive summary for this whole series, is that I think that electrochemical detection is definitely the future for aptamer based diagnosis. This is clearly an area where aptamers have a significant advantage over antibodies given their small size and their inherent flexibility.
Reasons favouring electrochemical detection with aptamers.
- With square wave detection the binding of an aptamer to a target either results in a shift in the structure of the aptamer, or it can be engineered to result in a shift in the structure. This shift can be engineered to affect the proximity of a redox agent to an electrode surface.
- With electrical impedance spectroscopy the overall charge of the surface is affected by aptamer binding. This does not require a label.
- Aptamers can be immobilized onto the electrode surface in an oriented manner.
- The smaller width of aptamers means that more aptamers can be immobilized per unit area of surface than an antibody.
- These approaches have the potential to be rapid, sensitive and inexpensive.
- Antibodies will not work well for either approach.
Constraints that need to be resolved before these technologies can be effectively commercialized.
- For EIS analysis, chip to chip variation is a significant problem. We are using machine learning to develop normalization approaches.
- For square wave analysis, the decrease in signal from one read to the next is a problem when attempting to compare signal to background.
We are also exploring graphene surfaces with partners to determine whether this provides more consistency in response.
Bottom line: Electrochemical detection has a lot of potential for diagnostics of all targets. Unfortunately there are still some difficulties that we need to overcome before this technology becomes plug and play like we need it to. At NeoVentures we welcome your thoughts and solutions to overcome these problems. We will continue this blog series on an ongoing basis reporting our results in this area, and reporting solutions that you share with us, with appropriate attribution of course.