If you know me quite well, you’d know that I have a particular interest in the field of bio-imaging and sensing systems. I enjoy reading about the development and refinement of biosensor systems every now and then, because this field never ceases to surprise me.
Recently, I have stumbled upon an interesting paper. As the title suggests, this paper described a new electrochemical sensing approach using gold nanoparticles (AuNP) and quantum dots (QD) to detect the epithelial-mesenchymal transition (EMT) using E-cadherin (a cell-cell adhesion protein) as the biomarker, which is a novel application.
The process of EMT, simply put, is when epithelial cells lose their polarity and adhesion, which grants them migratory and invasive properties to become mesenchymal cells. The detection of such process can be crucial in the diagnosis of cancer progression and metastasis, although other processes like tissue regeneration and embryogenesis has its applications too (Kalluri, Weinberg, 2009).
This paper anchors on the foundation of which E-cadherin is downregulated during EMT initiation. Therefore, when EMT initiates, the reading of the system should drop as compared to normal cells. The ‘reading’ here is done through utilization of E-cadherin antibody-QD (E-cad-Ab-QD) and carbon nanotube-gold nanoparticle (CNT-AuNP) as the detection platform (Du et al., 2020). The modified antibody will bind to E-cadherin, and the interaction between the QD on the antibody and the electrode detection platform will generate a current.
The logic here is simple: With a reduced E-cadherin on the surface of an EMT cell, the current generated from the QD-electrode interaction will decrease. When comparing to the normal cell reading, there would be a clear difference in the current generated. Hence, the process of EMT could be deduced from that. This is demonstrated from the figure shown below, of which I took from the paper.
Electrochemical sensing using nanoparticles and quantum dots have been intensively reported lately, and this paper is just one of the novel applications of this system. In my opinion, there are great potentials in this field of research, and in the current stage there are still refinements to be made. If quantum dots can be conjugated to any antibody, perhaps there is a possibility for detection of any type of proteins following the same methodology mentioned in this paper. It will be interesting if this process can be standardized and maybe one day we can achieve a faster and more accurate electrochemical detection system.
(Du et al., 2020)
Du, X., Zhang, Z., Zheng, X., Zhang, H., Dong, D., Zhang, Z., Liu, M. & Zhou, J. 2020, An electrochemical biosensor for the detection of epithelial-mesenchymal transition, Springer Science and Business Media LLC.
Kalluri, R. & Weinberg, R.A. 2009, “The basics of epithelial-mesenchymal transition”, The Journal of clinical investigation, vol. 119, no. 6, pp. 1420-1428.