APTAMERS-FUNCTIONALIZED NANOPORE FOR HIGLY-SENSITIVE SPECIFIC PROTEIN DETECTION
Yong Chin Seow, Slaven Garaj
Graphene Research Centre, National University of Singapore, Singapore
Early detection and treatment of diseases has be revolutionised by the research efforts in proteomics and genomic research, and the development of the underlying biosensing technologies. Nanopore sensors are prominent example of such technology, capable of analysing individual biomolecules with high accuracy, even capable of reading long DNA sequences. Here we demonstrate a new nanoporebased sensors, capable of specific protein detection with unmatched sensitivity; reusable, inexpensive and easy to implement.
A nanopore sensor consists of nanometre-scale pore in a membrane separating two chambers filed with electrolyte. The ionic current through trough the nanopore is highly sensitive on the nanopore’s geometry, and has been previously used to detect and analyse translocating biomolecules. Our device consists of a nanopore functionalised with specific aptamer receptors, and we could precisely detect the binding of proteins as a change in nanopore’s electrical conductivity due the change in its geometry. By applying voltage across the membrane, we electrophoretically concentrated the proteins, and were able to sample comparatively large volume of the analyte solution. This leads to the ultra-high sensitivity, in range from nanomolar to femtomolar, rivalling the capability of the FET protein sensor without their complex fabrication process. The localized electric field at the mouth of the nanopore facilitated the formation of stable bond between the functionalized layer and protein molecules leading to the accumulative binding of protein molecules at the surrounding pore region. The cycling of electric fields enables fast reversible molecules detachment, and the fast regeneration of the sensor. We present a systematic study on various factors affecting the behaviour and the detection speed of the sensor. The aptamer-functionalized nanopore sensor holds enormous potential in commercialization of low cost and high performance protein sensors catering the global need for early diseases dignostic and personalized medical theatments.