Over the past twenty years, functionalized pores have emerged as promising biosensors offering higher sensitivities than conventional sensors. Biodetection through pores has been used to detect and analyze different types of cells and individual (bio)molecules without labelling and using rapid and inexpensive current measurement. Historically, the first studies were conducted on biological protein nanopores. But their instability and sensitivity to experimental conditions have led to the conception more robust synthetic nanopores. The use of biomolecules to functionalize these synthetic nanopores in order to make them biomimetic remains a major challenge.

It is in this context that IRIG researchers have taken on the challenge of the local functionalization of synthetic pores by biomolecules. To do this, they imagined using an innovative technique inspired by bipolar electrochemistry (BPE). Usually, the size of the conductive object (here the pore) is one of the main physical limitations of this process: the smaller the object, the greater the potential for sufficient polarization.
Nevertheless, IRIG researchers developed a process, called contactless electro-functionalization (CLEF), which is used for promising applications in bio-detection, particularly for the analysis of living cells ^[1]. Recently [2], they adapted CLEF on planar micropores connected in parallel (Figure), this geometry making the devices more easily integrated in lab-on-chip.


Diagram of the adaptation of CLEF on through pore (A) and on planar pore (B).

They then succeeded in revealing electrochemical phenomena by electro-chemiluminescence (ECL) in these devices (collaboration with the ISM, Bordeaux). In order to generate ECL signals, the microfluidic design combined with the deoxidation of silicon (present in the inner wall of the micropores) allowed them to use voltages two orders of magnitude lower than standard BPE installations. It is the first micropore to integrate ECL characteristics for the detection of biomolecules.

The versatility of the BPE, combined with micro and nanopore technology, should allow the same concept to be applied to other types of conductive objects at the nanoscale. In addition, the approach presented opens the door to new dynamic experiments with nano-objects crossing pores where they can be addressed, modified or detected electrochemically. Finally, these micropores pave the way for the development of original analytical applications such as biomolecule capture coupled with ECL detection.