C. Ignazio Santo, G. Conejo-Cuevas, F. Paolucci, F. J. Del Campo, G. Valenti

Electrochemiluminescence (ECL) is nowadays a powerful technique widely used in biosensing and imaging, offering high sensitivity and specificity for detecting and mapping biomolecules. Screen-printed electrodes (SPEs) offer a versatile and cost-effective platform for ECL applications due to their ease of fabrication, disposability, and suitability for large-scale production. This research introduces a novel method for improving the ECL characteristics of screen-printed carbon electrodes (SPCEs) through the application of CO₂ laser treatment following fabrication. Using advanced ECL microscopy, we analyze three distinct carbon paste-based electrodes and show that low-energy laser exposure (ranging from 7 to 12 mJ·cm^–2) enhances the electrochemical performance of the electrodes. This enhancement results from the selective removal of surface binders and contaminants achieved by the laser treatment. We employed ECL microscopy to characterize the ECL emission using a bead-based system incorporating magnetic microbeads, like those used in commercial platforms. This approach enabled high-resolution spatial mapping of the electrode surface, offering valuable insights into its electrochemical performance. Through quantitative assessment using a photomultiplier tube (PMT), it was observed that GST electrodes could detect biomarkers with high sensitivity, achieving an approximate detection limit (LOD) of 11 antibodies per μm². These findings emphasize the potential of laser-modified GST electrodes in enabling highly sensitive electrochemiluminescent immunoassays and various biosensing applications.

A. Fiorani, C. Ignazio Santo, K. Sakanoue, D. Calabria, M. Mirasoli, F. Paolucci, G. Valenti, Y. Einaga

We developed a sensing strategy that mimics the bead-based electrogenerated chemiluminescence immunoassay. However, instead of the most common metal complexes, such as Ru or Ir, the luminophore is luminol. The electrogenerated chemiluminescence of luminol was promoted by in situ electrochemical generation of hydrogen peroxide at a boron-doped diamond electrode. The electrochemical production of hydrogen peroxide was achieved in a carbonate solution by an oxidation reaction, while at the same time, microbeads labelled with luminol were deposited on the electrode surface. For the first time, we proved that was possible to obtain light emission from luminol without its direct oxidation at the electrode. This new emission mechanism is obtained at higher potentials than the usual luminol electrogenerated chemiluminescence at 0.3–0.5 V, in conjunction with hydrogen peroxide production on boron-doped diamond at around 2–2.5 V (vs Ag/AgCl).

#electrochemiluminescence,  #Microscopy, Electrode,  biosensors

N. Bagheri,    A. Chamorro,    A. Idili and  A. Porchetta

Toehold Switch DNA presenting a locked anti-PAM in the loop are designed to control Cas12a activity in response to different molecular  inputs.  The hairpin  to  duplex  reconfiguration  triggered  by  co-localization-based  displacement  reactions  provides  a means to control the accessibility of the PAM and as a consequence Cas12a activity. We demonstrate the rapid, one-pot detection of antibodies and small molecules with high sensitivity and specificity.

#Cas12,  #CRISPR  biosensors, #strand displacement reaction

A. Fiorani,    G. Valenti,    F. Paolucci and  Y. Einaga

Chem. Commun., 2023, 59, 7900 

The paper presents Boron Doped Diamond as new electrode for Electrochemiluminescence:

Boron-Doped Diamond (BDD) as an electrode material for ECL which has complementary properties compared to the most common metals (e.g., Au or Pt) and carbon materials (e.g., glassy carbon, carbon nanotubes and graphene). Boron-doped diamond electrodes emerged as novel electrodes, gaining more and more interest from the electrochemical community for their peculiar characteristics such as a wide solvent window, low capacitance, resistance to fouling and mechanical robustness.