Oligonucleotide-immobilized PEGylated black phosphorene with enhanced stability and activity for electrochemical...

The development of efficient, sensitive and rapid uranyl ion (UO₂²⁺) detection technology plays a critical role in promoting the utilization of uranium resources and protecting the environment. In this study, a novel composite of BP-mPEG-Olig was synthesized by immobilizing oligonucleotides (Oligs) on black phosphorene (BP), using maleimide-polyethylene glycol (mPEG) as both the linker and passivator. BP-mPEG-Olig utilizes the excellent electrical conductivity and high specific surface area of BP and the high affinity and molecular recognition capability of Oligs for electrochemical UO₂²⁺ sensing. Multiple material characterizations, including small-angle X-ray scattering, revealed the morphology and microstructures of BP-mPEG-Olig. The high electrochemical activity of BP-mPEG-Olig was achieved by abundant active reactions sites and rational charge transport. By systematically optimizing the detection conditions of differential pulse voltammetry, including electrode modification density, pH, temperature, and enrichment time, the developed electrochemical UO₂²⁺ sensor based on the BP-mPEG-Olig modified glassy carbon electrode demonstrated a linear detection range of 7.4 × 10^-8‒6.66 × 10^-7 M and a detection limit of 2.36 × 10^-10 M. The sensor showed good reproducibility and stability for real-world samples. The results indicate that post-graphene two-dimensional materials, represented by BP, have important prospects for the detection of trace uranium and other low-level radioactive elements where chemical sensors are applicable.