Passivation of black phosphorus as organic-phase enzyme platform for bisphenol A determination

Ultrasensitive Electrochemical Aptasensing of Malathion Based on Hydroxylated Black Phosphorus/Poly-L-Lysine Composite

A highly sensitive unlabeled electrochemical aptasensor based on hydroxylated black phosphorus/poly-L-lysine (hBP/PLL) composite is introduced herein for the detection of malathion. Poly-L-lysine (PLL) with adhesion and coating properties adhere to the surface of the nanosheets by noncovalent interactions with underlying hydroxylated black phosphorus nanosheets (hBP) to produce the hBP/PLL composite. The as-synthesized hBP/PLL composite bonded to Au nanoparticles (Au NPs) firmly by assembling and using them as a substrate for the aptamer with high specificity as a probe to fabricate the sensor. Under optimal conditions, the linear range of the electrochemical aptasensor was 0.1 pM~1 μM, and the detection limit was 2.805 fM. The electrochemical aptasensor has great selectivity, a low detection limit, and anti-interference, which has potential application prospects in the field of rapid trace detection of pesticide residues.

Recent advances in black phosphorus-based electrochemical sensors: A review

Since the discovery of liquid-phase-exfoliated black phosphorus (BP) as a field-effect transistor in 2014, BP, with its 2D layered structure, has attracted significant attention, owing to its anisotropic electroconductivity, tunable direct bandgap, extraordinary surface activity, moderate switching ratio, high hole mobility, good biocompatibility, and biodegradability. Several pioneering research efforts have explored the application of BP in different types of electrochemical sensors. This review summarizes the latest synthesis methods, protection strategies, and electrochemical sensing applications of BP and its derivatives. The typical synthesis methods for BP-based crystals, nanosheets, and quantum dots are discussed in detail; the degradation of BP under ambient conditions is introduced; and state-of-the-art protection methodologies for enhancing BP stability are explored. Various electrochemical sensing applications, including chemically modified electrodes, electrochemiluminescence sensors, enzyme electrodes, electrochemical aptasensors, electrochemical immunosensors, and ion-selective electrodes are discussed in detail, along with the mechanisms of BP functionalization, sensing strategies, and sensing properties. Finally, the major challenges in this field are outlined and future research avenues for BP-based electrochemical sensors are highlighted.

Polyphenol oxidase-based electrochemical biosensors: A review

The detection of phenolic compounds is relevant not only for their possible benefits to human health but also for their role as chemical pollutants, including as endocrine disruptors. The required monitoring of such compounds on-site or in field analysis can be performed with electrochemical biosensors made with polyphenol oxidases (PPO). In this review, we describe biosensors containing the oxidases tyrosinase and laccase, in addition to crude extracts and tissues from plants as enzyme sources. From the survey in the literature, we found that significant advances to obtain sensitive, robust biosensors arise from the synergy reached with a diversity of nanomaterials employed in the matrix. These nanomaterials are mostly metallic nanoparticles and carbon nanostructures, which offer a suitable environment to preserve the activity of the enzymes and enhance electron transport. Besides presenting a summary of contributions to electrochemical biosensors containing PPOs in the last five years, we discuss the trends and challenges to take these biosensors to the market, especially for biomedical applications.