Electrochemical sensing platform based on kelp-derived hierarchical meso-macroporous carbons

In this paper, kelp (Laminaria japonica), as a kind of abundant biomass, is used as the precursor for the preparation of kelp-derived hierarchical meso-macroporous carbons (K-dHMMCs) through the carbonization under nitrogen (N2) atmosphere at high temperature. The K-dHMMCs exhibits the unique structure with high specific surface area of 416.02 m2 g-1, large pore volume of 0.24 cm3 g-1, the hierarchical meso-macroporous size distribution centered at 2, 12 and 82 nm and high density of defective sites, enabling K-dHMMCs attractive for the electrocatalysis. Drop-casting K-dHMMCs on the glassy carbon (GC) surface allows the construction of K-dHMMCs based electrochemical sensing platform, which shows electrocatalytic activities towards many electroactive molecules, such as potassium ferricyanide, nicotinamide adenine dinucleotide (NADH), hydrogen peroxide (H2O2), dopamine (DA), uric acid (UA), ascorbic acid (AA), epinephrine (EP), l-tyrosine (Tyr) and acetaminophen (APAP). Especially, the K-dHMMCs modified GC (K-dHMMCs/GC) electrode exhibits higher sensitivity, wider linear range, and lower detection limit than both carbon nanotubes modified GC (CNTs/GC) and GC electrodes for H2O2 detection, which makes the K-dHMMCs/GC electrode to be able to determine the H2O2 levels in human urine sample and monitor the H2O2 released from human cancer cells. These results demonstrate that K-dHMMCs/GC possesses a great potential for conventional electrochemical sensing applications.

Electrochemical Label-Free Nucleotide Sensors

Numerous researchers have devoted a great deal of effort over the last few decades to the development of electrochemical oligonucleotide detection techniques, owing to their advantages of simple design, inherently small dimensions, and low power requirements. Their simplicity and rapidity of detection makes label-free oligonucleotide sensors of great potential use as first-aid screening tools in the analytical field of environmental measurements and healthcare management. This review article covers label-free oligonucleotide sensors, focusing specifically on topical electrochemical techniques, including intrinsic redox reaction of bases, conductive polymers, the use of electrochemical indicators, and highly ordered probe structures.