A multi-functional minimally-disruptive portable electrochemical system based on yeast/Co3O4/Au/SPEs for blood lead (II) measurement

Biological and technical challenges for implementation of yeast-based biosensors

Biosensors are low-cost and low-maintenance alternatives to conventional analytical techniques for biomedical, industrial and environmental applications. Biosensors based on whole microorganisms can be genetically engineered to attain high sensitivity and specificity for the detection of selected analytes. While bacteria-based biosensors have been extensively reported, there is a recent interest in yeast-based biosensors, combining the microbial with the eukaryotic advantages, including possession of specific receptors, stability and high robustness. Here, we describe recently reported yeast-based biosensors highlighting their biological and technical features together with their status of development, that is, laboratory or prototype. Notably, most yeast-based biosensors are still in the early developmental stage, with only a few prototypes tested for real applications. Open challenges, including systematic use of advanced molecular and biotechnological tools, bioprospecting, and implementation of yeast-based biosensors in electrochemical setup, are discussed to find possible solutions for overcoming bottlenecks and promote real-world application of yeast-based biosensors.

An overview of Structured Biosensors for Metal Ions Determination

The determination of metal ions is important for nutritional and toxicological assessment. Atomic spectrometric techniques are highly efficient for the determination of these species, but the high costs of acquisition and maintenance hinder the application of these techniques. Inexpensive alternatives for metallic element determination are based on dedicated biosensors. These devices mimic biological systems and convert biochemical processes into physical outputs and can be used for the sensitive and selective determination of chemical species such as cations. In this work, an overview of the proposed biosensors for metal ions determination was carried out considering the last 15 years of publications. Statistical data on the applications, response mechanisms, instrumentation designs, applications of nanomaterials, and multielement analysis are herein discussed.

Boosting sensitive and selective detection toward Pb(II) via activation effect of Co and orbital coupling between Pb and O over Co@Co3O4 nanocatalyst

Fruitful achievements on electrochemical detection toward Pb(II) have been achieved, and their good performance is generally attributed to the adsorption property of nanomaterials. However, the design of sensing interfaces from the electronic structure and electron transfer process is limited. Here, Co@Co₃O₄ acquired an ultra-high detection sensitivity of 103.11 µA µM^-1 toward Pb(II), outperforming the results previously reported. The interfacial oxygen atoms build an electron bridge for Co activating Co₃O₄. Particularly, new energy levels of oxygen atoms were generated and matched with that of Pb(II). The strong orbital coupling effect between O and Pb makes the Co@Co₃O₄ sensitive and selective toward Pb(II). Compared with Co metal and Co₃O₄, Pb(II) got more electrons from Co@Co₃O₄, and longer Pb-O bonds were formed, allowing more Pb(II) to be catalyzed and reduced. Also, the superior stability and reproducibility of electrochemical detection make electrodes practicably. This work reveals that metals can stimulate intrinsically catalytic activity of their metal oxides, with the generation of orbit energy levels that match to a specific analyte. It provides a promising strategy for constructing sensitive and selective sensing interfaces toward ultra-low concentration analyte in body fluid and other complex samples.