Nanotechnology has opened new and exhilarating opportunities for exploring glucose biosensing applications of the newly prepared nanostructured materials. Nanostructured metal-oxides have been extensively explored to develop biosensors with high sensitivity, fast response times, and stability for the determination of glucose by electrochemical oxidation. This article concentrates mainly on the development of different nanostructured metal-oxide [such as ZnO, Cu(I)/(II) oxides, MnO₂, TiO₂, CeO₂, SiO₂, ZrO_2, and other metal-oxides] based glucose biosensors. Additionally, we devote our attention to the operating principles (i.e., potentiometric, amperometric, impedimetric and conductometric) of these nanostructured metal-oxide based glucose sensors. Finally, this review concludes with a personal prospective and some challenges of these nanoscaled sensors.

A fully integrated paper microfluidic electrochemical device equipped with three different cation permeable films is developed to determine blood ions (Cl⁻, Na⁺, K⁺, and Ca²⁺) at a time. These blood ions that are normally dissolved in the real human blood stream are essential for cell metabolisms and homeostasis in the human body. Abnormal concentration of blood ions causes many serious disorders. The optimized microfluidic device working without any external power source can directly and effectively separate human blood components, and subsequently detect a specific blood ion with minimized interference. The measured sensitivity to Cl⁻, K⁺, Na⁺, and Ca²⁺ are −47.71, 45.97, 51.06, and 19.46 in mV decade⁻¹, respectively. Potentiometric responses of the microfluidic devices to blood serum samples are in the normal ranges of each cation, and comparable with responses from the commercial blood ion analyzer Abbott i-Stat.

Airborne fungus, including Aspergillus species, is one of the major causes of human asthma. Conventional immunoassay or DNA-sequencing techniques, although widely used, are usually labor-intensive, time-consuming and expensive. In this paper, we demonstrate a sensor for the rapid detection of Aspergillus niger, a well-known allergenic fungal species, using single-walled carbon nanotube (SWNT) field effect transistors (FETs) functionalized with pentameric antibodies that specifically bind to Aspergillus species. This strategy resulted in the real time and highly sensitive and selective detection of Aspergillus due to an electrostatic gating effect from the Aspergillus fungus. This mechanism is in contrast to a previously reported Aspergillus sensor, which was based on mobility modulation from Aspergillus adsorption. Also, our sensor shows a much wider detection range from 0.5 pg mL⁻¹ to 10 μg mL⁻¹ with a lower detection limit of 0.3 pg mL⁻¹. The resulting SWNT-FET was able to selectively detect Aspergillus molds in the presence of more concentrated amounts of other mold species such as Alternaria alternata, Cladosporium cladosporioides, and Penicillium chrysogenum. We expect that our results can be used in real-time monitoring of the indoor air quality of a variety of public facilities for the elderly and children, who are more vulnerable to environmental biohazards.