A novel hydrogen peroxide biosensor based on the Sn–ZnNPs/MWNTs nanocomposite film

TiO2 nanoparticle modified organ-like Ti3C2 MXene nanocomposite encapsulating hemoglobin for a mediator-free biosensor with excellent performances

TiO2 nanoparticle modified organ-like Ti3C2 MXene (TiO2-Ti3C2) nanocomposite has been synthesized and then used to immobilize hemoglobin (Hb) to fabricate a mediator-free biosensor. The morphology and structure of TiO2-Ti3C2 nanocomposite were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Spectroscopic and electrochemical results revealed that TiO2-Ti3C2 nanocomposite is an excellent immobilization matrix with biocompatibility for redox protein, affording good protein bioactivity and stability. Due to the special organ-like hybrid structure of TiO2-Ti3C2, the direct electron transfer of Hb is facilitated and the prepared biosensors displayed good performance for the detection of H2O2 with a wide linear range of 0.1-380 μM for H2O2 (sensitivity of 447.3 μA mM(-1) cm(-2)), an extremely low detection limit of 14 nM for H2O2. Especially, numerous TiO2 nanoparticles with excellent biocompatibility on the surface of the nanocomposite may provide a protective microenvironment for Hb to make the prepared biosensor improve long-term stability. The TiO2-Ti3C2 based biosensor retains 94.6% of the initial response to H2O2 after 60-day storage. TiO2-Ti3C2 nanocomposite could be a promising matrix for the fabrication of mediator-free biosensors, and might find wide potential applications in environmental analysis and biomedical detection.

Review on Exhaled Hydrogen Peroxide as a Potential Biomarker for Diagnosis of Inflammatory Lung Diseases

Exhaled breath (EB) contains thousands of volatile and nonvolatile biomolecules. EB analysis is non-invasive and convenient to patients than blood or urine tests. The exhaled biomolecules have long been studied and recognized to have some potential biomarkers for diagnosis of diseases, evaluation of metabolic disorders and monitoring drug efficiency. For instance, Biomarkers such as exhaled hydrogen peroxide (H2O2) and exhaled nitric oxide are associated with inflammatory lung diseases, ammonia is used as a biomarker for kidney diseases and exhaled acetone is related to glucose concentration in blood and so it is used for diabetes diagnosis. H2O2 concentration in EB increases with the severity of lung diseases such as asthma, chronic obstructive pulmonary disease (COPD), and adult respiratory distress syndrome (ARDS). Different methods are used to measure H2O2 in exhaled breath condensate (EBC). In EBC the EB is collected in a condensate unit and then H2O2 concentration in the collected sample is detected using titrimetric, spectrophotometry, fluorescence, chemiluminescence and electrochemical sensors. Recently, some works have been done to measure the concentration of H2O2 in its vapor phase without a need for condensation units. The aim of this paper is to review and summarize the current methods being used to measure the concentration of H2O2 in EB to identify inflammatory lung diseases, and to discuss the advantages and disadvantages of these methods

Deep eutectic solvents: syntheses, properties and applications

Within the framework of green chemistry, solvents occupy a strategic place. To be qualified as a green medium, these solvents have to meet different criteria such as availability, non-toxicity, biodegradability, recyclability, flammability, and low price among others. Up to now, the number of available green solvents are rather limited. Here we wish to discuss a new family of ionic fluids, so-called Deep Eutectic Solvents (DES), that are now rapidly emerging in the current literature. A DES is a fluid generally composed of two or three cheap and safe components that are capable of self-association, often through hydrogen bond interactions, to form a eutectic mixture with a melting point lower than that of each individual component. DESs are generally liquid at temperatures lower than 100 °C. These DESs exhibit similar physico-chemical properties to the traditionally used ionic liquids, while being much cheaper and environmentally friendlier. Owing to these remarkable advantages, DESs are now of growing interest in many fields of research. In this review, we report the major contributions of DESs in catalysis, organic synthesis, dissolution and extraction processes, electrochemistry and material chemistry. All works discussed in this review aim at demonstrating that DESs not only allow the design of eco-efficient processes but also open a straightforward access to new chemicals and materials.