Enantioselective recognition of electrochemically inactive phenylalanine by thiolated-cyclodextrin/ferrocene-coated gold nanoparticles

A Review on Electrochemical Sensors and Biosensors Used in Phenylalanine Electroanalysis

Phenylalanine is an amino acid found in breast milk and in many foods, being an essential nutrient. This amino acid is very important for the human body because it is transformed into tyrosine and, subsequently, into catecholamine neurotransmitters. However, there are individuals who were born with a genetic disorder called phenylketonuria. The accumulation of phenylalanine and of some metabolites in the body is dangerous and may cause convulsions, brain damage and mental retardation. Determining the concentration of phenylalanine in different biologic fluids is very important because it can provide information about the health status of the individuals envisaged. Since such determinations may be made by using electrochemical sensors and biosensors, numerous researchers have developed such sensors for phenylalanine detection and different sensitive materials were used in order to improve the selectivity, sensitivity and detection limit. The present review aims at presenting the design and performance of some electrochemical bio (sensors) traditionally used for phenylalanine detection as reported in a series of relevant scientific papers published in the last decade.

Application of Chiral Ionic Liquid-Modified Gold Nanoparticles in the Chiral Recognition of Amino Acid Enantiomers

Two chiral ionic liquids (ILs), namely 1-ethyl-3-methylimidazole l-tartrate (EMIML-Tar) and 1-ethyl-3-methylimidazole l-lactate (EMIML-Lac), were used to modify gold nanoparticles (AuNPs) for chiral recognition of amino acid enantiomers. Transmission electron microscopy, infrared spectroscopy, ultraviolet-visible spectroscopy, and capillary electrophoresis were used for the characterization of chiral IL-modified AuNPs. Meanwhile, the performance of l-tartaric acid and l-lactic acid as modifiers was investigated to make a comparison. The chiral recognition mechanism is further discussed.

Macroscopic switches constructed through host–guest chemistry

In this feature article, we discuss recent developments in macroscopic contact angle switches formed by different macrocyclic hosts and highlight the properties of these new functional surfaces and their potential applications.