Chromatographic methods are increasingly being used for the quantitative determination of endogenous compounds in biological samples. This article presents an overview of the specific issues, which have to be taken into account for the development, validation and application of these methods. The usual lack of analyte-free samples of the biological matrix implies that alternative strategies for...

This work introduces the concept of multi-analyte biomarkers for continuous metabolic monitoring. The importance of using more than one marker lies in the ability to obtain a holistic understanding of the metabolism. This is showcased for the detection and prediction of exhaustion during intense physical exercise. The findings presented here indicate that when glucose and lactate changes over t...

A variety of mechanisms have been proposed for detecting inorganic ions using magnetic resonance imaging (MRI) contrast agents. In the most widely explored approach, analyte binding to a paramagnetic metal chelate withdraws ligand(s), increasing the number (q) of inner sphere sites available for water coordination at the paramagnetic center. As a consequence, the longitudinal relaxivity (r1) of...

A new immunometric two-site sandwich assay is introduced, in which a label-scavenging binding partner is added to the sample in addition to the analyte-binding partner. The scavenger binding partner binds excess label antibody, giving a signal proportional to the amount of excess label antibody in the sample solution. A set of two calibration curves is obtained from the two binding partners sim...

One of the current limitations surrounding surface-enhanced Raman scattering (SERS) is the perceived lack of reproducibility. SERS is indeed challenging, and for analyte detection, it is vital that the analyte interacts with the metal surface. However, as this is analyte dependent, there is not a single set of SERS conditions that are universal. This means that experimental optimisation for opt...

Chemical sensing properties of phthalocyanine thin-film transistors have been investigated using nearly identical n- and p-channel devices. P-type copper phthalocyanine (CuPc) has been modified with fluorine groups to convert the charge carriers from holes to electrons. The sensor responses to the tight binding analyte dimethyl methylphosphonate (DMMP) and weak binding analyte methanol (MeOH) w...

In this work surface-enhanced resonance Raman spectroscopic experiments have demonstrated that metallic single-walled carbon nanotubes can be used as chemical assemblies between the pyrene analyte and the silver colloidal surface. Pyrene has been detected at concentrations lower than 10(-9) M by use of the 514.5 nm excitation laser line. A charge transfer from the surface to the nanotube charac...

In this study an attempt has been made to explain the reasons for changing the enantioseparation selectivity in some dual cyclodextrin (CD) systems compared to the use of single chiral selectors in capillary electrophoresis (CE). An explanation for selectivity changes is proposed based on the effect of the chiral selector on the mobility of the analyte. In order to support the proposed mechanis...

This paper deals with the dynamic modeling, analysis, 4 and statistical signal processing of the ion channel switch biosen5 sor. The electrical dynamics are described by a second-order linear 6 system. The chemical kinetics of the biosensor response to analyte 7 concentration in the reaction-rate-limited regime are modeled by 8 a two-timescale nonlinear system of differential equations. Also, 9...

Enzyme-based chemical biosensors are based on biological recognition. In order to operate, the enzymes must be available to catalyze a specific biochemical reaction and be stable under the normal operating conditions of the biosensor. Design of biosensors is based on knowledge about the target analyte, as well as the complexity of the matrix in which the analyte has to be quantified. This artic...