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The reversibility of the covalent interaction between boronic acids and 1,2- or 1,3-diols has put the spotlight on this reaction for its potential in the development of sensors and for the fishing of bioactive glycoconjugates. In this work, we describe the investigation of this reaction for the reversible functionalization of the surface of CdSe/ZnS Quantum Rods (QRs). With this in mind, we have designed a turn-off Förster resonance energy transfer (FRET) system that ensures monitoring the extent of the reaction between the phenyl boronic residue at the meso position of a BODIPY probe and the solvent-exposed 1,2-diols on QRs' surface. The reversibility of the corresponding boronate ester under oxidant conditions has also been assessed, thus envisioning the potential sensing ability of this system. [ABSTRACT FROM AUTHOR]

The quality of life of patients affected by Parkinson's disease is improved by medications containing levodopa and carbidopa, restoring the dopamine concentration in the brain. Accordingly, the affordable quality control of such pharmaceuticals is very important. Here is reported the simple and inexpensive colorimetric quantification of carbidopa in anti-Parkinson drugs by the selective condensation reaction between the hydrazine group from carbidopa and the formyl functional group of selected aldehydes in acidified hydroalcoholic solution. An optical assay was developed by using indole-3-carbaldehyde (I3A) giving a yellow aldazine in EtOH:H2O 1:1 (λmax~415 nm) at 70 °C for 4 h, as confirmed by LC-MS analysis. A filter-based plate reader was used for colorimetric data acquisition, providing superior results in terms of analytical performances for I3A, with a sensitivity ~50 L g−1 and LOD ~0.1 mg L−1 in comparison to a previous study based on vanillin, giving, for the same figures of merit values, about 13 L g−1 and 0.2–0.3 mg L−1, respectively. The calibration curves for the standard solution and drugs were almost superimposable, therefore excluding interference from the excipients and additives, with very good reproducibility (avRSD% 2–4%) within the linear dynamic range (10 mg L−1–50 mg L−1). [ABSTRACT FROM AUTHOR]

We used the first enzyme-free synthesis and stabilization of soluble melanochrome (MC) and 5,6-indolequinone (IQ) derived from levodopa (LD), dopamine (DA), and norepinephrine (NE) oxidation to develop a simple colorimetric assay for catecholamine detection in human urine, also elucidating the time-dependent formation and molecular weight of MC and IQ using UV–Vis spectroscopy and mass spectrometry. The quantitative detection of LD and DA was achieved in human urine using MC as a selective colorimetric reporter to demonstrate the potential assay applicability in a matrix of interest in therapeutic drug monitoring (TDM) and in clinical chemistry. The assay showed a linear dynamic range between 5.0 mg L−1 and 50.0 mg L−1, covering the concentration range of DA and LD found in urine samples from, e.g., Parkinson's patients undergoing LD-based pharmacological therapy. The data reproducibility in the real matrix was very good within this concentration range (RSDav% 3.7% and 6.1% for DA and LD, respectively), also showing very good analytical performances with the limits of detection of 3.69 ± 0.17 mg L−1 and 2.51 ± 0.08 mg L−1 for DA and LD, respectively, thus paving the way for the effective and non-invasive monitoring of dopamine and levodopa in urine from patients during TDM in Parkinson's disease. [ABSTRACT FROM AUTHOR]

We took advantage of the fluorescent features of a serotonin-derived fluorophore to develop a simple and low-cost assay for copper in urine. The quenching-based fluorescence assay linearly responds within the concentration range of clinical interest in buffer and in artificial urine, showing very good reproducibility (CVav% = 4% and 3%) and low detection limits (16 ± 1 μg L−1 and 23 ± 1 μg L−1). The Cu2+ content was also estimated in human urine samples, showing excellent analytical performances (CVav% = 1%), with a limit of detection of 59 ± 3 μg L−1 and a limit of quantification of 97 ± 11 μg L−1, which are below the reference value for a pathological Cu2+ concentration. The assay was successfully validated through mass spectrometry measurements. To the best of our knowledge, this is the first example of copper ion detection exploiting the fluorescence quenching of a biopolymer, offering a potential diagnostic tool for copper-dependent diseases. [ABSTRACT FROM AUTHOR]

Abnormal glycoconjugates have distinctly been recognized as potential biomarkers for cancer diagnosis. A great deal of attention has been focused on Tn antigen, an oversimplified mucin‐1 O‐glycan, over‐expressed in different cancers. Herein, we investigate the possibility to replace the use of anti‐Tn monoclonal antibodies with an innovative class of catecholamine‐based Molecularly Imprinted Polymers (MIPs), emerging in recent years as promising tools for bioanalytical applications. MIPs are synthetic receptors characterized by high sensitivity and specificity towards the imprinted target. Here, original polynorepinephrine‐based MIPs coupled to Surface Plasmon Resonance biosensing for Tn antigen recognition are reported. We have verified the imprinting and binding capacity of these MIPs towards very small antigenic entities, represented by the natural Tn antigen and the TnThr mimetic 1 (conjugated to BSA or linked to a MUC1 hexapeptide analogue), and compared the biosensor performances with an anti‐Tn monoclonal antibody. The results clearly display the effectiveness of the pursued imprinting strategies. [ABSTRACT FROM AUTHOR]