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[EN] A simple colorimetric probe for the selective and sensitive detection of neurotransmitter norepinephrine (NE), an important biomarker in the detection of tumors such as pheochromocytoma and paraganglioma, is described. The sensing strategy is based on the use of spherical gold nanoparticles functionalized with benzaldehyde and boronic acid-terminated moieties. A double molecular recognition involving on one hand the aromatic aldehyde and the aminoalcohol group of NE, and on the other hand the boronic acid and the catechol moiety of the neurotransmitter, results in analyte triggered aggregation of the gold nanoparticles, leading to a bathochromic shift of the SPR band in the UV-vis spectrum of the probe and a clear change in the color of the solution from red to blue. Probe P1 shows a remarkable selectivity toward NE versus other catecholamine neurotransmitters (dopamine and epinephrine) and selected biomolecules (S-HIAA, L-Tyr, glucose, uric acid, Lys and glutamic acid). Moreover, a linear response to NE in the 0-1 mu M concentration range was observed and a limit of detection of 0.07 mu M in aqueous media was determined by UV-vis spectroscopy. The sensitivity of the probe toward NE in synthetic urine was also evaluated. In this medium, a limit of detection of 0.09 mu M was obtained which falls within the range of clinical interest, Financial support from the Spanish Government (Projects MAT2015-64139-C4-1-R and MAT2015-64139-C4-4-R) and the Generalitat Valencia (Projects PROMETEOII/2014/047 and AICO/2017/093) is gratefully acknowledged. T. Godoy-Reyes is grateful to the Generalitat Valenciana for her Santiago Grisolia fellowship.

We report herein a L-glutamate (L-Glu)-responsive delivery system. It consists of Janus Au–mesoporous silica (MS) nanoparticles functionalized with L-glutamate oxidase on the Au face and with self-immolative arylboronate derivatives as caps on the MS face. The MS face is additionally loaded with a cargo. The delivery paradigm is based on the recognition of L-Glu by the enzyme and the subsequent formation of H2O2, which induces the cleavage of the self-immolative gate and the uncapping of the pores. Given the importance of L-Glu as a key neurotransmitter, we hope that these findings will help in designing new therapeutic strategies for nervous system diseases.

In nature, coordinated communication between different entities enables a group to accomplish sophisticated functionalities that go beyond those carried out by individual agents. The possibility of programming and developing coordinated communication networks at the nanoscale—based on the exchange of chemical messengers—may open new approaches in biomedical and communication areas. Here, a stimulus-responsive circular model of communication between three nanodevices based on enzyme-functionalized Janus Au–mesoporous silica capped nanoparticles is presented. The output in the community of nanoparticles is only observed after a hierarchically programmed flow of chemical information between the members., A community of three nanodevices communicates through a hierarchically programmed circular flow of chemical information between members.

[EN] Mesoporous silica nanoparticles capped with acetylcholinesterase, through boronic ester linkages, selectively release an entrapped cargo in the presence of acetylcholine., The authors acknowledge financial support from the Spanish Government (MAT2015-64139-C4-1-R, MAT2015-64139-C4-4-R and AGL2015-70235-C2-2-R) and the Generalitat Valenciana (PROMETEO2018/024). T. Godoy-Reyes is grateful to Generalitat Valenciana for her Santiago Grisollía fellowship. A. García-Fernández is grateful to the Spanish Government for her FPU fellowship

[EN] A simple and effective colorimetric method for the detection of normetanephrine (NMN), an O-methylated metabolite of norepinephrine, using functionalised gold nanoparticles is described. This metabolite is an important biomarker in the diagnosis of adrenal tumours such as pheocromocytoma or paraganglioma. The colorimetric probe consists of spherical gold nanoparticles (AuNPs) functionalised with two different ligands, which specifically recognize different functional groups in normetanephrine. Thus, a benzaldehyde-terminated ligand was used for the recognition of the amino alcohol moiety in NMN, by forming the corresponding oxazolidine. On the other hand, N-acetyl-cysteine was chosen for the recognition of the phenolic hydroxyl group through the formation of hydrogen bonds. The selective double molecular recognition between the probe and the hydroxyl and the amino-alcohol moieties of normetanephrine led to interparticle-crosslinking aggregation resulting in a change in the color of the solution, from red to blue, which could be observed by naked eye. The probe was highly selective towards normetanephrine and no color changes were observed in the presence of other neurotransmitter metabolites such as homovanillic acid (HVA) (dopamine metabolite), 5-hydroxyindoleacetic acid (5-HIAA) (serotonin metabolite), or other biomolecules present in urine such as glucose (Glc), uric acid (U.A), and urea. Finally, the probe was evaluated in synthetic urine with constituents that mimic human urine, where a limit of detection of 0.5 mu M was achieved., Financial support from the Spanish Government (project MAT2015-64139-C4) and Generalitat Valenciana (Project PROMETEOII/2014/047 and AICO/2017/093) is gratefully acknowledged. T. Godoy-Reyes is grateful to Generalitat Valenciana for her Santiago Grisolia fellowship.

[EN] We report a simple, sensitive and selective method for the colorimetric detection of serotonin (5-HT) in aqueous media using bifunctionalized gold nanoparticles (AuNPs). The probe (1) consisted of AuNPs functionalised with dithiobis(succinimidylpropionate) (DSP) and N-acetyl-l-cysteine (NALC). DSP was chosen to react with the amino group of 5-HT, whereas NALC was chosen to bind the hydroxyl group in 5-HT through hydrogen bonding and electrostatic interactions. A double interaction between nanoparticles and the hydroxyl and the amino group of serotonin led to interparticle-crosslinking aggregation. This, resulted in a colour change from red to blue that can be observed by the naked eye. The probe was selective to 5-HT and no colour modulation was observed in the presence of other neurotransmitters (i.e. dopamine, epinephrine, norepinephrine), selected biomolecules (i.e. L-tyrosine, gamma-aminobutyric acid, L-cysteine, uric acid, oxalic acid, aspartic acid and glutamic acid) and common inorganic species. A limit of detection as low as 0.1 mu M was determined in buffered water at pH 7 by UV-vis titrations. Similar response of the probe to 5-HT was observed in simulated blood serum, with a limit of detection of 0.12 mu M, and a linear response within the 0-3 mu M concentration range, which is within the range of the 5-HT concentrations of clinical interest. Finally, the performance of probe (1) in real human blood samples was evaluated, and showed a remarkable ability to distinguish between normal 5-HT levels and 5-HT levels indicative of disease. (c) 2017 Elsevier B.V. All rights reserved., Financial support from the Spanish Government (Projects MAT2015-64139-C4-1-R and MAT2015-64139-C4-4-R) and the Generalitat Valenciana (Project PROMETEOII/2014/047) is gratefully acknowledged. T. Godoy-Reyes is grateful to the Generalitat Valenciana for her Santiago Grisolia fellowship. A. Llopis-Lorente thanks "La Caixa" Banking Foundation for his PhD grant. SCSIE (Universitat de Valencia) is gratefully acknowledged for all the equipment employed. NMR was registered at the U26 facility of ICTS "NANBIOSIS" at the Universitat de Valencia. Support from the Juana Portaceli Health Centre of the Universitat Politecnica de Valencia to obtain blood samples from a healthy volunteer is gratefully acknowledged.