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This research was funded by Compra Publica Precomercial, Reference 2012/000069, Ministerio de Economia y Competitividad, Espana. ONCOVER project: Volatile compound detection system for early cancer diagnosis., Enzyme-linked immunosorbent assay (ELISA) is routinely used to detect biomolecules related to several diseases facilitating diagnosis and monitoring of these, as well as the possibility of decreasing their mortality rate. Several methods have been carried out to improve the ELISA sensitivity through antibodies immobilization on the microtiter plates. Here, we have developed a strategy of antibodies immobilization to improve the ELISA sensitivity increasing the antibody density surface through the tetrazine (Tz)-trans-cyclooctene (TCO) reaction. For this, we prepared surfaces with tetrazine groups while the captured antibody was conjugated with TCO. The tetrazine surfaces were prepared in two different ways: (1) from aminated plates and (2) from Tz-BSA-coated plates. The surfaces were evaluated using two sandwich ELISA models, one of them using the low-affinity antibody anti-c-myc as a capture antibody to detect the c-myc-GST-IL8h recombinant protein, and the other one to detect the carcinoembryonic human protein (CEA). The sensitivity increased in both surfaces treated with tetrazine in comparison with the standard unmodified surface. The c-myc-GST-IL8h detection was around 10-fold more sensible on both tetrazine surfaces, while CEA ELISA detection increased 12-fold on surfaces coated with Tz-BSA. In conclusion, we show that it is possible to improve the ELISA sensitivity using this immobilization system, where capture antibodies bond covalently to surfaces., Compra Publica Precomercial, Ministerio de Economia y Competitividad, Espana 2012/000069

This research was funded by Agencia Estatal de Investigacion, Ministerio de Ciencia, Innovacion y Universidades (MICIU) from Spain, and was co-funded by FEDER-EU (project nos. PGC2018-102047-B-I00 and CTQ2017-85821-R), Junta de Andalucia (research group FQM-283), and University of Granada (project ref. PPJIA2019-03)., The contributions of the undergraduate student Patricia Quirantes-Gualda and the technical and human support from SGIker (UPV/EHU) are gratefully acknowledged., In the extensive field of metal ions, their interactions with nucleic acids, and their constituents, the main aim of this work is to develop a metal chelate suitable to recognize two molecules of an adenine nucleoside. For this purpose, the dinuclear chelate Cu-2 (mu-EDTA) (ethylenediaminetetraacetate(4-) ion (EDTA)) is chosen as a bicephalic receptor model for N9-(2-hydroxyethyl)adenine (9heade). A one-pot synthesis is reported to obtain the compound [Cu-2(mu(2)-EDTA)(9heade)(2)(H2O)(4)]center dot 3H(2)O, which has been characterized by single-crystal X-ray diffraction and various spectral, thermal, and magnetic methods. The complex unit is a centro-symmetric molecule, where each Cu (II) center is chelated by a half-EDTA, and is further surrounded by an N7-dentate 9heade nucleoside and two non-equivalent trans-O-aqua molecules. The metal chelate-nucleoside molecular recognition is referred to as an efficient cooperation between the Cu-N7(9heade) coordination bond and a (9heade)N6-H center dot center dot center dot O(carboxyl, EDTA) interligand interaction. Theoretical calculations are also made to account for the relevance of this interaction. The extreme weakness with which each water molecule binds to the metal center disturbs the thermal stability and the infrared (FT-IR) and electron spin resonance (ESR) spectra of the compound., Agencia Estatal de Investigacion, Ministerio de Ciencia, Innovacion y Universidades (MICIU) from Spain, European Commission PGC2018-102047-B-I00 CTQ2017-85821-R, Junta de Andalucia, University of Granada PPJIA2019-03

Three mixed-ligands of Cd(II) coordination polymers were unintentionally obtained: {[Cd(&micro, 3-EDTA)(Him)&middot, Cd(Him)(H2O)2]&middot, H2O}n (1), {[Cd(&micro, 4-CDTA)(Hade)&middot, Cd(Hade)2]}n (2), and {[Cd(&micro, 3-EDTA)(H2O)&middot, Cd(H9heade)(H2O)]&middot, 2H2O}n (3), having imidazole (Him), adenine (Hade) or 9-(2-hydroxyethyl)adenine (9heade) as the N-heterocyclic coligands. Compounds 2 and 3 were obtained by working with an excess of corresponding N-heterocyclic coligands. The single-crystal X-ray diffraction structures and thermogravimetric analyses are reported. The chelate moieties in all three compounds exhibit hepta-coordinated Cd centers, whereas the non-chelated Cd center is five-coordinated in 1 and six-coordinated in 2 and 3. Him and Hade take part in the seven-coordinated chelate moieties in 1 and 2, respectively. In contrast, 9heade is unable to replace the aqua ligand of the chelate [Cd (EDTA) (H2O)] moiety in 3. The thermogravimetric analysis (TGA) behavior of [Cd (H2EDTA) (H2O)]&middot, 2H2O in 1 and 3 leads to a residue of CdO, whereas the N-rich compound 2 yields CdO&middot, Cd(NO3)2 as a residue. Density functional theory (DFT) calculations along with molecular electrostatic potential (MEP) and quantum theory of atoms-in-molecules computations were performed in adenine (compound 2) and (2-hydroxyethyl)adenine (compound 3) to analyze how the strength of the H-bonding and &pi, stacking interactions, respectively, are affected by their coordination to the Cd-metal center.