@article{nokey,

title = {Spectrophotometric determination of bisphenol A in beverages using multi-dispersion calibration},

author = {Vivian Maringolo and Alexandre Z. Carvalho and Paula Homem de Mello and Mateus Zanotto and Fernanda C.O.L. Martins and Wanessa R. Melchert and Diogo L. Rocha},

url = {https://www.sciencedirect.com/science/article/pii/S0956713524005681},

doi = {https://doi.org/10.1016/j.foodcont.2024.110851},

issn = {0956-7135},

year  = {2025},

date = {2025-02-01},

urldate = {2025-02-01},

journal = {Food Control},

volume = {168},

number = {110851},

abstract = {Bisphenol A (BPA) is an endocrine disruptor that may be present in plastics and coatings of food and beverage packages. In this regard, the World Health Organization recommends the maximum migration of BPA to foodstuffs as < 0.6 mg kg−1. Analytical BPA determination procedures have been based on chromatographic techniques, which generate waste with organic solvents. Alternatively, proposed spectrophotometric procedures have often shown high detection limits for foodstuffs analysis, requiring pre-concentration prior to determination. The analysis of beverages is susceptible to interferences because of their complex formulation comprising dyes and sugars, for example, that hinder spectrophotometric determinations. Multi-signal calibrations are powerful tools used to minimize matrix effects, and recently, they have proven efficient when performed in flow analysis systems, denominated as multi-dispersion calibration (MDC). This work proposes a multi-pumping flow system for the spectrophotometric determination of BPA based on the reaction with sulfanilamide (used for the first time) after diazotization to yield a compound with an absorption maximum at 446 nm. After the optimization of the main parameters, a linear response was observed between 0.25 and 10 mg L−1. The detection limit (by external calibration), coefficient of variation (n = 20), and determination rate were estimated at 0.11 mg L−1, 4.0 %, and 33 h−1, respectively. The MDC was exploited to analyze beverage samples to minimize interferences, especially due to dyes and sucrose. The detection limit estimated for this method was 0.057 mg L−1. Recoveries from 84 to 114 % and the agreement of comparative analysis of the samples with the reference procedure (at the 95% confidence level) demonstrated the accuracy of the proposed procedure. Therefore, the developed alternative is reliable with proper sensitivity and minimum sample preparation for the spectrophotometric determination of BPA in beverages.},

keywords = {},

pubstate = {forthcoming},

tppubtype = {article}

}

@article{nokey,

title = {Synthesis, photophysical properties, and photocytotoxic effects of porphyrin-diphenylalanine conjugates on HeLa cells},

author = {Sandra V. Vassiliades and Karina A.B. Argüello and Carlos E. Castro and Clovis A. Silva and Ana Clara Gonzalez and Paula Homem de Mello and Iseli Lourenço Nantes and Andrea M. Aguilar and Gustavo Barbosa Reis and Diogo Oliveira Silva and Francesca Giuntini and Wendel A. Alves},

url = {https://www.sciencedirect.com/science/article/pii/S0022286024030539},

doi = {https://doi.org/10.1016/j.molstruc.2024.140545},

issn = {0022-2860},

year  = {2024},

date = {2024-10-30},

urldate = {2024-10-30},

journal = {Journal of Molecular Structure},

volume = {1322},

number = {140545},

issue = {3},

abstract = {Photodynamic therapy (PDT) triggers selective cell death through intensive oxidative stress induced by the generation of reactive species by a photosensitizer (PS) excited by light. In this work, we report the synthesis of four novel porphyrins conjugated to the self-assembling dipeptide L,L-diphenylalanine (FF), effectively inhibiting cervical tumor cell growth. The PS were prepared using the classical A3B strategy, with functionalized and non-functionalized porphyrins obtained in moderate yields over 3 to 4 steps. Absorption and fluorescence studies indicate that the FF attached to the porphyrin ring influences their aggregation at micromolar concentrations. The compounds were efficiently internalized by HeLa cells after 4 h of incubation. Cytotoxicity tests performed in the 1.25–5.0 µmol L−1 range showed that cell viability was reduced to 70 % after irradiation (650 nm). A correlation between cell permeation and the cell death mechanism promoted by the porphyrin was observed.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Kraft lignin-based polyurethanes: Bulk properties, stability and adhesion to native aluminum surfaces},

author = {Demetrio J. dos Santos and Lara B. Tavares and Leonardo D. Antonino and Rogerio R. de Sousa Junior and Paula Homem de Mello and Cedric Rocha Leão},

url = {https://www.sciencedirect.com/science/article/pii/S0032386124007936},

doi = {https://doi.org/10.1016/j.polymer.2024.127457},

issn = {0032-3861},

year  = {2024},

date = {2024-09-12},

journal = {Polymer},

volume = {309},

number = {127457},

abstract = {Lignin as a byproduct from pulp and paper manufacturing has been extensively investigated as raw material for polymer developments. Although, fundamental topics related to the adhesion mechanisms of lignin-based reactive polyurethanes (LPU) still remain unclear. In this work, LPU thin films on native aluminum surface were prepared and characterized. Diluted in THF, employed as the solvent, reactive mixtures of 4,4′-methylene diphenyl isocyanate (4,4′-MDI) and the soluble fraction of three lignins (liquid hydroxypropylated Kraft lignin and two powder Kraft lignins with different pH) were used for LPU thin film deposition via spin coating on aluminum (PVD layer on silicon wafer). The resulting film thickness ranged from 8 nm to several micrometers. The chemical state of the three LPU compositions was assessed in bulk by infrared attenuated total reflectance (IR-ATR) and in the thin films by infrared external reflection absorption spectroscopy (IR-ERAS). Binding energies of 4,4′-methylene diphenyl diisocyanate with aliphatic and aromatic hydroxyl groups were estimated using Density Functional Theory (DFT) simulations. Thus, besides the elucidation of the bulk chemical state of LPUs, the relation to adhesion and stability of LPUs to a native aluminum surface was evaluated. In addition, film topography and homogeneity were monitored by SFM. All lignin types form uniform and homogeneous films. Results revealed a higher consumption of isocyanate groups (NCO) in the formulation with the alkaline Kraft lignin than with the acid one, despite its lower hydroxyl content. A gradient of unreacted NCO was observed in LPU thin films obtained with the powder Kraft lignin types. Residual NCO is also found in thicker films, while the thinnest films did not contain unreacted NCO anymore, indicating the activating effect of the native aluminum surface on LPU formation.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Design Bioinspirado de Corantes},

author = {Paula Homem de Mello and Ana Clara Gonzalez de Souza and Diêgo Ulysses Melo and Gabriel S Mol and Jhonathan Rosa de Souza and Leonardo M Carneiro and Maíra G Nobrega and Mateus Zanotto and Raissa Lohanna GQ Corrêa and Hueder PM de Oliveira and Fernando H Bartoloni and Yuri A Aoto and Mauricio D. Coutinho Neto and Ednilsom Orestes},

url = {https://www.scielo.br/j/qn/a/RCr5ZtRt4bVGwZhp5nxGSjP},

doi = {https://doi.org/10.21577/0100-4042.20250047},

year  = {2024},

date = {2024-09-06},

urldate = {2024-09-06},

journal = {Química Nova},

volume = {48},

issue = {3},

pages = {e-20250047},

publisher = {Sociedade Brasileira de Química},

abstract = {The history of the discovery, use, and development of dyes is closely linked to the history of humanity itself. Among the first records of human civilization are cave paintings made from, e.g., fruits, plants, minerals, and insects. Over the centuries, using different techniques, colors have been given to all types of materials and products, from clothing to food. The chemicals responsible for colors are dyes - a vast collection of molecules of the most varied compositions, but which have in common the absorption of light within the visible window of the electromagnetic spectrum. This article aims not only to review the properties of some classes of natural dyes, their origins, and their applications but also to describe the various computational chemistry methods involved in designing new bio-inspired molecules.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Chemiluminescence of a Firefly Luciferin Analogue Reveals that Formation of the Key Intermediate Responsible for Excited State Generation Occurs on a Fully Concerted Step},

author = {Diego Ulysses Melo and Henrique Bergonzini de Lima and Roberta Albino Reis and Andreia Boaro and Alexander Garreta Gonçalves Costa Pinto and Luiz Francisco Monteiro Leite Ciscato and Paula Homem de Mello and Fernando H Bartoloni},

url = {https://pubs.acs.org/doi/full/10.1021/acs.joc.3c02079},

doi = {10.1021/acs.joc.3c02079},

year  = {2023},

date = {2023-12-19},

urldate = {2023-12-19},

journal = {The Journal of Organic Chemistry},

volume = {89},

issue = {1},

pages = {345-355},

abstract = {The chemiluminescence (CL) reaction of eight different 2-(4-hydroxyphenyl)-4,5-dihydrothiazole-4-carboxylate esters with an organic superbase and oxygen was investigated through a kinetic and computational study. These esters are all analogues to the luciferin substrate involved in efficient firefly bioluminescence. The kinetic data obtained from CL emission and light absorption assays were used in the context of linear free energy relationships (LFER); we obtained the Hammett reaction constant ρ = +1.62 ± 0.09 and the Brønsted constant βlg = −0.39 ± 0.04. These observations from LFER, together with activation parameters obtained from Arrhenius plots, suggest that the formation of the high-energy intermediate (HEI) 1,2-dioxetanone occurs via a concerted mechanism during the rate-determining step of the reaction. Calculations performed using density functional theory support a late transition state for HEI formation within the reaction mechanism pathway, which was described considering geometric parameters, Wiberg bond indices from natural bond order analysis, and the atomic charges derived from the electrostatic potential.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Synergistic Interaction of Hyperbranched Polyglycerols and Cetyltrimethylammonium Bromide for Oil/Water Interfacial Tension Reduction: A Molecular Dynamics Study},

author = {James M. de Almeida and Conny Cerai Ferreira and Lucas Bandeira and Renato D Cunha and Mauricio D. Coutinho Neto and Paula Homem De Mello and Ednilsom Orestes and Regina Sandra Veiga Nascimento},

url = {https://pubs.acs.org/doi/full/10.1021/acs.jpcb.3c01707},

doi = {10.1021/acs.jpcb.3c01707},

year  = {2023},

date = {2023-10-23},

urldate = {2023-12-23},

journal = {The Journal of Physical Chemistry B},

volume = {127},

issue = {43},

pages = {9356-9365},

abstract = {Applying surfactants to reduce the interfacial tension (IFT) on water/oil interfaces is a proven technique. The search for new surfactants and delivery strategies is an ongoing research area with applications in many fields such as drug delivery through nanoemulsions and enhanced oil recovery. Experimentally, the combination of hyperbranched polyglycerol (HPG) with cetyltrimethylammonium bromide (CTAB) substantially reduced the observed IFT of oil/water interface, 0.9 mN/m, while HPG alone was 5.80 mN/m and CTAB alone IFT was 8.08 mN/m. Previous simulations in an aqueous solution showed that HPG is a surfactant carrier. Complementarily, in this work, we performed classical molecular dynamics simulations on combinations of CTAB and HPG with one aliphatic chain to investigate further the interaction of this pair in oil interfaces and propose the mechanism of IFT decrease. Basically, from our results, one can observe that the IFT reduction comes from a combination of effects that have not been observed for other dual systems: (i) Due to the CTAB-HPG strong interaction, a weakening of their specific and isolated interactions with the water and oil phases occurs. (ii) Aggregates enlarge the interfacial area, turning it into a less ordered interface. (iii) The spread of individual molecules charge profiles leads to the much lower interfacial tension observed with the CTAB+HPG systems.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Benchmarking DFT functionals for photophysics of pyranoflavylium cations},

author = {Jhonathan Rosa de Souza and Carles Curutchet and Yuri A Aoto and Paula Homem de Mello},

url = {https://www.sciencedirect.com/science/article/pii/S109332632300058X},

doi = {10.1016/j.jmgm.2023.108460},

issn = {1093-3263},

year  = {2023},

date = {2023-07-01},

urldate = {2023-07-01},

journal = {Journal of Molecular Graphics and Modelling},

volume = {122},

number = {108460},

abstract = {An intense absorption, phosphorescence, a long triplet excited state lifetime and singlet oxygen generation capabilities are characteristics of pyranoflavylium cations, analogues to pyranoanthocyanidins originated in the maturation process of red wine. Such properties make these compounds potential photosensitizers to be applied in photodynamic therapy. In this context, the photophysical processes underlying that treatment critically depend on the electronic structure of the pyranoflavylium molecules. When employing density functional theory to describe the electronic structure of molecules, the choice of the most suitable functional is not trivial, and benchmark studies are needed to orient practitioners in the field. In this work, a benchmark of seven of the most commonly used density functionals in addressing the photophysical properties of a set of eight pyranoflavylium cations is reported. Ground and excited state geometries, molecular orbitals, and absorption, fluorescence and phosphorescence transition energies were calculated using density functional theory approaches, and evaluated and compared to experimental data and monoreferential wave function-based methodologies. Statistical analysis of the results indicates that global-hybrid functionals allow an excellent description of absorption and emission energies, with errors around 0.05 eV, while range-separated variants led to somewhat larger errors in the range 0.1–0.2 eV. In contrast, range-separated functionals display excellent phosphorescence energies with errors close to 0.05 eV, in this case global-hybrids showing increased discrepancies around 0.5–0.1 eV.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Diving into the optoelectronic properties of Cu (II) and Zn (II) curcumin complexes: a DFT and wavefunction benchmark},

author = {Raissa Lohanna GQ Corrêa and Matheus Morato Ferreira de Moraes and Kléber Thiago de Oliveira and Yuri A. Aoto and Mauricio D. Coutinho Neto and Paula Homem de Mello},

url = {https://link.springer.com/article/10.1007/s00894-023-05560-1},

doi = {10.1007/s00894-023-05560-1},

year  = {2023},

date = {2023-04-29},

urldate = {2023-04-29},

journal = {Journal of Molecular Modelling},

volume = {29},

number = {166},

abstract = {Context

Curcumin is a popular food additive around the world whose medicinal properties have been known since ancient times. The literature has recently highlighted several biological properties, but besides the health-related usages, its natural yellowish color may also be helpful for light-harvesting applications. This research aims to close a knowledge gap regarding the photophysical description of curcumin and its metallic complexes.

Methods

We conducted benchmark experiments comparing NEVPT calculations with several DFT functionals (B3LYP, M06-L, M06-2X, CAM-B3LYP, and ωB97X-D) for describing the UV spectra of curcumin and its metallo-derivative, curcumin-copper(II). Once we determined the most suitable functional, we performed tests with different basis sets and conditions, such as solvation and redox state, to identify their impact on excited state properties. These results are also reported for the curcumin-zinc(II) derivative. We found that the accuracy of DFT functionals depends strongly on the nature of curcumin’s excitations. Intra-ligand transitions dominate the absorption spectra of the complexes. Curcumin absorption is marginally affected by solvation and chelation, but when combined with redox processes, they may result in significant modifications. This is because copper cation changes its coordination geometry in response to redox conditions, changing the spectrum. We found that, compared to a NEVPT reference, B3LYP is the best functional for a general description of the compounds, despite not being appropriate for charge transfer transitions. M06-L was the best for LMCT transitions. However, compared with NEVPT2 and PNO-LCCSD(T)-F12 results, no functional achieved acceptable accuracy for MLCT transitions.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}