Essential oils (EO) obtained from plants have proven industrial applications in the manufacturing of perfumes and cosmetics, in the production and flavoring of foods and beverages, as therapeutic ...agents in aromatherapy, and as the active principles or excipients of medicines and pharmaceutics due to their olfactory, physical-chemical, and biological characteristics. On behalf of the new paradigm of a more natural and sustainable lifestyle, EO are rather appealing due to their physical, chemical, and physiological actions in human beings. However, EO are unstable and susceptible to degradation or loss. To tackle this aspect, the encapsulation of EO in microporous structures as zeolites is an attractive solution, since these host materials are cheap and non-toxic to biological environments. This overview provides basic information regarding essential oils, including their recognized benefits and functional properties. Current progress regarding EO encapsulation in zeolite structures is also discussed, highlighting some representative examples of essential oil delivery systems (EODS) based on zeolites for healthcare applications or aromatherapy.
Fluorescence-based probes represent a powerful tool for noninvasive imaging of living systems in real time and with a high temporal and spatial resolution. Amongst several known fluorophores, ...3-difluoroborodipyrromethene (BODIPY) derivatives have become a cornerstone for innovative fluorescent labelling applications, mainly due to their advantageous features including their facile synthesis, structural versatility and exceptional photophysical properties. In this context, we report a BODIPY-based fluorescent probe for imaging of lysosomes in living cells. The BODIPY derivative displayed a remarkable fluorescence enhancement at low pH values with a pK
* of 3.1. In vitro studies by confocal microscopy in HeLa cells demonstrated that the compound was able to permeate cell membrane and selectively label lysosome whilst remaining innocuous to the cell culture at the maximum concentration tested. Herein, the BODIPY derivative holds the promise of investigating lysosomal dynamics and function in living cells through fluorescence imaging.
Bearing in mind the interest in the development and application of amino acids/peptides as bioinspired systems for sensing, a series of new phenylalanine derivatives bearing thiosemicarbazone and ...hydrazone units at the side chain were synthesised and evaluated as fluorimetric chemosensors for ions. Thiosemicarbazone and hydrazone moieties were chosen because they are considered both proton-donor and proton-acceptor, which is an interesting feature in the design of chemosensors. The obtained compounds were tested for the recognition of organic and inorganic anions (such as AcO−, F−, Cl−, Br−, I−, ClO4−, CN−, NO3−, BzO−, OH−, H2PO4− and HSO4−) and of alkaline, alkaline-earth, and transition metal cations, (such as Na+, K+, Cs+, Ag+, Cu+, Cu2+, Ca2+, Cd2+, Co2+, Pb2+, Pd2+, Ni2+, Hg2+, Zn2+, Fe2+, Fe3+ and Cr3+) in acetonitrile and its aqueous mixtures in varying ratios via spectrofluorimetric titrations. The results indicate that there is a strong interaction via the donor N, O and S atoms at the side chain of the various phenylalanines, with higher sensitivity for Cu2+, Fe3+ and F− in a 1:2 ligand-ion stoichiometry. The photophysical and metal ion-sensing properties of these phenylalanines suggest that they might be suitable for incorporation into peptide chemosensory frameworks.
Industrial activity has raised significant concerns regarding the widespread pollution caused by metal ions, contaminating ecosystems and causing adverse effects on human health. Therefore, the ...development of sensors for selective and sensitive detection of these analytes is extremely important. In this regard, an azo dye, Dabcyl 2, was synthesised and investigated for sensing metal ions with environmental and industrial relevance. The cation binding character of 2 was evaluated by colour changes as seen by the naked eye, UV-Vis and 1H NMR titrations in aqueous mixtures of SDS (0.02 M, pH 6) solution with acetonitrile (99:1, v/v). Out of the several cations tested, chemosensor 2 had a selective response for Pd2+, Sn2+ and Fe3+, showing a remarkable colour change visible to the naked eye and large bathochromic shifts in the UV-Vis spectrum of 2. This compound was very sensitive for Pd2+, Sn2+ and Fe3+, with a detection limit as low as 5.4 × 10−8 M, 1.3 × 10−7 M and 5.2 × 10−8 M, respectively. Moreover, comparative studies revealed that chemosensor 2 had high selectivity towards Pd2+ even in the presence of other metal ions in SDS aqueous mixtures.
Leishmaniasis and Human African trypanosomiasis pose significant public health threats in resource-limited regions, accentuated by the drawbacks of the current antiprotozoal treatments and the lack ...of approved vaccines. Considering the demand for novel therapeutic drugs, a series of BODIPY derivatives with several functionalizations at the
, 2 and/or 6 positions of the core were synthesized and characterized. The in vitro activity against
and
parasites was carried out alongside a human healthy cell line (MRC-5) to establish selectivity indices (SIs). Notably, the
-substituted BODIPY, with 1-dimethylaminonaphthalene (
) and anthracene moiety (
), were the most active against
, displaying IC
= 4.84 and 5.41 μM, with a 16 and 18-fold selectivity over MRC-5 cells, respectively. In contrast, the mono-formylated analogues
and
exhibited the highest toxicity (IC
= 2.84 and 6.17 μM, respectively) and selectivity (SI = 24 and 11, respectively) against
. Further insights on the activity of these compounds were gathered from molecular docking studies. The results suggest that these BODIPYs act as competitive inhibitors targeting the NADPH/NADP
linkage site of the pteridine reductase (PR) enzyme. Additionally, these findings unveil a range of quasi-degenerate binding complexes formed between the PRs and the investigated BODIPY derivatives. These results suggest a potential correlation between the anti-parasitic activity and the presence of multiple configurations that block the same site of the enzyme.
Unnatural amino acids with enhanced properties, such as increased complexing ability and luminescence, are considered to be highly attractive building blocks for bioinspired frameworks, such as ...probes for biomolecule dynamics, sensitive fluorescent chemosensors, and peptides for molecular imaging, among others. Therefore, a novel series of highly emissive heterocyclic alanines bearing a benzo
oxazolyl unit functionalized with different heterocyclic π-spacers and (aza)crown ether moieties was synthesized. The new compounds were completely characterized using the usual spectroscopic techniques and evaluated as fluorimetric chemosensors in acetonitrile and aqueous mixtures in the presence of various alkaline, alkaline-earth, and transition metal ions. The different crown ether binding moieties as well as the electronic nature of the π-bridge allowed for fine tuning of the sensory properties of these unnatural amino acids towards Pd
and Fe
, as seen by spectrofluorimetric titrations.
Four imidazoanthraquinone derivatives (2a–d) were synthesized and characterized and their coordination behavior against selected anions and cations tested. Acetonitrile solutions of probes showed ...charge-transfer absorptions in the 407–465 nm range. The four probes emitted in the 533–571 nm interval. The recognition ability of 2a–d was evaluated in the presence of F–, Cl–, Br–, I–, OCN–, BzO–, ClO4 –, AcO–, HSO4 –, H2PO4 –, and CN–. Only F–, AcO–, and H2PO4 – induced a new red-shifted absorption band that was attributed to a deprotonation process involving the amine moiety of the imidazole ring. Moreover, upon increasing quantities of F–, AcO–, and H2PO4 –, moderate quenching was induced in the emission of 2a–d together with the appearance of a new red-shifted band. The UV–visible and emission behavior of the four probes in the presence of Cu2+, Co2+, Mg2+, Fe3+, Ba2+, Fe2+, Ni2+, Ca2+, Zn2+, Pb2+, Cd2+, Cr3+, Al3+, K+, and Li+ was also assessed. Only addition of Fe3+, Cr3+, and Al3+ caused a new blue-shifted band in 2a–d that was ascribed to a preferential coordination with the acceptor part of the probes. Moreover, an important quenching of the emission was observed which was ascribed to the interaction between these trivalent cations and 2a–d.
(indolyl)methanes (BIMs) are a class of compounds that have been recognized as an important core in the design of drugs with important pharmacological properties, such as promising anticancer and ...antiparasitic activities. Here, we explored the biological activity of the BIM core functionalized with different (hetero)aromatic moieties. We synthesized substituted BIM derivatives with triphenylamine,
-dimethyl-1-naphthylamine and 8-hydroxylquinolyl groups, studied their photophysical properties and evaluated their in vitro antiproliferative and antiparasitic activities. The triphenylamine BIM derivative
displayed an IC
of 3.21, 3.30 and 3.93 μM against
,
and HT-29 cancer cell line, respectively. The selectivity index demonstrated that compound
was up to eight-fold more active against the parasites and HT-29 than against the healthy cell line MRC-5. Fluorescence microscopy studies with MRC-5 cells and
parasites incubated with derivative
indicate that the compound seems to accumulate in the cell's mitochondria and in the parasite's nucleus. In conclusion, the BIM scaffold functionalized with the triphenylamine moiety proved to be the most promising antiparasitic and anticancer agent of this series.
The development of sensors for pH monitoring is of extreme importance in the monitoring of concrete and reinforced concrete structures. Imidazole derivatives are promising probes for pH sensing due ...to the amphoteric nature of their heterocyclic ring, which can be protonated/deprotonated upon pH changes. In this work, a triarylimidazole was synthesised and used as a dopant in an organic-inorganic hybrid (OIH) sol-gel matrix to obtain a pH-sensitive membrane for further application in optical fibre sensors (OFS). The triarylimidazole probe shows fluorimetric response in pH between 9 and 13, which is the desired range for monitoring carbonation of concrete. This degradation process lowers the highly alkaline pH of concrete (12.5-13) to values below 9, which creates favourable conditions for corrosion of concrete reinforcement. The OIH membranes used were based on Jeffamine THF170 and 3-glycidoxypropytrimethoxysilane precursors, which had already been shown to be suitable and resistant in contact with cement-based materials. The OIHs were doped with three different contents of the triarylimidazole and the structural, dielectric, thermal and optical properties of the pure and doped OIH materials were evaluated. The structural analysis showed that the presence of the triarylimidazole did not change the structural properties of the OIH material. Electrochemical impedance spectroscopy showed that in the doped samples the conductivity increased with the imidazole concentration. The
r
obtained for the doped samples ranged approximately from 11 to 19 and for the pure matrices was 8. Thermal analysis showed that these materials are stable up to 350 °C and that the presence of the probe did not change that feature. The optical properties showed that the prepared OIH materials have promising properties to be used as pH sensitive fluorimetric probes.
OIH sol-gel materials based on Jeffamine THF-170 and GPTMS, doped with triarylimidazole, were synthesized. The
r
obtained for the OIH doped samples ranged between 11 and 19. The OIHs are thermally stable for fresh concrete purposes.
Electrospinning and wet-spinning have been recognized as two of the most efficient and promising techniques for producing polymeric fibrous constructs for a wide range of applications, including ...optics, electronics, food industry and biomedical applications. They have gained considerable attention in the past few decades because of their unique features and tunable architectures that can mimic desirable biological features, responding more effectively to local demands. In this review, various fiber architectures and configurations, varying from monolayer and core-shell fibers to tri-axial, porous, multilayer, side-by-side and helical fibers, are discussed, highlighting the influence of processing parameters in the final constructs. Additionally, the envisaged biomedical purposes for the examined fiber architectures, mainly focused on drug delivery and tissue engineering applications, are explored at great length.
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