Bimetallic Europium and Terbium Complexes Containing Substituted Terpyridines and the NSAID Drug Tolfenamic Acid: Structural Differences, Luminescence Properties, and Theranostic Applications

Coating of polydimethylsiloxane nanoparticles improves bioactivity of cellulose paper for culture of fibroblasts

Paper has recently emerged as a promising platform for cell culture owing to its flexible three-dimensional matrix, high porosity, biocompatibility, cost-effectiveness and widespread availability. However, native paper is devoid of cell adhesion motifs and various surface modification techniques are generally employed on paper substrate before cell seeding, most of which are complicated, expensive, time-consuming and require use of sophisticated instruments. In the present work, for the first time, we have coated polydimethylsiloxane (PDMS) nanoparticles (NPs) onto the cellulose fibers of paper to improve its bioactivity while retaining the fibrous morphology. A modified nanoprecipitation method was employed to prepare PDMS NPs of ~30 nm size and 1 mg/ml concentration. Owing to the inherent skin-like mechanical properties of PDMS, the NPs could offer anchoring sites to the skin cells in the form of nanotopographic and biomechanical cues for enhanced interaction with the paper matrix. NIH/3T3 fibroblast cells cultured on the coated paper substrate exhibited elongated and spindle like morphology (characteristic of fibroblasts in vivo) with an increase in cellular adhesion and proliferation (ca. 74 % more cell viability after 48 h as compared to uncoated paper). After culturing for 15 days, the fibroblasts secreted excessive collagen and formed tissue-like sheet of cells which further advocate for the excellent suitability of the PDMS NPs coated paper substrate for culture of skin cells.

Strategic enhancement of collagen detection using lanthanide-functionalized collagen targeted peptides

Monitoring collagen denaturation is crucial for diagnosing collagen-related diseases such as tumors and fibrosis. Herein, we have developed specific probes to detect denatured collagen (d-Col) and collagen I (Col I), utilizing peptide probes with sequences (GOP)10 and HVWMQAP, targeting at d-Col and Col I, respectively. These peptides were conjugated with 1,10-phenanthroline-5-carboxylic Acid (Phen), forming Phen-Ahx-(GOP)10 and Phen-Ahx-HVWMQAP. Phen acts as both an antenna sensitizer and a chelator, coordinating with Terbium (III) and Europium (III) ions via its nitrogen atom, facilitating fluorescent emission in green and red, respectively. The investigation demonstrated that Tb3+ interacts with three (GOP)10 peptide units through Phen, while Eu3+ connects with four units of Ahx-HVWMQAP peptides. Additionally, it is important to note that the structure of the peptides remains unchanged after chelating with the lanthanide ions, maintaining their integrity throughout the process. These probes have effectively demonstrated their ability to bind to specific collagen types with selectivity, enabling accurate identification of their presence. The excellent binding of these probes is due to the branched structure of the formed lanthanide-peptide complexes. A dose-dependent linear association was observed in the binding of Eu-[Phen-Ahx-HVWMQAP]4 to Col I, with concentration levels ranging from 0.5 to 100 μM and a minimal detectable concentration of 0.113 μM. We anticipate that our developed probes will improve understanding of collagen remodeling and provide opportunities for the diagnosis of collagen-associated diseases.

Fenamates: Forgotten treasure for cancer treatment and prevention: Mechanisms of action, structural modification, and bright future

Fenamates as classical nonsteroidal anti-inflammatory agents are widely used for relieving pain. Preclinical studies and epidemiological data highlight their chemo-preventive and chemotherapeutic potential for cancer. However, comprehensive reviews of fenamates in cancer are limited. To accelerate the repurposing of fenamates, this review summarizes the results of fenamates alone or in combination with existing chemotherapeutic agents. This paper also explores targets of fenamates in cancer therapy, including COX, AKR family, AR, gap junction, FTO, TEAD, DHODH, TAS2R14, ion channels, and DNA. Besides, this paper discusses other mechanisms, such as regulating Wnt/β-catenin, TGF-β, p38 MAPK, and NF-κB pathway, and the regulation of the expressions of Sp, EGR-1, NAG-1, ATF-3, ErbB2, AR, as well as the modulation of the tumor immune microenvironment. Furthermore, this paper outlined the structural modifications of fenamates, highlighting their potential as promising leads for anticancer drugs.

Synthesis, structure and biological activity of silver(I) complexes containing triphenylphosphine and non-steroidal anti-inflammatory drug ligands

Two Ag(I) complexes containing triphenylphosphine and non-steroidal anti-inflammatory drug ligands were synthesized and investigated using various spectroscopic studies and single crystal X-ray crystallography. The binding properties of tolfenamic acid, ibuprofen and the two complexes with DNA and BSA were investigated using UV or fluorescence spectroscopy. The results showed that two Ag(I) complexes bound to DNA by the intercalation mode and interacted with BSA using a static quenching procedure. Furthermore, the results of fluorescence titration suggested that the complexes had good affinity for BSA and one binding site close to BSA. The in vitro cytotoxicity of tolfenamic acid, ibuprofen, and the two complexes against four human carcinoma cell lines (MCF-7, HepG-2, A549, and HeLa cells) was tested using an MTT assay. Complex 1 had higher cytotoxicity against HeLa cells. The intracellular reactive oxygen species (ROS) assay showed complex 1 induced the ROS generation in HeLa cells in a concentration dependent manner. Flow cytometry analysis showed complex 1 could suppress the HeLa cells growth during the G0/G1 phase and induce apoptosis in dose-depended manner.

Luminescent Lanthanide Probes for Inorganic and Organic Phosphates

Inorganic and organic phosphates-including orthophosphate, nucleotides, and DNA-are some of the most fundamental anions in cellular biology, regulating numerous processes of both medical and environmental significance. The characteristic long lifetimes of emitting lanthanides, including the brighter europium(III) and terbium(III), make them ideally suited for the development of molecular probes for the detection of phosphates directly in complex aqueous media. Moreover, given their high oxophilicity and the exquisite sensitivity of their quantum yields to their hydration number, those luminescent lanthanides are perfect for the detection of phosphates. Herein we discuss the principles that have guided the recent developments of molecular probes selective for inorganic or organic phosphates and how these lanthanide complexes facilitate the study of numerous biological processes.

An emissive dual-sensitized bimetallic Eu2III-bioprobe: design strategy, biological interactions, and nucleolus staining studies

A dual sensitized Eu2III–bioprobe (1) offers incredible opportunities for fine-tuning and exploring a strongly luminescent probe as a nucleolus staining agent.

Luminescent lanthanide(III) complexes of DTPA-bis(amido-phenyl-terpyridine) for bioimaging and phototherapeutic applications

We report here a series of coordinatively-saturated and thermodynamically stable luminescent [Ln(dtntp)(H₂O)] [Ln(III) = Eu (1), Tb (2), Gd (3), Sm (4) and Dy (5)] complexes using an aminophenyl-terpyridine appended-DTPA (dtntp) chelating ligand as cell imaging and photocytotoxic agents. The N,N″-bisamide derivative of H₅DTPA named as dtntp is based on 4'-(4-aminophenyl)-2,2':6',2″-terpyridine conjugated to diethylenetriamine-N,N',N″-pentaacetic acid. The structure, physicochemical properties, detailed photophysical aspects, interaction with DNA and serum proteins, and photocytotoxicity were studied. The intrinsic luminescence of Eu(III) and Tb(III) complexes due to f → f transitions used to evaluate their cellular uptake and distribution in cancer cells. The solid-state structure of [Eu(dtntp)(DMF)] (1·DMF) shows a discrete mononuclear molecule with nine-coordinated {EuN₃O₆} distorted tricapped-trigonal prism (TTP) coordination geometry around the Eu(III). The {EuN₃O₆} core results from three nitrogen atoms and three carboxylate oxygen atoms, and two carbonyl oxygen atoms of the amide groups of dtntp ligand. The ninth coordination site is occupied by an oxygen atom of DMF as a solvent from crystallization. The designed probes have two aromatic pendant phenyl-terpyridine (Ph-tpy) moieties as photo-sensitizing antennae to impart the desirable optical properties for cellular imaging and photocytotoxicity. The photostability, coordinative saturation, and energetically rightly poised triplet states of dtntp ligand allow the efficient energy transfer (ET) from Ph-tpy to the emissive excited states of the Eu(III)/Tb(III), makes them luminescent cellular imaging probes. The Ln(III) complexes show significant binding tendency to DNA (K ~ 10⁴ M^-1), and serum proteins (BSA and HSA) (K ~ 10⁵ M^-1). The luminescent Eu(III) (1) and Tb(III) (2) complexes were utilized for cellular internalization and cytotoxicity studies due to their optimal photophysical properties. The cellular uptake studies using fluorescence imaging displayed intracellular (cytosolic and nuclear) localization in cancer cells. The complexes 1 and 2 displayed significant photocytotoxicity in HeLa cells. These results offer a modular design strategy with further scope to utilize appended N,N,N-donor tpy moiety for developing light-responsive luminescent Ln(III) bioprobes for theranostic applications.

Luminescent EuIIIand TbIIIbimetallic complexes of N,N′-heterocyclic bases and tolfenamic acid: structures, photophysical aspects and biological activity

The isostructural bimetallic luminescent Eu^IIIand Tb^IIIdimers containing N,N′-heterocyclic bases and tolfenamic acid as a bridging ligands were evaluated for their structures, cellular imaging capability and photocytotoxicity.