Development of Berberine-Loaded Nanoparticles for Astrocytoma Cells Administration and Photodynamic Therapy Stimulation

Berberine (BBR) is known for its antitumor activity and photosensitizer properties in anti-cancer photodynamic therapy (PDT), and it has previously been favorably assayed against glioblastoma multiforme (GBM)-derived cells. In this work, two BBR hydrophobic salts, dodecyl sulfate (S) and laurate (L), have been encapsulated in PLGA-based nanoparticles (NPs), chitosan-coated by the addition of chitosan oleate in the preparation. NPs were also further functionalized with folic acid. All the BBR-loaded NPs were efficiently internalized into T98G GBM established cells, and internalization increased in the presence of folic acid. However, the highest mitochondrial co-localization percentages were obtained with BBR-S NPs without folic acid content. In the T98G cells, BBR-S NPs appeared to be the most efficient in inducing cytotoxicity events and were therefore selected to assess the effect of photodynamic stimulation (PDT). As a result, PDT potentiated the viability reduction for the BBR-S NPs at all the studied concentrations, and a roughly 50% reduction of viability was obtained. No significant cytotoxic effect on normal rat primary astrocytes was observed. In GBM cells, a significant increase in early and late apoptotic events was scored by BBR NPs, with a further increase following the PDT scheme. Furthermore, a significantly increased depolarization of mitochondria was highlighted following BBR-S NPs’ internalization and mostly after PDT stimulation, compared to untreated and PDT-only treated cells. In conclusion, these results highlighted the efficacy of the BBR-NPs-based strategy coupled with photoactivation approaches to induce favorable cytotoxic effects in GBM cells.

Recent Trends in the Design, Synthesis, Spectroscopic Behavior, and Applications of Benzazole-Based Molecules with Solid-State Luminescence Enhancement Properties

Molecules that exhibit solid-state luminescence enhancement, i.e. the rare property to be more strongly emissive in the solid state than in solution, find an increasing number of applications in the fields of optoelectronic and nanophotonic devices, sensors, security papers, imaging, and theranostics. Benzazole (BZ) heterocycles are of particular value in this context. The simple enlargement of their π-electron system using a -C=C-Ar or -N=C-Ar moiety is enough for intrinsic solid-state luminescence enhancement (SLE) properties to appear. Their association with a variety of polyaromatic motifs leads to SLE-active molecules that frequently display attractive electroluminescent properties and are sensitive to mechanical stimuli. The excited-state intramolecular proton transfer (ESIPT) process that takes place in some hydroxy derivatives reinforces the SLE effect and enables the development of new sensors based on a protection/deprotection strategy. BZ may also be incorporated into frameworks that are prototypical aggregation-induced enhancement (AIE) luminogens, such as the popular tetraphenylethene (TPE), leading to materials with excellent optical and electroluminescent performance. This review encompasses the various ways to use BZ units in SLE systems. It underlines the significant progresses recently made in the understanding of the photophysical mechanisms involved. A brief overview of the synthesis shows that BZ units are robust building blocks, easily incorporated into a variety of structures. Generally speaking, we try to show how these small heterocycles may offer advantages for the design of increasingly efficient luminescent materials.

Stimuli Responsive Confinement of a Molecular Rotor Based BODIPY Dye inside a Cucurbit[7]uril Nanocavity

Present study reports the interaction of a molecular rotor based BODIPY dye, 8-anilino-BODIPY (ABP), with a versatile macrocyclic molecule, cucurbit[7]uril (CB7), investigated through various techniques such as ground-state absorption, steady-state fluorescence, time-resolve emission, proton NMR, and quantum chemical studies. Although BODIPY dyes have widespread applications due to their intriguing photochemical properties, studies on their noncovalent interactions with different macrocyclic hosts, especially regarding their supramolecularly induced modulations in photophysical properties are very limited. The investigated BODIPY dye, especially its protonated ABPH⁺ form (pH ∼ 1), shows a large fluorescence enhancement on its interaction with the CB7 host, due to large reduction in the structural flexibility for the bound dye, causing a suppression in its nonradiative de-excitation process in the excited state. Unlike ABPH⁺, the neutral ABP form (pH ∼ 7) shows considerably weaker interaction with CB7. For ABPH⁺-CB7 system, observed photophysical results indicate formation of both 1:1 and 1:2 dye-to-host complexes. Plausible geometries of these complexes are obtained from quantum chemical studies which are substantiated nicely from ¹H NMR results. The response of the ABPH⁺-CB7 system toward changing temperature of the solution have also been investigated elaborately to understand the potential of the system in different stimuli-responsive sensor applications.

Berberine: A Promising Natural Isoquinoline Alkaloid for the Development of Hypolipidemic Drugs

Berberine, as a representative isoquinoline alkaloid, exhibits significant hypolipidemic activity in both animal models and clinical trials. Recently, a large number of studies on the lipid-lowering mechanism of berberine and studies for improving its hypolipidemic activity have been reported, but for the most part, they have been either incomplete or not comprehensive. In addition, there have been a few specific reviews on the lipid-reducing effect of berberine. In this paper, the physicochemical properties, the lipid-lowering mechanism, and studies of the modification of berberine all are discussed to promote the development of berberine as a lipid-lowering agent. Subsequently, this paper provides some insights into the deficiencies of berberine in the study of lipid-lowering drug, and based on the situation, some proposals are put forward.

Crystallographic and Energetic Insights into Reduced Dissolution and Physical Stability of a Drug-Surfactant Salt: The Case of Norfloxacin Lauryl Sulfate

A commonly used pharmaceutical surfactant, sodium lauryl sulfate (SLS), has been reported to reduce the dissolution rate of drugs due to the formation of a less soluble drug-lauryl sulfate salt. In this study, we provide direct crystallographic evidence of the formation of salt between SLS and norfloxacin (NOR), [NORH⁺][LS^-]·1.5 H₂O. The available crystal structure also enables the use of the energy framework to gain an understanding of the structure-property relationship. Results show that the hydrophobic methyl groups in SLS dominate the surfaces of the [NORH⁺][LS^-]·1.5 H₂O crystals, resulting in the increased hydrophobicity and reduced wettability by aqueous media. Moreover, an analysis of molecular environments and energy calculations of water molecules provides insight into the stability of [NORH⁺][LS^-]·1.5 H₂O with variations in the relative humidity and temperature. In summary, important pharmaceutical properties, such as solubility, dissolution, and thermal stability, of the drug-surfactant salt [NORH⁺][LS^-]·1.5 H₂O have been characterized and understood based on crystallographic and energetic analyses of the crystal structure.

Ionic aggregation-induced emission dye with bulky counterions for preparation of bright near-infrared polymeric nanoparticles

Dyes exhibiting aggregation-induced emission (AIE) are attractive building blocks for the preparation of bright fluorescent nanomaterials. AIEgens are especially efficient in pure dye aggregates, whereas they are much less explored as dopants in NPs built of hydrophobic polymers. Here, we describe an approach that combines cationic AIEgens with bulky hydrophobic counterions (fluorinated tetraphenylborates) that enables preparation of small and bright AIEgen-loaded polymeric NPs. To this end, we synthesised a cationic tetraphenylethylene (TPE) derivative and studied its salts with counterions of different sizes and hydrophobicities. In organic solvent/water mixtures, all these salts exhibited typical AIE behaviour, whereas only salts with bulky hydrophobic counterions exhibited strongly red-shifted emission in the near-infrared (NIR) region. Encapsulation of these salts into poly(methyl methacrylate-co-methacrylic acid) (PMMA-MA) NPs revealed that bulky counterions ensure (i) formation of small (∼50 nm) AIEgen-loaded polymeric NPs; (ii) good fluorescence quantum yield (up to 30%); and (iii) NIR emission reaching 700 nm. By contrast, AIEgens with small inorganic anions (perchlorate and hexafluorophosphate) blended with PMMA-MA produced large aggregates with emission in the far-red region. Single-particle microscopy revealed that our 50 nm AIEgen-loaded PMMA-MA NPs were 6-fold brighter than the NIR emitting quantum dots (QD705). These NPs feature low cytotoxicity and compatibility with live cell imaging, in contrast to large aggregates of AIEgens with small inorganic counterions that failed to internalize into the cells. The present work shows that combination of cationic AIEgens with bulky counterions opens new routes for the preparation of bright polymer-based nanomaterials.

2-Phenylbenzoxazole derivatives: a family of robust emitters of solid-state fluorescence

In addition to thermal, chemical and photochemical stability, the 2-phenylbenzoxazole fragment exhibits attractive emission properties in the solid state, thus leading to highly photoluminescent materials and sensors.