COSAN-stabilised omega-3 oil-in-water nanoemulsions to prolong lung residence time for poorly water soluble drugs

Design and fabrication of a microfluidic system with embedded circular channels for rotary cell culture

The development of functional blood vessels is today a fundamental pillar in the evaluation of new therapies and diagnostic agents. This article describes the manufacture and subsequent functionalization, by means of cell culture, of a microfluidic device with a circular section. Its purpose is to simulate a blood vessel in order to test new treatments for pulmonary arterial hypertension. The manufacture was carried out using a process in which a wire with a circular section determines the dimensions of the channel. To fabricate the blood vessel, cells were seeded under rotary cell culture to obtain a homogeneous cell seeding in the inner wall of the devices. This is a simple and reproducible method that allows the generation of blood vessel models in vitro.

Water soluble organometallic small molecules as promising antibacterial agents: synthesis, physical-chemical properties and biological evaluation to tackle bacterial infections

The Na[3,3'-Fe(8-I-1,2-C₂B₉H₁₀)₂] and Na[2,2'-M(1,7-C₂B₉H₁₁)] (M = Co³⁺, Fe³⁺) small molecules are synthesized and the X-ray structures of [(H₃O)(H₂O)₅][2,2'-Co(1,7-C₂B₉H₁₁)₂] and [Cs(MeCN)][8,8'-I₂-Fe(1,2 C₂B₉H₁₀)₂], both displaying a transoid conformation of the [M(C₂B₉)₂]^- framework, are reported. Importantly, the supramolecular structure of [(H₃O)(H₂O)₅][2,2'-Co(1,7-C₂B₉H₁₁)₂] presents 2D layers leading to a lamellar arrangement of the anions while the cation layers form polymeric water rings made of six- and four-membered rings of water molecules connected via OH⋯H hydrogen bonds; B-H⋯O contacts connect the cationic and anionic layers. Herein, we highlight the influence of the ligand isomers (ortho-/meta-), the metal effect (Co³⁺/Fe³⁺) on the same isomer, as well as the influence of the presence of the iodine atoms on the physical-chemical and biological properties of these molecules as antimicrobial agents to tackle antibiotic-resistant bacteria, which were tested with four Gram-positive bacteria, five Gram-negative bacteria, and three Candida albicans strains that have been responsible for human infections. We have demonstrated an antimicrobial effect against Candida species (MIC of 2 and 3 nM for Na[3,3'-Co(8-I-1,2-C₂B₉H₁₀)₂] and Na[2,2'-Co(1,7-C₂B₉H₁₁)₂], respectively), and against Gram-positive and Gram-negative bacteria, including multiresistant MRSA strains (MIC of 6 nM for Na[3,3'-Co(8-I-1,2-C₂B₉H₁₀)₂]). The selectivity index for antimicrobial activity of Na[3,3'-Co(1,2-C₂B₉H₁₁)₂] and Na[3,3'-Co(8-I-1,2-C₂B₉H₁₀)₂] compounds is very high (165 and 1180, respectively), which reveals that these small anionic metallacarborane molecules may be useful to tackle antibiotic-resistant bacteria. Moreover, we have demonstrated that the outer membrane of Gram-negative bacteria constitutes an impermeable barrier for the majority of these compounds. Nonetheless, the addition of two iodine groups in the structure of the parent Na[3,3'-Co(1,2-C₂B₉H₁₁)₂] had an improved effect (3-7 times) against Gram-negative bacteria. Possibly the changes in their physical-chemical properties make the meta-isomers and the ortho-di-iodinated small molecules more permeable for crossing this barrier. It should be emphasized that the most active metallabis(dicarbollide) small molecules are both transoid conformers in contrast to the ortho- [3,3'-Co(1,2-C₂B₉H₁₁)₂]^- that is cisoid. The fact that these small molecules cross the mammalian membrane and have antimicrobial properties but low toxicity for mammalian cells (high selectivity index, SI) represents a promising tool to treat infectious intracellular bacteria. Since there is an urgent need for antibiotic discovery and development, this study represents a relevant advance in the field.

Cobaltabis(dicarbollide) ([o-COSAN]-) as Multifunctional Chemotherapeutics: A Prospective Application in Boron Neutron Capture Therapy (BNCT) for Glioblastoma

PURPOSE

The aim of our study was to assess if the sodium salt of cobaltabis(dicarbollide) and its di-iodinated derivative (Na[o-COSAN] and Na[8,8'-I2-o-COSAN]) could be promising agents for dual anti-cancer treatment (chemotherapy + BNCT) for GBM.

METHODS

The biological activities of the small molecules were evaluated in vitro with glioblastoma cells lines U87 and T98G in 2D and 3D cell models and in vivo in the small model animal Caenorhabditis elegans (C. elegans) at the L4-stage and using the eggs.

RESULTS

Our studies indicated that only spheroids from the U87 cell line have impaired growth after treatment with both compounds, suggesting an increased resistance from T98G spheroids, contrary to what was observed in the monolayer culture, which highlights the need to employ 3D models for future GBM studies. In vitro tests in U87 and T98G cells conclude that the amount of 10B inside the cells is enough for BNCT irradiation. BNCT becomes more effective on T98G after their incubation with Na[8,8'-I2-o-COSAN], whereas no apparent cell-killing effect was observed for untreated cells.

CONCLUSIONS

These small molecules, particularly [8,8'-I2-o-COSAN]-, are serious candidates for BNCT now that the facilities of accelerator-based neutron sources are more accessible, providing an alternative treatment for resistant glioblastoma.

Biodistribution of 68/67Ga-Radiolabeled Sphingolipid Nanoemulsions by PET and SPECT Imaging

Background and Purpose

Non-invasive imaging methodologies, especially nuclear imaging techniques, have undergone an extraordinary development over the last years. Interest in the development of innovative tracers has prompted the emergence of new nanomaterials with a focus on nuclear imaging and therapeutical applications. Among others, organic nanoparticles are of the highest interest due to their translational potential related to their biocompatibility and biodegradability. Our group has developed a promising new type of biocompatible nanomaterials, sphingomyelin nanoemulsions (SNs). The aim of this study is to explore the potential of SNs for nuclear imaging applications.

Methods

Ready-to-label SNs were prepared by a one-step method using lipid derivative chelators and characterized in terms of their physicochemical properties. Stability was assessed under storage and after incubation with human serum. Chelator-functionalized SNs were radiolabeled with ⁶⁷Ga and ⁶⁸Ga, and the radiochemical yield (RCY), radiochemical purity (RCP) and radiochemical stability (RCS) were determined. Finally, the biodistribution of ^67/68Ga-SNs was evaluated in vivo and ex vivo.

Results

Here, we describe a simple and mild one-step method for fast and efficient radiolabeling of SNs with ⁶⁸Ga and ⁶⁷Ga radioisotopes. In vivo experiments showed that ^67/68Ga-SNs can efficiently and indistinctly be followed up by PET and SPECT. Additionally, we proved that the biodistribution of the ^67/68Ga-SNs can be conveniently modulated by modifying the surface properties of different hydrophilic polymers, and therefore the formulation can be further adapted to the specific requirements of different biomedical applications.

Conclusion

This work supports ^67/68Ga-SNs as a novel probe for nuclear imaging with tunable biodistribution and with great potential for the future development of nanotheranostics.

Preparing (Metalla)carboranes for Nanomedicine

"There's plenty of room at the bottom" (Richard Feynman, 1959): an invitation for (metalla)carboranes to enter the (new) field of nanomedicine. For two decades, the number of publications on boron cluster compounds designed for potential applications in medicine has been constantly increasing. Hundreds of compounds have been screened in vitro or in vivo for a variety of biological activities (chemotherapeutics, radiotherapeutics, antiviral, etc.), and some have shown rather promising potential for further development. However, until now, no boron cluster compounds have made it to the clinic, and even clinical trials have been very sparse. This review introduces a new perspective in the field of medicinal boron chemistry, namely that boron-based drugs should be regarded as nanomedicine platforms, due to their peculiar self-assembly behaviour in aqueous solutions, and treated as such. Examples for boron-based 12- and 11-vertex clusters and appropriate comparative studies from medicinal (in)organic chemistry and nanomedicine, highlighting similarities, differences and gaps in physicochemical and biological characterisation methods, are provided to encourage medicinal boron chemists to fill in the gaps between chemistry laboratory and real applications in living systems by employing bioanalytical and biophysical methods for characterising and controlling the aggregation behaviour of the clusters in solution.

Interfacial activity of modified dextran polysaccharide to produce enzyme-responsive oil-in-water nanoemulsions

Herein, we report the evaluation of dextran (DXT) derivatives bearing hydrophobic or hydrophilic functional groups as stabilisers of oil-in-water (O/W) emulsions. All investigated modifications conferred interfacial activity to produce stable O/W emulsions, methacrylate(MA)-functionalised DXT being the most promising stabiliser. A minimum amount of MA was required to obtain stable O/W nanoemulsions, which could be degraded in the presence of lipases.