Nanoarchitectonics of Multifunctional Niosomes for Advanced Drug Delivery.

Niosomes are a type of vesicular nanocarrier exploited for enhancing the therapeutic efficacy of various drugs in clinical practice. Niosomes comprise a bilayer hydrophobic membrane enclosing a central cavity filled with an aqueous phase, and therefore, they can encapsulate and deliver both hydrophobic and hydrophilic substances. Niosomal nanocarriers are preferred over other bilayer structures such as liposomes due to their chemical stability, biodegradability, biocompatibility, low production cost, low toxicity, and easy storage and handling. In addition, the niosomal membrane can be easy modified by the inclusion of ligands or stimulus-sensitive segments for achieving targeted delivery and triggered release of the encapsulated cargo. This mini-review outlines the current advances in designing functional niosomes and their use as platforms for developing advanced drug and gene delivery systems.

Self-Assembly of a Thermally Responsive Double-Hydrophilic Copolymer in Ethanol-Water Mixtures: The Effect of Preferential Adsorption and Co-Nonsolvency.

Lower alcohols can induce a combined collapse-swelling de-mixing transition (lower critical solution temperature (LCST)-type co-nonsolvency) in aqueous solutions of poly( N-isopropylacrylamide) (PNIPAM) by interacting with the polymer's amide groups. This interaction results in an increase of the total surface area of hydrophobic sites and destabilizes the chains. Here, we make use of this phenomenon to drive the counterintuitive self-assembly of a PNIPAM-containing double-hydrophilic graft copolymer in water-ethanol mixtures at T ≪ LCST. Rheological frequency sweeps are used to quantify the distinct solvation states of PNIPAM at various temperatures and ethanol concentrations. The energy stored through elastic deformation at the de-mixing transition is simply related to the solvent binding. We find that the storage modulus decreases progressively, but nonlinearly with ethanol concentration, which evidences a preferential solvation pattern. Analogously, through a combination of dynamic light scattering and transmission electron microscope analyses, we demonstrate that a low-temperature structure variation takes place by adding ethanol following a similar solvent-content morphology dependent model.

Antioxidant and antiradical properties of esculin, and its effect in a model of epirubicin-induced bone marrow toxicity.

AIM: To evaluate the effect of esculin, a plant coumarin glucoside, on free radicals and against epirubicin-induced toxicity on bone marrow cells. MATERIALS AND METHODS: Antioxidant activity was assessed by a luminol-dependent chemiluminescence method or NBT test in a xanthine-xanthine oxidase system, and two iron-dependent lipid peroxidation systems. In vivo experiments were carried out in epirubicin-treated mice, alone or in a combination with esculin. Genotoxicity of the anthracycline drug was assessed by cytogenetic analysis and an autoradiographic assay. RESULTS: Esculin inactivated superoxide anion radicals in both systems we used. It exerted SOD-mimetic effect and reduced the level of superoxide radicals generated in a xanthine-xanthine oxidase system by 30%. Esculin also showed an antioxidant effect in a model of Fe2+-induced lipid peroxidation. Cytogenetic analysis showed that epirubicin had a marked influence on the structure of metaphase chromosomes of normal bone marrow cells. Inclusion of esculin in the treatment protocol failed to ameliorate the epirubicin-induced antiproliferative effects and genotoxicity in bone marrow cells. CONCLUSION: In this study the ability of the coumarin glucoside esculin to scavenge superoxide radicals and to decrease Fe-induced lipid peroxidation was documented. However, despite the registered antioxidant effects the tested compound failed to exert cytoprotection in models of anthracycline-induced genotoxicity in bone marrow cells. The results of this study warrant for more precise further evaluation of esculin, employing different test systems and end-points and a wider range of doses to more precisely appraise its potential role as a chemoprotective/resque agent.