Recent advances of Pluronic-based copolymers functionalization in biomedical applications.

The design of polymeric biocompatible nanomaterials for biological and medical applications has received special attention in recent years. Among different polymers, the triblock type copolymers (EO)(PO)(EO) or Pluronics® stand out due its favorable characteristics such as biocompatibility, low tissue adhesion, thermosensitivity, and structural capacity to produce different types of macro and nanostructures, e.g.

Nanocomposite Films of Silver Nanoparticles and Conjugated Copolymer in Natural and Nano-Form: Structural and Morphological Studies.

The use of conjugated polymers (CPs) and metallic nanoparticles is an interesting way to form nanocomposites with improved optical properties. For instance, a nanocomposite with high sensitivity can be produced. However, the hydrophobicity of CPs may hamper applications due to their low bioavailability and low operability in aqueous media.

Influence of Ag size and shape in dye photodegradation using silver nanoparticle/ZnO nanohybrids and polychromatic light.

In this work, we propose zinc oxide (ZnO) surface functionalization with plasmonic silver nanoparticles (AgNP) of different sizes and shapes (spheres, prisms, and rods) creating ZnO/AgNP nanohybrids. These were characterized by UV-Vis spectroscopy, X-ray diffraction, transmission electron microscopy, Fourier-transform infrared spectroscopy, diffuse reflectance spectroscopy, and photoluminescence spectroscopy. Surface functionalization with AgNP improved photocatalyst electronic properties, its visible light absorption, and slow electron/hole recombination on the ZnO surface.

Pluronic-loaded Silver Nanoparticles/Photosensitizers Nanohybrids: Influence of the Polymer Chain Length on Metal-enhanced Photophysical Properties.

Silver nanoparticles (AgNPs) are incredibly versatile nanostructures that more recently have been exploited to create advanced optoelectronic materials due enhancement of local magnetic field after its irradiation. However, the use of AgNPs as nanoantennas to amplify photophysical properties of close photosensitizer (PS) molecules in photodynamic therapy is still underexplored. The reason for that is the difficulty to control crucial parameters such as silver-PS distance in aqueous solution.

Synthesis of Pluronic-based silver nanoparticles/methylene blue nanohybrids: Influence of the metal shape on photophysical properties.

Nanotechnology development provides new strategies to improve different treatment modalities by integration of multiple molecules in a single multifunctional nanoparticle. In this scenario, we highlight silver nanoparticles (AgNPs) favorable optical properties such as absorption and emission of light in the visible region of the spectrum. This allows its synergic combination with the photosensitizer molecule methylene blue (MB) in order to improve outcomes in photodynamic-based therapies.

"Biotin-targeted mixed liposomes: A smart strategy for selective release of a photosensitizer agent in cancer cells".

The high incidence of cancer, necessity of treatment, and prognosis times are urgent issues that need to be addressed. In this work, we present DPPC liposomes coated with F127 triblock copolymers as a promising alternative in drug delivery systems for cancer therapy. The proposed mixed liposomes exhibit adequate size, high stability, and passive targeting that result from the EPR effect.

Prodrugs for targeted cancer therapy.

: Prodrugs have been used to improve the selectivity and efficacy of cancer therapy by targeting unique abnormal markers that are overexpressed by cancer cells and are absent in normal tissues. In this context, different strategies have been exploited and new ones are being developed each year. : In this review, an integrated view of the potential use of prodrugs in targeted cancer therapy is provided.

PEG-coated vesicles from Pluronic/lipid mixtures for the carrying of photoactive erythrosine derivatives.

Liposomes are very attractive membrane models and excellent drug delivery systems. Concerning their drug delivery aspects, the mixing liposomes with biocompatible copolymers allows for stability and the incorporation of several drugs. We developed PEG coated vesicles from the mixture of DPPC and F127 Pluronic copolymer to obtain long-circulating nanoparticles (mixed vesicles).

Magneto low-density nanoemulsion (MLDE): A potential vehicle for combined hyperthermia and photodynamic therapy to treat cancer selectively.

In this paper, we introduce a new drug delivery system (DDS) called magneto low-density nanoemulsion (MLDE), which can carry maghemite nanoparticles and Chlorin e6 as an active photosensitizer drug. This design can enhance tumor damage after minor heat dissipation and/or minimum visible light photosensitization doses by classical magnetic hyperthermia (MHT) and photodynamic therapy (PDT), respectively. We establish protocols to prepare the MLDE and to load the drug combination onto it.

In vitro/in vivo investigation on the potential of Pluronic® mixed micelles for pulmonary drug delivery.

In this paper, we shed light on the potential of Pluronic® mixed micelles in lung delivery of poorly water-soluble drugs. To this purpose, Pluronic® P123/F127 mixed micelles (PMM), exhibiting superior stability in biological fluids, were loaded with budesonide (BUD), a model hydrophobic corticosteroid, and fully investigated focusing on their stability in pulmonary-relevant media, transport through the mucus barrier and aerodynamic behaviour in vitro. Then, lung bio-distribution and efficacy were evaluated in vivo, after intra-tracheal administration in rats.

Light source is critical to induce glioblastoma cell death by photodynamic therapy using chloro-aluminiumphtalocyanine albumin-based nanoparticles.

Selection of an efficient light source is fundamental in the development of photodynamic therapy (PDT) protocols. However, few studies provide a comparison of different light sources with regard to phototoxic effects. Here, we compared the cell death induced by photoactivation of chloro-aluminiumphtalocyanine (AlClPc)-loaded human serum albumin nanoparticles under irradiation with different light sources: continuous laser (CL), pulsed laser (PL), and light-emitting diode (LED).

Spotlight on the delivery of photosensitizers: different approaches for photodynamic-based therapies.

Nanomedicine development allowed the discovery of new photosensitizers (PS) and drug delivery systems (DDS) to overcome current issues on phototherapy. Nano-engineered materials have the potential to improve the solubility of PS, control drug pharmacokinetics, decreasing side effects, increasing bioavailability, and overcoming multidrug resistance. A recent approach is the co-delivery of PS with other therapeutic agents in a multimodal platform for synergic and improved results.

Multifunctional theranostic Pluronic mixed micelles improve targeted photoactivity of Verteporfin in cancer cells.

Nanotechnology development provides new strategies to treat cancer by integration of different treatment modalities in a single multifunctional nanoparticle. In this scenario, we applied the multifunctional Pluronic P123/F127 mixed micelles for Verteporfin-mediated photodynamic therapy in PC3 and MCF-7 cancer cells. Micelles functionalization aimed the targeted delivery by the insertion of biotin moiety on micelle surface and fluorescence image-based through rhodamine-B dye conjugation in the polymer chains.

Nanostructured Polymeric Micelles Carrying Xanthene Dyes for Photodynamic Evaluation.

It was evaluated the properties of the xanthene dyes Erythrosin B, Eosin Y and theirs Methyl, Butyl and Decyl ester derivatives as possible photosensitizers (PS) for photodynamic treatments. The more hydrophobic dyes self-aggregate in water/ethanol solutions above 70% water (vol/vol) in the mixture. In buffered water, these PS were encapsulated in Pluronic polymeric surfactants of P-123 and F-127 by two methodologies: direct addition and the thin-film solid dispersion methods.

Pluronic P123/F127 mixed micelles delivering sorafenib and its combination with verteporfin in cancer cells.

Here, we developed Pluronic P123/F127 (poloxamer) mixed micelles for the intravenous delivery of the anticancer drug sorafenib (SRB) or its combination with verteporfin (VP), a photosensitizer for photodynamic therapy that should complement well the cytotoxicity profile of the chemotherapeutic. SRB loading inside the core of micelles was governed by the drug:poloxamer weight ratio, while in the case of the SRB-VP combination, a mutual interference between the two drugs occurred and only specific ratios could ensure maximum loading efficiency. Coentrapment of SRB did not alter the photophysical properties of VP, confirming that SRB did not participate in any bimolecular process with the photosensitizer.

Singlet oxygen production by combining erythrosine and halogen light for photodynamic inactivation of Streptococcus mutans.

Background: Photodynamic inactivation of microorganisms is based on a photosensitizing substance which, in the presence of light and molecular oxygen, produces singlet oxygen, a toxic agent to microorganisms and tumor cells. This study aimed to evaluate singlet oxygen quantum yield of erythrosine solutions illuminated with a halogen light source in comparison to a LED array (control), and the photodynamic effect of erythrosine dye in association with the halogen light source on Streptococcus mutans.

Methods: Singlet oxygen quantum yield of erythrosine solutions was quantified using uric acid as a chemical-probe in an aqueous solution.

Biotin-targeted Pluronic(®) P123/F127 mixed micelles delivering niclosamide: A repositioning strategy to treat drug-resistant lung cancer cells.

With the aim to develop alternative therapeutic tools for the treatment of resistant cancers, here we propose targeted Pluronic(®) P123/F127 mixed micelles (PMM) delivering niclosamide (NCL) as a repositioning strategy to treat multidrug resistant non-small lung cancer cell lines. To build multifunctional PMM for targeting and imaging, Pluronic(®) F127 was conjugated with biotin, while Pluronic(®) P123 was fluorescently tagged with rhodamine B, in both cases at one of the two hydroxyl end groups. This design intended to avoid any interference of rhodamine B on biotin exposition on PMM surface, which is a key fundamental for cell trafficking studies.

Polymeric Nanoparticles for Cancer Photodynamic Therapy.

In chemotherapy a fine balance between therapeutic and toxic effects needs to be found for each patient, adapting standard combination protocols each time. Nanotherapeutics has been introduced into clinical practice for treating tumors with the aim of improving the therapeutic outcome of conventional therapies and of alleviating their toxicity and overcoming multidrug resistance. Photodynamic therapy (PDT) is a clinically approved, minimally invasive procedure emerging in cancer treatment.

Photodegradation in Micellar Aqueous Solutions of Erythrosin Esters Derivatives.

Strong light absorption and high levels of singlet oxygen production indicate erythrosin B as a viable candidate as a photosensitizer in photodynamic therapy or photodynamic inactivation of microorganisms. Under light irradiation, erythrosin B undergoes a photobleaching process that can decrease the production of singlet oxygen. In this paper, we use thermal lens spectroscopy to investigate photobleaching in micellar solutions of erythrosin ester derivatives: methyl, butyl, and decyl esters in low concentrations of non-ionic micellar aqueous solutions.

β-cyclodextrin nanosponges as multifunctional ingredient in water-containing semisolid formulations for skin delivery.

A β-cyclodextrin nanosponge cross-linked with pyromellitic dianhydride (βNS-PYRO) is reported for the first time as multifunctional ingredient in semisolid formulations for drug delivery to the skin. The role of βNS-PYRO on solubilization and stabilization of the photosensitizer benzoporphyrin-derivative monoacid ring A (BPDMA) and all-trans retinoic acid (atRA) as well as its effect on skin permeation of diclofenac (DIC) was investigated. Aqueous solutions, gels, and cream-gels were prepared from mixtures of βNS-PYRO with a conventional gelling agent at specific ratios.

pKa determinations of xanthene derivates in aqueous solutions by multivariate analysis applied to UV-Vis spectrophotometric data.

Xanthenes form to an important class of dyes which are widely used. Most of them present three acid-base groups: two phenolic sites and one carboxylic site. Therefore, the pKa determination and the attribution of each group to the corresponding pKa value is a very important feature.