Nanoencapsulation of quercetin via miniemulsion polymerization

Evaluation of the in vivo acute toxicity of poly(thioether-ester) and superparamagnetic poly(thioether-ester) nanoparticles obtained by thiol-ene miniemulsion polymerization

Poly(thioether-ester) (PTEe) nanoparticles obtained by thiol-ene polymerization have received attention of many researchers due to several advantages, including, biocompatibility and biodegradability. The search for new nanomaterials requires toxicity studies to assess potential toxic effects of their administration. Therefore, the aim of this study was to evaluate the in vivo acute toxicity of PTEe and poly(thioether-ester)-coated magnetic nanoparticles prepared by thiol-ene polymerization in miniemulsion. These nanoparticles presented a mean size of approximately 120 nm, spherical morphology, and negative surface charge. Doses of 40 mg/kg were administered intraperitoneally to Swiss mice and nociceptive, behavioral and biochemical parameters were investigated in five different organs. None of the nanoparticles led to any alterations in the nociceptive and behavioral responses. Biochemical alterations were observed in liver, decreasing the sulfhydryl and glutathione (GSH) levels, suggesting the dependence of the GSH metabolism in the elimination of the nanoparticles. In general, both nanoparticle types did not cause disturbances in biochemical parameters analyzed in others organs. These results suggest that both nanoparticle types did not induce acute toxicity to the different organs evaluated, reinforcing the biocompatibility of PTEe nanoparticles synthetized by thiol-ene polymerization.

Nanoconfinement-mediated cancer theranostics

Despite various therapeutic or diagnostic developments, cancer is still one of the most lethal diseases due to insufficiently adequate treatments and the delay of the early stage of disease detection. An image-guided drug delivery system (IGDDS), as a real-time noninvasive imaging assessment of therapeutic response, has the strong potential to improve the diagnosis and treatment of cancer because its imaging property offers the quantification of nanomedicine at the intended disease sites, the possible assurance of adequate treatment and elimination of undesirable delay of early-stage diagnosis due to low resolution. One of potential modality that overcomes these challenges could be the nanoconfinement of gold (Au) nanoparticles within other nanoparticles called "Particle-in-Particle (PIP)", which is a strong candidate of cancer treatment because of its "theranostic (therapy + diagnostics)" advantages including imaging (e.g., CT) and therapeutic hyperthermia application. In this review, we will elaborate on the current application of theranostic by nanoconfinement. Then, we will narrow down the gold nanoparticle-mediated theranostic application and its nanoconfinement advantages. Finally, the future direction for maximum nanoconfinement mediated cancer therapy will be included.

Method Validation for Progesterone Determination in Poly(methyl methacrylate) Nanoparticles Synthesized via Miniemulsion Polymerization

Exogenous progesterone has several applications in human health and in veterinary medicine, especially in fixed-time artificial insemination protocol. Progesterone nanoencapsulation in biocompatible polymers, such as poly(methyl methacrylate) (PMMA), is an alternative to substitute silicone-based release device traditionally used for estrus control. Progesterone concentration inside the nanoparticles must be precisely known; for that reason, a validation methodology must be applied to ensure reliable results, suitable for nanoparticles application. In this work, an UV-Vis spectrophotometric method was validated for the determination of progesterone in PMMA nanoparticles synthesized by miniemulsion polymerization. Chloroform was used as solvent, showing selectivity to the encapsulated drug and the components of the polymeric matrix did not influence progesterone recovery. Detection and quantitation limits (DL and QL) obtained were 0.32 and 0.96 mg·L−1, respectively, and precision tests (between different analysts and equipment) indicated acceptable Relative Standard Deviations (RSD < 5%). Miniemulsion polymerization reactions were carried out producing two different morphologies: nanospheres (NS) and nanocapsules (NC), with average intensity diameters (Dz) of 150–200 nm and 240–300 nm, respectively. Polymerization gravimetric conversions obtained for both cases were higher than 95% and encapsulation efficiencies greater than 69% and 90% for the nanospheres and nanocapsules, respectively.

Gold nanoparticle-enhanced luminescence of silicon quantum dots co-encapsulated in polymer nanoparticles

The preparation of two-component polymer composite nanoparticles encapsulating both Si quantum dots (SiQDs) and Au nanoparticles (AuNPs) by a single step miniemulsion polymerization of divinylbenzene is described. This simple and robust method affords well-defined polymer composite nanoparticles with mean diameters in a range of 100-200 nm and with narrow polydispersity indices as determined by dynamic light scattering and transmission electron microscopy. The successful encapsulation of AuNPs within poly(divinylbenzene) was confirmed by UV-visible spectroscopy and from TEM images. Plasmon-enhanced fluorescence of the luminescence of the SiQDs by AuNPs encapsulated within the polymer composite nanoparticles was evaluated by confocal microspectroscopy, and luminescence enhancements of up to 15 times were observed. These observations indicate that the luminescence of the SiQDs is enhanced by the proximity of the AuNPs. The polymer composite nanoparticles were successfully ink-jet printed onto a glass substrate, which demonstrates that these composites are processable in printing applications.

Preparação de nanopartículas poliméricas a partir da polimerização de monômeros: parte I

Nanopartículas poliméricas produzidas a partir de polímeros sintéticos, como copolímeros do ácido metacrílico, ésteres acrílicos ou metacrílicos, têm sido amplamente utilizadas na área farmacêutica para encapsulação de princípios ativos. Essas nanopartículas apresentam as vantagens de proteção, liberação controlada, melhor biodisponibilidade e menor toxicidade, proporcionando maior conforto aos pacientes e adesão ao tratamento. A produção das nanopartículas (nanocápsulas e nanosferas) por polimerização de monômeros é revisada e descrita neste artigo, evidenciando os parâmetros tecnológicos que interferem nas características físico-químicas das nanopartículas, como a solubilidade do princípio ativo, o volume e pH do meio de polimerização, a massa molar e concentração do monômero e a natureza e concentração do tensoativo.

Preparação de nanopartículas poliméricas a partir de polímeros pré-formados: parte II

Nanopartículas poliméricas produzidas a partir de polímeros pré-formados, como os poliésteres alifáticos, têm sido amplamente utilizadas para incorporar, principalmente, princípios ativos lipofílicos. A produção das nanopartículas (nanocápsulas e nanosferas) por polímeros pré-formados pode ser realizada por emulsificação-evaporação do solvente, por deslocamento do solvente, por salting-out ou por emulsificação-difusão do solvente. Estes métodos de produção estão revisados e descritos neste artigo, evidenciando os parâmetros tecnológicos que interferem nas características físico-químicas das nanopartículas, como a solubilidade do princípio ativo, o volume e pH do meio de polimerização, a massa molar e concentração do monômero e a natureza e concentração do tensoativo.

Encapsulation of natural phenolic compounds: A review. Pharmaceutics. 2011;3:793-829. [PMID: 24309309 PMCID: PMC3857059 DOI: 10.3390/pharmaceutics3040793]

Natural polyphenols are valuable compounds possessing scavenging properties towards radical oxygen species, and complexing properties towards proteins. These abilities make polyphenols interesting for the treatment of various diseases like inflammation or cancer, but also for anti-ageing purposes in cosmetic formulations, or for nutraceutical applications. Unfortunately, these properties are also responsible for a lack in long-term stability, making these natural compounds very sensitive to light and heat. Moreover, polyphenols often present a poor biodisponibility mainly due to low water solubility. Lastly, many of these molecules possess a very astringent and bitter taste, which limits their use in food or in oral medications. To circumvent these drawbacks, delivery systems have been developed, and among them, encapsulation would appear to be a promising approach. Many encapsulation methods are described in the literature, among which some have been successfully applied to plant polyphenols. In this review, after a general presentation of the large chemical family of plant polyphenols and of their main chemical and biological properties, encapsulation processes applied to polyphenols are classified into physical, physico-chemical, chemical methods, and other connected stabilization methods. After a brief description of each encapsulation process, their applications to polyphenol encapsulation for pharmaceutical, food or cosmetological purposes are presented.

Surfactant-free miniemulsion polymerization as a simple synthetic route to a successful encapsulation of magnetite nanoparticles

Due to the existing interest in new hybrid particles in the colloidal range based on both magnetic and polymeric materials for applications in biotechnological fields, this work is focused on the preparation of magnetic polymer nanoparticles (MPNPs) by a single-step miniemulsion process developed to achieve better control of the morphology of the magnetic nanocomposite particles. MPNPs are prepared by surfactant-free miniemulsion polymerization using styrene (St) as a monomer, hexadecane (HD) as a hydrophobe, and potassium persulfate (KPS) as an initiator in the presence of oleic acid (OA)-modified magnetite nanoparticles. The effect of the type of cross-linker used [divinylbenzene (DVB) and bis[2-(methacryloyloxy)ethyl] phosphate (BMEP)] together with the effect of the amount of an aid stabilizer (dextran) on size, particle size distribution (PSD), and morphology of the hybrid nanoparticles synthesized is analyzed in detail. The mixture of different surface modifiers produces hybrid nanocolloids with various morphologies: from a typical core-shell composed by a magnetite core surrounded by a polymer shell to a homogeneously distributed morphology where the magnetite is uniformly distributed throughout the entire nanocomposite.