Surfactant Effect on the Physicochemical Characteristics of Solid Lipid Nanoparticles Based on Pillar[5]arenes

Novel monosubstituted pillar[5]arenes containing both amide and carboxyl functional groups were synthesized. Solid lipid nanoparticles based on the synthesized macrocycles were obtained. Formation of spherical particles with an average hydrodynamic diameter of 250 nm was shown for pillar[5]arenes containing N-(amidoalkyl)amide fragments regardless of their concentration. It was established that pillar[5]arene containing N-alkylamide fragments can form spherical particles with two different sizes (88 and 223 nm) depending on its concentration. Mixed solid lipid nanoparticles based on monosubstituted pillar[5]arenes and surfactant (dodecyltrimethylammonium chloride) were obtained for the first time. The surfactant made it possible to level the effect of the macrocycle concentration. It was found that various types of aggregates are formed depending on the macrocycle/surfactant ratio. Changing the macrocycle/surfactant ratio allows to control the charge of the particles surface. This controlled property will lead to the creation of molecular-scale porous materials that selectively interact with various types of substrates, including biopolymers.

Food nanoparticles from rice vinegar: isolation, characterization, and antioxidant activities

Abundant nanostructures have been constantly found in various foods, like vinegar, tea, coffee, and milk. However, these structures largely remain unexplored and even been eliminated for stability reasons in food industry. Here we report the isolation, characterization, and antioxidant activities of food nanoparticles (NPs) carrying polyphenols from Chinese rice vinegar. Using a gel-chromatography-based isolation protocol, the vinegar was separated into three major fractions. They were identified as spherical NPs (P1), lollipop-like NPs (P2) and spherical microparticles (P3) with average hydrodynamic diameter of 210, 245,1643 nm, separately. The former two fractions accounted for the major parts of dry matter in the vinegar. The P1-NPs fraction was composed of proteins, carbohydrates, and a high number of polyphenols (15 wt%), demonstrated potent antioxidant activity as determined by ABTS and ORAC assays. Moreover, they effectively quenched peroxyl free radicals in peritoneal macrophages and promoted cellular growth. The P2 fraction contained majority of organic acids, esters and mineral elements of the vinegar. It demonstrated the NPs are bioactive units of the rice vinegar, inspiring the development of novel functional nanomaterials with nutraceutical and pharmaceutical applications.

Hyaluronic Acid-Glycine-Cholesterol Conjugate-Based Nanoemulsion as a Potent Vaccine Adjuvant for T Cell-Mediated Immunity

Clinical cases of allergic reaction that are due to excipients containing polyethylene glycol (PEG), a hydrophilic molecule commonly used in drug/vaccine formulations, has attracted much attention in recent years. In order to develop PEG-free adjuvants, we investigated the feasibility of natural ingredients in the human body such as hyaluronic acid in the form of hyaluronic acid-glycine cholesterol (HACH) conjugate as an excipient for vaccine formulation. Interestingly, HACH grafted with ~13 wt.% cholesterol has good water dispersity and can serve as an emulsifier to stabilize the squalene/water interfaces, yielding a milky white and isotropic emulsion (SQ@HACH) after being passed through a high-shear microfluidizer. Our results show that SQ@HACH particles possessed a unimodal average hydrodynamic diameter of approximately 190 nm measured by dynamic light scattering and exhibited good stability upon storage at 4 °C and 37 °C for over 20 weeks. The results of immunogenicity using a mouse model with ovalbumin (OVA) as the antigen revealed that SQ@HACH significantly enhanced antigen-specific immune responses, including the polarization of IgG antibodies, the cytokine secretions of T cells, and enhancement of cytotoxic T lymphocyte (CTL) activation. Moreover, SQ@HACH revealed lower local inflammation and rapidly absorbing properties compared with AlPO4 after intramuscular injection in vivo, indicating the potential functions of the HA-derived conjugate as an excipient in vaccine formulations for enhancement of T cell-mediated immunity.

Trypsinolysis of Polyurethane Particles Based on Сyclodextrin with Encapsulated Moxifloxacin

Abstract-Moxifloxacin encapsulation in polymer cyclodextrin-based particles with an average hydrodynamic diameter of 150--200 nm has led to the formation of potential delivery systems with a degree of moxifloxacin inclusion of more than 80%. Cross-linking of the moxifloxacin-cyclodextrin complexes caused a pronounced slowdown in the release of the drug molecules in acidic media to less than 10% per day. In the presence of trypsin, the drug release was accelerated by 15--20% within 90 min. It was shown by Fourier-transform infrared spectroscopy that this acceleration was due to the partial enzymatic degradation of the urethane bonds of the polymer matrix near the surface of the particles. The results obtained are important for the development of highly effective oral dosage forms of prolonged action. Key words: fluoroquinolones, cyclodextrins, FTIR spectroscopy, trypsin

Coacervate Thermoresponsive Polysaccharide Nanoparticles as Delivery System for Piroxicam

Low water solubility frequently compromises the therapeutic efficacy of drugs and other biologically active molecules. Here, we report on coacervate polysaccharide nanoparticles (CPNs) that can transport and release a model hydrophobic drug, piroxicam, to the cells in response to changes in temperature. The proposed, temperature-responsive drug delivery system is based on ionic derivatives of natural polysaccharides—curdlan and hydroxypropyl cellulose. Curdlan was modified with trimethylammonium groups, while the anionic derivative of hydroxypropyl cellulose was obtained by the introduction of styrenesulfonate groups. Thermally responsive nanoparticles of spherical shape and average hydrodynamic diameter in the range of 250–300 nm were spontaneously formed in water from the obtained ionic polysaccharides as a result of the coacervation process. Their morphology was visualized using SEM and AFM. The size and the surface charge of the obtained objects could be tailored by adjusting the polycation/polyanion ratio. Piroxicam (PIX) was effectively entrapped inside the nanoparticles. The release profile of the drug from the CPNs-PIX was found to be temperature-dependent in the range relevant for biomedical applications.

Avaliação da Capacidade Antimicrobiana de Nanopartículas de Prata Sintetizadas com Mel de Abelha

Nos últimos anos, as nanopartículas de prata (AgNPs) têm atraído muita atenção devido às suas largas aplicações em diferentes campos como biotecnologia, microeletrônica, armazenamento de informação óptica, medicina e conversão de energia. O presente trabalho teve como objetivo sintetizar nanopartículas de prata a partir de amostras de mel de abelhas Apis mellifera produzidos na cidade de Santarém-Pará, Brasil. Além disso, avaliar a atividade antimicrobiana dessas amostras, obtidas em dois períodos distintos (seco e chuvoso), frente a patógenos de interesse clínico: Staphylococcus aureus, Staphylococus epidermidis e Cândida krusei. Todas as amostras apresentaram estabilidade, homogeinidade e diâmetro hidrodinâmico médio de 600 nm, tendo uma grande área superficial. Apresentaram índice de polidispersividade (PdI) médio de 0,36 e 0,28, utilizando méis do período seco e chuvoso, respectivamente. O potencial Zeta foi negativo para 5 amostras do período seco. As linhagens de S. aureus, S. epidermides e C. krusei foram sensíveis à todas as AgNPs sintetizadas, sendo que as CMI para S. aureus e S. epidermides variaram de 0,17 a 10,79 mg mL-1 e para C. krusei de 0,08 a 10,79 mg mL-1. De acordo com estudos as AgNPs sintetizadas se mostram mais ativas em bactérias Gram negativas do que Gram positivo. No entanto, os elevados valores de CMI obtidos neste trabalho estão associados aos maiores tamanhos das nanoparticulas sintetizadas. Palavras-chave: Apis melífera. Staphylococcus aureus. Staphylococus epidermidis. Candida krusei. Abstract In recent years, silver nanoparticles (AgNPs) have attracted a lot of attention due to their wide applications in different fields such as biotechnology, microelectronics, optical information storage, medicine, and energy conversion. The present work aimed to synthesize silver nanoparticles from honey samples from Apis mellifera bees produced in the Santarém-Pará, Brazil. In addition, to evaluate the antimicrobial activity of these samples, obtained in two distinct periods (dry and rainy), against pathogens of clinical interest: Staphylococcus aureus, Staphylococus epidermidis and Candida krusei. All samples showed stability, homogeneity and an average hydrodynamic diameter of 600 nm, with a large surface area. They had an average polydispersity index (PdI) of 0.36 and 0.28, using honeys from the dry and rainy periods, respectively. The Zeta potential was negative for 5 samples from the dry period. The strains of S. aureus, S. epidermides and C. krusei were sensitive to all synthesized AgNPs, with the MIC for S. aureus and S. epidermides ranging from 0.17 to 10.79 mg mL-1 and for C krusei from 0.08 to 10.79 mg mL-1. According to studies, the synthesized AgNPs are more active in Gram negative bacteria than Gram positive. However, the high MIC values obtained in this work are associated with the larger sizes of the synthesized nanoparticles. Keywords: Apis mellifera. Staphylococcus aureus. Staphylococus epidermidis. Candida krusei.

The solvent nature influence on the self-assembly of monosubstituted pillar[5]arenes containing N-(aminoalkyl)amide fragment

Chemistry of macrocyclic compounds is one of the rapidly developing areas of modern organic chemistry. These macrocycles have become widespread due to the high availability of parents compounds, the possibility of synthesis of ligands based on them for highly selective recognition, ion-selective membranes, electrodes, sensors and nanocontainers for targeted drug delivery. Moreover, in the past few years, attention of researchers has again been riveted on mechanically interlocked molecules (rotaxanes and pseudorotaxans) and supramolecular polymers, which can be explained by their potential application as molecular machines and materials. Mechanically interlocked molecules are molecular architectures consisting from two or more components which mechanically bind due to their own topology. Supramolecular polymers are comprise ordered monomer units combined via non-covalent bonds (hydrogen bonds or electrostatic interactions). Thus, this manuscript presents an approach to the synthesis of monosubstituted pillar[5]arenes containing N-(aminoalkyl)amide fragments with various substituent lengths. The formation of self-inclusion complexes by synthesized macrocycles was established by one- and two-dimensional NMR spectroscopy. According to NMR data, only four carbon atoms of the alkyl fragment were included in the macrocyclic cavity regardless of the alkyl chain length. Formation of self-inclusion complexes becomes possible due to the intramolecular hydrogen bond between the NH protons and the oxygen atom of methoxyl fragment, which is confirmed by IR spectroscopy. It was shown by dynamic light scattering that the synthesized pillar[5]arenes in chloroform form aggregates with an average hydrodynamic diameter of 316-640 nm and polydispersity index from 0.18 to 0.20, while polydisperse systems are formed in dimethyl sulfoxide.

Poly(N-Isopropylacrylamide) Microgel Synthesised by Emulsion Polymerization

Smart polymers have been one of the most popularly studied materials owing to their capability to alter physio-chemical behaviour upon exposure to specific external stimuli. The biocompatible thermally responsive poly (N-isopropylacrylamide), PNIPAm shows reversible transition between hydrophilic-hydrophobic characteristics at the vicinity of human physiological temperature has great potential to propel the development of smart tissue engineering scaffold and drug delivery. However, the limited availability and its high cost have dampened the extent of research on this polymer. To address these challenges, the current work demonstrates an economical lab-scale polymerization of crosslinked PNIPAm and the optimised parameters to produce mono-dispersed polymer hydrogel particles were investigated. Characterisation of the synthesized PNIPAm polymer revealed particle size polydispersity index of 0.215, indicative of distribution within the mono-dispersed range, with average hydrodynamic diameter of 346.3 nm. Zeta-potential of the synthesized PNIPAm was found to be -20.6 mV, suggesting an incipient instability in terms of colloidal coagulation. Viscosity of the synthesized PNIPAm (4 wt% concentration in methanol) was 28.6 cP. Thermal gravimetric analysis (TGA) indicated the thermal degradation of main chain PNIPAm fell in the range of 340 to 480°C.

Covalently Cross-Linked Nanoparticles Based on Ferulated Arabinoxylans Recovered from a Distiller’s Dried Grains Byproduct

The purpose of this investigation was to extract ferulated arabinoxylans (AX) from dried distillers’ grains with solubles (DDGS) plus to investigate their capability to form covalently cross-linked nanoparticles. AX registered 7.3 µg of ferulic acid/mg polysaccharide and molecular weight and intrinsic viscosity of 661 kDa and 149 mL/g, correspondingly. Fourier transform infrared spectroscopy (FTIR) was used to confirm the identity of this polysaccharide. AX formed laccase induced covalent gels at 1% (w/v), which registered an elastic modulus of 224 Pa and a content of FA dimers of 1.5 µg/mg polysaccharide. Scanning electron microscopy pictures of AX gels exhibited a microstructure resembling a rough honeycomb. AX formed covalently cross-linked nanoparticles (NAX) by coaxial electrospray. The average hydrodynamic diameter of NAX determined by dynamic light scattering was 328 nm. NAX presented a spherical and regular shape by transmission electron microscopy analysis. NAX may be an attractive material for pharmaceutical and biomedical applications and an option in sustainable DDGS use.

Synthesis of Horseradish Peroxidase-Gold Nanoparticle Conjugate through Green Route

Synthesis of horseradish peroxidase-gold nanoparticle conjugates (HRP-AuNPs) has been studied for the development of biofunctionalized gold nanoparticles (AuNPs) through biogenic route. Herein, horseradish peroxidase enzyme has been used to synthesize gold nanoparticles at room temperature in tricine buffer. The morphology and size distribution of HRP-AuNPs conjugates were obtained by different techniques including dynamic light scattering (DLS), UV-visible (UV-vis) spectrophotometry, scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). The enzyme activity of HRP-AuNP conjugate was compared with free enzyme to determine their catalytic efficiency. The results suggests that HRP-AuNP conjugates are monodisperse particles with average hydrodynamic diameter of 83.93 ± 2.1 nm, zeta potential of about -18.4 ± 1.1 mV and higher enzyme activity towards H2O2 as compared to free horseradish peroxidase. These biofunctionalized gold nanoparticles could act as tag or labeling agent for various applications.