Chitosan microparticles as entrapment system for trans- cinnamaldehyde: Synthesis, drug loading, and in vitro cytotoxicity evaluation.

The ionic gelation method was used to study the effect of the crosslinking agent, sodium tripolyphosphate on average particle size (Dp) and zeta potential (ζp) of chitosan microparticles (CSMP) unloaded and loaded with trans-cinnamaldehyde (TCIN). The obtained values of Dp and ζp trend as 117.6 ±â€¯0.4 ≤ Dp ≤ 478.5 ±â€¯3.5 nm and +27.8 ±â€¯1.3 ≤ ζp ≤ +103.5 ±â€¯4.2 mV, respectively. The entrapment efficiency of TCIN in CSMP was 9.1 ±â€¯2.0% and 71.5 ±â€¯2.9% was released after 360 min (pH = 6.5) which reveals a potential anti-cancer activity in acidic environment. Cytotoxicity of TCIN in DMSO (0-50 µM) was evaluated on MDCK and HeLa cell lines and exhibited low effect at either 24 or 48 h of exposure; whereas TCIN-loaded CSMP (0-50 µM) showed, after 24 h of exposure, 67.6 ±â€¯7.0 and 64.5 ±â€¯3.9% cytotoxicity for MDCK and HeLa cell lines, respectively. At 48 h of exposure, TCIN-loaded CSMP achieved 81.1 ±â€¯0.26 and 77.9 ±â€¯4.2% cytotoxicity for MDCK and HeLa cell lines, respectively.

Suberin/trans-Cinnamaldehyde Oil Nanoparticles with Antimicrobial Activity and Anticancer Properties When Loaded with Paclitaxel.

Suberin is a biopolyester that can be extracted from bioresources such as cork trees and may find many applications in food packaging, sealing, and biomedical fields. In this work, we describe for the first time the preparation of suberin nanoparticles using the solvent/antisolvent method. Three different suberin extraction methods from cork trees were used to reveal any differences in the production and properties of the nanoparticles. trans-Cinnamaldehyde, a component of cinnamon essential oil, was added to suberin nanoparticles due to its antimicrobial and/or anticancer properties, and its synergistic effect was studied with the inherent biological properties of suberin. Interestingly, both suberin and suberin/trans-cinnamaldehyde nanoparticles showed very good antimicrobial properties against Staphylococcus aureus and Pseudomonas aeruginosa bacteria, and also against Candida albicans (yeast). Suberin nanoparticles containing trans-cinnamaldehyde loaded with 0.1% w/w paclitaxel provided significant anticancer properties against human hepatocellular carcinoma HepG2 cancer cell lines. This study can be used to explore novel biobased polymers as efficient carriers of essential oils and drugs for infection and cancer therapy, by using minimum amount of drugs and therefore reducing their cytotoxicity and side effects.

Cellulose acetate - essential oil nanocapsules with antimicrobial activity for biomedical applications.

This study aimed to obtain bioactive nanosystems by combining cellulose acetate with three selected essential oils (EOs) to create spherical nanocapsules (NCs) using the solvent/anti-solvent technique. The biological activity of the obtained NCs was promoted by the use of some antimicrobial EOs: Peppermint, Cinnamon and lemongrass which were grafted on the cellulose acetate molecules. Due to their chemistry, such as long hydrocarbon tails and heads with functional groups these EOs were playing also the role of surfactant-like substance facilitating the formation of NCs. A dispersion of NCs was obtained in water and various spectroscopy techniques used to examine their size, morphology and chemistry. Dynamic light scattering calculate the size of the NCs whereas scanning electron microscopy showed their morphology. Fluorescent microscopy and Raman spectroscopy proved the attachment of the EOs in the cellulose acetate molecules. The antimicrobial activity of the obtained nanomaterials was tested against four microbial strains (bacteria: Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and a yeast strain of Candida albicans). The obtained results demonstrated that such NCs can be used in a variety of applications including medical, pharmaceutical recipients and in household products for treating or preventing microbial colonization and biofilm development.

Electrospun Fiber Pads of Cellulose Acetate and Essential Oils with Antimicrobial Activity.

The method of electrospinning was used to create nanofibers made of cellulose acetate (CA) and essential oils (EOs). CA polymer at 15% w/v was dissolved in acetone and then 1% or 5% v/v of EOs was added to the polymer solution. The utilized essential oils were rosemary and oregano oils. Then, the CA/EOs in acetone solution were electrospun, creating micro/nanofibers, approximately 700-1500 nm in diameter. Raman spectroscopy was used to detect the attachment of the EOs in the CA electrospun fibers (ESFs). Scanning electron microscopy was used to study the morphology, topography and dimensions of the ESFs. The formed CA/EOs ESFs are found to have good antimicrobial properties against three common microbial species, frequently found in difficult to treat infections: Bacteria species Staphylococcus aureus, Escherichia coli and the yeast Candida albicans. ESFs with 5% v/v oregano oil with respect to the initial solution, showed the best antimicrobial and anti-biofilm effects due to the potency of this EO against bacteria and fungi, especially for Escherichia coli and Candida albicans. This work describes an effective and simple method to prepare CA/EOs ESFs and opens up many new applications of micro/nanofibers such as improved antimicrobial wound dressings, anti-biofilm surfaces, sensors and packaging alternatives.

A novel ionic amphiphilic chitosan derivative as a stabilizer of nanoemulsions: Improvement of antimicrobial activity of Cymbopogon citratus essential oil.

Amphiphilic chitosans have been recently proposed to improve delivery of poorly soluble drugs. In the present paper a derivative obtained by ionic interaction between chitosan and oleic acid was for the first time studied to physically stabilize o/w nanoemulsions of an antimicrobial essential oil, Cymbopogon citratus (Lemongrass), in a low energy and mild conditions emulsification process. The novel combination of spontaneous emulsification process with chitosan oleate amphiphilic properties resulted in a stable dispersion of a few hundred nanometer droplets. Positive zeta potential confirmed the presence of a chitosan shell around the oil droplets, which is responsible for the nanoemulsion physical stabilization and for the maintenance of chitosan bioactive properties, such as mucoadhesion. Cytotoxicity test was performed on four different cell lines (HEp-2, Caco-2, WKD and McCoy cells) showing biocompatibility of the system. The maintenance and in some cases even a clear improvement in the essential oil antimicrobial activity towards nine bacterial and ten fungal strains, all of clinical relevance was verified for Lemongrass nanoemulsion.

Polylactic Acid-Lemongrass Essential Oil Nanocapsules with Antimicrobial Properties.

Polylactic acid was combined with lemongrass essential oil (EO) to produce functional nanocapsules (NCs). The obtained polylactic acid nanoparticles showed antimicrobial activity both with and without the presence of lemongrass oil; however, the presence of EO improved the activity of the NCs. The presence of lemongrass assisted the formation of well-separated NCs and also provided enhanced antimicrobial properties, since lemongrass is known for its antimicrobial character. Fluorescence microscopy was used to optically observe the nanoparticles and NCs and revealed the attachment of lemongrass oil with the polylactic acid NCs. Dynamic light scattering was used to determine their size. UV absorption was used to determine the exact amount of lemongrass oil found in the polylactic acid-lemongrass oil NCs, which was important for understanding the minimum inhibitory concentration for the antimicrobial experiments. A series of clinically important microbial species were used in the study and the obtained NCs proved to have very good antimicrobial properties against all tested strains. Such NCs can be used for the design of ecological strategies, based on natural alternatives, which may be efficient against severe infections, including those that involve resistant pathogens and biofilms or those with difficult to reach localization.

Antimicrobial Lemongrass Essential Oil-Copper Ferrite Cellulose Acetate Nanocapsules.

Cellulose acetate (CA) nanoparticles were combined with two antimicrobial agents, namely lemongrass (LG) essential oil and Cu-ferrite nanoparticles. The preparation method of CA nanocapsules (NCs), with the two antimicrobial agents, was based on the nanoprecipitation method using the solvent/anti-solvent technique. Several physical and chemical analyses were performed to characterize the resulting NCs and to study their formation mechanism. The size of the combined antimicrobial NCs was found to be ca. 220 nm. The presence of Cu-ferrites enhanced the attachment of LG essential oil into the CA matrix. The magnetic properties of the combined construct were weak, due to the shielding of Cu-ferrites from the polymeric matrix, making them available for drug delivery applications where spontaneous magnetization effects should be avoided. The antimicrobial properties of the NCs were significantly enhanced with respect to CA/LG only. This work opens novel routes for the development of organic/inorganic nanoparticles with exceptional antimicrobial activities.

All natural cellulose acetate-Lemongrass essential oil antimicrobial nanocapsules.

Nanocapsules and nanoparticles play an essential role in the delivery of pharmaceutical agents in modern era, since they can be delivered in specific tissues and cells. Natural polymers, such as cellulose acetate, are becoming very important due to their availability, biocompatibility, absence of toxicity and biodegradability. In parallel, essential oils are having continuous growth in biomedical applications due to the inherent active compounds that they contain. A characteristic example is lemongrass oil that has exceptional antimicrobial properties. In this work, nanocapsules of cellulose acetate with lemongrass oil were developed with the solvent/anti-solvent method with resulting diameter tailored between 95 and 185nm. Various physico-chemical and surface analysis techniques were employed to investigate the formation of the nanocapsules. These all-natural nanocapsules found to well bioadhere to mucous membranes and to have very good antimicrobial properties at little concentrations against Escherichia coli and Staphylococcus aureus.

Effect of Anderson localization on light emission from gold nanoparticle aggregates.

The localization of light known as Anderson localization is a common phenomenon characterizing aggregates of metallic nanostructures. The electromagnetic energy of visible light can be localized inside nanostructures below the diffraction limit by converting the optical modes into nonradiative surface plasmon resonances. The energy of the confined photons is correlated to the size and shape of the nanostructured system. In this work, we studied the photoluminescence dependence of aggregates of 14 nm diameter gold nanoparticles (AuNPs) synthesized by drop-casting a liquid suspension on two different substrates of glass and quartz. The AuNP aggregates were characterized by electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The dielectric constant of the surrounding medium plays a crucial role in determining the aggregate geometry, which affects the Anderson localization of light in the aggregates and hence causes a red-shift in the plasmonic resonance and in the photoluminescence emission. The geometry of the gold nanoparticle aggregates determine the strength of the Anderson localization, and hence, the light emission from the aggregates. The photoluminescence lifetime was found to be dependent on the AuNP aggregate geometry and the dielectric constant of the medium.

Folate-grafted boron nitride nanotubes: possible exploitation in cancer therapy.

Boron nitride nanotubes (BNNTs) have generated considerable interest among the scientific community because of their unique physical and chemical properties. They present good chemical inertness, high thermal stability, and optimal resistance to oxidation, that make them ideal candidates for biomedical applications, in particular as nanovectors for drug, gene and protein delivery into the cells. In this study, BNNTs were prepared through a synthesis based on a chemical vapor deposition (CVD) method, and thereafter chemically functionalized with folic acid. The obtained nanostructures have been characterized by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The characterization showed efficiently functionalized BNNTs of length of about 1 µm. Furthermore, confocal laser microscopy demonstrated that our nanotubes can be fluorescently-traced under appropriate excitation. Thanks to this property, it has been possible to investigate their internalization by HeLa cells through confocal microscopy, demonstrating that the BNNT up-take clearly increases after the functionalization with folate, a result confirmed by inductively coupled plasma (ICP) assessment of boron content inside the treated cell cultures.

Alginate nanofibrous mats with adjustable degradation rate for regenerative medicine.

The broad utilization of electrospun scaffolds of sodium alginate in tissue engineering is strongly limited by their high solubility in aqueous environments and by the difficulty to adjust their degradation dynamics. Here, an alternative strategy to enhance the stability and to control the degradability of alginate nanofibers is described by treating them with trifluoroacetic acid for specific time intervals. It is demonstrated that, by increasing the duration of the acid treatment procedure, a lower degradation rate of the resulting fibers in buffer solutions can be achieved. Furthermore, the produced mats are free from cytotoxic compounds and are highly biocompatible. The properties conferred to the alginate nanofibrous mats by the proposed method are extremely attractive in the production of innovative biomedical devices.

Platelet lysate embedded scaffolds for skin regeneration.

INTRODUCTION: The work presents the development of acellular scaffolds extemporaneously embedded with platelet lysate (PL), as an innovative approach in the field of tissue regeneration/reparation. PL embedded scaffolds should have a tridimensional architecture to support cell migration and growth, in order to restore skin integrity. For this reason, chondroitin sulfate (CS) was associated with sodium alginate (SA) to prepare highly porous systems. METHODS: The developed scaffolds were characterized for chemical stability to γ-radiation, morphology, hydration and mechanical properties. Moreover, the capability of fibroblasts and endothelial cells to populate the scaffold was evaluated by means of proliferation test 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and confocal laser scanning microscopy study. The scaffolds, not altered by sterilization, were characterized by limited swelling and high flexibility, by foam-like structure with bubbles that formed a high surface area and irregular texture suitable for cell adhesion. RESULTS: Cell growth and scaffold population were evident on the bubble surface, where the cells appeared anchored to the scaffold structure. CONCLUSION: Scaffold network based on CS and SA demonstrated to be an effective support to enhance and to allow fibroblasts and endothelial cells (human umbilical vein endothelial cells, HUVEC) adhesion and proliferation. In particular, it could be hypothesized that cell adhesion was facilitated by the synergic effect of PL and CS. Although further in vivo evaluation is needed, on the basis of in vitro results, PL embedded scaffolds seem promising systems for skin wound healing.

PC12 neuron-like cell response to electrospun poly( 3-hydroxybutyrate) substrates.

In the last decade, the importance of topographic properties of extracellular environments has been shown to be essential to addressing cell response, especially when replacing damaged tissues with functional constructs obtained in vitro. In the current study, densely packed sub-micron poly(3-hydroxybutyrate) (PHB) fibres were electrospun with random and parallel orientations. PC12 pheochromocytoma cells that mimic central dopaminergic neurons and represent a model for neuronal differentiation were cultured on collagen-coated fibres to evaluate cell response dependence on substrate topography. Cell adhesion, viability and proliferation, as well as dopamine production were evaluated after three days since seeding. Cell differentiation was examined in terms of neurite number, orientation and length 6 days after administration of nerve growth factor (NGF). Results showed that proliferating PC12 cells secreted a higher quantity of dopamine on fibres with respect to control cultures and as a result, a possible use of PHB fibres was considered for cell transplantation in the central nervous system when local production of dopamine is impaired. Differentiated PC12 cells were characterized by highly aligned and longer neurites on parallel PHB fibres with respect to random fibres, thereby demonstrating the suitability of parallel PHB fibres for further studies in peripheral nervous system regeneration.

Magnetite nanostructures as novel strategies for anti-infectious therapy.

This review highlights the current situation of antimicrobial resistance and the use of magnetic nanoparticles (MNPs) in developing novel routes for fighting infectious diseases. The most important two directions developed recently are: (i) improved delivery of antimicrobial compounds based on a drastic decrease of the minimal inhibition concentration (MIC) of the drug used independently; and (ii) inhibition of microbial attachment and biofilm development on coated medical surfaces. These new directions represent promising alternatives in the development of new strategies to eradicate and prevent microbial infections that involve resistant and biofilm-embedded bacteria. Recent promising applications of MNPs, as the development of delivery nanocarriers and improved nanovehicles for the therapy of different diseases are discussed, together with the mechanisms of microbial inhibition.

All-natural composite wound dressing films of essential oils encapsulated in sodium alginate with antimicrobial properties.

We present natural polymeric composite films made of essential oils (EOs) dispersed in sodium alginate (NaAlg) matrix, with remarkable anti-microbial and anti-fungal properties. Namely, elicriso italic, chamomile blue, cinnamon, lavender, tea tree, peppermint, eucalyptus, lemongrass and lemon oils were encapsulated in the films as potential active substances. Glycerol was used to induce plasticity and surfactants were added to improve the dispersion of EOs in the NaAlg matrix. The topography, chemical composition, mechanical properties, and humidity resistance of the films are presented analytically. Antimicrobial tests were conducted on films containing different percentages of EOs against Escherichia coli bacteria and Candida albicans fungi, and the films were characterized as effective or not. Such diverse types of essential oil-fortified alginate films can find many applications mainly as disposable wound dressings but also in food packaging, medical device protection and disinfection, and indoor air quality improvement materials, to name a few.

Effects of cerium oxide nanoparticles on PC12 neuronal-like cells: proliferation, differentiation, and dopamine secretion.

PURPOSE: Oxidative stress has been found to play a key role in several diseases, that range from cancer to neurodegenerative disorders. Besides traditional anti-oxidant agents, in recent years much attention has been focused on nanotechnological solutions, including cerium oxide nanoparticles (nanoceria). METHODS: Thanks to its extraordinary catalytic properties, nanoceria mimics the activity of superoxide dismutase and of catalase, therefore acting as a reactive oxygen species (ROS) scavenger in many biological contexts. In this paper, we report on nanoceria interactions with PC12 cell line, that represents a valuable model for many features of central dopaminergic neurons. RESULTS: Nanoceria confirmed a strong anti-ROS action but, most interestingly, also showed beneficial effects on both cell differentiation and dopamine production. CONCLUSIONS: Even if deeper examinations will be necessary in order to better clarify the mechanisms at the base of the documented effects, nanoceria demonstrated a significant potential as pharmacological agent in the treatment of neurological disorders.

Bio/non-bio interfaces: a straightforward method for obtaining long term PDMS/muscle cell biohybrid constructs.

Stable surface modifications of polydimethylsiloxane (PDMS) are of crucial importance for the exploitation of the versatile physical properties of silicone in many biological applications. Surface hydrophobic recovery in fact poses severe time limitations to the observation of biological events and, in particular, to cell culturing. A novel method of stable modification of PDMS surface chemistry was therefore elaborated, relying on the use of genipin as a natural low-toxicity cross-linker, and involving free amine moieties. Its effectiveness to long-term cultures was studied by preparation of thin PDMS films with different stiffness. After assessment of surface chemistry and substrate stiffness, H9c2 muscle cells were cultured on the modified films, and differentiating myoblasts were observed for a period of four weeks since differentiation induction. A lower PDMS stiffness increased myotube width and supported a higher actin and myosin colocalization within myotubes, suggesting the achievement of myotube functional maturity. These results provide evidence of the effectiveness of the proposed procedures to PDMS surface chemistry modification. Furthermore, modified PDMS membranes prove to be suitable to several long-term studies of cell behaviour in vitro, including muscle cell contractility investigations.

Human recombinant elastin-like protein coatings for muscle cell proliferation and differentiation.

Recombinant proteins represent a new and promising class of polymeric materials in the field of biomaterials research. An important model for biomaterial design is elastin, the protein accounting for the elasticity of several tissues. Human elastin-like polypeptides (HELPs) have been developed as recombinant versions of elastin with the purpose of enhancing some peculiar characteristics of the native protein, like self-assembling. In this paper, we report on a comparative study of rat myoblasts response to coatings based on two different HELP macromolecules, with respect to control cultures on bare cell culture polystyrene and on a standard collagen coating. Cell behavior was analyzed in terms of adhesion, proliferation and differentiation. The collected data strongly suggest the use of HELPs as excellent biomaterials for tissue engineering and regenerative medicine applications.

Controlled antiseptic release by alginate polymer films and beads.

Biodegradable polymeric materials based on blending aqueous dispersions of natural polymer sodium alginate (NaAlg) and povidone iodine (PVPI) complex, which allow controlled antiseptic release, are presented. The developed materials are either free standing NaAlg films or Ca(2+)-cross-linked alginate beads, which properly combined with PVPI demonstrate antibacterial and antifungal activity, suitable for therapeutic applications, such as wound dressing. Glycerol was used as the plasticizing agent. Film morphology was studied by optical and atomic force microscopy. It was found that PVPI complex forms well dispersed circular micro-domains within the NaAlg matrix. The beads were fabricated by drop-wise immersion of NaAlg/PVPI/glycerol solutions into aqueous calcium chloride solutions to form calcium alginate beads encapsulating PVPI solution (CaAlg/PVPI). Controlled release of PVPI was possible when the composite films and beads were brought into direct contact with water or with moist media. Bactericidal and fungicidal properties of the materials were tested against Escherichia coli bacteria and Candida albicans fungi. The results indicated very efficient antibacterial and antifungal activity within 48 h. Controlled release of PVPI into open wounds is highly desired in clinical applications to avoid toxic doses of iodine absorption by the wound. A wide variety of applications are envisioned such as external and internal wound dressings with controlled antiseptic release, hygienic and protective packaging films for medical devices, and polymer beads as water disinfectants.

A simple approach to covalent functionalization of boron nitride nanotubes.

A novel and simple method for the preparation of chemically functionalized boron nitride nanotubes (BNNTs) is presented. Thanks to a strong oxidation followed by the silanization of the surface through 3-aminopropyl-triethoxysilane (APTES), BNNTs exposing amino groups on their surface were successfully obtained. The efficacy of the procedure was assessed with EDS and XPS analyses, which demonstrated a successful functionalization of ~15% boron sites. This approach opens interesting perspectives for further modification of BNNTs with several kinds of molecules. Since, in particular, biomedical applications are envisaged, we also demonstrated in vitro biocompatibility and cellular up-take of the functionalized BNNTs.