Undecylenic Acid Research Articles

Performance optimisation of porous silicon rugate filter biosensor for the detection of insulin

A porous silicon rugate filter (pSiRF) insulin biosensor has been constructed and systematically optimised by investigating the effects of specific experimental parameters. The pSiRF biosensor is based on an optical sensing platform using interferometric reflectance spectroscopy (IRS) to monitor insulin binding to a surface-anchored insulin binding aptamer (IBA) within the pores. The aim of this study was to determine the optimal fabrication to elicit the maximum sensor response, lowest limit of detection (LOD) and fastest response time. Thermal hydrosilylation with undecylenic acid was used as a base surface modification, with IBA attached through formation of an amide bond. The following pSiRF fabrication conditions were investigated; porous film thickness and IBA concentration in the conjugation solution. The effect of solution flow speed over the pSiRF during insulin biosensing was also investigated in an effort to improve the performance. The optimised pSiRF biosensor was successfully applied for the detection of insulin secreted from human islets on stimulation with glucose. Finally, as a proof of concept, insulin sensing in the presence of human islets on the pSiRF surface was performed to demonstrate the robust performance of the biosensor and the potential for in-situ insulin biosensing.

Synthesis, photoluminescence, and energy transfer mechanism of a reactive Eu(III)-complex used in white light-emitting diodes

A reactive Eu(III)-complex Eu(TTA)3 ( UA ) was synthesized with 2-thenoyltrifluoroacetone (TTA) as primary ligand and undecylenic acid (UA) as active ligand. The structure of the complex was characterized by elemental analysis, FT-IR spectra, and UV–vis absorption spectra. The results indicate that the Eu(III) ion is successfully coordinated with primary ligand TTA and active ligand UA. Fluorescence spectra suggest that the complex exhibits excellent red emission of Eu(III) ion with a peak at 611 nm being monitored at 365 nm of near ultraviolet. Meanwhile, the complex has also shown a long fluorescence lifetime of 1.4259 ms and a high quantum yield of 86.7%. The singlet and triplet energy levels for the ligands of rare earth complexes were calculated using Gaussian 03 program package. Intramolecular energy transfer diagram was established and an energy transfer process following Dexter electron exchange mechanism was demonstrated, which provides the experimental data and theoretical foundation for the development of high-performance luminescent materials. The result of TGA shows that the complex keeps stable at 156°C or below. All the results demonstrate that the reactive Eu(III)-complex can be used as the red-light material in white light-emitting diodes phosphor.

Hexosomes with Undecylenic Acid Efficient against Candida albicans.

Due to the growing issues with fungal infections, especially with Candida, there is still a need to develop novel anti-Candida materials. One of the known antifungal agents is undecylenic acid (UA), which still cannot be efficiently used due to its oily nature, and thus limited solubility. By taking advantage of the properties of UA, we developed an emulsion with hexagonal phase, i.e., hexosomes, whose structure and morphology was studied by small-angle X-ray scattering and cryo-electron microscopy, respectively. The presence of UA in the hexosome was confirmed by spectroscopy. Moreover, we studied the anti-Candida effect of hexosomes and their cytotoxicity toward human cells. The minimal inhibitory concentration for the 50% and 90% Candida-growth reduction was found at 0.01 and 0.16 wt % hexosomes, respectively (i.e., 2 and 32 pghex/C.a.cell, respectively). The percentage of metabolically active Candida was reduced by 72–96% at hexosome concentrations of 1.0–8.2 pghex/C.a.cell as compared to untreated Candida. Furthermore, at the same concentration range the embedded filamentation test after 24 and 48 h showed the inhibition of both the filamentation and growth of Candida, while the preliminary toxicity test showed that hexosomes were nontoxic for human cells. All these render the here-developed hexosomes with UA efficient and promising anti-Candida agents.

Fungicidal PMMA-Undecylenic Acid Composites.

Undecylenic acid (UA), known as antifungal agent, still cannot be used to efficiently modify commercial dental materials in such a way that this affects Candida. Actually, issues with Candida infections and fungal resistance compromise the use of Poly(methyl-methacrylate) (PMMA) as dental material. The challenge remains to turn PMMA into an antifugal material, which can ideally affect both sessile (attached) and planktonic (free-floating) Candida cells. We aimed to tackle this challenge by designing PMMA-UA composites with different UA concentrations (3–12%). We studied their physico-chemical properties, the antifungal effect on Candida and the cytotoxicity toward human cells. We found that UA changes the PMMA surface into a more hydrophilic one. Mainly, as-preparation composites with ≥6% UA reduced sessile Candida for >90%. After six days, the composites were still efficiently reducing the sessile Candida cells (for ~70% for composites with ≥6% UA). Similar results were recorded for planktonic Candida. Moreover, the inhibition zone increased along with the UA concentration. The antifungal effect of UA was also examined at the surface of an UA-loaded agar and the minimal inhibitory concentration (MIC90) was below the lowest-studied 0.0125% UA. Furthermore, the embedded filamentation test after 24 h and 48 h showed complete inhibition of the Candida growth at 0.4% UA.

Synthesis of Macroheterocycles with Nitrogen-Containing and Ester Fragments from Undecylenic Acid

Synthesis of Macroheterocycles with Nitrogen-Containing and Ester Fragments from Undecylenic Acid

Pharmacological Potentials, Characterization and Fatty Acids Profile of Persea americana Mill. (Avocardo) Seed Oil Using Gas Chromatography-Mass Spectroscopy

In this study, Avocado seed oil was extracted using sohxlet apparatus, n-hexane: chloroform (30:70) at 70°C for 3 h, characterized and the pharmacological potentials assessed. The percentage oil yield was 36.93%, brown in colour and remained liquid at room temperature. The acid, peroxide and iodine values were 7.86 mg/KOH/g, 42.11 meq/ Kg-1 and 33.21 mg/100 g respectively. The identified fatty acids included Dodecanoic acid (1.05%), tetradecanoic acid (0.86%), n-hexadecanoic acid (13.19%), hexadecanoic acid (4.12%), 9,12-octadecanoic acid (0.28%), 11-octadecanoic acid (0.45%), oleic acid (40.33%), n-hexadecanoic acid (9.69%), 1,E-11-Z-13-octadecatriene (11.45%), 1,E-11-Z-13octadecatriene (6.78%), undecylanic acid (6.31%), palmitaldehyde diisopentylacetal (1.14%), 9-octadecanal (1.18%) and (E)-13-docosenoic acid (3.17%). The presence of fatty acids such as undecylenic acid, oleic acid and other essential fatty acids suggests the seed oil could possess important pharmacological properties.

Green enzymatic production of glyceryl monoundecylenate using immobilized Candida antarctica lipase B

ABSTRACTEnzymatic synthesis of glyceryl monoundecylenate (GMU) was performed using indigenously immobilized Candida anatarctica lipase B preparation (named as PyCal) using glycerol and undecylenic acid as substrates. The effect of molar ratio, enzyme load, reaction time, and organic solvent on the reaction conversion was determined. Both batch and continuous processes for GMU synthesis with shortened reaction time were developed. Under optimized batch reaction conditions such as 1:5 molar ratio of undecylenic acid and glycerol, 2 h of reaction time at 30% substrate concentration in tert-butyl alcohol, conversion of 82% in the absence of molecular sieve, and conversion of 93% in the presence of molecular sieve were achieved. Packed bed reactor studies resulted in high conversion of 86% in 10-min residence time. Characterization of formed GMU was performed by FTIR, MS/MS. Enzymatic process resulted in GMU as a predominant product in high yield and shorter reaction time periods with GMU content of 92% and DAG content of 8%. Optimized GMU synthesis in the present study can be used as a useful reference for industrial synthesis of fatty acid esters of glycerol by the enzymatic route.

New formulation for topical treatment of onychomycoses.

In order to treat onychomycosis, topical and systemic medications are available. The choice of a systemic or topic treatment depends on numerous factors, such as patient's age, the presence of comorbidity, responsible fungal species, the clinical form of onychomycosis, its location (fingernails or toenails), the number of nails affected and the percentage of the nail plate infected. As for topical medications, given that nail plate has an insufficiently permeable structure, it is necessary to use appropriate formulae that create in the surface of the nail plate a film able, in turn, to function both as an active ingredient's deposit and moisturising agent in nail's superficial layers in order to facilitate the spread of the active ingredient. In this manuscript, we wanted to evaluate the effectiveness and tolerability rate of a new topical formulation (Miconal Nails®, Morgan srl, Vicenza, Italy) composed of hydrogenated castor oil, hydroxyethyl cellulose, and other ingredients (urea, climbazole, piroctone olamine, undecylenic acid). We selected 25 patients of both sexes whose median age was between 20 and 70 years, and were affected by onychomycosis in a single toe. Their onychomycosis was a distolateral subungual type (with a <50% invasion of nail plate and sparing of lunula) and white superficial. The treatment was evaluated with the following possible outcomes: complete healing, improvement, stationarity, worsening. Patients were 11 female subjects and 14 male subjects, whose median age was 45. A complete healing was achieved in 15 patients. In 3 cases the clinical presentation appeared unchanged with a persistence of mycological evidence. The response to the treatment was assessed as improvement in 7 patients. In our experience, this new product is an effective weapon that enhances the therapeutic selection of topical formulae for treating onychomycosis. If used alone in the cases that meet inclusion criteria for topical treatment, it allowed us to achieve a complete healing just with a 5-month treatment in 60% of cases, data that reached 76% on the follow-up visit.

Properties of polymers as a nanoscale material for fibers in leather

Hyperbranched polymers, an innovative class of nano-polymers, could enhance the properties of fibers owning to their unique structures. In this study, the ester compound (HPAE) of 3-(bis(2-hydroxyethyl)amino)propionic acid and pentaerythritol was treated with undecylenic acid to obtain novel hyperbranched multiterminal alkenyl polymers (HPAE-UAs). The sizes of the HPAE-UAs could be controlled conveniently from 400 to 1300 nm by adjusting the capped fraction of the hydroxyl groups with undecylenic acids. The molecular structures of HPAE-UAs were characterized by means of FT-IR and 1H-NMR. Then, the effect of the HPAE-UAs on the structures, thermal, and mechanical properties of the wet blue leather were investigated. TEM and SEM demonstrated that the spacing between fibers was enlarged. The thermogravimetric analysis showed that the residual volume of leather could reach up to 30.3 % at about 500 °C. Furthermore, the shrinkage temperature increased to 89.4 °C. It was found that the HPAE-UAs used in leather could improve the thermal performance, physical and mechanical properties. All of these results indicate that HPAE-UAs can be used as a fatliquor with retanning in leather process.

Neuroprotective action of undecylenic acid (UDA) encapsulated into PCL nanocarriers

The main goal of the presented research was to investigate the biocompatibility of polycaprolactone (PCL)-based nanoparticles and to evaluate the neuroprotective action of the encapsulated, water-insoluble neuroprotective substance − undecylenic acid (UDA). The neuroprotectant-loaded nanoparticles (NPs) were prepared from polymer containing toluene based nanoemulsions formed by the phase inversion composition (PIC) technique followed by solvent evaporation. Two types of PCL-based UDA-loaded nanoparticles were synthesized: PCL and PCL-PEG (using poly(ethylene glycol)-block-poly(ε−caprolactone) methyl ether). The average size of PCL/UDA NCs was around 120nm and for PCL-PEG/UDA around 150nm. The concentration of both types of NCs was similar: 2×1010 particles ml−1 and the zeta potential of UDA-loaded PCL and PCL-PEG NCs −24mV and −21mV respectively. Biocompatibility of synthesized nanocarriers was evaluated in the SH-SY5Y human neuroblastoma cell line using cell viability/toxicity assays (MTT reduction, LDH release). The PCL and PCL-PEG nanocarriers at concentration 0.5×1010 particlesml−1 did not show deleterious effects on human neuroblastoma cells line. The neuroprotection studies revealed that UDA loaded in PCL or PCL-PEG nanocarriers retained its neuroprotective potential against Staurosporine-evoked SH-SY5Y cell damage.

Characteristic analysis of Fe3O4 nanoparticles modified by oleic acid and undecylenic acid

ABSTRACTCarbonization of magnetic polymer microspheres is one of the methods for the preparation of magnetic carbon materials. Fe3O4 magnetic particle characteristics considerably influence the magnetic content and size distribution of magnetic polymer microspheres. The characteristics of Fe3O4 nanoparticles modified by oleic acid (OA) and undecylenic acid (UA) were analyzed by X-ray diffraction, Fourier transform infrared, scanning electron microscopy, dynamic laser light scattering, thermogravimetry/differential thermogravimetry, vibrating sample magnetometer, and water contact angle. Fe3O4 nanoparticles modified by OA and UA are nearly spherical and exhibit superparamagnetism. Fe3O4 particle size and saturation magnetization are slightly influenced by the OA and UA composition. OA and UA both are chemically adsorbed onto Fe3O4 as bidentate chelates. OA shows easier adsorption onto Fe3O4 than UA. OA groups have an expanded arrangement on OA@Fe3O4, whereas UA groups have a condensed arrangement on UA@Fe3O4. Particle lipophilicity decreases and particle clustering increases with decreasing OA content and increasing UA content on OA-UA@Fe3O4 nanoparticles.

Anti-Markovnikov Hydrobromination of Alkenes

Alkyl bromides are key intermediates in many multi-step organic syntheses and are commonly synthesized from the hydrobromination of alkenes. While both the Markovnikov and anti-Markovnikov product can theoretically be produced from either the electrophilic addition mechanism or the radical mechanism, the electrophilic addition mechanism produces predominately the Markovnikov product while the radical mechanism mainly produces the anti-Markovnikov product. The regiochemistry of this reaction is controlled by the absence or presence of radicals. The addition of UV radiation or peroxide results in radical formation which yields predominately the anti-Markovnikov product. To improve the synthesis of the anti-Markovnikov product, conditions need to be modified to favor the production of radicals over carbocations. The objective of this research is to develop an efficient synthesis of the anti-Markovnikov alkyl bromides by generating hydrobromic acid from the in situ hydrolysis of phosphorous tribromide with water. Increasing the amount of phosphorous tribromide increases both the percent conversion and percent yield of the anti-Markovnikov alkyl bromide from both 1-octene and undecylenic acid. Based on the data, 1-octene is consumed within 2 hours with percent conversion greater than 80% anti-Markovnikov product when an excess of phosphorus tribromide is used. A minimum ratio of 1.6 mmol of hydrobromic acid to undecylenic acid consumes all of the alkene with percent yields ranging from 80-100%.

Optimizing the reaction conditions for the anti-Markovnikov hydrobromination of alkenes.

The addition of hydrobromic acid to an alkene is a fundamental organic reaction with unsymmetrical alkenes yielding two products, Markovnikov and anti-Markovnikov alkyl bromide. Both of these products can theoretically be produced from either the electrophilic addition mechanism or the radical mechanism. The electrophilic addition mechanism produces predominately the Markovnikov alkyl bromide while the radical mechanism produces predominately the anti-Markovnikov alkyl bromide. The overall objective of this research is to develop a novel synthesis of the anti-Markovnikov alkyl bromide through a radical mechanism from the in situ generation of hydrobromic acid from phosphorus tribromide and water. Results from 1-octene and undecylenic acid show a strong correlation between the volume of the solvent and the percent anti-Markovnikov alkyl bromide produced. For 1-octene a stir time of 24 hours is preferable over 2 hours to improve the percent yield of alkyl bromides. Additional stir time beyond 24 hours was not beneficial as the percent yields remained comparable. While stir times of both 2 and 24 hours had comparable percent yields for undecylenic acid, the stir time of 24 hours had a stronger correlation between the volume of solvent and the percent conversion to the anti-Markovnikov alkyl bromide. This procedure appears to be a viable synthesis of the anti-Markovnikov alkyl bromide, but additional trials with other alkenes need to be performed.

UV-curable hyperbranched urethane acrylate oligomers modified with different fatty acids

The UV-curable hyperbranched urethane acrylate oligomers modified with different fatty acids including undecylenic acid (UCA), myristic acid (MA), and oleic oil (OA) are successfully synthesized in this paper. The prepared oligomers are characterized using FTIR, 1HNMR, GPC, DSC, and TGA. The properties of the UV-curable films formed by these oligomers are also determined. The effects of the oligomer structures including double bond content, chain length of the modified fatty acids, and content of fatty acid and polyurethane acrylate segment, on the properties of the cured films, which are tack-free time, pencil hardness, impact resistance, adhesion, and boiling water resistance, are discussed in detail. It is observed that the curing film formed by HBPE2-60%UCA-20%PUA shows the best comprehensive performance among the films prepared in this study.

Self-Assembling Behavior of Glycerol Monoundecenoate in Water.

The self-assembling properties of glycerol esters in water are well known. Still, few data on glycerol monoesters of undecylenic acid are available. The aim of this study was to highlight the behavior of glycerol monoundecenoate (GM-C11:1) in different diluted and concentrated states. Its self-assembling properties in water and upon solid inorganic surfaces were investigated in the diluted state using surface tension experiments, atomic force microscopy, and cryogenic transmission electron microscopy studies. In the concentrated state, the gelling properties in the presence of water were investigated using polarized light microscopy, differential scanning calorimetry (DSC), and small-angle X-ray scattering (SAXS) experiments. GM-C11:1 at 100 mg/L self-assembles at the liquid/air interfaces as aggregates of approximately 20 nm in diameter, organized into concentric forms. These aggregates are spherical globules composed of several molecules of GM-C11:1. At higher concentrations (1000 and 104 mg/L), GM-C11:1 is able to uniformly coat liquid/air and liquid/solid interfaces. In bulk, GM-C11:1 forms spontaneously aggregates and vesicles. In a more concentrated state, GM-C11:1 assembles into lamellar Lβ and Lα forms in water. By cross-referencing SAXS and DSC findings, we were able to distinguish between interlamellar water molecules strongly bound to GM-C11:1 and other molecules remaining unbound and considered to be "mobile" water. The percentage of water strongly bound was proportional to the percentage of GM-C11:1 in the system. In this case, GM-C11:1 appears to be an effective molecule for surface treatments for which water retention is important.

Receptor-Mediated Surface Charge Inversion Platform Based on Porous Silicon Nanoparticles for Efficient Cancer Cell Recognition and Combination Therapy.

Negatively charged surface-modified drug delivery systems are promising for in vivo applications as they have more tendency to accumulate in tumor tissues. However, the inefficient cell uptake of these systems restricts their final therapeutic performance. Here, we have fabricated a receptor-mediated surface charge inversion nanoparticle made of undecylenic acid modified, thermally hydrocarbonized porous silicon (UnTHCPSi) nanoparticles core and sequentially modified with polyethylenimine (PEI), methotrexate (MTX), and DNA aptamer AS1411 (herein termed as UnTHCPSi-PEI-MTX@AS1411) for enhancing the cell uptake of nucleolin-positive cells. The efficient interaction of AS1411 and the relevant receptor nucleolin caused the disintegration of the negative-charged AS1411 surface. The subsequent surface charge inversion and exposure of the active targeting ligand, MTX, enhanced the cell uptake of the nanoparticles. On the basis of this synergistic effect, the UnTHCPSi-PEI-MTX@AS1411 (hydrodynamic diameter is 242 nm) were efficiently internalized by nucleolin-positive MDA-MB-231 breast cancer cells, with an efficiency around 5.8 times higher than that of nucleolin-negative cells (NIH 3T3 fibroblasts). The receptor competition assay demonstrated that the major mechanism (more than one-half) of the internalized nanoparticles in MDA-MB-231 cells was due to the receptor-mediated surface charge inversion process. Finally, after loading of sorafenib, the nanosystem showed efficient performance for combination therapy with an inhibition ratio of 35.6%.

Controlled doping by self-assembled dendrimer-like macromolecules

Doping via self-assembled macromolecules might offer a solution for developing single atom electronics by precisely placing individual dopants at arbitrary location to meet the requirement for circuit design. Here we synthesize dendrimer-like polyglycerol macromolecules with each carrying one phosphorus atom in the core. The macromolecules are immobilized by the coupling reagent onto silicon surfaces that are pre-modified with a monolayer of undecylenic acid. Nuclear magnetic resonance (NMR) and X-ray photoelectron spectroscopy (XPS) are employed to characterize the synthesized macromolecules and the modified silicon surfaces, respectively. After rapid thermal annealing, the phosphorus atoms carried by the macromolecules diffuse into the silicon substrate, forming dopants at a concentration of 1017 cm−3. Low-temperature Hall effect measurements reveal that the ionization process is rather complicated. Unlike the widely reported simple ionization of phosphorus dopants, nitrogen and carbon are also involved in the electronic activities in the monolayer doped silicon.

Fatty Acid Characterization from Flowers of Tulipa Systola Stapf. Using Gas Chromatography-Mass Spectrometry (GC-MS)

The structural analysis of fatty acid mixtures by gas chromatography-mass spectrometry (GC-MS) has been characterized from Tulipa systola Stapf. Flowers, wild plant growing in Kurdistan region-Iraq. The fatty acids of the lipid fraction were mainly saturated fatty acids, the highest value recorded for isopropyl palmitic acid methyl ester (47.02%), glycerol α-palmitic acid methyl ester (19.66%) and stearic acid methyl ester (8.64%). In addition, two unsaturated fatty acids that characterized were oleic acid methyl ester (6.95%) and undecylenic acid methyl ester (2.22%).

Sensitive detection of copper ions via ion-responsive fluorescence quenching of engineered porous silicon nanoparticles.

Heavy metal pollution has been a problem since the advent of modern transportation, which despite efforts to curb emissions, continues to play a critical role in environmental pollution. Copper ions (Cu2+), in particular, are one of the more prevalent metals that have widespread detrimental ramifications. From this perspective, a simple and inexpensive method of detecting Cu2+ at the micromolar level would be highly desirable. In this study, we use porous silicon nanoparticles (NPs), obtained via anodic etching of Si wafers, as a basis for undecylenic acid (UDA)- or acrylic acid (AA)-mediated hydrosilylation. The resulting alkyl-terminated porous silicon nanoparticles (APS NPs) have enhanced fluorescence stability and intensity, and importantly, exhibit [Cu2+]-dependent quenching of fluorescence. After determining various aqueous sensing conditions for Cu2+, we demonstrate the use of APS NPs in two separate applications – a standard well-based paper kit and a portable layer-by-layer stick kit. Collectively, we demonstrate the potential of APS NPs in sensors for the effective detection of Cu2+.

Characterization of alendronic- and undecylenic acid coated magnetic nanoparticles for the targeted delivery of rosiglitazone to subcutaneous adipose tissue

Obesity is a state of positive energy balance where excess white adipose tissue accumulates to the detriment of metabolic health. Improving adipocyte function with systemic administration of thiazolidinediones (TZDs) improves metabolic outcomes in obesity, however TZD use is limited clinically due to undesirable side effects. Here we evaluate magnetic nanoparticles (MNPs) as a tool to target rosiglitazone (Rosi) specifically to adipose tissue. Results show Rosi can be adsorbed to MNPs (Rosi-MNPs) with hydrophobic coatings for which we present binding and release kinetics. Rosi adsorbed to MNPs retained the ability to induce PPARγ target gene expression in cells. Biodistribution analysis of radiolabeled Rosi-MNPs revealed a fat-implanted magnet significantly enhanced localization of Rosi to the targeted adipose tissue when administered by subcutaneous injection to obese mice. We propose MNPs for targeted delivery of anti-diabetic agents to superficially located subcutaneous adipose tissue.