5,10,15-Tris(pentafluorophenyl)corrole as highly selective neutral carrier for a silver ion-sensitive electrode

A new highly selective silver(I) electrode was prepared with a PVC membrane using 5,10,15-tris(pentafluorophenyl)corrole as an electroactive material, 2-nitrophenyl octyl ether (o-NPOE) as a plasticizer and sodium tetraphenylborate (NaTPB) as an additive in the percentage ratio of 3:3:62:32 (corrole:NaTPB:o-NPOE:PVC, w:w). The electrode exhibited linear response with a near Nernstian slope of 54.8 mV/decade within the concentration range of 5.1 × 10⁻⁶ to 1.0 × 10⁻¹ M silver ions, with a working pH range from 4.0 to 8.0, and a fast response time of <30 s. Selectivity coefficients for Ag(I) relative to a number of interfering ions were investigated. The electrode is highly selective for Ag(I) ions over a large number of mono-, bi-, and tri-valent cations. Common interferents like Hg²⁺ and Cd²⁺ show very low interfering effect on the silver assay, which is valuable property of the proposed electrode. Several electroactive materials and solvent mediators have been compared and the experimental conditions were optimized. The sensor was applied to the determination of silver in real ore samples with satisfied results.     

Synthesis and polymerisation of lipophilic peptide nucleic acids derived from stearic acid and pentacosa-10,12-diynoic acid

The adenine, cytosine and thymine peptide nucleic acid (PNA) monomers and PNA T₁₀ oligomers bearing either a diacetylenic or stearoyl moiety at the N- or C-terminus have been successfully prepared. The resulting thymine monomeric and T₁₀-mer derivatives have been subsequently incorporated into polydiacetylene-containing liposomes.     

A novel thiocyanate-selective electrode based on a zinc–phthalocyanine complex

A novel thiocyanate (SCN⁻)-selective PVC membrane electrode based on a zinc-phthalocyanine (ZnPc) complex as neutral carrier is described. The membrane electrode containing ZnPc with 5.1% (w/w) ionophore, 29.2% (w/w) PVC, and 65.7% (w/w) 2-nitrophenyl octyl ether (o-NPOE) as plasticizer displayed an anti-Hofmeister selectivity sequence , and exhibited near-Nernstian potential response to thiocyanate ranging from about 1.0×10⁻¹ to 1.0×10⁻⁶ mol L⁻¹ with a detection limit of 7.5×10⁻⁷ mol L⁻¹ and a slope of 58.1±0.5 mV per decade in pH 3.0 phosphate buffer solution at 25 °C. This preferential response is believed to be associated with the unique coordination between the central metal of the carrier and thiocyanate.      

Homogeneous chemiluminescence system in neutral and near neutral aqueous solution with ClO2 as oxidant and its analytical application

Using ClO₂ as chemiluminescence (CL) oxidant, a novel homogeneous CL system in neutral and near neutral aqueous solution is proposed in this paper. ClO₂ could oxidize sulfite in pH 5.0–8.5 acetate buffer to produce CL emission, and pipemidic acid could sensitize the CL system. The ClO₂–SO₃²⁻–pipemidic acid reaction was used as a model CL system and explored the possibility of highly active and eco-friendly ClO₂ being used as CL oxidant in neutral and near neutral aqueous solution. Combined with flow-injection analysis, the proposed CL system was applied to the automated dissolution testing of pipemidic acid tablet. Compared with the common strong acidic or strong basic CL system, this proposed CL owns its advantages.     

Deformable liposomes containing alkylcarbonates of γ-cyclodextrins for dermal applications

Liposomes made with hydrogenated soya lecithin (HPC) mixed with dodecylcarbonate γ-cyclodextrin (C12CD) at 20:1, 10:1 and 5:1 w/w ratios were prepared by the solvent evaporation method. C12CD had emulsifying properties and the possibility of producing deformable liposomes, as topical delivery system of progesterone (PG), was evaluated. Liposome size, deformability and drug entrapment were determined and the interaction between C12CD and HPC was investigated using differential scanning calorimetry (DSC). The size and the amount of PG loaded in the liposomes depended on the lipid:C12CD ratio: the smallest liposomes were obtained using 20:1 ratio and the maximum drug entrapment at 5:1 ratio. DSC analysis suggested that C12CD interacted with liposomes disrupting and fluidizing the lipid bilayer. PG transepidermal permeation through intact pig skin and PG skin uptake from deformable liposomes were assessed and compared to the values obtained from aqueous suspension and conventional liposomes. The PG permeations were negligible for all systems, while skin uptake increased for liposomes containing C12CD. This was attributed to the deformability and to the increase in the drug entrapment efficiency of these liposomes. The use of C12CD in liposome formulations can improve PG topical therapy.     

Ultrasound-mediated drug delivery using liposomes modified with a thermosensitive polymer

Ultrasound-mediated drug delivery was established using liposomes that were modified with the thermosensitive polymer (TSP) poly(NIPMAM-co-NIPAM), which sensitized the liposomes to high temperatures. TSP-modified liposomes (TSP liposomes) released encapsulated calcein under 1 MHz ultrasound irradiation at 0.5 W/cm² for 120 s as well as the case under incubation at 42 °C for 15 min. In addition, uptake of the drug released from TSP liposomes by cancer cells was enhanced by ultrasound irradiation. In a cell injury assay using doxorubicin (DOX)-loaded TSP liposomes and ultrasound irradiation, cell viability of HepG2 cells at 6 h after ultrasound irradiation (1 MHz, 0.5 W/cm² for 30 s) with DOX-loaded TSP liposomes (TSP/lipid ratio = 1) was 60%, which was significantly lower than that of the control conditions such as DOX-loaded TSP liposomes alone and DOX-loaded intact liposomes under ultrasound irradiation.     

Targeted and ultrasound-triggered drug delivery using liposomes co-modified with cancer cell-targeting aptamers and a thermosensitive polymer

In this study, we demonstrated the feasibility of targeted and ultrasound-triggered drug delivery using liposomes co-modified with single stranded DNA aptamers that recognized platelet-derived growth factor receptors (PDGFRs) as targeting ligands for breast cancer cells and poly(NIPMAM-co-NIPAM) as the thermosensitive polymer (TSP) to sensitize these liposomes to high temperature. TSP-modified liposomes (TSP liposomes) released encapsulated calcein under 1 MHz ultrasound irradiation for 30 s at 0.5 W/cm² as well as the case under incubation for 5 min at 42 °C. Ultrasound-triggered calcein release from TSP liposomes was due to an increased local temperature, resulting from cavitation bubble collapse induced by ultrasound, and not due to an increase in the bulk medium temperature. Liposomes modified with PDGFR aptamers (APT liposomes) bound to MDA-MB-231 human breast cancer cells through PDGFR aptamers; however, they did not bind to primary human mammary epithelial cells (HMECs). The binding of APT liposomes was greatest for MDA-MB-231 cells, followed by MCF-7, WiDr, and HepG2 cancer cells. In a cell injury assay using doxorubicin (DOX)-loaded APT/TSP liposomes and ultrasound irradiation, cell viability of MDA-MB-231 at 24 h after ultrasound irradiation (1 MHz for 30 s at 0.5 W/cm²) with DOX-loaded APT/TSP liposomes was 60%, which was lower than that with ultrasound irradiation and DOX-loaded TSP liposomes or with DOX-loaded APT/TSP liposomes alone.     

Synthesis,Properties, and Applications of Amino Acids Based Surfactants: A Review

Amino acids based surfactants belong to the class of surfactants with high biodegradability, low toxicity and excellent surface active properties. They possess excellent emulsifying, detergency properties and form fine lather. These surfactants are environment friendly, mild to skin and eyes, and have hard water tolerance. This article reviews types, synthesis, various surface properties such as cmc (critical micelle concentration), surface tension, phase behavior, Krafft temperature, and interfacial adsorption of these surfactants. The biological properties such as antimicrobial activity, aquatic toxicity, biodegradability and hemolytic activity have also been focused. The various applications of amino acid based surfactants in the area of life sciences such as gene transfection, formation of liposomes, and drug delivery systems have also been reviewed.     

Synthesis and characterization of complexes of organotin(IV) with 2-thiazoline-2-thione

The reaction of 2-thiazoline-2-thione (TZDSH) with SnR₂Cl₂ (R=Ph 1, Me 2, Bu 3) in dry ethanol in the presence of sodium ethoxide leads to [SnR₂(C₃H₄NS₂)₂] (1, 2, and 3), respectively. Reaction between TZDSH and SnPh₂Cl₂ in dichloromethane and dry ethanol in an inert atmosphere produces [SnPh₂Cl₂(C₃H₅NS₂)₂] (4). The yields of the products were over 80%. These new complexes have been characterized by IR, UV-Vis, multinuclear (¹H, ¹³C, and ¹¹⁹Sn) NMR spectroscopy, and mass spectrometry, as well as elemental analysis.     

Citrate selectivity of poly(neutral red) electropolymerized films

The synthesis and the spectroscopic and potentiometric characterization of electropolymerized films obtained from neutral red (NR) on Pt surface are described. FT Raman and NMR spectroscopy were used for evaluation of the resulting poly(NR) layers. Then potentiometry was applied to study the characteristics of the complexation of carboxylates with the poly(NR) films. A potentiometric poly(NR) sensor showing high selectivity for citrate anion was employed for its determination in soft drinks.