Quick synthesis of lipid-polymer hybrid nanoparticles with low polydispersity using a single-step sonication method

Lipid-polymer hybrid nanoparticle, consisting of a hydrophobic polymeric core and a lipid monolayer shell, represents a new and promising drug delivery platform that has shown controllable particle size and surface functionality, high drug loading yield, sustained drug release profile, and excellent in vitro and in vivo stability. These lipid monolayer-coated polymeric nanoparticles are typically fabricated through a modified nanoprecipitation method, which involves sample heating, vortexing, and solvent evaporation. Herein we report a new and fast method to synthesize lipid-polymer hybrid nanoparticles with controllable and nearly uniform particle size. Using a bath sonication approach, we demonstrate that the whole hybrid nanoparticle synthesis process can be completed in about 5 min compared with a few hours for previous synthesis approaches. The size and polydispersity of the resulting nanoparticles can be readily controlled by tuning the relative concentrations of individual building components. Colloidal stability tests of the synthesized hybrid nanoparticles in PBS buffer and serum show no signs of aggregation over a period of 5 days. The present method improves the production rate of the hybrid nanoparticles by near 20-fold while not compromising the physicochemical properties of the particles. This work may facilitate the bench-to-bedside translation of lipid-polymer hybrid nanoparticles as a robust drug nanocarrier by allowing for fabricating a large amount of these nanoparticles at high production rate.     

Spectroscopic identification of S-Au interaction in cysteine capped gold nanoparticles

This study deals with the synthesis of cysteine capped gold nanoparticles with an average size of 12 nm by borohydride reduction and spectroscopic identification of SAu interaction. We have studied the interaction of thiol with gold nanoparticles in aqueous medium by employing UV-vis, Raman, NMR, and FT-IR spectroscopy. The shifting of gold plasmon resonance in the UV-vis spectra shows the stabilization of gold nanoparticles by cysteine. The disappearance of S-H stretching in both the IR and Raman spectra and the shifting of the NMR signals of the protons in close proximity to the metal center supported the existence of the S-Au interaction in cysteine capped gold nanoparticles. The TEM images shows cysteine capped gold nanoparticles as distinct and spherical entities as compared to free colloidal gold nanoparticles.     

Confinement resonances in photoionization of Xe@C₆₀+

Experimental evidence is presented for confinement resonances associated with photoabsorption by a Xe atom in a C60 cage. The giant 4d resonance in photoionization of Xe is predicted to be redistributed into four components due to multipath interference of photoelectron waves reflected by the cage. The measurements were made in the photon energy range 60-150 eV by merging a beam of synchrotron radiation with a mass/charge selected Xe@C??+ ion beam. The phenomenon was observed in the Xe@C(58)(3+) product ion channel. [corrected]     

Physicochemical characterization of self-assembled poly(∈-caprolactone) grafted dextran nanoparticles

Amphiphilic graft copolymer composed of poly(∈-caprolactone) and dextran was synthesized by ring opening polymerization of ∈-caprolactone initiated through the hydroxyl end of dextran in the presence of stannous 2-ethylhexanoate [Sn (oct)₂] as a catalyst. It has been widely characterized by Fourier transform infrared spectroscopy, ¹H NMR, and thermogravimetric analysis. Nanoparticles were prepared in aqueous medium by co-solvent evaporation technique at room temperature (25 °C). Hydrodynamic diameter and particle size were measured by dynamic light scattering spectroscopy and atomic force microscopy, respectively. Core-shell geometry of polymeric nanoparticle was characterized by fluorescence spectrophotometer using pyrene as a probe. Critical micelle concentration of polymer in triple distilled water decreased from 6.9 × 10⁻⁴ to 8.9 × 10⁻⁴ g/l with increasing hydrophobic moiety. Further, the physiological stability of the nanoparticles in phosphate buffer saline of pH 7.4 at 37 °C was evaluated, which showed promising in drug delivery system.     

Study of electrolyte induced aggregation of gold nanoparticles capped by amino acids

This work reports the electrolyte induced aggregation of gold nanoparticles directly conjugated to amino acid by chemical reduction in aqueous solution. The study was focused on three different classes of amino acids depending on the nature of alpha substituent, viz. l-cysteine, l-leucine, and l-asparagine. The band broadening and the red shift of surface plasmon band with increase in flocculation parameter showed the aggregation of gold nanoparticles with increase in electrolyte concentration and decrease in pH as monitored by UV-visible spectrophotometer. The (1)H NMR spectrum demonstrates that the sulfide bond of cysteine and alpha amino group of leucine and asparagine interact with nanoparticles surface. Furthermore, transmission electron microscope (TEM) and thermogravimetric analysis (TGA) were performed to characterize and to support the fate of stabilization of the gold nanoparticles by amino acid.     

Synthesis of Ptsome: a platinum-based liposome-like nanostructure

We report the synthesis of a phospholipid-like platinous compound and its self-assembling into a liposome-like nanostructure, named Ptsome, as a new delivery system for platinum-based drugs.     

Electron donor solvent effects provide biosensing with quantum dots

A palmitate biosensor that uses the emission intensity of a semiconducting nanoparticle to report palmitate concentration is presented. This method uses electron transfer to quench the emission from a ZnS-coated CdSe nanoparticle. The fatty acid binding pocket of intestinal fatty acid binding protein is used to modulate the electron transfer properties of [Ru(L)(NH3)4](PF6)2 (L = 5-maleimido-1,10-phenanthroline) that is covalently attached within this pocket. Once the metal-complex-modified protein is attached to ZnS-coated CdSe nanoparticles, palmitate addition excludes water from around the metal complex and increases the electron transfer from the metal complex to the valence band hole of the nanoparticle excited state. A 1.6-fold change in emission intensity is observed upon adding a saturated amount (500 nM) of sodium palmitate. The dissociation constant was calculated as 5 nM with a 1 nM lower limit of detection. Since palmitate does not alter the global conformation of intestinal fatty acid binding protein, palmitate-mediated changes in pocket solvation are suggested. This represents a new method in biosensor construction with semiconducting nanoparticles. Including previous conformation-dependent biosensors, there are thousands of potential analytes that can be detected with these strategies. Such biosensors will provide fluorescence contrast imaging reagents for small molecule analytes.     

Technological progress and readiness level of microbial electrosynthesis and electrofermentation for carbon dioxide and organic wastes valorization

In order to achieve a carbon-efficient circular economy, a paradigm shift is required to valorize carbon dioxide (CO₂) and organic wastes into value-added products. Among others, microbial electrosynthesis (MES) and electrofermentation (EF) technologies have shown the potential to contribute to the circular carbon economy. Besides carbon conversion, both technologies can be applied to store excess green energy in the form of valuable transportable chemicals. This article sheds light on the current status of MES and EF technologies by covering the most important literature from the last two years. Recent progress on reactor design and process optimization, scale-up attempts, and a summary of ongoing or completed technology-oriented research projects over the recent years are presented. Furthermore, the key challenges and future research perspectives desired to enable the implementation of the MES technology are also discussed.