Facile fabrication and property of biocompatible and biodegradable cellulose-coated PMMA composite microspheres by Pickering emulsion system

Ferulic acid loaded pickering emulsions stabilized by resistant starch nanoparticles using ultrasonication: Characterization, in vitro release and nutraceutical potential

The use of starch based nanoparticles have gained momentum in stabilizing pickering emulsions for it's numerous advantages. In present study resistant starch (RS) was isolated from lotus stem using enzymatic digestion and subjected to nanoprecipitation and ultrasonication to yield resistant starch nanoparticles (RSN). RSN of varying concentrations (2%, 10% and 20%) were used to stabilize the flax seed-oil water mixture to form pickering emulsions. The emulsions were used to nanoencapsulate ferulic acid (FA) - a well known bioactive via ultrasonication. The emulsions were lyophilized to form FA loaded lyophilized pickering emulsion (FA-LPE). The FA-LPE (2%, 10 % and 20%) were characterized using dynamic light scattering (DLS), light microscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM) and attenuated total reflectance fourier transform infra-spectroscopy (ATR-FTIR). AFM showed FA-LPE as spherical droplets embedded in the matrix with maximum peak height of 8.47 nm and maximum pit height of 1.69 nm. SEM presented FA-LPE as an irregular and continuous surface having multiple folds and holes. The ATR-FTIR spectra of all the samples displayed peaks of C = C aromatic rings of FA at 1600 cm^-1 and 1439 cm^-1, signifying successful encapsulation. In vitro release assay displayed more controlled release of FA from FA-LPE (20%). Bioactivity of FA-LPE was evaluated in terms of anti-cancer, anti-diabetic, angiotensin converting enzyme (ACE) inhibition and prevention against oxidative damage under simulated gastro-intestinal conditions (SGID). The bioactivity of FA-LPE (20%) was significantly higher than FA-LPE (2%) and FA-LPE (10%). Key findings reveal that pickering emulsions can prevent FA under harsh SGID conditions and provide an approach to facilitate the design of pickering emulsions with high stability for nutraceutical delivery in food and supplement products.

Cellulose nanofibrils-based hybrid foam generated from Pickering emulsion toward high-performance microwave absorption

The development of multifunctional microwave absorbers that worked in complex environments remains challenging. In this study, oil-in-water Pickering emulsion gelation approach was combined with freeze-drying to prepare foam-based microwave absorbers along with appealing photo-thermal conversion and thermal insulation. In hybrid foam, cellulose nanofibrils (CNF) and polylactic acid (PLA) serve as three-dimensional skeleton, where carbon nanotubes (CNT) and Fe₃O₄ nanoparticles are homogeneously incorporated, which forms a conductive network with hetero-interfaces. The optimal reflection loss value of the foam reaches -65.14 dB with a thickness of 3.0 mm. The foam also demonstrate high photo-thermal conversion performance with its surface temperature up to 97 °C after irradiation under 1 Sun for 5 min. Additionally, the foam shows superior thermal insulation comparing with the commercial polyvinyl alcohol and polyurethane foams. This study may offer a promising approach to develop ultralight and high-performance microwave absorber with great potential for multifunctional applications.

A novel self-crosslinked gel microspheres of Premna microphylla turcz leaves for the absorption of uranium

Premna microphylla turcz leaves (PMTL) is a resource-rich, biodegradable, renewable biomass. Here, a microsphere adsorbent was prepared from PMTL by a self-crosslinking method without any addition of chemical cross-linking agent, and characterized by SEM, FTIR, and XPS. The influence of preparation methods and conditions on the properties of the microspheres was studied and the self-crosslinking mechanism was analyzed. The effects of temperature, pH, contact time, uranium concentration, and adsorbent dosage on its adsorption performance toward to uranium were systematically explored. The results showed that PMTL endogenous pectin binding with endogenous Ca²⁺, Mg²⁺ and other metal ions to form an 'egg box' structure might be the mechanism of its self-crosslinking to form microspheres. The adsorption isotherms fitted well by the Freundlich model and the experimental maximum adsorption capacity of microspheres was 346.65 mg·g^-1 at pH of 5, and kinetics data correlated well with the pseudo-second order model. The adsorption mechanism might be the coordination bonding between the uranium and oxygen-containing groups (hydroxyl and carboxyl groups), and the ion exchange between the uranium and metal ions (mainly Ca²⁺ and Mg²⁺). The PMTL microspheres are promising in treating uranium-containing wastewater in a more cost-effective and environmentally friendly manner.

Environmental stability and curcumin release properties of Pickering emulsion stabilized by chitosan/gum arabic nanoparticles

In recent years, the use of food grade natural biodegradable particles as Pickering emulsion stabilizer has attracted wide attentions. In this study, chitosan/gum Arabia (CS/GA) nanoparticles were prepared and their potential use in stabilizing Pickering emulsion and delivering curcumin were evaluated. It was found that CS and GA combined mainly through electrostatic interactions, and the obtained nanoparticles were about 100 nm of size and displayed higher surface activity than chitosan nanoparticles. Fluorescence microscopy showed that the nanoparticles accumulated at the oil-water interface. The environmental stability of Pickering emulsion got improved with the increase of nanoparticle concentration, and was sensitive to the changes of pH and ionic strength, while the emulsion remained stable under all test temperatures. The Pickering emulsion stabilized by 0.75% CS/GA nanoparticles displayed higher curcumin embedding rate of 94%, and also showed improved protection on curcumin during storage and controlled release during in vitro digestion. These results confirmed that the CS/GA nanoparticle stabilized-Pickering emulsion could be used as an effective deliver system for bioactive substances.