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Cellulose nanocrystals (CNC) have received much attention as a drug delivery vehicle, but their hydrophilic nature hinders hydrophobic drug loading. Ionotropic gelation using CNC and chitosan (CS) can enhance the loading/encapsulation capacity of hydrophobic compounds, improve colloidal stability, and strengthen mucoadhesion due to the cationic surface of CS. The colloidal behavior of CNC/CS nanocomposites loaded with emamectin benzoate (EMB) were elucidated by measuring the particle size, zeta potential, contact angle, and morphological structure using transmission electron microscopy. The mucoadhesive properties of the nanocomposites were evaluated by viscometric and titration method, followed by testing with zebrafish mucus. A facile and reproducible protocol to synthesize mucoadhesive CNC/CS nanocomposites that can encapsulate hydrophobic drugs is demonstrated. The optimal mass ratio for the synthesis was 1:10 (CS:CNC w/w), yielding the smallest average particle size (∼200 nm), highest zeta potentials (+40 mV), and highest drug encapsulation capacity (68.8 ± 8.7%). The steric stabilization effect of polyvinylpyrrolidone (PVP) and amphiphilic CNC stabilized the colloidal system. Importantly, the CS-coating technique enhanced the colloidal stability due to electrostatic intramolecular repulsion of the positive CS. CNC/CS nanocomposites exhibited enhanced mucoadhesive interaction with porcine mucin protein and live zebrafish mucus.

Supercapacitors (SCs) are becoming new candidates in the field of sustainable energy supply. Nevertheless, the unsatisfactory energy density due to the narrow voltage window of the supercapacitor is the main barrier to its practical application. Developing appropriate electrode materials to improve the electrochemical performance of SCs and broaden the operating voltage of supercapacitors are imperative. Herein, compatible interfacial engineering wood-derived nanostructured electrodes for aqueous asymmetric supercapacitors (AASCs) are demonstrated. The 3D carbonized wood matrix serves as a high specific surface area current collector and a porous host for the high capacitive active substance, which is composed of manganese dioxide (MnO2) nanowires and polyaniline (PANI) nanoparticles grown uniformly on the porous wall of aligned microchannels (CW@MnO2 and CW@PANI). The resulting electrochemical exchange reactive sites enable the positive electrode to deliver a high areal capacitance of 729 mF cm−2 at 1 mA cm−2 (369 F g−1 at 0.5 A g−1). The negative electrode delivers a high areal capacitance of 1721 mF cm−2 at 1 mA cm−2 (848 F g−1 at 0.5 A g−1). The areal capacitance of two electrodes is superior to most reported supercapacitor electrodes. Additionally, the assembled CW@MnO2//CW@PANI AASC achieves a desirable energy density (170.84 μWh cm−2 at a power density of 0.5 mW cm−2) because a considerable work function difference between electrodes achieved a 2 V wide voltage window. The results of this study provide a critical benchmark and optimistic incentives to adopt natural hierarchical structures to enhance the performance of new-generation energy-related systems.

Pickering emulsions are a valuable platform to efficiently encapsulate and deliver bioactive compounds in functional food systems. Research in the past decade highlights many technical and environmental advantages of emulsification using nanoparticle emulsifiers over conventional surfactants. In particular, nanoparticles are versatile and serve as a convenient platform onto which many modifications can be made to improve storage stability as well as controlled, targeted, and sustained release of bioactive compounds. However, these systems pose technical challenges alongside their benefits which can be overcome using various strategies. In this review, we discuss the recent and potential applications of Pickering emulsion systems in functional foods together with their encapsulation and delivery mechanisms.

The charge density of emulsifiers determines the thermodynamics and kinetics adsorption properties at the oil-water interface of an emulsion. This study examines the rupture resistance and stability of the crystallized dispersed phase based on the partitioning capability of cellulose nanocrystals (CNCs) with different surface charges. The charge density of CNC particles was designed through salt addition and hydrophobic modification. The measurement of dynamic interfacial tension confirmed that the reduction of negative charge of CNC particles improves their Pickering stabilizer role. We observed that the interfacial tension displayed a sigmoidal profile with increasing time. The dynamic stability of the emulsion during phase transition of the oil phase was enhanced by increasing the interfacial particle accumulation via the reduction of surface charge of CNC. The results indicated based on the surface charge adjustment, a balance between diffusion rate and kinetic barrier adsorption of particles is required to achieve optimum system stability.

Vitamin C (VC), widely used in food, pharmaceutical and cosmetic products, is susceptible to degradation, and new formulations are necessary to maintain its stability. To address this challenge, VC encapsulation was achieved via electrostatic interaction with glycidyltrimethylammonium chloride (GTMAC)-chitosan (GCh) followed by cross-linking with phosphorylated-cellulose nanocrystals (PCNC) to form VC-GCh-PCNC nanocapsules. The particle size, surface charge, degradation, encapsulation efficiency, cumulative release, free-radical scavenging assay, and antibacterial test were quantified. Additionally, a simulated human gastrointestinal environment was used to assess the efficacy of the encapsulated VC under physiological conditions. Both VC loaded, GCh-PCNC, and GCh-Sodium tripolyphosphate (TPP) nanocapsules were spherical with a diameter of 450 ​± ​8 and 428 ​± ​6 ​nm respectively. VC-GCh-PCNC displayed a higher encapsulation efficiency of 90.3 ​± ​0.42% and a sustained release over 14 days. The release profiles were fitted to the first-order and Higuchi kinetic models with R2 values greater than 0.95. VC-GCh-PCNC possessed broad-spectrum antibacterial activity with a minimum inhibition concentration (MIC) of 8–16 ​μg/mL. These results highlight that modified CNC-based nano-formulations can preserve, protect and control the release of active compounds with improved antioxidant and antibacterial properties for food and nutraceutical applications.

The authors report the synthesis of an enantiomeric block co-beta-peptide that kills methicillin-resistant Staphylococcus aureus, including biofilm and persister bacterial cells, and disperses biofilms. The copolymer displays antibacterial activity in human ex vivo and mouse in vivo infection models without toxicity.

Poly(ethylene glycol)-grafted-poly(amido amine) (PEGylated-PAMAM) dendrimers have attracted increasing amounts of attention because of their improved stability, toxicity, and better particle drug leakage property. The complexation of α-cyclodextrin (α-CD) with grafted PEG segments on the surface of PAMAM dendrimers was elucidated by light scattering and titration calorimetry. At pH 10, complexation between α-CD and PEGylated-PAMAM occurred once α-CD was titrated into the PAMAM solution. We observed for the first time a unique phenomenon at pH 2, where no binding took place until a critical α-CD concentration (C*) of ∼8.0 mM was reached. The size of the nanostructures increased from 6.7 to 57.6 nm when the α-CD concentration was increased from 0.5 to 15 mM at pH 2. The zeta potential of PEGylated-PAMAM at pH 2 was +6.7 mV. Thus, the dendrimers possessed positive charges attributed to the protonation of primary amine groups on PAMAM chains that impart electrostatic repulsive forces to the system. The morphology of the complex is expected to be different at two different pH values (2 and 10) because the former produces a clear solution and the latter forms a turbid solution with white precipitates. [ABSTRACT FROM AUTHOR]