Cordelia Selomulya

Enzymatic hydrolysis of rice dreg protein: Effects of enzyme type on the functional properties and antioxidant activities of recovered proteins

The effects of various proteases on the formation and characteristics of rice dreg protein hydrolysates (RDPHs) were investigated. Enzymatic hydrolysis of often under-utilised rice dreg protein (RDP) with different enzymes studied here was found to significantly improve protein content and solubility. RDPHs prepared by alkaline protease showed better protein recovery, producing higher protein content with much smaller peptides, while hydrolysates generated by Protamex showed the highest antioxidant activities with more than 80% solubility over a wide pH range. The results indicated that the type of protease greatly influenced the molecular weight and amino acid residue composition of RDPH. The enzyme type also determined the functional properties and antioxidant activity of the recovered proteins. It was found that an optimum allocation of alkaline protease in addition to the Neutrase enzyme could be an appropriate strategy to produce RDPH with desirable functionalities, antioxidant properties, and low salt content.

Amorphous TiO2 Shells: A Vital Elastic Buffering Layer on Silicon Nanoparticles for High‐Performance and Safe Lithium Storage

Smart surface coatings of silicon (Si) nanoparticles are shown to be good examples for dramatically improving the cyclability of lithium-ion batteries. Most coating materials, however, face significant challenges, including a low initial Coulombic efficiency, tedious processing, and safety assessment. In this study, a facile sol-gel strategy is demonstrated to synthesize commercial Si nanoparticles encapsulated by amorphous titanium oxide (TiO2 ), with core-shell structures, which show greatly superior electrochemical performance and high-safety lithium storage. The amorphous TiO2 shell (≈3 nm) shows elastic behavior during lithium discharging and charging processes, maintaining high structural integrity. Interestingly, it is found that the amorphous TiO2 shells offer superior buffering properties compared to crystalline TiO2 layers for unprecedented cycling stability. Moreover, accelerating rate calorimetry testing reveals that the TiO2 -encapsulated Si nanoparticles are safer than conventional carbon-coated Si-based anodes.

A General “Surface-Locking” Approach toward Fast Assembly and Processing of Large-Sized, Ordered, Mesoporous Carbon Microspheres†

Drying to meet you: Using microfluidic jet spray drying technology in conjunction with the evaporation-induced self-assembly strategy gives fast assembly (2 s) of mesoporous carbon microspheres. The key feature of the drying is the formation of a rigid silica crust which locks the particle size and shape.

Oriented Mesoporous Nanopyramids as Versatile Plasmon-Enhanced Interfaces

We developed a facile interfacial oriented growth and self-assembly process to fabricate three-dimensional (3D) aligned mesoporous iron oxide nanopyramid arrays (NPAs). The unique NPAs possess a 3D mesostructure with multiple features, including high surface area (~175 m(2)/g), large pore size (~20 nm), excellent flexibility (bent over 150 times), and scalability at the foot scale for practical applications. More importantly, these NPAs structures enable versatile enhancement of localized surface plasmon resonance and photoelectrochemical conversion. The integration of plasmonic gold with 3D NPAs remarkably improves the performance of photoelectrochemical conversion, leading to ~6- and 83-fold increases of the photocurrent under simulated solar and visible-light illumination, respectively. The fabrication and investigation of NPAs provide a new paradigm for preparing unconventional mesoporous oriented thin films and further suggest a new strategy for designing plasmonic metal/semiconductor systems for effective solar energy harvesting.

Direct Superassemblies of Freestanding Metal–Carbon Frameworks Featuring Reversible Crystalline-Phase Transformation for Electrochemical Sodium Storage

High-power sodium-ion batteries (SIBs) with long-term cycling attract increasing attention for large-scale energy storage. However, traditional SIBs toward practical applications still suffer from low rate capability and poor cycle induced by pulverization and amorphorization of anodes at high rate (over 5 C) during the fast ion insertion/extraction process. The present work demonstrates a robust strategy for a variety of (Sb-C, Bi-C, Sn-C, Ge-C, Sb-Bi-C) freestanding metal-carbon framework thin films via a space-confined superassembly (SCSA) strategy. The sodium-ion battery employing the Sb-C framework exhibits an unprecedented performance with a high specific capacity of 246 mAh g-1, long life cycle (5000 cycles), and superb capacity retention (almost 100%) at a high rate of 7.5 C (3.51A g-1). Further investigation indicates that the unique framework structure enables unusual reversible crystalline-phase transformation, guaranteeing the fast and long-cyclability sodium storage. This study may open an avenue to developing long-cycle-life and high-power SIBs for practical energy applications.

The effects of engineered nanoparticles on pulmonary immune homeostasis.

Abstract Engineered nanoparticles (ENP), which could be composed of inorganic metals, metal oxides, metalloids, organic biodegradable and inorganic biocompatible polymers, are being used as carriers for vaccine and drug delivery. There is also increasing interest in their application as delivery agents for the treatment of a variety of lung diseases. Although many studies have shown ENP can be effectively and safely used to enhance the delivery of drugs and vaccines in the periphery, there is concern that some ENP could promote inflammation, with unknown consequences for lung immune homeostasis. In this study, we review research on the effects of ENP on lung immunity, focusing on recent studies using diverse animal models of human lung disease. We summarize how the inflammatory and immune response to ENP is influenced by the diverse biophysical and chemical characteristics of the particles including composition, size and mode of delivery. We further discuss newly described unexpected beneficial properties of ENP administered into the lung, where biocompatible polystyrene or silver nanoparticles can by themselves decrease susceptibility to allergic airways inflammation. Increasing our understanding of the differential effects of diverse types of nanoparticles on pulmonary immune homeostasis, particularly previously underappreciated beneficial outcomes, supports rational ENP translation into novel therapeutics for prevention and/or treatment of inflammatory lung disorders.

Design of magnetic polyplexes taken up efficiently by dendritic cell for enhanced DNA vaccine delivery.

Dendritic cells (DC) targeting vaccines require high efficiency for uptake, followed by DC activation and maturation. We used magnetic vectors comprising polyethylenimine (PEI)-coated superparamagnetic iron oxide nanoparticles, with hyaluronic acid (HA) of different molecular weights (<10 and 900 kDa) to reduce cytotoxicity and to facilitate endocytosis of particles into DCs via specific surface receptors. DNA encoding Plasmodium yoelii merozoite surface protein 1–19 and a plasmid encoding yellow fluorescent gene were added to the magnetic complexes with various % charge ratios of HA: PEI. The presence of magnetic fields significantly enhanced DC transfection and maturation. Vectors containing a high-molecular-weight HA with 100% charge ratio of HA: PEI yielded a better transfection efficiency than others. This phenomenon was attributed to their longer molecular chains and higher mucoadhesive properties aiding DNA condensation and stability. Insights gained should improve the design of more effective DNA vaccine delivery systems.

On designing stable magnetic vectors as carriers for malaria DNA vaccine.

Superparamagnetic iron oxide nanoparticles (SPIONs) can be used as therapeutic and diagnostic agents due to their unique magnetic characteristics, provided that they are stable in physiological conditions. Here, the assembly of different magnetic vector configurations comprising SPIONs, polyethylenimine (PEI), and hyaluronic acid (HA), acting as carriers for malaria DNA vaccine encoding Plasmodium yoelii merozoite surface protein MSP1-19 (VR1020-PyMSP1-19), and their stability in different cell media were investigated. The order of assembly affected vector size, surface charge, stability, and ability to bind and release DNA. Generally, all vectors showed relatively small size of less than 200 nm in water, whereas higher degree of aggregation was observed immediately after transferring to high-ionic strength media such as 150 mM NaCl buffer and RPMI 1640 culture media (Roswell Park Memorial Institute medium). However, the pre-addition of HA to DNA effectively reduced the extent of aggregation in serum-free RPMI 1640 with sizes of almost all complexes remaining below 90 nm, particularly at HA:PEI charge ratio of 100%. The presence of fetal bovine serum (FBS) in RPMI 1640 culture media further converted the surface charge of vectors from positive to negative, decreasing the size to smaller than 50 nm. Partial disassembly of some vectors was observed in water, in RPMI, and in RPMI supplemented with 10% FBS after incubation for 1h, but not in NaCl buffer, indicating that incubation of complexes in NaCl buffer prior to transfection may limit the intracellular release of plasmid DNA. DNase sensitivity assay showed that plasmid DNA vaccine encoding the PyMSP1-19 in all configurations preserved their structural integrity without damage, even after DNase I treatment for 30 min. This study demonstrated that structurally well-defined magnetic gene carriers could be designed to improve malaria DNA vaccine delivery systems, particularly for in vivo applications.

Particle size dependence of heating power in MgFe2O4 nanoparticles for hyperthermia therapy application

Magnetic nanoparticles with narrow size distributions have successfully been synthesized by an ultrasonic assisted co-precipitation method. The effects of particle size on magnetic properties, heat generation by AC fields, and the cell cytotoxicity were investigated for MgFe2O4 nanoparticles with mean diameters varying from 7 ± 0.5 nm to 29 ± 1 nm. The critical size for superparamagnetic to ferrimagnetic transition (DS→F) of MgFe2O4 was determined to be about 13 ± 0.5 nm at 300 K. The specific absorption rate (SAR) of MgFe2O4 nanoparticles was strongly size dependent; it showed a maximum value of 19 W/g when the particle size was 10 ± 0.5 nm at which the Neel and Brownian relaxations are the major cause of heating. The SAR value was suppressed dramatically by 46% with increasing particle size from 10 ± 0.5 nm to 13 ± 0.5 nm, where Neel relaxation slows down and SAR results primarily from Brownian relaxation loss. A further reduction in SAR value was evident when the size was increased from 13 ± 0.5 nm to ...

Formation of monodisperse mesoporous silica microparticles via spray-drying.

In this work, a protocol to synthesize monodisperse mesoporous silica microparticles via a unique microfluidic jet spray-drying route is reported for the first time. The microparticles demonstrated highly ordered hexagonal mesostructures with surface areas ranging from ~900 up to 1500 m(2)/g and pore volumes from ~0.6 to 0.8 cm(3)/g. The particle size could be easily controlled from ~50 to 100 μm from the same diameter nozzle via changing the initial solute content, or changing the drying temperature. The ratio of the surfactant (CTAB) and silica (TEOS), and the amount of water in the precursor were found to affect the degree of ordering of mesopores by promoting either the self-assembly of the surfactant-silica micelles or the condensation of the silica as two competing processes in evaporation induced self-assembly. The drying rate and the curvature of particles also affected the self-assembly of the mesostructure. The particle mesostructure is not influenced by the inlet drying temperature in the range of 92-160 °C, with even a relatively low temperature of 92 °C producing highly ordered mesoporous microparticles. The spray-drying derived mesoporous silica microparticles, while of larger sizes and more rapidly synthesized, showed a comparable performance with the conventional mesoporous silica MCM-41 in controlled release of a dye, Rhodamine B, indicating that these spray dried microparticles could be used for the immobilisation and controlled release of small molecules.