Optimum iron-pyrophosphate electronic coupling to improve electrochemical water splitting and charge storage.

Tuning the electronic properties of transition metals using pyrophosphate (P2O7) ligand moieties can be a promising approach to improving the electrochemical performance of water electrolyzers and supercapacitors, although such a material's configuration is rarely exposed. Herein, we grow NiP2O7, CoP2O7, and FeP2O7 nanoparticles on conductive Ni-foam using a hydrothermal procedure. The results indicated that, among all the prepared samples, FeP2O7 exhibited outstanding oxygen evolution reaction and hydrogen evolution reaction with the least overpotential of 220 and 241 mV to draw a current density of 10 mA/cm2. Theoretical studies indicate that the optimal electronic coupling of the Fe site with pyrophosphate enhances the overall electronic properties of FeP2O7, thereby enhancing its electrochemical performance in water splitting. Further investigation of these materials found that NiP2O7 had the highest specific capacitance and remarkable cycle stability due to its high crystallinity as compared to FeP2O7, having a higher percentage composition of Ni on the Ni-foam, which allows more Ni to convert into its oxidation states and come back to its original oxidation state during supercapacitor testing. This work shows how to use pyrophosphate moieties to fabricate non-noble metal-based electrode materials to achieve good performance in electrocatalytic splitting water and supercapacitors.

Water-soluble Complex of Curcumin with Cyclodextrins: Enhanced Physical Properties For Ocular Drug Delivery.

BACKGROUND: Curcumin, a natural hydrophobic polyphenol, has been reported to have diverse pharmacological activities. Previous studies have evaluated its efficacy using both oral and transdermal dosage forms. However, two major obstacles-poor aqueous solubility and low stability-severely limited its pharmaceutical use. OBJECTIVE: The main objective of this study was to prepare curcumin eye drops that provided sustained release to allow for once daily application in retinitis pigmentosa. METHOD: To achieve our goal, curcumin was complexed with ß -cyclodextrin and hydroxypropyl-ß- cyclodextrin in two molar ratios (1:1 and 1:2) using co-solvent, co-solvent with sonication and freezedrying filtration methods. A total of 12 complexes were prepared, then characterized using differential scanning calorimetry, powder X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, solubility assessment and in vitro release studies. RESULTS: An improvement in curcumin aqueous solubility relative to pure curcumin was achieved for all 12 complexes. However, the freeze-drying filtration method was superior to all other methods because it produced highly water-soluble drug-CD complexes. Based on our stability analyses, pH 6.8 phosphate buffer containing 1% Tween 80 was selected as the release medium for in vitro release studies because curcumin exhibited high stability in this medium. Our F11 formulation provided sustained release of the drug for more than 96 h with a maximum amount released of drug (21.77±0.26 µg/ml). Our in vitro release data also showed that release of drug from curcumin-CDs inclusion complexes followed a Higuchi non-Fickian diffusion mechanism. CONCLUSION: Based on these results, F11 was formulated as eye drops, which provide a promising once daily novel topical delivery of this naturally derived phytochemical.

Conjugation of Hot-Melt Extrusion with High-Pressure Homogenization: a Novel Method of Continuously Preparing Nanocrystal Solid Dispersions.

Over the past few decades, nanocrystal formulations have evolved as promising drug delivery systems owing to their ability to enhance the bioavailability and maintain the stability of poorly water-soluble drugs. However, conventional methods of preparing nanocrystal formulations, such as spray drying and freeze drying, have some drawbacks including high cost, time and energy inefficiency, traces of residual solvent, and difficulties in continuous operation. Therefore, new techniques for the production of nanocrystal formulations are necessary. The main objective of this study was to introduce a new technique for the production of nanocrystal solid dispersions (NCSDs) by combining high-pressure homogenization (HPH) and hot-melt extrusion (HME). Efavirenz (EFZ), a Biopharmaceutics Classification System class II drug, which is used for the treatment of human immunodeficiency virus (HIV) type I, was selected as the model drug for this study. A nanosuspension (NS) was first prepared by HPH using sodium lauryl sulfate (SLS) and Kollidon® 30 as a stabilizer system. The NS was then mixed with Soluplus® in the extruder barrel, and the water was removed by evaporation. The decreased particle size and crystalline state of EFZ were confirmed by scanning electron microscopy, zeta particle size analysis, and differential scanning calorimetry. The increased dissolution rate was also determined. EFZ NCSD was found to be highly stable after storage for 6 months. In summary, the conjugation of HPH with HME technology was demonstrated to be a promising novel method for the production of NCSDs.

Engineering Photosystem I Complexes with Metal Oxide Binding Peptides for Bioelectronic Applications.

Conventional dye-sensitized solar cells comprise semiconducting anodes sensitized with complex synthetic organometallic dyes, a platinum counter electrode, and a liquid electrolyte. This work focuses on replacing synthetic dyes with a naturally occurring biological pigment-protein complex known as Photosystem I (PSI). Specifically, ZnO binding peptides (ZOBiP)-fused PSI subunits (ZOBiP-PsaD and ZOBiP-PsaE) and TiO2 binding peptides (TOBiP)-fused ferredoxin (TOBiP-Fd) have been produced recombinantly from Escherichia coli. The MOBiP-fused peptides have been characterized via western blotting, circular dichroism, MALDI-TOF, and cyclic voltammetry. ZOBiP-PSI subunits have been used to replace wild-type PsaD and PsaE, and TOBiP-Fd has been chemically cross-linked to the stromal hump of PSI. These MOBiP peptides and MOBiP-PSI complexes have been produced and incubated with various metal oxide nanoparticles, showing increased binding when compared to that of wild-type PSI complexes.

Near-infrared-absorbing gold nanopopcorns with iron oxide cluster core for magnetically amplified photothermal and photodynamic cancer therapy.

We present the synthesis and application of a new type of dual magnetic and plasmonic nanostructures for magnetic-field-guided drug delivery and combined photothermal and photodynamic cancer therapy. Near-infrared-absorbing gold nanopopcorns containing a self-assembled iron oxide cluster core were prepared via a seed-mediated growth method. The hybrid nanostructures are superparamagnetic and show great photothermal conversion efficiency (η=61%) under near-infrared irradiation. Compact and stable nanocomplexes for photothermal-photodynamic therapy were formed by coating the nanoparticles with near-infrared-absorbing photosensitizer silicon 2,3-naphthalocyannie dihydroxide and stabilization with poly(ethylene glycol) linked with 11-mercaptoundecanoic acid. The nanocomplex showed enhanced release and cellular uptake of the photosensitizer with the use of a gradient magnetic field. In vitro studies using two different cell lines showed that the dual mode photothermal and photodynamic therapy with the assistance of magnetic-field-guided drug delivery dramatically improved the therapeutic efficacy of cancer cells as compared to the combination treatment without using a magnetic field and the two treatments alone. The "three-in-one" nanocomplex has the potential to carry therapeutic agents deep into a tumor through magnetic manipulation and to completely eradicate tumors by subsequent photothermal and photodynamic therapies without systemic toxicity.

The roles of cellular nanomechanics in cancer.

The biomechanical properties of cells and tissues may be instrumental in increasing our understanding of cellular behavior and cellular manifestations of diseases such as cancer. Nanomechanical properties can offer clinical translation of therapies beyond what are currently employed. Nanomechanical properties, often measured by nanoindentation methods using atomic force microscopy, may identify morphological variations, cellular binding forces, and surface adhesion behaviors that efficiently differentiate normal cells and cancer cells. The aim of this review is to examine current research involving the general use of atomic force microscopy/nanoindentation in measuring cellular nanomechanics; various factors and instrumental conditions that influence the nanomechanical properties of cells; and implementation of nanoindentation methods to distinguish cancer cells from normal cells or tissues. Applying these fundamental nanomechanical properties to current discoveries in clinical treatment may result in greater efficiency in diagnosis, treatment, and prevention of cancer, which ultimately can change the lives of patients.

Capture and detection of cancer cells in whole blood with magnetic-optical nanoovals.

AIM: To develop a simple assay for the capture and detection of rare cancer cells in whole blood using iron oxide-gold (IO-Au) nanoparticles. MATERIALS & METHODS: IO-Au nanoovals (NOVs) were synthesized, coated with Raman tags and linked with antibodies targeting breast cancer. An integrated system was constructed for on-line magnetic cell capture and surface-enhanced Raman scattering (SERS) detection. The capabilities of IO-Au SERS NOVs to capture and detect rare cancer cells in blood were investigated in the integrated system using circulating tumor cell-mimic SK-BR-3 cells. RESULTS: SK-BR-3 cells in whole blood were magnetically captured under a flow condition using IO-Au SERS NOVs, followed by on-line SERS detection with a limit of detection of 1-2 cells/ml blood. CONCLUSION: We developed a sensitive method that can capture and detect cancer cells in whole blood with a single nanoconstruct, which is highly promising for the detection of circulating tumor cells in the clinic.

Effect of molecular weight of chitosan degraded by microwave irradiation on lyophilized scaffold for bone tissue engineering applications.

Chitosan (CTS) is biocompatible, biodegradable, and can be formed into 3D porous structures for bone tissue engineering applications. Although studies have reported on the effects of molecular weight (MW) on CTS physicochemical properties, studies evaluating CTS biological property relationships often do not account for MW that confounds interpretation of study results. The aim of this study was to evaluate the effect of MW on CTS physicochemical and biological properties. CTS materials were treated for 6, 18, and 30 min by microwave irradiation to decrease MW without affecting deacetylation (DDA). Materials were evaluated for crystallinity using X-ray diffraction, thermal degradation using differential scanning calorimetry, water content, swelling ratio, and in vitro compatibility using Saos-2. Results showed that microwave treatments did not affect DDA but decreased MW and swelling ratio by 45.78% and 36.75%, respectively, after 30 min of microwave treatment. Microwave-treated CTS showed reduced or no crystalline peaks. Initial increase in exothermic peak temperatures with short (6 min) microwave treatment times were followed by a decrease with longer (18 and 30 min) treatment times. Cell growth over 7 days on samples was proportional to MW with the number of cells being 62% higher on CTS with the highest MW (3.71 ± 0.25 × 10(5) g/mol) when compared with the lower MW CTS (2.38 ± 0.12 × 10(5) g/mol). These results demonstrate the importance of MW of CTS to both its physicochemical characteristics and biological properties, providing researchers with another tool for the modulation and optimization of CTS for different biomedical applications.