Biomimetic synthesis of CuInS2 nanoparticles: Characterization,cytotoxicity, and application in quantum dots sensitized solar cells

CuInS₂ (CIS) nanoparticles have unique chemical, toxicological and optoelectronic properties that favor their technological applications. In the present work we report a novel one step biomimetic method for the aqueous synthesis of CIS nanoparticles, that is also low cost and environmentally friendly. This biomimetic method uses only CuSO₄ and InCl₃ as precursor salts, and the biological molecule glutathione as sulfur donor and stabilizer of the nanoparticles (NPs). The reaction is performed at low temperatures, under aerobic conditions and atmospheric pressure. CIS nanoparticles produced by our biomimetic method exhibit fluorescence emission between 650 and 700 nm when excited at 500 nm. A size between 10 and 15 nm was determined by Dynamic light scattering (DLS) and corroborated by electron transmission microscopy. X-ray diffraction analysis (XRD) confirmed the crystalline structure of the CIS NPs produced. Energy Dispersive X-Ray Spectroscopy (EDX) analyses revealed the presence of Cu, In, and S in a 0.6: 1.4: 2 ratio, which has been reported for other CIS NPs in literature. No cytotoxicity of CIS NPs was observed in human OKT6/TERT2 cells and bacteria. Besides, the potential application of biomimetic CIS NPs as photosensitizers in quantum dots sensitized solar cells (QDSSCs) was confirmed. The biocompatibility, spectroscopic properties, and energy harvesting performance in solar cells of the CIS NPs produced by our biomimetic method make them suitable for their use in different biotechnological applications.     

Stabilization Of The CN35− Anion In Recoverable High-pressure Ln3O2(CN3) (Ln=La,Eu, Gd,Tb, Ho,Yb) Oxoguanidinates

A series of isostructural Ln₃O₂(CN₃) (Ln=La, Eu, Gd, Tb, Ho, Yb) oxoguanidinates was synthesized under high-pressure (25–54 GPa) high-temperature (2000–3000 K) conditions in laser-heated diamond anvil cells. The crystal structure of this novel class of compounds was determined via synchrotron single-crystal X-ray diffraction (SCXRD) as well as corroborated by X-ray absorption near edge structure (XANES) measurements and density functional theory (DFT) calculations. The Ln₃O₂(CN₃) solids are composed of the hitherto unknown CN₃⁵⁻ guanidinate anion—deprotonated guanidine. Changes in unit cell volumes and compressibility of Ln₃O₂(CN₃) (Ln=La, Eu, Gd, Tb, Ho, Yb) compounds are found to be dictated by the lanthanide contraction phenomenon. Decompression experiments show that Ln₃O₂(CN₃) compounds are recoverable to ambient conditions. The stabilization of the CN₃⁵⁻ guanidinate anion at ambient conditions provides new opportunities in inorganic and organic synthetic chemistry.     

Cyanide ion colorimetric chemosensor based on protonated merocyanine in EtOH

This Letter aimed to develop an efficient method for the determination of cyanide ion (CN⁻). A novel colorimetric chemosensor 4-[(1E)-2-(4-hydroxyphenyl)ethenyl]-1-allylpyridinium bromide (HPEAPB) was synthesized. HPEAPB displayed good selectivity toward CN⁻ over other competing anions in ethanol. A color change from yellow to red was immediately observed upon the addition of CN⁻ and the limit of detection (LOD) was 3.4 × 10⁻⁶ mol L⁻¹. The sensing mechanism was discussed by UV–vis, ¹H NMR titration, and a comparison study. Colorimetric test paper for CN⁻ was prepared by attaching HPEAPB to a chromatography paper, which could be used to detect CN⁻ in environmental samples as simply as a pH-indicator paper for pH value. The LOD of the test paper for CN⁻ was 2.0 × 10⁻⁴ mol L⁻¹. This detection method for CN⁻ has potential applications in cyanide ion containing fields by combination of rapid and real-time advantages.     

Biomimetic Cascade Polymer Nanoreactors for Starvation and Photodynamic Cancer Therapy

The selective disruption of nutritional supplements and the metabolic routes of cancer cells offer a promising opportunity for more efficient cancer therapeutics. Herein, a biomimetic cascade polymer nanoreactor (GOx/CAT-NC) was fabricated by encapsulating glucose oxidase (GOx) and catalase (CAT) in a porphyrin polymer nanocapsule for combined starvation and photodynamic anticancer therapy. Internalized by cancer cells, the GOx/CAT-NCs facilitate microenvironmental oxidation by catalyzing endogenous H₂O₂ to form O₂, thereby accelerating intracellular glucose catabolism and enhancing cytotoxic singlet oxygen (¹O₂) production with infrared irradiation. The GOx/CAT-NCs have demonstrated synergistic advantages in long-term starvation therapy and powerful photodynamic therapy (PDT) in cancer treatment, which inhibits tumor cells at more than twice the rate of starvation therapy alone. The biomimetic polymer nanoreactor will further contribute to the advancement of complementary modes of spatiotemporal control of cancer therapy.     

A Protein‐Based Encapsulation System with Calcium‐Controlled Cargo Loading and Detachment

Protein‐based encapsulation systems have a wide spectrum of applications in targeted delivery of cargo molecules and for chemical transformations in confined spaces. By engineering affinity between cargo and container proteins it has been possible to enable the efficient and specific encapsulation of target molecules. Missing in current approaches is the ability to turn off the interaction after encapsulation to enable the cargo to freely diffuse in the lumen of the container. Separation between cargo and container is desirable in drug delivery applications and in the use of capsids as catalytic nanoparticles. We describe an encapsulation system based on the hepatitis B virus capsid in which an engineered high‐affinity interaction between cargo and capsid proteins can be modulated by Ca²⁺. Cargo proteins are loaded into capsids in the presence of Ca²⁺, while ligand removal triggers unbinding inside the container. We observe that confinement leads to hindered rotation of cargo inside the capsid. Application of the designed container for catalysis was also demonstrated by encapsulation of an enzyme with β‐glucosidase activity.     

Fabrication of 105Y,Alpha 1‐Anti Trypsin Peptide Conjugated Hybrid Nanoparticles for Biological Applications

In this report, we describe the characterizations and applications of hybrid nanoparticles. These nanoparticles have been synthesized by combination of organometallic, polymerization process and functionalized with a specific peptide for targeting expressed serpin‐enzyme complex (SEC) receptor of human hepatoma HepG2 cells. By using peptide conjugated hybrid nanoparticles, the specific receptor targeting, collections of cells were successfully achieved. The cell collection results indicated that, the maximum up to 95.32% of HepG2 cell were collected. The 5‐dimethylthiazol‐2‐yl‐2,5‐diphenyltetrazolium bromide (MTT) assay of HepG2 cells incubated with these nanoparticles indicated that, the peptide conjugated hybrid nanoparticles did not possess significant cytotoxicity. The rotating magnetic field induced cell death studies indicated that, the HepG2 cell showed up to 70% of cell death was induced by hybrid nanoparticles under magnetic field. Concluding, these studies demonstrate that the hybrid nanoparticles have the capability of effective separation, imaging, targeting and killing of the human hepatoma cells.     

3-D composite electrodes for high performance PEM fuel cells composed of Pt supported on nitrogen-doped carbon nanotubes grown on carbon paper

The 3-D composite electrodes consisting of Pt nanoparticles supported on nitrogen-doped carbon nanotubes (CN_x) grown directly on carbon paper were successfully prepared. The effect of the nitrogen atom incorporation in carbon nanotubes (CNTs) on the Pt nanoparticle dispersion and catalytic activities for the oxygen reduction reaction has been investigated. Compared to regular CNTs, highly dispersed Pt nanoparticles with smaller size (2–3 nm) and higher electrochemical Pt surface area as well as higher fuel cell performance were obtained for CN_x.     

ctDNA interaction of Co-containing Keggin polyoxomolybdate and in vitro antitumor activity of free and its nano-encapsulated derivatives

Polyoxometalates (POMs) are negatively charged clusters consisting of transition metals and oxygen atoms. The antiviral and antitumor activities are the dominant activities of POMs in pharmacology and medicine. Based on Co-containing Keggin polyoxomolybdate (K₆[SiMo₁₁O₃₉Co(H₂O)].nH₂O), nanosized starch, and lipid-encapsulated derivatives (abbreviated as SiMo₁₁Co, SEP and LEP, respectively) were synthesized and characterized by FT-IR spectroscopy, ICP, TG analysis, SEM and TEM images. The results show that the SiMo₁₁Co retains its parent structure after encapsulation by starch and lipid nanoparticles. The biological activity of SiMo₁₁Co has been evaluated by investigating its binding ability to calf thymus DNA (ctDNA), using UV–Vis absorption spectroscopy, fluorescence quenching and fluorescence Scatchard plots. The obtained results of absorption titration rule out the intercalating binding mode and propose the groove or outside stacking binding for SiMo₁₁Co. These results were authenticated by fluorescence quenching experiments and scatchard plots. Absorption spectral traces reveal 10.21 % hyperchromism for SiMo₁₁Co. The value of 7.6 × 10³ M^?1 was obtained for binding constant (K_b) of SiMo₁₁Co to ctDNA. Furthermore, the in vitro antitumor activity of SiMo₁₁Co and nano-encapsulated forms was investigated using the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide (MTT) assay that was carried out on two types of human cancer cells, MCF-7 (breast cancer cells) and HEK-293 (Human Embryonic Kidney). The results represent the enhancement of cell penetration and antitumor activity of SiMo₁₁Co due to its encapsulation in starch or lipid nanoparticles. However, this observed enhancement for the lipid relative to the starch nanocapsule can be attributed to its smaller size.     

Colorimetric and fluorometric dual-modal probes for cyanide detection based on the doubly activated Michael acceptor and their bioimaging applications

In this study, we synthesized CTB and CB probes based on doubly activated Michael acceptors to selectively detect cyanide (CN⁻) anions through a one-step condensation reaction of coumarinyl acrylaldehyde with the corresponding derivatives of malonyl urea (thiourea). Through the conjugated addition of CN⁻ to the β-site of the Michael acceptor, both probes displayed colorimetric and fluorometric dual-modal responses that were highly reactive and selective. CTB generates an active fluorescent response, whereas CB displays a ratiometric fluorescent response. The fluorescent signal of the probes reached its maximum given only 1 CN⁻ equivalent and the signal change was linearly proportional to CN⁻ concentrations ranging from 0 to 5 μM with the detection limits 18 and 23 nM, respectively. The reaction rate of the probes is highly dependent on the methylene acidity of malonyl urea derivatives. Thus, the response rate of CTB to CN⁻ is 1.2-fold faster than that of CB, and the response rate of CB to CN⁻ is 1.2-fold faster than that of the previously examined CM. We then verified the highly reactive nature of the β-site of the probes through density functional reactivity theory calculations. In addition, according to proof-of-concept experiments, these probes may be applied to analyze CN⁻ contaminated water and biomimetic samples. Finally, cell cytotoxicity and bioimaging studies revealed that the probes were cell-permeable and could be used to detect CN⁻ with low cytotoxicity.     

Structural,compositional and hardness properties of hydrogenated amorphous carbon nitride thin films synthesized by dense plasma focus device

The hydrogenated amorphous carbon nitride (a‐CN_x:H) thin films were synthesized on the SS‐304 substrates using a dense plasma focus device. The a‐CN_x:H thin films were synthesized using CH₄/N₂ admixture gas and 20 focus deposition shots on substrates placed at different distances from the anode top. X‐ray photoelectron spectroscopy and Raman analysis confirmed different C–N bonding in the a‐CN_x:H thin films. A decrease in the N/C ratio as well as the sp³/sp² ratio with an increase in the substrate distance has been observed. The higher amount of C–N formation for the film synthesized at 10 cm is observed which decreases with increasing distance. The X‐ray photoelectron spectroscopy and Raman analysis affirmed the C ≡ N presence in all the thin films synthesized at different distances. The morphology of the synthesized a‐CN_x:H thin films showed nanoparticles and nanoparticle clusters formation at the surface. The hardness results showed comparatively lower hardness of the a‐CN_x:H thin films due to the presence of C ≡ N. The C–N formation with lower amount of C ≡ N and a higher N/C ratio as well as a higher sp³/sp² ratio for the films synthesized at 10 cm show reasonably higher hardness. Copyright © 2016 John Wiley & Sons, Ltd.     

Recent Advances in Cell-Based Nanotherapy for Cardiovascular Diseases

Cell-based nanotherapy holds great potential to transform diagnosis and treatment patterns for human diseases, especially for cardiovascular diseases (CVDs). Surface coating with cell membrane has become a powerful strategy for functionalization of therapeutic nanoparticles to achieve biological performances of superior biocompatibility, immune evasion, and specificity. Additionally, extracellular vesicles (EVs) play key roles in the progression of CVDs with their ability of transferring cargos to distant tissues, thus emerging as an appealing option for the diagnosis and therapy of CVDs. In this review, recent progress in cell-based nanotherapy for CVDs is summarized, and different sources of EVs and biomimetic nanoplatforms derived from natural cells are highlighted. Meanwhile, their promising biomedical applications in the diagnosis and targeted treatment of different CVDs are also provided, followed by a discussion of their potential challenges and future prospects.     

Mussel-inspired encapsulation and functionalization of individual yeast cells

The individual encapsulation of living cells has a great impact on the area of cell-based sensors and devices as well as fundamental studies in cell biology. In this work, living yeast cells were individually encapsulated with functionalizable, artificial polydopamine shells, inspired by an adhesive protein in mussels. Yeast cells maintained their viability within polydopamine, and the cell cycle was controlled by the thickness of the shells. In addition, the artificial shells aided the cell in offering much stronger resistance against foreign aggression, such as lyticase. After formation of the polydopamine shells, the shells were functionalized with streptavidin by utilizing the chemical reactivity of polydopamine, and the functionalized cells were biospecifically immobilized onto the defined surfaces. Our work suggests a biomimetic approach to the encapsulation and functionalization of individual living cells with covalently bonded, artificial shells.     

Controlled hierarchical self-assembly of networked coordination nanocapsules via the use of molecular chaperones

Supramolecular chaperones play an important role in directing the assembly of multiple protein subunits and redox-active metal ions into precise, complex and functional quaternary structures. Here we report that hydroxyl tailed C-alkylpyrogallol[4]arene ligands and redox-active Mn^II ions, with the assistance of proline chaperone molecules, can assemble into two-dimensional (2D) and/or three-dimensional (3D) networked nanocapsules. Dimensionality is controlled by coordination between the exterior of nanocapsule subunits, and endohedral functionalization within the 2D system is achieved via chaperone guest encapsulation. The tailoring of surface properties of nanocapsules via coordination chemistry is also shown as an effective method for the fine-tuning magnetic properties, and electrochemical and spectroscopic studies support that the nanocapsule is an effective homogeneous water-oxidation electrocatalyst, operating at pH 6.07 with an exceptionally low overpotential of 368 mV.

Molecular chaperones play a critical role in directing the assembly of nanocapsules that assemble into 2D or 3D coordination networks.     

Microfluidics technology for manipulation and analysis of biological cells

Analysis of the profiles and dynamics of molecular components and sub-cellular structures in living cells using microfluidic devices has become a major branch of bioanalytical chemistry during the past decades. Microfluidic systems have shown unique advantages in performing analytical functions such as controlled transportation, immobilization, and manipulation of biological molecules and cells, as well as separation, mixing, and dilution of chemical reagents, which enables the analysis of intracellular parameters and detection of cell metabolites, even on a single-cell level. This article provides an in-depth review on the applications of microfluidic devices for cell-based assays in recent years (2002–2005). Various cell manipulation methods for microfluidic applications, based on magnetic, optical, mechanical, and electrical principles, are described with selected examples of microfluidic devices for cell-based analysis. Microfluidic devices for cell treatment, including cell lysis, cell culture, and cell electroporation, are surveyed and their unique features are introduced. Special attention is devoted to a number of microfluidic devices for cell-based assays, including micro cytometer, microfluidic chemical cytometry, biochemical sensing chip, and whole cell sensing chip.     

Carbon nitride nanotubulite – densely-packed and well-aligned tubular nanostructures

Tubular carbon nitride (CN_x, x=0.01–0.32) nanoparticles were successfully synthesized by d.c. magnetron sputtering. These tubes were grown in a highly packed form perpendicularly on a sodium chloride substrate. Their number density is estimated to be 1×10⁴ per μm² and is constant over macroscopic regions. Sub-nanometer scale chemical mapping shows that the nitrogen to carbon atomic ratio is rather constant across these tubes. This successful synthesis of a nanotubulite – made of a rather compact aggregation of tubular nanoparticles – could facilitate experimental approaches to measure mechanical or electrical transport properties of such nanotubes and to open the way to variable nanotube applications.     

Cell-patterned glass spray for direct drug assay using mass spectrometry

In this work, the establishment of a glass spray mass spectrometry (GS-MS) platform for direct cell-based drug assay was described. Cell co-culture, drug-induced cell apoptosis, proliferation analysis and intracellular drug absorption measurement were performed simultaneously on this specifically designed platform. Two groups of co-cultured cells (NIH-3T3/HepG2 and HepG2/MCF-7) were cultivated and they showed high viability within 3 days. The biocompatibility of the platform facilitated the subsequent bioassays, in which, cyclophosphamide (CPA) and genistein were used as the model drugs. The distinctions of cell apoptosis and proliferation between the mono-cultured and co-cultured cells were clearly observed and well explained by in situ GS-MS measurements. A satisfactory linearity of the calibration curve between the relative MS intensity and CPA concentrations was obtained using stable isotope labeling method (y = 0.16545 + 0.0985x, R² = 0.9937). The variations in the quantity of absorbed drug were detected and the results were consistent with the concentration-dependence of cell apoptosis. All the results demonstrated that direct cell-based drug assay could be performed on the stable isotope labeling assisted GS-MS platform in a facile and quantitative manner.     

Conjugated polymer nanoparticles with aggregation induced emission characteristics for intracellular Fe3+ sensing

In this article, a novel zwitterionic conjugated polyelectrolyte containing tetraphenylethene unit was synthesized via Pd‐catalyzed Sonogashira reaction. The resulting polymer (P2), which exhibited typical aggregation‐induced emission (AIE) properties, was weakly fluorescent in dilute DMSO solution and showed bright fluorescence emissions when aggregated in DMSO/water mixtures or fabricated into conjugated polymer nanoparticles (CPNs). The nanoparticles from P2 could be prepared by reprecipitation method with an average diameter around 23 nm. Notably, the cell‐staining efficiencies of lipid‐P2 nanoparticles could be enhanced with lipid encapsulation and these nanoparticles were endocytosed via caveolae‐mediated and clathrin‐mediated endocytosis pathways. Furthermore, the lipid‐P2 nanoparticles with low cytotoxicity, high photostability and efficient cell staining ability could be employed for in vitro detection of Fe³⁺ ions in A549 cells. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 1686–1693     

Engineering of chiral nanomaterials for biomimetic catalysis

Chiral nanomaterial-based biomimetic catalysts can trigger a similar biological effect to natural catalysts and exhibit high performance in biological applications. Especially, their active center similarity and substrate selectivity promoted their superior biocatalytic activity. Here, modification of critical elements, such as size, morphology, nanocrystal facets, chiral surface and active sites, for controlling the catalytic efficiency of individual chiral nanoparticles (NPs) and chiral nanoassemblies has been demonstrated, which had a synergistic effect on overcoming the defects of pre-existing nanocatalysts. Noticeably, application of external forces (light or magnetism) has resulted in obvious enhancement in biocatalytic efficiency. Chiral nanomaterials served as preferable biomimetic nanocatalysts due to their special structural configuration and chemical constitution advantages. Furthermore, the current challenges and future research directions of the preparation of high-performance bioinspired chiral nanomaterials for biological applications are discussed.

Chiral nanomaterial-based biomimetic catalysts can trigger a similar biological effect to natural catalysts and exhibit high performance in biological applications.     

Encapsulation behaviours of nanoparticles entering two-section carbon nanotubes

Carbon nanotubes are special nanostructures due to their unique mechanical and electronic properties. One of the proposed applications is a container for drug delivery. In this paper, we consider two-section carbon nanotubes for their uses as nanocapsules to encapsulate a single atom and a C $_{60}$ fullerene. The Lennard-Jones function and the continuous approach are employed to determine the molecular interactions. Moreover, the explicit forms of their interaction energies are determined. The suction energies are utilised to determine the encapsulated conditions of both nanoparticles, where they depend on the radii of the particle and the nanocapsule. This theoretical study can be thought of as the first step to design the nanocapsule for the drug delivery devices.     

Biomimetic Method Synthesis of HgS/Polyurethane Composite Film and Its Sensing Properties to Ba2+

Polyurethane-conjugated HgS nanocrystals with tunable sizes prepared by using biomimetic method. The obtained HgS nanoparticles with good dispersibility were characterized by Fourier transform infrared. Scanning electron microscopy are used to envisage the binding of nanoparticles with functional groups. The polyurethane molecules can control nucleation and growth of HgS crystals by binding on the surface of nanocrystals to stabilize nanoparticles. Quantum confinement effect of polyurethane-conjugated HgS nanocrystals was confirmed by UV-Vis spectra. The nanoparticles exhibit a well-defined emission feature at about 291 nm. The fluorescence results reveal that the PU/HgS nanoparticles film is sensitive to Ba²⁺, and a small amount of Ba²⁺ makes the emissions increase rapidly. The emission is hardly affected by other common ions in water. The nanocomposite film is possible to become a special sensor material for Ba²⁺.