Lianbing Zhang

Structural analysis and mapping of individual protein complexes by infrared nanospectroscopy

Mid-infrared spectroscopy is a widely used tool for material identification and secondary structure analysis in chemistry, biology and biochemistry. However, the diffraction limit prevents nanoscale protein studies. Here we introduce mapping of protein structure with 30 nm lateral resolution and sensitivity to individual protein complexes by Fourier transform infrared nanospectroscopy (nano-FTIR). We present local broadband spectra of one virus, ferritin complexes, purple membranes and insulin aggregates, which can be interpreted in terms of their α-helical and/or β-sheet structure. Applying nano-FTIR for studying insulin fibrils—a model system widely used in neurodegenerative disease research—we find clear evidence that 3-nm-thin amyloid-like fibrils contain a large amount of α-helical structure. This reveals the surprisingly high level of protein organization in the fibril’s periphery, which might explain why fibrils associate. We envision a wide application potential of nano-FTIR, including cellular receptor in vitro mapping and analysis of proteins within quaternary structures.

Reducing Stress on Cells with Apoferritin-Encapsulated Platinum Nanoparticles

The great potential for medical applications of inorganic nanoparticles in living organisms is severely restricted by the concern that nanoparticles can harmfully interact with biological systems, such as lipid membranes or cell proteins. To enable an uptake of such nanoparticles by cells without harming their membranes, platinum nanoparticles were synthesized within cavities of hollow protein nanospheres (apoferritin). In vitro, the protein-platinum nanoparticles show good catalytic efficiency and long-term stability. Subsequently the particles were tested after ferritin-receptor-mediated incorporation in human intestinal Caco-2 cells. Upon externally induced stress, for example, with hydrogen peroxide, the oxygen species in the cells decreased and the viability of the cells increased.

Preparation and Elastic Properties of Helical Nanotubes Obtained by Atomic Layer Deposition with Carbon Nanocoils as Templates

Helical nanofibers and nanotubes of inorganic materials have application potential in various fields, such as catalysis, sensors, and functional and smart systems. Currently available helical nanomaterials include coiled carbon nanotubes, carbon nanocoils, silica nanosprings, silicon carbide nanosprings, and helical transition-metal (Ti, Ta, V) oxide nanotubes. The synthesismethods for helical nanomaterials rely mainly on catalytic chemical vapor deposition (CVD) and template approaches. The template method is usually applied to the synthesis of helical oxide nanotubes because it is relatively difficult to fabricate such tubular structures directly by CVD or physical vapor deposition (PVD). Carbon nanocoils are the most successfully synthesized by CVD with good reproducibility and high yields. Previously, helical metal and oxide nanoandmicrostructures have been synthesized by electrodeposition, electroless deposition, and sol–gel methods with carbon nanocoils or microcoils as templates. However, these coating methods do not provide convenient and simple control over the thickness and uniformity of the coatings because the templates have low chemical reactivity, small diameters, and particularly large surface curvature. Moreover, certain pretreatments and suitable surfactants are required to improve the wettability and chemical reactivity of the templates. Atomic layer deposition (ALD) is a powerful growth technique for high-quality films. It utilizes the sequential exposure of reactants to substrates to achieve layer-by-layer film growth, which allows atomic-scale thickness control. Compared to traditional PVD or CVD methods, it shows outstanding advantages including precise thickness control,

Chemical Infiltration during Atomic Layer Deposition: Metalation of Porphyrins as Model Substrates

New uses for ALD: By applying standard metal oxide atomic layer deposition (ALD) to two types of porphyrins, site-specific chemical infiltration of substrate molecules is achieved: Diethylzinc can diffuse into the interior of porphyrin supramolecular structures and induce metalation of the porphyrin molecules from the vapor phase. A = Ph, p-HO(3)SC(6)H(4).

Black silicon with controllable macropore array for enhanced photoelectrochemical performance

Macroporous silicon with multiscale texture for reflection suppression and light trapping was achieved through a controllable electrochemical etching process. It was coated with TiO2 by atomic laye ...

Novel Three‐Dimensional Nanoporous Alumina as a Template for Hierarchical TiO2 Nanotube Arrays

Hierarchical micro-/nano-structures made easy. By using extremely rough, chemically etched microstructured aluminium foils, anodization in phosphoric acid under very harsh conditions, e.g., 10 wt% phosphoric acid and room temperature, can be repeatedly accomplished without suffering from breakdown. As a result, an alumina membrane with a three-dimensionally distributed nanopore structure is formed, which can be used as a general template to fabricate hierarchical micro-/nano-structures.

Receptor-Mediated Cellular Uptake of Nanoparticles: A Switchable Delivery System

8 The small size of nanoparticles and nanocages enables them to overcome various biological barriers and enter target cells, which is an attractive feature for various applications in biomedicine. For example, quantum dots, gold, and magnetic nanoparticles have been used as delivery carriers for small-interference RNA (siRNA), which has been applied for silencing specifi c genes in vitro and in vivo. [ 1–3 ]

Functionalization of Defect Sites in Graphene with RuO2 for High Capacitive Performance

Graphene is an attractive material for its physicochemical properties, but for many applications only chemically synthesized forms such as graphene oxide (GO) and reduced graphene oxide (rGO) can be produced in sufficient amounts. If considered as electrode material, the intrinsic defects of GO or rGO may have negative influence on the conductivity and electrochemical properties. Such defects are commonly oxidized sites that offer the possibility to be functionalized with other materials in order to improve performance. In this work, we demonstrate how such ultimately efficient functionalization can be achieved: namely, through controlled binding of very small amount of materials such as RuO2 to rGO by atomic layer deposition (ALD), in this way substituting the native defect sites with RuO2 defects. For the example of a supercapacitor, we show that defect functionalization results in significantly enhanced specific capacitance of the electrode and that its energy density can be stabilized even at high consumption rates.

Comparison of two endogenous delivery agents in cancer therapy: Exosomes and ferritin

Exosomes and ferritin: Two biomacromolecules from our human bodies both draw increasing interest for advanced drug delivery due to their endogenous origin and their morphology, the cage-like structures. They possess perfect naturally designed structures for loading and shielding of cargo. Their intrinsic biological functions enable a natural delivery of the load and specific targeting. More and more evidences point towards the evolution of a new era of drug delivery strategies with exosomes and ferritin, even for potential personalized therapy. This review focuses on the advantages as well as limits of exosomes and ferritin as endogenous carriers for cancer therapy. We compare their structure-specific cargo loading and their intrinsic cancer-related biological functions. Remaining challenges and promising perspectives for future development to use these two endogenous agents are discussed.

Semi-artificial and bioactive ferroxidase with nanoparticles as the active sites

Light-chain apoferritin lacks ferroxidase activity, which can be supplemented with Pt-nanoparticles. The hybrid bioinorganic nanoparticle outperforms its heavy-chain pendant in terms of ferroxidase activity, mineralization ability and inhibition resistance. Being active in a cellular environment it regulates the iron homeostasis.