An Fe-doped CoP nanoarray behaves as a robust 3D monolithic multifunctional catalyst for electrolytic and hydrolytic hydrogen evolution with high activity. Its two-electrode electrolyzer needs a cell voltage of only 1.60 V for 10 mA cm water-splitting current. It also catalyzes effectively NaBH hydrolysis with a low activation energy of ≈39.6 kJ mol and a hydrogen generation rate of 6.06 L min g .

Replacement of precious Pt with earth-abundant electrocatalysts for the hydrogen evolution reaction (HER) holds great promise for clean energy devices, but the development of low-cost and durable HER catalysts with Pt-like activity is still a huge challenge. In this communication, we report on the development of self-standing ternary FeCoP nanowire array on carbon cloth (FeCoP/CC) as a Pt-free HER catalyst with activities being strongly related to Fe substitution ratio. Electrochemical tests show that FeCoP/CC not only possesses Pt-like activity with the need of overpotential of only 37 mV to drive 10 mA cm, outperforming all non-noble-metal HER catalysts reported to date, but demonstrates superior long-term durability in 0.5 M HSO. Density functional theory calculations further reveal that Fe substitution of Co in CoP leads to more optimal free energy of hydrogen adsorption to the catalyst surface. This study offers us a promising flexible monolithic catalyst for practical applications.

Uptake and intracellular transport of D-penicillamine coated quantum dots (DPA-QDs) of 4 nm radius by live HeLa cells have been investigated systematically by spinning disk and 4Pi confocal microscopies. Unlike larger nanoparticles, these small DPA-QDs were observed to accumulate at the plasma membrane prior to internalization, and the uptake efficiency scaled nonlinearly with the nanoparticle concentration. Both observations indicate that a critical threshold density has to be exceeded for triggering the internalization process. By using specific inhibitors, we showed that DPA-QDs were predominantly internalized by clathrin-mediated endocytosis and to a smaller extent by macropinocytosis. Clusters of DPA-QDs were found in endosomes, which were actively transported along microtubules toward the perinuclear region. Later on, a significant fraction of endocytosed DPA-QDs were found in lysosomes, while others were actively transported to the cell periphery and exocytosed with a half-life of 21 min.

It is well-known that nanomaterials are capable of entering living cells, often by utilizing the cells' endocytic mechanisms. Passive penetration of the lipid bilayer may, however, occur as an alternative process. Here we have focused on the passive transport of small nanoparticles across the plasma membranes of red blood cells, which are incapable of endocytosis. By using fluorescence microscopy, we have observed that zwitterionic quantum dots penetrate through the cell membranes so that they can be found inside the cells. The penetration-induced structural changes of the lipid bilayer were explored by surface-enhanced infrared absorption spectroscopy and electrochemistry studies of model membranes prepared on solid supports with lipid compositions identical to those of red blood cell membranes. A detailed analysis of the infrared spectra revealed a markedly enhanced flexibility of the lipid bilayers in the presence of nanoparticles. The electrochemistry data showed that the overall membrane structure remained intact; however, no persistent holes were formed in the bilayers.

Nanoparticles (NPs) are of similar size to typical cellular components and proteins, and can efficiently intrude living cells. A detailed understanding of the involved processes at the molecular level is important for developing NPs designed for selective uptake by specific cells, for example, for targeted drug delivery. In addition, this knowledge can greatly assist in the engineering of NPs that should not penetrate cells so as to avoid adverse health effects. In recent years, a wide variety of experiments have been performed to elucidate the mechanisms underlying cellular NP uptake. Here, we review some select recent studies, which are often based on fluorescence microscopy and sophisticated strategies for specific labelling of key cellular components. We address the role of the protein corona forming around NPs in biological environments, and describe recent work revealing active endocytosis mechanisms and pathways involved in their cellular uptake. Passive uptake is also discussed. The current state of knowledge is summarized, and we point to issues that still need to be addressed to further advance our understanding of cellular NP uptake.

Nanoparticles are finding a rapidly expanding range of applications in research and technology, finally entering our daily life in medical, cosmetic or food products. Their ability to invade all regions of an organism including cells and cellular organelles offers new strategies for medical diagnosis and therapy (nanomedicine), but their safe use requires a deep knowledge about their interactions with biological systems at the molecular level. Upon incorporation, nanoparticles are exposed to biological fluids from which they adsorb proteins and other biomolecules to form a 'protein corona'. These nanoparticle -protein interactions are still poorly understood and quantitative studies to characterize them remain scarce. Here we have quantitatively analysed the adsorption of human transferrin onto small (radius approx. 5 nm) polymer-coated FePt nanoparticles by using fluorescence correlation spectroscopy. Transferrin binds to the negatively charged nanoparticles with an affinity of approximately 26 mM in a cooperative fashion and forms a monolayer with a thickness of 7 nm. By using confocal fluorescence microscopy, we have observed that the uptake of FePt nanoparticles by HeLa cells is suppressed by the protein corona compared with the bare nanoparticles.

The generation of singlet oxygen ( 1 O 2 )d uring photodynamic therapyi sl imited by the precise cooperation of light, photosensitizer,a nd oxygen, and the therapeutic efficiency is restricted by the elevated glutathione (GSH) levels in cancer cells.H erein, we report that an ultrathin twodimensional metal-organic framework of Cu-TCPP nanosheets (TCPP = tetrakis(4-carboxyphenyl)porphyrin) can selectively generate 1 O 2 in at umor microenvironment. This process is based on the peroxidation of the TCPP ligand by acidic H 2 O 2 followed by reduction to peroxylr adicals under the action of the peroxidase-like nanosheets and Cu 2+ ,and their spontaneous recombination reaction by the Russell mechanism. In addition, the nanosheets can also deplete GSH. Consequently,the Cu-TCPP nanosheets can selectively destroy tumor cells with high efficiency,constituting an attractive way to overcome current limitations of photodynamic therapy.Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.

Membrane proteins are molecular machines that transport ions, solutes, or information across the cell membrane. Electrophysiological techniques have unraveled many functional aspects of ion channels but suffer from the lack of structural sensitivity. Here, we present spectroelectrochemical data on vibrational changes of membrane proteins derived from a single monolayer. ion transfer ͉ membrane potential ͉ proton translocation ͉ vibrational spectroscopy ͉ sensory rhodopsin