Red-Light-Responsive Supramolecular Valves for Photocontrolled Drug Release from Mesoporous Nanoparticles

Red-light-responsive supramolecular valves constructed by tetra-<i>ortho</i>-methoxy-substituted azobenzene (mAzo) and β-cyclodextrin (β-CD) were used to control drug release from mesoporous silica nanoparticles (MSNs). Doxorubicin (DOX) was used as a model drug and loaded into nanopores of mAzo modified MSNs. β-CD formed supramolecular valves with mAzo by host–guest interaction and closed the nanopores. Red light was able to open the supramolecular valves and induce DOX release even in deep tissue

Macro- and Microphase Separation in Block Copolymer Supramolecular Assemblies Induced by Solvent Annealing

We fabricated block copolymer (BCP) supramolecules by hydrogen bonding various carboxyl- and phenol-containing azo compounds to the poly­(4-vinylpyridine) blocks of polystyrene-<i>block</i>-poly­(4-vinylpyridine) (PS-<i>b</i>-P4VP). Thin films of the BCP supramolecules were prepared by spin-coating. Optical microscopy showed that all films of BCP supramolecules are macroscopically homogeneous immediately after spin-casting. To induce phase separation, all films were exposed to 1,4-dioxane vapor at room temperature. This solvent annealing caused always microphase separation between PS and P4VP-azo phases and sometimes also macrophase separation, i.e., azo compounds crystallized out of BCP matrices. The problem of macrophase separation in the BCP supramolecules is observed already at low concentrations of carboxyl-containing azo compounds. But phenol-containing azo compounds do not macrophase separate up to a molar ratio of azo compounds to repeat units of P4VP as large as 0.5. We conclude that self-associated hydrogen bonds of carboxylic groups and π–π stacking of azo chromophores are driving forces for macrophase separation

Visible-Light-Responsive Azopolymers with Inhibited π–π Stacking Enable Fully Reversible Photopatterning

Photoswitchable polymers are promising candidates for information storage. However, two general problems for photoswitchable polymers used in rewritable optical storage are photobleaching and inefficient switching processes in solid state. To overcome both of these obstacles, we demonstrate the synthesis of a new visible-light-switchable azobenzene-containing polymer (azopolymer) with nonstackable azo chromophores for reversible and stable information storage. The new azopolymer (PmAzo) contains ortho-methoxy-substituted azobenzene (mAzo) groups on the polymer side chains and shows reversible trans-to-cis or cis-to-trans isomerization by using distinct wavelengths of visible light. PmAzo is better suited for reversible optical storage than conventional UV-responsive azopolymers because visible light avoids the photodamage caused by UV light. Additionally, mAzo groups do not π–π stack in solid state, making photopatterning of PmAzo fully reversible. Moreover, photoinduced patterns on PmAzo can be stored for more than half a year. These properties distinguish PmAzo as a promising candidate for rewritable and stable information storage

Proteomic Characterization of Differential Abundant Proteins Accumulated between Lower and Upper Epidermises of Fleshy Scales in Onion (<i>Allium cepa</i> L.) Bulbs

<div><p>The onion (<i>Allium cepa</i> L.) is widely planted worldwide as a valuable vegetable crop. The scales of an onion bulb are a modified type of leaf. The one-layer-cell epidermis of onion scales is commonly used as a model experimental material in botany and molecular biology. The lower epidermis (LE) and upper epidermis (UE) of onion scales display obvious differences in microscopic structure, cell differentiation and pigment synthesis; however, associated proteomic differences are unclear. LE and UE can be easily sampled as single-layer-cell tissues for comparative proteomic analysis. In this study, a proteomic approach based on 2-DE and mass spectrometry (MS) was applied to compare LE and UE of fleshy scales from yellow and red onions. We identified 47 differential abundant protein spots (representing 31 unique proteins) between LE and UE in red and yellow onions. These proteins are mainly involved in pigment synthesis, stress response, and cell division. Particularly, the differentially accumulated chalcone-flavanone isomerase and flavone O-methyltransferase 1-like in LE may result in the differences in the onion scale color between red and yellow onions. Moreover, stress-related proteins abundantly accumulated in both LE and UE. In addition, the differential accumulation of UDP-arabinopyranose mutase 1-like protein and β-1,3-glucanase in the LE may be related to the different cell sizes between LE and UE of the two types of onion. The data derived from this study provides new insight into the differences in differentiation and developmental processes between onion epidermises. This study may also make a contribution to onion breeding, such as improving resistances and changing colors.</p></div

The epidermises of onion scales.

<p>(A) Red onion bulb. B, Longitudinal section of a red onion scale. (C) The lower epidermis (LE) (<i>arrow</i>). (D) The upper epidermis (UE) (<i>arrow</i>). (E-H) Light microscopy of the LE (F and H) and UE (E and G) from a yellow onion scale (E and F) and a red onion scale (G and H). The bar = 2.0 μm.</p

Protein yield and 2-DE resolved spot number of epidermises in red and yellow onion scales.

<p>Protein yield and 2-DE resolved spot number of epidermises in red and yellow onion scales.</p

Adaptive ranges for different STP settings of the PreE-to-PostE synapse in the PI circuit.

<p>A–D: Adaptive range when STD or STF (or both) are blocked off (as indicated in the title). In simulations, when blocking STD or STF (or both), we set vesicle resource (release probability) to be a constant value when input rate is fixed. The adaptive range is defined by the difference of the normalized response areas between low and high contrasts. E: Changes in the adaptive range when varying the short-term depression strength <i>U</i> in the corresponding cases from A–D.</p

Parameter values used in the numerical simulations. It is T∈{E,I}.

<p>Parameter values used in the numerical simulations. It is </p><p>T<mo>∈</mo><mo>{</mo>E,I<mo>}</mo></p>.<p></p

Neuronal spiking activities to step input.

<p>Firing rates of the <b>PreE</b> (A), <b>Inh</b> (B) and <b>PostE</b> (C) neuron populations in response to a step current input. Each dot in the background indicates a spike. Note that <b>PostE</b> shows a transient response to a step current input.</p

Pre-synaptic inhibition circuit with synaptic short-term plasticity.

<p>A: Circuit structure with an illustration of the axo-axonic connection mediating presynaptic inhibition (PI; see inset). B: Effect of short-term plasticity of the <b>PreE</b>-to-<b>PostE</b> synapses for two different input spike rates. Note that synaptic conductances show early facilitation and late depression. Pre-synaptic inhibition (PI) additionally modulates the synaptic efficacy (red versus blue line). C: The effective spike amplitude <i>p</i> within the <b>PreE</b>-to-<b>PostE</b> synapses is reduced by inhibitory activity.</p