The investigations on the kinetics of photocatalytic inactivation of bacteriophages, lactic bacteria and lysogenic lactic bacteria have shown that the rate of bacterial inactivation is ca. 10 times less than the inactivation of bacteriophages. Titania-assisted photorelease of bacteriophages from lysogenic bacteria proves that photogenerated reactive oxygen species affect the deoxyribonucleic acid (DNA) of bacteria before their deactivation. On this basis a novel photocatalytic method of a prophage induction to the lytic cycle and detection of lysogenic bacteria is proposed.

We combine anisotropic wet etching and nanoskiving to create a novel three-dimensional (3D) nanoantenna for plasmonic nanofocusing, vertically aligned zig-zag nanogaps, constituted of nanogaps with defined angles. Instead of conventional lithography, we used the thickness of a self-assembled monolayer (SAM) to define nanogaps with high throughput, and anisotropic etching of Si V-grooves to naturally define ultra-sharp tips. Both nanogaps and sharp tips can synergistically squeeze the electro-magnetic (EM) field and excite 3D nanofocusing, enabling great potential applications in chemical sensing and plasmonic devices. The dependence of the EM field enhancement on structural features is systematically investigated and optimized. We found that the field enhancement and confinement are stronger at the tipped-nanogap compared to what standalone tips or nanogaps produce. The intensity of surface-enhanced Raman spectroscopy (SERS) recorded on the 70.5° tipped-nanogaps is 45 times higher than that recorded with linear nanogaps and 5 times higher than that recorded with tip-only nanowires, which is attributed to the integration of the tip and gap in plasmonic nanostructures. This proposed nanofabrication technique and the resulting structures equipped with a strongly enhanced EM field will promote broad applications for nanophotonics and surface-enhanced spectroscopy.

A microreactor that can confine chemical reactions exclusively in tiny vessels with the volume of ∼0.015 μm3 is introduced. Aluminum inversed hollow nanocone arrays (IHNAs) are fabricated by a simple and efficient colloidal lithography method. Ag and Au nanoparticles (NPs), as well as polypyrrole, grow exclusively in the conic cavities under light illumination. The photocatalytic effect arising from the plasmonic enhanced electric fields (E-fields) of IHNAs boosts the reactions and is in charge of the submicrometer site-selectivity. By partially inhibiting light to IHNAs, various hierarchical patterns at the macro-, micro-, and sub-microscale are obtained, inspiring a facile patterning technique by varying the light source. In addition, the Al IHNA films are transferred to flexible and curved substrates with unchanged performances, showing high flexibility for wide applications. Microreactors based on the IHNAs will contribute to the control of chemical reactions at different dimensions and offer great potentials in developing novel nanofabrication techniques.

In biological system, early detection and treatment at the same moment is highly required. For synthetic materials, it is demanding to develop materials that possess self-reporting of early damage and self-healing simultaneously. This dual function is achieved in this work by introducing an intelligent pH-responsive coatings based on poly(divinylbenzene)-graft-poly(divinylbenzene-co-methacrylic acid) (PDVB-graft-P(DVB-co-AA)) core-shell microspheres as smart components of the polymer coatings for corrosion protection. The key component, synthesized PDVB-graft-P(DVB-co-AA) core-shell microspheres are porous and pH responsive. The porosity allows for encapsulation of the corrosion inhibitor of benzotriazole and the fluorescent probe, coumarin. Both loading capacities can be up to about 15 wt%. The polymeric coatings doped with the synthesized microspheres can adapt immediately to the varied variation in pH value from the electrochemical corrosion reaction and release active molecules on demand onto the damaged cracks of the coatings on metal surfaces. It leads simultaneously to the dual functions of self-healing and self-reporting. The corrosion area can be self-reported in 6 h, while the substrate can be protected at least for 1 month in 3.5 wt% NaCl solution. These pH-responsive materials with self-reporting and self-healing dual functions are highly expected to have a bright future due to their smart, long-lasting, recyclable, and multifunctional properties.

The microtubule-kinesin system is used to form microtubule-based structures via microtubule gliding motility. On the kinesin-coated surface, the microtubules can be easily assembled into stable micro- and nanostructures like circles and microtubule bundles using the streptavidin-biotin system. Furthermore, these microtubules structures can still retain performance with kinesin motor movement in spite of different velocities. Collisions bear responsibility for the majority of events leading to circle formation. By taking advantage of biological substances, some micro- or nanostructures, which are difficult to fabricate by artificial processes, can be easily obtained.

The presence of silver on the surfaces of preformed Au nanoparticles is the key for the formation of ultrathin AuPd alloy-shells.

Hollow nanocone array (HNCA) films (cm × cm), composed of two Ag and Au nanoshells, are fabricated via a low-cost and efficient colloidal lithography technique. The relative position of the Ag and Au nanoshells can be controlled to generate various chiral asymmetries. A pronounced chiroptical response is observed in the ultraviolet-visible region with the anisotropy factor up to 10-1, which is rooted in the asymmetric current oscillations and electric field distributions. Beyond previous reports on plasmonic chiral metamaterials, the HNCA can be free-standing and further transferred to other functional and flexible substrates, such as polydimethylsiloxane (PDMS), highly curved surfaces, prepatterned films, and hydrogels, while keeping the original features. The good transferability would make HNCA more flexible in specific applications. Furthermore, the chiral HNCAs offer a series of chiral resonance cavities, which are conducive for the research of chiral sensing, confinement, chiral signal transmission, and amplification. Overall, this work provides a scalable metamaterial to tune the plasmonic chiral response, and HNCA would be a promising candidate of the components in chiral optical devices and sensors.

Polyelectrolyte multilayer (PEM) are thin polymeric films produced by alternating adsorption of positively and negatively charged polyelectrolytes (PE) on a substrate. These films are considered drug delivery agents as well as coating material for implants, due to their antibiofouling and biologically benign properties. For these reasons the film mechanical properties as well as response to mechanical stress are important measurement parameters. Especially intriguing is the correlation of the mechanical properties of PEM on macroscopic level with the structure of PEM on molecular level, which is addressed here for the first time. This study investigates PEM from PDADMA/PSS produced by spraying technique with neutron and X-ray reflectometry. Reflectometry technique provides precise information on thickness and density (i.e., electron density or scattering length density, respectively), and, this way, allows to conclude on changes in film composition. Thus, neutron and X-ray reflectometry technique is suitable to investigate the overall and the internal transformations, which PEM films might undergo upon exposure to mechanical load. During uniaxial elongation two regimes of PEM-deformation can be observed: An elastic regime at small elongations (below ca. 0.2%), which is characterized by a reversible change of film thickness, and a plastic regime with a permanent change above this limit. Both regimes have in common, that the mechanical load induces an increase of the film thickness, which is accompanied by an uptake of water from the surrounding atmosphere. The strain causes a molecular rearrangement within the PEM-structure of stratified layers, which, even in elastic regime, is permanent, although the thickness change remains reversible.

Free-standing latex films were prepared by using CNCs as templates. The structural color of the latex film shows a reversible response to water adsorption and dehydration. The maximum elongation at break of the latex film reaches 34.5%, which is ∼8 times larger than that of the best film reported so far.

AbstractA trifunctional, partially fluorinated anthracene‐substituted triptycene monomer was spread at an air/water interface into a monolayer, which was transformed into a long‐range‐ordered 2D polymer by irradiation with a standard UV lamp. The polymer was analyzed by Brewster angle microscopy, scanning tunneling microscopy measurements, and non‐contact atomic force microscopy, which confirmed the generation of a network structure with lattice parameters that are virtually identical to a structural model network based on X‐ray diffractometry of a closely related 2D polymer. The nc‐AFM images highlight the long‐range order over areas of at least 300×300 nm2. As required for a 2D polymer, the pore sizes are monodisperse, except for the regions where the network is somewhat stretched because it spans over protrusions. Together with a previous report on the nature of the cross‐links in this network, the structural information provided herein leaves no doubt that a 2D polymer has been synthesized under ambient conditions at an air/water interface.

It is well known that the activity and stability of electrocatalysts are largely dependent on their surface facets. In this work, we have successfully regulated surface facets of three-dimensional (3D) metallic Aum-n aerogels by salt-induced assembly of citrate-stabilized gold nanoparticles (Au NPs) of two different sizes and further size-dependent localized Ostwald ripening at controlled particle number ratios, where m and n represent the size of Au NPs. In addition, 3D Aum-n-Pd aerogels were further synthesized on the basis of Aum-n aerogels and also bear controlled surface facets because of the formation of ultrathin Pd layers on Aum-n aerogels. Taking the electrooxidation of small organic molecules (such as methanol and ethanol) by the resulting Aum-n and Aum-n-Pd aerogels as examples, it is found that surface facets of metallic aerogels with excellent performance can be regulated to realize preferential surface facets for methanol oxidation and ethanol oxidation, respectively. Moreover, they also indeed simultaneously bear high activity and excellent stability. Furthermore, their activities and stability are also highly dependent on the area ratio of active facets and inactive facets on their surfaces, respectively, and these ratios are varied via the mismatch of sizes of adjacent NPs. Thus, this work not only demonstrates the realization of the regulation of the surface facets of metallic aerogels by size-dependent localized Ostwald ripening but also will open up a new way to improve electrocatalytic performance of 3D metallic aerogels by surface regulation.

Polyelectrolyte multilayers assembled from hyaluronic acid (HA) and poly-l-lysine (PLL) are most widely studied showing excellent reservoir characteristics to host molecules of diverse nature; however, thick (HA/PLL)n films are often found cell repellent. By a systematic study of the adhesion and proliferation of various cells as a function of bilayer number "n" a correlation with the mechanical and chemical properties of films is developed. The following cell lines have been studied: mouse 3T3 and L929 fibroblasts, human foreskin primary fibroblasts VH-Fib, human embryonic kidney HEK-293, human bone cell line U-2-OS, Chinese hamster ovary CHO-K and mouse embryonic stem cells. All cells adhere and spread well in a narrow "cell-friendly" window identify in the range of n = 12-15. At n < 12, the film is inhomogeneous and at n > 15, the film is cell repellent for all cell lines. Cellular adhesion correlates with the mechanical properties of the films showing that softer films at higher "n" number exhibiting a significant decrease of the Young's modulus below 100 kPa are weakly adherent to cells. This trend cannot be reversed even by coating a strong cell-adhesive protein fibronectin onto the film. This indicates that mechanical cues plays a major role for cell behavior, also in respect to biochemical ones.

Structural colors originating from interaction of light with intricately arranged micro‐/nanostructures have stimulated considerable interest because of their inherent photostability and energy efficiency. In particular, noniridescent structural color with wide viewing angle has been receiving increasing attention recently. However, no method is yet available for rapid and large‐scale fabrication of full‐spectrum structural color patterns with wide viewing angles. Here, infiltration‐driven nonequilibrium assembly of colloidal particles on liquid‐permeable and particle‐excluding substrates is demonstrated to direct the particles to form amorphous colloidal arrays (ACAs) within milliseconds. The infiltration‐assisted (IFAST) colloidal assembly opens new possibilities for rapid manufacture of noniridescent structural colors of ACAs and straightforward structural color mixing. Full‐spectrum noniridescent structural colors are successfully produced by mixing primary structural colors of red, blue, and yellow using a commercial office inkjet printer. Rapid fabrication of large‐scale structural color patterns with sophisticated color combination/layout by IFAST printing is realized. The IFAST technology is versatile for developing structural color patterns with wide viewing angles, as colloidal particles, inks, and substrates are flexibly designable for diverse applications.

The dependence of the surface-enhanced Raman scattering (SERS) activity of small and large molecules on the number of polyelectrolyte monolayers covering the surface of gold nanocages (AuNCs) is investigated. The linkage of AuNCs to silica microparticles and the covering of its surface with additional polyelectrolyte layers are performed via layer-by-layer self-assembly. Either three-dimensional core-shell composite structures or hollow polyelectrolyte microspheres, obtained after the decomposition of solid templates, can be fabricated with coating thickness controlled with nanometer precision. Besides an obvious decrease of the signal intensity with increasing distance between plasmonic nanoparticle surface and Raman active molecules, there is a different signal dependence on the last layer charge for samples in water and air. The dependence of SERS signals on the number of layers also shows the difference for layers with and without thermal annealing, thus providing insight into changes in the structure of polyelectrolyte matrix. The obtained signal dependence is used to investigate the transport of low molecular weight analytes through polyelectrolyte layers and molecule interactions with polyelectrolyte chains, thus providing information about the internal layer structure that can not be obtained by direct measurements.

Colloidal lithography (CL) is a newly developing nanofabrication technique and can produce various nanostructures at low cost and large scale. The CL-based nanostructures offer great performances in plasmonics, which holds a unique capability to concentrate light into subwavelength volumes. Valuable physics effects accompanied with plasmonics, such as heat generation, optical near-field enhancement, and excitation of hot electrons have been verified to benefit chemistry reactions, leading to a new field of plasmonic nanochemistry. Starting from CL, by way of plasmonic nanostructures, toward chemistry reaction, it shows a powerful strategy to develop all these three research areas, like the silk road which has a wide profit. In this scenario, a nanoscale silk road from CL to plasmonic nanochemistry is presented. Recent plasmonic nanostructures fabricated via CL are summarized and are morphologically classified into multilayer, hierarchical, hollow, asymmetric, and other nanostructures. Mechanism and development of plasmonics nanochemistry are introduced. Application prospects of several unique CL-based structures will be expected. Finally, challenges and perspectives are offered to inspire more ingenious developments of using CL in plasmonic nanochemistry.

The current technical dilemma for gold nano particles as photothermal (PT) transducers in cancer therapy is that strong absorption in the second near-infrared (NIR) window is accompanied by strong scattering of the NIR light, which then overrides the absorption, thus significantly weakening the light-to-heat conversion efficiency. Here we successfully prepared spiky gold nanoparticles (spiky Au NPs) with a controlled number of spikes, designed according to our simulations and experimentally verified. Their overall sizes and the numbers, lengths, and widths of the spikes were judiciously adjusted to locate their surface plasmon resonance peaks in the second NIR window and also to achieve a higher absorption to-extinction ratio. As a result, the spiky Au NPs with optimal size and 6 spikes exhibited a record light-to-heat conversion efficiency (78.8%) under irradiation by 980 nm light. After surface PEGylation and conjugation with a lactoferrin (LF) ligand on the resulting spiky Au NPs, they in vivo displayed long circulation time (blood circulation half-life of similar to 300 min) and high tumor accumulation due to their larger surface-to-volume ratio. Therefore, spiky Au NPs allowed complete ablation of tumors without recurrence merely after 3 min of light irradiation at 980 nm, opening up promising prospects of cancer photothermal therapy.

Self-assembled peptide hydrogels are particularly appealing for drug delivery, tissue engineering, and antitumor therapy due to various advantageous features including excellent biocompatibility and biodegradability, defined molecular and higher organized structures, and easy availability. However, the poor mechanical and rheological properties of assembled peptide hydrogels cause difficulties in injection, thus limiting further applications. Herein, injectable peptide-based hydrogels with tunable mechanical and rheological properties were obtained by combination with a positively charged poly peptide (poly-l-lysine, PLL). Electrostatic coupling between PLL and a self-assembling dipeptide (Fmoc-FF) provides a smart switch to enable the fibrous hydrogels to be shear-thinning and self-healing, thus leading to the formation of supramolecular hydrogels with rheological properties suitable for injection. The latter can be flexibly adjusted by merely varying the concentration or the molecular weight of the polypeptide to satisfy a variety of requirements in biological applications. The hydrogels, consisting of helical nanofibers stabilized with disulfide bonds, are prepared and further injected for antitumor therapy. The results demonstrate that the helical fibrous hydrogel, without the addition of antigens, immune regulatory factors, and adjuvants, can activate T cell response and efficiently suppress tumor growth. Therefore, injectable hydrogels self-assembled by a combination of small peptides and biomacromolecules present a great potential for biomedical applications, especially for development of a new type of immuno-responsive materials toward antitumor therapy.