Sol–gel condensation of tetraethoxysilane in the presence of designed self‐assembled β‐sheet peptide fibril templates, followed by template extraction, yields hollow silica nanotubes. The nanotubes are hundreds of nanometers long and possess a central pore of ∼ 3.5 nm, determined by the fibril template diameter. The effects of synthesis conditions have been investigated and the resultant silica materials characterized by various techniques.Silica nanostructures with various morphologies have been produced previously using supramolecular organic assemblies as templates. Hollow nano‐ or microtubes, which may have applications in separations, catalysis, nano‐optics, and ‐electronics have been of particular interest. Peptide‐based templates are especially interesting because of their relevance to biological silica microstructure formation. The new fibrillar peptide templates described here have the advantages of prescribed diameter, twist pitch, and handedness, which should impart chirality on the resulting silica nanotubes, providing control of the internal surface architecture by appropriate peptide design.

Cyclic molecular frameworks, especially the benzannulated medium-sized and macrocyclic ring (BMR) systems, constitute an integral component of a large number of biologically significant natural or synthetic molecules. Many of these BMR compounds are either approved as drugs or have reached the late developmental stages in clinical trials. Such cyclic systems have been shown to possess great potential, especially in the discovery of new anticancer leads. Efforts from synthetic chemists have led to the development of elegant new strategies for the construction of BMR scaffolds of medicinalimportance. This review intends to highlight the importance of benzannulated medium-sized and macrocyclic rings (BMRs) and the strategies developed over the years for their synthesis.

Photoacoustic imaging has been a focus of research for clinical applications owing to its ability for deep visualization with optical absorption contrast. However, there are various technical challenges remaining for this technique to find its place in clinics. One of the challenges is the occurrence of reflection artifacts. The reflection artifacts may lead to image misinterpretation. Here we propose a new method using multiple wavelengths for identifying and removing the reflection artifacts. By imaging the sample with multiple wavelengths, the spectral response of the features in the photoacoustic image is obtained. We assume that the spectral response of the reflection artifact is better correlated with the proper image feature of its corresponding absorber than with other features in the image. Based on this, the reflection artifacts can be identified and removed. Here, we experimentally demonstrated the potential of this method for real-time identification and correction of reflection artifacts in photoacoustic images in phantoms as well as in vivo using a handheld photoacoustic imaging probe.

No abstract