Three-dimensional nanoscale vortex line visualization and chiral nanostructure fabrication of tightly focused multi-vortex beams via direct laser writing

Optical singularity is pivotal in nature and has attracted wide interest from many disciplines nowadays,including optical communication,quantum optics,and biomedical imaging.Visualizing vortex lines formed by phase singularities and fabricating chiral nanostructures using the evolution of vortex lines are of great significance.In this paper,we introduce a promising method based on two-photon polymerization direct laser writing(2PP-DLW)to record the morphology of vortex lines generated by tightly focused multi-vortex beams(MVBs)at the nanoscale.Due to Gouy phase,the singularities of the MVBs rotate around the optical axis and move towards each other when approaching the focal plane.The propagation dynamics of vortex lines are recorded by 2PP-DLW,which explicitly exhibits the evolution of the phase singularities.Additionally,the MVBs are employed to fabricate stable three-dimensional chiral nanostructures due to the spiral-forward property of the vortex line.Because of the obvious chiral features of the manufactured nanostructures,a strong vortical dichroism is observed when excited by the light carrying orbital angular momentum.A number of applications can be envisioned with these chiral nanostructures,such as optical sensing,chiral separation,and information storage.

Construction of self-assembled nanogel as mulitenzyme mimics for bioresponsive tandem-catalysis imaging

The self-assembled phospholipid-or cytosolassociated multienzyme complexes constitute necessary components of the foundation of life.As a proof of concept,metalcoordinated supramolecular nanogels (MCSGs) have been designed,with the self-assembly of di-lysine coordinated iron(Fe(Lys)_(2))-functionalized peptide gelators on the interface by an in situ amidation-induced protonation process.The monoatomic and highly dispersed active centers of Fe(Lys)_(2) offered the nanogel mimics with excellent reaction rates due to the high density and nano compartmental structure similar to the natural matrix-associated multienzyme complex.SiO_(2)@MCSGs show both superoxide dismutase (SOD) activity and peroxidase (POD) activity,and the higher activities compared with the activity of free Fe(Lys);molecules can be detected.After loading the substrate 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulphonate)(ABTS),SiO_(2)@MCSGs;can responsively convert O^(-)_(2) in the tumor microenvironment into H_(2)O_(2) intermediates and then tandem catalyze the oxidization of ABTS for contrast photoacoustic (PA) imaging of tumor by the SOD-POD mimic activity,showing their great potential as the efficient enzymatic agents for pathological theranostics.