Nanogel Multienzyme Mimics Synthesized by Biocatalytic ATRP and Metal Coordination for Bioresponsive Fluorescence Imaging.

The design of enzyme mimics from stable and nonprotein systems is especially attractive for applications in highly specific cancer diagnosis and treatment, and it has become an emerging field in recent years. Herein, metal crosslinked polymeric nanogels (MPGs) were prepared using FeII ion coordinated biocompatible acryloyl-lysine polymer brushes obtained from an enzyme-catalyzed atomic transfer radical polymerization (ATRPase) method. The monoatomic and highly dispersed Fe ions in the MPGs serve as efficient crosslinkers of the gel network, and also as active centers of multienzyme mimics of superoxide dismutase (SOD) and peroxidase (POD). The catalytic activities were compared to those of conventional Fe-based nanozymes. Studies on both cells and animals verify that efficient reactive oxygen species (ROS) responsive biofluorescence imaging can be successfully realized using the MPGs.

Dip-In Photoresist for Photoinhibited Two-Photon Lithography to Realize High-Precision Direct Laser Writing on Wafer.

For decades, photoinhibited two-photon lithography (PI-TPL) has been continually developed and applied into versatile nanofabrication. However, ultrahigh precision fabrication on wafer by PI-TPL remains challenging, due to the lack of a refractive index (n) matched photoresist (Rim-P) with effective photoinhibition capacity for dip-in mode. In this paper, various Rim-P are developed and then screened for their applications in PI-TPL. In addition, different lithography methods (in terms of oil-mode and dip-in mode) are analyzed by use of optical simulations combined with experiments. Remarkably, one type of Rim-P (n = 1.518) shows effective photoinhibition capacity, which represents an outstanding breakthrough in the field of PI-TPL. In contrast to photoresist with an unsuitable refractive index, optical aberrations are almost completely eliminated in the dip-in mode by using the Rim-P. Consequently, features with a minimum critical dimension as small as 39 nm are successfully achieved on wafer by dip-in PI-TPL, which paves the way for subdiffraction silicon-based chip manufacturing by PI-TPL. Moreover, through a combination of the Rim-P and dip-in mode, the ability to achieve tall and high-precision three-dimensional nanostructures is no longer problematic.