ABSTRACT
Three-dimensional (3D) printing technology is a rapid prototyping technology for designing 3D models with special shape and complex internal structure via computer-aided/controlled drawing and preparing. This technology displays the characteristics of flexible processing, rapid shaping, low operating cost and high reliability. 3D printing technology may provide new strategies and approaches for the generation of a variety of new drug delivery systems, which makes its application in pharmaceutics attractive. This review briefly introduces the process and feature of 3D printing technology in preparation field and mainly introduces the research progress in the design and engineering of related preparations in the aspects of rate-controlled drug release, time-controlled drug release and targeted drug release. The prospects and challenges of 3D printing technology in the formulation engineering are analyzed.
ABSTRACT
While transmission electron microscopy and scanning tunneling microscopy reveal atomic structures of point defect and grain boundary in monolayer transition-metal dichalcogenides (TMDs), information on point defect distribution in macroscale is still not available. Herein, we visualize the point defect distribution of monolayer TMDs using dark-field optical microscopy. This was realized by anchoring silver nanoparticles on defect sites of MoS2 under light illumination. The optical images clearly revealed that the point defect distribution varies with light power and exposure time. The number of silver nanoparticles increased initially and reached a plateau in response to light power or exposure time. The size of silver nanoparticles was a few hundred nanometers in the plateau region as observed using optical microscopy. The measured defect density in macroscale was â¼2 × 10(10) cm(-2), slightly lower than the observed value (4 × 10(11) cm(-2)) from scanning tunneling microscopy.