The Super resolution microscopy systems of core facilities, zhejiang university school of medicine were introduced in 2015 and opened up to the majority of teachers and students. It has received enthusiastic attention from teachers and students. Through the platform technicians and the research team member's constant exploration, the stochastic optical reconstruction microscopy(STORM )technology in the international demonstrated collagen mineralization for the first time, provides an advanced and reliable technical methods for cross-cutting scientific research.

On January 8, 2018, the Department of Chemistry of Zhejiang University, a Cheung Kong Scholar Chair Professor of Ruikang Tang group at the "Advanced Materials" (IF: 19.79) reported a titling "Citrate Improves Collagen Mineralization via Interface Wetting: A Physicochemical Understanding of Biomineralization Control " research paper. This paper demonstrated that small biomolecules citrate can promote collagen biomineralization via reducing interface energy. Moreover, Tang et al. elucidated the citrate play very important role in bones or teeth formation. It is well known that the intrafibrillar mineralization of collagen is vital for its mechanical properties and is key to biological generations of hard tissues, such as bone and dentin. However, how to verify that collagen mineralization is intrafibrillar is a technical challenge. Through communication between the imaging facility technical staff and professor Tang, Tang group firstly use Super resolution STORM (stochastic optical reconstruction microscopy) technique to determine mineralized collagen (Fig1 i-k). They obtained a three-dimensional super resolution pixel picture of single mineralized collagen by z-stepping technology displaying different level and high-resolution three-dimensional rendering, which the resolution up to 20 nm at lateral and up to 50 nm at axial. This is the first time in the world that using super resolution STROM technology to prove the intrafibrillar mineralization, which has a very important role in promoting the research of collagen mineralization.

Fig 1. Mineralization of the collagen fibrils in the absence and presence of citrate pretreatment

Stochastic optical reconstruction storm technology is based on the optical fluorescence molecular and calculation methods, generally samples were labeled with chemiluminescent probes with high luminescence intensity, high-intensity laser fluorescence groups are used to quickly switch the state of light and dark, through the ground state - excited state - Steady state - the ground state of the cycle, repeated recording fluorescent points, and finally after a delicate calculation, fitted to a high-resolution image. single molecular orientation principle and 3D storm fitting principle are shown in fig 2, 3.

Fig 2. single molecular orientation principle     Fig3. 3D storm fitting principle

At present facility for microscopic imaging also has many high-resolution microscopes, the information is as follows:

Core facilities, Zhejiang university school of medicine Warmly welcome the majority of teachers and students to make an appointment to use high-resolution microscope, platform technicians and teachers and students will discuss various experimental techniques and methods to help PI and students to obtain high-quality research results. (booking website :www.cfzsm.zju.edu.cn)