Ordered mesoporous silica nanoparticles (MSNs) have drawn a great deal of attention in the biomedical fields because of their specific structures and unique physical chemistry properties. Combined with various functional materials or molecules, such as magnetic nanoparticles, fluorescent probes, antineoplastic drugs and targeting ligands, ordered mesoporous silica nanoparticles can be developed into the multifunctional nanomedicines in the application of diagnosis and therapy of tumor. The recent progress on synthetic methods, surface modification and application of MSNs are reviewed. First of all, the methods of synthesis in different pH medium and template removal are summarized in detail along with a brief introduction on their merits and drawbacks. Secondly, surface modification methods are described, including surface stabilization and surface functionalization. Thirdly, the application progress of targeted therapy and imaging diagnosis of MSNs loaded with imaging agents or chemotherapy drugs are also concluded. The final part outlines the challenges and perspectives.

Contents
1 Introduction
2 Preparation of MSNs
2.1 Methods of preparation in alkaline medium
2.2 Methods of preparation in acid medium
2.3 Methods of preparation in neutral medium
2.4 Methods of preparation in acid-base medium
3 Methods of removing templates
3.1 High-temperature calcination
3.2 Extraction method
3.3 Microwave digestion method
3.4 Oxidation method
3.5 Other methods
4 Surface modification and functionalization
4.1 Surface modification for stabilization
4.2 Surface modification for specific targeting
5 Application in the tumor diagnosis and therapy
5.1 Tumor diagnosis
5.2 Tumor therapy
5.3 Tumor theranostics
6 Conclusion and Outlook