Nano diamond is a kind of artificial diamond material with very small particle size and spherical or nearly spherical shape. The particle size is 0.5~10nm, with an average of 4~5nm, and most of the particle size distribution is 2~8nm. 

The synthesis methods of nano diamond particles mainly include hydrostatic synthesis, diamond single crystal grinding and detonation, and all of them have been used in industrial production.  In addition, diamond film or coating can be divided into micron level and nano level according to particle size. Nano diamond film is a diamond film composed of nano grain grown by CVD method. This film is smooth, compact and non-porous, which is a key material for the preparation of biosensors and biomedical instruments.  

Nanoscale diamond not only has the inherent excellent characteristics of diamond, but also has the unique properties of nano materials.  Nano diamond has been developed as early as more than 30 years ago, but in the past,its application is limited to the field of abrasives such as polycrystalline, polishing agents. With further understanding of nano diamond properties, nanometer diamond has been in the lubricating oil, metal coating, magnetic recording system, medical and other fields began to get application, and application fields are expanded.  

Nano diamond polishing paste and suspension can be used for semiconductor silicon wafers, computer heads, radio, medical, machinery manufacturing - cutting tools, gemstones and other industries, precision polishing of materials, can achieve mirror effect on any solid, surface roughness Ra up to 2~8nm.  

The application of Nano diamond in lubricating oil, grease and coolant is mainly used in mechanical industry, metal processing, engine manufacturing, shipbuilding, aviation, transportation and so on.  At present, the average energy efficiency of machinery in the world  is only about 30%. According to German logue FuEr professor calculated, the world produces energy 1/3 to 1/2 of the loss on the friction and wear, and the British Jiao Si professor pointed out that 30% to 40% of the world's energy consumption on the friction loss. From the perspective of equipment lubrication, dry friction can be harmful,  it is mainly manifested in the loss of energy and wear of parts. Nano diamond in lubricating oil can prolong the working life of engine and transmission device, save fuel oil, reduce friction torque by 20~40%, and reduce friction surface wear by 30~40%.  1000 kg of oil consumption nano diamond 0.1~0.2 kg, but nano diamond application in lubricating oil must solve its stable suspension problem, the company has solved this problem.  

The application of nano-diamond in the medical field, its unique physical and chemical properties, diversity of surface groups, low toxicity, biocompatibility and fluorescence characteristics of low photobleaching, has attracted the attention of researchers to its value in the research and application of biomedical field, and has made breakthrough progress in the recent decades.  A variety of functional groups can be designed and introduced on the surface of nano-diamond. With the improvement of the modification and treatment methods of these groups, its application value can be better reflected.  Nowadays, nano-diamond has been used in biomedical fields such as drug delivery, gene therapy, biological labeling, biological imaging, cancer diagnosis and treatment.  They have no carcinogenic or mutagenic properties and are not toxic.  However, they show very high activity against pathogenic viruses, microorganisms and bacteria. Due to their high adsorption capacity and other unique characteristics, they will be strongly absorbed. They are super-active adsorbents.  In biology, reducing the mobility of active substances is a means to dramatically strengthen the effect of medicinal reagents, and the application of nano-diamond induces the normalization of blood pressure.  In addition, nano-diamond is also effective when the gastrointestinal system is affected, which is the best means to prevent burns, unlike skin diseases, and visceral poisoning.  

Nano diamond is the isotropy of carbon element, which is pure carbon itself. It has the advantages of stable chemical properties and no reaction in strong acid and alkali environment. It is non-toxic and has no side effects, so it has been widely used in medical research.  On the one hand, nano-diamond is used as a biological carrier in medical research to make antibody drugs directly enter the human body with nano-diamond and effectively improve the treatment effect of diseases.  On the other hand, nano-diamond surface structure has a strong binding force with DNA, which can be applied to wear resistant coatings on artificial bones and joints. Cobalt, chromium and nickel are mostly used in traditional medical implants, but some patients are allergic to or reject these metals.  Diamond coating has good biocompatibility and will not cause rejection reaction of human body.  And diamond has antibacterial properties, can inhibit the breeding of bacteria.  In addition, compared with traditional metal polymer implants, nano-diamond coated artificial joints wear less and produce little debris, effectively extending the service life of artificial bones and joints and saving medical costs.  

Research suggests that the combination of nanotechnology and medicine could radically change the way cancer is treated.  Nano materials will become "precision guided missiles", with special surface modification nano diamonds killing about 70% of skin cancer cells and no toxic side effects on normal cells.  It has the advantage of being chemically inert, fluorescent but non-toxic, and can be used for cell labeling and biological imaging.  Moreover, nano diamond particles contain a large number of oxygen-containing functional groups on the surface. Nano diamond can be used as the carrier of glucose oxidase to make a blood glucose sensor with excellent performance.  In view of the excellent compatibility of nano diamond to organisms, both France and Germany use nano diamond as a new medium for human interaction, which is expected to achieve important breakthroughs in the field of artificial retinal implantation and magnetic resonance imaging.  

It is the comprehensive technical characteristics that make it has been applied in the field of traditional and new technologies, and preliminary achievements, has the characteristics of the spherical and spherical nanometer diamond grains and make the friction surface form the ball bearing effect, and showed good lubricity, thereby avoiding to the occurrence of the phenomenon, and for some of the major failure as a result of contact fatigue or high temperature wear artifacts,  The composite coating of nano diamond metal has obvious advantages.

---EDITOR: Yun Li/Doris Hu

---POST: Doris Hu