They found that the blood glucose level of diabetic rats decreased when treated with AgNPs for 14 days and 21 days without significant acute toxicity

They found that the blood glucose level of diabetic rats decreased when treated with AgNPs for 14 days and 21 days without significant acute toxicity. smaller than AgNPs, silver ?ngstrom (?, 1 ? = 0.1 nm) particles (Ag?Ps), which exhibit better biological activity and lower toxicity compared with AgNPs. Finally, we conclude the current difficulties and point out the future development direction of AgNPs. and may contribute to the development of bio-friendly and safe brokers. In recent years, a considerable amount of researches involving AgNPs show enough evidence of encouraging medical applications of silver nanomaterials. However, the potential toxicities of AgNPs to mammals and cell lines alert us to be cautious about its utilization. This reminds us to carry out more researches to obtain safe, bio-friendly brokers containing AgNPs. This short article provides a review of the applications of AgNPs and potential toxicology from an objective stance with insights toward understanding deep implications for medicine. Synthesis of AgNPs The synthesis methods of nanoparticles (NPs) are mainly divided into two processes: top-down and bottom-up (Physique ?Physique11). The top-down approach refers to the formation of metal NPs from bulk materials using numerous physical causes to synthesis NPs, such as mechanical energy used in ball milling, crushing and grinding; electrical energy used in the electrical arc-discharge method and laser ablation method; and thermal energy used in vapor condensation method 51. These methods can obtain NPs between 10 and 100 nm in size. The BMS-906024 top-down approach, mainly the physical method, may acquire real nanoparticles without chemical additives. NPs synthesized by physical method may exhibit uniform particle size distribution and high purity. Though the physical approach does not contain chemical reagents which may harm human and environment, it brings a great challenge to prevent agglomeration due to absence of stabilizer or capping brokers. Furthermore, these methods need complex gear and external energy in the process. The bottom-up approach Fzd10 involves the construction of complex clusters to obtain NPs from molecular components by employing nucleation and growth processes 51, 52. The commonly used bottom-up approaches include chemical synthesis and biological synthesis, both can obtain NPs by reducing the precursor salt 52. The chemical synthesis can be coupled with alternate energies, such as photochemical 53, electrochemical 54, microwave-assisted 55 and sonochemical methods 12. Though the chemical method is usually carried out to quickly obtain numerous designs of NPs, the use of harmful chemical additives may limit the medical applications of NPs. To overcome the shortcomings of the chemical method, the biological method has been regarded as an alternative option. The biological method usually relies on macromolecular substances in bacteria, fungi, and algae 16, such as exopolysaccharide, cellulose, and enzymes, and organic components in plant extracts such as enzymes, alcohol, flavonoids, alkaloids, quinines, terpenoids, phenolic BMS-906024 compounds 16, 56-59. Biological synthesis is an economical, environmentally friendly, simple and reliable approach, but the components on the surface of nanoparticles must be properly considered in the application. Based on these two approaches, frequently used methods for synthesizing AgNPs, including physical, chemical and biological methods are discussed herein. Open in a separate window Physique 1 Silver nanoparticles synthesis: top-down approach and bottom-up approach, i.e. physical synthesis method, chemical and biological synthesis methods, separately. The top-down approach refers to the formation of metal nanoparticles from bulk materials, while the bottom-up approach refers to the growth of complex clusters and obtained nanoparticles from molecular components. Physical Method The physical synthesis of AgNPs entails mechanical processes and vapor-based processes. Energies are used to reduce particle size, including mechanical energy (ball milling method) 60, electrical energy (electrical arc-discharge method) 61, light energy (laser ablation method) 62, and thermal energy (physical vapor deposition) 6 (Table ?Table11). During the ball milling progress, high-speed collisions between rigid balls, such as ceramics, BMS-906024 flint pebbles, and stainless steels, can produce localized high pressures, which grind the metal into very fine powders 60. The electrical arc-discharge method can obtain NPs via arc discharge device under direct current (DC) power 63. The device uses the powder reagent layer as the anode and the electrodes are immersed in dielectric liquids such as hydrocarbons, liquid inert gas, and deionized water. Laser ablation method refers to the ablation of a metal plate by a high-power laser, the metal target absorbs the laser beam energy and photoions, followed by nucleation and growth of metal particles during the plasma plume cooling process.