Coronavirus outbreaks have recently necessitated rapid virus recovery and vaccine developments. Magnetic beads are essential components to recover virus in an immunoprecipitation process. Pure iron particles with a diameter of 1 µm can be used as core materials of high-performance magnetic beads.Thus, the development of effective and green synthesis method of Fe nanoparticles is important. However, Fe nanoparticles were synthesized only in acidic solution by using strong reducing reagent, such as NaBH4, while it cannot be achieved in the basic solution since iron hydroxide, which is easily formed in this condition, cannot be reduced into metals. However, former is not suitable for commercial synthesis method because of its intense reducing process. Thus, the reducing rout of Fe species under basic condition should be developed.Here, until now, we tried to synthesis the various metal/alloy nanoparticles, such as Pd20Te7 nanoparticles and uniform Cu-In (CI) alloy nanoparticles, by utilizing the restrict metallic complexes controlling method in an aqueous solution under room temperature. In this method, reduction potential of the metal species can be controlled under the room temperature, consequently metal/alloy nanomaterials with uniform and well crystallized structure can be successfully synthesized.So, in this study, we proposed the synthesis method of iron particles under basic conditions, and morphological conditions control of iron particles by utilizing the “gel-sol” method using gel networks, which is a safe and simple approach to suppress the chain crystallization.Calculation results indicated that Fe complex can be restricted into one species as the function of pH, complexing reagent species and/also concentration. For example, Fe complex can be restricted into single complex in the basic condition (for example 8<pH<11).By using this homogeneous condition, metal Fe nanoparticles were successfully synthesized. The addition of gel networks into the synthesis system can effectively suppress the chain crystallization of iron particles. Furthermore, in order to obtain iron particles with organic-free surface, we proposed a novel method to decompose and remove the gel networks.Other results will present in our presentation. This work was supported by JSPS KAKENHI Grant Number 21H03628 and DOWA holdings.[1] H. Takahashi et.,al, Applied Catalysis A: General 392 (2011) 80–85