Development of thermo-responsive magnetic nanoparticles for Cryptosporidium oocyst recovery

A protozoan parasite Cryptosporidium is shed in the feces of humans and other animals. Cryptosporidium oocysts have a robust wall, which is resistant to many environmental factors as well as to normal disinfection processes... [ view full abstract ]

A protozoan parasite Cryptosporidium is shed in the feces of humans and other animals. Cryptosporidium oocysts have a robust wall, which is resistant to many environmental factors as well as to normal disinfection processes for tap water. We have developed a process called surfactant extraction treatment (SET) that can extract nucleic acids from the oocyst using only surfactants in order to simplify the method for oocysts detection (Sekikawa, Wat Sci Tech:Water Suppl, 17(1), 161-168, 2017).  

Thermo-responsive magnetic nanoparticles (MNPs) show a property of reversible phase transition between dispersion and aggregation depending on temperature. In this study, we tried to develop thermo-responsive MNPs for recovering oocysts from water samples in order to apply the MNPs to the SET method. Thermo-responsive MNPs for recovering the oocysts were made from a combination of thermo-responsive MNPs (JNC Corporation）and Cryptosporidium parvum monoclonal antibody (Crypy-a-Glo biotin, Waterborne) (Fig. 1). Oocysts recovered by the MNPs were supplied to a SET tube directly. Subsequently, 18S rDNA extracted by SET was amplified using a quantitative PCR assay. As a result, we were able to recover oocysts using the MNPs and detected DNA in the oocysts.