Does PDMS really interact with [18F]fluoride? Applications in microfluidic reactors for 18F-radiopharmaceuticals

Abstract

Microfluidic devices used to synthesize radiopharmaceuticals for positron emission tomography (PET) are of increasing interest for the rapid preparation of on-demand doses, especially in medical centers that do not have a cyclotron. Polydimethylsiloxane (PDMS) is an inexpensive, easily available material used for the manufacturing of microfluidic devices. The literature often refers the interaction of this material with [18F]fluoride. Many authors discard PDMS as a suitable material because of these interactions, while others suggest the use of a thin fluoropolymer coating to reduce the adsorption of [18F]fluoride. The objective of this work was to evaluate the retention of [18F]fluoride within a PDMS reaction chamber without further treatment, under heating and vacuum in a range of activities that would allow to obtain enough product for two or three human doses of a radiopharmaceutical. Under these conditions, which are commonly used in radiosynthesis with [18F]fluoride, we found that [18F]fluoride was almost non-adsorbed into PDMS, making PDMS suitable for 18-F radiochemistry on single-use lab-on-chip devices, even uncoated.