Radioactivity resistance evaluation of polymeric materials for application in radiopharmaceutical production at microscale

Microfluidic technologies are gaining increasing importance due to their capability of manipulating fluids at the microscale that should allow to synthesize many products with surprisingly high yields and short reaction times. In the lab-on-chip field researchers have developed microfluidic apparatuses to provide special equipments for producing positron emission tomography (PET) radiopharmaceuticals in a quicker, safer, and more reliable way compared to traditional vessel-based approaches. In this paper, we have selected a number of polymeric materials, such as polydimethylsiloxane (PDMS), SU-8, and Teflon-like coatings deposited on PDMS or hard substrates, to be used for the fabrication of micro apparatuses for radiosynthesis. Their radioactivity resistance was investigated employing different setups and the results analyzed by atomic force microscopy (AFM), optical microscopy, and Fourier transform infrared spectroscopy (FT-IR). To evaluate undesired absorption effects in the investigated materials, the fluoride radioactive trapping inside microchannel was measured through autoradiography. We found out that polymeric materials such as SU-8 and Teflon coated on hard materials seem very appealing for fabricating microreactors for radiochemistry.