Guilherme Pinheiro recently joined the Biomaterials Group as a Visiting Scientist sponsored by the “NIST-SIM Engagement Opportunity” program, working with Nancy Lin and Sandra da Silva. Guilherme is a researcher at the National Institute of Metrology, Quality and Technology (INMETRO, Brazil), where he works on implementing and validating culture- and DNA-based methods for the identification and enumeration of relevant bacterial species in water and food. At NIST, he is seeking to advance microbial metrology capabilities by combining digital polymerase chain reaction (dPCR), known for its ability to absolutely quantify DNA copy number, with PMA (propidium monoazide) in order to selectively amplify DNA from viable bacterial cells. This project will help advance the underlying measurements needed to support development and characterization of microbial whole cell reference materials characterized for both total and viable cell count. In addition, the implementation of this measurement capability at INMETRO will allow the provision of faster and more reliable testing services to support food industry, public safety programs and to overcome commercial technical barriers.