RF Detection of Analytes


Executive Summary


Due to public health concerns since the 1920’s, the U.S. dairy industry is federally required to be monitored and treated for bacterial contamination. Most municipalities mandate pasteurization to reduce the number of viable pathogens likely to cause disease. Pre- and post-pasteurized milk is often tested for contamination via an indirect enzymatic test (alkaline phosphatase activity). Similarly, dairy farmers use another indirect assay called the California Mastitis Test that qualitatively shows excessive presence of somatic cells (white blood cell leukocytes), which are associated with a bacterial infection. Neither of these tests directly measure bacterial counts, however. MSU researchers have addressed this concern by developing a new wireless RF reader technology that offers a fast, direct method of bacterial detection from liquids such as milk, juice, or a natural water source.


Description of Technology


This MSU technology is a passive wireless interdigitated sensor tag for pathogen detection, capable of detecting, for example, bacterial levels within a complex liquid. The apparatus consists of a 3D-printed acrylic smart vial, a RFID-compatible sensor tag, and a wireless RF reader. Detection can be done in real time (in-the-field) without the need for long incubations or the need to send the samples to a remote laboratory. The detection process proceeds first with a wash mixture comprising of dextrin-coated gold nanoparticles and subsequent placement into a disposable acrylic smart vial. Coated bacteria interact with the biosensor strip and a wireless RF reader provides the readout.


Key Benefits

  • Faster detection of bacterial counts (results in 1 hour vs 48 hour for plate incubations).
  • Detection of a bacteria load as low as log 5 CFU/ml
  • Non-contact, non-invasive (wireless) sensing approach
  • Compatible with RFID infrastructure
  • Chemical components stable and offers long storage life
  • Usable on complex liquids (milk, oil, juice, natural water source, etc.)



  • Quality control for food supply chain, including dairy farmers & milk distributors, juice manufacturing, and meat-packaging
  • Field-enabled water quality control (bacterial contamination water supply & runoff)
  • Potential for specific bacterial targeting using antibody or DNA-based alterations to design


Patent Status: 


Patent Pending.


Licensing Rights Available


Full licensing rights available


Inventors: Premjeet Chahal, Evangelyn Alocilja, Saranraj Karuppuswami, Leann Matta


Tech ID: TEC2018-0032


Patent Information:

For Information, Contact:

Raymond Devito
Technology Manager
Michigan State University