**AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** FOOD ALLERGIES ARE CONSIDERED ONE OF THE MOST IMPORTANT PUBLIC HEALTH ISSUES BECAUSE MILLIONS OF PEOPLE AROUND THE WORLD SUFFER FROM MILD TO SEVERE REACTIONS WHEN ENCOUNTERING FOOD ALLERGENS SUCH AS MILK, PEANUT, AND SHELLFISH. ANOTHER PROBLEM OF SIGNIFICANT CONCERN IS THE EMERGING CONTAMINANTS THAT ARE INCREASINGLY DETECTED IN WELL, MUNICIPAL, AND SURFACE WATERS. THEY INCLUDE PHARMACEUTICALS, PESTICIDES, HERBICIDES, AND OTHER CHEMICALS WHICH MAY AFFECT HUMAN AND ANIMAL HEALTH. THEREFORE, ALLERGENS AND EMERGING CONTAMINANTS ARE AMONG THE ITEMS (ANALYTES) THAT ARE IMPORTANT TO ACCURATELY DETECT WITH SENSORS. ONE OF THE MOST COMMON METHODS FOR DETECTING ALLERGENS, AS WELL AS WATER CONTAMINANTS, IS ENZYME-LINKED IMMUNOSORBENT ASSAY (ELISA). EVEN THOUGH ELISA IS A RELIABLE AND SENSITIVE, METHOD FOR RUNNING MANY TESTS AT ONCE, IT IS TIME CONSUMING, NEEDS TO BE PERFORMED IN A LAB BY A SKILLED TECHNICIAN, AND RATHER EXPENSIVE. ON THE OTHER HAND, HOME TESTS ARE PORTABLE, FAST, AND INEXPENSIVE. HOWEVER, THEY OFTEN LACK SENSITIVITY AND ARE TYPICALLY DESIGNED FOR ONLY ONE TYPE OF ANALYTE. THERE IS A GROWING NEED FOR SENSORS THAT HAVE THE BEST ATTRIBUTES OF BOTH TYPES OF TESTS: PORTABLE, INEXPENSIVE, AND HIGHLY SENSITIVE DETECTION OF MULTIPLE ANALYTES.THIS PROJECT PROPOSES USING NATURAL AND RENEWABLE RESOURCES CALLED CELLULOSE NANOCRYSTALS (CNC) FOR THE DEVELOPMENT OF SENSORS THAT FULFILL THIS NEED. THE SENSORS WILL BE BASED ON MEASURING MASS CHANGES RESULTING FROM ANALYTE ABSORPTION. THIS WILL BE ACHIEVED BY DEVELOPING SCHEMES FOR IMMOBILIZING DIFFERENT ANTIBODIES ON CNC THAT CAUSE SPECIFIC ANALYTES TO BIND TO THE CNC SURFACE. INITIALLY, SENSING WILL BE PERFORMED USING A STANDARD MASS-BASED METHOD CALLED QUARTZ CRYSTAL MICROBALANCE WITH DISSIPATION (QCM-D). THESE RESULTS WILL BE USED TO VALIDATE THE PORTABLE CNC BASED CANTILEVER SENSORS, A TYPE OF MICROELECTROMECHANICAL SYSTEM, THAT ARE THE FOCUS OF THIS RESEARCH. MODEL FOOD ALLERGENS AND EMERGING CONTAMINANTS WILL BE USED TOEXPLORE THE NEW SENSORS' CAPABILITIES. THE RESULTS OF THIS RESEARCH WILL ENABLE NEW UNDERSTANDING OF HOW CNC, A TINY MATERIAL FOUND IN ALL PLANTS AND TREES, CAN BE USED TO CREATE NOVEL BIOSENSORS. IF SUCCESSFUL, THIS RESEARCH CAN LEAD TO PORTABLE, SENSITIVE, LOW COST SENSORS FOR A RANGE OF APPLICATIONS. THIS WILL BE PARTICULARLY IMPACTFUL FOR PEOPLE WITH FOOD ALLERGIES, AND THOSE IN RURAL COMMUNITIES WHO NEED FREQUENT, LOW-COST TESTING OF WELL AND SURFACE WATERS.