1. Tunable half coated magnetic particles and biomedical applicationsRaoul Kopelman, University of Michigan Ann Arbor, DMR 0455330 Magnetic micro and nanoparticles are increasingly widely used in biomedicine. During the past year, a new method for fabricating magnetic particles with tunable magnetic properties was developed (Sinn et al.; submitted to Applied Physics Letters) and an Asynchronous Magnetic Bead Rotation (AMBR) biosensor was utilized to measure the growth of individual E. coli bacteria in fluid (Kinnunen & Sinn et al.; submitted to Biosensors and Bioelectronics). AMBR biosensors have a wide applicability in biosensing including antigen detection (Hecht et al.; in press, Journal of Magnetism and Magnetic Materials), antimicrobial susceptibility testing (AST), and drug development. Figure 1: A 2 micrometer polystyrene particle with a magnetized Nickel coating. By varying the coating thickness, the magnetic properties, such as magnetic behavior (ferromagnetic/ superparamagnetic) and magnetic moment can be tuned. b Figure 2: (a) Magnetic field setup used for the AMBR, used to measure single bacterium growth. (b) A schematic of the rotational frequency change due to the growth of a single bacterium.

2. Tunable half coated magnetic particles and biomedical applicationsRaoul Kopelman, University of Michigan Ann Arbor, DMR 0455330 • The current turn-around-time (the isolation bacteria from clinical specimen and the device testing time) for antibiotic susceptibility testing requires over two days, which contributes to inappropriate antibiotic therapy and increased mortality, length of hospitalization, and antibiotic resistance. In response to this, we have been developing the asynchronous magnetic bead rotation (AMBR) method that enables rapid identification and antimicrobial susceptibility testing of bacteria, reducing turn-around time from days to hours. • The rising resistance of bacteria to antibiotics has been referred to by the Centers for Disease Control and Prevention as one of the world’s most pressing health problems. • Out of this, work a company was founded and in July of 2010 the company closed a Series A financing round with a Venture Capital Firm. Figure 3: An agar plate (10 mm diameter) used to culture and isolate bacteria clinically. Currently antimicrobial susceptibility testing (AST) in a hospital takes a minimum of 48 hours on average from sample collection to results. a b Figure 4: (a) An AST prototype based on the AMBR method. (b) The response of individual E. coli cells to ampicillin antibiotic.