P.P.Freitas, IEEE Magnetics Society Distinguished Lecturer INESC MN,
Lisbon
,
Portugal
and Physics Department, Instituto Superior Tecnico,
Lisbon
,
Portugal
Date: Tuesday, April 22, 2008
Time:Lecture at 7:30pm
Dinner with speaker at 6:00pm (Applebee’s in Radisson, RSVP M. Tondra 612 331-3584;
)
Location: 101 Walter Library, East Bank MPLS Campus of the
Univ.
of
Minnesota
Abstract: Integrated spintronic biochip platforms are being developed for portable, point-of-care diagnostic applications. The platforms consist of a microfluidic unit where the bioassay takes place, an arraying and detector chip consisting of target arraying current lines and integrated magnetoresistive sensors, and electronic control and readout boards. Probe biomolecules are immobilized by microspotting over sensor sites, and target biomolecules, labeled with magnetic nanoparticles are arrayed over the probe sites (magnetically assisted hybridization). After proper washing, hybridized targets are recognized by the fringe fields created by the magnetic beads, detected by the incorporated magnetoresistive sensors. Detecting geometries will be reviewed, using either out-of-plane or in-plane bead excitation, and dc or ac detection/excitation. Detection limits using spin valve and tunnel junction sensors will be presented, depending ultimately on platform electronic noise, and sensor noise characteristics. Applications to gene expression chips (Cystic Fibrosis gene mutation detection) and imuno-assay chips (anti-body-antigen recognition, e-Coli, Salmonella detection) will be presented. Spintronic biochip are also being integrated into multi -module lab-on-chip platforms including i) biomolecule extraction from biological fluids (magnetophoresis), ii) PCR modules (if required), and iii) the biomolecular recognition module. Alternative spintronic biochip geometries will also be presented ( lateral flow biosensors), where a magnetoresistive reader scans the surface of a porous strip, where labeled target biomolecules bind to immobilized probes. Finally, a brief review of other biomedical applications of magnetoresistive sensors will be given, from hybrid sensors targeted at biomedical imaging, to magnetic tweezers/sensors for DNA translocation monitoring.
Paulo Freitas is a Full Professor of Physics at the Instituto Superior Tecnico (IST) in
Lisbon
, and the Director of INESC Microsystems and Nanotechnologies. Current research topics include MRAMS, read heads for ultra high density recording, magnetoresistive biochips, and sensors for biomedical applications. He has been involved in research in the area of magnetoresistive materials and devices since he received his Ph.D in Solid State Physics from
Carnegie
Mellon
University
in 1986. His PhD thesis was on the subject of anisotropic magnetoresistance of ferromagnetic thin films and alloys. He then joined IBM Research at
Yorktown
Heights
as a post doctoral fellow working on high-TC superconductivity and transport properties of ferromagnetic thin films. In 1988 he joined INESC in
Lisbon
, where he started the Solid State Technology Group. In 1989 he became Professor of Physics at the Instituto Superior Tecnico in
Lisbon
. From 1992 to 1996, he was responsible for the start up and operation of INESC´s ASIC back-end of the line microfabrication facility. From 1996 till now, his research areas expanded to magnetoresistive read elements for magnetic data storage, magnetoresistive sensors, MRAMS, and biomedical applications including magnetoresistive biochips. He became director of INESC Microsystems and Nanotechnologies in 2001, and Full Professor of Physics at IST in 2002. Over this period, he co-authored over 200 technical papers and several chapter books. Professional activities include membership in IEEE, participation in several Publication/Program/Advisory Committees of MMM and Intermag Conferences.
Contact: Paulo Freitas, Physics Department, Instituto Superior Tecnico,
Lisbon
,
Portugal
.
