Microfluidic Device for Multiple Disease Diagnostic and Monitoring Romen Rodriguez-Trujillo, Heidi Puk Hermann, Dorota Kwasny and Winnie E. Svendsen NanoBioIntegrated Systems Group, DTU-Nanotech, Denmark Julie Kirkegaard, Julia Skov and Kenneth Harlow DELTA Point of Care, Hørsholm, Denmark Filippo Iuliano, Silvia Pastorekova, Institute of Virology, Slovak Academy of Sciences, Bratislava, Slovak Republic Point of Care Technologies Conference DELTA - Hørsholm - 15 Nov 2012
The vision for this project is to develop a compact and inexpensive device for multiple disease diagnostic and monitoring in a versatile sensor platform capable of multiplex sensing. This has to be achieved in a fast, sensitive and reliable fashion with excellent selectivity. The platform needs to be user-friendly with automatic sampling and data interpretation 15 Nov 2012, Hørsholm (Danmark)
Single Particle Impedance Spectroscopy Electrical Model of a Particle with Membrane Exciting electrode R m Resistance of the medium Channel walls C m C mem Ri R m C m Capacitance of the medium R i Resistance of the cytoplasm C mem C mem Capacitance of the membrane Sensing electrode The response of the impedance of the system versus the frequency of the excitacion signal is characterisitic of the electrical parameters Rm, Cm, Ri and Cmem. 15 Nov 2012, Hørsholm (Danmark) 3
Shell model of the eukaryotic cell 15 Nov 2012, Hørsholm (Danmark)
Other Protein approach: membrane biomarker density detection Bead R i Antibodies C mem Antibodies + Proteins C mem Maximum number of sites per bead ~ 5x10 4 Diameter of a bead = 2.5 μm 1 protein each 400 nm 2 1 protein each 20 nm 15 Nov 2012, Hørsholm (Danmark) 5
Dependency with the frequency Computer simulation Impedance vs Frequency Fixed Membrane size = 10 nm Particle size changing from 1 to 5 μm Particle size Computer simulation Impedance vs Frequency Fixed particle size = 3 μm Membrane size changing from 1 to 100 nm Membrane size LF signal only size dependent HF/LF ratio depends on membrane size/properties 15 Nov 2012, Hørsholm (Danmark) 6
Strategy for Multiplexing HF/LF signal (changes in the membrane) LF signal (size) 15 Nov 2012, Hørsholm (Danmark) 7
Microfluidic flow-through impedance detection Effective multiplexing of the assay With this technique we have Compact devices Less time consuming Ability to multiplex 15 Nov 2012, Hørsholm (Danmark) 8
Measurements set-up voltage Freq. 1 Freq. 2 time 15 Nov 2012, Hørsholm (Danmark) 9
Transition time (relative) Number of beads Results - particle sizing Histogram of particle transitions amplitudes 3 and 5 micrometer polystyrene particles Signal amplitude (Volts) 3 micron particles Multi-frequency Analyser 5 micron particles Differential Impedance Measurements Signal amplitude (Volts) 15 Nov 2012, Hørsholm (Danmark)
Results - particle sizing MyOne 1um dynabeads M280 2.8um dynabeads M450 4.5um dynabeads 15 Nov 2012, Hørsholm (Danmark)
Results Proof of concept (HRP detection) Protein Coating Negative Control proportional to the type of surface coating Dynabead M280 proportional to the bead size 15 Nov 2012, Hørsholm (Danmark) 12
Results More proteins (Albumin detection) Albumin detection 62 ng/ml 15 Nov 2012, Hørsholm (Danmark)
Results Cell viability studies Human cervical cancer cells (HeLa) 100% alive cells 100% dead cells - Treated with Paclitaxel to kill 100 % of cells Flow cytometry controls - Trypan Blue staining was used to verify cell viability Experiment with 100% dead and 100% alive cells 100% living cells living cells Mixture of 50% dead cells and 50% alive cells dead cells 100% dead cells 15 Nov 2012, Hørsholm (Danmark)
Results Pathogen detection - Percentage of beads with bacteria: 52% - Average number of bacteria: 0.93 15 Nov 2012, Hørsholm (Danmark)
Conclusions Electrical Impedance Spectroscopy: label-free detection method No electrode functionalization strategy is required thus making it possible to use the same device to monitor entirely different biological scenarios Method can be used for a lot of different biological scenarios including all kind of biomolecule detection Microfluidic technology to build a compact, low-cost device Detection is very specific and sensitive: detection of small changes in the electrical properties of single particles and multiplex is possible 15 Nov 2012, Hørsholm (Danmark) 16
Acknowledgments We gratefully acknowledge: - DELTA Point of Care - The Danish Council for Science and Technology through Proof of Concept funds - EU 6 th framework Marie Curie Project CELLCHECK (Contract nr. 035854-1) - group / DTU-Nanotech 15 Nov 2012, Hørsholm (Danmark)
Thank you! Romen Rodriguez-Trujillo rrtr@nanotech.dtu.dk 15 Nov 2012, Hørsholm (Danmark) 18