1. School of Biomedical Engineering, Science & Health Systems WWW.BIOMED.DREXEL.EDU V 1.0 SD [030814] NANOSCALE MICROENCAPSULATION RESEARCH Development and Characterization of a NanoScale Contrast Agent PROGRAM OVERVIEWPROGRAM OVERVIEW Faculty: Margaret Wheatley, PhD, Drexel University. E-mail: wheatley@coe.drexel.edu Objective: To test the feasibility of creating a surfactant-stabilized nano-bubble with favorable acoustic properties to act as an ultrasound contrast agent that targets tumors. Nano Pros and Cons Cons US reflection proportional to r 6 Resonance f o ~ 6500/d kHz 1  6.5 MHz but 0.1  65 MHz More prone to removal by RES Pros Current agents are micro size, good to stay in vasculature, for nano, extravazation and pooling in tumor Angiogenesis - formation of new vasculature from existing blood vessels and is enhanced in tumor growth Tumor blood vessels prone to exhibit leakiness –Due to open pores at certain interendothelial junctions Pore sizes range from 380 to 780 nm –Allows for macromolecular transvascular transport May be beneficial to contrast imaging and chemotherapeutic drug delivery Gerwins et al. Critical Reviews in Oncology/Hematology 34: 185-194, 2000 Tumor Vasculature

2. School of Biomedical Engineering, Science & Health Systems WWW.BIOMED.DREXEL.EDU V 1.0 SD [030814] PROJECTOVERVIEWPROJECTOVERVIEW DEVELOPMENT AND CHARACTERIZATION OF A NANOSCALE CONTRAST AGENT Endothelial cell Cell junction gap Ultrasound wave Nanoscale contrast agent Optical Microscope 1000x 1 division = 10mm ESEM Image, Bar = 2mm Top = 1.55mm Lower = 1.33mm Concept of NanoScale Contrast Agent The Contrast Agent ST68 Faculty: Margaret Wheatley, PhD, Drexel University. E-mail: wheatley@coe.drexel.edu

3. School of Biomedical Engineering, Science & Health Systems WWW.BIOMED.DREXEL.EDU V 1.0 SD [030814] DEVELOPMENT AND CHARACTERIZATION OF A NANOSCALE CONTRAST AGENT Dr. Allen’s Microscope Ranged from 1 to 10 mm Wesco Verta 7000, Scion Imaging Bar = 10mm Upper mean=4.90+/-0.69 mm, n=12 Lower mean=2.05+/-0.32 mm, n=1 Horiba Size Distribution Mean Size 1.24+0.2 mm, n = 15 ESEM Image, Bar = 2mm Top = 1.55mm Lower = 1.33mm ST68 Optical Size Measurements Horiba and ESEM Size Results PROJECTOVERVIEWPROJECTOVERVIEW Faculty: Margaret Wheatley, PhD, Drexel University. E-mail: wheatley@coe.drexel.edu

4. School of Biomedical Engineering, Science & Health Systems WWW.BIOMED.DREXEL.EDU V 1.0 SD [030814] DEVELOPMENT AND CHARACTERIZATION OF A NANOSCALE CONTRAST AGENT 1-300 (min/ RPM ) 3-300 (min/ RPM ) 3-500 (min/ RPM ) Size (  m) 0.690.450.49 Enhancement (dB)2725.523 ST68-N Effect of Centrifugation PROJECTOVERVIEWPROJECTOVERVIEW Faculty: Margaret Wheatley, PhD, Drexel University. E-mail: wheatley@coe.drexel.edu

5. School of Biomedical Engineering, Science & Health Systems WWW.BIOMED.DREXEL.EDU V 1.0 SD [030814] DEVELOPMENT AND CHARACTERIZATION OF A NANOSCALE CONTRAST AGENT Panametrics 5072PR LeCroy 9350A PowerMac 7500/132 GPIB Interface Transducers 2.25, 5, 7.5, 10, 15 MHz Stirrer Tank Sample container with acoustic window Pulse-Echo Amplified Signal In Vitro Setup PROJECTOVERVIEWPROJECTOVERVIEW Faculty: Margaret Wheatley, PhD, Drexel University. E-mail: wheatley@coe.drexel.edu

6. School of Biomedical Engineering, Science & Health Systems WWW.BIOMED.DREXEL.EDU V 1.0 SD [030814] DEVELOPMENT AND CHARACTERIZATION OF A NANOSCALE CONTRAST AGENT Model: Force Balance with Centrifugal Acceleration PROJECTOVERVIEWPROJECTOVERVIEW Faculty: Margaret Wheatley, PhD, Drexel University. E-mail: wheatley@coe.drexel.edu

7. School of Biomedical Engineering, Science & Health Systems WWW.BIOMED.DREXEL.EDU V 1.0 SD [030814] DEVELOPMENT AND CHARACTERIZATION OF A NANOSCALE CONTRAST AGENT Conclusions: We have demonstrated that a nano sized bubble population can be produced by separation of a mixed population of bubbles, through careful choice of separation parameters. It will be very interesting to see if extravazation of this agent through leaky tumor vasculature can be achieved, most likely with the aid of ultrasonic energy creating pressure waves and microstreaming. Pre InjectonPost Injection 0.1 ml/kg 2.8 kg New Zealand White Rabbit PRF=700 MI=0.33 1min 29sec 12.5 MHz Transducer Pre Injecton Post Injection 0.1 ml/kg 2.8 kg New Zealand White Rabbit PRF=700 MI=0.26 1min 58sec 7-4 Transducer In Vivo Results PIHI PROJECTOVERVIEWPROJECTOVERVIEW Faculty: Margaret Wheatley, PhD, Drexel University. E-mail: wheatley@coe.drexel.edu