1. Tested our device with creamed honey and water. Variables included: -Number of beads -Bead Type -Quantity of honey and water Measured absorbance using spectrophotometer. Results indicate Zn beads contaminate solution. Absorbance values for stainless steel beads stabilized at a faster rate than for glass beads. Abstract Design Criteria References Acknowledgments Dhaval Desai 1, Nathan Kleinhans 1, Lee Linstroth 1, Malini Soundarrajan 1 Advisor: Professor Naomi Chesler, Ph.D. 1, Client: Dr. Darin Y. Furgeson, Ph.D. 2 1 Department of Biomedical Engineering, 2 School of Pharmacy Future Work Problem Definition Background – Cancer has affected many people worldwide. Current treatments for cancer include chemotherapy, radiation therapy, hormonal therapy, and immunotherapy [1]. These treatments are invasive and harm normal tissue. ELPs may serve as a less invasive gene and drug delivery agent because they are non-immunogenic. They are also hydrophobic and undergo inverse state transition, thereby aggregating above a certain transition temperature due to hydrophobic collapse [4]. Motivation – Since the solublization process in the harvesting of ELP is time consuming and labor intensive, a device is desired to convert the ELP aggregate into a soluble form. This device should require minimal manual labor and should solublize ELP rapidly. Harvesting ELP Final Design Prototype Testing Efficiently resolublize ELP harvested from 2 liters of bacteria (1 liter of bacteria yields approximately 180 mg of ELP). Accommodate test tube (10.3 cm x 2.8 cm) Automated and require minimal manual labor. The final ELP solution should be uniform in concentration with complete resolublization. The device should operate at room temperature. Elastin-like polypeptides (ELPs) are genetically engineered biopolymers that serve as potential non-viral gene or drug delivery agents for cancer treatments. ELP is purified from bacteria resulting in a viscous ELP pellet. We modified an existing rock tumbler design to develop a device to efficiently resolublize ELP aggregate in Phosphate Buffered Saline (PBS) solution. To ensure that our device is efficient and produces a solution with uniform concentration we tested it with both ELP and creamed honey. Further modifications to our design may allow for the resolublization of larger quantities of ELP. Modify the design to accommodate multiple test tubes. -Enlarge drum size. -Add holes to test tube holding apparatus. Further testing with ELP and different sized stainless steel beads The final design for our device is composed of a rotating drum that contains an apparatus that holds a test tube at an angle. Stainless steel beads are placed into the test tube to aid in the resolublization process. Figure 6: Absorbance data from testing prototype with creamed honey. 1. American Cancer Society. 02/06/2006. Copyright 2006. Retrieved on 02/17/2006 from 2. Betre H, Setton LA, Meyer DE, Chilkoti A. Characterization for genetically engineered elastin-like polypeptide for cartilaginous tissue repair. Biomacromolecules. 2002 Sep-Oct, 3(5): 910-6. 3. Chilkoti A, Dreher MR, Meyer DE, Design of thermally responsive recombinant polypeptide carriers for targeted drug delivery. Adv. Drug Deliv Rev. 2002 Oct 18; 54(8): 1093-111. Review 4. Chilkoti A, Dreher MR, Meyer DE, Raucher D. Targeted drug delivery by thermally responsive polymers. Adv Drug Deliv. Rev. 2002 Sep 13; 54(5): 613-30. Review Thanks to Darin Furgeson, Ph.D., and members of his lab for their help in testing our device. We would also like to thank our advisor, Naomi Chesler, Ph.D., for her continued support and encouragement. Figure 1: Current procedure used to isolate ELP from E. coli bacteria. The ELP gene is inserted into a plasmid and then transformed into E. coli cells. Once transcribed, ELP is separated out through cell lysis and several temperature controlled centrifugations. The ELP pellet, shown in red, is extremely viscous and must be resolublized. Test Tube Apparatus High density polyethylene Supported by three peripheral bolts Angled hole -Allows beads maximum contact with pellet Figure 2: Prototype fully assembled. Designed from a model rock tumbler. Figure 3: Collapsed view of drum. Figure 5: Drum components. From bottom up: drum, test tube apparatus, primary cover, secondary cover, guiding nut. Test tube is pictured over top left of secondary cover. Figure 4: Test tube and holding apparatus in drum. Stainless Steel Beads Solid to prevent flaking of outer coats Will not corrode Autoclavable Device Lortone rock tumbler Drum rotates on its side