Pneumatic Delivery of Untethered Micro-Surgical Tools

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dc.contributor.advisorGracias, David H.en_US
dc.contributor.committeeMemberGagnon, Zacharyen_US
dc.creatorChoi, Andrew Young-Joonen_US
dc.date.accessioned2014-12-23T05:18:52Z
dc.date.available2014-12-23T05:18:52Z
dc.date.created2014-08en_US
dc.date.issued2014-08-11en_US
dc.date.submittedAugust 2014en_US
dc.description.abstractColorectal cancer is an extremely prevalent disease within the US with high morbidity rates, which can be significantly reduced with early detection and early treatment. However, many patients are hesitant to get regular colorectal cancer screenings, and random biopsy sampling may miss small cancerous lesions. To address this issue, medical technology has improved to make procedures less invasive and yield better results with less pain and discomfort. Surgical innovations such as natural orifice translumenal endoscopic surgery (NOTES), uses natural orifices instead of incisions to gain access inside the body for surgery. Capsular endoscopes offer an ingestible alternative to colonoscopies. Untethered, thermally actuated microgrippers, which are smaller than a millimeter in diameter, have performed successful in vivo biopsies of hard to reach areas such as the bile duct, and have the potential to mass sample the gastrointestinal tract for cancer screening while minimizing tissue damage. However, it was observed that many microgrippers had difficulty attaching to gastrointestinal tissue. I have performed experiments to determine success rates of microgrippers in a random biopsy environment, assessed appropriate pressure ranges to deliver microgrippers to preserve microgripper quality during pneumatic transport, and tested pneumatically delivered microgrippers on porcine gastrointestinal tissue with good results. A pressure of 10 psi resulted in 75.51 ± 5.56% gripper viability, which we determined to be the maximum pressure for this setup due to excessive microgripper breakage beyond that pressure. Microgrippers fired onto gastrointestinal tissue in an aqueous environment with a pressure of 8 psi attached at a rate of 65.03 ± 6.87% after an external flow of 19 mL/min versus 20.44 ± 1.95% at 0 psi after flow, showing over a 3-fold increase in gripping attachment with pneumatic delivery. In all experiments, microgrippers which were fired onto tissue with an input pressure performed better than without pressure. Pneumatic delivery also showed significant improvements in vertically oriented tissue adhesion compared to previous methods of deployment. My results suggest that the introduction of pneumatics to accelerate the microgrippers to the target at higher speeds has a strong positive impact on microgripper attachment rates.en_US
dc.format.mimetypeapplication/pdfen_US
dc.identifier.urihttp://jhir.library.jhu.edu/handle/1774.2/37111
dc.languageen
dc.publisherJohns Hopkins University
dc.subjectMicrogrippersen_US
dc.subjectMicroen_US
dc.subjectNanoen_US
dc.subjectSurgeryen_US
dc.subjectBiopsyen_US
dc.subjectPneumaticen_US
dc.subjectGastrointestinalen_US
dc.subjectColonen_US
dc.subjectGastricen_US
dc.subjectAttachmenten_US
dc.subjectPressureen_US
dc.subjectAccelerateen_US
dc.subjectMinimallyen_US
dc.subjectInvasiveen_US
dc.subjectEndoscopeen_US
dc.subjectMedicalen_US
dc.subjectProcedureen_US
dc.subjectEnhanceen_US
dc.subjectAdvancementen_US
dc.subjectImprovementen_US
dc.subjectImproveen_US
dc.subjectColon canceren_US
dc.subjectCanceren_US
dc.titlePneumatic Delivery of Untethered Micro-Surgical Toolsen_US
dc.typeThesisen_US
dc.type.materialtexten_US
thesis.degree.departmentChemical and Biomolecular Engineeringen_US
thesis.degree.disciplineChemical & Biomolecular Engineeringen_US
thesis.degree.grantorJohns Hopkins Universityen_US
thesis.degree.grantorWhiting School of Engineeringen_US
thesis.degree.levelMastersen_US
thesis.degree.nameM.S.E.en_US
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