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3D Swimming Micro Drone with Dosage Controllable Drug Release

Liu, Fang-Wei (2021) 3D Swimming Micro Drone with Dosage Controllable Drug Release. Doctoral Dissertation, University of Pittsburgh. (Unpublished)

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Mobile micro-robots that can navigate in liquid environment have drawn a great interest due to their possibility in serving as a maneuverable in vivo cargo for medical uses, for instance, biosensing, bioimaging, microsurgery, or drug delivery. This dissertation describes the development and investigation of an untethered, bubble-powered micro drone that can navigate in3-D spaces equipped with a controllable drug releasing function in three parts: (1) design, fabrication, and testing of the 3-D micro drone, (2) development of the drug releasing mechanism and its integration with the micro drone, and (3) examination of the ability of drone in the tissue-like environments including analyses of the acoustic signal transmission through soft materials. First, propulsion of the micro drone was achieved by microstreaming generated by acoustically oscillating bubbles trapped inside one-end-open micro tubes. A two-photon polymerization 3-D printer was utilized to create a complex 3-D structure of the drone that has at least three different groups of micro tubes aligned in three different directions for three independent thrusts. By carefully selecting the lengths of the micro tubes and arranging them into different directions, the microstreaming flow can navigate the micro drone in 3-D spaces. In addition, a deliberate mass-distribution across the body of the micro drone was made to generate restoration in orientation under disturbances or during actuations such that the micro drone always returns to the initial posture. Second, a dosage-controllable, remotely activated drug release system is achieved by a micro tube that has ratchet structure on its interior wall which traps a liquid droplet in the middle of the tube as a representative of liquid drug. As the tube with the droplet is immersed into liquid, air bubbles automatically form at both sides of the droplet. When the bubbles are excited by an external acoustic field, mass exchange between the liquid droplet and the surrounding liquid occurs. The amount of the dosage can be precisely tuned by the duty ratio and the number of cycles. The releasing system was integrated with the drone demonstrating an on-demand controllable releasing function while swimming. Last, the acoustic signal transmission was modeled by ANSYS package to explore the possibility of remote actuations of micro drones inside human body. It was found that the bending waves in the rigid layer excited by piezo actuators significantly dissipate when the rigid layer is in direct contact with a soft (phantom) tissue. However, by coupling a proper medium between the rigid layer and the tissue, the acoustic signal can be effectively transmitted to a target across the soft tissue. All the above results imply that the proposed drone and actuation mechanism have become one step closer to their practical application.


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Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
Liu, Fang-WeiFAL29@pitt.eduFAL29
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Thesis AdvisorCho, Sung
Committee MemberRobertson,
Committee MemberKim,
Committee MemberSharma, Nitinnis62@pitt.eduNIS620000-0003-1872-0156
Date: 18 June 2021
Date Type: Publication
Defense Date: 4 March 2021
Approval Date: 18 June 2021
Submission Date: 9 April 2021
Access Restriction: 2 year -- Restrict access to University of Pittsburgh for a period of 2 years.
Number of Pages: 121
Institution: University of Pittsburgh
Schools and Programs: Swanson School of Engineering > Mechanical Engineering
Degree: PhD - Doctor of Philosophy
Thesis Type: Doctoral Dissertation
Refereed: Yes
Uncontrolled Keywords: Micro drone, Acoustic, Microfluidics
Date Deposited: 18 Jun 2022 05:00
Last Modified: 18 Jun 2023 05:15


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