UBC Theses and Dissertations
Ferrofluid enabled micro actuators for endoscopic bio-imaging and analysis Jayhooni, Sayed Mohammad Hashem
The range of potential applications that micro rotary motors offer is extremely wide and one of the promising categories of applications is for medical devices. Along this direction, micro motors are being used for endoscopic applications to perform a full 360° circumferential scan in order to detect cancer located at the inner surface of the internal organs of humans. Flexibility and maneuverability are two of the most important mechanical characteristics that an endoscopic device is expected to provide. This allows the catheter to pass through curved and confined internal body channels, achieving repeatable and precise positioning of the device without damaging tissue. Early detection and diagnosis is the most effective way to tackle different diseases. This, however, remains a challenge due to the lack of accurate detection technology. The problem is further exacerbated in cases of peripheral lung cancer, in which the tumor grows on narrow bronchi that are difficult to probe. The present thesis targets designing and developing novel electromagnetic micro actuators based on a ferrofluid levitation mechanism for side-viewing endoscopic applications with Raman spectroscopy and potentially with other modalities, including ultrasound and optical coherence tomography. A tubular micro rotary stepping actuator, custom-designed with a ferrofluid levitation mechanism, is integrated with a Raman probe, for the first time, to scan a probing laser beam sideways for angle-resolved Raman excitation and signal collection, towards enabling the detection of lesion-induced biochemical changes in vivo and in real-time. The side-viewing scanning resolution is enhanced by developing stepping actuation of the micromotor with higher rotational performance. A microfabricated prototype is evaluated using test chemicals, harvested animal lung tissue ex vivo, as well as a murine colon model in situ and human skin in vivo. All the test results show excellent agreement with reported reference data while revealing a wavenumber accuracy greater than 99%. This thesis indicates that micro actuator-assisted endoscopic Raman spectroscopy is a promising technology for luminal tissue analysis.
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