Pneumatic Delivery of Microgrippers and Biodegradable Foldable Shapes

Gastrointestinal diseases, including colorectal cancer, gastric cancer and peptic ulcer are prevalent diseases worldwide with high mortality rate. Nowadays, the best solution to gastrointestinal diseases is early detection. Biopsy is currently the one of the most common detection techniques, but due to the limited detection area by biopsy, some early stage GI diseases may be overlooked, leading to misdiagnosis or even death of the patients. Increasing detection area and sample size is the key to ensure improved detection for early stage GI diseases. Innovative surgical tools such as untethered, thermally actuated microgripper, which are smaller than a millimeter in diameter, have shown its potential to mass sample the GI tract including certain hard to reach areas. With large number of microgrippers used in biopsies, the targeted area can be thoroughly sampled. Previously, syringe was used for the delivery of microgrippers. However, syringe was unable to deliver large amount of microgrippers with high efficiency and the delivery pressure was not controllable. 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 using a pneumatic delivery system. The new delivery system provides a consistent delivery pressure with delivery efficiency up to 83.7 ± 8.32%. We are able to deliver a large number of microgrippers in an efficient manner in both ex or in-vivo environment. However, the existing untethered devices contain materials such as Cu, Cr and Ni, which are not degradable in human body.The search for biodegradable materials that can be used for fabrication of devices is crucial to future application of these inventions. I conducted a variety of experiment to investigate the degradation properties of different materials, fabricate various shapes and structures with selected materials and observe the folding performance in ex-vivo environment. Mo, MgO, Mg and Fe can degrade in PH 7.4 PBS solution in a wide range of rate. Folding of the shapes could be initiated by MgO/Mo stress layer and the folding angles were adjusted by the thickness of stress layer