<p>Miniaturization of technologies to milli-, micro- and nanoscale offers numerous advantages for diagnostic and therapeutic biomedical applications. In comparison to their macro-scale counterparts, these small-scale systems are more portable, less invasive and less costly. They can facilitate rapid, sensitive and high throughput detection of abnormalities, help track disease progression, reduce sample consumption and improve therapeutic efficacy of drug delivery while decreasing systemic toxicity. Thus, there is clearly a need for creating innovative milli-, micro- and nanoscale tools that can uncover new possibilities in detection and treatment of various types of diseases. The overall objective of this dissertation was to develop novel small-scale technologies that could help enhance diagnostic and/or therapeutic outcomes in patients with cancer, opioid addiction and inflammatory bowel disease. First, we developed an echogenically stable nanodroplet ultrasound contrast agent with potential applications in extravascular molecular imaging of tumors and targeted cancer therapies. Then, we created a polymer blend microsphere system that could be integrated in prescription opioid tablets to develop an abuse-deterrent formulation against smoking. Finally, we designed a release system for localized delivery of aminosalicylates from magnetically actuated millirobots in the colon to improve therapeutic outcomes in patients suffering from inflammatory bowel disease. Overall, the technologies we developed could serve as a basis for designing diagnostic and therapeutic tools that are superior to currently existing platforms.</p>