Autonomous untethered microinjectors for gastrointestinal delivery of insulin

The delivery of macromolecular drugs via the gastrointestinal (GI) tract is challenging. Macromolecular drugs display low stability and poor absorption across the intestinal epithelium. While permeation-enhancing drug delivery methods can increase the bioavailability of low molecular weight drugs, the effective delivery of high molecular weight drugs across the tight epithelial cell junctions remains a formidable challenge. Here, we describe autonomous microinjectors that can efficiently penetrate the GI mucosa and deliver insulin systemically. In addition, we performed in vitro studies to characterize insulin release and the penetration capacity of microinjectors and measure in vivo release of insulin in live rats. We found that the microinjectors administered within the luminal GI tract could deliver insulin trans-mucosally to the systemic circulation at similar levels to intravenously administered insulin. Due to their small size, tunability in sizing and dosing, wafer-scale fabrication, and parallel, autonomous operation, we anticipate that these novel microinjectors could significantly advance drug delivery across the GI tract mucosa to the systemic circulation.