A thrombin‐responsive closed‐loop patch is developed for prolonged heparin delivery in a feedback‐controlled manner. This microneedle‐based patch can sense activated thrombin and subsequently releases heparin to prevent coagulation in the blood flow. This “smart” heparin patch can be transcutaneously inserted into skin without drug leakage and can sustainably regulate blood coagulation in response to thrombin.

Direct analysis and IR-MALDESI mass spectrometry imaging of fresh mouse bones that underwent no chemical treatments other than flash-freezing.