Proteomic identification at the point of care would be valuable for a wide variety of applications and importance, including clinical diagnostics, food safety, and environmental monitoring. Traditional proteomic identification makes use of protein digestion of interesting sample and could be detected using matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Protein digesting reaction in vitro often wastes much time (usually overnight) and reagent volume, and then the reaction products should be transferred to the MS sample plate and air-dried. The analysis process is not effective for convenience and wastes time and analysis sample.

For more effective protein identification, we construct a novel micro-droplet chip system with auto-positioning and enriching the sample for rapid analysis. Presently, MALDI-TOF MS has been widely used in proteomic research, and it is the important issue to identify the micro sample. Utilizing the novel micro-droplet chip, protein sample would be co-crystallized with MS matrix and concentrated on the detection area. Through drying the sample and matrix mixture, protein digestion would be reacting at the same time. The sample would be digested to smaller dried peptides on chips and then detected with matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Comparing to the traditional methods, the proteomic identification chip offers four advantages: 1. shortening reaction and analysis time (total ~2.5 hours); 2. auto-positioning and enriching the sample concentration; 3. lower reaction volumes (1~5 μL); 4. entire process sequentially on the chip.