4. Conclusion
In summary, we have developed a simple approach on a treeshaped paper with self-calibration for monitoring glucose in serum sample by bienzyme colorimetric assays. This paper-based system only requires a common camera or cell phones. The color results
are observed by naked eyes or analyzed by software. Moreover, the testing model provides an affordable, rapid, equipment-free, deliverable and easy-to-use tool for the practical application in the areas of life science and environmental protection.