However, due to complex sample handling requirements(e.g., multiple pipetting) and high costs of fabrication, these formsare not always ideal for biosensing applications in remote areas or resource-limited settings, which would most benefit from PDA’sinstrument-free and naked-eye detection. Therefore, the develop-ment of PDA sensors in the form of a membrane strip, which arelight, low cost, and easy to use, will be of significant benefit.