TIPD104: SIR(Surface Insulation Resistance) application

Customer is asking if we have solution to measure the current with 100nA or less. The application is to sensing the leakage current in between the special materials.

If we have total solution or suggestion, please advice. thanks.

Here is the competition info that customer is in studying.

https://www.analog.com/en/design-center/reference-designs/hardware-reference-design/circuits-from-the-lab/cn0407.html#rd-evaluationNtest