Mix to Validate: To advance the rate of novel protein therapies entering the clinic, we provide researchers a facile tool for protein drug efficacy testing in animal models in a high throughput manner. Here, we utilize the concept of PEGylating proteins through complementary interactions between His-tag and Ni2+ complex of NTA, a well-established practice in protein research, to improve blood half-life of therapeutic protein candidates after systemic administration in vivo.