Pathological bio-mineralization can be induced by diseases such as preeclampsia. Inspired by these naturally occurring bio-mineralization processes, we have designed a process called protein-controlled peptide assembly tandem peptide-templated bio-mineralization. The technique provides bio-context-associated data on the activity of target proteins, and facilitates the evaluation of protein function in the associated biological microenvironment. It is a bio-mimetic process that leads to the formation of Ag nanoparticle-decorated peptide nanowires, which can offer efficient signal amplification with high sensitivity for biosensing applications. Consequently, high-temperature requirement factor A1 (HtrA1) can be assayed quantitatively in clinical serum samples to offer information for the diagnosis of preeclampsia and the improved treatment of the disease. The results suggest that the process has considerable potential for use in clinical practice.