Procollagen type 1 N-terminal propeptide immunoassay on zeolite-modified gold interdigitated electrode for diagnosing osteoporosis

Abstract

Osteoporosis is a condition that reduces the strength and density with bones and leads the fragile and fracture formation. Osteoporosis is increasing among elders, and it do not show any symptom until the first fracture forms. Osteoporosis diagnosis is usually done by quantifying the patient’s bone mineral density (BMD). Procollagen type 1 N-terminal propeptide (P1NP) is highly correlated with BMD and helps for detecting and monitoring osteoporosis. This research was focused to generate a sensitive sandwich immunoassay to detect P1NP on interdigitated gold electrode (AuIDE) sensor. Anti-polyclonal P1NP antibody was utilized as a capture probe and placed on IDE through amine-modified zeolite. The current response of polyclonal antibody was increased by enhancing the antibody concentration and saturated at 8 μg/mL. On the antibody immobilized surface, P1NP sandwich was made by monoclonal antibody and attained the detection limit to 2 ng/mL on a linearity at 2–64 ng/mL [y = 2.426x +1.1497; R2 = 0.9957]. In addition, P1NP spiked serum shows a gradual increment of current responses with increasing P1NP concentrations, while there is no noticeable response recorded with only serum, indicating the selective detection of P1NP.