Sarcosine Biosensor Based on Pt/g-C3N4 Nanocomposites with High Electrocatalytic Activity

Sarcosine has been shown to be a new biomarker for prostate cancer that is superior to prostate-specific antigen (PSA). By detecting the concentration of sarcosine in the human body, accurate screening and diagnosis of prostate cancer can be achieved in clinical practice. However, the sarcosine level is extremely low in human serum or urine, and accurate detection of sarcosine concentration is difficult. More work is needed to prepare sarcosine biosensors with good anti-interference performance. In this work, we prepared a sarcosine biosensor using a highly electrocatalytically active nanocomposite comprising platinum/carbon nitride (Pt/g-C3N4) as the electrode modification material. The porous lamellar graphite phase carbon nitride (g-C3N4) prevents the agglomeration of Pt nanoparticles and keeps the Pt nanoparticles in a highly dispersed state. The constructed sarcosine biosensor achieves high sensitivity and can selectively detect low concentrations of sarcosine. Its linear detection range is 2–70 μM, and the limit of detection (LOD) is 0.8 μM (S/N = 3). The prepared sarcosine biosensor shows relatively good performance in terms of resistance to interference caused by electroactive substances and provides the potential to be applied in serum for accurate detection of sarcosine.