A Polydiacetylene (PDA) Based Dual-Mode Optical Sensor for the ppb Level Selective Detection of Biogenic Polyamines

Biogenic polyamines (BPAs), specifically spermine and spermidine, play vital roles in cellular physiology, influencing processes like cell growth and proliferation. Beyond their cellular implications, these amines serve as biomarkers for cancer and aging-related diseases. This study presents a dual-output optical sensor for BPAs using polydiacetylene (PDA). The sensor utilizes alendronate's phosphate groups as recognition units for BPAs in liquid and solid phases. Ammonium groups of BPAs interact with negatively charged alendronate-modified PDA (PDAPH) liposomes causing a color change from blue to red accompanied by a gradual increase in fluorescence output at λmax 622nm. The sensor exhibits high sensitivity with low detection limits of 4.3 ppb and 5.1 ppb for spermine and spermidine in colorimetric analysis, and lower limits of 1.6 and 1.4 ppb in fluorimetric measurements respectively, demonstrating its dual output ability. PDAPH liposomes also respond to cadaverine and putrescine indicating the probe's ability to detect key BPAs. The sensor shows minimal responses to interfering species, confirming its selective affinity towards BPAs. Practical validation in real water, urine, and serum samples demonstrates the sensor's efficiency. Immobilization of PDAPH liposomes into sodium alginate results in the creation of PDA beads. These beads exhibit a discernible color change when exposed to BPA concentrations exceeding 0.3μM with a sufficiently low detection limit of 11.7 ppb in the solid phase. These findings highlight the efficiency of the PDAPH liposome sensor for accurate and reliable biogenic polyamine detection.