Probing Lead Ion Contamination in Aqueous Solution Through Bio-Inspired Surface Modification of Gold Nanoparticles on D-Shaped Fiber

A key challenge for detection circuits is the capability of rapidly quantifying target molecules with lower level of limit of detection. An additional obstacle in this direction is also the ease of fabrication of sensing probes. In such cases, D-shaped optical fiber probe can be utilized to shrink the footprint as well as provide ample scope of surface modification of the sensing surface. The detection of D-shaped fiber probe functionalized by chitosan modified gold nanoparticle is comprehensively and procedurally investigated and demonstrated toward detection of lead ions. Through adoption of a very inexpensive intensity interrogation approach, the scheme renders limit of detection of 2 ppb, with a remarkable linearity of ~0.98 within a range 1-20 ppb. Even in presence of interfering ions, the scheme provides brilliant selectivity toward lead, suggesting the potential for this scheme in integrated photonic architectures.