High-performance catalytic strips assembled with BiOBr Nano-rose architectures for electrochemical and SERS detection of theophylline

The recent developments in the healthcare sector and administration of various drugs into human systems demands for ultra-sensitive detection of drugs. Theophylline (TP) is one such drug extensively consumed for numerous respiratory disorders. In order to avoid the side effects caused by TP, consistent monitoring of it is of prime importance. Here, we developed a multifunctional screen-printed carbon electrode (SPCE) based catalytic strips loaded with BiOBr nano rose (BOB-NR) like architectures. The SPCE catalytic strips are exploited for dual mode (electrochemical and surface enhanced Raman spectroscopy (SERS)) detection of toxic drug TP. The hydrothermally prepared BiOBr nanostructures are thoroughly characterized for its physical properties and attached to SPCE through a unique gravity offered drying (GOD) strategy. The BOB-NR offered less charge transfer resistance and diffusion resistance upon the electrochemical investigation indicating its superior electrocatalytic capabilities. It reflected on projecting a wide linear range and excellent limit of detection (LOD) for electrochemical detection of TP. On the other side, the plasmonic Au layer deposited on the BOB-NR loaded SPCE strips (BiOBr/[email protected]) are employed for rapid SERS detection of TP. The higher enhancement factor of 107 is obtained for BiOBr/[email protected] strips for TP detection owing to its catalytic activity between Au layer and BiOBr nanostructures. The Au layer aids in developing a localized electromagnetic hotspot and the charge transfer process arising from BiOBr to Au all together plays a critical role in achieving a superior SERS performance. The fabricated multifunctional catalytic strips are also tested for its stability, repeatability and real-world analysis. Our established platform for detection of toxic drugs promises to be greater prospect for portable, rapid and on the spot analysis.