A simply synthesized, silver ions-doped porous gold microparticles-based SERS aptamer sensor for ultrasensitive and broad-range quantitative detection of IL-6.

Background: The multifunctional cytokine interleukin-6 (IL-6) plays a pivotal role in chronic and acute inflammatory responses, underscoring the importance of accurately determining IL-6 levels for early diagnosis, prevention, and treatment of inflammation.

Results: This study developed a versatile and innovative single-particle surface-enhanced Raman spectroscopy (SERS) sensing platform for the precise and sensitive quantification of IL-6 in complex samples using a novel one-pot synthesized, silver ions-doped three-dimensional porous gold microparticles (PGMs) with abundant hot spots for robust SERS enhancement. By rationally designing rich cytosine-Ag-cytosine base pairs between IL-6 aptamers and complementary chains on the PGMs, we harnessed the SERS-enhancing effect to achieve highly sensitive and specific IL-6 quantification within a wide range of 10 to 10 mg/mL and a limit of detection (LOD) of 0.093 pg/mL. Moreover, the accurate detection of IL-6 in spiked serum samples exhibited a remarkable recovery rate ranging from 97.2 % to 107.6 %.

Significance: This aptamer sensor provides an alternative tool for cost-effective, sensitive and broad-range IL-6 detection, which would contribute to the early detection of inflammation and pave the way for timely interventions and improved patient outcomes.