Semiconducting polymer dot-based wireless electrochemical aptasensor for detection of aging-related TGF-β1 and IL-6

The senescence-associated secretory phenotype (SASP) is closely linked to aging by promoting inflammation and tissue degradation. Sensing SASP is crucial for early detection of and intervention in age-related diseases to enhance therapeutic outcomes. Herein, SASP-selective sensors (transforming growth factor [TGF]-β1 and interleukin [IL]-6 probes) were designed by utilizing TGF-β1/IL-6 aptamers-functionalized copper-immobilized polymer dots that promoted specific binding between TGF-β1/IL-6 aptamers on the probe surface with aging factors (TGF-β1 and IL-6).

The selective binding was reflected by changes in the conductivity of the probes. The TGF-β1 and IL-6 probes showed high sensitivity towards TGF-β1 and IL-6, with limits of detection of 193.09 pg/mL for the TGF-β1 (R² = 0.9989) and 16.49 pg/mL (R² = 0.9998) for IL-6 probes. In vitro study using senescent cells confirmed that the probes could selectively detect TGF-β1 and IL-6, indicated by increased resistance with longer incubation times (TGF-β1_72h = 2.775 MΩ, IL-6_72h = 2.401 MΩ). Furthermore, the TGF-β1 and IL-6 probes exhibited excellent detection performance in in vivo samples from aging mouse models when monitoring the levels of TGF-β1 and IL-6 at different times after lenti soup injection and at different mouse ages (6-20 months). Additionally, the electrical signals generated during sensing can be displayed on a smartphone via a wireless sensing system.

TGF-β1 and IL-6 probes provide a sensitive, specific and accessible diagnostic platform for senescence aging factors monitoring, which are expected to be an essential tool that transforms the analysis of aging and age-related diseases.