A biomimetic skin microtissue biosensor for the detection of fish parvalbumin

In this paper, a biomimetic skin microtissue biosensor was developed based on three-dimensional (3D) bioprinting to precisely and accurately determine fish parvalbumin (FV). Based on the principle that allergens stimulate cells to produce ONOO^- (peroxynitrite anion), a screen-printed electrode for the detection nanomolar level ONOO^- was innovatively prepared to indirectly detect FV based on the level of ONOO^- release. Gelatin methacryloyl (GelMA), RBL-2H3 cells, and MS1 cells were used as bio-ink for 3D bioprinting. The high-throughput and standardized preparation of skin microtissue was achieved using stereolithography 3D bioprinting technology. The printed skin microtissues were put into the self-designed 3D platform that integrated cell culture and electrochemical detection. The experimental results showed that the sensor could effectively detect FV when the optimized ratio of RBL-2H3 to MS1 cells and allergen stimulation time were 2:8 and 2 h, respectively. The linear detection range was 0.125-3.0 μg/mL, and the calculated lowest detection limit was 0.122 μg/mL. In addition, the sensor had excellent selectivity, specificity, stability, and reliability. Thus, this study successfully constructed a biomimetic skin microtissue electrochemical sensor for PV detection.