3D-printed engineered bacteria-laden gelatin/sodium alginate composite hydrogels for biological detection of ionizing radiation

Nuclear safety is a global growing concern, where ionizing radiation (IR) is a major injury factor resulting in serious damage to organisms. The detection of IR is usually conducted with physical dosimeters; however, biological IR detection methods are deficient. Here, a living composite hydrogel consisting of engineered bacteria and gelatin/sodium alginate was 3D-printed for the biological detection of IR. Three strains of PrecA::egfp gene circuit-containing engineered Escherichia coli were constructed with IR-dependent fluorescence, and the DH5a strain was finally selected due to its highest radiation response and fluorescence. Engineered bacteria were loaded in a series of gelatin/sodium alginate matrix hydrogels with different rheology, 3D printability and bacterial applicability. A high-gelatin-content hydrogel containing 10% gelatin/1.25% sodium alginate was optimal. The optimal living composite hydrogel was 3D-printed with the special bioink, which reported significant green fluorescence under ?-ray radiation. The living composite hydrogel provides a biological strategy for the detection of environmental ionizing radiation.

Automated summary

Nuclear safety is globally concerning due to the harm caused by ionizing radiation to organisms. This study developed a living composite hydrogel consisting of engineered bacteria and gelatin/sodium alginate for the biological detection of ionizing radiation. The hydrogel showed significant green fluorescence under gamma-ray radiation, providing a biological strategy for environmental radiation detection.