Background: This study is focused on the design and manufacture of a biosensor to detect the presence of the two chemicals Pb⁺² and ²²²Rn in soil and building materials. Materials and Methods: The biosensor is used on the basis of primers (ssDNA with high guanine). These are different sequences of nitrogenous bases. Biosensor-Ι and biosensor-ΙΙ have sequences as follow: 5′-AGGGTTAGGGTTAGGGTTAGGG-′3 and 5′-GGTTGGTGTGGTTGG-′3, respectively. The results show that the average ²²²Rn (BIOS-ΙI) was higher than ²²²Rn (BIOS-Ι). The average Pb⁺² (BIOS-Ι) was higher than Pb⁺² (BIOS-ΙΙ). Results: The ²²²Rn and Pb⁺² in the samples were ordered as following: Indian granite > soil loc 2 > Chinese granite > soil loc 1 > soil loc 3 > Iraqi mosaic > Iranian mosaic > Iraqi bricks > Iraqi thermostone blocks > Indian ceramic > cement1 > Iranian thermostone blocks > Turkish marble > Iranian ceramic > Iranian bricks > cement2 > Iranian marble. Conclusion: The levels of Pb⁺² and ²²²Rn in Chinese and Indian granites are higher than the acceptable limits. This method can be used for detecting radioactive and organic materials. It can also exclude radiation damage from field testing.