For the measurements with levodopa (MW = 197.19 g/mol, prod. no. 1361009, Sigma-Aldrich), a stock solution of 3 mM in PBS was prepared. 5 µL of the stock solution was pipetted into 145 µL of SWCNT solutions (1 nM) in the wells of a 96-well plate. The stock solution was diluted to match concentrations of 1 nM to 100 µM in the well plate. For screening, the well plate was filled with the barcode column-wise, whereby every row consisted of a different SWCNT surface chemistry. For background subtraction, one row was filled with only buffer (PBS). For each levodopa concentration the response of the barcode was measured in triplicates. The intensity change 𝐼𝐶 was calculated by referencing the voltage 𝑉 to the voltage 𝑉 " before levodopa addition for each well 𝐼𝐶 = 𝑉 -𝑉 " 𝑉 "