Fabrication of biosensors by bacterial printing on different carriers using a laser printer

Abstract

In this study, a commercial laser printer was used for the first time to print bacteria on different substrates as bacterial carriers to be used in biosensors. For this purpose, the spores of Geobacillus stearothermophilus and Bacillus atrophaeus were mixed with the printer toner and used as a bio-powder in a conventional laser printer to print on a polypropylene film (PF) or copy paper (CP), transfer paper (TP), and filter paper (FP).‏‏ Subsequently, the effects of the substrate material, print density, print pattern, and color intensity were investigated on the number of bacteria recovered. It was also found that FP was the best substrate, followed, with a significant difference, by TP, for the maximum number of bacteria recovered. Moreover, a color intensity of 100% was found the most appropriate. However, changing print density and pattern showed differences in their effects on bacterial numbers for the two strains tested albeit the differences were not significant. ‏‏Based on the results obtained, it may be claimed that laser printers can be effectively used for transferring bacteria to paper substrates and used in fabricating biosensors. Printing capabilities and novel toner bio-powders are exploited to choose the proper number of printed bacteria to adapt the printed substrates for use in manufacturing bacterial biosensors.