Two stochastic microsensors based on the immobilization of inulins: inutec and frutafit in a paste obtained from a graphene decorated with nitrogen (10.8 %), and boron (2.6 %), and paraffin oil (IR purity) were designed, characterized and validated for the molecular recognition and analysis of mismatch repair proteins like MLH1, MSH2, MSH6, PMS2, and of KRAS in biological samples such as: whole blood, urine, saliva, and tumoral tissues. The sensor based on inutec exhibited the largest working concentration range (10 decades of concentration) and the lowest limit of determination (0.32fg mL-1) when used for the assay of MLH1, and the wider working concentration range (8 decades of concentration), and the lowest limit of determination (2.30fg mL-1) when used for the assay of MSH6. The sensor based on frutafit exhibited the largest working concentration range (10 decades of concentration) when used for the determination of KRAS, and the wider working concentration range (5 decades of concentration), and the lowest limit of determination (1.00fg mL-1) when used for the assay of PMS2. No influence of the modifier (inutec and frutafit) was recorded on the linear concentration range (10 decades of concentration), and on the limit of determination (1.00 fg mL-1) for the assay of MSH2. The recoveries of MLH1, MSH2, MSH6, PMS2, and of KRAS in whole blood, urine, saliva, and tumoral tissues were higher than 98.00 with RSD (%) values lower than 0.10 %.
Keywords: Cancer; Graphene; Mismatch repair proteins; Stochastic microsensors.
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