Interleukins proved to be valuable biomarkers for different diseases. Interleukins 1β, 6, and 12 can be used as biomarkers for brain cancer diagnosis, and therefore this paper proposed a needle stochastic sensor based on protoporphyrin IX immobilized in nanodiamond paste for fast screening of biological samples such as whole blood, urine and brain tumoral tissue for these interleukins. The results obtained using this needle stochastic sensor proved that the interleukins 1β, 6, and 12 can be reliable determined from whole blood, urine and brain tumoral tissue, with recoveries higher than 96.00 %, with relative standard deviations lower than 1.00 %.

Two miniplatforms based on stochastic microsensors designed using Nitrogen (9.3%) and Boron (2.4%) - dopped graphene (NB-DG) modified with frutafit HD and frutafit TEX were designed and validated for the assay of MLH1, MSH2, MSH6, PMS2, and of KRAS in whole blood, urine, saliva, and tumoral tissues. The sensitivities recorded using the miniplatform based on frutafit TEX were higher (MLH1:1.07×104, MSH2: 5.31; MSH6: 1.58×103; KRAS: 1.36×10-2 s-1 μg-1 mL) than those recorded when frutafit HD was used. A lower value of the limit of determination (0.32 fg mL-1) was recorded for the frutafit HD based miniplatform when used for the assay of MLH1, while the lowest value of the limit of determination for the assay of KRAS (2.2 fg mL-1) was recorded when the frutafit TEX was used in the design of the miniplatform. The percent recoveries of MLH1, MSH2, MSH6, PMS2, and of KRAS in whole blood, urine, saliva, and tumoral tissues were higher than 99.00 with RSD (%) values lower than 0.08%.

Interleukins proved to be valuable biomarkers for different diseases. Interleukins 1β, 6, and 12 can be used as biomarkers for brain cancer diagnosis, and therefore this paper proposed a needle stochastic sensor based on protoporphyrin IX immobilized in nano-diamond paste for fast screening of biological samples, such as whole blood, urine and brain tumoral tissue, for these interleukins. The results obtained using this needle stochastic sensor proved that the interleukins 1β, 6, and 12 can be reliably determined from whole blood, urine and brain tumoral tissue, with recoveries higher than 96.00% and with relative standard deviations lower than 1.00%. The validation of the method was performed using whole blood and tissue samples collected from the patients confirmed with brain tumor.

Bioanalysis of MLH1, MSH2, MSH6, PMS2, and KRAS using combined microplatforms based on graphenes and inulins proved to be a key factor in diagnosis of colorectal cancer.