In the first part, an electrochemical biosensor for the detection of breast cancer cell endogenous protein. The biosensor was designed based on a three-component probe consisting of a GNP-thionine hybrid structure as an electrochemical tag, DNAzyme catalytic molecule to increase sensitivity and performed as recognition element, and magnetic nanoparticle as probe collecting site. The protein marker acts as a stimulus cofactor for the enzyme molecule, breaking the substrate filament and decreasing the electrochemical signal. The results show that this biosensor can detect this protein marker in the linear range of (1.0E-06 to 1.0E+01) pg/ml, with a detection limit (1.0129E-07 pg/ml). In the second part, an optical sensor for detecting methanol in presence of various percentage ratios of ethanol, which involved mesoporous silica nanoparticle (MSN) loaded with sodium nitroprusside (SNP) that acted as a nucleophile in basic medium to form a red color complex. The results show that this sensor can detect methanol in the linear range of 600 mg/L to 2600 mg/L with a detection limit of 153.3 mg/L
