Recently, medical organizations and research disciplines have switched to employing affordable biosensors. Biosensors have become more critical in drug development, drug identification, bio-medicine, food safety, security, protection, and ecological research. It has directly contributed to developing specialized and reliable diagnostic equipment that uses biological sensing components as biosensors. Different analytes, biological receptors, and transducer concepts are used in biosensors. In recent years, innovative sensing platforms have been developed employing screen-printed electrodes (SPEs), which are inexpensive, simple, and quick mass production through thick film technology. During my Ph.D., I concentrated on designing, constructing, and validating several SPE-based (bio)sensors to identify biologically active compounds important for healthcare applications, demonstrating their significant potential as a suitable sensing platform. I created (bio)sensors for a variety of analytes, from nucleic acid to small molecules, with specific modification strategies to endow the platforms with selectivity toward the species of interest. I developed disposable electrochemical (bio)sensors in two papers based on modifying with single-walled carbon nanotubes (SWCNT) and molecularly imprinted polymers. In the first case, SWCNT-modified SPCE as disposable electrochemical sensors was proposed for quick determination of dasatinib in pharmaceutical formulations, demonstrating an excellent boosting effect on the oxidation response of dasatinib. The sensor was able to monitor different dasatinib concentrations with a limit of detection of 0.06 M. In the second paper, the SPE surface was modified with poly tyrosine-chitosan and combined with a self-assembly surface molecular imprinting approach to develop horseradish peroxidase (HRP)-imprinted biosensor. Additionally, the molecularly imprinted electrochemical biosensor for determination of HRP was expanded for the detection of H2O2 as 7 enzymatic substrates. The HRP-imprinted biosensor was determined H2O2 and HRP with detection limits of 2.18 nM and 9.39 × 10-8 mg/ml (2.34 pM), respectively. The last paper was related to developing a DNA-based bio-assay for determining Haemophilus influenza through bioconjugation of citrate-capped silver nanoparticles with pDNA toward target sequences detection. The ultra-sensitive fabricated optical genosensor was detected the synthesized probe (SH-5-AAT TTT CCA ACT TTT TCA CCT GCA T-3') of Haemophilus influenza with great selectivity and sensitivity after hybridization with cDNA with the low limit of quantification of 1 zM (zeptomolar). Finally, the designed genosensor is a significant diagnostic strategy for detecting Haemophilus influenza with great selectivity.Recently, medical organizations and research disciplines have switched to employing affordable biosensors. Biosensors have become more critical in drug development, drug identification, bio-medicine, food safety, security, protection, and ecological research. It has directly contributed to developing specialized and reliable diagnostic equipment that uses biological sensing components as biosensors. Different analytes, biological receptors, and transducer concepts are used in biosensors. In recent years, innovative sensing platforms have been developed employing screen-printed electrodes (SPEs), which are inexpensive, simple, and quick mass production through thick film technology. During my Ph.D., I concentrated on designing, constructing, and validating several SPE-based (bio)sensors to identify biologically active compounds important for healthcare applications, demonstrating their significant potential as a suitable sensing platform. I created (bio)sensors for a variety of analytes, from nucleic acid to small molecules, with specific modification strategies to endow the platforms with selectivity toward the species of interest. I developed disposable electrochemical (bio)sensors in two papers based on modifying with single-walled carbon nanotubes (SWCNT) and molecularly imprinted polymers. In the first case, SWCNT-modified SPCE as disposable electrochemical sensors was proposed for quick determination of dasatinib in pharmaceutical formulations, demonstrating an excellent boosting effect on the oxidation response of dasatinib. The sensor was able to monitor different dasatinib concentrations with a limit of detection of 0.06 M. In the second paper, the SPE surface was modified with poly tyrosine-chitosan and combined with a self-assembly surface molecular imprinting approach to develop horseradish peroxidase (HRP)-imprinted biosensor. Additionally, the molecularly imprinted electrochemical biosensor for determination of HRP was expanded for the detection of H2O2 as 7 enzymatic substrates. The HRP-imprinted biosensor was determined H2O2 and HRP with detection limits of 2.18 nM and 9.39 × 10-8 mg/ml (2.34 pM), respectively. The last paper was related to developing a DNA-based bio-assay for determining Haemophilus influenza through bioconjugation of citrate-capped silver nanoparticles with pDNA toward target sequences detection. The ultra-sensitive fabricated optical genosensor was detected the synthesized probe (SH-5-AAT TTT CCA ACT TTT TCA CCT GCA T-3') of Haemophilus influenza with great selectivity and sensitivity after hybridization with cDNA with the low limit of quantification of 1 zM (zeptomolar). Finally, the designed genosensor is a significant diagnostic strategy for detecting Haemophilus influenza with great selectivity.