Aydın, Elif BurcuAydın, MuhammetSezgintürk, Mustafa Kemal2023-05-062023-05-0620231616-51871616-5195https://doi.org/10.1002/mabi.202200390https://hdl.handle.net/20.500.11776/12288An early on time detection of breast cancer significantly affects the treatment process and outcome. Herein, a new label-free impedimetric biosensor is developed to determine the lowest change in the level of calreticulin (CALR), which is a new biomarker of breast carcinoma. The proposed immunosensor is fabricated by using reduced graphene oxide/amino substituted polypyrrole polymer (rGO-PPyNH2) nanocomposite modified disposable electrode. The anti-CALR antibodies are first attached on the rGO-PPyNH2 nanocomposite coated electrode through glutaraldehyde crosslinking; the CALR antigens are then immobilized with the addition of CALR antigens to form an immunocomplex on the sensing surface. This immunocomplex induces considerably larger interfacial electron transport resistance (R-ct). The variation in the R-ct has a linear relationship with CALR level in the detection range of 0.025 to 75 pg mL(-1), with a detection limit of 10.4 fg mL(-1). The suggested biosensor shows high selectivity to CALR, good storage stability (at least 5 weeks) and suitable reproducibility results as shown in quality control chart. The designed immunosensor is utilized to analyze CALR levels in human sera with satisfying results. This immunosensor provides a novel way for the clinical determination of CALR and other cancer biological markers.en10.1002/mabi.202200390info:eu-repo/semantics/closedAccesscalreticulinimpedimetric immunosensorreagentless analysisreduced graphene oxideGraphene OxideFunctionalized GrapheneRaman-SpectroscopyLabel-FreeBiosensorPolymerImmobilizationSurfaceCancerReductionArticle231Q1WOS:0008933392000012-s2.0-8514397432336419333Q1