This paper presents the construction and characterization of an amperometric immunosensor based on the graphene/gold nanoparticles (AuNPs/GO) nanocomposite for the detection of the bladder cancer biomarker, apolipoprotein A1 (Apo-A1). The morphological analysis of the AuNPs/GO nanocomposite demonstrated an almost spherical shape of AuNPs and the successful coverage of their surface by graphene oxide. An increased G peak and decreased D peak after the association of AuNPs with GO, implied a reduction in graphene defects. The X-ray photoelectron spectroscopy (XPS) indicated a significant decrease in the quantity of oxygen-containing functional groups in the AuNPs/GO nanocomposite, as compared to the original GO. Furthermore, the developed sensor demonstrated commendable sensitivity and selectivity, with a wide linear range for Apo-A1 detection. Importantly, the immunosensor exhibited remarkable stability over a period of 14 days, signifying its potential for practical applications.

Apolipoprotein A1 (ApoA1) is the major protein component of high density lipoprotein (HDL) cholesterol in blood, and ApoA1 genetic polymorphisms modulate the blood lipid profiles. This study was conducted in order to investigate the association between three genetic polymorphisms (rs670, rs5069, and rs5070) of ApoA1 and blood lipid profiles in postmenopausal Korean women. A total of 130 post- menopausal women who visited a hospital in order to undergo screening tests were subjects of this study. Genetic polymporphisms and blood lipid profiles were determined using a direct sequencing and spectrophotometric assay, respectively. A significant linkage disequilibrium was observed between all tested single nucleotide polymorphisms. ApoA1 rs5070 genetic polymorphism showed a marginally significant association with HDL cholesterol levels (p=0.066). After adjusting for age, body mass index, smoking, alcohol drinking, medication, hypertension, and diabetes mellitus, we found that the ApoA1 rs5070 genetic polymorphism is a significant determinant of HDL cholesterol levels (β=4.421, p=0.037). According to the results of this study, ApoA1 rs5070 genetic polymorphism may be an important genetic marker associated with HDL cholesterol in postmenopausal Korean women.