Electrochemical aptasensing reveals serum myelin alterations in diabetic neuropathy

Diabetic neuropathy (DN) is a complex neuropathic process in the peripheral nervous system caused by diabetes-induced hyperglycemia and its related pathways. Early-stage diagnostic methods to detect nerve damage in diabetic patients remain limited, hindering timely initiation of treatment. Delays in early diagnosis of neuropathy can exacerbate the disease, leading to diabetic foot ulcers and ultimately, amputations. Nerve damage in cases involving demyelination is associated with increase in serum myelin basic protein (MBP) levels. In this study, we developed electrochemical aptasensor-based prototype diagnostic method for the rapid, sensitive, specific, and low-cost Point-of-Care analysis of MBP. Disposable graphite electrodes modified with functionalized graphene oxide nanomaterial were utilized as the sensor surface, with immobilized MBP-specific aptamer forming the bioactive binding layer. At first, MBP binding in serum samples was monitored using electrochemical impedance spectroscopy. Following the validation of aptasensors, serum samples from 14 healthy volunteers and 16 patients with type II diabetes mellitus (with and without DN) were analyzed. A statistically significant difference in serum MBP levels was observed between healthy volunteers and diabetic patients, demonstrating the diagnostic potential of the method. The aptasensor-based method achieved a limit of detection (LOD) of 0.35 ng/mL, with a clinical application range from 0.35 to 128 ng/mL. As a proof-of-concept, the proposed aptasensor-based method showed a good agreement with ELISA in detecting MBP levels in serum samples. This study highlights the potential of the aptasensor-based method as a promising tool for early and accurate diagnosis of diabetic neuropathy and other conditions when MBP levels are altered.