Non-enzymatic electrochemical detection of methylglyoxal in saliva using a polyaniline/nickel oxide nanohybrid biosensor: A noninvasive approach for diabetes diagnosis

Methylglyoxal (MG) is a prominent biomarker for diabetic syndromes and ageing disorders. In the present study, a non-enzymatic electrochemical detection of MG in human saliva at low levels was achieved via polyaniline/nickel oxide nanohybrid modified graphite sheet (PANI/NiO/GS) electrode. The physical characteristics and structure of the PANI/NiO nanohybrid showed the presence of NiO flakes embedded within the irregular granular like structure of PANI matrices. Chronoamperometric (CA) analysis of the nanohybrid electrode showed excellent electrocatalytic activity towards MG with the linear range from 1 to 10 μM in 0.1 M phosphate buffer (pH 7). The proposed sensor boasts a high sensitivity of 1.136 μA.μM⁻¹ including a lower limit of detection of 2.64 nM. The real-time functionality of the proposed biosensor was also employed to estimate the precise quantification of MG levels in both healthy and diabetic patients' saliva. For the healthy and diabetes samples, the recovery values for MG were 95–103 % and 102–111 %, respectively. This approach is truly noninvasive and circumvents the discomforts associated with the traditional modalities.