Electrochemical sensor featuring PdFeCo 1x ONPs on carbon paper for the sensitive determination of indole-3-lactic acid levels in serum samples Dieudonne Tanue Nde a,b,1 , Dhananjaya Merum b,1 , Gyawali Ghanashyam a , Jean Pierre Ndabakuranye c , Mohamed A. Habila d , Arghya Narayan Banerjee b,* , Sang Woo Joo b,** , Theophile Niyitanga a,*** , Haekyoung Kim a,**** a School of Materials Science and Engineering, Yeungnam University, 280 Daehak-Ro, Gyeongsan, 38541, Republic of Korea b School of Mechanical Engineering, Yeungnam University, Gyeongsan, 38541, Republic of Korea c School of Engineering, Department of Electrical and Biomedical Engineering RMIT University, Australia d Department of Chemistry, College of Science, King Saud University, P. O. Box 2455, Riyadh, 11451, Saudi Arabia A R T I C L E INFO Keywords: Electrochemical sensor Multi-metallic PdFeCo 1x ONPs@CP Serum samples, indole-3-lactic acid ABSTRACT A highly sensitive and selective electrochemical sensing platform with self-assembled porous 3-D trimetallic (Pd, Fe, and Co) hybrid anchored on a cost-effective and high-conducting carbon paper (CP) synthesized via a facile and cost-effective hydrothermal impregnation and thermal reduction technique was developed for determining indole-3-lactic acid (ILA) levels in buffer and serum samples. Before the analytical phase, the composite (PdFeCo 1x ONPs@CP electrode) was thoroughly characterized, and different methods were used to investigate the electrochemical properties. The combination of tri-metallics with CP-fbers improved sensing capacities in the linear range of 0.05–30 μM, with sensitivity and limits of detection of and 0.165 ± 0.013 μA/μM and 7.8 ± 0. 2 nM, respectively, towards ILA determination. Furthermore, the developed sensing platform was utilized for the analyses of ILA in sigma, human normal, and alcohol use disorder patients’ serum samples. Liquid chromatog- raphy in tandem with mass spectrometry was equally used to quantify ILA levels in the serum samples and the results of both methods were compared. 1. Introduction The consumption of alcohol is a major global cause of morbidity and mortality, accounting for 3 million deaths annually [1]. Individuals diagnosed with alcohol use disorder (AUD) display unique traits, including compulsive alcohol use, uncontrollably high alcohol intake, and negative emotional states when abstaining from alcohol [2,3]. One of the most common mental illnesses in the world, AUD primarily affects men [4]. Electroencephalography [5] and self-report questionnaires, such as CAGE [4], the Michigan alcoholism screening, and the AUD identifcation test (AUDIT) [6], are commonly utilized diagnostic tech- niques. Alternatively, another route involves analyzing biomarkers such as ethanol, total serum sialic acid, serum aminotransferases, α-hexosa- minidase, gamma-glutamyl transferase, and 5-hydroxytryptophan that have been linked to AUD [7–9]. Indole-3-lactic acid (ILA) dysregulation in the body has the potential to lead to alcohol addiction, making it a promising potential metabolite biomarker [10]. In serums from healthy individuals, the ILA level ranges from 0.51 to 0.92 μM [11]; however, no report is available for samples from AUD. At present, chromatographic techniques, including gas and liquid chromatography combined with mass spectrometry, are extensively utilized for ILA monitoring across various sample types due to their sensitivity and specifcity. However, these techniques often necessitate expensive instrumentation, specialized handling, and time-intensive sample preparations [12,13]. Given ILA’s electroactive nature, electro- chemistry presents a simpler, more reliable, and cost-effective alterna- tive. The integration of electroconductive materials, such as metallic nanoparticles, metal oxides, hybrids with other metals as well as * Corresponding author. School of Mechanical Engineering, Yeungnam University, Gyeongsan–38541, Republic of Korea. ** Corresponding author. School of Mechanical Engineering, Yeungnam University, Gyeongsan–38541, Republic of Korea. *** Corresponding author. School of Materials Science and Engineering, Yeungnam University, 280 Daehak-Ro, Gyeongsan, 38541, South Korea. **** Corresponding author. School of Materials Science and Engineering, Yeungnam University, 280 Daehak-Ro, Gyeongsan, 38541, South Korea. E-mail addresses: arghya@ynu.ac.kr (A.N. Banerjee), swj@yu.ac.kr (S.W. Joo), t.niyitanga@yu.ac.kr (T. Niyitanga), hkkim@ynu.ac.kr (H. Kim). 1 These authors contributed equally to this work. Contents lists available at ScienceDirect Talanta journal homepage: www.elsevier.com/locate/talanta https://doi.org/10.1016/j.talanta.2024.126919 Received 1 April 2024; Received in revised form 16 September 2024; Accepted 18 September 2024 Talanta 281 (2025) 126919 0039-9140/© 2024 Elsevier B.V. All rights are reserved, including those for text and data mining, AI training, and similar technologies.