Lactate Dehydrogenase Electrochemical Sensing Using Electrodes with 3D Gold Nanostructures

As an enzyme, lactate dehydrogenase (LDH) can be found in almost all living cells, and it plays a vital role in energy production for cells to use. The abnormal levels of LDH may suggest tissue or organ damage, which may result from various diseases and injuries. LDH therefore has been used as one of the biomarkers or prognostic indicators for diseases and injuries of tissues or organs. Hence, it is paramount to monitor their levels in patients. Here, an electrochemical sensor with a nanostructured working electrode (nano-WE) for detecting LDH is reported. The nano-WE was fabricated by using an additive manufacturing process, resulting in arrayed nanopillars on the working electrode. Before detecting LDH, an on-chip process is implemented to modify the gold nano-WE with nickel hexacyanoferrate (NiHCF/Au) in situ for the first time. It has been found that this chip can detect LDH with a level as low as ∼1.0 U/L, which is among the best of previously reported screen-printed LDH sensors and bulk electrode-based LDH sensors. This chip has high specificity and can monitor LDH in serum samples spiked with a series of clinically relevant interference molecules. The stability tests of batch-fabricated chips indicate that the chips can provide consistent measurements for LDH in serum samples.