Rationally Designed LaWO₄ Nanoflakes for the Simultaneous Electrochemical Detection of Valine and Leucine in Serum of Prostate Cancer Patients

Prostate cancer is a leading cause of mortality worldwide. The PSA test diagnoses the prostate-specific antigen (PSA) (prostate cancer biomarker); however, the false-positive and false-negative results impact the reliability of tests. The amino acid level in prostate cancer is considered a potential diagnostic biomarker and has a role in cancer metastasis. Electrochemical sensing of Leucine and valine in prostate cancer patients can enhance the accuracy of prostate cancer detection. Lanthanum tungstate NFs were characterized by Fourier transmission infrared spectroscopy (FTIR), ultraviolet spectroscopy (UV), X-ray diffraction spectroscopy (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), EDX, and atomic force microscopy (AFM). After characterization, lanthanum tungstate nanoflakes are fabricated and used to detect leucine and valine in this study. LaWO
₄
NFs exhibit linearity for leucine and valine with LODs as
$2.2 ~\mu \text{M}$
(6.8 ng/mL) and
$2.0 ~\mu \text{M}$
(2.3 ng/mL), respectively. Moreover, the synthesized sensing material is selective for leucine and valine detection from serum samples of prostate cancer patients.