Computational, microscale thermophoresis and electrochemical study of a hepta-peptide for a simple, sensitive electrochemical biosensor for PSA

• Published in: Microchemical journal Vol. 206; p. 111386
• Main Authors: Alake, John, Mahlalela, Mavela Cleopus, Mohite, Sachin, Partap, Sangh, Gafar, Mohammed A., Adu, Darko Kwabena, Ike, Blessing Wisdom, Chauhan, Ruchika, Nate, Zondi, Karpoormath, Rajshekhar
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.11.2024
• Subjects: Biosensor; Differential pulse voltammetry; Microscale thermophoresis; Peptide; Prostate cancer; Prostate-specific antigen; Prostate-specific antigen; Prostate cancer; Peptide; Biosensor; Differential pulse voltammetry; Microscale thermophoresis
• ISSN: 0026-265X
• DOI: 10.1016/j.microc.2024.111386

[Display omitted] •Computational study revealed strong affinity between petite SSKYQSL and PSA.•Microscale thermophoresis confirmed the affinity with a low Kd value of 17.4 nM.•The peptide immunosensor revealed a 0.1 pg/mL detection limit for PSA.•The peptide immunosensor showed an average of 102 % (RSD = 3.82 %) recovery in serum. Studies indicate a potential 108 % increase in incidence and 112 % in mortality rate of prostate cancer in Sub-Saharan Africa by 2040. Electrochemical sensors show promise as the best alternative analytical tool for detecting cancer markers with simple operation and easy quantification. In recent years, researchers have been focused towards simple stable and cost-effective biomolecules that are easier to produce. The peptide sequence SSKYQSL’s with excellent affinity to Prostate-specific antigen (PSA) has been exploited for targeted drug delivery. Herein, we take the potential use of the peptide further by proposing a simple but robust electrochemical immunosensor using the peptide as the bioreceptor. We report the first molecular docking of the peptide to PSA to gain more insight into the chemical interaction between the sequence and PSA. Also, we validated the binding interaction and quantified the binding affinity between the two molecules using microscale thermophoresis for the first time. The peptide was then immobilised on a multiwalled carbon nanotube via EDC-NHS conjugation chemistry for a simple, sensitive electrochemical sensor to quantify PSA in serum. From the computational study, the peptide was observed to engage in different molecular interactions with PSA, including conventional and carbon-hydrogen bonds, van der Waals, pi-alkyl, pi-pi stacked, salt bridge and attractive charge interaction. The affinity was confirmed with microscale thermophoresis, demonstrating good binding interactions between the peptide and PSA with a low Kd value of 17.4 nM. The fabricated immunosensor was highly sensitive to PSA with a 0.1 pg/mL detection limit and a linear range of 1.0 µg/mL to 1.0 pg/mL with an average of 102 % recovery in serum.