Phospholipid-functionalized gold electrode for cellular membrane interface studies - interactions between DMPC...

Area of Science:

• Electrochemistry
• Biosensing
• Surface Science

Background:

• Human cystatin C (hCC) is a protein implicated in various physiological and pathological processes.
• Mutations in hCC, such as V57G, can alter its function and interactions.
• Developing sensitive detection methods for hCC mutants is crucial for understanding their roles.

Purpose of the Study:

• To investigate the electrochemical interactions between the V57G mutant of human cystatin C (hCC V57G) and a membrane bilayer.
• To develop a highly sensitive electrochemical sensor for hCC V57G detection.
• To characterize the surface properties and interactions using electrochemical and surface analysis techniques.

Main Methods:

• Electrode modification with 6-mercaptohexan-1-ol (MCH) and 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) to create a membrane mimetic.
• Electrochemical analysis using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) with Fe(CN)₆^3-/4- redox probe.
• Surface characterization using contact angle measurements and X-ray photoelectron spectroscopy (XPS).

Main Results:

• The fabricated electrode demonstrated high sensitivity to hCC V57G, detecting concentrations as low as 1 x 10^-14 M.
• Electrochemical measurements showed minimal changes at higher hCC V57G concentrations, indicating saturation or stable surface coverage.
• Contact angle and XPS analyses confirmed the successful immobilization of hCC V57G and provided insights into surface interactions.

Conclusions:

• A novel electrochemical sensor based on a DMPC-functionalized gold electrode is capable of highly sensitive detection of hCC V57G.
• The sensor's sensitivity is attributed to specific interactions between hCC V57G and the membrane mimetic.
• This approach offers a promising platform for the electrochemical detection of cystatin C variants.