Flavocytochrome b₂-Mediated Electroactive Nanoparticles for Developing Amperometric L-Lactate Biosensors

Area of Science:

• Biotechnology
• Electrochemistry
• Food Science

Background:

• L-Lactate monitoring is crucial for assessing food quality.
• Enzymes involved in L-Lactate metabolism are potential tools for biosensing.
• Flavocytochrome b2 (Fc*b*2) is a key enzyme in L-Lactate metabolism.

Purpose of the Study:

• To develop highly sensitive biosensors for L-Lactate determination.
• To utilize flavocytochrome b2 (Fc*b*2) as a bio-recognition element.
• To employ electroactive nanoparticles (NPs) for enzyme immobilization.

Main Methods:

• Isolation of Fc*b*2 from *Ogataea polymorpha* yeast.
• Immobilization of Fc*b*2 onto graphite electrodes using electroactive NPs.
• Utilizing redox nanomediators to enhance electron transfer.
• Fabrication of biosensors with co-immobilized Fc*b*2 and gold hexacyanoferrate.

Main Results:

• Confirmed direct electron transfer between reduced Fc*b*2 and graphite electrodes.
• Demonstrated amplified electrochemical communication using redox nanomediators.
• Achieved high sensitivity (up to 1436 A·M^-1·m^-2), fast response, and low detection limits.
• Validated a biosensor with 253 A·M^-1·m^-2 sensitivity for L-Lactate analysis in yogurt samples.
• Observed high correlation with established enzymatic-chemical photometric methods.

Conclusions:

• Developed highly sensitive and rapid biosensors for L-Lactate detection.
• Fc*b*2-mediated electroactive nanoparticle biosensors are effective for food quality analysis.
• These biosensors show significant potential for food control laboratories.