Voltammetric bioassay of caffeine using sensor implant

Area of Science:

• Electrochemistry
• Biosensors
• Nanomaterials

Background:

• Voltammetric assays are crucial for detecting analytes like caffeine.
• Carbon nanotube paste electrodes (PE) offer good electrochemical properties.
• Enhancing the sensitivity and selectivity of these electrodes is an ongoing research area.

Purpose of the Study:

• To evaluate the performance of a DNA-modified carbon nanotube paste electrode (DPE) for caffeine detection.
• To compare the DPE's performance against an ordinary carbon nanotube paste electrode (PE).
• To explore the potential for in vivo caffeine analysis using the developed sensor.

Main Methods:

• Fabrication of a DNA-immobilized carbon nanotube paste electrode (DPE).
• Performance evaluation of DPE and PE using voltammetric techniques.
• Determination of working ranges, detection limits, and relative standard deviation under optimal conditions.

Main Results:

• The DPE exhibited significantly wider working ranges for caffeine (0.1–12 mg L⁻¹) compared to PE (30–230 mg L⁻¹).
• The DPE achieved a much lower detection limit (0.068 mg L⁻¹) than PE (9.94 mg L⁻¹).
• High precision was observed for the DPE, with a relative standard deviation of 0.064% at 5.0 mg L⁻¹ caffeine.

Conclusions:

• DNA immobilization onto carbon nanotube paste electrodes substantially improves caffeine detection performance.
• The DPE demonstrates superior sensitivity and a lower detection limit, making it suitable for trace caffeine analysis.
• The developed sensor holds promise for real-time in vivo caffeine monitoring in biological samples like leaf skin or brain cells.