Optical Detection of Lithium Therapeutic Levels in Porcine Interstitial Fluid Collected Using a Hollow Microneedle

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Pharmacology

Background:

• Bipolar disorder (BD) is a chronic, disabling mood disorder managed with lithium.
• Lithium has a narrow therapeutic range, necessitating regular monitoring due to toxicity risks.
• Current monitoring methods involve frequent blood tests, limiting point-of-care application.

Purpose of the Study:

• To investigate the feasibility of using dermal interstitial fluid (ISF) for lithium monitoring.
• To develop a minimally-invasive method for real-time lithium drug level assessment.

Main Methods:

• Utilized a microneedle-based sampling technique to extract ISF from porcine skin.
• Employed a colorimetric optical method with Quinizarin to detect lithium ion (Li+) concentrations in ISF.
• Analyzed spectral variations correlated with lithium concentrations in spiked ISF samples.

Main Results:

• Demonstrated that lithium concentration in ISF is proportional to serum levels.
• Observed spectral changes in ISF indicating the presence and concentration of lithium.
• Confirmed the feasibility of optical determination of therapeutic lithium concentrations in ISF.

Conclusions:

• Dermal interstitial fluid (ISF) is a viable biofluid for lithium monitoring.
• Microneedle-based sampling combined with optical detection offers a minimally-invasive approach for real-time lithium drug monitoring.
• This method holds potential for improved patient management of bipolar disorder.