Recruitment and Collection of Dermal Interstitial Fluid Using a Microneedle Patch

Area of Science:

• Biomarker discovery
• Microneedle technology
• Fluid dynamics

Background:

• Interstitial fluid (ISF) is a valuable source of biomarkers.
• Conventional methods for ISF collection are often invasive or complex.
• There is a need for simple, rapid, and cost-effective ISF harvesting techniques.

Purpose of the Study:

• To develop and optimize a minimally invasive microneedle (MN) patch for interstitial fluid (ISF) collection.
• To evaluate the efficiency and feasibility of the MN patch in vivo.
• To explore potential applications of MN-based ISF collection in diagnostics and research.

Main Methods:

• Development of a microneedle (MN) patch with 650 µm long needles.
• Application of the MN patch to rat skin in vivo at a specific angle.
• Optimization of ISF collection by varying skin pretreatment and delay times.
• Quantification of collected ISF volume and assessment of blood-free properties.

Main Results:

• The MN patch successfully collected >2 µL of blood-free ISF within 1 minute in rat skin.
• A brief skin pretreatment with MNs followed by a 5-minute delay significantly enhanced ISF collection.
• The optimized method was well-tolerated and demonstrated high efficiency.
• The mechanism for enhanced collection is hypothesized to involve increased skin hydration.

Conclusions:

• A minimally invasive microneedle patch provides a rapid, simple, and cost-effective method for collecting interstitial fluid (ISF).
• This technique offers a promising alternative to conventional methods for accessing ISF biomarkers.
• MN-based ISF collection has significant potential for advancing medical diagnostics and monitoring.