Negative pressure-controlled microneedle-microfluidic hybrid chip for painless in situ detection of ovalbumin-sIgE in skin interstitial fluid.

Allergen-specific immunoglobulin E (IgE) is a gold marker for the diagnosis of food allergy. The existing traditional diagnostic methods not only require blood collection and separation by professionals, but also are not friendly to pain-sensitive patients such as infants. Skin interstitial fluid (ISF) is highly similar to serum components, but its clinical value in the diagnosis of food allergy as an excellent sample for in situ painless detection is still unclear. To address the above issues, gel microneedles, functionalized paper-based modification and microfluidic technology were used to create an ISF integrated collection and detection device (ISF-ICD) for mouse ovalbumin (OVA)-sIgE. With the classical OVA-allergy model mice, the effects of ISF-ICD and traditional blistering method on collecting ISF were compared and analyzed, and the detection accuracy was compared with the traditional serum ELISA test results to further explore the relationship between ISF and serum OVA-sIgE content and changes. The results showed that the minimum detection limit of OVA-sIgE in ISF detected by the ISF-ICD was 0.064 ng/mL. The content of OVA-sIgE in ISF of OVA-allergic mice measured by ISF-ICD was similar to blister method. At 30 min after challenge, the OVA-sIgE content in ISF of OVA-allergic mice measured by different collection methods were 77.49 ± 9.11 ng/mL (ISF-ICD method) and 89.82 ± 11.26 ng/mL (blister method), respectively, which was about 1/15 of the serum OVA-sIgE content (1551.33 ± 30.51 ng/mL) measured by ELISA. In summary, the ISF-ICD has great significance to realize the screening and diagnosis of painless allergens for the prevention and treatment of food allergy.