A Hydrogel Microneedle Patch for Point‐of‐Care Testing Based on Skin Interstitial Fluid

Abstract

Skin interstitial fluid (ISF) holds great potential as a highly desirable sample resource for point‐of‐care testing (POCT), where the key is to effectively collect target biomarkers from ISF. Hydrogel microneedle patch has great promise for ISF extraction. However, it is challenging to recover target biomarkers from the extracted skin ISF in hydrogel microneedle patches in an easy‐administrated, fast, and bulky instrument‐free manner. Herein, a hydrogel microneedle patch made of polyvinyl alcohol (PVA) and chitosan (CS) for POCT based on the ISF is developed. The phase transition property of PVA/CS hydrogel makes the microneedles stiff when dry, which is beneficial to easily penetrate into skin. Meanwhile, the highly porous microstructure of hydrogel offers good swelling ability for extraction of ISF and the thermal degradation property of PVA makes it convenient to quickly and efficiently recover target biomarkers from microneedle patch. The capability of this platform for POCT applications is further demonstrated by successful detections of typical biomarkers collected from the mimetic skin and monitoring the glucose level in rabbit skins during a day. The developed hydrogel microneedle patch holds the advantages of extraction of skin ISF and recovery of biomarkers, thus presenting as a powerful platform for skin ISF‐based POCT applications.

Swellable Gelatin Methacryloyl Microneedles for Extraction of Interstitial Skin Fluid toward Minimally Invasive Monitoring of Urea

“…[ 19 ] However, only a few biopolymer‐based MNs systems for ISF sampling have been reported so far. [ 12,23–25 ] For instance, one study described the preparation of poly ( l ‐lactide) (PLLA) MNs coated with an alginate‐peptide nucleic acids hybrid material. These MNs patches, with 77 needles of 550 µm height, were tested to sample and detect nucleic acid biomarkers from ISF, being able to extract up to 6.5 µL of fluid in 2 min when immersed in PBS.…”

Smart Microneedles for Therapy and Diagnosis

“…For more efficient skin interstitial fluid extraction and cargo loading, polymer microneedles with highly porous and interconnected microstructures have been generated. To fabricate porous microneedles, various approaches have been adopted, such as adding pore-forming agents to the prepolymers [ 60 , 61 ] and changing the structure of the polymer chain [ 62 ]. In a recent study, Kim et al used a “water annealing” method to modulate the polymorphism of their silk fibroin microneedles [ 63 ].…”

Recent Advances in Antiinflammatory Material Design

“…Hydrogels made of natural compounds (hyaluronic acid, chitosan, alginate, gelatin, and silk) are often used for antiinflammatory drug delivery. Hydrogels are mostly used externally as wound dressings, [101] for surgical trauma healing [102] or for treatment of skin inflammation. [19] However some of them are used as coating of medical devices, [94] or as carriers for pancreatic islet delivery.…”

“…The results showed wet-adhesion ability and anti-inflammatory properties. [102] Lucca et al described the formulation of hydrogel containing copaiba oil, which is used as a popular anti-inflammatory medicine in the Amazonian forest region. Carbopol and hydroxyethyl cellulose hydrogels presented good stability, and antiinflammatory effect was observed in in vivo mouse edema model.…”