Skin biomechanics: Breaking the dermal barriers with microneedles

Abstract

Microneedles (μND) are promising devices that can be used to transport a wide variety of active compounds into the skin. To serve as an effective delivery system, μND must pierce the human stratum corneum (~10-20 μm), without breaking or buckling during penetration. In the current review, we discuss both the anatomical features and biomechanical properties of skin in order to understand the local environment and resistive forces relevant to μNDs insertion. Of particular importance are the factors that affect μND insertion, such as their geometry and material composition, as these can be manipulated in the design and development phase to optimise skin insertion. We review the research relevant to μND and how this interacts with skin properties. We have also reviewed the most commonly used skin drug diffusion modelling used to predict drug behaviour from μNDs, and discussed the current challenges faced by μNDs to enter clinical trials and provide positive clinical outcomes.

Chitosan Hydrogel Dressing Loaded with Adipose Mesenchymal Stem Cell-Derived Exosomes Promotes Skin Full-Thickness Wound Repair

“…When the weakly basic β-sodium glycerophosphate is added into the acidic chitosan solution, the mixture is adjusted into a neutral solution and then is transformed into a hydrogel. Compared with microneedles, another promising device to transport active drugs into the skin through breaking the dermal barriers, hydrogels are much more suitable for full thickness skin wound . We constructed an exosome/chitosan hydrogel composite by adding exosomes during the gelation process.…”

“…Compared with microneedles, another promising device to transport active drugs into the skin through breaking the dermal barriers, hydrogels are much more suitable for full thickness skin wound. 32 We constructed an exosome/chitosan hydrogel composite by adding exosomes during the gelation process. The cumulative release curve results showed that the composite hydrogel can degrade and release exosomes step by step in PBS solution (Figure 2F), indicating that the composite has the potential for sustained release of exosomes in the wound area.…”

Microneedle‐assisted transdermal delivery of nanoparticles: Recent insights and prospects

“…For its part, the “poke and release” approach is carried out using dissolving MAPs prepared via solvent‐casting or micro‐molding and made of different water‐soluble and biodegradable materials, like poly(vinyl pyrrolidone) (PVP), karaya gum, hyaluronic acid (HA), poly(methyl vinyl ether‐alt‐maleic acid) (PMVE‐MA), poly(vinyl alcohol) (PVA), carboxymethyl cellulose (CMC), chitosan and glycerol different sugars, etc., which include the drug or NPs of interest. After their insertion into the skin, they release the drug or NPs while they are getting dissolved by the interstitial skin fluids (Ali, Namjoshi, Benson, Kumeria, & Mohammed, 2022; Lee et al, 2019) (Figure 2).…”

“…MAPs are one of the most promising resources to improve drug absorption via the skin. They are minimally invasive devices that contain micrometric needle‐like projections which bypass the stratum corneum (SC), allowing the passage of large molecules and even proteins or NPs (Ali, Namjoshi, Benson, Kumeria, & Mohammed, 2022; Guillot et al, 2020). MAPs were initially developed as an attempt to overcome the usual drawbacks of hypodermic needles, but their applications are clearly a growing field in pharmaceutical research, as the number of scientific articles that include the keyword “microneedle” have been constantly rising after the appearance of dissolving or polymeric MAPs in the year 2000 (Chen et al, 2022).…”

Revolutionizing Wound Healing: Exploring Scarless Solutions through Drug Delivery Innovations

“…As the largest organ within the human body, the skin assumes a pivotal role in an array of activities and physiological functions, such as protecting against pathogens, toxic agents, sensing the external environment, and regulating body temperature. 1 However, due to its location on the outermost surface of the body and constant exposure to various challenges, the skin is prone to developing injuries, commonly known as wounds. 2 Various methods in tissue engineering and bioactive wound matrices have been employed to accelerate wound healing.…”