Detachable Microneedles With Crosslinked Hyaluronic Acid as Superficial Skin Filler

Abstract

Crosslinking gives hyaluronic acid (HA) the ability to resist digestion by hyaluronidase; thus, crosslinked hyaluronic acid (cHA) is currently the most popular soft tissue filler. Clinically trained physicians usually administer cHA to the desired site via injections. Injection into the upper dermis and epidermis layers of the skin is challenging, and cHA with a low level of crosslinking is employed to prevent the uneven look, but it comes with a shorter lifetime. We demonstrate here the synthesis of cHA and its simultaneous fabrication into cHA-detachable microneedles (cHA-DDMNs). The cHA-DDMN patch allowed for the deposition of cHA into the ex vivo porcine skin in 1 min. The non-crosslinked HA placed into the ex vivo porcine skin spread out evenly within 30 min after it was applied. In contrast, the deposited cHA demonstrated prolonged localization in the tissue. Furthermore, we demonstrated the sustained release of curcumin delivered by cHA both in vitro and ex vivo. In rats, the administration of cHA-DDMNs to the skin did not cause skin irritation and led to a significant increase in dermal thickness and collagen deposition.