Research And Application Of Hyaluronic Acid Cosmetic Microneedles

The incessant increasing the demands of proficient cosmetics products which enhanced the integrity of the skin,without any antagonist effects.Wrinkle caused by facial expressions such as squinting,frowning or smiling can be treated by a dermatologist,using what are called injectable soft tissue "dermal fillers".Hyaluronic acid(HA)is one of the most commonly used injection-filled plastic material.We use HA to fabricate microneedles to take the place of the injections.Two categories of HA microneedles have been fabricated.One is non-crosslinked HA microneedles used to improve the skin moisture content and drug loading.We mainly study the preservation conditions(relative humidity is 0%-80%),conditions of use(force)and drug loading impact on microneedles performance.The other is cross-linked and non-crosslinked HA composite microneedles(HA_cHA-MNs).The study describes the fabrication process of cross-linked HA(cHA)and non-crosslinked HA,and mixture of cHA gel and non-crosslinked HA solution based microneedles(HA_cHA-MNs)for anti-ageing treatment.The 1,4-butanediol diglycidyl ether(BDDE)was used as a cross-linking agent to produce cHA gel.The cross-linking or modification degree was confirmed by using 1-H-NMR study.The different ratios of HA_cHA-MNs were subjected to mechanical properties using axial strength and also tested skin penetration ability against porcine cadaver skin to ascertain real time applicability.The data suggested that the increasing content of cHA gel particles decrease the mechanical properties of HA_cHA MNs.However,HA_cHA MNs have sufficient mechanical stability and penetration ability,which confirm from microscopic analysis.The in-vitro degradation profile and in-vivo epidermal expansion in mice were also carried out.The data suggested that the proportion of cHA particles in MNs increased and decreasing the rate of degradation of MNs.The prepared HA_cHA-MNs have prolonged effectiveness with high swelling retention time or epidermal expansion time in mice up to 6 days or more.Therefore,the prepared HA_cHA-MNs have safer and potentially able for anti-ageing treatment.In addition,we also designed mass-produced devices and packaging to conduct a preliminary exploration of the industrialization of cosmetic microneedles.