Construction Of Mini Collagen And Its Application In The Healing Of Photodamaged Skin

The skin is the largest organ of the human body serving as the first line of defense between the human body and the external environment.Skin damage caused by prolonged exposure to ultraviolet radiation is considered one of the most severe public health issues of the 21 st century.Collagen is the primary component of the dermis of the skin,able to maintain the mechanical strength and structural integrity of tissues and organs.It actively participates in regulating various cellular activities and has garnered significant attention in the field of skin repair.Currently,collagen is mainly extracted from animal tissues.However,animal-derived triple helix collagen poses some problems such as immunogenicity,potential virus transmission and difficulty in penetrating the skin.The amino acid sequence of hydrolyzed collagen peptides is random and lacks the triple helix structure.Therefore,the construction of sequence-controlled collagen mimetic materials with superior biocompatibility and bioactivity has been a research hotspot in the field of dermatology.The amino acid sequence of collagen mimetic pepetides synthesized by solid phase is controllable,and there is no risk of virus transmission and immunogenicity.Thus,this thesis aims to design and construct a series of collagen mimetic pepetides(also named as Mini Collagen)that mimic the structure and function of natural collagen and to investigate their applications in the healing of photodamaged skin.The main contents are as follows:1.The construction of biomimetic materials that mimic the composition,structure,and function of natural collagen has significant importance in repairing damaged skin.We have designed and synthesized a series of highly active Mini Collagen with triple-helical structures and functional sequences.The designed Mini Collagen consists of the repeating Gly-Pro-Hyp sequence at the N-/C-terminals and the central functional sequence GFOGER derived from natural collagen.Mini Collagen displays a stable triple helix structure and exceptional biocompatibility.Only Mini Collagen that simultaneously possesses both the triple helical structure and functional sequences can promote fibroblast adhesion and migration.The Mini Collagen has the ability to rapidly recover the density,color,and moisture of UV-damaged skin.Animal experiment results have demonstrated that this Mini Collagen significantly stimulates collagen regeneration and effectively promotes the repair of photodamaged skin.It has potential application in the fields of tissue regeneration and dermatology.2.The barrier effect of the skin severely limits the transdermal delivery efficiency of functional macromolecules such as peptides and proteins.Therefore,the development of Mini Collagen with transdermal properties is crucial.We have for the first time constructed a series of arginine-containing transdermal Mini Collagen and selected a transdermal Mini Collagen with highly efficient transdermal properties and the ability to promote photodamaged skin repair,which improves the transdermal properties of Mini Collagen and the ability of skin repair.We designed transdermal Mini Collagen that exhibited a stable triple helical structure and excellent biocompatibility,which can promote the proliferation and adhesion of fibroblast.Transdermal Mini Collagen has good transcellular and transdermal ability,and can significantly promote the repair of acute UV-damaged skin,which is superior to that of Mini Collagen.The transdermal Mini Collagen constructed in this work demonstrates effective skin penetration and facilitates the self-repair of damaged skin.These findings establish a solid foundation for their future applications in the functional cosmetics industry.3.Collagen used in skin-care products is mainly extracted from animal tissues.However,animal-derived collagen poses challenges in terms of stability or biological activity.For the first time,we have developed a transdermal Mini Collagen repair dressing based on the second work.The transdermal Mini Collagen dressing exhibits excellent stability and does not aggregate over a wide range of temperatures.Animal studies have shown that compared to commercial collagen dressing products,the transdermal Mini Collagen dressing can rapidly recover skin density,color,and moisture and significantly promote the repair of acute UV-damaged skin.The experimental results of adverse reaction feedback,sensory evaluation,objective evaluation,and subjective evaluation of volunteers indicate that the transdermal Mini Collagen dressing has excellent user feelings and effectively improves skin condition.Therefore,our transdermal Mini Collagen dressing product will have a broad market prospect in the field of efficacy skin-care products.