Biodegradable Polymer Nanosheets Incorporated with Zn-Containing Nanoparticles for Biomedical Applications

Abstract

So far, poly(L-lactic acid), PLLA nanosheets proved to be promising for wound healing. Such biodegradable materials are easy to prepare, bio-friendly, cost-effective, simple to apply and were shown to protect burn wounds and facilitate their healing. At the same time, certain metal ions are known to be essential for wound healing, which is why this study was motivated by the idea of incorporating PLLA nanosheets with Zn2+ ion containing nanoparticles. Upon being applied on wound, such polymer nanosheets should release Zn2+ ions, which is expected to improve wound healing. The work thus focused on preparing PLLA nanosheets embedded with several kinds of Zn-containing nanoparticles, their characterization and ion-release behavior. ZnCl2 and ZnO nanoparticles were chosen because of their different solubility in water, with the intention to see the dynamics of their Zn2+ ion release in liquid medium with pH around 7.4. Interestingly, the prepared PLLA nanosheets demonstrated quit similar ion release rates, reaching the maximum concentration after about 10 h. This finding implies that such polymer materials can be promising as they are expected to release ions within several hours after their application on skin.

PLLA Nanosheets for Wound Healing: Embedding with Iron-Ion-Containing Nanoparticles

“…Wounds are defined as damage or disturbance of normal anatomical structure and function of skin resulted from pathological processes that begin internally or externally [1,2]. Among different types of wounds, burns are known typically to need long-lasting and complex treatment to provide, support and accelerate their healing [3][4][5][6][7][8][9][10][11][12][13]. An ideal wound dressing used for their treatment should accelerate one or several stages of the healing processes, including the inflammatory phase, the migratory phase, the proliferative phase and the remodeling phase.…”

“…Nowadays, a variety of wound dressings are available and still widely used to treat such wounds [3][4][5][6][7][8][9][10]12,13]. However, even though the characteristics of "ideal" dressings for wound treatment are well known, such ultimate dressings are still difficult to realize within the same material [4][5][6][7][8][9][10][11][12][13]. It is still challenging, if ever possible, to realize an optimal combination of desired properties in one wrapping material, implying that new materials with improved characteristics are still highly anticipated.…”

“…It is still challenging, if ever possible, to realize an optimal combination of desired properties in one wrapping material, implying that new materials with improved characteristics are still highly anticipated. In parallel, incorporation of metal ions such as Mg, Zn, Fe and Cu is believed to be beneficial for efficient wound healing [2,4,5,11,[14][15][16]. However, very little progress has been achieved in this direction thus far.…”

“…Free-standing ultra-thin films (also known as nanosheets, NSs) of several biodegradable polymers (e.g., poly(L-lactic acid), PLLA) have been recently reported as efficient materials to cover burns, with the ability to adhere to any shape and protect wounds for days without the need for daily replacement [11,[17][18][19][20]. As wound wrapping materials, such NSs are: (1) inexpensive and relatively easy to prepare; (2) highly adhesive to virtually any surface with any shape; (3) permeable to water and air and biodegradable; (4) good as barriers for infection and dirt, and so on [11,[17][18][19][20]. Embedding such inexpensive and biodegradable polymer NSs with ions of crucial metals that can be released upon contacting the wound surface is therefore believed to enhance further their performance as burn-wound dressings [11,[17][18][19][20].…”

“…As wound wrapping materials, such NSs are: (1) inexpensive and relatively easy to prepare; (2) highly adhesive to virtually any surface with any shape; (3) permeable to water and air and biodegradable; (4) good as barriers for infection and dirt, and so on [11,[17][18][19][20]. Embedding such inexpensive and biodegradable polymer NSs with ions of crucial metals that can be released upon contacting the wound surface is therefore believed to enhance further their performance as burn-wound dressings [11,[17][18][19][20].…”