## 1 Introduction  
The oxygen concentration in the tissues of our body is regulated through biological processes and is important for embryo development, blood vessel formation, bone generation, stem cell function, and wound healing [1; 2]. During the regeneration of new tissues, a supply of oxygen is a prerequisite, since it is a key molecule required for maintenance and differentiation of cells and tissues prior to neo-microvessel formation. Oxygen promotes healing by preventing the infection of wounds, enhancing keratinocyte differentiation by inducing angiogenesis, and inducing collagen synthesis by facilitating re-epithelialization through the proliferation and migration of fibroblasts [3]. Unless oxygen is supplied within a certain amount of time, the function of the tissue will be compromised, and tissue neovascularization does not proceed in the correct manner [4]. Several studies have been performed regarding the promotion of the oxygen supply during tissue regeneration. [PERSON] et al. [5] reported that perfluorocarbon-loaded alginate spherical capsules that provide an oxygen-carrying matrix that can improve cell metabolism and survival. [PERSON] et al. [6] reported a high-pressure oxygen system, although the method warrants limited use as it requires special equipment, which is inconvenient and difficult to operate. Recently, [PERSON] et al reported oxygen-generating scaffolds where poly(lactic-co-glycolic acid) (PLGA) and calcium peroxide were combined together to overcome the limiting factors in the areas of infection, such as neovascularization, for healing large wounds. This scaffold fosters both cell survival and growth, and solves the problem of limited tissue size through the large surface area and pore structure of the 3D scaffold. However, the byproducts(salts) formed during metabolic processes change the pH of the tissue, cause metabolic reactions that can lead to tissue damage and also reduce the oxygen release rate [7; 8]. Therefore, the development of ideal oxygen generating system that can control the oxygen release remains a major focus. To address such limitations, this study developed a microsphere that can be used with a diverse range of pharmacological treatments. Briefly, hydrogen peroxide(H\({}_{2}\)O\({}_{2}\)) was encapsulated into PLGA (oxygen-releasing microsphere, ORM) allow the induced release of either H\({}_{2}\)O\({}_{2}\) as an antiseptic or the release of oxygen [9; 10]. Moreover, using this system, we could encapsulate various hydrophilic drugs these results suggest that this method can also be used as drug delivery systems (DDS) [11; 12]. H\({}_{2}\)O\({}_{2}\), as an oxygen supplier, is environmentally friendly since it can release oxygen over a long period of time without causing toxicity. PLGA microspheres with encapsulated H\({}_{2}\)O\({}_{2}\) have been shown to be effective as a therapeutic drug due to the sustained release effect in the body by implementing a DDS, reducing drug side effects, maximizing drug efficacy and efficacy [13]. A diverse array of wound dressings iscurrently being manufactured and commercialized including foam, sheet, and liquid dressings through a variety of development techniques. However, current technology is limited and still requires highly effective remedies. The ideal dressing provides a proper wetting environmentthe wound area and prevents the invasion of the bacteria. However, traditional wound healing methods use disinfectants until the wound is closed, cover the wound with gauze dressing, and do not address cell function. To overcome the disadvantages of conventional gauze dressings, a number of dressings have been developed and used that can improve cell activity or minimize scarring. However, as wound healing progresses, the condition of the wound changes, and the choice of dressing medication should be changed accordingly [14]. Currently available therapies for wound management increasingly rely on the use of wet dressings to achieve high levels of skin regeneration compared with the conventional gauze forms [15; 16; 17].