Controlled Release of Oxygen from PLGA-Alginate Layered Matrix and its In Vitro Characterization on the Viability of Muscle Cells Under Hypoxic Environment

Coagulative necrosis often occurs under hypoxic conditions, causing major limitation in the field of tissue engineering especially those dealing with larger tissues and organs. In this study, a comprehensive work has been performed in developing a tailor made design of a dual layered matrix that can produce oxygen to be utilized in tissue engineering application. Optimizations of protocol, ingredient and condition of the system were carried out specifically based on the responses observed from in vitro studies using L6 rat skeletal muscle cell as a candidate. Oxygen was generated from decomposition of encapsulated hydrogen peroxide. Poly (D,L)-lactide-co-glycolide (PLGA) with molecular weights of 90,000 and 110,000 gmol(-1) managed to secure good encapsulation of hydrogen peroxide for this application, while the best stirring time during the encapsulation was found to be 8 hours. The PLGA microspheres were coated with a secondary layer of alginate that was pre-grafted with calatase to form the dual layer system. This dual layered architecture has successfully controlled the release rate of oxygen at an optimum level for the survival of muscle cells under hypoxia condition. It was found that muscle cells have low tolerance limit towards the direct contact with hydrogen peroxide, however the cells maintained high viability within encapsulated hydrogen peroxide in the matrix system. It was observed that 4% of encapsulated hydrogen peroxide in the matrix system can produce efficient amount of oxygen at a controlled release manner to sustain the survival of muscle cells under hypoxic condition.