Control of oxygen release from peroxides using polymers

Abstract

An important limitation in cell therapy for the regeneration of tissue is the initial lack of oxygen. After implantation of large 3D cell-seeded structures, cells die rather than contribute to tissue regenerating. Here we've tested oxygen-releasing materials to improve cell survival and growth after implantation. Calcium peroxide (CaO2) in a polymer matrix was used as source of oxygen. Two polymers were tested in order to slow down and extend the period of oxygen release, poly(D,L-lactic acid) and poly(lactic-co-glycolic acid). Compared to CaO2 particles, both releasing systems showed an initially higher and shorter oxygen release. Human mesenchymal stromal cells cultured on casted films of these oxygen-releasing composites required catalase to proliferate, indicating the production of cytotoxic hydrogen peroxide as intermediate. Poly(D,L-lactic acid) and poly(lactic-co-glycolic acid) are less suited for slowly oxygen-releasing materials. Catalase was able to reduce the cytotoxic effect of H2O2.

Applications of particulate oxygen-generating substances (POGS) in the bioartificial pancreas

“…The wash step prior to CPO incorporation in microbeads also prevented the burst release of oxygen from damaging islets, which has been previously shown to be a problem when using CPO as an oxygen source for tissue engineering applications. 44 …”

Breathing life into engineered tissues using oxygen-releasing biomaterials

“…As discussed, for a controlled rate of reaction, calcium peroxide can be incorporated into hydrophobic polymers. The controlled and sustained presence of oxygen is imperative for the first few weeks to promote cell differentiation and tissue healing 52,115 . The use of liquid peroxides (e.g., hydrogen peroxide) as oxygen carriers has also shown considerable potential in tissue engineering applications.…”

“…The main mechanism behind the oxygen release in these inorganic compounds is hydrolysis. When nano/microparticles of calcium, sodium, and magnesium peroxide interact with water, the particles undergo hydrolytic decomposition, as shown in the following equations [52][53][54] .…”

Controlled chemical synthesis of CaO2 particles coated with polyethylene glycol: characterization of crystallite size and oxygen release kinetics

“…13 Thus, two other methods have been proposed for the preparation of CaO 2 . In the rst method, CaO 2 is synthesized by the dehydration of CaO 2 $8H 2 O in water at 50 C and then vacuum drying of the ltered precipitate at 100 C. 9 The latter method consists of the reaction of dilute hydrogen peroxide with calcium oxide hydrate suspension 9 or the reaction of calcium salt solutions (chloride or nitrate) with ammonia and hydrogen peroxide [eqn (3) and (4)]. 9,14 CaCl 2 + H 2 O 2 / CaO 2 (hydrate) + 2HCl…”