Purification and biocompatibility of fermented hyaluronic acid for its applications to biomaterials.

Sungchul Choi,Insup Noh,Sekweon Kim,Su-Yeon Lee,Chan-Wha Kim,Woncheol Choi

doi:10.1186/2055-7124-18-6

Abstract

BackgroundHyaluronic acid (HA) is of importance due to its diverse applications in pharmaceuticals and medical devices such as dermal filler, adhesion barriers, carrier for cells and bioactive molecules as well as scaffold biomaterials for tissue engineering. Evaluations of purification and biocompatibility of HA are required for its applications to biomaterials.ResultsAfter synthesizing HA by fermentation of streptococcus zooepidemicus for 25 hr, extensively purification of the fermented broth was performed to remove impurities using a filtration process for insoluble components and cells, and diverse adsorbents for soluble impurities. Its in vitro biocompatibility has been evaluated by measurement of cell counting and assay of cell live and dead. 60% yield of white HA powder was obtained, having 15–17 dL/g intrinsic viscosity with a molecular weight of approximately 1,000 kDa. While low molecular weight impurities and insoluble impurities were successfully removed using a ultrafiltration membrane with 50 KDa molecular weight cut, endotoxins, high molecular weight proteins and nucleic acids were removed from the broth by employing adsorbents such as alumina and activated carbons. Alumina showed the best results for the removal of endotoxins, all of the activated carbons were very effective in the removal of high molecular weight proteins and nucleic acids. The purified HA solution showed excellent cell compatibility with no cell damages as observed by both measurement of cell proliferation and observation of cell viability.ConclusionsWe obtained high molecular weight HA with excellent biocompatibility as judged by both measurement of cell proliferation and viability, indicating high possibility of its applications to biomaterials.

Highlights

Hyaluronic acid (HA) is of importance due to its diverse applications in pharmaceuticals and medical devices such as dermal filler, adhesion barriers, carrier for cells and bioactive molecules as well as scaffold biomaterials for tissue engineering
While alumina was the best adsorbent for the removal of endotoxins, activated carbons such as Norit KBB, CN1, C Extra USP, A Supra EUR were very effective in the removal of high molecular weight proteins and nucleic acids
Among the employed activated carbons, the activated carbons in powders such as Norit C Extra USP and Norit A Supra EUR with a higher BET and neutral pH satisfied the criteria required for pharmaceuticals by EU

Summary

Introduction

Hyaluronic acid (HA) is of importance due to its diverse applications in pharmaceuticals and medical devices such as dermal filler, adhesion barriers, carrier for cells and bioactive molecules as well as scaffold biomaterials for tissue engineering. Purification of medium containing HA products has been achieved using a variety of different methods [9,10,11,12,13,14], including filtration and adsorption These methods normally result in the purification of HA with molecular weights ranging from 104 to 107 Da [14]. Various forms of purified HA have been used in different commercial products such as cosmetics [15], eye drops [16], food additives [17], medical devices [1], pharmaceutics [18,19,20], tissue engineering [21,22] and cell therapy [23]. HA is currently being investigated for use as a bioactive material for plastic fillers to eliminate facial wrinkles, a carrier to deliver stem cells, bioactive materials to treat specific diseases and a scaffold for tissue engineering of bone, cartilage, blood vessel and nerves [21,22]

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