Lactic acid-stabilised albumin for microsphere formulation and biomedical coatings

Microspheres of ovalbumin (OVA) ranging from 1 to 15 mum were prepared by e mulsifying an aqueous solution of albumin in soya oil at room temperature t hen raising the temperature to 45 degreesC for 30 min, prior to harvesting of the microspheres. Production of OVA nanospheres with size less than 500 nm was achieved by desolvation from aqueous albumin solutions using acetone . In both cases, lactic acid was added to the starting albumin solution to stabilise the resulting particles. Utilisation of an endogenous substance a voids the use of chemical crosslinking agents such as glutaraldehyde and as sociated toxicological concerns. Protein coating of knitted Dacron vascular grafts was performed by impregnation of the textile structure with lactic acid-stabilised ovalbumin nanospheres thereby providing a surface potential ly resistant to blood platelet adhesion but conducive to endothelialisation , Protein release testing carried out in PBS at 37 degreesC revealed that a pproximately 60% of the original albumin coating was retained by the Dacron graft material after 4 days and remained at this level for upto 4 weeks. A part from the formulation of albumin microspheres for drug delivery, diagno stic applications and coating of biomedical textiles, the process of albumi n stabilisation using lactic acid may be usefully applied to improve protei n immobilisation on a wide range of biomaterial surfaces. (C) 2000 Elsevier Science Ltd. All rights reserved.