Preliminary Studies On Preparation Of Hemoglobin Nanocapsules

As one of the important parts of human body, blood performs the key roles in sustaining human life, such as carrying O2, CO2, nutrients and some metabolic products. As the result of the rapid growth of blood demand, the infection and spread of various diseases caused by traditional blood transfusion, the short storing time of crude blood and the limited donors, seeking for the safe and efficient blood substitutes has received a lot of attention throughout the world. The biodegradable nanocapsules containing hemoglobin (Hb) have the similar characteristics to natural red blood cells, therefore as the potential to become a new form of oxygen carrier.Two different methods were used in this study to prepare PLA nanocapsules containing Hb, which are used as blood substitutes. The discussion of the work is mainly divided into three parts:(1) Hemoglobin was extracted and purified from fresh bovine blood by centrifugation and heating treatment. The extracted Hb has a yield of 80% and purity of 98%, which is higher than the standard Hb from sigma.(2) A W/O/W double emulsion process was developed for preparation of PLA nanocapsules containing Hb. The factors such as concentration of PLA, the ultrasonic time, the ultrasonic intensity, organic solvents used and the impulse during the second emulsion which may influence the size, the encapsulation efficiency, and the loading efficiency of nanocapsules were investigated. The results showed that the encapsulation efficiency and the size of nanocapsules increased while the loading efficiency of nanocapsules decreased with the increase of PLA concentration; the longer the ultrasonic time and the stronger the ultrasonic intensity help to prepare the smaller nanocapsules, but the encapsulation and loading efficiency of nanocapsules decreased at the same time. The final product of nanocapsules obtained was small in size (650nm) with encapsulation efficiency of 15% and loading efficiency of 20%.(3) A nanoprecipitation technique was developed to prepare nanocapsules containing Hb. The factors such as concentration of PLA, temperature, the volume ratio of organic solution and aqueous solution, the stirring rate that may influence the size, the encapsulation efficiency and the loading efficiency were investigated. The results showed that the encapsulation efficiency and the size of nanocapsules increased while the loading efficiency of nanocapsules decreased with the increase of...