Target cell specific delivery system of anti-cancer drugs by Bio-nano particles.

(1)为了证明由乙肝病毒包膜蛋白组成的中空纳米粒(生物纳米粒)是一种有效的药物肝给药载体，将一种模型荧光化合物钙黄绿素(Calcein)包裹在生物纳米粒中，并将其添加到各种细胞系的培养中。以钙黄绿素为模型，建立了钙黄绿素生物纳米粒包封量的测定体系，并以此为模型寻找钙黄绿素生物纳米粒的最佳电穿孔条件。(3)构建了以8个半胱氨酸残基(M8颗粒)为取代基团的突变型生物纳米粒，以提高药物包封率。(4)利用(2)中确定的条件，将抗癌药物紫杉醇包埋在(3)中所述的改进型生物纳米颗粒(M8颗粒)中，并将其添加到不同细胞系的培养中。生物纳米颗粒包裹的抗癌药物对HepG2细胞的生长抑制作用是药物本身的5倍，这表明生物纳米颗粒作为人肝脏特异性药物传递载体的有效性。

(1)To show that the hollow nanoparticle composed of the envelope protein of hepatitis B virus (Bio-nano particle) is an efficient delivery vector of pharmaceutical drugs to human liver, a model fluorescent compound (calcein) was enclosed in Bio-nanoparticles and added to the cultures of various cell lines. After 1-day culture, calcein was detected specifically in human hepatoma cells (HepG2) but not in cells derived from other tissues.(2)The system for measuring the amount of drugs encapsulated in Bio-nanoparticles was established by using calcein as a model, and used to find the optimum conditions of electroporation for encapsulation of calcein.(3)A mutant bio-nanoparticle with substitutions of 8 cysteine residues (M8 particle) was constructed to increase the efficiency of drug-encapsulation, since these cysteine residues frequently formed false and undesirable intramolecular disulfide bridges that prevent the drug influx into the particles. The amount of calcein encapsulated into the resultant M8 particle was 2.5-fold more than that into wild-type Bio-nanoparticle.(4)By using the conditions determined in (2), an anti-cancer drug of pacritaxel was encapsulated into the improved version of Bio-nanoparticle (M8 particle) described in (3) and added to the cultures of various cell lines. The anti-cancer drug encapsulated in Bio-nanoiparticles inhibited the growth of HepG2 cells 5-times more efficiently than the drug itself.Thus, these results showed the usefulness of Bio-nanoparticle as a delivery vector specific to human liver for pharmaceutical drugs.