Bio-nanocapsule (BNC) is a nano-size capsule produced by Biotechnology. BNC is a hollow nano-particle expressing L-type surface protein of Hepatitis B virus (HBV). BNC is produced by yeasts whose gene was introduced by HBV’s L-protein gene. The surface protein, named L-protein, which resides in lipid membrane, has ability to specifically recognize human hepatic cells and to introduce the content of BNC into the cytoplasm. The L-protein is consisted of S region, pre-S2 region and pre-S1 region, and the S-region is known to have a membrane-penetration motif.

Advantages of Bio-nanopcapsule

　Usage BNC as drug delivery system gives your several advantages as follows;

１．	BNC is very small (about 70 nm diameter) hollow particle. (The size differs slightly depending on the types) .
２．	BNC recognizes human hepatic cells specifically (BNC types recognizing non-hepatic cells have also been developed).
３．	BNC has ability to actively introduce encapsulated substances into cells.
４．	BNC has ability to fuse with lipid membranes.
５．	BNC-liposome complex has ability to escape from reticulo-endothelial system as seen in PEG-modified liposomes.
６．	BNC is safe because it contains no virus-derived genomes.
７．	A similar particle to BNC is extensively used as HBV vaccine world wide.

Types of Bio-nanopcapsule

　The original BNC specifically recognizes human hepatic cells, but we have developed other types of BNC that recognize other cell types. Currently following four types are available.

　　　　　　　　　　　　　　　　　　　　　　　 　　　　　　　　　　　　　　　　　　　　　　　　

BNC-L：	The original BNC which expresses L-protein whose amino acid sequence is identical with that expressed HBV surface. BNC-L specifically recognizes human hepatic cells.
BNC-ST：	This is the BNC whose L-protein is modified so that antigenecity of L-protein is extremely low, and thus ideal for medical use. BNC-ST, like BNC-L, binds human hepatic cells.
BNC-ZZ：	A part of amino acid sequence of L-protein is exchanged to ZZ-tag sequence of Protein A which is known to be the binding domain of Fc domain of antibodies. BNC-ZZ can, thus, easily bind antibodies, and recognize cells that are recognized by attached antibodies.
BNC-Bio：	This is a biotynized BNC. Through Biotin-avidin reaction, many targeting molecules, such as peptides, sugar chains, and lectins, can be attached to BNC. Thus BNC-Bio can recognize many cell types that is recognized by the attached targeting molecules.
BNC-X,-XT：	HBsAg with high antigen activities. These are made from BNC-L.
Special BNC：	By modifying amino acids sequence of Pre-S1 region, non-hepatic cell-tageting BNCs can also be produced (special order).