Multifunctional nano-drug carrier, preparation method thereof and drug-loading composition

The invention relates to a multifunctional nano-drug carrier, a preparation method thereof and a drug-loading composition, and belongs to the technical field of biomedical drug carriers and sustained-release drug carriers. The nano-drug carrier is formed by self-assembling a poly-seleno-amino acid amphiphilic block copolymer with a structure shown in the following formula, wherein n is more than or equal to 22 and less than or equal to 454, x is more than or equal to 2 and less than or equal to 50, y is more than or equal to 2 and less than or equal to 50, and n, x and y are integers. The nano-drug carrier provided by the invention can load drug molecules to prepare a sustained-release and controlled-release drug delivery system, and can be used for drug delivery in various modes, and theloaded drug can be released from the delivery system in a sustained-release and controlled-release mode according to needs, so that the drug delivery frequency is reduced, the treatment effect is improved, and the toxic and s