Answer to your question depends on what you intend to use it for i,e, the nature of your research. Is your project related to diagnostics or therapeutics? If it is the former, BSA may be a suitable alternative as long as you standardise it with human albumin. On the other hand, if you are working on a nanotherapeutic product, you may have to think twice because you may be creating new problems for yourself (eg. incompatibility, immune/complement activation etc).
If you are following the nanoparticle-based therapeutic procedure for in vivo applications, I do not recommend it; because it can lead to immunogenicity in the body serum.