Provided are compositions for long-term maintenance of functional hepatocytes in culture, a method for improved maintenance of functional hepatocytes in vitro, and functional hepatocytes cultures according to the methods. The culture compositions include at least: one activator of adenylate cyclase, one TGFβ inhibitor, one Notch inhibitor, one Wnt inhibitor, and/or one BMP inhibitor. The combinations of compounds are added to any hepatocyte cell culture medium in an effective amount to maintain functional hepatocyte function in vitro, long term. The hepatocytes can be used for in vitro drug research and to model liver disease.

Methods and compositions are provided for the analysis of rare cells or other biological entities in a population, by contacting the population with a labeling nanoparticle comprising a VLP conjugated to a light emitting moiety and a specific binding moiety, then detecting the presence of bound nanoparticle by light emission.

Provided are compositions for long-term maintenance of functional hepatocytes in culture, a method for improved maintenance of functional hepatocytes in vitro, and functional hepatocytes cultures according to the methods. The culture compositions include at least: one activator of adenylate cyclase, one TGFinhibitor, one Notch inhibitor, one Wnt inhibitor, and/or one BMP inhibitor. The combinations of compounds are added to any hepatocyte cell culture medium in an effective amount to maintain functional hepatocyte function in vitro, long term. The hepatocytes can be used for in vitro drug research and to model liver disease.