Enveloped virus vectors are described which comprise a cellular virus receptor protein and which are capable of fusing with a cell which comprises a viral envelope protein to which the cellular virus receptor protein is cognate. Enveloped virus vectors comprising a plurality of cellular virus receptor proteins are also described. Methods for making the enveloped virus vectors are described, as are methods of using the enveloped virus vectors. The invention further relates to a lipoparticle comprising a membrane spanning protein, and the lipoparticle can be attached to a sensor surface. The invention relates to methods of producing and using the lipoparticle to, inter alia, assess protein binding interactions.