The present invention relates to a method of producing a polyomavirus or polyomavirus-derived virus-like particle (VLP) carrying on its surface at least one targeting molecule that binds to a cell of interest, the method comprising the step of contacting the polyomavirus or polyomavirus-derived VLP with (i) the targeting molecule, wherein the at least one targeting molecule is glycosylated with at least one glycosyl residue that is recognised by the polyomavirus or polyomavirus-derived VLP; or (ii) a first interaction molecule, wherein the first interaction molecule is glycosylated with at least one glycosyl residue that is recognised by the polyomavirus or polyomavirus-derived VLP; and the at least one targeting molecule, wherein the at least one targeting molecule is conjugated to a second interaction molecule capable of interacting with the first interaction molecule. The present invention further relates to a polyomavirus or polyomavirus-derived virus-like particle (VLP), wherein the virus or VLP carries on its surface at least one targeting molecule that binds to a cell of interest, as well as to a polyomavirus or polyomavirus-derived VLP obtained or obtainable by the method of the invention. Furthermore, the present invention relates to a composition comprising said polyomavirus or polyomavirus-derived VLP and to the use of the polyomavirus or polyomavirus-derived VLP of the invention or the composition of the invention for use as a medicament. The present invention further relates to a kit comprising the polyomavirus or polyomavirus-derived VLP or the composition of the invention.