A method of using fluid aspirates as vehicles for drug delivery by collecting a fluid aspirate such as synovial joint effusion, pleural effusion, pericardial effusion, or ascites from a patient and centrifuging the fluid aspirate to provide a supernatant and a sedimented material. The sedimented material can optionally be further purified. One or more factors such as cytokines, bone morphogenetic proteins (BMPs), pharmaceutical drugs and gene vectors are added to the sedimented material or supernatant, optionally also including a biologically compatible medium such as a bioabsorbable sponge, so as to provide a vehicle for the one or more factors for reintroducion into the patient.