500 cells well after 24 hours the medium was changed and adipogenic or osteogenic or normal medium was added after 5 weeks when the aptamer isolated cells reached confluence the adipogenic and osteogenic staining procedure was started fresh human plasma was prepared by centrifugation 3000 g of whole blood for 20 min 8 nmol of the aptamer were incubated at 37 u00b0 c in a final volume of 0 5 ml of freshly prepared heparinized human plasma samples of 50 u03bcl were removed after 0 0 5 1 1 5 2 2 5 3 and 6 hours the reactions were terminated by adding of 10 u03bcl of loading buffer and subsequent storage on ice full length and digested oligonucleotides were separated on a 2 agarose gel and photodocumented porcine and human amscs were successfully isolated from bone marrow via gradient centrifugation expanded in a monolayer culture and evaluated for osteogenic differentiation potential spindle bipolar to polygonal fibroblastic cells were observed after 4 days of the first seeding the cells reached confluence after 12 days of culture on the first passage the cells showed a uniform monolayer the amscs cultured in osteogenic medium showed alp positive and von kossa positive calcium mineral precipitation after 8 days and 28 days the amsc cultured in adipogenic differentiation medium showed red oil staining while all the controls were negative fig1 a the surface marker staining showed that the attached cells were cd29 cd44 cd45 u2212 cd90 sla class i sla dq u2212 and sla dr u2212 fig1 b amscs derived from porcine and human bone marrow were used as the target for in vitro selection of aptamers from a random pool of dna molecules the starting library consisted of 79 mer single stranded dna molecules containing randomized 40 oligonucleotide inserts this.