Dd2 400 mhz nmr spectrometer

Fabrication of PLA-HPG in our laboratory has been previously described in detail (30 ). To surface modify these NPs to create PLA-HPG-Ad, 500 mg PLA-HPG was added to 40 mg 2',3'-Isopropylidene Adenosine-5'-carboxylic Acid and dissolved in 12 ml anhydrous DMF. The solution was dried with molecular sieve with 39 μl DIC and 6 mg DMAP added to the solution. The reaction was slowly stirred for 2 days. To purify, the solution was centrifuged at 10,000 rpm for 10 min. The resulting supernatant was collected and added into a large amount of cold diethyl ether to precipitate the polymer. The polymer precipitate was collected by centrifugation at 10,000 rpm for 10 min. The resultant polymer was dissolved in 3 ml DCM/TFA mixture (DCM:TFA = 2:1) and the reaction was shaken at room temperature for 2 h. The resulting solution was added into a large amount of cold diethyl ether and the polymer was collected by centrifugation at 10,000 rpm for 10 min. The polymer was further purified by redissolving in DCM and precipitating in diethyl ether. The purified polymer was dried under vacuum for 2 days. To determine conjugation of Ad to PLA-HPG, PLA-HPG-Ad and PLA-HPG polymers were dissolved in DMSO-d6 and 1H NMR analysis was carried out on an Agilent DD2 400 MHz NMR Spectrometer. The average number of Ad per PLA was estimated based on the integral of peak 4 (6.35ppm) and peak 5 (5.18ppm)