Synthesis of AMS-maleimide AMS-maleimide was synthesized according to a previously reported 2-step procedure (Figure ). 6-MHA was first chlorinated by oxalyl chloride to yield 6-maleimidohexanoyl chloride (6-MHC) . Then, amylomaize starch, dissolved in DMAc/LiCl, was esterified by 6-MHC. AMSmaleimide was precipitated in ethanol, filtered, washed, vacuum-dried and finally recovered as a yellowish powder. The detailed procedure for both steps can be found in the Supporting Information (SI).