Continuous-flow　microfluidic　biochips　are　gaining　increasing　attention　with　promising　applications　for　automatically　executing　various　laboratory　procedures　in　biology　and　biochemistry.　Biochips　with　distributed　channel-storage　architectures　enable　each　channel　to　switch　between　the　roles　of　transportation　and　storage.　Consequently,　fluid　transportation,　caching,　and　fetch　can　occur　concurrently　through　different　flow　paths.　When　two　dissimilar　types　of　fluidic　flows　occur　through　the　same　channels　in　a　time-interleaved　manner,　it　may　cause　contamination　to　the　latter　as　some　residues　of　the　former　flow　may　be　stuck　at　the　channel　wall　during　transportation.　To　remove　the　residues,　wash　operations　are　introduced　as　an　essential　step　to　avoid　incorrect　assay　outcomes.　However,　existing　work　has　been　considered　that　the　washing　capacity　of　a　buffer　fluid　is　unlimited.　In　the　actual　scenario,　a　fixed-volume　buffer　fluid　irrefutably　possesses　a　limited　washing　capacity,　which　can　be　successively　consumed　while　washing　away　residues　from　the　channels.　Hence,　capacity-aware　wash　scheme　is　a　basic　requirement　to　fulfil　the　dynamic　fluid　scheduling　and　channel　storage.　In　this　paper,　we　formulate　a　practical　wash　optimization　problem　for　microfluidic　biochips,　which　considers　the　requirements　of　dynamic　fluid　scheduling,　channel　storage,　as　well　as　washing　capacity　constraints　of　buffer　fluids　simultaneously,　and　present　an　efficient　design　flow　to　solve　this　problem　systematically.　Given　the　high-level　synthesis　result　of　a　biochemical　application　and　the　corresponding　component　placement　solution,　our　goal　is　to　complete　a　contamination-aware　flow-path　planning　with　short　flow-channel　length.　Meanwhile,　the　biochemical　application　can　be　executed　efficiently　and　correctly　with　an　optimized　capacityaware　wash　scheme.　Experimental　results　show　that　compared　to　a　state-of-the-art　washing　method,　the　proposed　method　achieves　an　average　reduction　of　26.1%,　43.1%,　and　34.1%　across　all　the　benchmarks　with　respect　to　the　total　channel　length,　total　wash　time,　and　execution　time　of　bioassays,　respectively.