From Spin to Star: Ultrafast Dual‐Gradient Centrifugal Microfluidics for Scalable High‐Throughput and Combinatorial Nanomaterial Synthesis

Abstract This study introduces the DC‐UltraScreen‐90, a novel dual‐gradient centrifugal microfluidic device for ultrafast, high‐throughput nanomaterials screening in 90 micro‐reactors. Using silver nanoparticle (AgNP) synthesis as a model, this device incorporates a “siphon‐based aliquoting” microstructure, enabling all precursor solutions – hydroxylamine (HA), sodium citrate (NaCt), sodium hydroxide (NaOH), and silver nitrate (AgNO 3 ) – to be loaded with a single pipetting step per solution. Centrifugation drives these solutions into 540 aliquoting microchambers, which are then mixed and distributed into 90 reaction chambers. A “dual‐gradient” structure automates the generation of HA and NaCt concentration gradients by pairing reactant microchambers with diluent chambers, achieving equal final volumes with varying concentrations. This process yields diverse AgNP morphologies, with HA primarily influencing NP formation and NaCt governing morphological tuning and spike length of Ag nanostars. The entire workflow, from solution loading to reaction, is achieved under 3 min, demonstrating exceptional efficiency for HTP screening in nanomaterial synthesis.