title: Microfluidic Buffer Exchange for Interference-free Micro/Nanoparticle Cell Engineering.
abstract: Engineering cells with active-ingredient-loaded micro/nanoparticles (NPs) is becoming an increasingly popular method to enhance native therapeutic properties, enable bio imaging and control cell phenotype. A critical yet inadequately addressed issue is the significant number of particles that remain unbound after cell labeling which cannot be readily removed by conventional centrifugation. This leads to an increase in bio imaging background noise and can impart transformative effects onto neighboring non-target cells. In this protocol, we present an inertial microfluidics-based buffer exchange strategy termed as Dean Flow Fractionation (DFF) to efficiently separate labeled cells from free NPs in a high throughput manner. The developed spiral microdevice facilitates continuous collection (>90% cell recovery) of purified cells (THP-1 and MSCs) suspended in new buffer solution, while achieving >95% depletion of unbound fluorescent dye or dye-loaded NPs (silica or PLGA). This single-step, size-based cell purification strategy enables high cell processing throughput (10(6) cells/min) and is highly useful for large-volume cell purification of micro/nanoparticle engineered cells to achieve interference-free clinical application.
authors: Lee Kong Chian School of Medicine, Nanyang Technological University.
authors: Hui Min
authors: HM
authors: Tay
authors: School of Chemical and Biomedical Engineering, Nanyang Technological University.
authors: David C
authors: DC
authors: Yeo
authors: School of Chemical and Biomedical Engineering, Nanyang Technological University.
authors: Christian
authors: C
authors: Wiraja
authors: School of Chemical and Biomedical Engineering, Nanyang Technological University; NTU-Northwestern Institute of Nanomedicine, Nanyang Technological University; cjxu@ntu.edu.sg.
authors: Chenjie
authors: C
authors: Xu
authors: Lee Kong Chian School of Medicine, Nanyang Technological University; hwhou@ntu.edu.sg.
authors: Han Wei
authors: HW
authors: Hou
mesh_terms: D002021:Buffers; D060846:Cell Engineering; D006801:Humans; D044085:Microfluidics; D053758:Nanoparticles; D012822:Silicon Dioxide
chemical_list: D002021:Buffers; D012822:Silicon Dioxide