Scalable mesenchymal stem cell enrichment from bone marrow aspirate using deterministic lateral displacement (DLD) microfluidic sorting
Tan Kwan Zen, Nicholas; Zeming, Kerwin Kwek; Teo, Kim Leng; Loberas, Mavis; Lee, Jialing; Goh, Chin Ren; Yang, Da Hou; Oh, Steve; Hui Hoi Po, James; Cool, Simon M.; Hou, Han Wei; Han, Jongyoon
The growing interest in regenerative medicine has opened new avenues for novel cell therapies using stem cells. Bone marrow aspirate (BMA) is an important source of stromal mesenchymal stem cells (MSCs). Conventional MSC harvesting from BMA relies on archaic centrifugation methods, often leading to poor yield due to osmotic stress, high centrifugation force, convoluted workflow, and long experimental time (∼2–3 hours). To address these issues, we have developed a scalable microfluidic technology based on deterministic lateral displacement (DLD) for MSC isolation. This passive, label-free cell sorting method capitalizes on the morphological differences between MSCs and blood cells (platelets and RBCs) for effective separation using an inverted L-shaped pillar array. To improve throughput, we developed a novel multi-chip DLD system that can process 2.5 mL of raw BMA in 20 ± 5 minutes, achieving a 2-fold increase in MSC recovery compared to centrifugation methods. Taken together, we envision that the developed DLD platform will enable fast and efficient isolation of MSCs from BMA for effective downstream cell therapy in clinical settings.
Scalable mesenchymal stem cell enrichment from bone marrow aspirate using deterministic lateral displacement (DLD) microfluidic sorting
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A large-area lithium metal–carbon nanotube film for precise contact prelithiation in lithium-ion batteries
A large-area lithium metal–carbon nanotube film for precise contact prelithiation in lithium-ion batteries
Wang, Chao; Yang, Fangzhou; Wan, Wang; Wang, Shihe; Zhang, Yongyi; Huang, Yunhui; Li, Ju
Prelithiation is a method to improve the energy density and cycle life of lithium-ion batteries, and contact prelithiation of the graphite anode using thin lithium foil is a promising technique. However, producing thin lithium foil below 5 μm is extremely challenging, making it difficult to achieve precise prelithiation with lithium metal. Additionally, pure thin Li foil suffers from drawbacks such as low lithium utilization, debris formation, and scalability issues. To address these challenges, we developed a straightforward doctor blade method to cast molten lithium onto a carbon nanotube (CNT) film, resulting in a thin and ultra-light Li-CNT film. The increasing lithiophilicity of the CNT film induced by lithiation enables the uniform casting of molten lithium onto its surface. The method enables adjustable lithium capacities ranging from 0.1 to 1.12 mA h cm−2 or higher by controlling the amount of cast lithium. The Li-CNT films show high specific capacities and nearly 100% lithium utilization owing to their exceptional conductive network, porous structure, and electrolyte-philic nature, which facilitates the efficient transport of both electrons and lithium ions. To achieve prelithiation of the graphite anode when paired with commercial LFP electrodes of ∼3.3 mA h cm−2, our Li-CNT film significantly enhances the initial Coulombic efficiency of the LFP||Gr full cell from 89% to 100%, fully compensating for the initial loss of active lithium ions caused by solid electrolyte interface formation. Furthermore, the Li-CNT film has superior mechanical properties, positioning it as a viable candidate for practical applications in lithium-ion batteries.
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Tuning reduction conditions to understand and control Ni exsolution from Sr0.8La0.1Ca0.1Ti0.94Ni0.06O3−δ
Tuning reduction conditions to understand and control Ni exsolution from Sr0.8La0.1Ca0.1Ti0.94Ni0.06O3−δ
O'Leary, Willis; Giordano, Livia; Rupp, Jennifer L. M.
Ceramic-supported metal catalysts formed by exsolution of metal nanoparticles from perovskites are promising materials for energy and chemical conversion applications. However, our incomplete understanding of the exsolution mechanism presents a roadblock to engineering exsolution nanoparticle properties. We investigated the influence of reduction conditions on the properties of Ni nanoparticles exsolved on the fracture surfaces of Sr0.8La0.1Ca0.1Ti0.94Ni0.06O3−δ. We first carried out exsolution at 25 different temperatures and oxygen chemical potentials. We found that reduction at lower temperatures and moderate oxygen chemical potentials produced more numerous, smaller nanoparticles. We then fit our data to a LaMer nucleation model where the number of nanoparticles formed depends on Ni surface segregation, reduction of Ni-rich surfaces, and nanoparticle growth. Finally, we demonstrated prediction of the energetics of these processes with density functional theory calculations. Our experiments and modelling build understanding of the exsolution mechanism and are a step towards computational design of supported metal catalysts made via exsolution.
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Particle focusing in a wavy channel
Particle focusing in a wavy channel
Mao, Xinyu; Bischofberger, Irmgard; Hosoi, A.E.
It is known that inertial lift forces can lead to particle focusing in channel flows; yet oscillatory straining effects have also been suggested as a mechanism for particle focusing in wavy channels. To explore the synergy between these two mechanisms, we analytically and experimentally investigate the focusing behaviour of rigid neutrally buoyant particles in a wavy channel. We decompose the particle-free channel flow into a primary Poiseuille flow and secondary eddies induced by the waviness. We calculate the perturbation of the particle on the particle-free flow and the resulting lateral lift force exerted on the particle using the method of matched asymptotic expansions. This yields a zeroth-order lift force arising from the Poiseuille flow and a first-order lift force due to the waviness of the channel. We further incorporate the inertial lift force into the Maxey–Riley equation and simulate particle trajectories in wavy channels. The interactions between the zeroth-order lift force and the particle-free flow largely determine the focusing locations. Experiments in wavy channels with varying amplitudes at channel Reynolds numbers ranging from 5 to 250 are consistent with the predictions of the focusing locations, which are mainly governed by the channel Reynolds number as well as the competition between the inertial lift and the oscillatory straining effects.
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