An interstitial fluid-like NICHE-chip for neural stem cell niche modeling and nanoscale neurotrophic delivery.

Neural stem cells (NSCs) reside in anatomically confined niches, where three-dimensional (3D) geometry and interstitial fluid (ISF) flow collectively regulate NSC behavior. However, in vitro platforms that simultaneously recapitulate size-controlled 3D architecture, ISF-like dynamics, and nanoscale therapeutic delivery remain limited. Here, we present a 3D printing-based platform with multi-sized microwells, termed the Neural-Inspired Culture for a Hydrodynamic Environment (NICHE)-chip, which incorporates an osmosis-driven flow system to generate ISF-like flow. The NICHE-chip enabled stable formation of uniform human neural stem cell (hNSC) neurospheres across defined microwell sizes. Under ISF-like flow, hNSC neurospheres showed enhanced viability, reduced apoptosis, and increased self-renewal and differentiation marker expression, particularly in 100 μm microwells. ISF-like flow also promoted laminin-rich extracellular matrix (ECM) deposition and cell-cell interactions, suggesting niche-like remodeling of the 3D microenvironment. In the ISF-integrated 100 μm neurosphere model, amyloid-β (Aβ) was introduced to establish an Alzheimer's disease (AD)-like neurotoxicity model, which was then used to evaluate nanoparticle-mediated neurotrophic factor delivery using brain-derived neurotrophic factor (BDNF)-loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles. BDNF-loaded PLGA nanoparticles (BDNF-NPs) enabled sustained BDNF delivery, attenuated Aβ-induced neuronal marker loss, and counter-regulated a subset of Aβ-induced transcriptional alterations associated with neuroprotection. Overall, the NICHE-chip provides an ISF-integrated 3D neurosphere culture platform for NSC niche modeling, AD-like neurotoxicity assessment, and nanoscale neurotrophic factor delivery.