Fig. 4

Assessing therapeutic efficacy of nanoparticles. a A tumor-on-a-chip model to flow paclitaxel (PTX)-loaded nanoparticles across tumor spheroids held in hemispheric wells. Under flow conditions, the platform demonstrated increased treatment efficacy for high doses and lower flow rates. b A tumor-microenvironment-on-a-chip was used to assess the effect of doxorubicin-loaded hyaluronic acid nanoparticles (Dox-HANP). Nanoparticles accumulated more near MCF-7 cells breast cancer cells than MDA-MB-231 breast cancer cells. Scale bar, 50 µm. c A human colorectal tumor model was used to culture colon cancer cells in a circular central chamber and endothelial cells in the side channels. Introduction of gemcitabine (GEM)-loaded dendrimer nanoparticles showed a gradient dependent decay of cancer cell viability. Scale bars, 100 µm. d Novel shear-activated nanotherapeutics (SA-NTs) were flowed through a microfluidic device modelling a constricted vessel in the study of stenosis. High shear forces resulted in the SA-NTs breaking into individual nanoparticles, resulting in 10 times more nanoparticles after stenotic flow compared to normal flow. Greater accumulation was observed at endothelial cells post-stenosis than pre-stenosis. When SA-NTs were coated with a thrombolytic drug, the individual nanoparticles were able to accumulate at fibrin clots and dissolve them. Scale bars, 2 µm (top), 2 µm (middle left), 20 µm (middle right), 100 µm (bottom)