Probing the Intracellular Delivery of Nanoparticles into Hard-to-Transfect Cells

Hard-to-transfect cells are cells that are known to present special difficulties in intracellular delivery of exogenous entities. However, the special transport behaviors underlying the special delivery problem in these cells have so far not been examined carefully. Here, we combine single-particle motion analysis, cell biology studies, and mathematical modeling to investigate nanoparticle transport in bone marrow-derived mesenchymal stem cells (BMSCs), a technologically important type of hard-to-transfect cells. Tat peptide-conjugated quantum dots (QDs-Tat) were used as the model nanoparticles. Two different yet complementary single-particle methods, namely, pair-correlation function and single-particle tracking, were conducted on the same cell samples and on the same viewing stage of a confocal microscope. Our results reveal significant differences in each individual step of transport of QDs-Tat in BMSCs vs a commonly used model cell line, HeLa cells. Single-particle motion analysis demonstrates that vesicle escape and cytoplasmic diffusion are dramatically more difficult in BMSCs than in HeLa cells. Cell biology studies show that BMSCs use different biological pathways for the cellular uptake, vesicular transport, and exocytosis of QDs-Tat than HeLa cells. A reaction-diffusion-advection model is employed to mathematically integrate the individual steps of cellular transport and can be used to predict and design nanoparticle delivery in BMSCs. This work provides dissective, quantitative, and mechanistic understandings of nanoparticle transport in BMSCs. The investigative methods described in this work can help to guide the tailored design of nanoparticle-based delivery in specific types and subtypes of hard-to-transfect cells.

Automated summary

This study investigates nanoparticle transport in hard-to-transfect cells using single-particle motion analysis, cell biology studies, and mathematical modeling. The researchers find significant differences in the transport of nanoparticles in bone marrow-derived mesenchymal stem cells (BMSCs) compared to HeLa cells. They also discover that BMSCs use different biological pathways for cellular uptake, vesicular transport, and exocytosis of nanoparticles compared to HeLa cells. A reaction-diffusion-advection model is used to mathematically integrate the steps of cellular transport and predict nanoparticle delivery in BMSCs. This work provides important insights into nanoparticle transport in hard-to-transfect cells and can guide the design of tailored nanoparticle-based delivery systems.