Supplementary Information from An analytical approach for quantifying the influence of nanoparticle polydispersity on cellular delivered dose

Contains model and solution derivation, method of solution, experimental details and experimental data

Dynamic Flow Impacts Cell–Particle Interactions: Sedimentation and Particle Shape Effects

The interaction of engineered particles with biological systems determines their performance in biomedical applications. Although standard static cell cultures remain the norm for in vitro studies, modern models mimicking aspects of the dynamic in vivo environment have been developed. Herein, we investigate fundamental cell–particle interactions under dynamic flow conditions using a simple and self-contained device together with standard multiwell cell culture plates. We engineer two particle systems and evaluate their cell interactions under dynamic flow, and we compare the results to standard static cell cultures. We find substantial differences between static and dynamic flow conditions and attribute these to particle shape and sedimentation effects. These results demonstrate how standard static assays can be complemented by dynamic flow assays for a more comprehensive understanding of fundamental cell–particle interactions

Nanoengineering Particles through Template Assembly

The nanoengineering of particles is of interest for both fundamental and applied science. How particles are made substantially affects their properties and quality, and therefore usefulness. Disseminating current understanding of particle engineering can help facilitate the use of existing technologies, as well as guide future developments. Herein, we describe three methods used in our laboratory for the nanoengineering of particles, based on template assembly, and discuss important considerations for each. First, we describe the use of layer-by-layer assembly for depositing multilayered nanofilms on particle surfaces to generate core–shell particles and hollow capsules. Second, we detail the use of mesoporous silica templating for the engineering of porous polymer replica particles. Third, we describe how the coordination of phenolic compounds and metal ions can be used to fabricate thin films via metal–phenolic network formation on particle templates. We provide stepwise, easy-to-follow guides for each method and discuss commonly encountered challenges and obstacles, with considerations for how to alter these protocols to achieve desired particle properties. While we intend for these guides to be easily accessible to researchers new to particle engineering, we believe they can also provide useful insight to experienced researchers working in the field of engineering advanced particles

Nanoengineering Particles through Template Assembly

The nanoengineering of particles is of interest for both fundamental and applied science. How particles are made substantially affects their properties and quality, and therefore usefulness. Disseminating current understanding of particle engineering can help facilitate the use of existing technologies, as well as guide future developments. Herein, we describe three methods used in our laboratory for the nanoengineering of particles, based on template assembly, and discuss important considerations for each. First, we describe the use of layer-by-layer assembly for depositing multilayered nanofilms on particle surfaces to generate core–shell particles and hollow capsules. Second, we detail the use of mesoporous silica templating for the engineering of porous polymer replica particles. Third, we describe how the coordination of phenolic compounds and metal ions can be used to fabricate thin films via metal–phenolic network formation on particle templates. We provide stepwise, easy-to-follow guides for each method and discuss commonly encountered challenges and obstacles, with considerations for how to alter these protocols to achieve desired particle properties. While we intend for these guides to be easily accessible to researchers new to particle engineering, we believe they can also provide useful insight to experienced researchers working in the field of engineering advanced particles

Cellular Targeting of Bispecific Antibody-Functionalized Poly(ethylene glycol) Capsules: Do Shape and Size Matter?

In the present study, a capsule system that consists of a stealth carrier based on poly­(ethylene glycol) (PEG) and functionalized with bispecific antibodies (BsAbs) is introduced to examine the influence of the capsule shape and size on cellular targeting. Hollow spherical and rod-shaped PEG capsules with tunable aspect ratios (ARs) of 1, 7, and 18 were synthesized and subsequently functionalized with BsAbs that exhibit dual specificities to PEG and epidermal growth factor receptor (EGFR). Dosimetry (variation between the concentrations of capsules present and capsules that reach the cell surface) was controlled through “dynamic” incubation (i.e., continuously mixing the incubation medium). The results obtained were compared with those obtained from the “static” incubation experiments. Regardless of the incubation method and the capsule shape and size studied, BsAb-functionalized PEG capsules showed >90% specific cellular association to EGFR-positive human breast cancer cells MDA-MB-468 and negligible association with both control cell lines (EGFR negative Chinese hamster ovary cells CHO-K1 and murine macrophages RAW 264.7) after incubation for 5 h. When dosimetry was controlled and the dose concentration was normalized to the capsule surface area, the size or shape had a minimal influence on the cell association behavior of the capsules. However, different cellular internalization behaviors were observed, and the capsules with ARs 7 and 18 were, respectively, the least and most optimal shape for achieving high cell internalization under both dynamic and static conditions. Dynamic incubation showed a greater impact on the internalization of rod-shaped capsules (∼58–67% change) than on the spherical capsules (∼24–29% change). The BsAb-functionalized PEG capsules reported provide a versatile particle platform for the evaluation and comparison of cellular targeting performance of capsules with different sizes and shapes in vitro

A Framework to Account for Sedimentation and Diffusion in Particle–Cell Interactions

In vitro experiments provide a solid basis for understanding the interactions between particles and biological systems. An important confounding variable for these studies is the difference between the amount of particles administered and that which reaches the surface of cells. Here, we engineer a hydrogel-based nanoparticle system and combine in situ characterization techniques, 3D-printed cell cultures, and computational modeling to evaluate and study particle–cell interactions of advanced particle systems. The framework presented demonstrates how sedimentation and diffusion can explain differences in particle–cell association, and provides a means to account for these effects. Finally, using in silico modeling, we predict the proportion of particles that reaches the cell surface using common experimental conditions for a wide range of inorganic and organic micro- and nanoparticles. This work can assist in the understanding and control of sedimentation and diffusion when investigating cellular interactions of engineered particles