In vitrocellular uptake of fibroin microspheres and its dependency on the cell cycle stage

A Focus on "Bio" in Bio-Nanoscience: The Impact of Biological Factors on Nanomaterial Interactions

Bio-nanoscience research encompasses studies on the interactions of nanomaterials with biological structures or what is commonly referred to as the biointerface. Fundamental studies on the influence of nanomaterial properties, including size, shape, composition, and charge, on the interaction with the biointerface have been central in bio-nanoscience to assess nanomaterial efficacy and safety for a range of biomedical applications. However, the state of the cells, tissues, or biological models can also influence the behavior of nanomaterials at the biointerface and their intracellular processing. Focusing on the "bio" in bio-nano, this review discusses the impact of biological properties at the cellular, tissue, and whole organism level that influences nanomaterial behavior, including cell type, cell cycle, tumor physiology, and disease states. Understanding how the biological factors can be addressed or exploited to enhance nanomaterial accumulation and uptake can guide the design of better and suitable models to improve the outcomes of materials in nanomedicine.

Preparation and characterization of silk fibroin/oligochitosan nanoparticles for siRNA delivery

siRNA therapy offers hope treating diseases caused by genetic defects as well as viral infections and cancers, although it has been limited by the low stability of siRNA and its rapid degradation in the presence of nucleases as well as its low cellular uptake. In this study, oligochitosan (OC) combined with silk fibroin (SF) was formulated and proposed as a novel carrier for siRNA. The obtained SF/OC/siRNA nanoparticles (NPs) were characterized according to their physicochemical properties, such as their size, zeta potential, loading efficiency, stability, cytotoxicity, cellular uptake and transfection efficiency, and their properties were compared with those of OC polyplexes. The mean diameter of SF/OC/siRNA NPs was not significantly different compared to polyplexes, and the particle size ranged between 250 and 450 nm. Increased amounts of SF in NPs enhanced their loading efficiency, and NPs showed excellent stability in the presence of FBS and heparin compared with OC polyplexes. Additionally, MTT assays demonstrated that SF/OC/siRNA NPs had lower cytotoxicity. NPs showed better gene silencing with or without FBS, which could be attributed to increased loading efficiency, serum stability and cellular uptake. These properties suggest that SF/OC/siRNA NPs have a strong potential as gene carriers.

The role of the cell cycle in the cellular uptake of folate-modified poly(l-amino acid) micelles in a cell population

Nanoparticles are widely recognized as a vehicle for tumor-targeted therapies.

Growth, cell cycle progression, and morphology of 3T3 cells following fibroin microsphere ingestion

Cellular uptake of microspheres may cause physiological stress and toxicity. In this report, we investigated the effect of cellular uptake of fibroin microspheres on the growth, cell cycle progression, and morphology of 3T3 cells. The microspheres were prepared by physical cross-linking of fibroin molecules without any chemical modification. Fluorescent microspheres are comprised of fluorescein isothiocyanate-dextran core and fibroin shell. More than 90% of cells were determined to be fluorescence-positive following 24-h incubation with fluorescent microspheres (0.17 mg/mL). Microsphere localization in the cytoplasm was demonstrated using confocal and transmission electron microscopy. Cellular uptake of microspheres did not influence cellular viability, but microsphere concentrations above 0.1 mg/mL resulted in decreased cell proliferation. The proliferation inhibition was attributed to G2 /M phase delay in cell cycle progression and S-phase delay at higher microsphere concentrations (0.33 mg/mL). Although flow cytometry light-scattering data raised the possibility of morphological changes, Coulter counter analysis confirmed no significant size differences between cells incubated with and without microspheres. Accordingly, fibroin microspheres can be a potential vehicle for intracytoplasmic delivery of cargos, without affecting cell viability.

Scaffold-free formation of a millimeter-scale multicellular spheroid with an internal cavity from magnetically levitated 3T3 cells that ingested iron oxide-containing microspheres

This report describes fabrication of a millimeter-scale three-dimensional (3D) multicellular structure with a central cavity based on magnetic levitation of 3T3 cells that had ingested Fe3 O4 -containing microcapsules. Magnetically levitated cells initially formed a disc-shaped cell cluster at the air-medium interface and transformed into a spheroid (up to 2.8 mm in diameter) after 10-day incubation under a magnet. Hematoxylin-and-eosin-stained section revealed that an eosinophilic shell of cells enclosed a pale-staining core of the spheroid. Mitotic or elongated and aligned cells were found at the outer periphery of the shell, while Fe3 O4 deposits were distributed in the inner part of the shell. Surgical dissection indicated that the spheroid had a hollow interior filled with a fluid-state cell suspension. Accordingly, it was demonstrated that magnetically levitated 3T3 cells organized themselves into a tissue-like spheroid, resulting in core cell death. The spheroid can be used as a 3D tissue model and as building blocks that fused to form a more complicated structure.