Live spheroid formation recorded with light sheet-based fluorescence microscopy.

We provide a detailed protocol for a three-dimensional long-term live imaging of cellular spheroids with light sheet-based fluorescence microscopy. The protocol allows the recording of all phases of spheroid formation in three dimensions, including cell proliferation, aggregation, and compaction. We employ the human hepatic cell line HepaRG transfected with the fusion protein H2B-GFP, i.

DNA condensation by poly-L-lysine at the single molecule level: role of DNA concentration and polymer length.

Cationic poly(aminoacids) like poly-L-lysine (PLL) are known to be efficient in condensing plasmid DNA into compact nanostructures and have been used for in vitro and in vivo delivery of therapeutic DNA. Our study emphasizes on understanding the molecular mechanism of PLL-induced DNA condensation and the factors controlling it by visualization using Atomic Force Microscopy (AFM). Molecular morphologies were observed using AFM at increasing charge ratios as PLL interacts with DNA (Z+/Z- varied between 0.