Six-well plate-based colony-forming efficacy assay and Co-Culture application to assess toxicity of metal oxide nanoparticles

Targeted delivery and apoptosis induction of CDK-4/6 inhibitor loaded folic acid decorated lipid-polymer hybrid nanoparticles in breast cancer cells

Targeted drug delivery is an advanced approach for active targeting of tumor that can enhance the concentration of the drug at the site of action and reduce the off-target toxicity and non-specific effects of the drug. Folate receptors (FR) are membrane-bound surface proteins, over-expressed in numerous solid tumors, folate and folate conjugates bind to FR with higher affinity. In the present investigation, we fabricated Folic acid (FA) decorated Palbociclib loaded lipid-polymer hybrid nanoparticles (FA-PLPHNPs) using quality by design (QbD) approach and evaluated its anti-cancer activity in folate receptor-positive breast cancer cell lines. 1HNMR, ATR-FTIR spectroscopic techniques confirmed the formation of DSPE-PEG-FA ligand. The optimized FA-PLPHNPs formulation exhibited 143.36 ± 5.24 nm, 0.172 ± 0.004, -16.84 ± 0.27 mV, and 93.12 ± 0.43 % of particle size, PDI, zeta potential and % entrapment efficiency, respectively. The FA-PLPHNPs exhibited an approximately 9, 11-fold reduction in IC50 values than free Palbociclib in MCF-7 and MDA-MB-231 cells at 48 h. The role of FA in targeting breast cancer was studied by means of a receptor-blocking assay, and concluded that FA-PLPHNPs were internalized into MCF-7 and MDA-MB-231 cells by folate receptor-mediated endocytosis. FA-PLPHNPs showed higher anti-cancer efficiency and caused enhanced reactive oxygen species generation, apoptosis (Acridine orange/ ethidium bromide dual staining and Annexin V/PI staining), reduced cell migration, and colony formation. Thus, the fabricated Palbociclib-loaded FA-conjugated lipid polymer hybrid nanoparticles could act as a potential nanocarrier for the treatment of breast cancer.

The colony forming efficiency assay for toxicity testing of nanomaterials—Modifications for higher-throughput

To cope with the high number of nanomaterials manufactured, it is essential to develop high-throughput methods for in vitro toxicity screening. At the same time, the issue with interference of the nanomaterial (NM) with the read-out or the reagent of the assay needs to be addressed to avoid biased results. Thus, validated label-free methods are urgently needed for hazard identification of NMs to avoid unintended adverse effects on human health. The colony forming efficiency (CFE) assay is a label- and interference-free method for quantification of cytotoxicity by cell survival and colony forming efficiency by CFE formation. The CFE has shown to be compatible with toxicity testing of NMs. Here we present an optimized protocol for a higher-throughput set up.