Beyond the imaging: Limitations of cellular uptake study in the evaluation of nanoparticles

Abstract

Poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) conjugated to a cell-penetrating peptide, TAT, was used to increase intracellular delivery of paclitaxel (PTX) to multi-drug resistant (MDR) cells. Efficient cellular uptake of the TAT-conjugated PLGA NPs was observed; however, it did not translate to increased killing of MDR cells. An investigation of drug release kinetics in phosphate-buffered saline containing Tween 80 led us to suspect that a significant fraction of the loaded PTX was released before efficient cellular uptake could occur. These results indicate that the increased cellular uptake of NPs does not always mean an enhanced drug effect and that it is critical to control both the location of NPs and the drug release from NPs together. Based on this study, we propose that two prevalent practices in NP research be reconsidered: First, the utility of a new NP system should be tested beyond the imaging level. Second, NP release kinetics should be monitored in a medium that can reflect the complexity of biological environment rather than a simple buffered saline.

Extracellular stability of nanoparticulate drug carriers

“…A similar phenomenon was observed with PLGA NS modified with a cell-penetrating peptide, TAT (Gullotti and Yeo 2012). TAT was added to enhance cellular uptake of the NS, thereby facilitating drug delivery to multidrug resistant cells.…”

“…For example, the previously mentioned PDLLA-MePEG micelles were expected to be stable, given the relatively low CMC and good colloidal stability lasting 24 h; however, they were dissociated in less than 1 h in blood (Burt et al 1999). We expected that PLGA NS would retain PTX well based on in vitro release kinetics study (Xu et al 2009) but found that the drug was released prematurely in the presence of amphiphilic components, cancelling potential advantages afforded by the carrier (Gullotti and Yeo 2012). The gaping difference between the estimated stability of NPs and their performance in biological systems is partly attributable to the lack of reliable methods to predict NP stability.…”

Strategist PLGA Nano-capsules to Deliver siRNA for Inhibition of Carcinoma and Neuroblastoma Cell Lines by Knockdown of MYC Proto-oncogene using CPPs and PNA

“…This contributed an increase in hydrodynamic size and decrease in surface charge to -5 mV after the formation of PNA layer. Although the TAT layer increased the size, the surface charge was maintained to +29 mV creating cationic TPAPLGAHNPs, which made the penetration into the cell membrane easy [35,47]. The targeting moieties converted the PLGAHNPs to cationic polymeric NPs, which made them ideal carriers for gene delivery [47].…”

“…Although the TAT layer increased the size, the surface charge was maintained to +29 mV creating cationic TPAPLGAHNPs, which made the penetration into the cell membrane easy [35,47]. The targeting moieties converted the PLGAHNPs to cationic polymeric NPs, which made them ideal carriers for gene delivery [47]. Thus after the complete functionalization of PLGAHNPS, the cellular and nuclear uptake were studied in different cell lines.…”

Mn²⁺-coordinated PDA@DOX/PLGA nanoparticles as a smart theranostic agent for synergistic chemo-photothermal tumor therapy

“…[13][14][15] Despite its popularity as a drug carrier, PLGA does not readily interact with cells and thus requires surface modification to attain this ability. 16 However, PLGA functionalization is challenged due to the lack of surface reactivity and technical complexity. 17 Recent research has demonstrated that dopamine polymerization method has been widely exploited in functionalizing various types of substrates, such as polystyrene particles, 18 V 2 O 5 nanofibers, 19 SiO 2 and Fe 3 O 4 nanoparticles.…”