Poly(lactic-co-glycolic acid) (PLGA) is a versatile synthetic copolymer
that is widely used in pharmaceutical applications. This is because
it is well-tolerated in the body, and copolymers of varying physicochemical
properties are readily available via ring-opening polymerization.
However, native PLGA polymers are hard to track as drug delivery carriers
when delivered to subcellular spaces, due to the absence of an easily
accessible “handle” for fluorescent labeling. Here we
show a one-step, scalable, solvent-free, synthetic route to fluorescent
blue (2-aminoanthracene), green (5-aminofluorescein), and red (rhodamine-6G)
PLGA, in which every polymer chain in the sample is fluorescently
labeled. The utility of initiator-labeled PLGA was demonstrated through
the preparation of nanoparticles, capable of therapeutic subcellular
delivery to T-helper-precursor-1 (THP-1) macrophages, a model cell
line for determining in vitro biocompatibility and
particle uptake. Super resolution confocal fluorescence microscopy
imaging showed that dye-initiated PLGA nanoparticles were internalized
to punctate regions and retained bright fluorescence over at least
24 h. In comparison, PLGA nanoparticles with 5-aminofluorescein introduced
by conventional nanoprecipitation/encapsulation showed diffuse and
much lower fluorescence intensity in the same cells and over the same
time periods. The utility of this approach for in vitro drug delivery experiments was demonstrated through the concurrent
imaging of the fluorescent drug doxorubicin (λex =
480 nm, λem = 590 nm) with carrier 5-aminofluorescein
PLGA, also in THP-1 cells, in which the intracellular locations of
the drug and the polymer could be clearly visualized. Finally, the
dye-labeled particles were evaluated in an in vivo model, via delivery to the nematode Caenorhabditis elegans, with bright fluorescence again apparent in the internal tract after
3 h. The results presented in this manuscript highlight the ease of
synthesis of highly fluorescent PLGA, which could be used to augment
tracking of future therapeutics and accelerate in vitro and in vivo characterization of delivery systems
prior to clinical translation.
Phospholipid-modified gold nanorods (phospholipid-GNRs) have demonstrated drastic cytotoxicity towards MCF-7 breast cancer cells compared to polyethylene glycol-coated GNRs (PEG-GNRs). In this study, the mechanism of cytotoxicity of phospholipid-GNRs towards MCF-7 cells was investigated using mass spectrometry-based global metabolic profiling and compared to PEGylated counterparts. The results showed that when compared to PEG-GNRs, phospholipid-GNRs induced significant and more pronounced impact on the metabolic profile of MCF-7 cells. Phospholipid-GNRs significantly decreased the levels of metabolic intermediates and end-products associated with cellular energy metabolisms resulting in dysfunction in TCA cycle, a reduction in glycolytic activity, and imbalance of the redox state. Additionally, phospholipid-GNRs disrupted several metabolism pathways essential for the normal growth and proliferation of cancer cells including impairment in purine, pyrimidine, and glutathione metabolisms accompanied by lower amino acid pools. On the other hand, the effects of PEG-GNRs were limited to alteration of glycolysis and pyrimidine metabolism. The current work shed light on the importance of metabolomics as a valuable analytical approach to explore the molecular effects of GNRs with different surface chemistry on cancer cell and highlights metabolic targets that might serve as promising treatment strategy in cancer.
Formulating protein therapeutics into nanoparticles (NPs) of poly(lactic-co-glycolic acid) (PLGA) provides key features such as protection against clearance, sustained release and less side effects by possible attachment of targeting ligands.
Coal tar (CT) is
a commonly used therapeutic agent in psoriasis
treatment. CT formulations currently in clinical use have limitations
such as toxicity and skin staining properties, leading to patient
nonadherence. The purpose of this study was to develop a nanoparticle
(NP) formulation for CT based on biocompatible poly(lactide-
co
-glycolide) (PLGA). CT was entrapped in PLGA NPs by nanoprecipitation,
and the resulting NPs were characterized using dynamic light scattering
and high-performance liquid chromatography (HPLC) to determine the
particle size and CT loading efficiency, respectively.
In
vitro
biocompatibility of the NPs was examined in human dermal
fibroblasts. Permeation, washability, and staining experiments were
carried out using skin-mimetic Strat-M membranes in Franz diffusion
cells. The optimal CT-loaded PLGA NPs achieved 92% loading efficiency
and were 133 nm in size with a polydispersity index (PDI) of 0.10
and a zeta potential of −40 mV, promoting colloidal stability
during storage. CT NPs significantly reduced the cytotoxicity of crude
CT in human dermal fibroblasts, maintaining more than 75% cell viability
at the highest concentration tested, whereas an equivalent concentration
of CT was associated with 28% viability. Permeation studies showed
that only a negligible amount of CT NPs could cross the Strat-M membrane
after 24 h, with 97% of the applied dose found accumulated within
the membrane. The superiority of CT NPs was further demonstrated by
the notably diminished staining ability and enhanced washability compared
to those of crude CT. Our findings present a promising CT nanoformulation
that can overcome its limitations in the treatment of psoriasis and
other skin disorders.
Polymeric nanoparticles (NPs) are widely used in preclinical
drug
delivery investigations, and some formulations are now in the clinic.
However, the detailed effects of many NPs at the subcellular level
have not been fully investigated. In this study, we used differentiated
THP-1 macrophage cells, as a model, to investigate the metabolic changes
associated with the use of poly (lactic-
co
-glycolic
acid) (PLGA) NPs with different surface coating or conjugation chemistries.
Liquid chromatography-mass spectrometry-based metabolic profiling
was performed on the extracts (
n
= 6) of the differentiated
THP-1 cells treated with plain, Pluronic (F-127, F-68, and P-85)-coated
and PEG–PLGA NPs and control (no treatment). Principal component
analysis and orthogonal partial least squares-discriminant analysis
(OPLS-DA) in conjunction with univariate and pathway analyses were
performed to identify significantly changed metabolites and pathways
related to exposure of the cells to NPs. OPLS-DA of each class in
the study compared to the control showed clear separation and clustering
with cross-validation values of
R
2
and
Q
2
> 0.5. A total of 105 metabolites and lipids
were found to be significantly altered in the differentiated THP-1
cell profiles due to the NP exposure, whereas more than 20 metabolic
pathways were found to be affected. These pathways included glycerophospholipid,
sphingolipid, linoleic acid, arginine and proline, and alpha-linolenic
acid metabolisms. PLGA NPs were found to perturb some amino acid metabolic
pathways and altered membrane lipids to a different degree. The metabolic
effect of the PLGA NPs on the cells were comparable to those caused
by silver oxide NPs and other inorganic nanomaterials. However, PEG–PLGA
NPs demonstrated a reduced impact on the cellular metabolism compared
to Pluronic copolymer-coated PLGA and plain PLGA NPs.
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