Optical barcoding of PLGA for multispectral analysis of nanoparticle fate in vivo

Abstract

Understanding of the mechanisms by which systemically administered nanoparticles achieve delivery across biological barriers remains incomplete, due in part to the challenge of tracking nanoparticle fate in the body. Here, we develop a new approach for "barcoding" nanoparticles composed of poly(lactic-co-glycolic acid) (PLGA) with bright, spectrally defined quantum dots (QDs) to enable direct, fluorescent detection of nanoparticle fate with subcellular resolution. We show that QD labeling does not affect major biophysical properties of nanoparticles or their interaction with cells and tissues. Live cell imaging enabled simultaneous visualization of the interaction of control and targeted nanoparticles with bEnd.3 cells in a flow chamber, providing direct evidence that surface modification of nanoparticles with the cell-penetrating peptide TAT increases their biophysical association with cell surfaces over very short time periods under convective current. We next developed this technique for quantitative biodistribution analysis in vivo. These studies demonstrate that nanoparticle surface modification with the cell penetrating peptide TAT facilitates brain-specific delivery that is restricted to brain vasculature. Although nanoparticle entry into the healthy brain parenchyma is minimal, with no evidence for movement of nanoparticles across the blood-brain barrier (BBB), we observed that nanoparticles are able to enter to the central nervous system (CNS) through regions of altered BBB permeability - for example, into circumventricular organs in the brain or leaky vasculature of late-stage intracranial tumors. In sum, these data demonstrate a new, multispectral approach for barcoding PLGA, which enables simultaneous, quantitative analysis of the fate of multiple nanoparticle formulations in vivo.

Intravenously Administered, Retinoid Activating Nanoparticles Increase Lifespan and Reduce Neurodegeneration in the SOD1G93A Mouse Model of ALS

“…Particle systems serve to enhance total bioavailability of poorly soluble molecules, and enrichment of nanoparticles along the endothelial cells enables passive diffusion of hydrophobic drugs into the parenchyma (Cook et al, 2015;Medina et al, 2017). We and others have shown that nanoparticles can transfer small hydrophobic payloads through contact with cell membranes (Xu et al, 2009;Medina et al, 2017). Presumably this is the mechanism at work here.…”

“…Our lab previously demonstrated that delivery of drugs from polymeric nanoparticles can improve the efficacy of therapeutic candidates while reducing toxicity for the treatment of intracranial tumors via enhancements in bioavailability (Zhou et al, 2013;Cook et al, 2015;Householder et al, 2015Householder et al, , 2018. We have previously studied the fate of intravenously administered nanoparticles and encapsulated payloads in the central nervous system, demonstrating that delivery of hydrophobic payloads to the brain and spinal cord can be achieved even if the nanoparticles have not been designed for BBB passage (Cook et al, 2015;Medina et al, 2017). Particle systems serve to enhance total bioavailability of poorly soluble molecules, and enrichment of nanoparticles along the endothelial cells enables passive diffusion of hydrophobic drugs into the parenchyma (Cook et al, 2015;Medina et al, 2017).…”

“…We have previously studied the fate of intravenously administered nanoparticles and encapsulated payloads in the central nervous system, demonstrating that delivery of hydrophobic payloads to the brain and spinal cord can be achieved even if the nanoparticles have not been designed for BBB passage (Cook et al, 2015;Medina et al, 2017). Particle systems serve to enhance total bioavailability of poorly soluble molecules, and enrichment of nanoparticles along the endothelial cells enables passive diffusion of hydrophobic drugs into the parenchyma (Cook et al, 2015;Medina et al, 2017). We and others have shown that nanoparticles can transfer small hydrophobic payloads through contact with cell membranes (Xu et al, 2009;Medina et al, 2017).…”

Testing thousands of nanoparticles in vivo using DNA barcodes

“…In one example, scientists isotopically-barcoded silver nanoparticles with different functional peptides to evaluate potential targeting ligands [43]. Another group has used quantum dots to barcode polymeric nanoparticles; in vivo screens were performed to understand how nanoparticle surface modifications altered delivery through the blood brain barrier [44]. …”

MRI/Photoluminescence Dual-Modal Imaging Magnetic PLGA Nanocapsules for Theranostics

“…PLGA nanoparticles can be used in diagnostic and therapeutic imaging by the addition of the imaging moieties during the particle synthesis. To date, large efforts have been devoted to conjugating PLGA with semiconducting quantum dots and organic dyes to create photoluminescent PLGA nanocarriers [9][10][11]. However, conventional approaches for physically blending imaging probes within the nanoparticles can lead to incomplete conclusions or misinterpretations on the nanoparticles' biodistribution and fate [12,13].…”