Real-Time and Multiplexed Photoacoustic Imaging of Internally Normalized Mixed-Targeted Nanoparticles

Abstract

Photoacoustic (PA) imaging is a developing diagnostic technique where multiple species can be simultaneously imaged with high spatial resolution in 3D if the absorbance spectrum of each species is distinct and separable. However, multiplexed PA imaging has been greatly limited by the availability of spectrally separable contrast agents that can be used in vivo. Toward this end, we present the formation and application of a series of poly ethylene glycol (PEG)-coated nanoparticles (NPs) with unique separable absorbance profiles suitable for simultaneous multiplexed imaging. As a proof-of-concept, we demonstrate this form of mixed-sample multiplexed imaging, using cRGD peptide surface-modified NPs with nonmodified NPs in a murine subcutaneous Lewis lung carcinoma tumor model. The simultaneous imaging of nonmodified NPs provides an "internal standard", to deconvolute the contributions of active-ligand and passive-NP targeting effects. Particles with 25% surface cRGD modification display 52 ± 22 fold higher liver to tumor ratio accumulation levels, while the same set of particles display only 9.8 ± 4 fold accumulation levels when internally normalized. The pharmacokinetic profiles of targeted and nontargeted NPs can be simultaneously tracked in real-time to study how biodistribtions of particles are affected by ligand modification. The internal normalization of control particles greatly enhances the precision and decreases the number of animals needed in studies of nanoparticle targeting. These new dyes are an enabling technology for PA imaging of NP fate and targeting. This is the first demonstration of real-time multiplexed PA imaging of mixed-targeted samples in vivo.

Nanoparticle targeting of Gram-positive and Gram-negative bacteria for magnetic-based separations of bacterial pathogens

“…This is especially important for optimizing cell targeting, as increasing ligand densities can improve binding in some instances, but excessively high-ligand densities can also result in decreased cell binding (Allen 2002;Cabral et al 2011;Cheng et al 2012;D'Addio et al 2013;Elias et al 2013;Kathleen et al 2007;Lee et al 2010). The FNP process enables the simultaneous encapsulation of several hydrophobic actives, including imaging modalities and hydrophobic drugs, to create theranostic NPs for novel antimicrobial treatments (Lu et al 2015(Lu et al , 2016(Lu et al , 2017Pansare et al 2012Pansare et al , 2014. We here present the development and characterization of FNPbased NPs that target Gram-negative and Gram-positive bacteria, and demonstrate proof-of-concept applications where bacteria are separated from media using commercially available and easily scalable magnetic separation setups.…”

New contrast agents for photoacoustic imaging and theranostics: Recent 5-year overview on phthalocyanine/naphthalocyanine-based nanoparticles

“…Lu et al developed multiplexed PA imaging agents of cRGD-modified nanoparticles, which can bind to α V β 3 integrin expressed in Lewis lung carcinoma tumors, and unmodified nanoparticles based on Pc/Nc macrocycles, which can internally normalize active ligand targeting effects from passive targeting such as EPR effect. 123 PA imaging of the two spectrally separable nanoparticles showed the distinct distribution of agents in the tumor site [ Fig. 5(a) ].…”

Performances of a Pristine Graphene–Microbubble Hybrid Construct as Dual Imaging Contrast Agent and Assessment of Its Biodistribution by Photoacoustic Imaging

“…Here, we show the in vivo multiplexed PA imaging of hybrid graphene PVA microbubbles, due to the well separated absorbance profiles as proved by the in vitro study. The ability to simultaneously distinguish the PA signals of endogenous and exogenous contrast agents in the same image is necessary for multiplexed imaging . Hence, the wavelength choice based on the comparison of the PA spectral features of each components, i.e., oxy, deoxy hemoglobins both present in the blood and G/PVA–PEGDA2000, as illustrated in Figure , favors the G/PVA–PEGDA2000 PA contrast at 720 nm.…”