The extension of in vivo optical imaging for disease screening and image-guided surgical interventions requires brightly-emitting, tissue-specific materials that optically transmit through living tissue and can be imaged with portable systems that display data in real-time. Recent work suggests that a new window across the short wavelength infrared region can improve in vivo imaging sensitivity over near infrared light. Here we report on the first evidence of multispectral, real-time short wavelength infrared imaging offering anatomical resolution using brightly-emitting rare-earth nanomaterials and demonstrate their applicability toward disease-targeted imaging. Inorganic-protein nanocomposites of rare-earth nanomaterials with human serum albumin facilitated systemic biodistribution of the rare-earth nanomaterials resulting in the increased accumulation and retention in tumor tissue that was visualized by the localized enhancement of infrared signal intensity. Our findings lay the groundwork for a new generation of versatile, biomedical nanomaterials that can advance disease monitoring based on a pioneering infrared imaging technique.

Realizing the promise of precision medicine in cancer therapy depends on identifying and tracking of cancerous growths in order to maximize treatment options and improve patient outcomes. However, this goal of early detection remains unfulfilled by current clinical imaging techniques that fail to detect diseased lesions, due to their small size and sub-organ localization. With proper probes, optical imaging techniques can overcome this limitation by identifying the molecular phenotype of tumors at both macroscopic and microscopic scales. In this study, we propose the first use of nanophotonic short wave infrared technology to molecularly phenotype small sub-surface lesions for more sensitive detection and improved patient outcomes. To this end, we designed human serum albumin encapsulated rare-earth (RE) nanoparticles (ReANCs)[1, 2] with ligands for targeted lesion imaging. AMD3100, an antagonist to CXCR4 (a chemokine receptor involved in cell motility and a classic marker of cancer metastasis) was adsorbed onto ReANCs to form functionalized ReANCs (fReANCs). Functionalized nanoparticles were able to discriminate and preferentially accumulate in receptor positive lesions when injected intraperitoneally in a subcutaneous tumor model. Additionally, fReANCs, administered intravenously, were able to target sub-tissue tumor micro-lesions, at a maximum depth of 10.5 mm, in a lung metastatic model of breast cancer. Internal lesions identified with fReANCs were 2.25 times smaller than those detected with unfunctionalized ReANCs (p < .01) with the smallest tumor being 18.9 mm3. Thus, we present an integrated nanoprobe detection platform that allows target-specific identification of sub-tissue cancerous lesions.

The identification and molecular profiling of early metastases remains a major challenge in cancer diagnostics and therapy. Most in vivo imaging methods fail to detect small cancerous lesions, a problem that is compounded by the distinct physical and biological barriers associated with different metastatic niches. Here, we show that intravenously injected rare-earth-doped albumin-encapsulated nanoparticles emitting short-wave infrared light (SWIR) can detect targeted metastatic lesions in vivo, allowing for the longitudinal tracking of multi-organ metastases. In a murine model of basal human breast cancer, the nanoprobes enabled whole-body SWIR detection of adrenal gland microlesions and bone lesions that were undetectable via contrast-enhanced magnetic resonance imaging (CE-MRI) as early as, respectively, three weeks and five weeks post-inoculation. Whole-body SWIR imaging of nanoprobes functionalized to differentially target distinct metastatic sites and administered to a biomimetic murine model of human breast cancer resolved multi-organ metastases that showed varied molecular profiles at the lungs, adrenal glands and bones. Real-time surveillance of lesions in multiple organs should facilitate pre-therapy and post-therapy monitoring in preclinical settings.

Current cancer therapies are challenged by weakly soluble drugs and by drug combinations that exhibit non-uniform biodistribution and poor bioavailability. In this study we have presented a new platform of advanced healthcare materials based on albumin nanoparticles (ANPs) engineered as tumor penetrating, delivery vehicles of combinatorially applied factors to solid tumors. These materials were designed to overcome three sequential key barriers: tissue level transport across solid tumor matrix; uptake kinetics into individual cancer cells; therapeutic resistance to single chemotherapeutic drugs. The ANPs were designed to penetrate deeper into solid tumor matrices using collagenase decoration and evaluated using a three-dimensional multicellular melanoma tumor spheroid model. Collagenase modified ANPs exhibited 1–2 orders of magnitude greater tumor penetration than unmodified ANPs into the spheroid mass after 96 hours, and showed preferential uptake into individual cancer cells for smaller sized ANPs (<100 nm). For enhanced efficacy, collagenase coated ANPs were modified with two therapeutic agents, curcumin and riluzole, with complementary mechanisms of action for combined cell cycle arrest and apoptosis in melanoma. The collagenase coated, drug loaded nanoparticles induced significantly more cell death within 3-D tumor models than the unmodified, dual drug loaded ANP particles and the kinetics of cytotoxicity was further influenced by the ANP size. Thus, multifunctional nanoparticles can be imbued with complementary size and protease activity features that allow them to penetrate solid tumors and deliver combinatorial therapeutic payload with enhanced cancer cytotoxicity but minimal collateral damage of healthy primary cells.

MRI and NIR-active, multi-modal Composite NanoCarriers (CNCs) are prepared using a simple, one-step process, Flash NanoPrecipitation (FNP). The FNP process allows for the independent control of the hydrodynamic diameter, co-core excipient and NIR dye loading, and iron oxide-based nanocrystal (IONC) content of the CNCs. In the controlled precipitation process, 10 nm IONCs are encapsulated into poly(ethylene glycol) stabilized CNCs to make biocompatible T2 contrast agents. By adjusting the formulation, CNC size is tuned between 80 and 360 nm. Holding the CNC size constant at an intensity weighted average diameter of 99 ± 3 nm (PDI width 28 nm), the particle relaxivity varies linearly with encapsulated IONC content ranging from 66 to 533 mM-1s-1 for CNCs formulated with 4 to 16 wt% IONC. To demonstrate the use of CNCs as in vivo MRI contrast agents, CNCs are surface functionalized with liver targeting hydroxyl groups. The CNCs enable the detection of 0.8 mm3 non-small cell lung cancer metastases in mice livers via MRI. Incorporating the hydrophobic, NIR dye PZn3 into CNCs enables complementary visualization with long-wavelength fluorescence at 800 nm. In vivo imaging demonstrates the ability of CNCs to act both as MRI and fluorescent imaging agents.