Near Infrared Fluorescent Nanoparticles Derived from Hyaluronic Acid Improve Tumor Contrast for Image-Guided Surgery

Abstract

Tumor tissue that remains undetected at the primary surgical site can cause tumor recurrence, repeat surgery, and treatment strategy alterations that impose a significant patient and healthcare burden. Intraoperative near infrared fluorescence (NIRF) imaging is one potential method to identify remaining tumor by visualization of NIR fluorophores that are preferentially localized to the tumor. This requires development of fluorophores that consistently identify tumor tissue in different patients and tumor types. In this study we examined a panel of NIRF contrast agents consisting of polymeric nanoparticle (NP) formulations derived from hyaluronic acid (HA), with either physically entrapped indocyanine green (ICG) or covalently conjugated Cy7.5. Using orthotopic human breast cancer MDA-MB-231 xenografts in nude mice we identified two lead formulations. One, NanoICGPBA, with physicochemically entrapped ICG, showed 2.3-fold greater tumor contrast than ICG alone at 24 h (p < 0.01), and another, NanoCy7.5100-H, with covalently conjugated Cy7.5, showed 74-fold greater tumor contrast than Cy7.5 alone at 24 h (p < 0.0001). These two lead formulations were then tested in immune competent BALB/c mice bearing orthotopic 4T1 breast cancer tumors. NanoICGPBA showed 2.2-fold greater contrast than ICG alone (p < 0.0001), and NanoCy7.5100-H showed 14.8-fold greater contrast than Cy7.5 alone (p < 0.0001). Furthermore, both NanoICGPBA and NanoCy7.5100-H provided strong tumor enhancement using image-guided surgery in mice bearing 4T1 tumors. These studies demonstrate the efficacy of a panel of HA-derived NPs in delineating tumors in vivo, and identifies promising formulations that can be used for future in vivo tumor removal efficacy studies.

Hyaluronic acid formulation of near infrared fluorophores optimizes surgical imaging in a prostate tumor xenograft

“…Prior to TEM imaging, NPs (concentration 1.0 mg/mL in PBS) were placed on a formvar/silicone monoxide-coated 200 mesh copper grid and allowed to adhere for approximately 5 min, NanoVan negative stain was applied for 30 s, and the sample was blotted to remove excess solvent or material. TEM images of NanoICG and NanoCy7.5 10k-PBA NPs are also provided in our previous publications [23,32,33]. The stability of NanoICG PBA in a solution of PBS containing bovine serum albumin (BSA) has been reported [23], showing that ICG was rapidly released into albumin-containing solution across a dialysis membrane.…”

“…TEM images of NanoICG and NanoCy7.5 10k-PBA NPs are also provided in our previous publications [23,32,33]. The stability of NanoICG PBA in a solution of PBS containing bovine serum albumin (BSA) has been reported [23], showing that ICG was rapidly released into albumin-containing solution across a dialysis membrane. It was also shown that a NanoCy7.5 variant with aminopropyl-5β-cholanamide as the conjugated hydrophobic moiety, NanoCy7.5 100k-5βCA , showed limited disassembly into albumin-containing solution over a 6 h period, and then gradual disassembly over the next 72 h [23].…”

“…HA is a glycosaminoglycan found throughout the body, can have a variety of sizes composed of repeat units of β(1,4) D-glucuronic acid and β(1,3)N-acetyl-D-glucosamine, and is capable of binding to a number of receptors, including CD44, LYVE1, and Stabilin-2 (HARE) [21,22]. With its biocompatible, non-immunogenic characteristics, and potential to target overex-pressed CD44 on some tumors or accumulate passively by EPR, HA has been used in synthesis of a number of NPs for imaging and drug delivery applications [23–28]. A common method of NP formulation is to modify the hydrophilic HA backbone with hydrophobic ligands to drive self-assembly [29–31].…”

Impact of structurally modifying hyaluronic acid on CD44 interaction

“…liver and speen. 49–51 Liver cells express stabilin-2 (sub-family of CD44) and spleen cells have high expression of CD44. 52 Similar results were observed by Lin et al 53 , where HA-IR-780-based nanosystems accumulated largely in liver and spleen.…”

Light-Mediated Deep-Tissue Theranostics

“…Impressively, their migration in vivo not only can be monitored by MRI, but also by intravital TPL at the microscopic level, allowing for precise photothermal- and chemo- combination therapy. Mohs et al synthesized a panel of hyaluronic acid (HA) based nanoparticles that were either physically entrapped with indocyanine green (ICG) or covalently conjugated with Cy7.5 3. These formulations were evaluated as intraoperative optical imaging agents for accurate tumor removal.…”