Hyaluronate-Thiol Passivation Enhances Gold Nanoparticle Peritumoral Distribution When Administered Intratumorally in Lung Cancer

Abstract

Biofouling is the unwanted adsorption of cells, proteins, or intracellular and extracellular biomolecules that can spontaneously occur on the surface of metal nanocomplexes. It represents a major issue in bioinorganic chemistry because it leads to the creation of a protein corona, which can destabilize a colloidal solution and result in undesired macrophage-driven clearance, consequently causing failed delivery of a targeted drug cargo. Hyaluronic acid (HA) is a bioactive, natural mucopolysaccharide with excellent antifouling properties, arising from its hydrophilic and polyanionic characteristics in physiological environments which prevent opsonization. In this study, hyaluronate-thiol (HA-SH) (MW 10 kDa) was used to surface-passivate gold nanoparticles (GNPs) synthesized using a citrate reduction method. HA functionalized GNP complexes (HA-GNPs) were characterized using absorption spectroscopy, scanning electron microscopy, zeta potential, and dynamic light scattering. GNP cellular uptake and potential dose-dependent cytotoxic effects due to treatment were evaluated in vitro in HeLa cells using inductively coupled plasma—optical emission spectrometry (ICP-OES) and trypan blue and MTT assays. Further, we quantified the in vivo biodistribution of intratumorally injected HA functionalized GNPs in Lewis Lung carcinoma (LLC) solid tumors grown on the flank of C57BL/6 mice and compared localization and retention with nascent particles. Our results reveal that HA-GNPs show overall greater peritumoral distribution (** p < 0.005, 3 days post-intratumoral injection) than citrate-GNPs with reduced biodistribution in off-target organs. This property represents an advantageous step forward in localized delivery of metal nano-complexes to the infiltrative region of a tumor, which may improve the application of nanomedicine in the diagnosis and treatment of cancer.

Zonal Intratumoral Delivery of Nanoparticles Guided by Surface Functionalization

“…The animals were intratumorally administered either citrate-, PTE-, or PEG-coated gold nanoparticles via syringe pump and then imaged again with μCT immediately postadministration (day 0) as well as on days 3, 6, and 9. Following controlled intratumoral injection, we observed via CT imaging that the citrate-GNPs consistently agglomerated as single clusters, a phenomenon also reported by our group after manual injection, 30 while the PTE-GNPs and PEG-GNPs diffused predominantly in the tumor periphery. In vivo results demonstrated remarkable differences in the intratumoral diffusion of the GNPs depending on the surface passivation.…”

“…For elemental analysis, the whole tissue was digested except for certain tumors on day 3 ( n = 4 mice/group) and day 6 ( n = 4 mice/group) that were further subsectioned. From each of these tumors, four dissections were obtained (medial periphery, medial core, lateral periphery, and lateral core), following the previously described approach . Samples were digested as previously described .…”

“…31 Samples were digested as previously described. 30 Briefly, each tissue or blood sample was kept for 1 h in 2 mL of fresh aqua regia at 60 °C until complete digestion and then diluted in 8 mL of acidic solution (10% HCl, 1% HNO 3 ). The gold content of each sample was measured and normalized to the injected dose (ID) of the GNPs and expressed as the percentage of the ID.…”

“…Gold nanoparticles were prepared as previously described. 29,30 Briefly, gold nanoparticles (∼35 nm in diameter) were synthesized by boiling 4.8 mL of 0.039 M aqueous citrate (Sigma-Aldrich) and 7 mL of 0.033 M gold(III) chloride (Sigma-Aldrich) in 600 mL of deionized water until a transition in color from yellow to black occurred, and the colloidal solution appeared dark red. After GNP synthesis, the pH of the solution was measured to be 3.6.…”

“…In addition to the administration method, the intratumoral GNP distribution profile is strongly dependent upon their physicochemical properties, especially size, surface charge, surface functionalization, and shape. − We previously demonstrated the importance of surface passivation to control GNP distribution in a murine model of lung cancer. − However, a thorough understanding of these properties for customizing nanoparticle design to achieve desired intratumor pharmacokinetics and spatiotemporal distribution profiles could be the holy grail of cancer nanomedicine, promising to advance drug delivery and optimize outcomes.…”