Self-assembled Hyaluronic Acid Nanoparticles Research Articles

Hyaluronic Acid Nanoparticles as Nanomedicine for Treatment of Inflammatory Diseases.

Owing to their unique biological functions, hyaluronic acid (HA) and its derivatives have been explored extensively for biomedical applications such as tissue engineering, drug delivery, and molecular imaging. In particular, self-assembled HA nanoparticles (HA-NPs) have been used widely as target-specific and long-acting nanocarriers for the delivery of a wide range of therapeutic or diagnostic agents. Recently, it has been demonstrated that empty HA-NPs without bearing any therapeutic agent can be used therapeutically for the treatment of inflammatory diseases via modulating inflammatory responses. In this review, we aim to provide an overview of the significant achievements in this field and highlight the potential of HA-NPs for the treatment of inflammatory diseases.

Self-Assembled Hyaluronic Acid Nanoparticles Ameliorate Adipose Tissue Inflammation and Insulin Resistance in Diet-Induced Obese Mice

Self-assembled hyaluronic acid nanoparticles (HA-NPs), consisting of hydrophobic cores surrounded by a hydrophilic HA shell, have been extensively investigated for biomedical and pharmaceutical applications because of their biocompatibility and receptor-binding properties. Here, we report that an empty HA-NP itself not bearing any drug has therapeutic effects on adipose tissue inflammation and insulin resistance. HA-NPs inhibit not only the receptor-mediated internalization of low-molecular-weight (LMW) free HA but also LMW free HA-induced pro-inflammatory gene expression in mouse primary bone marrow-derived macrophages (BMDMs) isolated from wild type mice. Following systemic administration of Cy5.5-labeled HA-NPs, in vivo biodistribution assay and immunofluorescent staining indicate the distribution of HA-NPs and their co-localization with CD44 in adipose tissues including epididymal white adipose tissue (eWAT). However, these effects are largely reduced or rarely observed in BMDMs isolated from CD44-deficient mice. In addition, diet-induced obese (DIO) mice fed a high-fat diet (HFD) show elevated CD44 expression and HA-NP accumulation in eWAT compared to mice on standard diet. Treatment with HA-NPs in HFD-fed DIO mice suppresses macrophage infiltration into adipose tissue and adipose tissue inflammation, leading to improved insulin sensitivity and glycemic control. It is revealed that HA-NP itself can be a therapeutic agent for the treatment of type 2 diabetes. Disclosure J. Rho: None. W. Lee: None. E. Lee: None. C. Kim: None. E. Lee: None. W. Kim: None.

Self-assembled hyaluronic acid nanoparticles: Implications as a nanomedicine for treatment of type 2 diabetes

Self-assembled hyaluronic acid nanoparticles (HA-NPs) have been extensively investigated for biomedical and pharmaceutical applications owing to their biocompatibility and receptor-binding properties. Here, we report that an empty HA-NP itself not bearing any drug has therapeutic effects on adipose tissue inflammation and insulin resistance. HA-NPs inhibited not only the receptor-mediated internalization of low-molecular-weight (LMW) free HA but also LMW free HA-induced pro-inflammatory gene expression in mouse primary bone marrow-derived macrophages (BMDMs) isolated from wild-type mice, but not in CD44-null (CD44−/−) BMDMs. An in vivo biodistribution study showed the distribution of HA-NPs and their co-localization with CD44 in adipose tissues including epididymal white adipose tissues (eWATs), but these were rarely observed in the eWATs of CD44−/− mice. In addition, CD44 expression and HA-NP accumulation in the eWATs were increased in mice with diet-induced obesity (DIO) compared to lean mice. Interestingly, treatment with HA-NPs in DIO mice suppressed adipose tissue inflammation as indicated by reduced macrophage content, the production of proinflammatory cytokines and NLRP3 inflammasome activity in eWATs, leading to improved insulin sensitivity and normalized blood glucose levels. Collectively, these results suggest that an empty HA-NP itself can be a therapeutic agent for the treatment of type 2 diabetes.

Self-assembled hyaluronic acid nanoparticles for controlled release of agrochemicals and diosgenin

Commercial sodium hyaluronate (HA) and synthetic hydrazide-modified HA were functionalized with diosgenin and two agrochemicals (brassinosteroids DI31 and S7) with degree of substitution ranging from 5.6 to 13.1%. The HA-steroid conjugates were studied with FTIR, 1H NMR and differential scanning calorimetry. Dynamic light scattering revealed self-assembly of the HA-steroid conjugates into stable negatively charged nanoparticles of around 159nm–441nm in water, which after drying appeared as 140nm–370nm spherically shaped nanoparticles according to transmission electron microscopy. These nanoparticles exhibited almost constant release rates of steroids for the first 8h, demonstrating sustained steroids delivery for 72h in acidic medium. The nanoparticles formed from HA-steroid conjugates were not cytotoxic to human microvascular endothelial cells (HMVEC), while the HA- brassinosteroid nanoparticles showed in vitro agrochemical activity that was superior to the activity observed for the parent brassinosteroids DI31 and S7 at 10−5 to 10−7mgmL−1.

Dually folate/CD44 receptor-targeted self-assembled hyaluronic acid nanoparticles for dual-drug delivery and combination cancer therapy.

Nanoparticles (NPs) functionalized with targeting ligands have shown promise, but are still limited by their nonspecific uptake by certain healthy tissues and cells that express low or even comparable levels of receptors. To increase their accumulation at tumor sites while decreasing the unintended toxicity, a possible solution is the involvement of two separate tumor-specific ligands in the localization. In this study, a dual tumor-targeting drug-loaded NP system was self-assembled by the amphiphilic conjugate of methotrexate-hyaluronic acid-octadecylamine (MTX-HA-OCA) with curcumin (CUR) encapsulated within the hydrophobic core (designated as MTX-HA-OCA/CUR NPs). The advantages of this nanosystem are that the anticancer drug MTX can be utilized as a tumor-targeting ligand toward folate receptors due to its structural similarity to folic acid (FA), and HA can serve as another tumor-targeting ligand toward CD44 receptors. The MTX-HA-OCA/CUR NPs are ∼70 nm in diameter and have sustained/controlled drug release behavior. An in vitro cellular uptake and competition inhibition study exhibited that MTX-HA-OCA/CUR NPs could significantly enhance the internalization efficiency in HeLa cells via folate/CD44 receptor-mediated endocytosis as compared to HA-OCA/CUR NPs. More importantly, the in vitro cytotoxicity of MTX-HA-OCA/CUR NPs was significantly enhanced as compared to those of the HA-OCA/CUR NPs, both free drugs, and individual free drug. Furthermore, the real-time in vivo and ex vivo fluorescence imaging of HeLa tumor-bearing mice showed that MTX-HA-OCA/CUR NPs could more efficiently enhance their accumulation and improve the penetration at the tumor site as compared to HA-OCA/CUR NPs. Therefore, these dually folate/CD44 receptor-targeted self-assembled HA NPs for the co-delivery of both anticancer drugs might provide a promising strategy for dual-targeted combination cancer therapy.

Synthesis, characterization and liver targeting evaluation of self-assembled hyaluronic acid nanoparticles functionalized with glycyrrhetinic acid

Recently, polymeric materials with multiple functions have drawn great attention as the carrier for drug delivery system design. In this study, a series of multifunctional drug delivery carriers, hyaluronic acid (HA)-glycyrrhetinic acid (GA) succinate (HSG) copolymers were synthesized via hydroxyl group modification of hyaluronic acid. It was shown that the HSG nanoparticles had sub-spherical shape, and the particle size was in the range of 152.6–260.7nm depending on GA graft ratio. HSG nanoparticles presented good short term and dilution stability. MTT assay demonstrated all the copolymers presented no significant cytotoxicity. In vivo imaging analysis suggested HSG nanoparticles had superior liver targeting efficiency and the liver targeting capacity was GA graft ratio dependent. The accumulation of DiR (a lipophilic, NIR fluorescent cyanine dye)-loaded HSG-6, HSG-12, and HSG-20 nanoparticles in liver was 1.8-, 2.1-, and 2.9-fold higher than that of free DiR. The binding site of GA on HA may influence liver targeting efficiency. These results indicated that HSG copolymers based nanoparticles are potential drug carrier for improved liver targeting.

Tumor-targeting hyaluronic acid nanoparticles for photodynamic imaging and therapy

Tumor-targeted imaging and therapy have been the challenging issue in the clinical field. Herein, we report tumor-targeting hyaluronic acid nanoparticles (HANPs) as the carrier of the hydrophobic photosensitizer, chlorin e6 (Ce6) for simultaneous photodynamic imaging and therapy. First, self-assembled HANPs were synthesized by chemical conjugation of aminated 5β-cholanic acid, polyethylene glycol (PEG), and black hole quencher3 (BHQ3) to the HA polymers. Second, Ce6 was readily loaded into the HANPs by a simple dialysis method resulting in Ce6-loaded hyaluronic acid nanoparticles (Ce6-HANPs), wherein in the loading efficiency of Ce6 was higher than 80%. The resulting Ce6-HANPs showed stable nano-structure in aqueous condition and rapid uptake into tumor cells. In particular Ce6-HANPs were rapidly degraded by hyaluronidases abundant in cytosol of tumor cells, which may enable intracellular release of Ce6 at the tumor tissue. After an intravenous injection into the tumor-bearing mice, Ce6-HANPs could efficiently reach the tumor tissue via the passive targeting mechanism and specifically enter tumor cells through the receptor-mediated endocytosis based on the interactions between HA of nanoparticles and CD44, the HA receptor on the surface of tumor cells. Upon laser irradiation, Ce6 which was released from the nanoparticles could generate fluorescence and singlet oxygen inside tumor cells, resulting in effective suppression of tumor growth. Overall, it was demonstrated that Ce6-HANPs could be successfully applied to in vivo photodynamic tumor imaging and therapy simultaneously.

Preparation of hyaluronic acid nanoparticles via hydrophobic association assisted chemical cross-linking—an orthogonal modular approach

The objective of this study was to develop an efficient and stable drug delivery nanocarrier based on a dually functionalized hyaluronic acid (HA) derivative which could be used as a long circulating drug delivery vehicle. Self-assembled HA nanoparticles (HA NPs) were prepared by attaching pyrene to the HA backbone and the obtained physical NPs were stabilized by chemical cross-linking of the HA chains to form hydrophobic core–hydrophilic shell NPs. Orthogonal chemoselective reactions were applied for conversion of HA into its amphiphilic derivative and subsequent cross-linking of the formed micellar-type associates. Chemical stabilization of the physical HA associates afforded therefore very stable nanoparticles that could easily be re-suspended in aqueous media after freeze-drying. In contrast, freeze-drying of the uncross-linked physically associated particles resulted in a non-soluble material. Doxorubicin (DOX), a typical anticancer drug, was entrapped into HA NPs via ionic and/or hydrophobic interactions and used for in vitrodrug release. Higher loading efficiency and the slower release profile of DOX from HA NPs were obtained with the hydrophobically encapsulated drug. We have shown that free HA NPs were readily taken up by NIH 3T3 cells without causing any toxicity to the cells, while the DOX-loaded HA NPs resulted in increased cell death comparable to the free drug. This study clearly showed the applicability of orthogonal chemoselective modifications for the synthesis of stable HA nanogel particles as a potential cancer-targeted drug delivery system.

Self-assembled hyaluronic acid nanoparticles for active tumor targeting

Hyaluronic acid nanoparticles (HA-NPs), which are formed by the self-assembly of hydrophobically modified HA derivatives, were prepared to investigate their physicochemical characteristics and fates in tumor-bearing mice after systemic administration. The particle sizes of HA-NPs were controlled in the range of 237–424 nm by varying the degree of substitution of the hydrophobic moiety. When SCC7 cancer cells over-expressing CD44 (the receptor for HA) were treated with fluorescently labeled Cy5.5-HA-NPs, strong fluorescence signals were observed in the cytosol of these cells, suggesting efficient intracellular uptake of HA-NPs by receptor-mediated endocytosis. In contrast, no significant fluorescence signals were observed when Cy5.5-labeled HA-NPs were incubated with normal fibroblast cells (CV-1) or with excess free-HA treated SCC7 cells. Following systemic administration of Cy5.5-labeled HA-NPs with different particle sizes into a tumor-bearing mouse, their biodistribution was monitored as a function of time using a non-invasive near-infrared fluorescence imaging system. Irrespective of the particle size, significant amounts of HA-NPs circulated for two days in the bloodstream and were selectively accumulated into the tumor site. The smaller HA-NPs were able to reach the tumor site more effectively than larger HA-NPs. Interestingly, the concentration of HA-NPs in the tumor site was dramatically reduced when mice were pretreated with an excess of free-HA. These results imply that HA-NPs can accumulate into the tumor site by a combination of passive and active targeting mechanisms.

Self-assembled hyaluronic acid nanoparticles as a potential drug carrier for cancer therapy: synthesis, characterization, and in vivo biodistribution

To develop a nano-sized drug delivery system for cancer therapy, amphiphilic hyaluronic acid conjugates were synthesized by chemical conjugation of hydrophobic 5β-cholanic acid to the backbone of hyaluronic acid (HA). The HA conjugates could form nano-sized self-aggregates under physiological conditions (PBS, pH = 7.4, 37 °C) via the hydrophobic interaction among 5β-cholanic acids. The HA nanoparticles were spherical in shape and their sizes were in the range of 350–400 nm, depending on the degree of substitution of 5β-cholanic acid. From a cellular experiment using Cy5.5-labeled HA nanoparticles, it was demonstrated that they are efficiently taken up by SCC7 cancer cells which over-express CD44, the receptor for HA. When the Cy5.5-labeled HA nanoparticles were systemically administrated into the tail vein of tumor-bearing mice, most of the nanoparticles were found in tumor and liver sites. In particular, the fluorescence intensity of nanoparticles at the tumor site was 4-fold higher than that of pure HA polymer, which was confirmed by a non-invasive near-infrared fluorescence imaging system. The high tumor targeting ability of HA nanoparticles might result from both their prolonged circulation in blood and high affinity to tumor cells. These results reveal the promising potential of HA nanoparticles as a stable and effective nano-sized drug delivery system for cancer treatment.