Hyaluronate dots for highly efficient photodynamic therapy

Easy Synthesis and Characterization of Novel Carbon Dots Using the One-Pot Green Method for Cancer Therapy

In this study, hyaluronic acid (HA) and carboxymethyl chitosan (CMCS) were used for the synthesis of novel targeted nanocarrier carbon dots (CDC-H) with photo-luminescence using a one-step hydrothermal method. Doxorubicin (DOX), a common chemotherapeutic agent, was loaded with the CDC-H through electrostatic interactions to form DOX-CDC-H complexes as a targeted antitumor drug delivery system. The synthesized CDC-H show a particle size of approximately 6 nm and a high fluorescence quantum yield of 11.64%. The physical and chemical character properties of CDC-H and DOX-CDC-H complexes were investigated using various techniques. The results show that CDC-H have stable luminescent properties and exhibit excellent water solubility. The in vitro release study showed that DOX-CDC-H exhibited pH-dependent release for 24 h. Confocal laser scanning microscopy was applied to investigate the potential of CDC-H for cell imaging and the cellular uptake of DOX-CDC-H in different cells (NIH-3T3 and 4T1 cells), and the results confirmed the target cell imaging and cellular uptake of DOX-CDC-H by specifically binding the CD44 receptors on the surface of tumor cells. The r MTT results suggest that the DOX-CDC-H complex may induce apoptosis in 4T1 cells, reducing the cytotoxicity of free DOX-induced apoptosis. In vivo antitumor experiments of DOX-CDC-H exhibited enhanced tumor cancer therapy. CDC-H have potential applications in bioimaging and antitumor drug delivery.

pH-Sensitive Twin Liposomes Containing Quercetin and Laccase for Tumor Therapy

In this study, functional twin liposomes (TLs) were designed by linking avidin-anchored single liposomes and biotin-anchored single liposomes via avidin-biotin interactions. Here, we first punched a hole on the liposome surface using the liposome magnetoporation method to prepare functional single liposomes, which were used for safely encapsulating quercetin (QER, as a model prodrug) or laccase (LAC, as a bioactive enzyme) inside the liposomes without the use of organic solvents; the pores were then plugged by pH-sensitive glycol chitosan grafted with 3-diethylaminopropylamine (GDEAP) and avidin (or biotin). As a result, single liposomes with QER and biotin-GDEAP were efficiently coupled with other liposomes with LAC and avidin-GDEAP. We demonstrated that the TLs could accelerate QER and LAC release at acidic pH (6.8), improving the LAC-mediated oxidization of QER and significantly elevating tumor cell death, suggesting that this strategy can be used as an efficient method for the programmed action of prodrugs.

Hypoxia-Responsive Azobenzene-Linked Hyaluronate Dot Particles for Photodynamic Tumor Therapy

In this study, we developed ultra-small hyaluronate dot particles that selectively release phototoxic drugs into a hypoxic tumor microenvironment. Here, the water-soluble hyaluronate dot (dHA) was covalently conjugated with 4,4′-azodianiline (Azo, as a hypoxia-sensitive linker) and Ce6 (as a photodynamic antitumor agent), producing dHA particles with cleavable Azo bond and Ce6 (dHA-Azo-Ce6). Importantly, the inactive Ce6 (self-quenched state) in the dHA-Azo-Ce6 particles was switched to the active Ce6 (dequenched state) via the Azo linker (–N=N–) cleavage in a hypoxic environment. In vitro studies using hypoxia-induced HeLa cells (treated with CoCl₂) revealed that the dHA-Azo-Ce6 particle enhanced photodynamic antitumor inhibition, suggesting its potential as an antitumor drug candidate in response to tumor hypoxia.

pH/ROS dual-responsive supramolecular polypeptide prodrug nanomedicine based on host-guest recognition for cancer therapy

Supramolecular nanomedicine assembly combined with polypeptide prodrug could become a powerful strategy to minimize drug leakage in blood circulation and trigger sufficient drug release at tumor tissue. Here, we developed a charge-reversal amphiphilic pillar[5]arene-modified polypeptide (P5-PLL-DMA), and reactive oxygen species (ROS)-sensitive polypeptide prodrug (P-PLL-DOX) including a ROS-cleavable thioketal (TK) linker between doxorubicin (DOX) and poly(_L-lysine) (PLL), which could assemble via pillar[5]arene host-guest recognition, and further encapsulate chlorin e6 (Ce6) to obtain a supramolecular polypeptide prodrug (SPP-DOX/Ce6). The chemical conjugation to load drugs of DOX and the negatively charge of SPP-DOX/Ce6 could prevent premature drug leakage, and reduce undesirable interaction with serum proteins to enhance stability under physiological conditions (pH 7.4). Simultaneously, the carried charge of SPP-DOX/Ce6 reversed from negative to positive could effectively enhance the cellular internalization for efficient DOX delivery under acidic tumor microenvironment (pH 6.5). Upon 660 nm near-infrared light (NIR) irradiation, the ROS generated by encapsulated Ce6 rapidly cleaved the TK linker to release activated DOX, inducing the tumor-specific drug delivery. This intelligent supramolecular polypeptide prodrug based on pillar[5]arene host-guest recognition represents new avenues to develop stimulus responsive prodrug for enhanced cancer therapy with minimized the side effect. STATEMENT OF SIGNIFICANCE: In this work, a pH/ROS dual-sensitive supramolecular polypeptide prodrug (SPP-DOX/Ce6) was developed to minimize drug leakage in blood circulation and trigger sufficient drug release at tumor tissue. The chemical conjugation to load drugs of DOX via a ROS-cleavable thioketal (TK) linker and the distinctive charge-reversal capacity of SPP-DOX/Ce6 significantly enhances the stability under physiological conditions (pH 7.4), while facilitates cellular uptake at tumor site (pH 6.8). Upon 660 nm near-infrared light (NIR) irradiation, the ROS generated by encapsulated Ce6 induces the rapid cleavage of TK linker to release activated DOX, achieving a tumor-specific drug delivery. This intelligent supramolecular polypeptide prodrug SPP-DOX/Ce6 provides an effective strategy to construct stimulus responsive prodrug for enhanced cancer therapy.

A composite System Combining Self-Targeted Carbon Dots and Thermosensitive Hydrogels for Challenging Ocular Drug Delivery

We developed a composite system combining self-targeted carbon dots and thermosensitive in situ hydrogels for ocular drug delivery of diclofenac sodium (DS). DS-CD_C-HP nanoparticles were prepared by loading DS on the surface of CD_C-HP via electrostatic interactions. An orthogonal experimental design was selected to screen the optimal thermosensitive hydrogel matrices and then DS-CD_C-HP nanoparticles were embedded to form the composite system. The physicochemical properties and release behavior of this system were characterized, and in vivo fluorescence imaging was carried out. Corneal penetrability and in vitro cellular studies (cytotoxicity, cell imaging and cell uptake) were performed to test the feasibility and potential of this ocular delivery system. Finally, the optimal gel matrix consisting of Poloxamer 407: Poloxamer 188: HPMC E50 was 21:1:1 (w/v %), and the gelation temperature before adding artificial tear fluid was 26.67°C and 34.29°C, respectively. This system has the characteristics of biphasic drug release. In addition, the corneal penetrability and in vivo fluorescence study indicated that corneal transmittance was enhanced and drug retention time was extended. Cellular studies revealed that the DS-CD_C-HP-Gel has good cytocompatibility and CD44 targeting. In summary, this composite system combines carbon dots with hydrogels, offering new potential for ocular drug delivery.

Endosomal pH-Responsive Fe-Based Hyaluronate Nanoparticles for Doxorubicin Delivery

In this study, we report pH-responsive metal-based biopolymer nanoparticles (NPs) for tumor-specific chemotherapy. Here, aminated hyaluronic acid (aHA) coupled with 2,3-dimethylmaleic anhydride (DMA, as a pH-responsive moiety) (aHA-DMA) was electrostatically complexed with ferrous chloride tetrahydrate (FeCl₂/4H₂O, as a chelating metal) and doxorubicin (DOX, as an antitumor drug model), producing DOX-loaded Fe-based hyaluronate nanoparticles (DOX@aHA-DMA/Fe NPs). Importantly, the DOX@aHA-DMA/Fe NPs improved tumor cellular uptake due to HA-mediated endocytosis for tumor cells overexpressing CD44 receptors. As a result, the average fluorescent DOX intensity observed in MDA-MB-231 cells (with CD44 receptors) was ~7.9 × 10² (DOX@HA/Fe NPs, without DMA), ~8.1 × 10² (DOX@aHA-DMA_0.36/Fe NPs), and ~9.3 × 10² (DOX@aHA-DMA_0.60/Fe NPs). Furthermore, the DOX@aHA-DMA/Fe NPs were destabilized due to ionic repulsion between Fe²⁺ and DMA-detached aHA (i.e., positively charged free aHA) in the acidic environment of tumor cells. This event accelerated the release of DOX from the destabilized NPs. Our results suggest that these NPs can be promising tumor-targeting drug carriers responding to acidic endosomal pH.

Comparison Direct Synthesis of Hyaluronic Acid-Based Carbon Nanodots as Dual Active Targeting and Imaging of HeLa Cancer Cells

The present study explores the potential of carbon nanodots (CDs) synthesized from hyaluronic acid using microwave-assisted and furnace-assisted methods as bioimaging agents for cancer cells. The investigation on the effect of microwave-assisted and furnace-assisted times (2 min and 2 h) on determining CD character is dominantly discussed. Various CDs, such as HA-P1 and HA-P2 were, respectively, synthesized through the furnace-assisted method at 270 °C for 2 min and 2 h, whereas HA-M1 and HA-M2 were synthesized with the microwave-assisted method for 2 min and 2 h, respectively. Overall, various CDs were produced with an average diameter, with the maximum absorption of HA-P1, HA-P2, HA-M1, and HA-M2 at 234, 238, 221, and 217 nm, respectively. The photoluminescence spectra of these CDs showed particular emissions at 320 nm and excitation wavelengths from 340 to 400 nm. Several characterizations such as X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, and Raman spectroscopy reveal the CD properties such as amorphous structures, existence of D bands and G bands, and hydrophilic property supported with hydroxyl and carboxyl groups. The quantum yields of HA-M1, HA-M2, HA-P1, and HA-P2 were 12, 7, 9, and 23%, respectively. The cytotoxicity and in vitro activity were verified by a cell counting kit-8 assay and confocal laser scanning microscopy, which show a low toxicity with the percentage of living cells above 80%.

Synthesis and biological evaluation of fluorescent hyaluronic acid modified amorphous calcium phosphate drug carriers for tumor-targeting

Cancer is becoming a major threat to national public health security. The integration of disease diagnosis and monitoring with treatment has become a hot spot for researchers. The amorphous calcium phosphate (ACP) nanoparticles prepared by the group in the previous stage could not precisely treat the lesion without tumor targeting and imaging characteristics. In this paper, water-soluble hyaluronic acid fluorescent carbon nanoparticles (HA-FCNs) were prepared and co-interacting with ACP nanoparticles to form hyaluronic acid fluorescent carbon/amorphous calcium phosphate (HA-FCNs/ACP) nanoparticles. The basic characteristics were characterized and the biological characteristics before and after drug loading were evaluated. HA-FCNs/ACP nanoparticles have good hemocompatibility, pH responsiveness, and enzymatic release. HA-FCNs and HA-FCNs/ACP nanoparticles are dispersed in the cytoplasm through the overexpressed CD44 receptors, which are actively targeted into A549 cells. Besides, the migration of A549 cells would be inhibited after cells were treated with drug-loaded nanomaterials. Therefore, the as-prepared nanoparticles can be used to monitor and treat focal sites through tumor-targeting bioimaging, pH-responsive, and enzymatic drug release properties, thus enabling integrated diagnosis and treatment.

Redox-responsive hyaluronic acid-based nanoparticles for targeted photodynamic therapy/chemotherapy against breast cancer

Specific cellular uptake and sufficient drug release in tumor tissues are important for effective cancer therapy. Hyaluronic acid (HA), a skeleton material, could specifically bind to cluster determinant 44 (CD44) receptors highly expressed on the surface of tumor cells to realize active targeting. Cystamine (cys) is sensitive highly reductive environment inside tumor cells and was used as a connecting arm to connect docosahexaenoic acid (DHA) and chlorin e6 (Ce6) to the HA skeleton to obtain redox-sensitive polymer HA-cys-DHA/Ce6 (CHD). Nanoparticles were fabricated and loaded with chemotherapeutic drug docetaxel (DTX) by physical encapsulation. The prepared nanoparticles had significantly increased uptake by MCF-7 cells that overexpressed CD44 receptors, and DTX was effectively released at high reducing condition. Compared with mono-photodynamic therapy (PDT) or mono-chemotherapy, the prepared nanoparticles exhibited superior anti-tumor effect by inhibiting microtubule depolymerization, blocking cell cycle and generating reactive oxygen species (ROS). In vivo anti-tumor experiments proved that DTX/CHD nanoparticles had the best antitumor response versus DTX and CHD nanoparticles under near-infrared (NIR) irradiation. These studies revealed that redox-responsive DTX-loaded CHD nanoparticles held great potential for the treatment of breast cancer.

Transferrin-Conjugated pH-Responsive γ-Cyclodextrin Nanoparticles for Antitumoral Topotecan Delivery

In this study, we developed γ-cyclodextrin-based multifunctional nanoparticles (NPs) for tumor-targeted therapy. The NPs were self-assembled using a γ-cyclodextrin (γCD) coupled with phenylacetic acid (PA), 2,3-dimethylmaleic anhydride (DMA), poly(ethylene glycol) (PEG), and transferrin (Tf), termed γCDP-(DMA/PEG-Tf) NPs. These γCDP-(DMA/PEG-Tf) NPs are effective in entrapping topotecan (TPT, as a model antitumor drug) resulting from the ionic interaction between pH-responsive DMA and TPT or the host–guest interaction between γCDP and TPT. More importantly, the γCDP-(DMA/PEG-Tf) NPs can induce ionic repulsion at an endosomal pH (~6.0) resulting from the chemical detachment of DMA from γCDP, which is followed by extensive TPT release. We demonstrated that γCDP-(DMA/PEG-Tf) NPs led to a significant increase in cellular uptake and MDA-MB-231 tumor cell death. In vivo animal studies using an MDA-MB-231 tumor xenografted mice model supported the finding that γCDP-(DMA/PEG-Tf) NPs are effective carriers of TPT to Tf receptor-positive MDA-MB-231 tumor cells, promoting drug uptake into the tumors through the Tf ligand-mediated endocytic pathway and increasing their toxicity due to DMA-mediated cytosolic TPT delivery.

Alendronate/cRGD-Decorated Ultrafine Hyaluronate Dot Targeting Bone Metastasis

In this study, we report the hyaluronate dot (dHA) with multiligand targeting ability and a photosensitizing antitumor model drug for treating metastatic bone tumors. Here, the dHA was chemically conjugated with alendronate (ALN, as a specific ligand to bone), cyclic arginine-glycine-aspartic acid (cRGD, as a specific ligand to tumor integrin αvβ3), and photosensitizing chlorin e6 (Ce6, for photodynamic tumor therapy), denoted as (ALN/cRGD)@dHA-Ce6. These dots thus prepared (≈10 nm in diameter) enabled extensive cellular interactions such as hyaluronate (HA)-mediated CD44 receptor binding, ALN-mediated bone targeting, and cRGD-mediated tumor integrin αvβ3 binding, thus improving their tumor targeting efficiency, especially for metastasized MDA-MB-231 tumors. As a result, these dots improved the tumor targeting efficiency and tumor cell permeability in a metastatic in vivo tumor model. Indeed, we demonstrated that (ALN/cRGD)@dHA-Ce6 considerably increased photodynamic tumor ablation, the extent of which is superior to that of the tumor ablation of dot systems with single or double ligands. These results indicate that dHA with multiligand can provide an effective treatment strategy for metastatic bone tumors.

Cyclic RGD-Conjugated Hyaluronate Dot Bearing Cleavable Doxorubicin for Multivalent Tumor Targeting

In this study, we developed an extremely small-sized water-soluble hyaluronate dot (dHA) conjugated with cyclic RGD (cRGD) and cleavable doxorubicin (DOX, as a model antitumor drug), named cRGD@dHA-c-DOX. This dot with HA moieties (as specific ligands to tumor CD44 receptors) and cRGD moieties (as specific ligands to tumor integrin α_vβ₃) was designed to enable multivalent tumor targeting. In particular, the imine bonds, linking the DOX and dHA, can exhibit cleavage performance at endosomal pH, resulting in pH-triggered DOX release from cRGD@dHA-c-DOX. We demonstrated that cRGD@dHA-c-DOX resulted in highly improved cellular uptake and cell death in MDA-MB-231 tumor cells (CD44+, integrin α_vβ₃+) compared to those in Huh7 tumor cells (CD44-, integrin α_vβ₃-). In vivo studies using MDA-MB-231 tumor-bearing mice revealed that cRGD@dHA-c-DOX enhanced the tumor inhibition efficacy. These results suggest that cRGD@dHA-c-DOX can be utilized as a promising multivalent tumor-targeting drug carrier for highly efficient tumor treatment.

Facile fabrication of hyaluronated starch nanogels for efficient docetaxel delivery

In this study, we designed and synthesized polysaccharidic nanogels comprising starch cross-linked with hyaluronic acid. These hyaluronated starch nanogels were prepared by cross-linking primary hydroxyl groups in polysaccharides (starch and hyaluronic acid) and epoxide groups in 1,4-butanediol diglycidyl ether (used as a cross-linking agent). The nanogels take advantage of hyaluronic acid as a specific ligand for CD44 receptors overexpressed on tumors and the hyaluronic acid/starch core as a compartment for the encapsulation of docetaxel (as model antitumor drug). Here, hyaluronic acid can be enzymatically degraded by tumor cell–specific enzyme (e.g. hyaluronidase-1), which could significantly accelerate docetaxel release from the nanogels. Our experimental results demonstrate that the nanogels promote the release of docetaxel content in the presence of hyaluronidase-1 enzyme. As a result, the nanogels selectively inhibited MCF-7 (with CD44 receptor and hyaluronidase-1 enzyme) tumor cell growth in vitro, suggesting their therapeutic potential for efficient tumor ablation.

Dendritic Cell-Targeted pH-Responsive Extracellular Vesicles for Anticancer Vaccination

Immunotherapy can potentially treat cancers on a patient-dependent manner. Most of the efforts expended on anticancer vaccination parallel the efforts expended on prototypical immunization in infectious diseases. In this study, we designed and synthesized pH-responsive extracellular vesicles (EVs) coupled with hyaluronic acid (HA), 3-(diethylamino)propylamine (DEAP), monophosphoryl lipid A (MPLA), and mucin 1 peptide (MUC1), referred to as HDEA@EVAT. HDEA@EVAT potentiated the differentiation and maturation of monocytes into dendritic cells (DCs) and the priming of CD8⁺ T-cells for cancer therapy. MPLA and HA enabled HDEA@EVAT to interact with the toll-like receptor 4 and the CD44 receptor on DCs, followed by endosomal escape, owing to the protonation of pH-sensitive DEAP on the EV in conjunction with MUC1 release. The MUC1 was then processed and presented to DCs to activate CD8⁺ T-cells for additional anticancer-related immune reactions. Our findings support the anticancer vaccine activity by which HDEA@EVAT expedites the interaction between DCs and CD8⁺ T-cells by inducing DC-targeted maturation and by presenting the cancer-associated peptide MUC1.