Rhein-PEG-nHA conjugate as a bone targeted drug delivery vehicle for enhanced cancer chemoradiotherapy

Efficient production and purification of 32P radioisotope from sulfur by dry distillation: A practical approach with high radiochemical purity

The 32P radioisotope, with a half-life of 14.3 days and an energy level of 1.71 MeV, has diverse applications in medicine and research. Consequently, producing a carrier-free 32P radioisotope characterized by high radiochemical and radionuclide purity is imperative. Two primary methods for generating 32P radioisotopes exist: irradiating phosphorus through the nuclear reaction (n,γ) or irradiating sulfur through the nuclear reaction (n,p). Using sulfur as a target material provides several advantages. Besides the fact that the chemical element produced after irradiation (32P) differs from the irradiated element (32S), it also produces a32P radioisotope with a higher specific activity than using 31P as the target. The production of the radioisotope 32P from sulfur employs the dry distillation method, capitalizing on sulfur's easily sublimated nature. The volatility of sulfur when heated makes it easy to separate the resulting sulfur and radioisotope 32P without the need for additional reagents. This research aims to establish a practical method for producing the 32P radioisotope using the dry distillation technique. The dry distillation method utilizes a quartz ampoule containing a mixture of 32P and 35S radionuclides, a distillation tube wrapped with heating tape, and a condenser to collect the distilled sulfur. Sulfur, serving as the target material, undergoes irradiation in the reactor at the Central Irradiation Position (CIP) through the 32S(n,p)32P nuclear reaction with a fast neutron flux of 5.380 × 1013 n/cm2.sec. Separation is achieved through distillation at a temperature of 440 °C. The residual separation products are then dissolved in a 0.1 N HCl solution. The purification process involves using an AG50 WX8 cation exchange resin column, which is pre-conditioned with 0.1 N HCl. The resulting eluate contains the 32P radioisotope. The radiochemical purity of the 32P radioisotope is analyzed using thin-layer chromatography (TLC). In this analysis, a PEI Cellulose plate serves as the stationary phase, and a KH2PO4 solution acts as the mobile phase. This vacuum-free distillation method successfully separates the 32P radioisotope from sulfur, achieving a separation efficiency of 55.1 ± 9.9% (n = 7). The average activity produced after the purification process is 5.690E+10 Bq. Purifying the 32P radioisotope results in a radiochemical purity of 99.97% at Rf 0.7110, as orthophosphate, the radionuclide purity exceeds 99%.

Collagen-hydroxyapatite based scaffolds for bone trauma and regeneration: recent trends and future perspectives

Regenerative therapy, a key area of tissue engineering, holds promise for restoring damaged organs, especially in bone regeneration. Bone healing is natural to the body but becomes complex under stress and disease. Large bone deformities pose significant challenges in tissue engineering. Among various methods, scaffolds are attractive as they provide structural support and essential nutrients for cell adhesion and growth. Collagen and hydroxyapatite (HA) are widely used due to their biocompatibility and biodegradability. Collagen and nano-scale HA enhance cell adhesion and development. Thus, nano HA/collagen scaffolds offer potential solutions for bone regeneration. This review focuses on the use and production of nano-sized HA/collagen composites in bone regeneration.

Research progress of nano-delivery systems for the active ingredients from traditional Chinese medicine

INTRODUCTION

Traditional Chinese medicine (TCM) has been used for thousands of years in China, characterizing with novel pharmacological mechanisms, low toxicity, and limited side effects. However, the application of TCM active ingredients is often hindered by their physical and chemical properties, including poor solubility, low bioavailability, short half-life, toxic side effects within therapeutic doses, and instability in biological environments. Consequently, an increasing number of researchers are directing their attention towards the discovery of nano-delivery systems for TCM to overcome these clinical challenges.

OBJECTIVES

This review aims to provide the latest knowledge and results concerning the studies on the nano-delivery systems for the active ingredients from TCM.

MATERIALS AND METHODS

Recent literature relating to nano-delivery systems for the active ingredients from TCM is summarized to provide a fundamental understanding of how such systems can enhance the application of phytochemicals.

RESULTS

The nano-delivery systems of six types of TCM monomers are summarized and categorized based on the skeletal structure of the natural compounds. These categories include terpenoids, flavonoids, alkaloids, quinones, polyphenols, and polysaccharides. The paper analyzes the characteristics, types, materials used, and the efficacy achieved by TCM-nano systems. Additionally, the advantages and disadvantages of nano-drug delivery systems for TCM are summarized in this paper.

CONCLUSION

Nano-delivery systems represent a promising approach to overcoming clinical obstacles stemming from the physical and chemical properties of TCM active ingredients, thereby enhancing their clinical efficacy.

Establishment of bone-targeted nano-platform and the study of its combination with 2-deoxy-d-glucose enhanced photodynamic therapy to inhibit bone metastasis

At present, simple anti-tumor drugs are ineffective at targeting bone tissue and are not purposed to treat patients with bone metastasis. In this study, zoledronic acid (ZOL) demonstrated excellent bone-targeting properties as a bone-targeting ligand. The metal-organic framework (MOF) known as ZIF-90 was modified with ZOL to construct a bone-targeting-based drug delivery system. Chlorin e6 (Ce6) was loaded in the bone-targeted drug delivery system and combined with 2-deoxy-D-glucose (2-DG), which successfully treated bone tumors when enhanced photodynamic therapy was applied. The Ce6@ZIF-PEG-ZOL (Ce6@ZPZ) nanoparticles were observed to have uniform morphology, a particle size of approximately 210 nm, and a potential of approximately -30.4 mV. The results of the bone-targeting experiments showed that Ce6@ZPZ exhibited a superior bone-targeted effect when compared to Ce6@ZIF-90-PEG. The Ce6@ZPZ solution was subjected to 660 nm irradiation and the resulting production of reactive oxygen species increased over time, which could be further increased when Ce6@ZPZ was used in combination with 2-DG. Their combination had a stronger inhibitory capacity against tumor cells than either 2-DG or Ce6@ZPZ alone, increasing the rate of tumor cell apoptosis. The apoptosis rate caused by HGC-27 was 61.56% when 2-DG was combined with Ce6@ZPZ. In vivo results also showed that Ce6@ZPZ combined with 2-DG maximally inhibited tumor growth and prolonged mice survival compared to the other experimental groups. Therefore, the combination of PDT and glycolytic inhibitors serves as a potential option for the treatment of cancer.

Design and evaluation of 32P-labeled hydroxyapatite nanoparticles for bone tumor therapy

The clinical diagnosis and treatment of malignant bone tumors are still major clinical challenges due to their high incidence are difficulty. Targeted therapies have become a critical approach to treat bone tumors. In recent years, radiopharmaceuticals have been used widely and have shown potent and efficient results in treating bone tumors, among which ³²P and the labeled radiopharmaceuticals play an essential role. In this study, the ³²P-labeled hydroxyapatite (HA) was prepared through chemical synthesis (³²P-Hap) and physical adsorption (³²P-doped-Hap). The in vitro stability of ³²P-labeled HA was analyzed to assess the superiority of the new-found chemical synthesis. The radiolabeling yield and stability of chemical synthesis (97.6 ± 0.5%) were significantly improved compared with physical adsorption (92.7 ± 0.4%). Furthermore, the CT results corroborate that ³²P-Hap (100 μCi) +DOX group has the highest tumor suppression rate and can effectively reduce bone destruction. The results corroborate the effectiveness of the chemical synthesis and validate the application of ³²P-Hap in bone tumors. Therefore, ³²P-Hap (100 μCi) + DOX may be an effective strategy for bone metastasis treatments.

A Smart Nano-Theranostic Platform Based on Dual-microRNAs Guided Self-Feedback Tetrahedral Entropy-Driven DNA Circuit

MicroRNAs (miRNAs) can act as oncogenes or tumor suppressors, capable of up or down-regulating gene expression during tumorigenesis; they are diagnostic biomarkers or therapeutic targets for tumors. To detect low abundance of intracellular oncogenic miRNAs (onco-miRNAs) and realize synergistic gene therapy of onco-miRNAs and tumor suppressors, a smart nano-theranostic platform based on dual-miRNAs guided self-feedback tetrahedral entropy-driven DNA circuit is created. The platform as a delivery vehicle is a DNA tetrahedral framework, in which the entropy-driven DNA circuit achieves a dual-miRNAs guided self-feedback, between an in situ amplification of the onco-miRNAs and activation of suppressor miRNAs release. To test this platform, dual-miRNAs are selected, miRNA-155, an up-regulated miRNA, as cancer indicators, and miRNA-122, a down-regulated miRNA as therapy targets in hepatocellular carcinoma, respectively. Through the circuit, the platform to detect onco-miRNAs at femtomolar level as well as visualized miRNAs inside cells, fixed tissues, and mice is programmed. Furthermore, triggered by miRNA-155, preloaded miRNA-122 is amplified via the self-feedback and released into target cells; the sudden increase of miRNA-122 and simultaneous decrease of miRNA-155 synergistically served as therapeutic drugs for gene regulation with enhanced antitumor efficacy and superior biosafety. It is envisioned that this nano-theranostic platform will initiate an essential step toward tumor theranostics in personalized/precise medicine.

Nano-Hydroxyapatite Composite Scaffolds Loaded with Bioactive Factors and Drugs for Bone Tissue Engineering

Nano-hydroxyapatite (n-HAp) is similar to human bone mineral in structure and biochemistry and is, therefore, widely used as bone biomaterial and a drug carrier. Further, n-HAp composite scaffolds have a great potential role in bone regeneration. Loading bioactive factors and drugs onto n-HAp composites has emerged as a promising strategy for bone defect repair in bone tissue engineering. With local delivery of bioactive agents and drugs, biological materials may be provided with the biological activity they lack to improve bone regeneration. This review summarizes classification of n-HAp composites, application of n-HAp composite scaffolds loaded with bioactive factors and drugs in bone tissue engineering and the drug loading methods of n-HAp composite scaffolds, and the research direction of n-HAp composite scaffolds in the future is prospected.

In vitro and in vivo Evaluation of Folic Acid Modified DOX-Loaded 32P-nHA Nanoparticles in Prostate Cancer Therapy

Background

Prostate cancer (PCa) ranks second in the incidence of all malignancies in male worldwide. The presence of multi-organ metastases and tumor heterogeneity often leads to unsatisfactory outcomes of conventional radiotherapy treatments. This study aimed to develop a novel folate-targeted nanohydroxyapatite (nHA) coupling to deliver adriamycin (Doxorubicin, DOX), ³²P, and ^99mTc simultaneously for the diagnosis and treatment of prostate-specific membrane antigen (PSMA) positive prostate cancer.

Methods

The spherical nHA was prepared by the biomimetic method and characterized. Folic acid (FA) was coupled to nHA with polyethylene glycol (PEG), and the grafting ratio of PEG-nHA and FA-PEG-nHA was determined by the thermogravimetric analysis (TGA) method. In addition, ³²P, ^99mTc, and DOX were loaded on nHA by physisorption. And the labeling rate and stability of radionuclides were measured by a γ-counter. The loading and release of DOX at different pH were determined by the dialysis method. Targeting of FA-PEG-nHA loaded with ^99mTc was verified by in vivo SPECT imaging. In vitro anti-tumor effect of ³²P/DOX-FA-PEG-nHA was assessed with apoptosis assay. The safety of the nano-drugs was verified by histopathological analysis.

Results

The SEM images showed that the synthesized nHA was spherical with uniform particle size (average diameter of about 100nm). The grafting ratio is about 10% for PEG and about 20% for FA. The drug loading and the delayed release of DOX at different pH confirmed its long-term therapeutic ability. The labeling of ³²P and ^99mTc was stable and the labeling rate was great. SPECT showed that FA-PEG-nHA showed well in vivo tumor targeting and less damage to normal tissues.

Conclusion

FA-targeted nHA loaded with ³²P, ^99mTc, and DOX may be a new diagnostic and therapeutic strategy for targeting PSMA-positive prostate cancer tumors, which may achieve better therapeutic results while circumventing the severe toxic side effects of conventional chemotherapeutic agents.

Modification and Functionalization of Polymers for Targeting to Bone Cancer and Bone Regeneration

Bone is one of the most complex, inaccessible body structures, responsible for calcium storage and haematopoiesis. The second highest cause of death across the world is cancer. Amongst all the types of cancers, bone cancer treatment modalities are limited due to the structural complexity and inaccessibility of bones. The worldwide incidence of bone diseases and bone defects due to cancer, infection, trauma, age-related bone degeneration is increasing. Currently different conventional therapies are available for bone cancer such as chemotherapy, surgery and radiotherapy, but they have several disadvantages associated with them. Nanomedicine is being extensively researched as viable therapeutics to mitigate drug resistance in cancer therapy and promote bone regeneration. Several natural polymers such as chitosan, dextran, alginate, hyaluronic acid, and synthetic polymers like polyglycolic acid, poly(lactic-co-glycolic acid), polycaprolactone are investigated for their application in nanomedicine for bone cancer treatment and bone regeneration. Nanocarriers have shown promising results in preclinical experimental studies. However, they still face a major drawback of inadequate targetability. The paper summarizes the status of research and the progress made so far in modifications and functionalization of natural polymers for improving their site specificity and targeting for effective treatment of bone cancer and enhancing bone regeneration.

Focusing on the Role of Natural Products in Overcoming Cancer Drug Resistance: An Autophagy-Based Perspective

Autophagy is a critical cellular adaptive response in tumor formation. Nutritional deficiency and hypoxia exacerbate autophagic flux in established malignancies, promoting tumor cell proliferation, migration, metastasis, and resistance to therapeutic interventions. Pro-survival autophagy inhibition may be a promising treatment option for advanced cancer. Furthermore, excessive or persistent autophagy is cytotoxic, resulting in tumor cell death. Targeted autophagy activation has also shown significant promise in the fight against tumor drug resistance. Several research groups have examined the ability of natural products (NPs) such as alkaloids, terpenoids, polyphenols, and anthraquinones to serve as autophagy inhibitors or activators. The data support the capacity of NPs that promote lethal autophagy or inhibit pro-survival autophagy from being employed against tumor drug resistance. This paper discusses the potential applications of NPs that regulate autophagy in the fight against tumor drug resistance, some limitations of the current studies, and future research needs and priorities.

Hydroxyapatite Biobased Materials for Treatment and Diagnosis of Cancer

Great advances in cancer treatment have been undertaken in the last years as a consequence of the development of new antitumoral drugs able to target cancer cells with decreasing side effects and a better understanding of the behavior of neoplastic cells during invasion and metastasis. Specifically, drug delivery systems (DDS) based on the use of hydroxyapatite nanoparticles (HAp NPs) are gaining attention and merit a comprehensive review focused on their potential applications. These are derived from the intrinsic properties of HAp (e.g., biocompatibility and biodegradability), together with the easy functionalization and easy control of porosity, crystallinity and morphology of HAp NPs. The capacity to tailor the properties of DLS based on HAp NPs has well-recognized advantages for the control of both drug loading and release. Furthermore, the functionalization of NPs allows a targeted uptake in tumoral cells while their rapid elimination by the reticuloendothelial system (RES) can be avoided. Advances in HAp NPs involve not only their use as drug nanocarriers but also their employment as nanosystems for magnetic hyperthermia therapy, gene delivery systems, adjuvants for cancer immunotherapy and nanoparticles for cell imaging.

A bone-targeting drug delivery vehicle of a metal-organic framework conjugate with zoledronate combined with photothermal therapy for tumor inhibition in cancer bone metastasis

Chemotherapy is a conventional treatment method for metastatic bone cancer, but it has limitations, such as lower drug-targeting of bone tissues and serious side effects. Bone metastasis almost always occurs in advanced cancer, and most patients in this period have strong drug resistance, which further worsens the curative effect. To address the above-mentioned difficulties, a drug delivery platform is proposed in this paper that accomplishes the bone-targeting of drugs to efficiently inhibit tumors. First, the anti-cancer drugs 5-fluorouracil (5-Fu) and indocyanine green (ICG) were loaded into a zeolitic imidazolate framework (ZIF-90) to form 5-Fu/ICG@ZIF-90. Polyethylene glycol with zoledronic acid (ZOL) was encapsulated using 5-Fu/ICG@ZIF-90 to synthesize 5-Fu/ICG@ZIF-90-PEG-ZOL nanoparticles, which showed dimensional stability, good thermal stability, and bone-targeting ability. Second, the in vitro anti-cancer activity of the designed platform was investigated using cytotoxicity, apoptosis, live-dead staining, cell cycle, and cell ultrathin section analysis. The results indicated that the nanoparticles inhibited MCF-7 cell activity when chemotherapy was combined with PTT. Finally, H&E staining and TUNEL detection were performed in mouse organs and tumors. The nanoparticles combined with photothermal therapy (PTT) and triggered by near-infrared irradiation induce apoptosis of tumor cells in vivo, displaying a better efficacy of combined chemotherapy and photothermal therapy. Experiments conducted on the 5-Fu/ICG@ZIF-90-PEG-ZOL nanoparticles demonstrated their promising performance for cancer bone metastasis inhibition.

Calcium Phosphate-Based Bioceramics in the Treatment of Osteosarcoma: Drug Delivery Composites and Magnetic Hyperthermia Agents

The use of biomaterials in medicine is not recent, and in the last few decades, the research and development of biocompatible materials had emerged. Hydroxyapatite (HAp), a calcium phosphate that constitutes a large part of the inorganic composition of human bones and teeth, has been used as an interesting bioceramic material. Among its applications, HAp has been used to carry antitumor drugs, such as doxorubicin, cisplatin, and gemcitabine. Such HAp-based composites have an essential role in anticancer drug delivery systems, including the treatment of osteosarcoma. In addition, the association of this bioceramic with magnetic nanoparticles (MNPs) has also been used as an effective agent of local magnetic hyperthermia. Further, the combined approach of the aforementioned techniques (HAp scaffolds combined with anti-tumor drugs and MNPs) is also an attractive therapeutical alternative. Considering the promising role of the use of bioceramics in modern medicine, we proposed this review, presenting an updated perspective on the use of HAp in the treatment of cancer, especially osteosarcoma. Finally, after giving the current progress in this field, we highlight the urgent need for efforts to provide a better understanding of their potential applications.

Enhancement of Cancer Chemotherapeutic Efficacy via Bone-Targeted Drug Delivery Carrier in Bone Metastases

Purpose

Bone metastases are common in malignant tumors, especially for the advanced cancers. Chemotherapy is an important treatment in clinic, but the application is limited due to the severe adverse reactions. We try to design bone-targeted drug delivery systems (DDS) for the delivery of chemotherapeutic drugs in bone metastatic carcinoma.

Material and Methods

We added alendronate (Aln) to metal organic framework (MOF) to synthesize a new bone-targeted DDS named Aln-MOF. Doxorubicin (DOX) as a classic anti-cancer drug was encapsulated. The material characterization, drug release and bone affinity were detected. In vitro experiment, the cell toxicity was detected by cck-8 test and cellular uptake were detected by laser scanning confocal microscope and flow cytometry. In vivo experiment, the pharmacokinetics of DDS in the blood was analyzed by fluorescence spectrophotometer and the biodistribution was detected by a multi-mode optical in vivo imaging system. The anti-tumor effects of MOF_DOX and Aln-MOF_DOX were evaluated by monitoring the tumor volume and weight during the animal experiment. In addition, the toxicity of DDS to different organs was determined by HE staining.

Results

Aln-MOF showed good stability, no cytotoxicity and better bone affinity than MOF. Both MOF_DOX and Aln-MOF_DOX could release DOX, and the release rate at pH = 5.5 was faster than the rate at pH = 7.4. The cellular uptake of Aln-MOF and MOF showed no difference. Aln-MOF had a long retention time in blood, which is beneficial for the enrichment of Aln-MOF in tumor sites. Aln-MOF mainly concentrated at bone metastases in mice. MOF_DOX and Aln-MOF_DOX could effectively delay tumor progression, and the effect of Aln-MOFDOX was more obvious (P < 0.05).

Conclusion

Our study confirmed that Aln-MOF has good stability, bone targeting and biosafety. Aln-MOF_DOX could release DOX and effectively kill tumor cells of bone metastases. Aln-MOF_DOX has a promising prospect in the treatment of bone metastasis.

Targeting bone microenvironments for treatment and early detection of cancer bone metastatic niches

Bone tissues are the main metastatic sites of many cancers, and bone metastasis is an important cause of death. When bone metastasis occurs, dynamic interactions between tumor cells and bone tissues promote changes in the tumor-bone microenvironments that are conducive to tumor growth and progression, which also promote several related diseases, including pathological fracture, bone pain, and hypercalcemia. Accordingly, it has obvious clinical benefits for improving the cure rate and reducing the occurrence of related diseases through targeting bone microenvironments for the treatment and early detection of cancer bone metastasis niches. In this review, we briefly analyzed the relationship between bone microstructures and tumor metastasis, as well as microenvironmental changes in osteoblasts, osteoclasts, immune cells, and extracellular and bone matrixes caused when metastatic tumor cells colonize bones. We also discuss novel designs in nanodrugs for inhibiting tumor proliferation and migration through targeting to tumor bone metastases and abnormal bone-microenvironment components. In addition, related researches on the early detection of bone and multi-organ metastases by nanoprobes are also introduced. And we look forward to provide some useful proposals and enlightenments on nanotechnology-based drug delivery and probes for the treatment and early detection of bone metastasis.

Advances of Nanomedicine in Radiotherapy

Radiotherapy (RT) remains one of the current main treatment strategies for many types of cancer. However, how to improve RT efficiency while reducing its side effects is still a large challenge to be overcome. Advancements in nanomedicine have provided many effective approaches for radiosensitization. Metal nanoparticles (NPs) such as platinum-based or hafnium-based NPs are proved to be ideal radiosensitizers because of their unique physicochemical properties and high X-ray absorption efficiency. With nanoparticles, such as liposomes, bovine serum albumin, and polymers, the radiosensitizing drugs can be promoted to reach the tumor sites, thereby enhancing anti-tumor responses. Nowadays, the combination of some NPs and RT have been applied to clinical treatment for many types of cancer, including breast cancer. Here, as well as reviewing recent studies on radiotherapy combined with inorganic, organic, and biomimetic nanomaterials for oncology, we analyzed the underlying mechanisms of NPs radiosensitization, which may contribute to exploring new directions for the clinical translation of nanoparticle-based radiosensitizers.

Aptamer-mediated synthesis of multifunctional nano-hydroxyapatite for active tumour bioimaging and treatment

OBJECTIVES

The nano-hydroxyapatite (nHAp) is widely used to develop imaging probes and drug carriers due to its excellent bioactivity and biocompatibility. However, traditional methods usually need cumbersome and stringent conditions such as high temperature and post-modification to prepare the functionalized nHAp, which do not benefit the particles to enter cells due to the increased particle size. Herein, a biomimetic synthesis strategy was explored to achieve the AS1411-targeted tumour dual-model bioimaging using DNA aptamer AS1411 as a template. Then, the imaging properties and the biocompatibility of the synthesized AS-nFAp:Gd/Tb were further investigated.

MATERIALS AND METHODS

The AS-nFAp:Gd/Tb was prepared under mild conditions through a one-pot procedure with AS1411 as a template. Besides, the anticancer drug DOX was loaded to AS-nFAp:Gd/Tb so as to achieve the establishment of a multifunctional nano-probe that integrated the tumour diagnosis and treatment. The AS-nFAp:Gd/Tb was characterized by transmission electron microscopy (TEM), energy disperse X-ray Spectroscopy (EDS) mapping, X-ray photoelectron spectroscopy (XPS) spectrum, X-ray diffraction (XRD), fourier-transformed infrared (FTIR) spectroscopy, capillary electrophoresis analyses, zeta potential and particle sizes. The in vitro magnetic resonance imaging (MRI) and fluorescence imaging were performed on an MRI system and a confocal laser scanning microscope, respectively. The potential of the prepared multifunctional nHAp for a targeted tumour therapy was investigated by a CCK-8 kit. And the animal experiments were conducted on the basis of the guidelines approved by the Animal Care and Use Committee of Sichuan University, China.

RESULTS

In the presence of AS1411, the as-prepared AS-nFAp:Gd/Tb presented a needle-like morphology with good monodispersity and improved imaging performance. Furthermore, due to the specific binding between AS1411 and nucleolin up-expressed in cancer cells, the AS-nFAp:Gd/Tb possessed excellent AS1411-targeted fluorescence and MRI imaging properties. Moreover, after loading chemotherapy drug DOX, in vitro and in vivo studies showed that DOX@AS-nFAp:Gd/Tb could effectively deliver DOX to tumour tissues and exert a highly effective tumour inhibition without systemic toxicity compared with pure DOX.

CONCLUSIONS

The results indicated that the prepared multifunctional nHAp synthesized by a novel biomimetic strategy had outstanding capabilities of recognition and treatment for the tumour and had good biocompatibility; hence, it might have a potential clinical application in the future.

Zoledronic Acid-Loaded Hybrid Hyaluronic Acid/Polyethylene Glycol/Nano-Hydroxyapatite Nanoparticle: Novel Fabrication and Safety Verification

Osteosarcoma is a malignant tumor that often occurs in adolescents and children. Zoledronic acid, a new-generation bisphosphonate, has been widely used as an antitumor drug to inhibit bone metastasis. However, the rapid renal elimination results in low effective concentrations. Meanwhile, high-dose intravenous zoledronic acid administration leads to severe side effects. The present study fabricated an organic-inorganic hybrid nanoparticle as the carrier of zoledronic acid. The rod-like nanoparticle, which had 150-nm length and 40-nm cross-sectional diameter, consisted of a hyaluronic acid/polyethylene glycol (HA-PEG) polymer shell and a nano-hydroxyapatite (nHA) core, with zoledronic acid molecules loading on the surface of nHA and clearance of HA-PEG shell. The nanoparticle was characterized by microscopic analysis, in vitro release study, cytotoxicity analysis, and in vivo immune response examination. Results showed that the compact and stable structure could achieve high drug loading efficiency, sustained drug release, and great biocompatibility. In vitro and in vivo experiments revealed the low cytotoxicity and acceptable immune response under low-dose nanoparticle treatment, indicating its potential application for future osteosarcoma therapeutic strategies.