Metal organic framework-coated gold nanorod as an on-demand drug delivery platform for chemo-photothermal cancer therapy

Gold Nanorod-Embedded PDMS Micro-Pillar Array for Localized Photothermal Stimulation

Gold nanorods (GNRs) are one of the most promising biomaterial choices for the photothermal activation of neurons due to their relative biocompatibility, unique photothermal properties, and broad optical tunability through their synthetic shape control. While photothermal stimulation using randomly accumulated GNRs successfully demonstrates the potential treatment of functional neural disorders by modulating the neuronal activities using localized heating, there are limited demonstrations to translate this new concept into large-arrayed neural stimulations. In this paper, we report an arrayed PDMS micropillar platform in which GNRs are embedded as pixel-like, arrayed photothermal stimulators at the tips of the pillars. The proposed platform will be able to localize GNRs at predetermined pillar positions and create thermal stimulations using near-infrared (NIR) light. This will address the limitations of randomly distributed GNR-based approaches. Furthermore, a flexible PDMS pillar structure will create intimate interfaces on target cells. By characterizing the spatiotemporal temperature change in the platform with rhodamine B dye, we have shown that the localized temperature can be optically modulated within 4°C, which is in the range of temperature variation required for neuromodulation using NIR light. We envision that our proposed platform has the potential to be applied as a photothermal, neuronal stimulation interface with high spatiotemporal resolution.

Gold nanorods as biocompatible nano-agents for the enhanced photothermal therapy in skin disorders

Rod-shaped gold nanomaterials, known as gold nanorods (GNRs), may undergo specific surface alterations, because of their straightforward surface chemistry. This feature makes them appropriate for use as functional and biocompatible nano-formulations. By optimizing the absorption of longitudinally localized surface plasmon resonance (LSPR) in the near-infrared (NIR) region, which corresponds to the NIR bio-tissue window, GNRs with appropriate modifications may improve the results of photothermal treatment (PTT). In dermatology, potential noninvasive uses of GNRs to enhance wound healing, manage infections, combat cutaneous malignancies, and remodel skin tissues via PTT have attracted research attention in recent years. In this review, the basic properties of GNRs, such as shape, size, optical performance, photothermal efficiency, and metabolism, are discussed firstly. Then, the disadvantages of using these particles in photodynamic therapy (PDT) are proposed. Next, biological applications of GNRs-based PTT are summarized in detail. Finally, the limitations and future perspectives of this research are summarized, providing a comprehensive outlook for prospective GNRs with PTT.

Recent Advances in Engineering Carriers for siRNA Delivery

RNA interference (RNAi) technology has been a promising treatment strategy for combating intractable diseases. However, the applications of RNAi in clinical are hampered by extracellular and intracellular barriers. To overcome these barriers, various siRNA delivery systems have been developed in the past two decades. The first approved RNAi therapeutic, Patisiran (ONPATTRO) using lipids as the carrier, for the treatment of amyloidosis is one of the most important milestones. This has greatly encouraged researchers to work on creating new functional siRNA carriers. In this review, the recent advances in siRNA carriers consisting of lipids, polymers, and polymer-modified inorganic particles for cancer therapy are summarized. Representative examples are presented to show the structural design of the carriers in order to overcome the delivery hurdles associated with RNAi therapies. Finally, the existing challenges and future perspective for developing RNAi as a clinical modality will be discussed and proposed. It is believed that the addressed contributions in this review will promote the development of siRNA delivery systems for future clinical applications.

Targeted Delivery of Gemcitabine for Precision Therapy of Cholangiocarcinoma Using Hyaluronic Acid-Modified Metal-Organic Framework Nanoparticles

Chemotherapy is widely recognized as an important approach for the treatment of cholangiocarcinoma. Gemcitabine (GEM) has been considered a first-line drug for treating cholangiocarcinoma due to its ability to effectively inhibit the proliferation, migration, and invasion of liver cancer cells. However, the systemic toxicity, premature degradation, and lack of tumor-targeting properties of GEM limit its application in cholangiocarcinoma chemotherapy. Additionally, precise targeted delivery of GEM is necessary to align with the current concept of precision medicine. In this study, considering the overexpression of hyaluronic acid (HA) receptors (CD44) on cholangiocarcinoma cells, we designed GEM@ZIF-67-HA NPs by loading GEM onto ZIF-67 and modifying its surface with HA. The structure, size, morphology, and elemental composition of GEM@ZIF-67-HA were analyzed using transmission electron microscopy, Fourier transform infrared spectroscopy, ζ-potential, and isothermal adsorption. Cell toxicity experiments demonstrated that GEM@ZIF-67-HA NPs not only reduced cytotoxicity to normal cells but also effectively inhibited the viability of two types of cholangiocarcinoma tumor cells. In a subcutaneous tumor model, GEM@ZIF-67-HA significantly suppressed tumor growth. The tumor-targeting and controllable properties of GEM@ZIF-67-HA NPs hold promise for further development in the strategy of precise targeted therapy for cholangiocarcinoma.

Biomedical application of metal-organic frameworks (MOFs) in cancer therapy: Stimuli-responsive and biomimetic nanocomposites in targeted delivery, phototherapy and diagnosis

The nanotechnology is an interdisciplinary field that has become a hot topic in cancer therapy. Metal-organic frameworks (MOFs) are porous materials and hybrid composites consisted of organic linkers and metal cations. Despite the wide application of MOFs in other fields, the potential of MOFs for purpose of cancer therapy has been revealed by the recent studies. High surface area and porosity, significant drug loading and encapsulation efficiency are among the benefits of using MOFs in drug delivery. MOFs can deliver genes/drugs with selective targeting of tumor cells that can be achieved through functionalization with ligands. The photosensitizers and photo-responsive nanostructures including carbon dots and gold nanoparticles can be loaded in/on MOFs to cause phototherapy-mediated tumor ablation. The immunogenic cell death induction and increased infiltration of cytotoxic CD8+ and CD4+ T cells can be accelerated by MOF platforms in providing immunotherapy of tumor cells. The stimuli-responsive MOF platforms responsive to pH, redox, enzyme and ion can accelerate release of therapeutics in tumor site. Moreover, MOF nanocomposites can be modified ligands and green polymers to improve their selectivity and biocompatibility for cancer therapy. The application of MOFs for the detection of cancer-related biomarkers can participate in the early diagnosis of patients.

Anti-osteosarcoma trimodal synergistic therapy using NiFe-LDH and MXene nanocomposite for enhanced biocompatibility and efficacy

Osteosarcoma is usually resistant to immunotherapy and, thus primarily relies on surgical resection and high-dosage chemotherapy. Unfortunately, less invasive or toxic therapies such as photothermal therapy (PTT) and chemodynamic therapy (CDT) generally failed to show satisfactory outcomes. Adequate multimodal therapies with proper safety profiles may provide better solutions for osteosarcoma. Herein, a simple nanocomposite that synergistically combines CDT, PTT, and chemotherapy for osteosarcoma treatment was fabricated. In this composite, small 2D NiFe-LDH flakes were processed into 3D hollow nanospheres via template methods to encapsulate 5-Fluorouracil (5-FU) with high loading capacity. The nanospheres were then adsorbed onto larger 2D Ti3C2 MXene monolayers and finally shielded by bovine serum albumin (BSA) to form 5-FU@NiFe-LDH/Ti3C2/BSA nanoplatforms (5NiTiB). Both in vitro and in vivo data demonstrated that the 5-FU induced chemotherapy, NiFe-LDH driven chemodynamic effects, and MXene-based photothermal killing collectively exhibited a synergistic "all-in-one" anti-tumor effect. 5NiTiB improved tumor suppression rate from <5% by 5-FU alone to ∼80.1%. This nanotherapeutic platform achieved higher therapeutic efficacy with a lower agent dose, thereby minimizing side effects. Moreover, the composite is simple to produce, enabling the fine-tuning of dosages to suit different requirements. Thus, the platform is versatile and efficient, with potential for further development.

Gold nanorod-chitosan based nanocomposites for photothermal and chemoembolization therapy of breast cancer

Gold nanorods (AuNR) have received significant attention in tumor thermo-chemotherapy. However, insufficient thermal availability limits the in vivo highly efficient applications of AuNR in photothermal therapy. In this study, we have fabricated N-isopropylacrylamide grafted O-carboxymethyl chitosan nanoparticles (NCMC NPs) with thermo-responsive properties for co-encapsulating AuNR and doxorubicin (DOX), forming AuNR@NCMC/DOX nanocomposites (NCs). As a result of the thermo- and photothermal-responsiveness, AuNR@NCMC/DOX NCs exhibited irreversible aggregation at high temperature and under near-infrared (NIR) irradiation with an increase of size to 3 μm. When AuNR@NCMC/DOX NCs reached tumor sites following intravenous administration, they were located in the tumor vessels under NIR irradiation due to an embolization effect. This response enhanced tumor targeting, on-demand release, and the thermal performance of AuNR@NCMC/DOX NCs. We have observed higher tumor accumulation of DOX and AuNR with subsequent stronger inhibition of tumor growth than that achieved without NIR irradiation. The development of AuNR-based NCs with multiple smart responsivenesses at tumors can provide a promising paradigm for solid tumor treatment via the cooperative effects of photothermal therapy and chemoembolization.

Au/Pt@ZIF-90 Nanoenzyme Capsule-Based "Explosive" Signal Amplifier for "All-in-Tube" POCT

The sensitive, convenient, and visual detection of low-concentration disease markers in biological samples has always been a priority in disease diagnosis. However, existing research has been problematic due to complex operation and unsatisfactory sensitivity. Consequently, an "explosive" signal amplification platform based on Au/Pt@ZIF-90 was developed for sensitive visual detection of disease markers. In this study, a controllable and explosively released Au/Pt nanoparticles (NPs) "nanoenzyme capsule" was prepared by encapsulating Au/Pt NPs with excellent peroxidase activity in ZIF-90. This was achieved by adjusting the particle size of ZIF-90 and the encapsulation amount of Au/Pt NPs. Using the prepared capsules as the signal output module and aptamer as the target recognition module, an "All-in-Tube" portable point-of-care (POC) platform was constructed by integrating the Au/Pt@ZIF-90/filter paper and TMB/strips into an Eppendorf (EP) tube. By utilizing specific competitive binding of targets to aptamers, the platform enabled the sensitive and convenient measurement of small molecular disease markers. Taking adenosine as the proof of concept, the portable detection achieved excellent sensitivity. Moreover, the platform can achieve universal detection of various targets by varying the aptamer sequence. This signal amplification strategy provides a design pattern for the detection of low-concentration targets in biological samples and holds significant potential in the fields of disease diagnosis and environmental monitoring.

Recent advances and prospects of metal-organic frameworks in cancer therapies

Metal-organic frameworks (MOFs) have been broadly applied in biomedical and other fields. MOFs have high porosity, a large comparative area, and good biostability and have attracted significant attention, especially in cancer therapies. This paper presents the latest applications of MOFs in chemodynamic therapy (CDT), sonodynamic therapy (SDT), photodynamic therapy (PDT), photothermal therapy (PTT), immunotherapy (IT), and combination therapy for breast cancer. A combination therapy is the combination of two different treatment modalities, such as CDT and PDT combination therapy, and is considered more effective than separate therapies. Herein, we have also discussed the advantages and disadvantages of combination therapy in the treatment of breast cancer. This paper aims to illustrate the potential of MOFs in new cancer therapeutic approaches, discuss their potential advantages, and provide some reflections on the latest research results.

Stimuli-responsive silk fibroin for on-demand drug delivery

Stimuli-responsive "smart" hydrogel biomaterials have attracted great attention in the biomedical field, especially in designing novel on-demand drug delivery systems. As a handful natural biomaterial approved by US Food and Drug Administration, silk fibroin (SF) has unique high temperature resistance as well as tunable structural composition. These properties make it one of the most ideal candidates for on-demand drug delivery. Meanwhile, recent advances in polymer modification and nanomaterials have fostered the development of various stimuli-responsive delivery systems. Here, we first review the recent advance in designing responsive SF-based delivery systems in different stimulus sources. These systems are able to release mediators in a desired manner in response to specific stimuli in active or passive manners. We then describe applications of these specially designed responsive delivery systems in wound healing, tumor therapy, as well as immunomodulation. We also discuss the future challenges and prospects of stimuli-responsive SF-based delivery systems.

Utilization of Functionalized Metal–Organic Framework Nanoparticle as Targeted Drug Delivery System for Cancer Therapy

Cancer is a multifaceted disease that results from the complex interaction between genetic and environmental factors. Cancer is a mortal disease with the biggest clinical, societal, and economic burden. Research on better methods of the detection, diagnosis, and treatment of cancer is crucial. Recent advancements in material science have led to the development of metal–organic frameworks, also known as MOFs. MOFs have recently been established as promising and adaptable delivery platforms and target vehicles for cancer therapy. These MOFs have been constructed in a fashion that offers them the capability of drug release that is stimuli-responsive. This feature has the potential to be exploited for cancer therapy that is externally led. This review presents an in-depth summary of the research that has been conducted to date in the field of MOF-based nanoplatforms for cancer therapeutics.

Microfluidic Synthesis of the Tumor Microenvironment-Responsive Nanosystem for Type-I Photodynamic Therapy

Type I photosensitizers with aggregation-induced emission luminogens (AIE-gens) have the ability to generate high levels of reactive oxygen species (ROS), which have a good application prospect in cancer photodynamic therapy (PDT). However, the encapsulation and delivery of AIE molecules are unsatisfactory and seriously affect the efficiency of a practical therapy. Faced with this issue, we synthesized the metal-organic framework (MOF) in one step using the microfluidic integration technology and encapsulated TBP-2 (an AIE molecule) into the MOF to obtain the composite nanomaterial ZT. Material characterization showed that the prepared ZT had stable physical and chemical properties and controllable size and morphology. After being endocytosed by tumor cells, ZT was degraded in response to the acidic tumor microenvironment (TME), and then TBP-2 molecules were released. After stimulation by low-power white light, a large amount of •OH and H₂O₂ was generated by TBP-2 through type I PDT, thereby achieving a tumor-killing effect. Further in vitro cell experiments showed good biocompatibility of the prepared ZT. To the best of our knowledge, this report is the first on the microfluidic synthesis of multifunctional MOF for type I PDT in response to the TME. Overall, the preparation of ZT by the microfluidic synthesis method provides new insight into cancer therapy.

Synthesis of dual-stimuli responsive metal organic framework-coated iridium oxide nanocomposite functionalized with tumor targeting albumin-folate for synergistic photodynamic/photothermal cancer therapy

The synergistic effects of photothermal therapy (PTT) and photodynamic therapy (PDT) has attracted considerable attention in the field of cancer therapy because of its excellent anti-tumor effect. This work provides a novel pH/NIR responsive therapeutic nanoplatform, IrO₂@ZIF-8/BSA-FA (Ce6), producing a synergistic effect of PTT-PDT in the treatment of osteosarcoma. Iridium dioxide nanoparticles (IrO₂ NPs) with exceptional catalase-like activity and PTT effects were synthesized by a hydrolysis method and decorated with zeolitic imidazolate framework-8 (ZIF-8) shell layer to promote the physical absorption of Chlorin e6 (Ce6), and further functionalized with bovine serum albumin-folate acid (BSA-FA) for targeting tumor cells. The IrO₂@ZIF-8/BSA-FA nanocomposite indicated an outstanding photothermal heating conversion efficiency of 62.1% upon laser irradiation. In addition, the Ce6 loading endows nanoplatform with the capability to induce cell apoptosis under 660 nm near-infrared (NIR) laser irradiation through a reactive oxygen species (ROS)-mediated mechanism. It was further testified that IrO₂@ZIF-8/BSA-FA can function as a catalase and convert the endogenous hydrogen peroxide (H₂O₂) into oxygen (O₂) to improve the local oxygen pressure under the acidic tumor microenvironment (TME), which could subsequently amplified PDT-mediated ROS cell-killing performance via relieving hypoxia microenvironment of tumor. Both in vitro and in vivo experimental results indicated that the nanomaterials were good biocompatibility, and could remarkably achieve tumor-specific and enhanced combination therapy outcomes as compared with the corresponding PTT or PDT monotherapy. Taken together, this work holds great potential to design an intelligent multifunctional therapeutic nanoplatform for cancer therapy.

Nanoscale MOFs: From synthesis to drug delivery and theranostics applications

Since the first report in 1989, Metal-Organic Frameworks (MOFs) self-assembled from metal ions or clusters, as well as organic linkers, have attracted extensive attention. Due to their flexible composition, large surface areas, modifiable surface properties, and their degradability, there has been an exponential increase in the study of MOFs materials, specifically in drug delivery system areas such as infection, diabetes, pulmonary disease, ocular disease, imaging, tumor therapy, and especially cancer theranostics. In this review, we discuss the trends in MOFs biosafety, from "green" synthesis to applications in drug delivery systems. Firstly, we present the different "green" synthesis approaches used to prepare MOFs materials. Secondly, we detail the methods for the functional coating, either through grafting targeting units, poly(ethylene glycol) (PEG) chains or by using cell membranes. Then, we discuss drug encapsulation strategies, host-guest interactions, as well as drug release mechanisms. Lastly, we report on the drug delivery applications of nanoscale MOFs. In particular, we discuss MOFs-based imaging techniques, including magnetic resonance imaging (MRI), photoacoustic imaging (PAI), positron emission tomography (PET), and fluorescence imaging. MOFs-based cancer therapy methods are also presented, such as photothermal therapy (PTT), photodynamic therapy (PDT), radiotherapy (RT), chemotherapy, and immunotherapy.

Monitoring Stress Response Difference in Nucleolus Morphology and ATP Content Changes during Hyperthermia Cell Apoptosis with Plasmonic Fluorescent Nanoprobes

The nucleolus, as a main "cellular stress receptor", is the hub of the stress response driving cancer development and has great research value in the field of organelle-targeting photothermal therapy. However, there are few studies focused on monitoring nucleolar stress response and revealing how the energy metabolism of cells regulates the nucleolar stress response during photothermal therapy. Herein, by designing a nucleolus-targeting and ATP- and photothermal-responsive plasmonic fluorescent nanoprobe (AuNRs-CDs) based on gold nanorods (AuNRs) and fluorescent carbon quantum dots (CDs), we achieved real-time fluorescence imaging of nucleus morphology while monitoring changes of ATP content at the subcellular level. We found that the green fluorescence diminished at 5 min of photothermal therapy, and the nucleolus morphology began to shrink and became smaller in cancerous HepG2 cells. In contrast, there is no significant change of green fluorescence in the nucleolar region of normal HL-7702 cells. ATP content monitoring also showed similar results. Apparently, in response to photothermal stimuli, cancerous cells produce more ATP (energy) along with obvious change in nucleolus morphology and state compared to normal cells under the hyperthermia-induced cell apoptosis. The developed AuNRs-CDs as a nucleolus imaging nanoprobe and effective photothermal agent present promising applications for nucleolar stress studies and targeted photothermal therapy.

High Drug-Loading Nanomedicines for Tumor Chemo-Photo Combination Therapy: Advances and Perspectives

The combination of phototherapy and chemotherapy (chemo−photo combination therapy) is an excellent attempt for tumor treatment. The key requirement of this technology is the high drug-loading nanomedicines, which can load either chemotherapy drugs or phototherapy agents at the same nanomedicines and simultaneously deliver them to tumors, and play a multimode therapeutic role for tumor treatment. These nanomedicines have high drug-loading efficiency (>30%) and good tumor combination therapeutic effect with important clinical application potential. Although there are many reports of high drug-loading nanomedicines for tumor therapy at present, systematic analyses on those nanomedicines remain lacking and a comprehensive review is urgently needed. In this review, we systematically analyze the current status of developed high drug-loading nanomedicines for tumor chemo−photo combination therapy and summarize their types, methods, drug-loading properties, in vitro and in vivo applications. The shortcomings of the existing high drug-loading nanomedicines for tumor chemo−photo combination therapy and the possible prospective development direction are also discussed. We hope to attract more attention for researchers in different academic fields, provide new insights into the research of tumor therapy and drug delivery system and develop these nanomedicines as the useful tool for tumor chemo−photo combination therapy in the future.

Multifunctional Gold Nanoparticles in Cancer Diagnosis and Treatment

Cancer is the second leading cause of death in the world, behind only cardiovascular diseases, and is one of the most serious diseases threatening human health nowadays. Cancer patients’ lives are being extended by the use of contemporary medical technologies, such as surgery, radiotherapy, and chemotherapy. However, these treatments are not always effective in extending cancer patients’ lives. Simultaneously, these approaches are often accompanied with a series of negative consequences, such as the occurrence of adverse effects and an increased risk of relapse. As a result, the development of a novel cancer-eradication strategy is still required. The emergence of nanomedicine as a promising technology brings a new avenue for the circumvention of limitations of conventional cancer therapies. Gold nanoparticles (AuNPs), in particular, have garnered extensive attention due to their many specific advantages, including customizable size and shape, multiple and useful physicochemical properties, and ease of functionalization. Based on these characteristics, many therapeutic and diagnostic applications of AuNPs have been exploited, particularly for malignant tumors, such as drug and nucleic acid delivery, photodynamic therapy, photothermal therapy, and X-ray-based computed tomography imaging. To leverage the potential of AuNPs, these applications demand a comprehensive and in-depth overview. As a result, we discussed current achievements in AuNPs in anticancer applications in a more methodical manner in this review. Also addressed in depth are the present status of clinical trials, as well as the difficulties that may be encountered when translating some basic findings into the clinic, in order to serve as a reference for future studies.

Nanofiber-mediated sequential photothermal antibacteria and macrophage polarization for healing MRSA-infected diabetic wounds

Background

Diabetic wound healing remains a challenge because of its susceptibility to drug-resistant bacterial infection and its persistent proinflammatory state. Switching from proinflammatory M1 macrophages (Mφs) to proregenerative M2 dominant Mφs in a timely manner accelerates wound healing by coordinating inflammatory, proliferative, and angiogenic processes.

Methods

We propose a sequential photothermal antibacterial and subsequent M2 Mφ polarization strategy based on nanofibers (NFs) consisting of polydopamine (PDA) coating on curcumin (Cur) nanocrystals to treat Methicillin-resistant Staphylococcus aureus (MRSA)-infected diabetic wounds.

Results

The PDA/Cur NFs showed excellent photothermal conversion and antibacterial effects due to the PDA shell under laser irradiation, consequently resulting in the release of the inner Cur with the ability to promote cell proliferation and reinforce the M2 Mφ phenotype in vitro. In vivo studies on MRSA-infected diabetic wounds showed that PDA/Cur NFs not only inhibited MRSA infection but also accelerated the wound regeneration process. Furthermore, the NFs displayed the ability to promote the M2 Mφ phenotype with enhanced collagen deposition, angiogenesis, and cell proliferation.

Conclusion

Overall, the NFs displayed great potential as promising therapeutics for healing infected diabetic wounds through a sequential photothermal antibacterial and M2 Mφ polarization strategy.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-021-01152-4.

Mitochondria-targeted accumulation of oxygen-irrelevant free radicals for enhanced synergistic low-temperature photothermal and thermodynamic therapy

BACKGROUND

Although lower temperature (< 45 °C) photothermal therapy (LPTT) have attracted enormous attention in cancer therapy, the therapeutic effect is still unsatisfying when applying LPTT alone. Therefore, combining with other therapies is urgently needed to improve the therapeutic effect of LPTT. Recently reported oxygen-irrelevant free radicals based thermodynamic therapy (TDT) exhibit promising potential for hypoxic tumor treatment. However, overexpression of glutathione (GSH) in cancer cells would potently scavenge the free radicals before their arrival to the specific site and dramatically diminish the therapeutic efficacy.

METHODS AND RESULTS

In this work, a core-shell nanoplatform with an appropriate size composed of arginine-glycine-aspartate (RGD) functioned polydopamine (PDA) as a shell and a triphenylphosphonium (TPP) modified hollow mesoporous manganese dioxide (H-mMnO2) as a core was designed and fabricated for the first time. This nanostructure endows a size-controllable hollow cavity mMnO2 and thickness-tunable PDA layers, which effectively prevented the pre-matured release of encapsulated azo initiator 2,2'-azobis[2-(2-imidazolin-2-yl) propane] dihydrochloride (AIBI) and revealed pH/NIR dual-responsive release performance. With the mitochondria-targeting ability of TPP, the smart nanocomposites (AIBI@H-mMnO2-TPP@PDA-RGD, AHTPR) could efficiently induce mitochondrial associated apoptosis in cancer cells at relatively low temperatures (< 45 °C) via selectively releasing oxygen-irrelevant free radicals in mitochondria and facilitating the depletion of intracellular GSH, exhibiting the advantages of mitochondria-targeted LPTT/TDT. More importantly, remarkable inhibition of tumor growth was observed in a subcutaneous xenograft model of osteosarcoma (OS) with negligible side effects.

CONCLUSIONS

The synergistic therapy efficacy was confirmed by effectively inducing cancer cell death in vitro and completely eradicating the tumors in vivo. Additionally, the excellent biosafety and biocompatibility of the nanoplatforms were confirmed both in vitro and in vivo. Taken together, the current study provides a novel paradigm toward oxygen-independent free-radical-based cancer therapy, especially for the treatment of hypoxic solid tumors.

Organic/Inorganic Self-Assembled Hybrid Nano-Architectures for Cancer Therapy Applications

Since the conceptualization of nanomedicine, numerous nanostructure-mediated drug formulations have progressed into clinical trials for treating cancer. However, recent clinical trial results indicate such kind of drug formulations has a limited improvement on the antitumor efficacy. This is due to the biological barriers associated with those formulations, for example, circulation stability, extravasation efficiency in tumor, tumor penetration ability, and developed multi-drug resistance. When employing for nanomedicine formulations, pristine organic-based and inorganic-based nanostructures have their own limitations. Accordingly, organic/inorganic (O/I) hybrids have been developed to integrate the merits of both, and to minimize their intrinsic drawbacks. In this context, the recent development in O/I hybrids resulting from a self-assembly strategy will be introduced. Through such a strategy, organic and inorganic building blocks can be self-assembled via either chemical covalent bonds or physical interactions. Based on the self-assemble procedure, the hybridization of four organic building blocks including liposomes, micelles, dendrimers, and polymeric nanocapsules with five functional inorganic nanoparticles comprising gold nanostructures, magnetic nanoparticles, carbon-based materials, quantum dots, and silica nanoparticles will be highlighted. The recent progress of these O/I hybrids in advanced modalities for combating cancer, such as, therapeutic agent delivery, photothermal therapy, photodynamic therapy, and immunotherapy will be systematically reviewed.

Molecularly engineered carrier-free co-delivery nanoassembly for self-sensitized photothermal cancer therapy

BACKGROUND

Photothermal therapy (PTT) has been extensively investigated as a tumor-localizing therapeutic modality for neoplastic disorders. However, the hyperthermia effect of PTT is greatly restricted by the thermoresistance of tumor cells. Particularly, the compensatory expression of heat shock protein 90 (HSP90) has been found to significantly accelerate the thermal tolerance of tumor cells. Thus, a combination of HSP90 inhibitor and photothermal photosensitizer is expected to significantly enhance antitumor efficacy of PTT through hyperthermia sensitization. However, it remains challenging to precisely co-deliver two or more drugs into tumors.

METHODS

A carrier-free co-delivery nanoassembly of gambogic acid (GA, a HSP90 inhibitor) and DiR is ingeniously fabricated based on a facile and precise molecular co-assembly technique. The assembly mechanisms, photothermal conversion efficiency, laser-triggered drug release, cellular uptake, synergistic cytotoxicity of the nanoassembly are investigated in vitro. Furthermore, the pharmacokinetics, biodistribution and self-enhanced PTT efficacy were explored in vivo.

RESULTS

The nanoassembly presents multiple advantages throughout the whole drug delivery process, including carrier-free fabrication with good reproducibility, high drug co-loading efficiency with convenient dose adjustment, synchronous co-delivery of DiR and GA with long systemic circulation, as well as self-tracing tumor accumulation with efficient photothermal conversion. As expected, HSP90 inhibition-augmented PTT is observed in a 4T1 tumor BALB/c mice xenograft model.

CONCLUSION

Our study provides a novel and facile dual-drug co-assembly strategy for self-sensitized cancer therapy.