Gold nanoparticle-induced sonosensitization enhances the antitumor activity of ultrasound in colon tumor-bearing mice

New features of edge-selectively hydroxylated graphene nanosheets as NIR-II photothermal agent and sonothermal agent for tumor therapy

Second near-infrared (NIR-II) laser-mediated photothermal therapy and sonothermal therapy using low-intensity focused ultrasound exposure for tumors have attracted increasing attention owing to their ability to penetrate deep tissues and provide noninvasive ablation with high therapeutic efficacy. However, their applications were limited by the shortness of optimal NIR-II photothermal agents and sonothermal agents. In this study, we discovered that the edge-selectively hydroxylated graphene nanosheets (EHG NSs) with excellent water dispersibility and an "intact conjugated plane" were not only an outstanding NIR-II photothermal agent but also an effective sonothermal agent for tumor therapy. EHG NSs were incorporated into an injectable adhesive thermosensitive hydrogel with a characteristic sol-gel phase transition behavior. EHG NSs endowed the injectable hydrogel with an exceptional photothermal effect under the laser irradiation (1064 nm, 1.0 W cm-2) as well as an effective sonothermal effect under ultrasonic exposure (3.0 MHz, 2.1 W cm-2), effectively killing tumor cells in vitro and inhibiting tumor growth after intratumoral injection. Especially, the NIR-II photothermal therapy based on the hybrid hydrogel completely ablated the primary tumors and effectively activated systemic anti-tumor immune responses benefiting from the protein adsorption capacity of the injectable hydrogel, significantly inhibiting the growth of the distal tumors. Collectively, EHG nanosheets loaded in the injectable hydrogel will be a promising "all-rounder" for noninvasive deep penetrating thermotherapy and a potent platform that integrates various therapies.

Nanoparticle-Mediated Hyperthermia and Cytotoxicity Mechanisms in Cancer

Hyperthermia has the potential to damage cancerous tissue by increasing the body temperature. However, targeting cancer cells whilst protecting the surrounding tissues is often challenging, especially when implemented in clinical practice. In this direction, there are data showing that the combination of nanotechnology and hyperthermia offers more successful penetration of nanoparticles in the tumor environment, thus allowing targeted hyperthermia in the region of interest. At the same time, unlike radiotherapy, the use of non-ionizing radiation makes hyperthermia an attractive therapeutic option. This review summarizes the existing literature regarding the use of hyperthermia and nanoparticles in cancer, with a focus on nanoparticle-induced cytotoxicity mechanisms.

Kinetic modelling of ultrasound-triggered chemotherapeutic drug release from the surface of gold nanoparticles

Therapeutic ultrasound can be used to trigger the on-demand release of chemotherapeutic drugs from gold nanoparticles (GNPs). In the previous work, our group achieved doxorubicin (DOX) release from the surface of GNPS under low-intensity pulsed ultrasound (LIPUS) exposure. However, the specific release kinetics of ultrasound-triggered DOX release from GNPs is not known. Here, we present a release kinetics study of DOX from GNPs under ultrasound exposure for the first time. A novel dialysis membrane setup was designed to quantify DOX release from LIPUS-activated GNPs at 37.0 °C and 43.4 °C (hyperthermia temperature range). Contributions of thermal and non-thermal mechanisms of LIPUS-triggered DOX release were also quantified. Non-thermal mechanisms accounted for 40 ± 7% and 34 ± 5% of DOX release for 37.0 °C and 43.4 °C trials, respectively. DOX release under LIPUS exposure was found to follow Korsmeyer-Peppas (K-P) kinetics, suggesting a shift from a Fickian (static) to a non-Fickian (dynamic) release profile with the addition of non-thermal interactions. DOX release was attributed to an anomalous diffusion release mechanism from the GNP surface. A finite element model was also developed to quantify the acoustic radiation force, believed to be the driving force of non-thermal DOX release inside the dialysis bag.

Immunogenic antitumor potential of Prakasine nanoparticles in zebrafish by gene expression stimulation

In this study, non-toxic mercury nanoparticle was synthesized as per "Prakash theory of metal drugs" and nanoparticle's characters has been demonstrated by employing several nanotechnological tools including XPS, XRD, EDAX. The size of the Prakasine nanoparticles (PRK-NP) ranged from 90-100 nm, confirmed using TEM, SEM, DLS and along with zeta potential of -29.5 mV before storage and -8.5 mV after storage. The FTIR provided information regarding the nanoparticle capping and functional groups. The study was further elaborated for determining PRK-NPs toxicity, genotoxicity, in-vivo toxicity, immunological anti-tumour activity, immunogenicity potential, gene expression profiling and confirmed by MTT and apoptosis assays, cancer zebrafish model studies and WBC proliferation assay. PRK-NPs revealed no cytotoxicity where cell viability was observed 99% in L6 mouse fibroblasts and 99% in MCF-7 cell lines. Also, the cell viability was to be 89.47% at a very high concentration of 320 µg/ml in HEK 293 cells. The PRK-NPs significantly reduced the tumour in zebrafish at dose of 90 μg/g by up regulating IL-1α, IL-1β, IL-2-ITK, IL-6, IL-8, IL-12, TNF-α and IFN-γ, and down regulating IL-4, IL-5, IL-10 and TGF-β compared to untreated controls without any adverse effects and toxicity. Thus, the current study beholds anticipation PRK-NPs may play a vital role in therapeutic.

Recent Developments of Inorganic Nanosensitizers for Sonodynamic Therapy

As a noninvasive treatment, sonodynamic therapy (SDT) has been widely used in the treatment of tumors because of its ability to penetrate deep tissue with few side effects. As the key factor of SDT, it is meaningful to design and synthesize efficient sonosensitizers. Compared with organic sonosensitizers, inorganic sonosensitizers can be easily excited by ultrasound. In addition, inorganic sonosensitizers with stable properties, good dispersion, and long blood circulation time, have great development potential in SDT. This review summarizes possible mechanisms of SDT (sonoexcitation and ultrasonic cavitation) in detail. Based on these mechanisms, the design and synthesis of inorganic nanosonosensitizers can be divided into three categories: traditional inorganic semiconductor sonosensitizers, enhanced inorganic semiconductor sonosensitizers, and cavitation-enhanced sonosensitizers. Subsequently, the current efficient construction methods of sonosensitizers are summarized including accelerated semiconductor charge separation and enhanced production of reactive oxygen species through ultrasonic cavitation. Furthermore, the advantages and disadvantages of different inorganic sonosensitizers and detailed strategies are systematically discussed on how to enhance SDT. Hopefully, this review could provide new insights into the design and synthesis of efficient inorganic nano-sonosensitizers for SDT.

A Quantitative Study of Thermal and Non-thermal Mechanisms in Ultrasound-Induced Nano-drug Delivery

OBJECTIVE

The primary objective of this study was to quantify the contributions to drug release for thermal and non-thermal mechanisms in ultrasound-induced release from gold nanoparticles (GNPs) for the first time.

METHODS

We studied doxorubicin (DOX) and curcumin release from the surface of GNPs using two different methods to induce drug release in an ex vivo tissue model: (i) localized tissue heating with a water bath and (ii) low-intensity pulsed ultrasound (LIPUS) exposure. Both methods have similar temperature profiles and can induce the release of both hydrophobic (curcumin) and hydrophilic (DOX) drugs from the surface of GNPs. Quantitative drug release in both cases was compared via fluorescence measurements.

DISCUSSION

The water bath heating method induced drug release using thermal effects only, whereas LIPUS exposure induced drug release used a combination of thermal and non-thermal mechanisms. It was found that there were increases of 70 ± 16% (curcumin) and 127 ± 20% (DOX) in drug release when LIPUS was used to induce drug release (both thermal and non-thermal mechanisms) as compared with the water bath (thermal mechanisms only) mediated release.

CONCLUSION

We determined that non-thermal mechanisms account for 41 ± 3% of curcumin release and 56 ± 4% of DOX release. It was concluded that in our ex vivo tissue model, the non-thermal mechanisms play a significant role in LIPUS-induced drug release from GNP drug carriers and that the contributions of non-thermal mechanisms to drug release depend on the type of anticancer drug loaded on the GNP surface.

Fractionated Sonodynamic Therapy Using Gold@Poly(ortho-aminophenol) Nanoparticles and Multistep Low-Intensity Ultrasound Irradiation to Treat Melanoma Cancer: In Vitro and In Vivo Studies

OBJECTIVE

Cancer treatment using ultrasound irradiation with low intensities along with a sonosensitizer has been found to have significant advantages, such as high penetration depth in tissues, non-invasive therapeutic character, minor side effects, good patient adherence and preferential tumor area treatment. In the present study, gold nanoparticles covered by poly(ortho-aminophenol) (Au@POAP NPs) were synthesized and characterized as a new sonosensitizer.

METHODS

We investigated Au@POAP NPs efficacy on fractionated ultrasound irradiation for treatment of melanoma cancer in vitro as well as in vivo.

DISCUSSION

In vitro examinations revealed that although Au@POAP NPs (with a mean size of 9.8 nm) alone represented concentration-dependent cytotoxicity against the B16/F10 cell line, multistep ultrasound irradiation (1 MHz frequency, 1.0 W/cm² intensity, 60 s irradiation time) of the cells in the attendance of Au@POAP NPs led to efficient cell sonodynamic therapy (SDT) and death. Histological analyses revealed that in vivo fractionated SDT toward melanoma tumors of male balb/c mice led to no residual viable tumor cell after 10 d.

CONCLUSION

A deep sonosensitizing effectiveness of Au@POAP NPs on fractionated low-intensity ultrasound irradiation was attained with the main mechanism of tumor cell eradication of promotion of apoptosis or necrosis through dramatically increased reactive oxygen species levels.

Chemo-radiation therapy of U87-MG glioblastoma cells using SPIO@AuNP-Cisplatin-Alginate nanocomplex

Megavoltage radiotherapy and cisplatin-based chemotherapy are the primary glioblastoma treatments. Novel nanoparticles have been designed to reduce adverse effects and boost therapeutic effectiveness. In the present study, we synthesized the SPIO@AuNP-Cisplatin-Alginate (SACA) nanocomplex, composed of a SPIO core, a gold shell, and an alginate coating. SACA was characterized using transmission electron microscopy (TEM) and dynamic light scattering (DLS). U87-MG human glioblastoma cells and the HGF cell line (a healthy primary gingival fibroblast) were treated in multiple groups by a combination of SACA, cisplatin, and 6 MV X-ray. The MTT assay was used to assess the cytotoxicity of cisplatin and SACA (at various concentrations and for 4 h). Following the treatments, apoptosis and cell viability were evaluated in each treatment group using flow cytometry and the MTT assay, respectively. The findings demonstrated that the combination of SACA and 6 MV X-rays (at the doses of 2 and 4 Gy) drastically decreased the viability of U87MG cells, whereas the viability of HGF cells remained unchanged. Moreover, U87MG cells treated with SACA in combination with radiation exhibited a significant increase in apoptosis, demonstrating that this nanocomplex effectively boosted the radiosensitivity of cancer cells. Even though additional in vivo studies are needed, these findings suggest that SACA might be used as a radiosensitizer nanoparticle in the therapy of brain tumors.

Ultrasound-mediated nano drug delivery for treating cancer: Fundamental physics to future directions

The application of biocompatible nanocarriers in medicine has provided several benefits over conventional treatment methods. However, achieving high treatment efficacy and deep penetration of nanocarriers in tumor tissue is still challenging. To address this, stimuli-responsive nano-sized drug delivery systems (DDSs) are an active area of investigation in delivering anticancer drugs. While ultrasound is mainly used for diagnostic purposes, it can also be applied to affect cellular function and the delivery/release of anticancer drugs. Therapeutic ultrasound (TUS) has shown potential as both a stand-alone anticancer treatment and a method to induce targeted drug release from nanocarrier systems. TUS approaches have been used to overcome various physiological obstacles, including endothelial barriers, the tumor microenvironment (TME), and immunological hurdles. Combining nanomedicine and ultrasound as a smart DDS can increase in situ drug delivery and improve access to impermeable tissues. Furthermore, smart DDSs can perform targeted drug release in response to distinctive TMEs, external triggers, or dual/multi-stimulus. This results in enhanced treatment efficacy and reduced damage to surrounding healthy tissue or organs at risk. Integrating DDSs and ultrasound is still in its early stages. More research and clinical trials are required to fully understand ultrasound's underlying physical mechanisms and interactions with various types of nanocarriers and different types of cells and tissues. In the present review, ultrasound-mediated nano-sized DDS, specifically focused on cancer treatment, is presented and discussed. Ultrasound interaction with nanoparticles (NPs), drug release mechanisms, and various types of ultrasound-sensitive NPs are examined. Additionally, in vitro, in vivo, and clinical applications of TUS are reviewed in light of the critical challenges that need to be considered to advance TUS toward an efficient, secure, straightforward, and accessible cancer treatment. This study also presents effective TUS parameters and safety considerations for this treatment modality and gives recommendations about system design and operation. Finally, future perspectives are considered, and different TUS approaches are examined and discussed in detail. This review investigates drug release and delivery through ultrasound-mediated nano-sized cancer treatment, both pre-clinically and clinically.

Gold nanomaterials for oral cancer diagnosis and therapy: Advances, challenges, and prospects

Early diagnosis and treatment of oral cancer are vital for patient survival. Since the oral cavity accommodates the second largest and most diverse microbiome community after the gut, the diagnostic and therapeutic approaches with low invasiveness and minimal damage to surrounding tissues are keys to preventing clinical intervention-related infections. Gold nanoparticles (AuNPs) are widely used in the research of cancer diagnosis and therapy due to their excellent properties such as surface-enhanced Raman spectroscopy, surface plasma resonance, controlled synthesis, the plasticity of surface morphology, biological safety, and stability. AuNPs had been used in oral cancer detection reagents, tumor-targeted therapy, photothermal therapy, photodynamic therapy, and other combination therapies for oral cancer. AuNPs-based noninvasive diagnosis and precise treatments further reduce the clinical intervention-related infections. This review is focused on the recent advances in research and application of AuNPs for early screening, diagnostic typing, drug delivery, photothermal therapy, radiotherapy sensitivity treatment, and combination therapy of oral cancer. Distinctive reports from the literature are summarized to highlight the latest advances in the development and application of AuNPs in oral cancer diagnosis and therapy. Finally, this review points out the challenges and prospects of possible applications of AuNPs in oral cancer diagnosis and therapy.

Nanomaterials in cancer: Reviewing the combination of hyperthermia and triggered chemotherapy

Nanoparticle mediated hyperthermia has been explored as a method to increase cancer treatment efficacy by heating tumours inside-out. With that purpose, nanoparticles have been designed and their properties tailored to respond to external stimuli and convert the supplied energy into heat, therefore inducing damage to tumour cells. Moreover, the combination of hyperthermia with chemotherapy has been described as a more effective strategy due to the synergy between the high temperature and the drug's effects, also associated with a remote controlled and on-demand drug release. In this review, the methods behind nanoparticle mediated hyperthermia, namely material design, external stimuli response and energy conversion will be discussed and critically analysed. We will address the most relevant studies on hyperthermia and temperature triggered drug release for cancer treatment. Finally, the advantages, difficulties and challenges of this therapeutic strategy will be discussed, while giving insight for future developments.

Determinants of gold nanoparticle interactions with Proteins: Off-Target effect study

Photothermal therapy is one of the promising approaches toward cancer treatment. To date, several compounds have been developed for this application, among which nanoparticles are attracting ever-increasing attention. One of the obstacles in developing efficient photothermal nanoparticle agents is their off-target effect which is mainly mediated via non-specific interactions with proteins. Such interaction not only reduces the bioavailability of the agent but also will cause protein aggregation that can be lethal. So, gaining knowledge on the mechanisms mediating such interactions will facilitate development of more effective agents. Our last studies showed the mechanism of action of two modified gold nanoparticles, folic acid functionalized gold nanoparticles (FA-AuNPs) and gold shelled Fe₃O₄ nanoparticles (AuFeNPs), as photothermal agents. In the current work, we focus on the interaction of these two NPs with human serum albumin (HSA) and human hemoglobin (Hb) as model proteins. The complex formation between NPs and proteins was investigated by fluorescence spectroscopy, dynamic light scattering and circular dichroism. Our data distinguishes the very distinct mode of interaction of charged and neutral NPs with proteins. While the interaction of neutral AuFeNP to proteins is protein dependent, charged nanoparticles FA-AuNP interact indistinguishably with all proteins via electrostatic interactions. Moreover, complexes obtained from FA-AuNPs with proteins are more stable than that of AuFeNP. However, the secondary structure content of proteins in the presence of NPs indicates the insignificant effect of NPs on the secondary structure of these proteins. Our data propose that the charge functionalization of the NPs is an effective way for modulating the interaction of nanoparticles with proteins.

Fe3O4@Au core-shell hybrid nanocomposite for MRI-guided magnetic targeted photo-chemotherapy

The combination of multiple therapeutic and diagnostic functions is fast becoming a key feature in the area of clinical oncology. The advent of nanotechnology promises multifunctional nanoplatforms with the potential to deliver multiple therapeutics while providing diagnostic information simultaneously. In this study, novel iron oxide-gold core-shell hybrid nanocomposites (Fe₃O₄@Au HNCs) coated with alginate hydrogel carrying doxorubicin (DOX) were constructed for targeted photo-chemotherapy and magnetic resonance imaging (MRI). The magnetic core enables the HNCs to be detected through MRI and targeted towards the tumor using an external magnetic field, a method known as magnetic drug targeting (MDT). The Au shell could respond to light in the near-infrared (NIR) region, generating a localized heating for photothermal therapy (PTT) of the tumor. The cytotoxicity assay showed that the treatment of CT26 colon cancer cells with the DOX-loaded HNCs followed by laser irradiation induced a significantly higher cell death as opposed to PTT and chemotherapy alone. The in vivo MRI study proved MDT to be an effective strategy for targeting the HNCs to the tumor, thereby enhancing their intratumoral concentration. The antitumor study revealed that the HNCs can successfully combine chemotherapy and PTT, resulting in superior therapeutic outcome. Moreover, the use of MDT following the injection of HNCs caused a more extensive tumor shrinkage as compared to non-targeted group. Therefore, the as-prepared HNCs could be a promising nanoplatform for image-guided targeted combination therapy of cancer.

Emerging trends in the application of gold nanoformulations in colon cancer diagnosis and treatment

Colorectal cancer is one of the most aggressive types of cancer with about two million new cases and one million deaths in 2020. The side effects of the available chemotherapies and the possibility of developing resistance against treatment highlight the importance of developing new therapeutic options. The development in the field of nanotechnology have introduced the application of nanoparticles (NPs) as a promising approach in the diagnosis and treatments of colorectal cancer and other types of cancer. Gold nanoparticles (AuNPs) are currently one of the most studied materials as they possess unique tunable properties allowing them to play a role in colorectal cancer bioimaging, diagnosis, and therapy. The high surface-to-volume ratio of AuNPs mediates their utilization in drug delivery as well as functionalization to provide specific targeting. Moreover, depending on their physical properties (size, shape), AuNPs can be modified to fit the intended application. However, there are contradictory results around the pharmacokinetics of AuNPs including their biodistribution, clearance, and toxicity. This variation of opinions is most likely due to the development of different AuNPs that vary in shape, size, and surface chemistry, in addition to the conditions under which each research was carried out. The conflicting data represent a challenge in the clinical use of AuNPs suggesting the need to understand the toxicity, fate, and long-term exposure of AuNPs in vivo. Thus, there is an unmet need for the establishment of a publicly available data base for extensive analysis. In this review, we discuss the recent advances in AuNP applications in the treatment and diagnosis of colorectal cancer, mechanisms of action, and clinical challenges.

Mito-Bomb: Targeting Mitochondria for Cancer Therapy

Cancer has been one of the most common life-threatening diseases for a long time. Traditional cancer therapies such as surgery, chemotherapy (CT), and radiotherapy (RT) have limited effects due to drug resistance, unsatisfactory treatment efficiency, and side effects. In recent years, photodynamic therapy (PDT), photothermal therapy (PTT), and chemodynamic therapy (CDT) have been utilized for cancer treatment owing to their high selectivity, minor resistance, and minimal toxicity. Accumulating evidence has demonstrated that selective delivery of drugs to specific subcellular organelles can significantly enhance the efficiency of cancer therapy. Mitochondria-targeting therapeutic strategies are promising for cancer therapy, which is attributed to the essential role of mitochondria in the regulation of cancer cell apoptosis, metabolism, and more vulnerable to hyperthermia and oxidative damage. Herein, the rational design, functionalization, and applications of diverse mitochondria-targeting units, involving organic phosphine/sulfur salts, quaternary ammonium (QA) salts, peptides, transition-metal complexes, guanidinium or bisguanidinium, as well as mitochondria-targeting cancer therapies including PDT, PTT, CDT, and others are summarized. This review aims to furnish researchers with deep insights and hints in the design and applications of novel mitochondria-targeting agents for cancer therapy.

Comprehensive review on ultrasound-responsive theranostic nanomaterials: mechanisms, structures and medical applications

The field of theranostics has been rapidly growing in recent years and nanotechnology has played a major role in this growth. Nanomaterials can be constructed to respond to a variety of different stimuli which can be internal (enzyme activity, redox potential, pH changes, temperature changes) or external (light, heat, magnetic fields, ultrasound). Theranostic nanomaterials can respond by producing an imaging signal and/or a therapeutic effect, which frequently involves cell death. Since ultrasound (US) is already well established as a clinical imaging modality, it is attractive to combine it with rationally designed nanoparticles for theranostics. The mechanisms of US interactions include cavitation microbubbles (MBs), acoustic droplet vaporization, acoustic radiation force, localized thermal effects, reactive oxygen species generation, sonoluminescence, and sonoporation. These effects can result in the release of encapsulated drugs or genes at the site of interest as well as cell death and considerable image enhancement. The present review discusses US-responsive theranostic nanomaterials under the following categories: MBs, micelles, liposomes (conventional and echogenic), niosomes, nanoemulsions, polymeric nanoparticles, chitosan nanocapsules, dendrimers, hydrogels, nanogels, gold nanoparticles, titania nanostructures, carbon nanostructures, mesoporous silica nanoparticles, fuel-free nano/micromotors.

Induction Therapy of Retinoic Acid with a Temozolomide-Loaded Gold Nanoparticle-Associated Ultrasound Effect on Glioblastoma Cancer Stem-Like Colonies

Glioblastoma multiforme (GBM) is the most aggressive glioma. The treatment response is always low, and the condition is typically rapidly fatal. The undifferentiated and self-renewal characteristics of cancer stem cells (CSCs) have been reported, and their potential contribution may cause tumor initiation, recurrence, metastasis, and therapeutic resistance. In particular, glioblastoma stem-like cells exhibit highly invasive properties and drug resistance, serving as a model for the development of novel therapeutic strategies. Induction therapy provides an alternative therapeutic strategy to eliminate the stem cell properties of CSCs and enhance therapeutic sensitivity. The differentiated cells may lose their self-renewal ability, downregulate stem cell-related genes and drug resistance genes, and enhance anticancer drug sensitivity. Therefore, the purpose of this study is to establish a niche for glioblastoma stem-like cell selection as a platform and facilitate the assessment of differentiation therapy on GBM cancer stem-like colonies by retinoic acid (RA) with temozolomide (TMZ)-loaded gold nanoparticles (GNPs) associated with low-intensity ultrasound (LIUS). Herein, a hyaluronic acid-based material system was used to isolate GBM cancer stem-like colonies. Colony formation, size determination, stem cell-related marker expression, and GBM cancer stem-like cell marker expression with the culture period were identified. The effect of TMZ on GBM stem-like colonies on HA-based material systems was also determined, and the results revealed that drug resistance was highly enhanced in GBM colonies compared with that in the control cell population. In addition, GBM colonies also exhibited a significant increase in breast cancer resistance protein expression, which is consistent with the drug resistance effect. Furthermore, several factors, including LIUS, RA, and GNPs, were used to determine the possibility of induction therapy. RA with TMZ-loaded GNP-associated LIUS stimulation exhibited a significant and synergistic effect on the differentiation effect and drug sensitivity enhancement. The GBM cancer stem-like colony system presents an opportunity for the development of new therapeutic strategies, and this study provides an alternative differentiation therapy for malignant tumors.

Ultrasound-Based Drug Delivery System

Cancer still represents a leading threat to human health worldwide. The effective usage of anti-cancer drugs can reduce patients' clinical symptoms and extend the life span. Current anti-cancer strategies include chemotherapy, traditional Chinese medicine, biopharmaceuticals, and the latest targeted therapy. However, due to the complexity and heterogeneity of tumors, serious side effects may result from the direct use of anti-cancer drugs. Besides, the current therapeutic strategies failed to effectively alleviate metastasized tumors. Recently, an ultrasound-mediated nano-drug delivery system has become an increasingly important treatment strategy. Due to its ability to enhance efficacy and reduce toxic side effects, it has become a research hotspot in the field of biomedicine. In this review, we introduced the latest research progress of the ultrasound-responsive nano-drug delivery systems and the possible mechanisms of ultrasound acting on the carrier to change the structure or conformation as well as to realize the controlled release. In addition, the progress in ultrasound responsive nano-drug delivery systems will also be briefly summarized.

Smart Nanoparticles for Chemo-Based Combinational Therapy

Cancer is a heterogeneous and complex disease. Traditional cancer therapy is associated with low therapeutic index, acquired resistance, and various adverse effects. With the increasing understanding of cancer biology and technology advancements, more strategies have been exploited to optimize the therapeutic outcomes. The rapid development and application of nanomedicine have motivated this progress. Combinational regimen, for instance, has become an indispensable approach for effective cancer treatment, including the combination of chemotherapeutic agents, chemo-energy, chemo-gene, chemo-small molecules, and chemo-immunology. Additionally, smart nanoplatforms that respond to external stimuli (such as light, temperature, ultrasound, and magnetic field), and/or to internal stimuli (such as changes in pH, enzymes, hypoxia, and redox) have been extensively investigated to improve precision therapy. Smart nanoplatforms for combinational therapy have demonstrated the potential to be the next generation cancer treatment regimen. This review aims to highlight the recent advances in smart combinational therapy.

Multifunctional Theranostic Graphene Oxide Nanoflakes as MR Imaging Agents with Enhanced Photothermal and Radiosensitizing Properties

The integration of multiple therapeutic and diagnostic functions into a single nanoplatform for image-guided cancer therapy has been an emerging trend in nanomedicine. We show here that multifunctional theranostic nanostructures consisting of superparamagnetic iron oxide (SPIO) and gold nanoparticles (AuNPs) scaffolded within graphene oxide nanoflakes (GO-SPIO-Au NFs) can be used for dual photo/radiotherapy by virtue of the near-infrared (NIR) absorbance of GO for photothermal therapy (PTT) and the Z element radiosensitization of AuNPs for enhanced radiation therapy (RT). At the same time, this nanoplatform can also be detected by magnetic resonance (MR) imaging because of the presence of SPIO NPs. Using a mouse carcinoma model, GO-SPIO-Au NF-mediated combined PTT/RT exhibited a 1.85-fold and 1.44-fold higher therapeutic efficacy compared to either NF-mediated PTT or RT alone, respectively, resulting in a complete eradication of tumors. As a sensitive multifunctional theranostic platform, GO-SPIO-Au NFs appear to be a promising nanomaterial for enhanced cancer imaging and therapy.

Monitoring of the choline/lipid ratio by 1H-MRS can be helpful for prediction and early detection of tumor response to nano-photo-thermal therapy

Nanotechnology-based photothermal therapy (NPTT) is a new emerging modality of cancer therapy. To have the right prediction and early detection of response to NPTT, it is necessary to get rapid feedback from a tumor treated by NPTT procedure and stay informed of what happens in the tumor site. We performed this study to find if proton magnetic resonance spectroscopy (1H-MRS) can be well responsive to such an imperative requirement. We considered various treatment groups including gold nanoparticles (AuNPs), laser, and the combination of AuNPs and laser (NPTT group). Therapeutic effects on CT26 colon tumor-bearing BALB/c mice were studied by looking at alterations that happened in 1H-MRS signals and tumor size after conducting treatment procedures. In MRS studies, the alterations of choline and lipid concentrations and their ratio were investigated. Having normalized the metabolite peak to water peak, we found a significant decrease in choline concentration post-NPTT (from (1.25 ± 0.05) × 10^-3 to (0.43 ± 0.04) × 10^-3), while the level of lipid concentration in the tumor was slightly increased (from (2.91 ± 0.23) × 10^-3 to (3.52 ± 0.31) × 10^-3). As a result, the choline/lipid ratio was significantly decreased post-NPTT (from 0.41 ± 0.11 to 0.11 ± 0.02). Such alterations appeared just 1 day after NPTT. Tumor shrinkage in all groups was studied and significant changes were significantly detectable on day 7 post-NPTT procedure. In conclusion, the study of choline/lipid ratio using 1H-MRS may help us estimate what happens in a tumor treated by the NPTT method. Such an in vivo assessment is interestingly feasible as soon as just 1 day post-NPTT. This would undoubtedly help the oncologists make a more precise decision about treatment planning strategies. Monitoring of the choline/lipid ratio by ¹H-MRS can be helpful for prediction and early detection of response to nano-photo-thermal therapy.

Recent Progresses in Organic-Inorganic Nano Technological Platforms for Cancer Therapeutics

Nanotechnology offers promising tools in interdisciplinary research areas and getting an upsurge of interest in cancer therapeutics. Organic nanomaterials and inorganic nanomaterials bring revolutionary advancement in cancer eradication process. Oncology is achieving new heights under nano technological platform by expediting chemotherapy, radiotherapy, photo thermodynamic therapy, bio imaging and gene therapy. Various nanovectors have been developed for targeted therapy which acts as "Nano-bullets" for tumor cells selectively. Recently combinational therapies are catching more attention due to their enhanced effect leading towards the use of combined organicinorganic nano platforms. The current review covers organic, inorganic and their hybrid nanomaterials for various therapeutic action. The technological aspect of this review emphasizes on the use of inorganic-organic hybrids and combinational therapies for better results and also explores the future opportunities in this field.

Optimal scheduling of the nanoparticle-mediated cancer photo-thermo-radiotherapy

Maximal synergistic effect between photothermal therapy and radiotherapy (RT) may be achieved when the interval between these two modalities is optimal. In this study, we tried to determine the optimal schedule of the combined regime of RT and nano-photothermal therapy (NPTT), based on the cell cycle distribution and kinetics of cell death. To this end, alginate-coated iron oxide-gold core-shell nanoparticles (Fe₃O₄@Au/Alg NPs) were synthesized, characterized, and their photo-radio sensitization potency was evaluated on human nasopharyngeal cancer KB cells. Our results demonstrated that synthesized NPs have a good potential in radiotherapy and near-infrared (NIR) photothermal therapy. However, results from flow cytometry analysis indicated that a major portion of KB cells were accumulated in the most radiosensitive phases of cell cycle (G2/M) 24 h after NPTT. Moreover, the maximal synergistic anticancer efficacy (12.3% cell viability) was observed when RT was applied 24 h following the administration of NPTT (NPs [30 μg/mL, 4 h incubation time] + Laser [808 nm, 1 W/cm², 5 min] + RT [6 Gy]). It is noteworthy that apoptosis was the dominant cell death pathway in the group of cells treated by combination of NPTT and RT. This highly synergistic anticancer efficacy provides a mechanistic basis for Fe₃O₄@Au/Alg NPs-mediated photothermal therapy combined with RT. Knowing such a basis is helpful to promote novel nanotechnology cancer treatment strategies.

Redox-Responsive Self-Assembled Nanoparticles for Cancer Therapy

Chemotherapy, combined with other treatments, is widely applied in the clinical treatment of cancer. However, deficiencies inherited from the traditional route of administration limit its successful application. With the development of nanotechnology, a series of smart nanodelivery systems have been developed to utilize the unique tumor environment (pH changes, different enzymes, and redox potential gradients) and exogenous stimuli (thermal changes, magnetic fields, and light) to improve the curative effect of anticancer drugs. In this review, endogenous and exogenous stimuli are briefly introduced. Among these stimuli, various redox-sensitive linkages are primarily described in detail, and their application with self-assembled nanoparticles is recounted. Finally, the application of redox-responsive self-assembled nanoparticles in cancer therapy is summarized.

Investigation of the Dose-Enhancement Effects of Spherical and Rod-Shaped Gold Nanoparticles on the HeLa Cell Line

Background:

Cervical cancer cells are known as radioresistant cells. Current treatment methods have not improved the patients’ survival efficiently; thus, new therapeutic strategies are needed to enhance the efficacy of radiotherapy. Gold nanomaterials with different shapes and sizes have been explored as radiosensitizers. The present study compared the radiosensitizing effects of gold nanorods (AuNRs) with spherical gold nanoparticles (AuNPs) on the HeLa cell line irradiated with megavoltage X-rays.

Materials and Methods:

The cytotoxicity of AuNRs and AuNPs on HeLa cells in the presence and absence of 6-MV X-ray was investigated using the MTT assay. For this aim, HeLa cells were incubated with and AuNPs and AuNRs at various concentrations (5, 10, and 15 µg/mL) for 6 hours. Afterward, HeLa cells were irradiated with 6-MV X-ray at a single dose of 2 Gy.

Results:

The results showed that the addition of AuNRs and AuNPs could enhance the radiosensitivity of HeLa cells. Both AuNRs and AuNPs showed low toxicity on HeLa cells, while AuNRs were more toxic than AuNPs at the examined concentrations. Moreover, it was found that AuNRs could enhance the radiosensitivity of HeLa cells more than spherical-shaped AuNPs.

Conclusion:

This study revealed that the shape of nanoparticles is an effective factor when they are used as radiosensitizing agents during radiotherapy.

Insights into Nano-Photo-Thermal Therapy of Cancer: The Kinetics of Cell Death and Effect on Cell Cycle

Background:

Despite considerable advances in nano-photo-thermal therapy (NPTT), there have been a few studies reporting in-depth kinetics of cell death triggered by such a new modality of cancer treatment.

Objective:

In this study, we aimed to (1) investigate the cell death pathways regulating the apoptotic responses to NPTT; and (2) ascertain the effect of NPTT on cell cycle progression.

Methods:

Folate conjugated gold nanoparticle (F-AuNP) was firstly synthesized, characterized and then assessed to determine its potentials in targeted NPTT. The experiments were conducted on KB nasopharyngeal cancer cells overexpressing folate receptors (FRs), as the model, and L929 normal fibroblast cells with a low level of FRs, as the control. Cytotoxicity was evaluated by MTT assay and the cell death mode (i.e., necrosis or apoptosis) was determined through AnnexinV/FITC-propidium iodide staining. Next, the gene expression profiles of some key apoptotic factors involved in the mitochondrial signaling pathway were investigated using RT-qPCR. Finally, cell cycle phase distribution was investigated at different time points post NPTT using flow cytometric analysis.

Results:

The obtained results showed that KB cell death following targeted NPTT was greater than that observed for L929 cells. The majority of KB cell death following NPTT was related to apoptosis. RT-qPCR analysis indicated that the elevated expression of Bax along with the depressed expression of Bcl-xL, Survivin and XIAP may involve in the regulation of apoptosis in response to NPTT. Flow cytometric analysis manifested that 16-24 hours after NPTT, the major proportion of KB cells was in the most radiosensitive phases of the cell cycle (G2/M).

Conclusion:

This study extended the understanding of the signaling pathway involved in the apoptotic response to NPTT. Moreover, the potential effect of NPTT on sensitizing cancer cells to subsequent radiation therapy was highlighted.

Triple combination of heat, drug and radiation using alginate hydrogel co-loaded with gold nanoparticles and cisplatin for locally synergistic cancer therapy

Although multimodal cancer therapy has shown superior antitumor efficacy in comparison to individual therapy due to the potential generation of synergistic interactions among the treatments, its clinical usage is highly hampered by systemic dose-limiting toxicities. Herein, we developed a multi-responsive nanocomplex constructed from alginate hydrogel co-loaded with cisplatin and gold nanoparticles (AuNPs) (abbreviated as ACA) to combine chemotherapy, radiotherapy (RT) and photothermal therapy. The nanocomplex markedly improved the efficiency of drug delivery where ACA resulted in noticeably higher tumor growth inhibition than free cisplatin. The tumor treated with ACA showed an increased heating rate upon 532 nm laser irradiation, indicating the photothermal conversion ability of the nanocomplex. While RT alone resulted in slight tumor growth inhibition, thermo-chemo therapy, chemoradiation therapy and thermo-radio therapy using ACA dramatically slowed down the rate of tumor growth. Upon 532 nm laser and 6 MV X-ray, the nanocomplex could enable a trimodal thermo-chemo-radio therapy that yielded complete tumor regression with no evidence of relapse during the 90-days follow up period. The results of this study demonstrated that the incorporation of AuNPs and cisplatin into alginate hydrogel network can effectively combine chemotherapy, RT and photothermal therapy to achieve a locally synergistic cancer therapy.

In vitro Ultrasonic Potentiation of 2-Phenylethynesulfonamide/Magnetic Fluid Hyperthermia Combination Treatments for Ovarian Cancer

Background

Magnetic Fluid Hyperthermia (MFH) is a promising adjuvant for chemotherapy, potentiating the action of anticancer agents. However, drug delivery to cancer cells must be optimized to improve the overall therapeutic effect of drug/MFH combination treatments.

Purpose

The aim of this work was to demonstrate the potentiation of 2-phenylethynesulfonamide (PES) at various combination treatments with MFH, using low-intensity ultrasound as an intracellular delivery enhancer.

Methods

The effect of ultrasound (US), MFH, and PES was first evaluated individually and then as combination treatments. Definity^® microbubbles and polyethylene glycol (PEG)-coated iron oxide nanoparticles were used to induce cell sonoporation and MFH, respectively. Assessment of cell membrane permeabilization was evaluated via fluorescence microscopy, iron uptake by cells was quantified by UV-Vis spectroscopy, and cell viability was determined using automatic cell counting.

Results

Notable reductions in cancer cell viability were observed when ultrasound was incorporated. For example, the treatment US+PES reduced cell viability by 37% compared to the non-toxic effect of the drug. Similarly, the treatment US+MFH using mild hyperthermia (41°C), reduced cell viability by an additional 18% when compared to the effect of MH alone. Significant improvements were observed for the combination of US+PES+MFH with cell viability reduced by an additional 26% compared to the PES+MFH group. The improved cytotoxicity was attributed to enhanced drug/nanoparticle intracellular delivery, with iron uptake values nearly twice those achieved without ultrasound. Various treatment schedules were examined, and all of them showed substantial cell death, indicating that the time elapsed between sonoporation and magnetic field exposure was not significant.

Conclusion

Superior cancer cell-killing patterns took place when ultrasound was incorporated thus demonstrating the in vitro ultrasonic potentiation of PES and mild MFH. This work demonstrated that ultrasound is a promising non-invasive enhancer of PES/MFH combination treatments, aiming to establish a sono-thermo-chemotherapy in the treatment of ovarian cancer.

Development of Drug Dual-Carriers Delivery System with Mitochondria-Targeted and pH/Heat Responsive Capacity for Synergistic Photothermal-Chemotherapy of Ovarian Cancer

PURPOSE

Multifunctional drug delivery systems (DDS) are emerging as a new strategy to highly treat malignant tumors. The aim of this study is to develop a drug dual-carriers delivery system (DDDS) using the natural protein ferritin (FRT) and a nanoscale graphene oxide (NGO) as dual-carriers.

METHODS

The FRT is a pH-sensitive hollow cage protein with disassembly and reassembly properties and the NGO has a large surface area and a photothermal effect by which it can load and release drugs under near-infrared irradiation (NIR). Due to these unique features, the NGO loaded the anticancer drug resveratrol (RSV) and the conjugated mitochondrion targeted molecule IR780 as IR780-NGO-RSV (INR), the first drug delivery platform. Next, the INR was capsulated by FRT to form the DDDS INR@FRT which was applied for synergistic photothermal-chemotherapy of ovarian cancer.

RESULTS

Through a series of characterizations, INR@FRT showed a uniform nanosphere structure and remarkable stability in physiological condition. Heat/pH 5.0 was confirmed to trigger RSV release from the INR@FRT. After taken up by cells, INR@FRT located to the lysosomes where the acidic environment triggered INR release. INR targeted the mitochondrion and released RSV to directly react with organelles, which in turn decreased the mitochondrion membrane potential and caused cell apoptosis. In-vivo experiments showed that INR@FRT combined with NIR irradiation displayed remarkable tumor suppression with a high survival rate after 60 days of treatment. Finally, the biocompatibility of INR@FRT was demonstrated in vitro and in vivo.

CONCLUSION

These results highlight the immense potential of INR@FRT as a type of DDDS for the treatment of tumors.

An Ultrasound Activated Vesicle of Janus Au-MnO Nanoparticles for Promoted Tumor Penetration and Sono-Chemodynamic Therapy of Orthotopic Liver Cancer

Sonodynamic therapy (SDT) has the advantages of high penetration, non-invasiveness, and controllability, and it is suitable for deep-seated tumors. However, there is still a lack of effective sonosensitizers with high sensitivity, safety, and penetration. Now, ultrasound (US) and glutathione (GSH) dual responsive vesicles of Janus Au-MnO nanoparticles (JNPs) were coated with PEG and a ROS-sensitive polymer. Upon US irradiation, the vesicles were disassembled into small Janus Au-MnO nanoparticles (NPs) with promoted penetration ability. Subsequently, GSH-triggered MnO degradation simultaneously released smaller Au NPs as numerous cavitation nucleation sites and Mn²⁺ for chemodynamic therapy (CDT), resulting in enhanced reactive oxygen species (ROS) generation. This also allowed dual-modality photoacoustic imaging in the second near-infrared (NIR) window and T₁ -MR imaging due to the released Mn²⁺ , and inhibited orthotopic liver tumor growth via synergistic SDT/CDT.

Combined thermo-chemotherapy of cancer using 1 MHz ultrasound waves and a cisplatin-loaded sonosensitizing nanoplatform: an in vivo study

PURPOSE

The aim of the present study was to develop a new strategy for combined thermo-chemotherapy of cancer. For this purpose, we used ultrasound waves [1 MHz; 1 W/cm²; 10 min] in combination with a sonosensitizing nanoplatform, named ACA, made of alginate co-loaded with cisplatin and gold nanoparticles (AuNPs).

METHODS

Various combinatorial treatment regimens consisting of ultrasound, AuNPs, cisplatin, and ACA nanoplatform were studied in vivo. The CT26 colon adenocarcinoma cell line was used for tumor induction in BALB/c mice. During the ultrasound exposure, we monitored the temperature variations in each treatment group using infrared thermal imaging. Furthermore, tumor metabolism was assessed by [18F]FDG (2-deoxy-2-[18F]fluoro-D-glucose)-positron emission tomography (PET) imaging.

RESULTS

The combination of ultrasound with nanoplatform showed an improved therapeutic efficacy than free cisplatin or ultrasound alone. It was revealed that the examined thermo-chemotherapy protocol has the potential to intensively decrease the metabolic activity of CT26 tumors.

CONCLUSIONS

The data obtained in this study confirmed a potent anti-tumor efficacy caused by the ACA nanoplatform and ultrasound combination. It may provide a beneficial cancer therapy strategy in which the thermal and mechanical effects of ultrasound can intensify the therapeutic ratio of conventional chemotherapy methods.

The capability of nonlinear optical characteristics as a predictor for cellular uptake of nanoparticles and cell damage

Current methods for determining the cellular effects of a treatment modality need expensive materials and much time to provide a researcher with results. The aim of this study was to evaluate the potential of nonlinear optical characteristics of cancer cells using Z-scan technique to monitor the level of cellular uptake and cell damage caused by a nanotechnology based treatment modality. Two nanocomplexes were synthesized and characterized. The first one was made of alginate hydrogel co-loaded with cisplatin and gold nanoparticles (AuNPs) named as ACA nanocomplex. The second one, named as AA nanocomplex, was the same as ACA, but without cisplatin and this AA nanocomplex was considered as the control for ACA. Different groups of CT26 mouse colon cancer cell line received various treatments of cisplatin, ACA, and AA nanocomplexes and then the samples were prepared for Z-scan studies. The MTT assay was used to evaluate the cytotoxicity induced by different treatment modalities. Transmission electron microscopy (TEM) and inductively coupled plasma-mass spectrometry (ICP-MS) were used for qualitative and quantitative assessments of the level of AuNPs cellular uptake. The trend of nonlinear optical properties changes for treated cells was in agreement with MTT, TEM and ICP-MS results. Z-scan technique was able to successfully indicate the occurrence of cell damage. It was also capable to determine the intensity of cell damage induced by ACA nanocomplex in comparison to free cisplatin. Furthermore, Z-scan results showed that it was able to discriminate the differences of optical properties of the cells incubated with ACA nanocomplex for various incubation times. Nonlinear optical characteristics of a cell may be considered as a reliable indicator to predict the level of cellular effects induced by a nanotechnology based treatment modality. The protocol suggested in this article does not waste materials, not take much time to provide the results, and it is inexpensive technique.

Selective radiofrequency ablation of tumor by magnetically targeting of multifunctional iron oxide-gold nanohybrid

PURPOSE

Radiofrequency (RF) ablation therapy is of great interest in cancer therapy as it is non-ionizing radiation and can effectively penetrate into the tissue. However, the current RF ablation technique is invasive that requires RF probe insertion into the tissue and generates a non-specific heating. Recently, RF-responsive nanomaterials such as gold nanoparticles (AuNPs) and iron oxide nanoparticles (IONPs) have led to tremendous progress in this area. They have been found to be able to absorb the RF field and induce a localized heating within the target, thereby affording a non-invasive and tumor-specific RF ablation strategy. In the present study, for the first time, we used a hybrid core-shell nanostructure comprising IONPs as the core and AuNPs as the shell (IO@Au) for targeted RF ablation therapy. Due to the magnetic core, the nanohybrid can be directed toward the tumor through a magnet. Moreover, IONPs enable the nanohybrid to be used as a magnetic resonance imaging (MRI) contrast agent.

RESULTS

In vitro cytotoxicity experiment showed that the combination of IO@Au and 13.56-MHz RF field significantly reduced the viability of cancer cells. Next, during an in vivo experiment, we demonstrated that magnetically targeting of IO@Au to the tumor and subsequent RF exposure dramatically suppressed the tumor growth.

CONCLUSION

Therefore, the integration of targeting, imaging, and therapeutic performances into IO@Au nanohybrid could afford the promise to improve the effectiveness of RF ablation therapy.

A literature review on multimodality molecular imaging nanoprobes for cancer detection

Molecular imaging techniques using nanoparticles have significant potential to be widely used for the detection of various types of cancers. Nowadays, there has been an increased focus on developing novel nanoprobes as molecular imaging contrast enhancement agents in nanobiomedicine. The purpose of this review article is to summarize the use of a variety of nanoprobes and their current achievements in accurate cancer imaging and effective treatment. Nanoprobes are rapidly becoming potential tools for cancer diagnosis by using novel molecular imaging modalities such as Ultrasound (US) imaging, Computerized Tomography (CT), Single Photon Emission Tomography (SPECT) and Positron Emission Tomography (PET), Magnetic Resonance Imaging (MRI), and Optical Imaging. These imaging modalities may facilitate earlier and more accurate diagnosis and staging the most of cancers.

Iron oxide-gold core-shell nano-theranostic for magnetically targeted photothermal therapy under magnetic resonance imaging guidance

Recent efforts in the area of photothermal therapy (PTT) follow two important aims: (i) selective targeting of plasmonic nanoparticles to the tumor and (ii) real-time guidance of PTT operation through employing multimodal imaging modalities. In the present study, we utilized a multifunctional theranostic nanoplatform constructed from iron (III) oxide-gold (Fe₂O₃@Au) core-shell nanoparticles to fulfill these aims. The Au shell exhibits surface plasmon resonance, a property that is exploited to realize PTT. The magnetic core enables Fe₂O₃@Au to be employed as a magnetic resonance imaging (MRI) contrast agent. Furthermore, the magnetic core has the potential to establish a magnetic drug targeting strategy through which Fe₂O₃@Au can be directed to the tumor site by means of magnetic field. To test these potentials, Balb/c mice bearing CT26 colorectal tumor model were intravenously injected with Fe₂O₃@Au. Immediately after injection, a magnet was placed on the tumor site for 3 h to concentrate nanoparticles, followed by the near infrared (NIR) laser irradiation. MRI study confirmed the accumulation of nanoparticles within the tumor due to T2 enhancement capability of Fe₂O₃@Au. The in vivo thermometry results demonstrated that the tumors in magnetic targeting group had a significantly higher temperature elevation rate upon NIR irradiation than non-targeted group (~ 12 °C vs. 8.5 °C). The in vivo antitumor assessment revealed that systemic injection of Fe₂O₃@Au in combination with magnetic targeting and NIR irradiation resulted in complete remission of tumor growth. Therefore, Fe₂O₃@Au can establish a targeted PTT strategy for efficient eradication of tumor cells under the guidance of MRI.