Preparation of novel curcumin-loaded multifunctional nanodroplets for combining ultrasonic development and targeted chemotherapy

Application of high intensity focused ultrasound combined with nanomaterials in anti-tumor therapy

High intensity focused ultrasound (HIFU) has demonstrated its safety, efficacy and noninvasiveness in the ablation of solid tumor. However, its further application is limited by its inherent deficiencies, such as postoperative recurrence caused by incomplete ablation and excessive intensity affecting surrounding healthy tissues. Recent research has indicated that the integration of nanomaterials with HIFU exhibits a promising synergistic effect in tumor ablation. The concurrent utilization of nanomaterials with HIFU can help overcome the limitations of HIFU by improving targeting and ablation efficiency, expanding operation area, increasing operation accuracy, enhancing stability and bio-safety during the process. It also provides a platform for multi-therapy and multi-mode imaging guidance. The present review comprehensively expounds upon the synergistic mechanism between nanomaterials and HIFU, summarizes the research progress of nanomaterials as cavitation nuclei and drug carriers in combination with HIFU for tumor ablation. Furthermore, this review highlights the potential for further exploration in the development of novel nanomaterials that enhance the synergistic effect with HIFU on tumor ablation.

The Evolution and Recent Trends in Acoustic Targeting of Encapsulated Drugs to Solid Tumors: Strategies beyond Sonoporation

Despite recent advancements in ultrasound-mediated drug delivery and the remarkable success observed in pre-clinical studies, no delivery platform utilizing ultrasound contrast agents has yet received FDA approval. The sonoporation effect was a game-changing discovery with a promising future in clinical settings. Various clinical trials are underway to assess sonoporation's efficacy in treating solid tumors; however, there are disagreements on its applicability to the broader population due to long-term safety issues. In this review, we first discuss how acoustic targeting of drugs gained importance in cancer pharmaceutics. Then, we discuss ultrasound-targeting strategies that have been less explored yet hold a promising future. We aim to shed light on recent innovations in ultrasound-based drug delivery including newer designs of ultrasound-sensitive particles specifically tailored for pharmaceutical usage.

Opportunities and Challenges of Switchable Materials for Pharmaceutical Use

Switchable polymeric materials, which can respond to triggering signals through changes in their properties, have become a major research focus for parenteral controlled delivery systems. They may enable externally induced drug release or delivery that is adaptive to in vivo stimuli. Despite the promise of new functionalities using switchable materials, several of these concepts may need to face challenges associated with clinical use. Accordingly, this review provides an overview of various types of switchable polymers responsive to different types of stimuli and addresses opportunities and challenges that may arise from their application in biomedicine.

Synthesis of a targeted, dual pH and redox-responsive nanoscale coordination polymer theranostic against metastatic breast cancer in vitro and in vivo

BACKGROUND

Nanoscale coordination polymers (nCP) have exhibited a great potential in designing of the theranostic platforms in the latest years. However, they have low selectivity for cancerous tissues and require to be modified for becoming effective cancer therapeutics. In this study, a novel nanoscale pH and redox-responsive coordination polymer with high selectivity was synthesized.

METHODS

The nCP was synthesized by iron(III) chloride and dithiodiglycolic acid. After loading the prepared nCP with doxorubicin (DOX), nCP was coated with an amphiphilic copolymer composed of α-tocopheryl succinate-polyethylene glycol (VEP). Next, AS1411 aptamer was decorated on the VEP shell of the DOX-loaded nCP (Apt-VEP-nCP@DOX) to provide a guided drug delivery platform.

RESULTS

The prepared platform demonstrated high DOX loading capacity and pH and redox-responsive DOX release. Apt-VEP-nCP@DOX displayed greater DOX internalization and toxicity towards breast cancer cells of 4T1 and MCF7 compared with that of non-targeted VEP-nCP@DOX. Also, the intravenous injection of Apt-VEP-nCP@DOX (a single dose) considerably suppressed the 4T1 tumor growth in vivo. Moreover, Apt-VEP-nCP@DOX showed outstanding magnetic resonance (MR) imaging capability for 4T1 adenocarcinoma diagnosis in ectopic 4T1 tumor model in mice.

CONCLUSIONS

The developed innovative intelligent Apt-VEP-nCP@DOX could serve as a safe and biocompatible theranostic platform appropriate for further translational purposes against breast cancer.

Phase-shift nanodroplets as an emerging sonoresponsive nanomaterial for imaging and drug delivery applications

Nanodroplets - emerging phase-changing sonoresponsive materials - have attracted substantial attention in biomedical applications for both tumour imaging and therapeutic purposes due to their unique response to ultrasound. As ultrasound is applied at different frequencies and powers, nanodroplets have been shown to cavitate by the process of acoustic droplet vapourisation (ADV), causing the development of mechanical forces which promote sonoporation through cellular membranes. This allows drugs to be delivered efficiently into deeper tissues where tumours are located. Recent reviews on nanodroplets are mostly focused on the mechanism of cavitation and their applications in biomedical fields. However, the chemistry of the nanodroplet components has not been discussed or reviewed yet. In this review, the commonly used materials and preparation methods of nanodroplets are summarised. More importantly, this review provides examples of variable chemistry components in nanodroplets which link them to their efficiency as ultrasound-multimodal imaging agents to image and monitor drug delivery. Finally, the drawbacks of current research, future development, and future direction of nanodroplets are discussed.

Folic acid-functionalized gadolinium-loaded phase transition nanodroplets for dual-modal ultrasound/magnetic resonance imaging of hepatocellular carcinoma

Dual-modal molecular imaging by combining two imaging techniques can provide complementary information for early cancer diagnosis and therapeutic monitoring. In the present manuscript, folic acid (FA)-functionalized gadolinium-loaded nanodroplets (NDs) are introduced as dual-modal ultrasound (US)/magnetic resonance (MR) imaging contrast agents. These phase-change contrast agents (PCCAs) with alginate (Alg) stabilizing shell and a liquid perfluorohexane (PFH) core were successfully synthesized via the nano-emulsion method and characterized. In this regard, mouse hepatocellular carcinoma (Hepa1-6) as target cancer cells and mouse fibroblast (L929) as control cells were used. The in vitro and in vivo cytotoxicity assessments indicated that Gd/PFH@Alg and Gd/PFH@Alg-FA nanodroplets are highly biocompatible. Gd-loaded NDs do not induce organ toxicity, and no significant hemolytic activity in human red blood cells is observed. Additionally, nanodroplets exhibited strong ultrasound signal intensities as well as T₁-weighted MRI signal enhancement with a high relaxivity value of 6.40 mM^-1 s^-1, which is significantly higher than that of the clinical Gadovist contrast agent (r₁ = 4.01 mM^-1 s^-1). Cellular uptake of Gd-NDs-FA by Hepa1-6 cancer cells was approximately 2.5-fold higher than that of Gd-NDs after 12 h incubation. Furthermore, in vivo results confirmed that the Gd-NDs-FA bound selectively to cancer cells and were accumulated in the tumor region. In conclusion, Gd/PFH@Alg-FA nanodroplets have great potential as US/MR dual-modal imaging nanoprobes for the early diagnosis of cancer.

Current advances in ultrasound-combined nanobubbles for cancer-targeted therapy: a review of the current status and future perspectives

The non-specific distribution, non-selectivity towards cancerous cells, and adverse off-target side effects of anticancer drugs and other therapeutic molecules lead to their inferior clinical efficacy. Accordingly, ultrasound-based targeted delivery of therapeutic molecules loaded in smart nanocarriers is currently gaining wider acceptance for the treatment and management of cancer. Nanobubbles (NBs) are nanosize carriers, which are currently used as effective drug/gene delivery systems because they can deliver drugs/genes selectively to target sites. Thus, combining the applications of ultrasound with NBs has recently demonstrated increased localization of anticancer molecules in tumor tissues with triggered release behavior. Consequently, an effective therapeutic concentration of drugs/genes is achieved in target tumor tissues with ultimately increased therapeutic efficacy and minimal side-effects on other non-cancerous tissues. This review illustrates present developments in the field of ultrasound-nanobubble combined strategies for targeted cancer treatment. The first part of this review discusses the composition and the formulation parameters of NBs. Next, we illustrate the interactions and biological effects of combining NBs and ultrasound. Subsequently, we explain the potential of NBs combined with US for targeted cancer therapeutics. Finally, the present and future directions for the improvement of current methods are proposed.

NBs combined with ultrasound demonstrated the ability to enhance the targeting of anticancer agents and improve the efficacy.

Polymeric micelles for anticancer drug delivery

Polymeric micelles have gained interest as novel drug delivery systems for the treatment and diagnosis of cancer, as they offer several advantages over conventional drug therapies. This includes drug targeting to tumor tissue, in vivo biocompatibility and biodegradability, prolonged circulation time, enhanced accumulation, retention of the drug loaded micelle in the tumor and decreased side effects. This article provides an overview on the current state of micellar formulations as nanocarriers for anticancer drugs and their effectiveness in cancer therapeutics, including their clinical status. The type of copolymers used, their physicochemical properties and characterization as well as recent developments in the design of functional polymeric micelles are highlighted. The article also presents the design and outcomes of various types of stimuli-responsive polymeric micelles.

Polymeric micelles for anticancer drug delivery

Polymeric micelles have gained interest as novel drug delivery systems for the treatment and diagnosis of cancer, as they offer several advantages over conventional drug therapies. This includes drug targeting to tumor tissue, in vivo biocompatibility and biodegradability, prolonged circulation time, enhanced accumulation, retention of the drug loaded micelle in the tumor and decreased side effects. This article provides an overview on the current state of micellar formulations as nanocarriers for anticancer drugs and their effectiveness in cancer therapeutics, including their clinical status. The type of copolymers used, their physicochemical properties and characterization as well as recent developments in the design of functional polymeric micelles are highlighted. The article also presents the design and outcomes of various types of stimuli-responsive polymeric micelles.

Low-dose curcuminoid-loaded in dextran nanobubbles can prevent metastatic spreading in prostate cancer cells

Preventing recurrences and metastasis of prostate cancer after prostatectomy by administering adjuvant therapies is quite a controversial issue. In addition to effectiveness, absence of side effects and long term toxicity are mandatory. Curcuminoids (Curc) extracted with innovative techniques and effectively loaded by polymeric nanobubbles (Curc-NBs) satisfy such requirements. Curc-NBs showed stable over 30 d, were effectively internalized by tumor cells and were able to slowly release Curc in a sustained way. Significant biological effects were detected in PC-3 and DU-145 cell lines where Curc-NBs were able to inhibit adhesion and migration, to promote cell apoptosis and to affect cell viability and colony-forming capacity in a dose-dependent manner. Since the favourable effects are already detectable at very low doses, which can be reached at a clinical level, the actual drug concentration can be visualized and monitored by US or MRI, Curc-NBs can be proposed as an effective adjuvant theranostic tool.

Color-coded perfluorocarbon nanodroplets for multiplexed ultrasound and Photoacoustic imaging

Laser-activated perfluorocarbon nanodroplets are an emerging class of phase change, dual-contrast agents that can be utilized in ultrasound and photoacoustic imaging. Through the ability to differentiate subpopulations of nanodroplets via laser activation at different wavelengths of near-infrared light, optically-triggered color-coded perfluorocarbon nanodroplets present themselves as an attractive tool for multiplexed ultrasound and photoacoustic imaging. In particular, laser-activated droplets can be used to provide quantitative spatiotemporal information regarding distinct biological targets, allowing for their potential use in a wide range of diagnos tic and therapeutic applications. In the work presented, laser-activated color-coded perfluorocarbon nanodroplets are synthesized to selectively respond to laser irradiation at corresponding wavelengths. The dynamic ultrasound and photoacoustic signals produced by laser-activated perfluorocarbon nanodroplets are evaluated in situ prior to implementation in a murine model. In vivo, these particles are used to distinguish unique particle trafficking mechanisms and are shown to provide ultrasound and photoacoustic contrast for up to 72 hours within lymphatics. Overall, the conducted studies show that laser-activated color-coded perfluorocarbon nanodroplets are a promising agent for multiplexed ultrasound and photoacoustic imaging.

Polymeric nanodroplets: an emerging trend in gaseous delivery system

Currently, nanotechnology-based products are gaining tremendous interest in the development of nanocarriers for drug delivery and nano-diagnostic devices. Nanodroplets (NDs) emerge as novel carriers for delivery of gases and actives with a wide range of applications in fields of theranostics, drug delivery and diagnostic devices. NDs are multifunctional carriers composed of an outer shell of drug and polymer that encapsulates the inner core of gases and liquid molecules. This review focuses on properties of NDs, mathematical theories, different polymers used in the preparation of NDs, characterisation, animal models, toxicity and applications of NDs. These nanocarriers are advantageous due to their cost-effectiveness and compatibility with both gaseous and liquid core molecules. NDs are increasingly utilised in the field of healthcare due to their properties like large effective surface area for drug loading and target specificity. These nanocarriers are also employed in the treatment of hypoxia, multiple sclerosis and cancer. In the near future, NDs will advance in fields of personalised medicine and precise theranostics.

Microbubble-Mediated Enhanced Delivery of Curcumin to Cervical Cancer Cells

The major bottleneck in the current chemotherapy treatment of cancer is the low bioavailability and high cytotoxicity. Targeted delivery of drug to the cancer cells can reduce the cytotoxicity and increase the bioavailability. In this context, microbubbles are currently being explored as drug-delivery vehicles to effectively deliver drug to the tumors or cancerous cells. Microbubbles when used along with ultrasound can enhance drug uptake and inhibit the growth of tumor cells. Several potential anticancer molecules exhibit poor water solubility, which limits their use in therapeutic applications. Such poorly water soluble molecules can be coadministered with microbubbles or encapsulated within or loaded on the microbubbles surface, to enhance the effectiveness of these molecules against cancer cells. Curcumin is one of such potential anticancer molecules obtained from the rhizome of herbal spice, turmeric. In this work, curcumin-loaded protein microbubbles were synthesized and examined for effective in vitro delivery of curcumin to HeLa cells. Microbubbles in the size range of 1-10 μm were produced using perfluorobutane as core gas and bovine serum albumin (BSA) as shell material and were loaded with curcumin. The amount of curcumin loaded on the microbubble surface was estimated using UV-vis spectroscopy, and the average curcumin loading was found to be ∼54 μM/10⁸ microbubbles. Kinetics of in vitro curcumin release from microbubble surface was also estimated, where a 4-fold increase in the rate of curcumin release was obtained in the presence of ultrasound. Sonication and incubation of HeLa cells with curcumin-loaded BSA microbubbles enhanced the uptake of curcumin by ∼250 times. Further, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay confirmed ∼71% decrease in cell viability when HeLa cells were sonicated with curcumin-loaded microbubbles and incubated for 48 h.

Immunomodulatory activities of curcumin-stabilized silver nanoparticles: Efficacy as an antiretroviral therapeutic

We synthesized and characterized curcumin-stabilized silver nanoparticles (Cur-AgNP) and found them to be 45 nm by dynamic light scattering with a maximum absorbance at 406 nm. We evaluated Cur-AgNP for immunomodulatory activities and their potential as an antiretroviral agent. The antiretroviral effects of Cur-AgNP were determined in ACH-2 cells latently infected with human immunodeficiency virus (HIV)-1. ACH-2 cells, 200,000/ml, were treated with Cur-AgNP for 24-48 h. Expression of HIV-1 LTR and p24, the pro-inflammatory cytokines, IL-1β, TNF-α, and NF-κB was quantitated. Treatment of ACH-2 cells latently infected with HIV-1 with Cur-AgNP produced no toxic effects but significantly inhibited the expression of HIV-1 LTR (-73%, P < 0.01) and p24 (-57%, P < 0.05), IL-1βα (-61%, P < 0.01), TNF-αα (-54%, P < 0.05), IL-6 (-68%, P < 0.01), and NF-κB (-79%, P < 0.0001) as compared to untreated controls. Thus, Cur-AgNP have therapeutic potential as direct antiretroviral agents, as well as having immunomodulatory activities inhibiting the expression of pro-inflammatory mediators induced by infection with HIV-1. Experimental controls, such as curcumin alone, and conventional silver nanoparticles capped with citric acid, produced no similar biological effects. We conclude that treatment of HIV-1 infected cells with Cur-AgNP significantly reduced replication of HIV by inhibition of NF-κB nuclear translocation and the downstream expression of the pro-inflammatory cytokines IL-1β, TNF-α, and IL-6. Subsequent in vivo studies with Cur-AgNP using a humanized mouse model of HIV infection are underway.

Catan-ionic hybrid lipidic nano-carriers for enhanced bioavailability and anti-tumor efficacy of chemodrugs

To date there has not been any report on catan-ionic hybrid lipidic nano-carriers, let alone a report on applying them to deliver insoluble anti-tumor drugs. Catan-ionic hybrid lipidic nano-carriers containing curcumin (CUR-C-HLN) inherit the merits of catan-ionic systems, hybrid lipidic systems and nano-structured carriers (the second-generation substitute of solid lipidic nano-systems). Catan-ionic surfactants increased microvesicle stabilization by producing unordered isometric clusters, enhanced absorptive amount as an inhibitor of enzyme and protein, improved tumor accumulation by cellular endocytosis and membranous fusion; hybrid lipids helped to obtain high drug content and low leakage by forming a less-organized matrix arrangement. CUR-C-HLN favorably changed absorptive and pharmacokinetic properties after oral and/or intravenous administrations; improved cell growth inhibition, apoptotic inducing and anti-invasion effects; enhanced antitumor efficiency and reduced cancerous growth. Catan-ionic hybrid lipidic nano-carriers provide an alternative good choice for effective delivery of anticancerous chemodrugs.

In vitro polyphenol effects on apoptosis: An update of literature data

Polyphenols are secondary plant metabolites which have been studied extensively for their health-promoting properties, and which could also exert pharmacological activities ranging from anti-inflammatory effects, to cytotoxic activity against cancer cells. The main mechanism for programmed cell death is represented by apoptosis, and its dysregulation is involved in the etiopathology of cancer. As such, substances able to induce apoptosis in cancer cells could be used as new anticancer agents. The aim of this paper is to review literature data on the apoptotic effects of polyphenols and the molecular mechanisms through which they induce these effects in cancer cells. In addition, a brief summary of the new delivery forms used to increase the bioavailability, and clinical impact of polyphenols is provided. The studies reported show that many polyphenol rich plant extracts, originating from food and herbal medicine, as well as isolated polyphenols administered individually or in combination, can regulate cell apoptosis primarily through intrinsic and extrinsic mechanisms of action in in vitro conditions. Due to these promising results, the use of polyphenols in the treatment of cancer should therefore be deeply investigated. In particular, because of the low number of clinical trials, further studies are required to evaluate the anticancer activity of polyphenols in in vivo conditions.

Successful in vivo hyperthermal therapy toward breast cancer by Chinese medicine shikonin-loaded thermosensitive micelle

The Chinese traditional medicine Shikonin is an ideal drug due to its multiple targets to tumor cells. But in clinics, improving its aqueous solubility and tumor accumulation is still a challenge. Herein, a copolymer with tunable poly(N-isopropylacrymaide) and polylactic acid block lengths is designed, synthesized, and characterized in nuclear magnetic resonance. The corresponding thermosensitive nanomicelle (TN) with well-defined core-shell structure is then assembled in an aqueous solution. For promoting the therapeutic index, the physical-chemistry properties of TNs including narrow size, low critical micellar concentration, high serum stability, tunable volume phase transition temperature (VPTT), high drug-loading capacity, and temperature-controlled drug release are systematically investigated and regulated through the fine self-assembly. The shikonin is then entrapped in a degradable inner core resulting in a shikonin-loaded thermosensitive nanomicelle (STN) with a VPTT of ~40°C. Compared with small-molecular shikonin, the in vitro cellular internalization and cytotoxicity of STN against breast cancer cells (Michigan Cancer Foundation-7) are obviously enhanced. In addition, the therapeutic effect is further enhanced by the programmed cell death (PCD) specifically evoked by shikonin. Interestingly, both the proliferation inhibition and PCD are synergistically promoted as T > VPTT, namely the temperature-regulated passive targeting. Consequently, as intravenous injection is administered to the BALB/c nude mice bearing breast cancer, the intratumor accumulation of STNs is significantly increased as T > VPTT, which is regulated by the in-house developed heating device. The in vivo antitumor assays against breast cancer further confirm the synergistically enhanced therapeutic efficiency. The findings of this study indicate that STN is a potential effective nanoformulation in clinical cancer therapy.

Polyphenol nanoformulations for cancer therapy: experimental evidence and clinical perspective

Cancer is defined as the abnormal cell growth that can cause life-threatening malignancies with high financial costs for patients as well as the health care system. Natural polyphenols have long been used for the prevention and treatment of several disorders due to their antioxidant, anti-inflammatory, cytotoxic, antineoplastic, and immunomodulatory effects discussed in the literature; thus, these phytochemicals are potentially able to act as chemopreventive and chemotherapeutic agents in different types of cancer. One of the problems regarding the use of polyphenolic compounds is their low bioavailability. Different types of formulations have been designed for the improvement of bioavailability of these compounds, nanonization being one of the most notable approaches among them. This study aimed to review current data on the nanoformulations of natural polyphenols as chemopreventive and chemotherapeutic agents and to discuss their molecular anticancer mechanisms of action. Nanoformulations of natural polyphenols as bioactive agents, including resveratrol, curcumin, quercetin, epigallocatechin-3-gallate, chrysin, baicalein, luteolin, honokiol, silibinin, and coumarin derivatives, in a dose-dependent manner, result in better efficacy for the prevention and treatment of cancer. The impact of nanoformulation methods for these natural agents on tumor cells has gained wider attention due to improvement in targeted therapy and bioavailability, as well as enhancement of stability. Today, several nanoformulations are designed for delivery of polyphenolic compounds, including nanosuspensions, solid lipid nanoparticles, liposomes, gold nanoparticles, and polymeric nanoparticles, which have resulted in better antineoplastic activity, higher intracellular concentration of polyphenols, slow and sustained release of the drugs, and improvement of proapoptotic activity against tumor cells. To conclude, natural polyphenols demonstrate remarkable anticancer potential in pharmacotherapy; however, the obstacles in terms of their bioavailability in and toxicity to normal cells, as well as targeted drug delivery to malignant cells, can be overcome using nanoformulation-based technologies, which optimize the bioefficacy of these natural drugs.

Theranostic Performance of Acoustic Nanodroplet Vaporization-Generated Bubbles in Tumor Intertissue

Solid tumors with poorly perfused regions reveal some of the treatment limitations that restrict drug delivery and therapeutic efficacy. Acoustic droplet vaporization (ADV) has been applied to directly disrupt vessels and release nanodroplets, ADV-generated bubbles (ADV-Bs), and drugs into tumor tissue. In this study, we investigated the in vivo behavior of ADV-Bs stimulated by US, and evaluated the possibility of moving intertissue ADV-Bs into the poorly perfused regions of solid tumors. Intravital imaging revealed intertissue ADV-B formation, movement, and cavitation triggered by US, where the distance of intertissue ADV-B movement was 33-99 µm per pulse. When ADV-Bs were applied to tumor cells, the cell membrane was damaged, increasing cellular permeability or inducing cell death. The poorly perfused regions within solid tumors show enhancement due to ADV-B accumulation after application of US-triggered ADV-B. The intratumoral nanodroplet or ADV-B distribution around the poorly perfused regions with tumor necrosis or hypoxia were demonstrated by histological assessment. ADV-B formation, movement and cavitation could induce cell membrane damage by mechanical force providing a mechanism to overcome treatment limitations in poorly perfused regions of tumors.

Concurrent anti-vascular therapy and chemotherapy in solid tumors using drug-loaded acoustic nanodroplet vaporization

Drug-loaded nanodroplets (NDs) can be converted into gas bubbles through ultrasound (US) stimulation, termed acoustic droplet vaporization (ADV), which provides a potential strategy to simultaneously induce vascular disruption and release drugs for combined physical anti-vascular therapy and chemotherapy. Doxorubicin-loaded NDs (DOX-NDs) with a mean size of 214nm containing 2.48mg DOX/mL were used in this study. High-speed images displayed bubble formation and cell debris, demonstrating the reduction in cell viability after ADV. Intravital imaging provided direct visualization of disrupted tumor vessels (vessel size <30μm), the extravasation distance was 12μm in the DOX-NDs group and increased over 100μm in the DOX-NDs+US group. Solid tumor perfusion on US imaging was significantly reduced to 23% after DOX-NDs vaporization, but gradually recovered to 41%, especially at the tumor periphery after 24h. Histological images of the DOX-NDs+US group revealed tissue necrosis, a large amount of drug extravasation, vascular disruption, and immune cell infiltration at the tumor center. Tumor sizes decreased 22%, 36%, and 68% for NDs+US, DOX-NDs, and DOX-NDs+US, respectively, to prolong the survival of tumor-bearing mice. Therefore, this study demonstrates that the combination of physical anti-vascular therapy and chemotherapy with DOX-NDs vaporization promotes uniform treatment to improve therapeutic efficacy.

STATEMENT OF SIGNIFICANCE

Tumor vasculature plays an important role for tumor cell proliferation by transporting oxygen and nutrients. Previous studies combined anti-vascular therapy and drug release to inhibit tumor growth by ultrasound-stimulated microbubble destruction or acoustic droplet vaporization. Although the efficacy of combined therapy has been demonstrated; the relative spatial distribution of vascular disruption, drug delivery, and accompanied immune responses within solid tumors was not discussed clearly. Herein, our study used drug-loaded nanodroplets to combined physical anti-vascular and chemical therapy. The in vitro cytotoxicity, intravital imaging, and histological assessment were used to evaluate the temporal and spatial cooperation between physical and chemical effect. These results revealed some evidences for complementary action to explain the high efficacy of tumor inhibition by combined therapy.

Polymer-Based Materials in Cancer Treatment: From Therapeutic Carrier and Ultrasound Contrast Agent to Theranostic Applications

The emergence of theranostics with ultrasound technology is a promising development, as it opens pathways to providing more effective treatments for cancer. Advancements in ultrasound imaging would give a more detailed and accurate image for better diagnosis and treatment planning. Polymeric ultrasound contrast agents (UCAs) are appealing because they are stable and easily modified for active targeting. In addition, a better therapy could be achieved in conjunction with advancements in UCAs. The active targeting not only makes the precise imaging possible, but also leads to targeted delivery of active components to specific local treatment sites. A polymeric nanocarrier with surface bioconjugation is the key to prolonging the bioavailability of the encapsulated drugs or genes and the capacity to target the specific tumor site. Using ultrasound with other imaging modalities will open more precise and better ways for diagnosis and therapy and bring us a step closer to personalized medicine. This review focuses on polymer-based materials of UCAs, multimodal imaging agents and therapeutic carriers that have been currently explored for their theranostic applications involving ultrasound for cancer diagnosis and treatment.

Enhancement of Anti-Inflammatory Activity of Curcumin Using Phosphatidylserine-Containing Nanoparticles in Cultured Macrophages

Macrophages are one kind of innate immune cells, and produce a variety of inflammatory cytokines in response to various stimuli, such as oxidized low density lipoprotein found in the pathogenesis of atherosclerosis. In this study, the effect of phosphatidylserine on anti-inflammatory activity of curcumin-loaded nanostructured lipid carriers was investigated using macrophage cultures. Different amounts of phosphatidylserine were used in the preparation of curcumin nanoparticles, their physicochemical properties and biocompatibilities were then compared. Cellular uptake of the nanoparticles was investigated using a confocal laser scanning microscope and flow cytometry analysis in order to determine the optimal phosphatidylserine concentration. In vitro anti-inflammatory activities were evaluated in macrophages to test whether curcumin and phosphatidylserine have interactive effects on macrophage lipid uptake behavior and anti-inflammatory responses. Here, we showed that macrophage uptake of phosphatidylserine-containing nanostructured lipid carriers increased with increasing amount of phosphatidylserine in the range of 0%–8%, and decreased when the phosphatidylserine molar ratio reached over 12%. curcumin-loaded nanostructured lipid carriers significantly inhibited lipid accumulation and pro-inflammatory factor production in cultured macrophages, and evidently promoted release of anti-inflammatory cytokines, when compared with curcumin or phosphatidylserine alone. These results suggest that the delivery system using PS-based nanoparticles has great potential for efficient delivery of drugs such as curcumin, specifically targeting macrophages and modulation of their anti-inflammatory functions.

Multimodal micro, nano, and size conversion ultrasound agents for imaging and therapy

Ultrasound (US) is one of the most commonly used clinical imaging techniques. However, the use of US and US-based intravenous agents extends far beyond imaging. In particular, there has been a surge in the fabrication of multimodality US contrast agents and theranostic US agents for cancer imaging and therapy. The unique interaction of US waves with microscale and nanoscale agents has attracted much attention in the development of contrast agents and drug-delivery vehicles. The dimensions of the agent not only dictate how it behaves in vivo, but also how it interacts with US for imaging and drug delivery. Furthermore, these agents are also unique due to their ability to convert from the nanoscale to the microscale and vice versa, having imaging and therapeutic utility in both dimensions. Here, we review multimodality and multifunctional US-based agents, according to their size, and also highlight recent developments in size conversion US agents. WIREs Nanomed Nanobiotechnol 2016, 8:796-813. doi: 10.1002/wnan.1398 For further resources related to this article, please visit the WIREs website.

Nanobubbles: a promising efficienft tool for therapeutic delivery

In recent decades ultrasound-guided delivery of drugs loaded on nanocarriers has been the focus of increasing attention to improve therapeutic treatments. Ultrasound has often been used in combination with microbubbles, micron-sized spherical gas-filled structures stabilized by a shell, to amplify the biophysical effects of the ultrasonic field. Nanometer size bubbles are defined nanobubbles. They were designed to obtain more efficient drug delivery systems. Indeed, their small sizes allow extravasation from blood vessels into surrounding tissues and ultrasound-targeted site-specific release with minimal invasiveness. Additionally, nanobubbles might be endowed with improved stability and longer residence time in systemic circulation. This review will describe the physico-chemical properties of nanobubbles, the formulation parameters and the drug loading approaches, besides potential applications as a therapeutic tool.

Recent advances in polymeric micelles for anti-cancer drug delivery

Block co-polymeric micelles receive increased attention due to their ability to load therapeutics, deliver the cargo to the site of action, improve the pharmacokinetic of the loaded drug and reduce off-target cytotoxicity. While polymeric micelles can be developed with improved drug loading capabilities by modulating hydrophobicity and hydrophilicity of the micelle forming block co-polymers, they can also be successfully cancer targeted by surface modifying with tumor-homing ligands. However, maintenance of the integrity of the self-assembled system in the circulation and disassembly for drug release at the site of drug action remain a challenge. Therefore, stimuli-responsive polymeric micelles for on demand drug delivery with minimal off-target effect has been developed and extensively investigated to assess their sensitivity. This review focuses on discussing various polymeric micelles currently utilized for the delivery of chemotherapeutic drugs. Designs of various stimuli-sensitive micelles that are able to control drug release in response to specific stimuli, either endogenous or exogenous have been delineated.

Pharmacokinetics of quercetin-loaded nanodroplets with ultrasound activation and their use for bioimaging

Bubble formulations have both diagnostic and therapeutic applications. However, research on nanobubbles/nanodroplets remains in the initial stages. In this study, a nanodroplet formulation was prepared and loaded with a novel class of chemotherapeutic drug, ie, quercetin, to observe its pharmacokinetic properties and ultrasonic bioimaging of specific sites, namely the abdominal vein and bladder. Four parallel groups were designed to investigate the effects of ultrasound and nanodroplets on the pharmacokinetics of quercetin. These groups were quercetin alone, quercetin triggered with ultrasound, quercetin-encapsulated in nanodroplets, and quercetin encapsulated in nanodroplets triggered with ultrasound. Spherical vesicles with a mean diameter of 280 nm were formed, and quercetin was completely encapsulated within. In vivo ultrasonic imaging confirmed that the nanodroplets could be treated by ultrasound. The results indicate that the initial 5-minute serum concentration, area under the concentration–time curve, elimination half-life, and clearance of quercetin were significantly enhanced by nanodroplets with or without ultrasound.

Dissecting the role of curcumin in tumour growth and angiogenesis in mouse model of human breast cancer

Breast cancer is considered the most common cancer for women worldwide and it is now the second leading cause of cancer-related deaths among females in the world. Since breast cancer is highly resistant to chemotherapy, alternative anticancer strategies have been developed. In particular, many studies have demonstrated that curcumin, a derivative of turmeric, can be used as natural agent in treatment of some types of cancer by playing antiproliferative and antioxidant effects. In our study, we assessed the antitumor activities of curcumin in ER-negative human breast cancer cell line resistant to chemotherapy, MDA.MB231 by in vitro and in vivo experiments. In vitro data allowed us to demonstrate that curcumin played a role in regulation of proliferation and apoptosis in MDA.MB231 cells. In vivo, by generation of mouse model of breast cancer, we showed that treatment of curcumin inhibited tumor growth and angiogenesis. Specifically, we showed that curcumin is able to deregulate the expression of cyclin D1, PECAM-1, and p65, which are regulated by NF-κB. Our data demonstrated that curcumin could be used as an adjuvant agent to chemotherapy in treatment of triple negative breast cancer.

Nanonization of curcumin by antisolvent precipitation: process development, characterization, freeze drying and stability performance

The present work aims to investigate applicability of antisolvent precipitation method for preparation of nanosized curcumin and to control their characteristics by determining the influence of process and solvents on solid-state properties of curcumin nanoparticles. Effects of different experimental parameters on particle size were investigated using dynamic light scattering. Particle morphology was studied using SEM. Drug content in stabilized nanoparticles was determined using HPLC. Residual moisture content after lyophilisation was determined using Karl Fischer method and solid state properties were investigated using DSC, TGA, FTIR and powder-XRD. The resulting product showed a high drug load and contained the drug in amorphous form. The particle diameters of prepared curcumin nanoparticles were found in the range of 100-200 nm. In vitro drug release studies indicated a sustained release profile of curcumin from the nanoparticles. Antisolvent precipitation produced amorphous curcumin nanoparticles whose size and morphology could be controlled using gelatine as stabilizer. Lyophilized curcumin nanoparticles with d-sorbitol as lyoprotectant possessed good redispersibility and showed up to 4 times faster in vitro curcumin release rate than that of unprocessed curcumin. Stability tests (at 2-8°C and ambient conditions) indicated that the product was stable for up to 6 months of storage.

Image-guided interventional therapy for cancer with radiotherapeutic nanoparticles

One of the major limitations of current cancer therapy is the inability to deliver tumoricidal agents throughout the entire tumor mass using traditional intravenous administration. Nanoparticles carrying beta-emitting therapeutic radionuclides that are delivered using advanced image-guidance have significant potential to improve solid tumor therapy. The use of image-guidance in combination with nanoparticle carriers can improve the delivery of localized radiation to tumors. Nanoparticles labeled with certain beta-emitting radionuclides are intrinsically theranostic agents that can provide information regarding distribution and regional dosimetry within the tumor and the body. Image-guided thermal therapy results in increased uptake of intravenous nanoparticles within tumors, improving therapy. In addition, nanoparticles are ideal carriers for direct intratumoral infusion of beta-emitting radionuclides by convection enhanced delivery, permitting the delivery of localized therapeutic radiation without the requirement of the radionuclide exiting from the nanoparticle. With this approach, very high doses of radiation can be delivered to solid tumors while sparing normal organs. Recent technological developments in image-guidance, convection enhanced delivery and newly developed nanoparticles carrying beta-emitting radionuclides will be reviewed. Examples will be shown describing how this new approach has promise for the treatment of brain, head and neck, and other types of solid tumors.