Biomaterial scaffolds for non-invasive focal hyperthermia as a potential tool to ablate metastatic cancer cells

Enhancing electroporation-induced liposomal drug release in suspension and solid phases

When exposed to an external electric field, lipid bilayer membranes are subject to increased permeability through the generation of pores. Combining this phenomenon, known as electroporation, with liposomal drug delivery offers the added benefit of on-demand release of the liposomal cargo. In previous studies, the maximum percent drug release when exposing liposomes to a pulsed electric field has not surpassed 30%, indicating most of the drug is still retained in the liposomes. Here we showed that by modulating the fluidity of the liposome membrane through appropriate selection of the primary lipid, as well as the addition of other fluidity modulating components such as cholesterol and biotinylated lipid, the electroporation-induced percent release could be increased to over 50%. In addition to improved induced release from liposomes in suspension, biomaterial scaffold-bound liposomes were developed. Electroporation-induced protein release from this solid phase was verified after performing further optimization of the liposome formulation to achieve increased stability at physiological temperatures. Collectively, this work advances the ability to achieve efficient electroporation-induced liposomal drug delivery, which has the potential to be used in concert with other clinical applications of electroporation, such as gene electrotransfer and irreversible electroporation (IRE), in order to synergistically increase treatment efficacy.

Photothermal therapeutic potency of plasmonic silver nanoparticles for apoptosis and anti-angiogenesis in testosterone induced benign prostate hyperplasia in rats

AIMS

In this study, we used a near-infrared laser (NIR) to increase the potency of silver nanoparticles (AgNPs) to develop a novel, less invasive, and simple photothermal therapy technique for benign prostate hyperplasia (BPH).

MATERIALS AND METHODS

The shape, particle size, and zeta-potential of polyvinylpyrrolidone coated-AgNPs (PVP-AgNPs) were determined using transmission electron microscopy (TEM), Zeta-potential, and Particle size analyzer (ELSZ). To induce BPH, thirty-six male Sprague-Dawley (SD) rats were given intramuscular (i.m) injections of testosterone propionate (TP) at 5 mg/kg body weight (b.w)/day suspended in 0.1 ml of olive oil for 14 days. Photothermal therapy with AgNPs-NIR for 14 days was carried out. Prostate size, prostate index (PI), dihydrotestosterone (DHT), prostate-specific antigen (PSA), gross, hepatic, and renal toxicity, as well as antioxidant activity, apoptosis, and angiogenesis markers in prostatic tissues were measured. Histological examinations of prostates and biocompatibility of NIR-AgNPs on vital organs were also performed.

KEY FINDINGS

The aggregated spherical AgNPs with a mean size of 50-90 nm and a Zeta potential of -53.22 mV displayed high effectiveness in the NIR (532 nm-1 W) region by decreasing prostate size, PI, DHT, and PSA in BPH rats with no signs of gross, hepatic, or renal damage. As compared to alternative therapies, hyperthermia therapy increased antioxidant activities, induced apoptosis, inhibited angiogenesis, reduced histological alterations in the prostates of BPH rats, and improved biocompatibility of the vital organs.

SIGNIFICANCE

The current study demonstrated the effectiveness of plasmonic AgNPs photothermal therapy in the treatment of BPH.

Breast Cancer Cells Metastasize to the Tissue-Engineered Premetastatic Niche by Using an Osteoid-Formed Polycaprolactone/Nanohydroxyapatite Scaffold

It has been deemed that the premetastatic niche (PMN) plays a critical role in facilitating bone metastasis of breast cancer cells. Tissue engineering scaffolds provide an advantageous environment to promote osteogenesis that may mimic the bony premetastatic niches (BPMNs). In this study, human mesenchymal stem cells (hMSCs) were seeded onto designed polycaprolactone/nanohydroxyapatite (PCL-nHA) scaffolds for osteogenic differentiation. Subsequently, a coculture system was used to establish the tissue-engineered BPMNs by culturing breast cancer cells, hMSCs, and osteoid-formed PCL-nHA scaffolds. Afterwards, a migration assay was used to investigate the recruitment of MDA-MB-231, MCF-7, and MDA-MB-453 cells to the BPMNs' supernatants. The cancer stem cell (CSC) properties of these migrated cells were investigated by flow cytometry. Our results showed that the mRNA expression levels of alkaline phosphatase (ALP), Osterix, runt-related transcription factor 2 (Runx2), and collagen type I alpha 1 (COL1A1) on the PCL-nHA scaffolds were dramatically increased compared to the PCL scaffolds on days 11, 18, and 32. The expression of CXCL12 in these BPMNs was increased gradually over coculturing time, and it may be a feasible marker for BPMNs. Furthermore, migration analysis results showed that the higher maturation of BPMNs collectively contributed to the creation of a more favorable niched site for the cancerous invasion. The subpopulation of breast cancer stem cells (BCSCs) was more likely to migrate to fertile BPMNs. The proportion of BCSCs in metastatic MDA-MB-231, MCF-7, and MDA-MB-453 cells were increased by approximately 63.47%, 149.48%, and 127.60%. The current study demonstrated that a designed tissue engineering scaffold can provide a novel method to create a bone-mimicking environment that serves as a useable platform to recapitulate the BPMNs and help interrogate the scheme of bone metastasis by breast cancer.

Precision biomaterials in cancer theranostics and modelling

Despite significant achievements in the understanding and treatment of cancer, it remains a major burden. Traditional therapeutic approaches based on the 'one-size-fits-all' paradigm are becoming obsolete, as demonstrated by the increasing number of patients failing to respond to treatments. In contrast, more precise approaches based on individualized genetic profiling of tumors have already demonstrated their potential. However, even more personalized treatments display shortcomings mainly associated with systemic delivery, such as low local drug efficacy or specificity. A large amount of effort is currently being invested in developing precision medicine-based strategies for improving the efficiency of cancer theranostics and modelling, which are envisioned to be more accurate, standardized, localized, and less expensive. To this end, interdisciplinary research fields, such as biomedicine, material sciences, pharmacology, chemistry, tissue engineering, and nanotechnology, must converge for boosting the precision cancer ecosystem. In this regard, precision biomaterials have emerged as a promising strategy to detect, model, and treat cancer more efficiently. These are defined as those biomaterials precisely engineered with specific theranostic functions and bioactive components, with the possibility to be tailored to the cancer patient needs, thus having a vast potential in the increasing demand for more efficient treatments. In this review, we discuss the latest advances in the field of precision biomaterials in cancer research, which are expected to revolutionize disease management, focusing on their uses for cancer modelling, detection, and therapeutic applications. We finally comment on the needed requirements to accelerate their application in the clinic to improve cancer patient prognosis.

Tumor microenvironment remodeling-based penetration strategies to amplify nanodrug accessibility to tumor parenchyma

Remarkable advances in nano delivery systems have provided new hope for tumor prevention, diagnosis and treatment. However, only limited clinical therapeutic effects against solid tumors were achieved. One of the main reasons is the presence of abundant physiological and pathological barriers in vivo that impair tumoral penetration and distribution of the nanodrugs. These barriers are related to the components of tumor microenvironment (TME) including abnormal tumor vasculature, rich composition of the extracellular matrix (ECM), and abundant stroma cells. Herein, we review the advanced strategies of TME remodeling to overcome these biological obstacles against nanodrug delivery. This review aims to offer a perspective guideline for the implementation of promising approaches to facilitate intratumoral permeation of nanodrugs through alleviation of biological barriers. At the same time, we analyze the advantages and disadvantages of the corresponding methods and put forward possible directions for the future researches.

A Microfluidic Device for Automated High Throughput Detection of Ice Nucleation of Snomax®

Measurement of ice nucleation (IN) temperature of liquid solutions at sub-ambient temperatures has applications in atmospheric, water quality, food storage, protein crystallography and pharmaceutical sciences. Here we present details on the construction of a temperature-controlled microfluidic platform with multiple individually addressable temperature zones and on-chip temperature sensors for high-throughput IN studies in droplets. We developed, for the first time, automated droplet freezing detection methods in a microfluidic device, using a deep neural network (DNN) and a polarized optical method based on intensity thresholding to classify droplets without manual counting. This platform has potential applications in continuous monitoring of liquid samples consisting of aerosols to quantify their IN behavior, or in checking for contaminants in pure water. A case study of the two detection methods was performed using Snomax® (Snomax International, Englewood, CO, USA), an ideal ice nucleating particle (INP). Effects of aging and heat treatment of Snomax® were studied with Fourier transform infrared (FTIR) spectroscopy and a microfluidic platform to correlate secondary structure change of the IN protein in Snomax® to IN temperature. It was found that aging at room temperature had a mild impact on the ice nucleation ability but heat treatment at 95 °C had a more pronounced effect by reducing the ice nucleation onset temperature by more than 7 °C and flattening the overall frozen fraction curve. Results also demonstrated that our setup can generate droplets at a rate of about 1500/min and requires minimal human intervention for DNN classification.

Implantable and Injectable Biomaterial Scaffolds for Cancer Immunotherapy

Cancer immunotherapy has become an emerging strategy recently producing durable immune responses in patients with varieties of malignant tumors. However, the main limitation for the broad application of immunotherapies still to reduce side effects by controlling and regulating the immune system. In order to improve both efficacy and safety, biomaterials have been applied to immunotherapies for the specific modulation of immune cells and the immunosuppressive tumor microenvironment. Recently, researchers have constantly developed biomaterials with new structures, properties and functions. This review provides the most recent advances in the delivery strategies of immunotherapies based on localized biomaterials, focusing on the implantable and injectable biomaterial scaffolds. Finally, the challenges and prospects of applying implantable and injectable biomaterial scaffolds in the development of future cancer immunotherapies are discussed.

Genetically engineered magnetic nanocages for cancer magneto-catalytic theranostics

The clinical applications of magnetic hyperthermia therapy (MHT) have been largely hindered by the poor magnetic-to-thermal conversion efficiency of MHT agents. Herein, we develop a facile and efficient strategy for engineering encapsulin-produced magnetic iron oxide nanocomposites (eMIONs) via a green biomineralization procedure. We demonstrate that eMIONs have excellent magnetic saturation and remnant magnetization properties, featuring superior magnetic-to-thermal conversion efficiency with an ultrahigh specific absorption rate of 2390 W/g to overcome the critical issues of MHT. We also show that eMIONs act as a nanozyme and have enhanced catalase-like activity in the presence of an alternative magnetic field, leading to tumor angiogenesis inhibition with a corresponding sharp decrease in the expression of HIF-1α. The inherent excellent magnetic-heat capability, coupled with catalysis-triggered tumor suppression, allows eMIONs to provide an MRI-guided magneto-catalytic combination therapy, which may open up a new avenue for bench-to-bed translational research of MHT.

The clinical application of magnetic hyperthermia therapy (MHT) is limited by the poor magnetic-to-thermal conversion efficiency of MHT agents. Here, the authors develop encapsulin-produced magnetic iron oxide nanocomposites (eMIONs) with excellent magnetic-heat capability and catalysis-triggered tumor suppression ability to overcome the critical issues of MHT.

Recent advances in combinatorial cancer therapy via multifunctionalized gold nanoparticles

The diverse behavior of nanogold in the therapeutic field is related to its unique size and shape. Nanogold offers improvements in modern diagnostic and therapeutic implications, increases disease specificity and targeted drug delivery, and is relatively economical compared with other chemotherapeutic protocols. The diagnosis of cancer and photothermal therapy improve drastically with the implementation of nanotechnology. Different types of nanoparticles, that is, gold silica nanoshells, nanorods and nanospheres of diverse shapes and geometries, are used widely in the photothermal therapy of cancerous cells and nodules. Numerous reviews have been published on the therapeutic applications of gold nanoparticles, but studies on combinatorial applications of nanogold in cancer therapy are limited. This review focuses on the combinatorial cancer therapy using optical properties of nanogold with different shapes and geometries, and their therapeutic applications in cancer diagnosis, photothermal therapy, cancer imaging and targeted drug delivery.

Targeted drug delivery therapies inspired by natural taxes

A taxis is the movement responding to a stimulus of an organism. This behavior helps organisms to migrate, to find food or to avoid dangers. By mimicking and using natural taxes, many bio-inspired and bio-hybrid drug delivery systems have been synthesized. Under the guidance of physical and chemical stimuli, drug-loaded carriers are led to a target, for example tumors, then locally release the drug, inducing a therapeutic effect without influencing other parts of the body. On the other hand, for moving targets, for example metastasis cancer cells or bacteria, taking advantage of their taxes behavior is a solution to capture and to eliminate them. For instance, several traps and ecological niches have been fabricated to attract cancer cells by releasing chemokines. Cancer cells are then eliminated by drug loaded inside the trap, by radiotherapy focusing on the trap location or by simply removing the trap. Further research is needed to deeply understand the taxis behavior of organisms, which is essential to ameliorate the performance of taxes-inspired drug delivery application.

Optimizing Integrated Electrode Design for Irreversible Electroporation of Implanted Polymer Scaffolds

Irreversible electroporation (IRE) is an emerging technology for non-thermal ablation of solid tumors. This study sought to integrate electrodes into microporous poly(caprolactone) (PCL) scaffolds previously shown to recruit metastasizing cancer cells in vivo in order to facilitate application of IRE to disseminating cancer cells. As the ideal parallel plate geometry would render much of the porous scaffold surface inaccessible to infiltrating cells, numerical modeling was utilized to predict the spatial profile of electric field strength within the scaffold for alternative electrode designs. Metal mesh electrodes with 0.35 mm aperture and 0.16 mm wire diameter established electric fields with similar spatial uniformity as the parallel plate geometry. Composite PCL-IRE scaffolds were fabricated by placing cylindrical porous PCL scaffolds between two PCL dip-coated stainless steel wire meshes. PCL-IRE scaffolds exhibited no difference in cell infiltration in vivo compared to PCL scaffolds. In addition, upon application of IRE in vivo, cells infiltrating the PCL-IRE scaffolds were successfully ablated, as determined by histological analysis 3 days post-treatment. The ability to establish homogeneous electric fields within a biomaterial that can recruit metastatic cancer cells, especially when combined with immunotherapy, may further advance IRE technology beyond solid tumors to the treatment of systemic cancer.

Benign prostatic hyperplasia treatment using plasmonic nanoparticles irradiated by laser in a rat model

OBJECTIVE

In the current study we have stimulated the efficacy of plasmonic nanoparticles (NPs) by laser hyperthermia to achieve a less invasive method for tumor photothermal therapy of benign prostatic hyperplasia (BPH).

METHODS

The levels of apoptosis on induced BPH in rats were assessed after treatment and revealed and recorded by various assayed. Moreover, the expression of caspases was considered to demonstrate the apoptotic pathways due to laser induced plasmonic NPs.

RESULTS

In the Laser + NPs group prostate size of induced BPH decreased. Laser + NPs also decreased prostate specific antigen in comparison with the BPH groups. Furthermore, Laser + NPs attenuated BPH histopathologic indices in the rats. Laser + NPs induced apoptosis in prostatic epithelial cells via caspase-1 pathway.

CONCLUSIONS

Altogether, the approach and findings from this study can be applied to introduce the laser irritated NPs method as a novel and less invasive therapy for patients suffering from BPH.

Red-Emissive Carbon Quantum Dots for Nuclear Drug Delivery in Cancer Stem Cells

Large doses of anticancer drugs entering cancer cell nuclei are found to be effective at killing cancer cells and increasing chemotherapeutic effectiveness. Here we report red-emissive carbon quantum dots, which can enter into the nuclei of not only cancer cells but also cancer stem cells. After doxorubicin was loaded at the concentration of 30 μg/mL on the surfaces of carbon quantum dots, the average cell viability of HeLa cells was decreased to only 21%, while it was decreased to 50% for free doxorubicin. The doxorubicin-loaded carbon quantum dots also exhibited a good therapeutic effect by eliminating cancer stem cells. This work provides a potential strategy for developing carbon quantum-dot-based anticancer drug carriers for effective eradication of cancers.

Biphasic Injectable Bone Cement with Fe3O4/GO Nanocomposites for the Minimally Invasive Treatment of Tumor-Induced Bone Destruction

Minimally invasive surgery will be gradually applied to the surgical treatment of bone tumors. One of the difficulties in the minimally invasive treatment of bone tumors is the lack of injectable materials that can be used to treat tumor-induced bone defects. Therefore, it is imperative to develop an injectable bone filler that can not only be injected into the defect site by minimally invasive methods to provide strong support and repair bone tissue but also inactivate residual tumor cells around the defect. To achieve this aim, in our study, for the first time, we doped Fe₃O₄/graphene oxide (GO) nanocomposites into α-tricalcium phosphate (α-TCP)/calcium sulfate (CS) biphasic bone cement to prepare an injectable magnetic bone cement (α-TCP/CS/Fe₃O₄/GO, αCFG), which can be applied in bone tumor minimally invasive surgery and fit ideally even if the area is irregular. The magnetothermal performance of the αCFG bone cement could be well adjusted by altering the content of Fe₃O₄/GO nanocomposites and the magnetic field parameters, but a 10 wt % Fe₃O₄/GO content formed the most stable bone cement with excellent magnetothermal performance. The αCFG bone cement not only promotes bone regeneration but also exhibits enhanced tumor treatment effects. Such multifunctional bone cement could provide a promising clinical strategy for the minimally invasive treatment of tumor-induced bone destruction.

Reversing the Tumor Target: Establishment of a Tumor Trap

Despite the tremendous progress made in the field of cancer therapy in recent years, certain solid tumors still cannot be successfully treated. Alongside classical treatments in the form of chemotherapy and/or radiotherapy, targeted treatments such as immunotherapy that cause fewer side effects emerge as new options in the clinics. However, these alternative treatments may not be useful for treating all types of cancers, especially for killing infiltrative and circulating tumor cells (CTCs). Recent advances pursue the trapping of these cancer cells within a confined area to facilitate their removal for therapeutic and diagnostic purposes. A good understanding of the mechanisms behind tumor cell migration may drive the design of traps that mimic natural tumor niches and guide the movement of the cancer cells. To bring this trapping idea into reality, strong efforts are being made to create structured materials that imitate myelinated fibers, blood vessels, or pre-metastatic niches and incorporate chemical cues such as chemoattractants or adhesive proteins. In this review, the different strategies used (or could be used) to trap tumor cells are described, and relevant examples of their performance are analyzed.

Biomaterial Platform To Establish a Hypoxic Metastatic Niche in Vivo

Hypoxia is a hallmark of tumor microenvironments, exerting wide-ranging impacts on key processes of tumor progression and metastasis. However, our understanding of how hypoxia regulates these processes has been based primarily on studying the effects of hypoxia within the primary tumor. Recently, an increasing number of studies have suggested the importance of hypoxic regulation within metastatic target organs, but hypoxic metastatic niches in the body are difficult to access with current imaging techniques, hampering detailed in vivo investigation of hypoxia at metastatic sites. Here, we report an engineered biomaterial scaffold that is able to establish an in vivo hypoxic metastatic niche in a readily accessible area, enabling the investigation of hypoxic regulation at a metastatic site. We engineered hypoxic environments within microporous poly(lactide-co-glycolide) (PLG) scaffolds, which have previously been shown to act as premetastatic niche mimics, via the addition of CoCl2, a hypoxia-mimetic agent. When implanted into the subcutaneous region of mice, CoCl2-containing PLG (Co-PLG) scaffolds established hypoxic microenvironments, as evidenced by the stabilization of hypoxia-inducible factor 1α (HIF1α) and increased blood vessel formation in vitro and in vivo. Furthermore, implanted Co-PLG scaffolds were able to recruit 4T1 metastatic breast cancer cells. These results demonstrate that Co-PLG scaffolds can establish an in vivo hypoxic metastatic niche, providing a novel platform to investigate hypoxic regulation of disseminated tumor cells (DTCs) at target organs.