The rise and rise of stealth nanocarriers for cancer therapy: passive versus active targeting

PLGA nanocapsules as a delivery system for a recombinant LRP-based therapeutic

Telomerase activity is directly affected by the laminin receptor precursor (LRP) protein, a highly conserved nonintegrin transmembrane receptor, which has been shown to have therapeutic effects in ageing, and age-related diseases. Recently, it has been found that overexpression of LRP-FLAG, by plasmid transfection, leads to a significant increase in telomerase activity in cell culture models. This may indicate that upregulation of LRP can be used to treat various age-related diseases. However, transfection is not a viable treatment strategy for patients. Therefore, we present a nanoencapsulated protein-based drug synthesised using poly(lactic-co-glycolic acid) (PLGA) nanocapsules for delivery of the 37 kDa LRP protein therapeutic. PLGA nanocapsules were synthesised using the double emulsification-solvent evaporation technique. Different purification methods, including filtration and centrifugation, were tested to ensure that the nanocapsules were within the optimal size range, and the BCA assay was used to determine encapsulation efficiency. The completed drug was tested in a HEK-293 cell culture model, to investigate the effect on cell viability, LRP protein levels and telomerase activity. A significant increase in total LRP protein levels with a concomitant increase in cell viability and telomerase activity was observed. Due to the observed increase in telomerase activity, this approach could represent a safer alternative to plasmid transfection for the treatment of age-related diseases.

Stealth Nanocarriers in Cancer Therapy: a Comprehensive Review of Design, Functionality, and Clinical Applications

Nanotechnology has significantly transformed cancer treatment by introducing innovative methods for delivering drugs effectively. This literature review provided an in-depth analysis of the role of nanocarriers in cancer therapy, with a particular focus on the critical concept of the 'stealth effect.' The stealth effect refers to the ability of nanocarriers to evade the immune system and overcome physiological barriers. The review investigated the design and composition of various nanocarriers, such as liposomes, micelles, and inorganic nanoparticles, highlighting the importance of surface modifications and functionalization. The complex interaction between the immune system, opsonization, phagocytosis, and the protein corona was examined to understand the stealth effect. The review carefully evaluated strategies to enhance the stealth effect, including surface coating with polymers, biomimetic camouflage, and targeting ligands. The in vivo behavior of stealth nanocarriers and their impact on pharmacokinetics, biodistribution, and toxicity were also systematically examined. Additionally, the review presented clinical applications, case studies of approved nanocarrier-based cancer therapies, and emerging formulations in clinical trials. Future directions and obstacles in the field, such as advancements in nanocarrier engineering, personalized nanomedicine, regulatory considerations, and ethical implications, were discussed in detail. The review concluded by summarizing key findings and emphasizing the transformative potential of stealth nanocarriers in revolutionizing cancer therapy. This review enhanced the comprehension of nanocarrier-based cancer therapies and their potential impact by providing insights into advanced studies, clinical applications, and regulatory considerations.

Mitochondrial-Targeted Copper Delivery for Cuproptosis-Based Synergistic Cancer Therapy

Cuproptosis is dependent on mitochondrial respiration modulation by targeting lipoylated tricarboxylic acid cycle (TCA) cycle proteins, showing great potential in cancer treatment. However, the specific release of copper ions at mitochondrial is highly needed and still a major challenge to trigger cellular cuproptosis. Herein, a metal-organic framework-based nanoplatform (ZCProP) is designed for mitochondrial-targeted and ATP/pH-responsive Cu2+ and prodigiosin release. The released Cu2+ promotes aggregation of lipoylated protein and loss of Fe-S cluster protein, resulting in cell cuproptosis. In the meanwhile, Cu2+ can concert with prodigiosin to induce mitochondrial dysfunction and DNA damage and enhance cell cuproptosis. Furthermore, this nanoplatform has an ability to deplete glutathione, which not only further promotes cuproptosis but also triggers cell ferroptosis by the suppression of glutathione peroxidase 4, an anti-ferroptosis protein. Collectively, the designed ZCProP nanoplatform can responsively release cargos at mitochondrial and realize a conspicuous therapeutic efficacy through a cuproptosis-mediated concerted effect. Along with its excellent biocompatibility, this nanoplatform may provide a novel therapeutic modality paradigm to boost cancer therapeutic strategies based on cuproptosis.

Recent Progress and Challenges in Clinical Translation of Nanomedicines in Diagnosis and Treatment of Lung Cancer

Lung cancer is one of the leading causes of death across the world. There are numerous challenges in the early diagnosis and effective treatment of lung cancer, including developing multidrug resistance. However, the diagnosis of lung cancer could be minimally invasive or non-invasive. Nowadays, nanomedicines offer solutions to several emerging challenges in drug delivery research areas. It has the potential to enhance the therapeutic efficacy of biologically and chemically active agents at the site of action. This approach can also be employed in molecular and cellular imaging, precise and early detection, screening, and targeting drugs for lung cancer treatment. A proper understanding of the disease and timely diagnosis using strategically designed effective nanocarriers can be a promising approach to effectively managing cancer. The present review explores issues related to lung cancer chemotherapy and the promises and hurdles of newer approaches like nanomedicine. The article also summarizes the preclinical studies on diagnosis and treatment, pitfalls, and challenges in the clinical translation of nanomedicines for lung cancer therapy.

Thermal-triggered loading and GSH-responsive releasing property of HBc particles for drug delivery

Hepatitis B core protein virus-like particles (HBc VLPs) have attracted wide attentions using as drug delivery vehicles, due to its excellent stability and easy in large scale production. Here in the present work, we report unique thermal-triggered loading and glutathione-responsive releasing property of the HBc particles for anticancer drug delivery. Through reversible temperature-dependent hole gating of the HBc particle capsid, about 4248 doxorubicin (DOX) were successfully encapsulated inside nanocage of a single nanoparticle at high HBc recovery of 83.2%, by simply incubating the DOX with HBc at 70 °C for 90 min. The new strategy was significantly superior to the disassembly-reassembly methods, which can only yield 3556 DOX loading at 52.3% HBc recovery. The thermal-sensitive drug entry channel in HBc was analyzed by molecular dynamic simulations, and the G113, G117 and R127 were identified as the key amino acid residues that are not conducive to the entrance of DOX but sensitive to temperature. Especially, the ΔGbind of R127 become even higher at high temperature, mutation of the R127 would be the first choice to make the drug entry thermodynamically easier. Due to plenty of disulfide bonds linking the HBc subunits, the HBc particles loaded with DOX exhibited intrinsic glutathione (GSH) responsivity for efficient controlled release in tumor sites. To further increase the tumor-targeting effect of the drug, Cyclo(Arg-Gly-Asp-d-Tyr-Lys) peptide was conjugated to the surface of HBc through a PEG linker. The prepared HBc-based anticancer drug showed significantly improved stability, tumor specificity, and in vivo anticancer activity on MCF7-bearing Balb/c-nu mice. Overall, our work demonstrated that the HBc VLPs can be an ideal drug carrier to fulfill requirement of the intelligent loading and "on demand" release of the therapeutic agents for efficient cancer therapy with minimal adverse effects.

Advances in Lung Cancer Treatment Using Nanomedicines

Carcinoma of the lungs is among the most menacing forms of malignancy and has a poor prognosis, with a low overall survival rate due to delayed detection and ineffectiveness of conventional therapy. Therefore, drug delivery strategies that may overcome undesired damage to healthy cells, boost therapeutic efficacy, and act as imaging tools are currently gaining much attention. Advances in material science have resulted in unique nanoscale-based theranostic agents, which provide renewed hope for patients suffering from lung cancer. Nanotechnology has vastly modified and upgraded the existing techniques, focusing primarily on increasing bioavailability and stability of anti-cancer drugs. Nanocarrier-based imaging systems as theranostic tools in the treatment of lung carcinoma have proven to possess considerable benefits, such as early detection and targeted therapeutic delivery for effectively treating lung cancer. Several variants of nano-drug delivery agents have been successfully studied for therapeutic applications, such as liposomes, dendrimers, polymeric nanoparticles, nanoemulsions, carbon nanotubes, gold nanoparticles, magnetic nanoparticles, solid lipid nanoparticles, hydrogels, and micelles. In this Review, we present a comprehensive outline on the various types of overexpressed receptors in lung cancer, as well as the various targeting approaches of nanoparticles.

Promising Therapeutic Strategies for Colorectal Cancer Treatment Based on Nanomaterials

Colorectal cancer (CRC) is a global health problem responsible for 10% of all cancer incidences and 9.4% of all cancer deaths worldwide. The number of new cases increases per annum, whereas the lack of effective therapies highlights the need for novel therapeutic approaches. Conventional treatment methods, such as surgery, chemotherapy and radiotherapy, are widely applied in oncology practice. Their therapeutic success is little, and therefore, the search for novel technologies is ongoing. Many efforts have focused recently on the development of safe and efficient cancer nanomedicines. Nanoparticles are among them. They are uniquewith their properties on a nanoscale and hold the potential to exploit intrinsic metabolic differences between cancer and healthy cells. This feature allows them to induce high levels of toxicity in cancer cells with little damage to the surrounding healthy tissues. Graphene oxide is a promising 2D material found to play an important role in cancer treatments through several strategies: direct killing and chemosensitization, drug and gene delivery, and phototherapy. Several new treatment approaches based on nanoparticles, particularly graphene oxide, are currently under research in clinical trials, and some have already been approved. Here, we provide an update on the recent advances in nanomaterials-based CRC-targeted therapy, with special attention to graphene oxide nanomaterials. We summarise the epidemiology, carcinogenesis, stages of the CRCs, and current nanomaterials-based therapeutic approaches for its treatment.

Impact of RAFT chain transfer agents on the polymeric shell density of magneto-fluorescent nanoparticles and their cellular uptake

The impact of nanoparticle surface chemistry on cell interactions and especially cell uptake has become evident over the last few years in nanomedicine. Since PEG polymers have proved to be ideal tools for attaining stealthiness and favor escape from the in vivo mononuclear phagocytotic system, the accurate control of their geometry is of primary importance and can be achieved through reversible addition-fragmentation transfer (RAFT) polymerization. In this study, we demonstrate that the residual groups of the chain transfer agents (CTAs) introduced in the main chain exert a significant impact on the cellular internalization of functionalized nanoparticles. High-resolution magic angle spinning ¹H NMR spectroscopy and fluorescence spectroscopy permitted by the magneto-fluorescence properties of nanoassemblies (NAs) revealed the compaction of the PEG comb-like shell incorporating CTAs with a long alkyl chain, without changing the overall surface potential. As a consequence of the capability of alkyl units to self-assemble at the NA surface while hardly contributing more than 0.5% to the total polyelectrolyte weight, denser PEGylated NAs showed notably less internalization in all cells of the tumor microenvironment (tumor cells, macrophages and healthy cells). Interestingly, such differentiated uptake is also observed between pro-inflammatory M1-like and immunosuppressive M2-like macrophages, with the latter more efficiently phagocytizing NAs coated with a less compact PEGylated shell. In contrast, the NA diffusion inside multicellular spheroids, used to mimic solid tumors, appeared to be independent of the NA coating. These results provide a novel effort-saving approach where the sole variation of the chemical nature of CTAs in RAFT PEGylated polymers strikingly modulate the cell uptake of nanoparticles upon the organization of their surface coating and open the pathway toward selectively addressing macrophage populations for cancer immunotherapy.

Nanoparticle-based strategies to target HIV-infected cells

Antiretroviral drugs employed for the treatment of human immunodeficiency virus (HIV) infections have remained largely ineffective due to their poor bioavailability, numerous adverse effects, modest uptake in infected cells, undesirable drug-drug interactions, the necessity for long-term drug therapy, and lack of access to tissues and reservoirs. Nanotechnology-based interventions could serve to overcome several of these disadvantages and thereby improve the therapeutic efficacy of antiretrovirals while reducing the morbidity and mortality due to the disease. However, attempts to use nanocarriers for the delivery of anti-retroviral drugs have started gaining momentum only in the past decade. This review explores in-depth the various nanocarriers that have been employed for the treatment of HIV infections highlighting their merits and possible demerits.

RNAi-based therapeutics and tumor targeted delivery in cancer

Over the past decade, non-coding RNA-based therapeutics have proven as a great potential for the development of targeted therapies for cancer and other diseases. The discovery of the critical function of microRNAs (miRNAs) has generated great excitement in developing miRNA-based therapies. The dysregulation of miRNAs contributes to the pathogenesis of various human diseases and cancers by modulating genes that are involved in critical cellular processes, including cell proliferation, differentiation, apoptosis, angiogenesis, metastasis, drug resistance, and tumorigenesis. miRNA (miRNA mimic, anti-miRNA/antagomir) and small interfering RNA (siRNA) can inhibit the expression of any cancer-related genes/mRNAs with high specificity through RNA interference (RNAi), thus representing a remarkable therapeutic tool for targeted therapies and precision medicine. siRNA and miRNA-based therapies have entered clinical trials and recently three novel siRNA-based therapeutics were approved by the Food and Drug Administration (FDA), indicating the beginning of a new era of targeted therapeutics. The successful clinical applications of miRNA and siRNA therapeutics rely on safe and effective nanodelivery strategies for targeting tumor cells or tumor microenvironment. For this purpose, promising nanodelivery/nanoparticle-based approaches have been developed using a variety of molecules for systemic administration and improved tumor targeted delivery with reduced side effects. In this review, we present an overview of RNAi-based therapeutics, the major pharmaceutical challenges, and the perspectives for the development of promising delivery systems for clinical translation. We also highlight the passive and active tumor targeting nanodelivery strategies and primarily focus on the current applications of nanoparticle-based delivery formulations for tumor targeted RNAi molecules and their recent advances in clinical trials in human cancers.

Mixed-charge modification as a robust method to realize the antiviral ability of gold nanoparticles in a high protein environment

Pandemics caused by viruses have resulted in incalculable losses to human beings, which are exacerbated due to the lack of antiviral drugs. Sulfonic group modified nanomedicine has been proved to possess a broad-spectrum antiviral ability. However, it is very challenging to maintain the antiviral activity in a high protein environment in vivo. To improve the tolerance to the complex biological environment, sulfonic mixed-charge modified gold nanoparticles (MC_AuNPs) were prepared in this research by introducing positively charged ligands into sulfonic ligand modified gold nanoparticles. The MC_AuNPs showed excellent non-fouling ability while retaining comparable antiviral ability to single sulfonic ligand modified gold nanoparticles (MDS_AuNPs). The MC_AuNPs maintained their antiviral ability in 10 mg mL^-1 protein solutions, but the MDS_AuNPs completely lost their antiviral capability in 1 mg mL^-1 protein medium. The mixed-charge modification strategy provides a practical avenue to maintain the antiviral capability of HSPG mimicking nanoparticles in high protein environments.

Optimizing Comprehensive Performance of Aggregation-Induced Emission Nanoparticles through Molecular Packing Modulation for Multimodal Image-Guided Synergistic Phototherapy

Fluorescent nanoparticles (NPs) with aggregation-induced emission (AIE) characteristics hold remarkable potential for image-guided phototherapy. The molecular packing is the key point for optimizing the performance of AIE luminogens (AIEgens) in the aggregated or solid state. However, so far, the packing mode of AIEgens in NPs is still vague, causing some challenges for understanding the relationship between the photophysical property and packing mode, as well as further optimizing the performance of NPs for biomedical applications. In this contribution, by simply controlling the length of alkoxy chains in the donor-acceptor conjugated OPTPA, a packing balance between the twisted molecular structure and effective π-conjugation is actualized. Subsequently, the possibility of amorphous-crystalline transition of AIEgens in the polymer-encapsulated NPs is presented for the first time, and the comprehensive performance of NPs is further optimized. Both in vitro and in vivo experiments indicate that crystalline AIEgen-based NPs are remarkably effective in trimodal imaging-guided synergistic phototherapy.

Photothermal and Enhanced Photocatalytic Therapies Conduce to Synergistic Anticancer Phototherapy with Biodegradable Titanium Diselenide Nanosheets

Nanomaterial-based photothermal and photocatalytic therapies are effective against various types of cancers. However, combining two or more materials is considered necessary to achieve the synergistic anticancer effects of photothermal and photocatalytic therapy, which made the preparation process complicated. Herein, the authors describe simple 2D titanium diselenide (TiSe₂ ) nanosheets (NSs) that can couple photothermal therapy with photocatalytic therapy. The TiSe₂ NSs are prepared using a liquid exfoliation method. They show a layered structure and possess high photothermal conversion efficiency (65.58%) and good biocompatibility. Notably, upon near-infrared irradiation, these NSs exhibit good photocatalytic properties with enhanced reactive oxygen species generation and H₂ O₂ decomposition in vitro. They can also achieve high temperatures, with heat improving their catalytic ability to further amplify oxidative stress and glutathione depletion in cancer cells. Furthermore, molecular mechanism studies reveal that the synergistic effects of photothermal and enhanced photocatalytic therapy can simultaneously lead to apoptosis and necrosis in cancer cells via the HSP90/JAK3/NF-κB/IKB-α/Caspase-3 pathway. Systemic exploration reveals that the TiSe₂ NSs has an appreciable degradation rate and accumulates passively in tumor tissue, where they facilitate photothermal and photocatalytic effects without obvious toxicity. Their study thus indicates the high potential of biodegradable TiSe₂ NSs in synergistic phototherapy for cancer treatment.

One-for-All Phototheranostic Agent Based on Aggregation-Induced Emission Characteristics for Multimodal Imaging-Guided Synergistic Photodynamic/Photothermal Cancer Therapy

Phototheranostics represents a promising direction for modern precision medicine, which has recently received considerable attention for cancer research. The ingenious integration of all phototheranostic modalities in a single molecule with precise spatial colocalization is a tremendously challenging task, which mainly arises from the complexity of molecular design and energy dissipation. Reports on a single molecular one-for-all theranostic agent are still very rare. Herein, we designed two novel aggregation-induced emission (AIE)-active fluorogens (AIEgens, named DPMD and TPMD) with a cross-shaped donor-acceptor structure via a facile synthetic method and constructed versatile nanoparticles (NPs) by encapsulating AIEgen with an amphiphilic polymer. The AIEgen TPMD with a twisted structure, high donor-acceptor (D-A) strength, small singlet-triplet energy gap, and abundant intramolecular rotators and vibrators was selected as an ideal candidate for balancing and utilizing the radiative and nonradiative energy dissipations. Notably, TPMD NPs simultaneously possess adequate near-infrared (NIR) fluorescence emission at 821 nm for fluorescence imaging, effective reactive oxygen species generation for photodynamic therapy (PDT), and outstanding photothermal effect for photoacoustic imaging, photothermal imaging, and photothermal therapy (PTT), which demonstrates the superior potential of AIE NPs in multimodal imaging-guided synergistic PDT/PTT therapy.

Metallic nanoparticles as drug delivery system for the treatment of cancer

INTRODUCTION

The targeted delivery of anticancer agents to tumor is a major challenge because most of the drugs show off-target effect resulting in nonspecific cell death. Multifunctionalized metallic nanoparticles (NPs) are explored as new carrier system in the era of cancer therapeutics. Researchers investigated the potential of metallic NPs to target tumor cells by active and passive mechanisms, thereby reducing off-target effects of anticancer agents. Moreover, photocatalytic activity of upconversion nanoparticles (UCNPs) and the enhanced permeation and retention (EPR) effect have also gained wide potential in cancer treatment. Recent advancement in the field of nanotechnology highlights their potency for cancer therapy.

AREAS COVERED

This review summarizes the types of gold and silver metallic NPs with targeting mechanisms and their potentiality in cancer therapy.

EXPERT OPINION

Recent advances in the field of nanotechnology for cancer therapy offer high specificity and targeting efficiency. Targeting tumor cells through mechanistic pathways using metallic NPs for the disruption/alteration of molecular profile and survival rate of the tumor cells has led to an effective approach for cancer therapeutics. This alteration in the survival rate of the tumor cells might decrease the proliferation thereby resulting in more efficient management in the treatment of cancer.

Engineering the drug carrier biointerface to overcome biological barriers to drug delivery

Micro and nanoscale drug carriers must navigate through a plethora of dynamic biological systems prior to reaching their tissue or disease targets. The biological obstacles to drug delivery come in many forms and include tissue barriers, mucus and bacterial biofilm hydrogels, the immune system, and cellular uptake and intracellular trafficking. The biointerface of drug carriers influences how these carriers navigate and overcome biological barriers for successful drug delivery. In this review, we examine how key material design parameters lead to dynamic biointerfaces and improved drug delivery across biological barriers. We provide a brief overview of approaches used to engineer key physicochemical properties of drug carriers, such as morphology, surface chemistry, and topography, as well as the development of dynamic responsive materials for barrier navigation. We then discuss essential biological barriers and how biointerface engineering can enable drug carriers to better navigate and overcome these barriers to drug delivery.

Redox responsive nanoparticle encapsulating black phosphorus quantum dots for cancer theranostics

Effective cancer treatment puts high demands for cancer theranostics. For cancer diagnostics, optical coherence tomography (OCT) technology (including photothermal optical coherence tomography (PT-OCT)) has been widely investigated since it induces changes in optical phase transitions in tissue through environmental changes (such as temperature change for PT-OCT). In this report, redox responsive nanoparticle encapsulating black phosphorus quantum dots was developed as a robust PT-OCT agent. Briefly, black phosphorus quantum dots (BPQDs) are incorporated into cysteine-based poly-(disulfide amide) (Cys-PDSA) to form stable and biodegradable nanoagent. The excellent photothermal feature allows BPQD/Cys-PDSA nanoparticles (NPs) as a novel contrast agent for high-resolution PT-OCT bioimaging. The Cys-PDSA can rapidly respond to glutathione and effectively release BPQDs and drugs in vitro and in vivo. And the obtained NPs exhibit excellent near-infrared (NIR) photothermal transduction efficiency and drug delivery capacity that can serve as novel therapeutic platform, with very low chemo drug dosage and side effects. Both of the polymer and BPQD are degradable, indicating this platform is a rare PT-OCT agent that is completely biodegradable. Overall, our research highlights a biodegradable and biocompatible black phosphorus-based nanoagent for both cancer diagnosis and therapy.

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Black phosphorus based nanoplatform, the first PT-OCT nanoplatform could be completely degraded in vitro and in vivo.

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Black phosphorus quantum dots and chemo drugs have been successfully encapsulated into redox responsive nanoparticles.

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Very low dose of PTX (such as 1 mg/kg, 1/10 of normal dose) could achieve excellent therapeutic performance for this platform.

Controlled anti-cancer drug release through advanced nano-drug delivery systems: Static and dynamic targeting strategies

Advances in nanomedicine, including early cancer detection, targeted drug delivery, and personalized approaches to cancer treatment are on the rise. For example, targeted drug delivery systems can improve intracellular delivery because of their multifunctionality. Novel endogenous-based and exogenous-based stimulus-responsive drug delivery systems have been proposed to prevent the cancer progression with proper drug delivery. To control effective dose loading and sustained release, targeted permeability and individual variability can now be described in more-complex ways, such as by combining internal and external stimuli. Despite these advances in release control, certain challenges remain and are identified in this research, which emphasizes the control of drug release and applications of nanoparticle-based drug delivery systems. Using a multiscale and multidisciplinary approach, this study investigates and analyzes drug delivery and release strategies in the nanoparticle-based treatment of cancer, both mathematically and clinically.

Natural Hydrogels Applied in Photodynamic Therapy

Natural hydrogels are three-dimensional (3D) water-retaining materials with a skeleton consisting of natural polymers, their derivatives or mixtures. Natural hydrogels can provide sustained or controlled drug release and possess some unique properties of natural polymers, such as biodegradability, biocompatibility and some additional functions, such as CD44 targeting of hyaluronic acid. Natural hydrogels can be used with photosensitizers (PSs) in photodynamic therapy (PDT) to increase the range of applications. In the current review, the pertinent design variables are discussed along with a description of the categories of natural hydrogels available for PDT.

Two-dimensional silicene composite nanosheets enable exogenous/endogenous-responsive and synergistic hyperthermia-augmented catalytic tumor theranostics

Silicene as an emerging two-dimensional material (2DM) spurs the broad research interests due to its prominent electronic and physical properties, however, still lacking in exploitation for the biological and medical practices. Herein, we constructed a 2D silicene-based theranostic nanoplatform, MnO_x@silicene-BSA (MS-BSA), with tumor microenvironment (TME)-responsive and synergistic hyperthermia-augmented catalytic activity when irradiated by near infrared-II (NIR-II) laser because of the high photothermal-conversion efficiency of 2D silicene matrix. Such MS-BSA nanosheets possess the capability to react with glutathione (GSH) to generate Mn²⁺ and glutathione disulfide (GSSG) under acidity/reducing TME condition. With the presence/assistance of HCO₃^-, the released Mn²⁺ exhibited sensitive catalytic activity towards endogenous H₂O₂via Fenton-like reaction, enabling the generation of highly toxic hydroxyl radicals (•OH), which finally led to the enhanced nanocatalytic therapeutic efficacy followed by exogenous NIR-II laser exposure, originating from hyperthermia-augmented catalytic activity. Especially, these MS-BSA nanosheets accumulated into the tumor region to enable superb contrast enhancement of TME-responsive T₁-weighted magnetic resonance imaging (MRI) and photoacoustic imaging (PAI), and high-efficient in vivo synergistic tumor eradication. Therefore, such an intelligent photothermal-enhanced catalytic theranostic nanoplatform could realize the exogenous/endogenous-responsive and cooperative hyperthermia-augmented tumor treatment and accurate tumor positioning/monitoring.

The Effect of Ligand Mobility on the Cellular Interaction of Multivalent Nanoparticles

Multivalent nanoparticle binding to cells can be of picomolar avidity making such interactions almost as intense as those seen with antibodies. However, reducing nanoparticle design exclusively to avidity optimization by the choice of ligand and its surface density does not sufficiently account for controlling and understanding cell-particle interactions. Cell uptake, for example, is of paramount significance for a plethora of biomedical applications and does not exclusively depend on the intensity of multivalency. In this study, it is shown that the mobility of ligands tethered to particle surfaces has a substantial impact on particle fate upon binding. Nanoparticles carrying angiotensin-II tethered to highly mobile 5 kDa long poly(ethylene glycol) (PEG) chains separated by ligand-free 2 kDa short PEG chains show a superior accumulation in angiotensin-II receptor type 1 positive cells. In contrast, when ligand mobility is constrained by densely packing the nanoparticle surface with 5 kDa PEG chains only, cell uptake decreases by 50%. Remarkably, irrespective of ligand mobility and density both particle types have similar EC50 values in the 1-3 × 10^-9 m range. These findings demonstrate that ligand mobility on the nanoparticle corona is an indispensable attribute to be considered in particle design to achieve optimal cell uptake via multivalent interactions.

Synthetic copolymer conjugates of docetaxel and in vitro assessment of anticancer efficacy

Docetaxel (DTX) is a widely used chemotherapy drug that is associated with numerous side effects and limited bioavailability. We show synthetic copolymer conjugates of docetaxel with drug loading up to 20% and assess their efficacy in MCF-7 cells.

EphA2-Receptor Targeted PEGylated Nanoliposomes for the Treatment of BRAFV600E Mutated Parent- and Vemurafenib-Resistant Melanoma

The clinical outcomes of malignant melanoma have improved with the introduction of mitogen-activated protein kinase kinase (MEK) inhibitors. However, off-target toxicities of the MEK inhibitor trametinib (TMB) often result in dose interruption and discontinuation of therapy. The purpose of this study was to anchor a physically stable EphrinA1-mimicking peptide known as YSA (YSAYPDSVPMMS) on TMB-loaded PEGylated nanoliposomes (YTPLs), and evaluate them in BRAF^V600E-mutated parent cells (lines A375 and SK-MEL-28) and vemurafenib-resistant cells lines (A375R and SK-MEL-28R) in melanoma. TMB-loaded PEGylated liposomes (TPL) functionalized with nickel-chelated phospholipids were prepared using a modified hydration method. The hydrodynamic diameter and zeta potential values of optimized YTPL were 91.20 ± 12.16 nm and –0.92 ± 3.27 mV, respectively. The drug release study showed TPL did not leak or burst release in 24 h. The hemolysis observed was negligible at therapeutic concentrations of TMB. A differential scanning calorimetry (DSC) study confirmed that TMB was retained in a solubilized state within lipid bilayers. YTPL showed higher intracellular uptake in parental cell lines compared to vemurafenib-resistant cell lines. Western blot analysis and a cytotoxicity study with the EphA2 inhibitor confirmed a reduction in EphA2 expression in resistant cell lines. Thus, EphA2 receptor-targeted nanoliposomes can be useful for metastatic melanoma-specific delivery of TMB.

Sorafenib encapsulated in nanocarrier functionalized with glypican-3 specific peptide for targeted therapy of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the fifth most common cancer in the world with increasing incidence. Chemotherapy is required for HCC patients after receiving surgical resection. Serious off-target induced side effects and systemic toxicity limit the clinical utility of drugs. Targeting therapeutic nanomedicine is an innovative strategy for enhancing drug delivery efficiency and reducing side effects. Here, we successfully formulated nanocarriers to encapsulate sorafenib, an FDA approved drug for treatment of HCC. Sorafenib is encapsulated with an entrapment efficiency >80% over 20 days. The effective aqueous solubility is improved over 1900-fold. The release ratio in vitro is characterized by a half-life of T_1/2 = 22.7 h. The peak target-to-background ratio for nanocarrier uptake by tumor occurs at 24 h post-injection, and is significantly greater for the target peptide versus controls. Ex vivo biodistribution confirms the in vivo results. Tumor regression is significantly greater for the target peptide versus controls after 21 days of therapy. No acute toxicity is found by blood chemistry or necropsy. In summary, a peptide specific for GPC3 has been identified, and used to modify the surface of a nanocarrier that encapsulates sorafenib with high entrapment efficiency. Regression of HCC xenograft tumors showed promise for targeted drug delivery.

Recent advances in the targeting of systemically administered non-viral gene delivery systems

Introduction: Systemically administered non-viral gene delivery systems face multiple biological barriers that decrease their efficiency. These systems are rapidly cleared from the circulation and sufficient concentrations do not accumulate in diseased tissues. A number of targeting strategies can be used to provide for sufficient accumulation in the desired tissues to achieve a therapeutic effect. Areas covered: We discuss recent advances in the targeting of non-viral gene delivery systems to different tissues after systemic administration. We compare passive and active targeting applied for tumor delivery and propose some strategies that can be used to overcome the drawbacks of each case. We also discuss targeting the liver and lungs as two particularly important organs in gene therapy. Expert opinion: There is currently no optimum non-viral gene delivery system for targeting genes to specific tissues. The dose delivered to tumor tissues using passive targeting is low and shows a high patient variation. Although active targeting can enhance binding to specific cells, only a few reports are available to support its value in vivo. The design of smart nanocarriers for promoting active targeting is urgently needed and targeting the endothelium is a promising strategy for gene delivery to tumors as well as other organs.

A robust systematic design: Optimization and preparation of polymeric nanoparticles of PLGA for docetaxel intravenous delivery

Poly (lactide-co-glycolide) (PLGA) is a biocompatible, biodegradable, and non-toxic polymer used in a variety of biomedical and pharmaceutical applications. Polymeric nanoparticles prepared from PLGA have been extensively used as delivery vehicles of various chemotherapeutic agents. The variability of PLGA polymer and nanoparticle fabrication process potentially results in variability of particle characteristics. Nanoparticle characteristics determine nanoparticles' performance when used as drug delivery systems. Having control on nanoparticle's characteristics grants control over the fate of nanoparticles and the associated drug. Here, L16 Taguchi experimental design was used to evaluate the effect of polymer characteristics and fabrication variables on PLGA nanoparticles. The design was used to determine an optimized preparation condition for PLGA nanoparticles as an intravenous delivery system for docetaxel. An emulsification-solvent-evaporation method was used to fabricate nanoparticles. Docetaxel concentration, organic phase:aqueous phase ratio, polymer molecular weight, polymer terminus, lactide:glycolide ratio, and Poly(vinyl alcohol)(PVA) concentration were selected as main determinants. First two factors were evaluated at 4 levels and the rest at 2 levels. Particle-important characteristics including size, polydispersity index (PDI), surface charge (zeta potential), and docetaxel loading-efficiency were determined. Factors affecting nanoparticle characteristics were ranked according to level of effectiveness. Factors that affected nanoparticle properties with statistical significance were identified. Models to predict nanoparticle characteristics were built. An optimized fabrication method was identified and used to prepare PLGA nanoparticles for docetaxel delivery.

Particle toxicology and health - where are we?

Background

Particles and fibres affect human health as a function of their properties such as chemical composition, size and shape but also depending on complex interactions in an organism that occur at various levels between particle uptake and target organ responses.

While particulate pollution is one of the leading contributors to the global burden of disease, particles are also increasingly used for medical purposes. Over the past decades we have gained considerable experience in how particle properties and particle-bio interactions are linked to human health. This insight is useful for improved risk management in the case of unwanted health effects but also for developing novel medical therapies. The concepts that help us better understand particles’ and fibres’ risks include the fate of particles in the body; exposure, dosimetry and dose-metrics and the 5 Bs: bioavailability, biopersistence, bioprocessing, biomodification and bioclearance of (nano)particles. This includes the role of the biomolecule corona, immunity and systemic responses, non-specific effects in the lungs and other body parts, particle effects and the developing body, and the link from the natural environment to human health. The importance of these different concepts for the human health risk depends not only on the properties of the particles and fibres, but is also strongly influenced by production, use and disposal scenarios.

Conclusions

Lessons learned from the past can prove helpful for the future of the field, notably for understanding novel particles and fibres and for defining appropriate risk management and governance approaches.

Sulforaphane-conjugated selenium nanoparticles: towards a synergistic anticancer effect

Sulforaphane-modified selenium nanoparticles can be prepared in a simple aqueous-phase redox reaction through reduction of selenite with ascorbic acid. The sulforaphane molecules present in the reaction mixture adsorb on the nanoparticle surface, forming an adlayer. The resulting conjugate was examined with several physicochemical techniques, including microscopy, spectroscopy, x-ray diffraction, dynamic light scattering and zeta potential measurements. As shown in in vivo investigations on rats, the nanomaterial administered intraperitoneally is eliminated mainly in urine (and, to a lesser extent, in feces); however, it is also retained in the body. The modified nanoparticles mainly accumulate in the liver, but the basic parameters of blood and urine remain within normal limits. The sulforaphane-conjugated nanoparticles reveal considerable anticancer action, as demonstrated on several cancer cell cultures in vitro. This finding is due to the synergistic effect of elemental selenium and sulforaphane molecules assembled in one nanostructure (conjugate). On the other hand, the cytotoxic action on normal cells is relatively low. The high antitumor activity and selectivity of the conjugate with respect to diseased and healthy cells is extremely promising from the point of view of cancer treatment.

Model Affitin and PEG modifications onto siRNA lipid nanocapsules: cell uptake and in vivo biodistribution improvements

Malignant melanoma is an aggressive tumor, associated with the presence of local and/or distant metastases. The development of gene therapy by the use of small interfering RNA (siRNA) represents a promising new treatment. However, the protection of this biomolecule is necessary in order for it to be intravenously administrated, for example via its incorporation into nanomedicines. In parallel to the passive targeting usually obtained by pegylation, various studies have aimed at developing “smart” nanomedicines to efficiently deliver the drug to tumor sites. In this work, siRNA loaded lipid nanocapsules (LNCs) were modified with DSPE-polyethylene glycol (DSPE-PEG), tetraether-PEG (TE-PEG) and/or with an Affitin model, to assay multiple targeting strategies. The uptake of fluorescently labelled LNCs, nanocarrier integrity and siRNA release into human SK-Mel28 melanoma cells were studied by flow cytometry, conventional confocal microscopy and by confocal spectral imaging in a Förster Resonance Energy Transfer (FRET) mode. Surface modified siRNA LNCs were followed after human plasma incubation and after intravenous injection, in order to compare the stealth properties. Finally, the biodistribution of the different siRNA LNCs in healthy and melanoma tumor bearing mice models was assessed by in vivo biofluorescence imaging (BFI), to evaluate the potential tumor targeting ability. The post-insertion of DSPE-PEG induced a strong decrease of the internalization into melanoma cells compared to TE-PEG modification. Both PEG polymer decorations induced a great plasma protection of siRNA but only DSPE-PEG led to stealth properties, even at low concentration (5 mM). The Affitin grafting by thiolation of DSPE-PEG was validated on siRNA LNCs. DSPE-PEG-Affitin LNCs were not detected in this melanoma tumor model but did not show unspecific accumulation in organs. DSPE-PEG and TE-PEG LNCs induced a significant intratumoral accumulation of modified LNCs.

Surface modifications of siRNA LNCs were assessed with innovative TE-PEG polymers and an Affitin model, in comparison to classic DSPE-PEG LNCs, in order to evaluate the potential tumor targeting of siRNA after intravenous administration.

Sterically Stabilized RIPL Peptide-Conjugated Nanostructured Lipid Carriers: Characterization, Cellular Uptake, Cytotoxicity, and Biodistribution

As a platform for hepsin-specific drug delivery, we previously prepared IPLVVPLRRRRRRRRC peptide (RIPL)-conjugated nanostructured lipid carriers (RIPL-NLCs) composed of Labrafil® M 1944 CS (liquid oil) and Precirol® ATO 5 (solid lipid). In this study, to prevent the recognition by the mononuclear phagocyte system, polyethylene glycol (PEG)-modified RIPL-NLCs (PEG-RIPL-NLCs) were prepared using PEG3000 at different grafting ratios (1, 5, and 10 mole %). All prepared NLCs showed a homogeneous dispersion (130⁻280 nm), with zeta potentials varying from -18 to 10 mV. Docetaxel (DTX) was successfully encapsulated in NLCs: encapsulation efficiency (93⁻95%); drug-loading capacity (102⁻109 µg/mg). PEG-RIPL-NLCs with a grafting ratio of 5% PEG or higher showed significantly reduced protein adsorption and macrophage phagocytosis. The uptake of PEG(5%)-RIPL-NLCs by cancer cell lines was somewhat lower than that of RIPL-NLCs because of the PEG-induced steric hindrance; however, the uptake level of PEG-RIPL-NLCs was still greater than that of plain NLCs. In vivo biodistribution was evaluated after tail vein injection of NLCs to normal mice. Compared to RIPL-NLCs, PEG(5%)-RIPL-NLCs showed lower accumulation in the liver, spleen, and lung. In conclusion, we found that PEG(5%)-RIPL-NLCs could be a promising nanocarrier for selective drug targeting with a high payload of poorly water-soluble drugs.

Noninvasive photothermal cancer therapy nanoplatforms via integrating nanomaterials and functional polymers

In the cutting-edge field of cancer therapy, noninvasive photothermal therapy (PTT) has received great attention because it is considered to overcome the drawbacks of conventional surgery, radiotherapy and chemotherapy of severe body injuries and side effects on the immune system. The construction of PTT therapeutic and theranostic nanoplatforms is the key issue in achieving tumor targeting, imaging and therapy in a synergetic manner. In this review, we focus on the recent advances in constructing PTT therapeutic and theranostic nanoplatforms by integrating nanomaterials and functional polymers. The noninvasive photothermal cancer therapy mechanism and achievement strategies of PTT therapeutic and theranostic nanoplatforms are presented as well as the innovative construction strategies and perspectives for the future. Owing to their high tumor ablation efficiency, biological availability and low- or non-toxicity, PTT therapeutic and theranostic nanoplatforms are promising and emerging in medicine and clinical applications.

Reassessment of long circulation via monitoring of integral polymeric nanoparticles justifies a more accurate understanding

Monitoring of payloads results in a biased perception of long circulation of nanoparticles. Instead, herein, the long-circulation effect was re-confirmed by monitoring integral nanoparticles, but circulation was not found to be as long as generally perceived. In contrast, disparate pharmacokinetics were obtained by monitoring a model drug, paclitaxel, highlighting the bias of the conventional protocol.

Antitumor activity of a molecularly imprinted nanopreparation of 5-flurouracil against Ehrlich's carcinoma solid tumors grown in mice: Comparison to free 5-flurouracil

Recently, nanotechnology has received great attention in war against cancer. The present study investigated the antitumor efficacy of molecularly imprinted nanopreparation of 5-fluorouracil (nano-5-FU) against Ehrlich ascites carcinoma (EAC) solid tumors grown in mice. Tumor cells were transplanted into female albino mice. Mice were allocated into 5 groups; Group 1: control EAC bearing mice. Groups 2&3: EAC-bearing mice treated orally with 5-FU (5 and 10 mg/kg) twice weekly. Groups 4&5: EAC bearing mice treated with nano-5-FU (5 and 10 mg/kg) twice weekly. Treatment with nano-5-FU showed higher antitumor effect compared to free 5-FU as indicated by enhanced apoptosis and reduction in tumor weight. Additionally, lower number of mitotic figures and greater area for necrosis were observed in the tumor specimens alongside with a decline in the number of intratumoral proliferating nuclei in comparison to free 5-FU. Furthermore, the results showed a significant down-regulation in tumoral expression of caspase-3 and vascular endothelial growth factor. Together, these results further support the potential of using nanotechnology to enhance anticancer efficacy of 5-FU.

The Hippo pathway as a drug target in gastric cancer

The Hippo tumor suppressor pathway is critical for balancing cellular differentiation and proliferation in response to cell-cell contact, mechanical signals and diffusible signals such as lysophosphatidic acid. Hippo pathway signaling is frequently dysregulated in gastric cancer (GC), as well as many other kinds of solid tumors, contributing to multiple aspects of malignant progression including unchecked cell division and metastasis. Considering the importance of this Hippo pathway in cancer, its pharmacological disruption may be of huge benefit in the fight against this disease. In this review, we summarize the components of the Hippo pathway, its crosstalk with other major oncogenic signaling pathways, common mechanisms of its dysregulation, as well as potential therapeutic approaches of targeting this pathway for cancer treatment, specifically in a GC context.

Enzyme-Linked Immunosorbent Assay to Quantify Targeting Molecules on Nanoparticles

Molecular targeting presents a promising means of improving the specificity of cancer therapeutics, increasing accumulation at the cancer site and limiting off-target effects. These targeting schemes can be applied to nanoparticle-based treatments to further enhance their anticancer efficacy. Here, we describe methods to conjugate antibodies to silica-gold nanoshells and to quantify the resulting antibody content on the nanoparticles using a solution-based enzyme-linked immunosorbent assay (ELISA). Although we will be using anti-EGFR (epidermal growth factor receptor) antibodies conjugated to gold-silica nanoshells as a model system, this method is adaptable to quantify a range of targeting antibodies and proteins on various types of nanoparticles.

Targeting Strategies for the Combination Treatment of Cancer Using Drug Delivery Systems

Cancer cells have characteristics of acquired and intrinsic resistances to chemotherapy treatment-due to the hostile tumor microenvironment-that create a significant challenge for effective therapeutic regimens. Multidrug resistance, collateral toxicity to normal cells, and detrimental systemic side effects present significant obstacles, necessitating alternative and safer treatment strategies. Traditional administration of chemotherapeutics has demonstrated minimal success due to the non-specificity of action, uptake and rapid clearance by the immune system, and subsequent metabolic alteration and poor tumor penetration. Nanomedicine can provide a more effective approach to targeting cancer by focusing on the vascular, tissue, and cellular characteristics that are unique to solid tumors. Targeted methods of treatment using nanoparticles can decrease the likelihood of resistant clonal populations of cancerous cells. Dual encapsulation of chemotherapeutic drug allows simultaneous targeting of more than one characteristic of the tumor. Several first-generation, non-targeted nanomedicines have received clinical approval starting with Doxil® in 1995. However, more than two decades later, second-generation or targeted nanomedicines have yet to be approved for treatment despite promising results in pre-clinical studies. This review highlights recent studies using targeted nanoparticles for cancer treatment focusing on approaches that target either the tumor vasculature (referred to as 'vascular targeting'), the tumor microenvironment ('tissue targeting') or the individual cancer cells ('cellular targeting'). Recent studies combining these different targeting methods are also discussed in this review. Finally, this review summarizes some of the reasons for the lack of clinical success in the field of targeted nanomedicines.

In vitro microfluidic models of tumor microenvironment to screen transport of drugs and nanoparticles

Advances in nanotechnology have enabled numerous types of nanoparticles (NPs) to improve drug delivery to tumors. While many NP systems have been proposed, their clinical translation has been less than anticipated primarily due to failure of current preclinical evaluation techniques to adequately model the complex interactions between the NP and physiological barriers of tumor microenvironment. This review focuses on microfluidic tumor models for characterization of delivery efficacy and toxicity of cancer nanomedicine. Microfluidics offer significant advantages over traditional macroscale cell cultures by enabling recapitulation of tumor microenvironment through precise control of physiological cues such as hydrostatic pressure, shear stress, oxygen, and nutrient gradients. Microfluidic systems have recently started to be adapted for screening of drugs and NPs under physiologically relevant settings. So far the two primary application areas of microfluidics in this area have been high-throughput screening using traditional culture settings such as single cells or multicellular tumor spheroids, and mimicry of tumor microenvironment for study of cancer-related cell-cell and cell-matrix interactions. These microfluidic technologies are also useful in modeling specific steps in NP delivery to tumor and characterize NP transport properties and outcomes by systematic variation of physiological conditions. Ultimately, it will be possible to design drug-screening platforms uniquely tailored for individual patient physiology using microfluidics. These in vitro models can contribute to development of precision medicine by enabling rapid and patient-specific evaluation of cancer nanomedicine. WIREs Nanomed Nanobiotechnol 2017, 9:e1460. doi: 10.1002/wnan.1460 For further resources related to this article, please visit the WIREs website.

Cytotoxicological pathways induced after nanoparticle exposure: studies of oxidative stress at the 'nano-bio' interface

Nanotechnology is advancing rapidly; many industries are utilizing nanomaterials because of their remarkable properties. As of 2017, over 1800 "nano-enabled products" (i.e. products that incorporate a nanomaterial feature and alter the product's performance) have been used to revolutionize pharmaceutical, transportation, and agriculture industries, just to name a few. As the number of nano-enabled products continues to increase, the risk of nanoparticle exposure to humans and the surrounding environment also increases. These exposures are usually classified as either intentional or unintentional. The increased rate of potential nanoparticle exposure to humans has required the field of 'nanotoxicology' to rapidly screen for key biological, biochemical, chemical, or physical signals, signatures, or markers associated with specific toxicological pathways of injury within in vivo, in vitro, and ex vivo models. One of the common goals of nanotoxicology research is to identify critical perturbed biological pathways that can lead to an adverse outcome. This review focuses on the most common toxicological pathways induced by nanoparticle exposure and provides insights into how these perturbations could aid in the development of nanomaterial specific adverse outcomes, inform nano-enabled product development, ensure safe manufacturing practices, promote intentional product use, and avoid environmental health hazards.

Fusion peptide functionalized hybrid nanoparticles for synergistic drug delivery to reverse cancer drug resistance

A facile self-assembly strategy was developed to decorate polymer/inorganic hybrid nano-sized drug delivery systems with functional peptides. To enhance drug delivery efficacy and overcome tumor drug resistance, a functional fusion peptide containing an RGD sequence for tumor targeting and an R₈ sequence for cell penetration was introduced onto the surface of biotinylated carboxymethyl chitosan/CaCO₃ (BCMC/CaCO₃) hybrid nanoparticles through biotin-avidin interaction to obtain peptide functionalized nanoparticles (PNP). The peptide functionalization results in improved delivery efficiency and effective inhibition for drug resistant tumor cells. Co-delivery of an anti-cancerous drug (doxorubicin hydrochloride, DOX) and a cyclooxygenase-2 inhibitor (celecoxib, CXB) by PNP can further improve the therapeutic efficiency by effectively down-regulating P-gp expression to reduce P-gp mediated drug efflux and increase intracellular drug accumulation.

Rational Design of Cancer Nanomedicine: Nanoproperty Integration and Synchronization

Current cancer nanomedicines can only mitigate adverse effects but fail to enhance therapeutic efficacies of anticancer drugs. Rational design of next-generation cancer nanomedicines should aim to enhance their therapeutic efficacies. Taking this into account, this review first analyzes the typical cancer-drug-delivery process of an intravenously administered nanomedicine and concludes that the delivery involves a five-step CAPIR cascade and that high efficiency at every step is critical to guarantee high overall therapeutic efficiency. Further analysis shows that the nanoproperties needed in each step for a nanomedicine to maximize its efficiency are different and even opposing in different steps, particularly what the authors call the PEG, surface-charge, size and stability dilemmas. To resolve those dilemmas in order to integrate all needed nanoproperties into one nanomedicine, stability, surface and size nanoproperty transitions (3S transitions for short) are proposed and the reported strategies to realize these transitions are comprehensively summarized. Examples of nanomedicines capable of the 3S transitions are discussed, as are future research directions to design high-performance cancer nanomedicines and their clinical translations.