The complex role of multivalency in nanoparticles targeting the transferrin receptor for cancer therapies

PSMA-targeted combination brusatol and docetaxel nanotherapeutics for the treatment of prostate cancer

Active targeting to cancer involves exploiting specific interactions between receptors on the surface of cancer cells and targeting moieties conjugated to the surface of vectors such that site-specific delivery is achieved. Prostate specific membrane antigen (PSMA) has proved to be an excellent target for active targeting to prostate cancer. We report the synthesis and use of a PSMA-specific ligand (Glu-NH-CO-NH-Lys) for the site-specific delivery of brusatol- and docetaxel-loaded poly(lactide-co-glycolide) (PLGA) nanoparticles to prostate cancer. The PSMA targeting ligand covalently linked to PLGA-PEG3400 was blended with methoxyPEG-PLGA to prepare brusatol- and docetaxel-loaded nanoparticles with different surface densities of the targeting ligand. Flow cytometry was used to evaluate the impact of different surface densities of the PSMA targeting ligand in LNCaP prostate cancer cells at 15 min and 2 h. Cytotoxicity evaluations of the targeted nanoparticles reveal differences based on PSMA expression in PC-3 and LNCaP cells. In addition, levels of reactive oxygen species (ROS) were measured using the fluorescent indicator, H2DCFDA, by flow cytometry. PSMA-targeted nanoparticles loaded with docetaxel and brusatol showed increased ROS generation in LNCaP cells compared to PC-3 at different time points. Furthermore, the targeted nanoparticles were evaluated in male athymic BALB/c mice implanted with PSMA-producing LNCaP cell tumors. Evaluation of the percent relative tumor volume show that brusatol-containing nanoparticles show great promise in inhibiting tumor growth. Our data also suggest that the dual drug-loaded targeted nanoparticle platform improves the efficacy of docetaxel in male athymic BALB/c mice implanted with PSMA-producing LNCaP cell tumors.

Valency of Ligand-Receptor Binding from Pair Potentials

Coarse grained molecular dynamics simulations have been crucial for investigating the dynamics of nanoparticle uptake by cell membranes via ligand-receptor interactions. These models have enabled researchers to evaluate the effects of nanoparticle size, shape, and ligand distribution on cellular uptake. However, when pair potentials are used to represent ligand-receptor interactions, the number of receptors interacting with one ligand, valency, may vary. We demonstrate that the curvature of a nanoparticle, strength of ligand-receptor interactions, and ligand or receptor concentration change the valency, ranging from 3.4 to 5.1 in this study. Such a change in valency can create inaccurate comparisons between nanoparticles or even result in the uptake of smaller nanoparticles than would be expected. To rectify this inconsistency, we propose the adoption of a model based on bond formation and use it to determine the extent to which previous studies may have been affected. This work recommends avoiding pair potentials for modeling ligand-receptor interactions to ensure methodological consistency in nanoparticle studies.

Active nanoparticle targeting of MUC5AC ameliorates therapeutic outcome in experimental colitis

Inflammatory bowel diseases (IBDs), which include Crohn's disease (CD) and ulcerative colitis (UC), are chronic inflammatory diseases of the gastrointestinal tract and are characterized by chronic recurrent ulceration of the bowels. Colon-targeted drug delivery systems (DDS) have received significant attention for their potential to treat IBD by improving the inflamed tissue selectivity. Herein, antiMUC5AC-decorated drug loaded nanoparticles (NP) are suggested for active epithelial targeting and selective adhesion to the inflamed tissue in experimental colitis. NPs conjugated with antiMUC5AC (anti-MUC5) were tested for their degree of bioadhesion with HT29-MTX cells by comparison with non-targeted BSA-NP conjugates. In vivo, the selectivity of bioadhesion and the influence of ligand density in bioadhesion efficiency as well as the therapeutic benefit for glucocorticoid loaded anti-MUC5-NP were studied in a murine colitis model. Quantitative adhesion analyses showed that anti-MUC5-conjugated NP exhibited a much higher binding and selectivity to inflamed tissue compared to PNA-, IgG1- and BSA-NP conjugates used as controls. This bioadhesion efficiency was found to be dependent on the ligand density, present at the NP surface. The binding specificity between anti-MUC5 ligand and inflamed tissues was confirmed by fluorescence imaging. Both anti-MUC5-NP and all other glucocorticoid containing formulations led to a significant mitigation of the experimental colitis, as became evident from the substantial reduction of myeloperoxidase activity and pro-inflammatory cytokine concentrations (TNF-α, IL-1β). Targeted NP by using anti-MUC5 appears to be a very promising tool in future treatment of various types of local disorders affecting the gastro-intestinal tract but not limited to colitis.

Multivariate Analysis of Cellular Uptake Characteristics for a (Co)polymer Particle Library

Controlling cellular responses to nanoparticles so far is predominantly empirical, typically requiring multiple rounds of optimization of particulate carriers. In this study, a systematic model-assisted approach should lead to the identification of key parameters that account for particle properties and their cellular recognition. A copolymer particle library was synthesized by a combinatorial approach in soap free emulsion copolymerization of styrene and methyl methacrylate, leading to a broad compositional as well as constitutional spectrum. The proposed structure-property relationships could be elucidated by multivariate analysis of the obtained experimental data, including physicochemical characteristics such as molar composition, molecular weight, particle diameter, and particle charge as well as the cellular uptake pattern of nanoparticles. It was found that the main contributors for particle size were the polymers' molecular weight and the zeta potential, while particle uptake is mainly directed by the particles' composition. This knowledge and the reported model-assisted procedure to identify relevant parameters affecting particle engulfment of particulate carriers by nonphagocytic and phagocytic cells can be of high relevance for the rational design of pharmaceutical nanocarriers and assessment of biodistribution and nanotoxicity, respectively.

Bone Targeting Nanoparticles for the Treatment of Osteoporosis

Osteoporosis (OP) affects millions of people worldwide, especially postmenopausal women and the elderly. Although current available anti-OP agents can show promise in slowing down bone resorption, most are not specifically delivered to the hard tissue, causing significant toxicity. A bone-targeted nanodrug delivery system can reduce side effects and precisely deliver drug candidates to the bone. This review focuses on the progress of bone-targeted nanoparticles in OP therapy. We enumerate the existing OP medications, types of bone-targeted nanoparticles and categorize pairs of the most common bone-targeting functional groups. Finally, we summarize the potential use of bone-targeted nanoparticles in OP treatment. Ongoing research into the development of targeted ligands and nanocarriers will continue to expand the possibilities of OP-targeted therapies into clinical application.

Magnetic nanoparticles for ferroptosis cancer therapy with diagnostic imaging

Ferroptosis offers a novel method for overcoming therapeutic resistance of cancers to conventional cancer treatment regimens. Its effective use as a cancer therapy requires a precisely targeted approach, which can be facilitated by using nanoparticles and nanomedicine, and their use to enhance ferroptosis is indeed a growing area of research. While a few review papers have been published on iron-dependent mechanism and inducers of ferroptosis cancer therapy that partly covers ferroptosis nanoparticles, there is a need for a comprehensive review focusing on the design of magnetic nanoparticles that can typically supply iron ions to promote ferroptosis and simultaneously enable targeted ferroptosis cancer nanomedicine. Furthermore, magnetic nanoparticles can locally induce ferroptosis and combinational ferroptosis with diagnostic magnetic resonance imaging (MRI). The use of remotely controllable magnetic nanocarriers can offer highly effective localized image-guided ferroptosis cancer nanomedicine. Here, recent developments in magnetically manipulable nanocarriers for ferroptosis cancer nanomedicine with medical imaging are summarized. This review also highlights the advantages of current state-of-the-art image-guided ferroptosis cancer nanomedicine. Finally, image guided combinational ferroptosis cancer therapy with conventional apoptosis-based therapy that enables synergistic tumor therapy is discussed for clinical translations.

Application of Nanoparticles in Cancer Treatment: A Concise Review

Timely diagnosis and appropriate antitumoral treatments remain of utmost importance, since cancer remains a leading cause of death worldwide. Within this context, nanotechnology offers specific benefits in terms of cancer therapy by reducing its adverse effects and guiding drugs to selectively target cancer cells. In this comprehensive review, we have summarized the most relevant novel outcomes in the range of 2010-2023, covering the design and application of nanosystems for cancer therapy. We have established the general requirements for nanoparticles to be used in drug delivery and strategies for their uptake in tumor microenvironment and vasculature, including the reticuloendothelial system uptake and surface functionalization with protein corona. After a brief review of the classes of nanovectors, we have covered different classes of nanoparticles used in cancer therapies. First, the advances in the encapsulation of drugs (such as paclitaxel and fisetin) into nanoliposomes and nanoemulsions are described, as well as their relevance in current clinical trials. Then, polymeric nanoparticles are presented, namely the ones comprising poly lactic-co-glycolic acid, polyethylene glycol (and PEG dilemma) and dendrimers. The relevance of quantum dots in bioimaging is also covered, namely the systems with zinc sulfide and indium phosphide. Afterwards, we have reviewed gold nanoparticles (spheres and anisotropic) and their application in plasmon-induced photothermal therapy. The clinical relevance of iron oxide nanoparticles, such as magnetite and maghemite, has been analyzed in different fields, namely for magnetic resonance imaging, immunotherapy, hyperthermia, and drug delivery. Lastly, we have covered the recent advances in the systems using carbon nanomaterials, namely graphene oxide, carbon nanotubes, fullerenes, and carbon dots. Finally, we have compared the strategies of passive and active targeting of nanoparticles and their relevance in cancer theranostics. This review aims to be a (nano)mark on the ongoing journey towards realizing the remarkable potential of different nanoparticles in the realm of cancer therapeutics.

Hydrogen Sulfide Responsive Phototherapy Agents: Design Strategies and Biological Applications

Hydrogen sulfide (H2S) is one of the critical gasotransmitters, which play important roles in regular physiological processes, especially in vital signaling pathways. However, fluctuations in endogenous H2S concentration can be linked to serious health problems, such as neurodegenerative diseases, cancer, diabetes, inflammation, cardiovascular diseases, and hypertension. Thus, it has attracted a great deal of attention in therapeutic applications, specifically in the field of phototherapy. Photodynamic therapy (PDT) and photothermal therapy (PTT) are two subclasses of phototherapy, which utilize either reactive oxygen species (ROS) or local temperature increase upon irradiation of a photosensitizer (PS) to realize the therapeutic action. Phototherapies offer unique advantages compared to conventional methods; thus, they are highly promising and popular. One of the design principles followed in new generation PSs is to build activity-based PSs, which stay inactive before getting activated by disease-associated stimuli. These activatable PSs dramatically improve the selectivity and efficacy of the therapy. In this review, we summarize small molecule and nanomaterial-based PDT and PTT agents that are activated selectively by H2S to initiate their cytotoxic effect. We incorporate single mode PDT and PTT agents along with synergistic and/or multimodal photosensitizers that can combine more than one therapeutic approach. Additionally, H2S-responsive theranostic agents, which offer therapy and imaging at the same time, are highlighted. Design approaches, working principles, and biological applications for each example are discussed in detail.

Ultrasonic Transformation of Antibiotic Molecules into a Selective Chemotherapeutic Nanodrug

Ultrasound-based engineering of carrier-free nanodrugs by supramolecular self-assembly has recently emerged as an innovative and environmentally friendly synthetic approach. By applying high-frequency sound waves (490 kHz) in aqueous solutions, the transformation of small chemotherapeutic and antibiotic drug molecules into carrier-free nanodrugs with anticancer and antimicrobial activities was recently achieved. The transformation of the antibiotic drug molecules, i.e., doxycycline, into stable nanodrugs (~130 nm) with selective anticancer activity was achieved without requiring organic solvents, chemical agents, or surfactants. The obtained nanodrug exhibited reactive oxygen species (ROS)-mediated cytotoxicity on human breast cancer (MDA-MB 231 cells) but a negligible antiproliferative effect on healthy fibroblast cells. Imaging by super-resolution microscopy (STORM) provided insights into the intracellular trafficking and endosomal escape of the nanodrugs. Overall, these findings suggest that small antibiotic drugs can be transformed into chemotherapeutic nanodrugs with high selectivity against cancer cells.

Ligand Installation to Polymeric Micelles for Pediatric Brain Tumor Targeting

Medulloblastoma is a life-threatening disease with poor therapeutic outcomes. In chemotherapy, low drug accumulation has been a cause of these outcomes. Such inadequate response to treatments has been associated with low drug accumulation, particularly with a limited cellular uptake of drugs. Recently, the conjugation of drugs to ligand molecules with high affinity to tumor cells has attracted much attention for enhancing drug internalization into target cells. Moreover, combining tumor-targeting ligands with nano-scaled drug carriers can potentially improve drug loading capacity and the versatility of the delivery. Herein, we focused on the possibility of targeting CD276/B7-H3, which is highly expressed on the medulloblastoma cell membrane, as a strategy for enhancing the cellular uptake of ligand-installed nanocarriers. Thus, anti-CD276 antibodies were conjugated on the surface of model nanocarriers based on polyion complex micelles (PIC/m) via click chemistry. The results showed that the anti-CD276 antibody-installed PIC/m improved intracellular delivery into CD276-expressing medulloblastoma cells in a CD276-dependent manner. Moreover, increasing the number of antibodies on the surface of micelles improved the cellular uptake efficiency. These observations indicate the potential of anti-CD276 antibody-installed nanocarriers for promoting drug delivery in medulloblastoma.

Barrier permeation and improved nanomedicine delivery in tumor microenvironments

Nanomedicines can effectively penetrate tumor sites compared to traditionally used drugs. However, effective drugs that reach the interior of tumors remain limited. Based on studies of the complex tumor microenvironment, we summarized the barriers restricting tumor penetration of nanomedicines in this review. Penetration barriers are mainly caused by tumor blood vessels, stroma, and cell abnormalities. The repair of abnormal tumor blood vessels and tumor stroma and adjusting the physicochemical properties of nanoparticles are considered promising strategies to improve the tumor permeation of nanomedicines. The effects of nanoparticle properties, including size, shape, and surface charge, on tumor penetration were also reviewed. We expect to provide research ideas and a scientific basis for nanomedicines to increase intratumoral permeability and improve anti-tumor effects.

Lipid-core nanoparticles: Classification, preparation methods, routes of administration and recent advances in cancer treatment

Nanotechnological drug delivery platforms represent a new paradigm for cancer therapeutics as they improve the pharmacokinetic profile and distribution of chemotherapeutic agents over conventional formulations. Among nanoparticles, lipid-based nanoplatforms possessing a lipid core, that is, lipid-core nanoparticles (LCNPs), have gained increasing interest due to lipid properties such as high solubilizing potential, versatility, biocompatibility, and biodegradability. However, due to the wide spectrum of morphologies and types of LCNPs, there is a lack of consensus regarding their terminology and classification. According to the current state-of-the-art in this critical review, LCNPs are defined and classified based on the state of their lipidic components in liquid lipid nanoparticles (LLNs). These include lipid nanoemulsions (LNEs) and lipid nanocapsules (LNCs), solid lipid nanoparticles (SLNs) and nanostructured lipid nanocarriers (NLCs). In addition, we present a comprehensive and comparative description of the methods employed for their preparation, routes of administration and the fundamental role of physicochemical properties of LCNPs for efficient antitumoral drug-delivery application. Market available LCNPs, clinical trials and preclinical in vivo studies of promising LCNPs as potential treatments for different cancer pathologies are summarized.

Influence of Folate-Targeted Gold Nanoparticles on Subcellular Localization and Distribution into Lysosomes

The cell interaction, mechanism of cell entry and intracellular fate of surface decorated nanoparticles are known to be affected by the surface density of targeting agents. However, the correlation between nanoparticles multivalency and kinetics of the cell uptake process and disposition of intracellular compartments is complicated and dependent on a number of physicochemical and biological parameters, including the ligand, nanoparticle composition and colloidal properties, features of targeted cells, etc. Here, we have carried out an in-depth investigation on the impact of increasing folic acid density on the kinetic uptake process and endocytic route of folate (FA)-targeted fluorescently labelled gold nanoparticles (AuNPs). A set of AuNPs (15 nm mean size) produced by the Turkevich method was decorated with 0–100 FA-PEG3.5kDa-SH molecules/particle, and the surface was saturated with about 500 rhodamine-PEG2kDa-SH fluorescent probes. In vitro studies carried out using folate receptor overexpressing KB cells (KBFR-high) showed that the cell internalization progressively increased with the ligand surface density, reaching a plateau at 50:1 FA-PEG3.5kDa-SH/particle ratio. Pulse-chase experiments showed that higher FA density (50 FA-PEG3.5kDa-SH molecules/particle) induces more efficient particle internalization and trafficking to lysosomes, reaching the maximum concentration in lysosomes at 2 h, than the lower FA density of 10 FA-PEG3.5kDa-SH molecules/particle. Pharmacological inhibition of endocytic pathways and TEM analysis showed that particles with high folate density are internalized predominantly by a clathrin-independent process.

Transferrin-modified chitosan nanoparticles for targeted nose-to-brain delivery of proteins

Nose-to-brain delivery presents a promising alternative route compared to classical blood-brain barrier passage, especially for the delivery of high molecular weight drugs. In general, macromolecules are rapidly degraded in physiological environment. Therefore, nanoparticulate systems can be used to protect biomolecules from premature degradation. Furthermore, targeting ligands on the surface of nanoparticles are able to improve bioavailability by enhancing cellular uptake due to specific binding and longer residence time. In this work, transferrin-decorated chitosan nanoparticles are used to evaluate the passage of a model protein through the nasal epithelial barrier in vitro. It was demonstrated that strain-promoted azide-alkyne cycloaddition reaction can be utilized to attach a functional group to both transferrin and chitosan enabling a rapid covalent surface-conjugation under mild reaction conditions after chitosan nanoparticle preparation. The intactness of transferrin and its binding efficiency were confirmed via SDS-PAGE and SPR measurements. Resulting transferrin-decorated nanoparticles exhibited a size of about 110-150 nm with a positive surface potential. Nanoparticles with the highest amount of surface bound targeting ligand also displayed the highest cellular uptake into a human nasal epithelial cell line (RPMI 2650). In an air-liquid interface co-culture model with glioblastoma cells (U87), transferrin-decorated nanoparticles showed a faster passage through the epithelial cell layer as well as increased cellular uptake into glioblastoma cells. These findings demonstrate the beneficial characteristics of a specific targeting ligand. With this chemical and technological formulation concept, a variety of targeting ligands can be attached to the surface after nanoparticle formation while maintaining cargo integrity.

Brain-targeted exosome-mimetic cell membrane nanovesicles with therapeutic oligonucleotides elicit anti-tumor effects in glioblastoma animal models

The brain-targeted delivery of therapeutic oligonucleotides has been investigated as a new treatment modality for various brain diseases, such as brain tumors. However, delivery efficiency into the brain has been limited due to the blood-brain barrier. In this research, brain-targeted exosome-mimetic cell membrane nanovesicles (CMNVs) were designed to enhance the delivery of therapeutic oligonucleotides into the brain. First, CMNVs were produced by extrusion with isolated C6 cell membrane fragments. Then, CMNVs were decorated with cholesterol-linked T7 peptides as a targeting ligand by hydrophobic interaction, producing T7-CMNV. T7-CMNV was in aqueous solution maintained its nanoparticle size for over 21 days. The targeting and delivery effects of T7-CMNVs were evaluated in an orthotopic glioblastoma animal model. 2'-O-metyl and cholesterol-TEG modified anti-microRNA-21 oligonucleotides (AMO21c) were loaded into T7-CMNVs, and biodistribution experiments indicated that T7-CMNVs delivered AMO21c more efficiently into the brain than CMNVs, scrambled T7-CMNVs, lipofectamine, and naked AMO21c after systemic administration. In addition, AMO21c down-regulated miRNA-21 (miR-21) levels in glioblastoma tissue most efficiently in the T7-CMNVs group. This enhanced suppression of miR-21 resulted in the up-regulation of PDCD4 and PTEN. Eventually, brain tumor size was reduced in the T7-CMNVs group more efficiently than in the other control groups. With stability, low toxicity, and targeting efficiency, T7-CMNVs may be useful to the development of oligonucleotide therapy for brain tumors.

Nano-Enabled Strategies for the Treatment of Lung Cancer: Potential Bottlenecks and Future Perspectives

On a global scale, lung cancer is acknowledged to be the major driver of cancer death attributable to treatment challenges and poor prognosis. Classical cancer treatment regimens, such as chemotherapy or radiotherapy, can be used to treat lung cancer, but the appended adverse effects limit them. Because of the numerous side effects associated with these treatment modalities, it is crucial to strive to develop novel and better strategies for managing lung cancer. Attributes such as enhanced bioavailability, better in vivo stability, intestinal absorption pattern, solubility, prolonged and targeted distribution, and the superior therapeutic effectiveness of numerous anticancer drugs have all been boosted with the emergence of nano-based therapeutic systems. Lipid-based polymeric and inorganic nano-formulations are now being explored for the targeted delivery of chemotherapeutics for lung cancer treatment. Nano-based approaches are pioneering the route for primary and metastatic lung cancer diagnosis and treatment. The implementation and development of innovative nanocarriers for drug administration, particularly for developing cancer therapies, is an intriguing and challenging task in the scientific domain. The current article provides an overview of the delivery methods, such as passive and active targeting for chemotherapeutics to treat lung cancer. Combinatorial drug therapy and techniques to overcome drug resistance in lung cancer cells, as potential ways to increase treatment effectiveness, are also discussed. In addition, the clinical studies of the potential therapies at different stages and the associated challenges are also presented. A summary of patent literature has also been included to keep readers aware of the new and innovative nanotechnology-based ways to treat lung cancer.

Ferroptosis and Its Potential Role in Glioma: From Molecular Mechanisms to Therapeutic Opportunities

Glioma is the most common intracranial malignant tumor, and the current main standard treatment option is a combination of tumor surgical resection, chemotherapy and radiotherapy. Due to the terribly poor five-year survival rate of patients with gliomas and the high recurrence rate of gliomas, some new and efficient therapeutic strategies are expected. Recently, ferroptosis, as a new form of cell death, has played a significant role in the treatment of gliomas. Specifically, studies have revealed key processes of ferroptosis, including iron overload in cells, occurrence of lipid peroxidation, inactivation of cysteine/glutathione antiporter system Xc- (xCT) and glutathione peroxidase 4 (GPX4). In the present review, we summarized the molecular mechanisms of ferroptosis and introduced the application and challenges of ferroptosis in the development and treatment of gliomas. Moreover, we highlighted the therapeutic opportunities of manipulating ferroptosis to improve glioma treatments, which may improve the clinical outcome.

2D Copper(II) Metalated Metal-Organic Framework Nanocomplexes for Dual-enhanced Photodynamic Therapy and Amplified Antitumor Immunity

The immunosuppressive tumor microenvironment (TME) poses tremendous challenges for efficient immunotherapy. Smart nanomedicine is designed to modulate immunosuppressive TMEs based on the combination of dual-enhanced photodynamic therapy (PDT) triggered immunogenic cell death (ICD) and relieved hypoxic microenvironment. Copper(II) metalated metal-organic framework nanosheets (Cu-TCPP(Al)) are the foundation of the nanomedicine, and platinum nanoparticles (Pt NPs) and folate are subsequently introduced onto the Cu-TCPP(Al) surface (Cu-TCPP(Al)-Pt-FA). Upon targeted cellular uptake, intracellular GSH concentration is decreased because of the specific adsorption between GSH and Cu^II; meanwhile, Pt NPs possess catalase-like activity, which can continuously depose intracellular H₂O₂ to O₂ to alleviate the hypoxic TME. The two factors synergistically improve the ROS concentration for dual-enhanced PDT. The highly toxic ROS can correspondingly cause amplified oxidative stress and then trigger the ICD. The ICD process stimulates antigen-presenting cells and activates the systemic antitumor immune response. Furthermore, the relieved hypoxic TME increases the infiltration of cytotoxic T lymphocytes (CTLs) at the tumor site, which can promote the transformation of the immunosuppressive M2 macrophage to immunoactive M1 phenotype. The easily prepared yet versatile nanomedicine possesses an excellent antitumor effect with the cooperation of dual-enhanced PDT and immunotherapy.

Multivalent Ligand-Nanoparticle Conjugates Amplify Reactive Oxygen Species Second Messenger Generation and Enhance Epidermal Growth Factor Receptor Phosphorylation

The epidermal growth factor (EGF) receptor (EGFR) is heterogeneously distributed on the cellular surface and enriched in clusters with diameters of tens of nanometers. Multivalent presentation of EGF ligand on nanoparticles (NPs) provides an approach for controlling and amplifying the local activation of EGFR in these clusters. Reactive oxygen species (ROS) have been indicated to play a role in the regulation of EGFR activation as second messengers, but the effect of nanoconjugation on EGF-mediated ROS formation and ROS-induced EGFR activation is not well established. The goal of this manuscript is to characterize the multivalent enhancement of EGF-induced ROS formation and to test its effect on EGFR phosphorylation in breast cancer cell models using gold (Au) NPs with a diameter of 81 ± 1 nm functionalized with two different EGF ligand densities (12 ± 7 EGF/NP (NP-EGF12) and 87 ± 6 EGF/NP (NP-EGF87)). In the EGFR overexpressing cell lines MDA-MB-231 and MDA-MB-468, NP-EGF87 achieved a measurable multivalent enhancement of ROS that peaked at concentrations c ROSmax ≤ 25 pM and that were EGFR and nicotinamide adenine dinucleotide phosphate oxidase (NOX) dependent. NP-EGF12 failed to generate comparable ROS levels as NP-EGF87 in the investigated NP input concentration range (0-100 pM). In cells with nearly identical numbers of bound NP-EGF87 and NP-EGF12, the ROS levels for NP-EGF87 were systematically higher, indicating that the multivalent enhancement is exclusively related not only to avidity but also to a stronger stimulation per NP. Importantly, the increase in EGF-induced ROS formation associated with EGF nanoconjugation at c ROSmax resulted in a measurable gain in EGFR phosphorylation, confirming that ROS generation contributes to the multivalent enhancement of EGFR activation in response to NP-EGF87.

Applications of Fluorescent Nanodiamond in Biology

Fluorescent nanodiamond (FND) has emerged as a promising material in several multidisciplinary areas, including biology, chemistry, physics, and materials science. Composed of sp 3 ‐carbon atoms, FND offers superior biocompatibility, chemical inertness, a large surface area, tunable surface structure, and excellent mechanical characteristics. The nanoparticle is unique in that it comprises a high‐density ensemble of negatively charged nitrogen‐vacancy (NV − ) centers that act as built‐in fluorophores and exhibit a number of remarkable optical and magnetic properties. These properties make FND particularly well suited for a wide range of applications, including cell labeling, long‐term cell tracking, super‐resolution imaging, nanoscale sensing, and drug delivery. This article discusses recent applications of FND‐enabled developments in biology.

Conformationally engineering flexible peptides on silver nanoparticles

Molecular conformational engineering is to engineer flexible non-functional molecules into unique conformations to create novel functions just like natural proteins fold. Obviously, it is a grand challenge with tremendous opportunities. Based on the facts that natural proteins are only marginally stable with a net stabilizing energy roughly equivalent to the energy of two hydrogen bonds, and the energy barriers for the adatom diffusion of some metals are within a similar range, we propose that metal nanoparticles can serve as a general replacement of protein scaffolds to conformationally engineer protein fragments on the surface of nanoparticles. To prove this hypothesis, herein, we successfully restore the antigen-recognizing function of the flexible peptide fragment of a natural anti-lysozyme antibody on the surface of silver nanoparticles, creating a silver nanoparticle-base artificial antibody (Silverbody). A plausible mechanism is proposed, and some general principles for conformational engineering are summarized to guide future studies in this area.

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A silver NP-based artificial antibody is created by conformational engineering

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Function emerges on NPs from non-functional peptide by mimicking the protein folding

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A general mechanism is proposed for the conformational engineering on metal NPs

Different Serum, Different Protein Corona! The Impact of the Serum Source on Cellular Targeting of Folic Acid-Modified Chitosan-Based Nanoparticles

The nanoparticle (NP) protein corona represents an interface between biological components and NPs, dictating their cellular interaction and biological fate. To assess the success of cellular targeting, NPs modified with targeting ligands are incubated with target cells in serum-free culture medium or in the presence of fetal bovine serum (FBS). In the former, the role of the corona is overlooked, and in the latter, the effects of a corona that does not represent the one forming in humans nor the respective disease state are considered. Via proteomic analysis, we demonstrate how the difference in the composition of FBS, sera from healthy human volunteers, and breast cancer patients (BrCr Pt) results in the formation of completely different protein coronas around the same NP. Successful in vitro targeting of breast cancer cells was only observed when NPs were incubated with target cells in the presence of BrCr Pt sera only. In such cases, the success of targeting was not attributed to the targeting ligand itself, but to the adsorption of specific serum proteins that facilitate NP uptake by cancer cells in the presence of BrCr Pt sera. This work therefore demonstrates how the serum source affects the reliability of in vitro experiments assessing NP-cell interactions and the consequent success or failure of active targeting and may in fact indicate an additional reason for the limited clinical success of drug targeting by NPs in cancer.

A Single-Molecule View at Nanoparticle Targeting Selectivity: Correlating Ligand Functionality and Cell Receptor Density

Antibody-functionalized nanoparticles (NPs) are commonly used to increase the targeting selectivity toward cells of interest. At a molecular level, the number of functional antibodies on the NP surface and the density of receptors on the target cell determine the targeting interaction. To rationally develop selective NPs, the single-molecule quantitation of both parameters is highly desirable. However, techniques able to count molecules with a nanometric resolution are scarce. Here, we developed a labeling approach to quantify the number of functional cetuximabs conjugated to NPs and the expression of epidermal growth factor receptors (EGFRs) in breast cancer cells using direct stochastic optical reconstruction microscopy (dSTORM). The single-molecule resolution of dSTORM allows quantifying molecules at the nanoscale, giving a detailed insight into the distributions of individual NP ligands and cell receptors. Additionally, we predicted the fraction of accessible antibody-conjugated NPs using a geometrical model, showing that the total number exceeds the accessible number of antibodies. Finally, we correlated the NP functionality, cell receptor density, and NP uptake to identify the highest cell uptake selectivity regimes. We conclude that single-molecule functionality mapping using dSTORM provides a molecular understanding of NP targeting, aiding the rational design of selective nanomedicines.

The effect of AS1411 surface density on the tumor targeting properties of PEGylated silver nanotriangles

Aim: To determine the optimal AS1411 density on polyethylene glycol (PEG)ylated silver nanotriangles (PNTs) for targeting breast cancer cells. Methods: PNTs modified with different AS1411 densities (ANTs) were constructed, characterized and evaluated for their targeting properties in breast cancer cells and a mouse model of breast cancer. Results: AS1411 was successfully conjugated to PNTs. The accumulation and cellular uptake of 10-ANTs were the highest. 10-ANTs plus near-IR laser irradiation displayed the greatest inhibitory effect on cell viability. However, 5-ANTs had the highest accumulation in tumor tissues. When combined with NIR laser, 5-ANTs exhibited the best in vivo photothermal therapy effect. Conclusion: The optimal AS1411 densities at the cellular and animal levels were 10% and 5%, respectively.

New challenges in the use of nanomedicine in cancer therapy

Nanomedicines are applied as alternative treatments for anticancer agents. For the treatment of cancer, due to the small size in nanometers (nm), specific site targeting can be achieved with the use of nanomedicines, increasing their bioavailability and conferring fewer toxic side effects. Additionally, the use of minute amounts of drugs can lead to cost savings. In addition, nanotechnology is effectively applied in the preparation of such drugs as they are in nm sizes, considered one of the earliest cutoff values for the production of products utilized in nanotechnology. Early concepts described gold nanoshells as one of the successful therapies for cancer and associated diseases where the benefits of nanomedicine include effective active or passive targeting. Common medicines are degraded at a higher rate, whereas the degradation of macromolecules is time-consuming. All of the discussed properties are responsible for executing the physiological behaviors occurring at the following scale, depending on the geometry. Finally, large nanomaterials based on organic, lipid, inorganic, protein, and synthetic polymers have also been utilized to develop novel cancer cures.

Nanomedicines in B cell-targeting therapies

B cells play multiple roles in immune responses related to autoimmune diseases as well as different types of cancers. As such, strategies focused on B cell targeting attracted wide interest and developed intensively. There are several common mechanisms various B cell targeting therapies have relied on, including direct B cell depletion, modulation of B cell antigen receptor (BCR) signaling, targeting B cell survival factors, targeting the B cell and T cell costimulation, and immune checkpoint blockade. Nanocarriers, used as drug delivery vehicles, possess numerous advantages to low molecular weight drugs, reducing drug toxicity, enhancing blood circulation time, as well as augmenting targeting efficacy and improving therapeutic effect. Herein, we review the commonly used targets involved in B cell targeting approaches and the utilization of various nanocarriers as B cell-targeted delivery vehicles. STATEMENT OF SIGNIFICANCE: As B cells are engaged significantly in the development of many kinds of diseases, utilization of nanomedicines in B cell depletion therapies have been rapidly developed. Although numerous studies focused on B cell targeting have already been done, there are still various potential receptors awaiting further investigation. This review summarizes the most relevant studies that utilized nanotechnologies associated with different B cell depletion approaches, providing a useful tool for selection of receptors, agents and/or nanocarriers matching specific diseases. Along with uncovering new targets in the function map of B cells, there will be a growing number of candidates that can benefit from nanoscale drug delivery.

Current understandings and clinical translation of nanomedicines for breast cancer therapy

Breast cancer is one of the most frequently diagnosed cancers that is threatening women's life. Current clinical treatment regimens for breast cancer often involve neoadjuvant and adjuvant systemic therapies, which somewhat are associated with unfavorable features. Also, the heterogeneous nature of breast cancers requires precision medicine that cannot be fulfilled by a single type of systemically administered drug. Taking advantage of the nanocarriers, nanomedicines emerge as promising therapeutic agents for breast cancer that could resolve the defects of drugs and achieve precise drug delivery to almost all sites of primary and metastatic breast tumors (e.g. tumor vasculature, tumor stroma components, breast cancer cells, and some immune cells). Seven nanomedicines as represented by Doxil® have been approved for breast cancer clinical treatment so far. More nanomedicines including both non-targeting and active targeting nanomedicines are being evaluated in the clinical trials. However, we have to realize that the translation of nanomedicines, particularly the active targeting nanomedicines is not as successful as people have expected. This review provides a comprehensive landscape of the nanomedicines for breast cancer treatment, from laboratory investigations to clinical applications. We also highlight the key advances in the understanding of the biological fate and the targeting strategies of breast cancer nanomedicine and the implications to clinical translation.

Quantifying and controlling bond multivalency for advanced nanoparticle targeting to cells

Nanoparticles have drawn intense interest as delivery agents for diagnosing and treating various cancers. Much of the early success was driven by passive targeting mechanisms such as the enhanced permeability and retention (EPR) effect, but this has failed to lead to the expected clinical successes. Active targeting involves binding interactions between the nanoparticle and cancer cells, which promotes tumor cell-specific accumulation and internalization. Furthermore, nanoparticles are large enough to facilitate multiple bond formation, which can improve adhesive properties substantially in comparison to the single bond case. While multivalent binding is universally believed to be an attribute of nanoparticles, it is a complex process that is still poorly understood and difficult to control. In this review, we will first discuss experimental studies that have elucidated roles for parameters such as nanoparticle size and shape, targeting ligand and target receptor densities, and monovalent binding kinetics on multivalent nanoparticle adhesion efficiency and cellular internalization. Although such experimental studies are very insightful, information is limited and confounded by numerous differences across experimental systems. Thus, we focus the second part of the review on theoretical aspects of binding, including kinetics, biomechanics, and transport physics. Finally, we discuss various computational and simulation studies of nanoparticle adhesion, including advanced treatments that compare directly to experimental results. Future work will ideally continue to combine experimental data and advanced computational studies to extend our knowledge of multivalent adhesion, as well as design the most powerful nanoparticle-based agents to treat cancer.

Enhanced Cellular Uptake of H-Chain Human Ferritin Containing Gold Nanoparticles

Gold nanoparticles (AuNP) capped with biocompatible layers have functional optical, chemical, and biological properties as theranostic agents in biomedicine. The ferritin protein containing in situ synthesized AuNPs has been successfully used as an effective and completely biocompatible nanocarrier for AuNPs in human cell lines and animal experiments in vivo. Ferritin can be uptaken by different cell types through receptor-mediated endocytosis. Despite these advantages, few efforts have been made to evaluate the toxicity and cellular internalization of AuNP-containing ferritin nanocages. In this work, we study the potential of human heavy-chain (H) and light-chain (L) ferritin homopolymers as nanoreactors to synthesize AuNPs and their cytotoxicity and cellular uptake in different cell lines. The results show very low toxicity of ferritin-encapsulated AuNPs on different human cell lines and demonstrate that efficient cellular ferritin uptake depends on the specific H or L protein chains forming the ferritin protein cage and the presence or absence of metallic cargo. Cargo-devoid apoferritin is poorly internalized in all cell lines, and the highest ferritin uptake was achieved with AuNP-loaded H-ferritin homopolymers in transferrin-receptor-rich cell lines, showing more than seven times more uptake than apoferritin.

Concentration-Independent Multivalent Targeting of Cancer Cells by Genetically Encoded Core-Crosslinked Elastin/Resilin-like Polypeptide Micelles

Valency is a fundamental principle to control macromolecular interactions and is used to target specific cell types by multivalent ligand-receptor interactions using self-assembled nanoparticle carriers. At the concentrations encountered in solid tumors upon systemic administration, these nanoparticles are, however, likely to show critical micelle concentration (CMC)-dependent disassembly and thus loss of function. To overcome this limitation, core-crosslinkable micelles of genetically encoded resilin-/elastin-like diblock polypeptides were recombinantly synthesized. The amphiphilic constructs were covalently photo-crosslinked through the genetically encoded unnatural amino acid para-azidophenylalanine in their hydrophobic block and they carried different anticancer ligands on their hydrophilic block: the wild-type tenth human fibronectin type III domain, a GRGDSPAS peptide-both targeting α_vβ₃ integrin-and an engineered variant of the third fibronectin type III domain of tenascin C that is a death receptor 5 agonist. Although uncrosslinked micelles lost most of their targeting ability below their CMC, the crosslinked analogues remained active at concentrations up to 1000-fold lower than the CMC, with binding affinities that are comparable to antibodies.

Interaction between DNA, Albumin and Apo-Transferrin and Iridium(III) Complexes with Phosphines Derived from Fluoroquinolones as a Potent Anticancer Drug

A group of cytotoxic half-sandwich iridium(III) complexes with aminomethyl(diphenyl)phosphine derived from fluoroquinolone antibiotics exhibit the ability to (i) accumulate in the nucleus, (ii) induce apoptosis, (iii) activate caspase-3/7 activity, (iv) induce the changes in cell cycle leading to G2/M phase arrest, and (v) radicals generation. Herein, to elucidate the cytotoxic effects, we investigated the interaction of these complexes with DNA and serum proteins by gel electrophoresis, fluorescence spectroscopy, circular dichroism, and molecular docking studies. DNA binding experiments established that the complexes interact with DNA by moderate intercalation and predominance of minor groove binding without the capability to cause a double-strand cleavage. The molecular docking study confirmed two binding modes: minor groove binding and threading intercalation with the fluoroquinolone part of the molecule involved in pi stacking interactions and the Ir(III)-containing region positioned within the major or minor groove. Fluorescence spectroscopic data (HSA and apo-Tf titration), together with molecular docking, provided evidence that Ir(III) complexes can bind to the proteins in order to be transferred. All the compounds considered herein were found to bind to the tryptophan residues of HSA within site I (subdomain II A). Furthermore, Ir(III) complexes were found to dock within the apo-Tf binding site, including nearby tyrosine residues.

Targeting nonapoptotic pathways with functionalized nanoparticles for cancer therapy: current and future perspectives

Apoptotic death evasion is a hallmark of cancer progression. In this context, past decades have witnessed cytotoxic agents targeting apoptosis. However, owing to cellular defects in the apoptotic machinery, tumors develop resistance to apoptosis-based cancer therapies. Hence, targeting nonapoptotic cell-death pathways displays enhanced therapeutic success in apoptosis-defective tumor cells. Exploitation of multifunctional properties of engineered nanoparticles may allow cancer therapeutics to target yet unexplored pathways such as ferroptosis, autophagy and necroptosis. Necroptosis presents a programmed necrotic death initiated by same apoptotic death signals that are caspase independent, whereas autophagy is self-degradative causing vacuolation, and ferroptosis is an iron-dependent form driven by lipid peroxidation. Targeting these tightly regulated nonapoptotic pathways may emerge as a new direction in cancer drug development, diagnostics and novel cancer nanotherapeutics. This review highlights the current challenges along with the advancement in this field of research and finally summarizes the future perspective in terms of their clinical merits.

Nanoplatforms for Targeted Stimuli-Responsive Drug Delivery: A Review of Platform Materials and Stimuli-Responsive Release and Targeting Mechanisms

To achieve the promise of stimuli-responsive drug delivery systems for the treatment of cancer, they should (1) avoid premature clearance; (2) accumulate in tumors and undergo endocytosis by cancer cells; and (3) exhibit appropriate stimuli-responsive release of the payload. It is challenging to address all of these requirements simultaneously. However, the numerous proof-of-concept studies addressing one or more of these requirements reported every year have dramatically expanded the toolbox available for the design of drug delivery systems. This review highlights recent advances in the targeting and stimuli-responsiveness of drug delivery systems. It begins with a discussion of nanocarrier types and an overview of the factors influencing nanocarrier biodistribution. On-demand release strategies and their application to each type of nanocarrier are reviewed, including both endogenous and exogenous stimuli. Recent developments in stimuli-responsive targeting strategies are also discussed. The remaining challenges and prospective solutions in the field are discussed throughout the review, which is intended to assist researchers in overcoming interdisciplinary knowledge barriers and increase the speed of development. This review presents a nanocarrier-based drug delivery systems toolbox that enables the application of techniques across platforms and inspires researchers with interdisciplinary information to boost the development of multifunctional therapeutic nanoplatforms for cancer therapy.

Role of vitronectin-rich protein corona on tumor-specific siRNA delivery and transfection with lipid nanoparticles

Aim: To evaluate the role of vitronectin-enriched protein corona on systemic delivery of siRNA-encapsulated cationic lipid nanoparticles (LNPs) to αvβ3 integrin expressing solid tumors. Materials & methods: 1,2-Dioleoyl-3-trimethylammonium-propane LNPs were formulated, protein corona formed in nude mice serum and its impact on drug delivery were analyzed. Results: 1,2-Dioleoyl-3-trimethylammonium-propane-containing LNP led to enhanced recruitment of vitronectin and showed preferential transfection to αvβ3-expressed cells relative to controls. Upon systemic administration in mice, the LNPs accumulated in the αvβ3-expressing endothelial lining of the tumor blood vessels before reaching tumor cells. Conclusion: These results present an optimized LNP that selectively recruits endogenous proteins in situ to its corona which may lead to enhanced delivery and transfection in tissues of interest.

Binding Revisited-Avidity in Cellular Function and Signaling

When characterizing biomolecular interactions, avidity, is an umbrella term used to describe the accumulated strength of multiple specific and unspecific interactions between two or more interaction partners. In contrast to the affinity, which is often sufficient to describe monovalent interactions in solution and where the binding strength can be accurately determined by considering only the relationship between the microscopic association and dissociation rates, the avidity is a phenomenological macroscopic parameter linked to several microscopic events. Avidity also covers potential effects of reduced dimensionality and/or hindered diffusion observed at or near surfaces e.g., at the cell membrane. Avidity is often used to describe the discrepancy or the "extra on top" when cellular interactions display binding that are several orders of magnitude stronger than those estimated in vitro. Here we review the principles and theoretical frameworks governing avidity in biological systems and the methods for predicting and simulating avidity. While the avidity and effects thereof are well-understood for extracellular biomolecular interactions, we present here examples of, and discuss how, avidity and the underlying kinetics influences intracellular signaling processes.

Engineering Mesoporous Silica Nanoparticles for Targeted Alpha Therapy against Breast Cancer

Targeted alpha therapy, where highly cytotoxic doses are delivered to tumor cells while sparing surrounding healthy tissue, has emerged as a promising treatment against cancer. Radionuclide conjugation with targeting vectors and dose confinement, however, are still limiting factors for the widespread application of this therapy. In the current study, we developed multifunctional silica nanoconstructs for targeted alpha therapy that show targeting capabilities against breast cancer cells, cytotoxic responses at therapeutic dosages, and enhanced clearance. The silica nanoparticles were conjugated to transferrin, which promoted particle accumulation in cancerous cells, and 3,4,3-LI(1,2-HOPO), a chelator with high selectivity and binding affinity for f-block elements. High cytotoxic effects were observed when the nanoparticles were loaded with ²²⁵Ac, a clinically relevant radioisotope. Lastly, in vivo studies in mice showed that the administration of radionuclides with nanoparticles enhanced their excretion and minimized their deposition in bones. These results highlight the potential of multifunctional silica nanoparticles as delivery systems for targeted alpha therapy and offer insight into design rules for the development of new nanotherapeutic agents.

Combined Tumor Environment Triggered Self-Assembling Peptide Nanofibers and Inducible Multivalent Ligand Display for Cancer Cell Targeting with Enhanced Sensitivity and Specificity

Many new technologies, such as cancer microenvironment-induced nanoparticle targeting and multivalent ligand approach for cell surface receptors, are developed for active targeting in cancer therapy. While the principle of each technology is well illustrated, most systems suffer from low targeting specificity and sensitivity. To fill the gap, this work demonstrates a successful attempt to combine both technologies to simultaneously improve cancer cell targeting sensitivity and specificity. Specifically, the main component is a targeting ligand conjugated self-assembling monomer precursor (SAM-P), which, at the tumor site, undergoes tumor-triggered cleavage to release the active form of self-assembling monomer capable of forming supramolecular nanostructures. Biophysical characterization confirms the chemical and physical transformation of SAM-P from unimers or oligomers with low ligand valency to supramolecular assemblies with high ligand valency under a tumor-mimicking reductive microenvironment. The in vitro fluorescence assay shows the importance of supramolecular morphology in mediating ligand-receptor interactions and targeting sensitivity. Enhanced targeting specificity and sensitivity can be achieved via tumor-triggered supramolecular assembly and induces multivalent ligand presentation toward cell surface receptors, respectively. The results support this combined tumor microenvironment-induced cell targeting and multivalent ligand display approach, and have great potential for use as cell-specific molecular imaging and therapeutic agents with high sensitivity and specificity.

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.

Application of advances in endocytosis and membrane trafficking to drug delivery

Multidisciplinary research efforts in the field of drug delivery have led to the development of a variety of drug delivery systems (DDS) designed for site-specific delivery of diagnostic and therapeutic agents. Since efficient uptake of drug carriers into target cells is central to effective drug delivery, a comprehensive understanding of the biological pathways for cellular internalization of DDS can facilitate the development of DDS capable of precise tissue targeting and enhanced therapeutic outcomes. Diverse methods have been applied to study the internalization mechanisms responsible for endocytotic uptake of extracellular materials, which are also the principal pathways exploited by many DDS. Chemical inhibitors remain the most commonly used method to explore endocytotic internalization mechanisms, although genetic methods are increasingly accessible and may constitute more specific approaches. This review highlights the molecular basis of internalization pathways most relevant to internalization of DDS, and the principal methods used to study each route. This review also showcases examples of DDS that are internalized by each route, and reviews the general effects of biophysical properties of DDS on the internalization efficiency. Finally, options for intracellular trafficking and targeting of internalized DDS are briefly reviewed, representing an additional opportunity for multi-level targeting to achieve further specificity and therapeutic efficacy.

Programmed Self-Assembly of Protein-Coated AIE-Featured Nanoparticles with Dual Imaging and Targeted Therapy to Cancer Cells

Modifying different functional moieties into one platform is a conventional strategy for constructing theranostic systems. However, this strategy usually suffers from the unsatisfied efficiency of each individual function. Herein, a programmed self-assembly strategy is presented to fabricate theranostic nanoparticles, which significantly exhibit a dual-modality imaging function involving fluorescence imaging and magnetic resource imaging (MRI), and an efficient targeted therapy to cancer cells. Fluorescent vesicles are first self-assembled by aggregation-induced emission (AIE)-active molecules. Gd³⁺, serving as an MRI agent, is subsequently bound to the vesicles to provide highly positive charges, which have been realized to be anticancer active. Thereafter, transferrin (Tf) protein is introduced onto the surface of Gd³⁺ coordinated vesicles, shielding the positive charges and making the nanoparticles nontoxic to cells. With the assistance of Tf protein, the constructed nanoparticles are specifically targeted to cancer cells. Moreover, Tf proteins further peel off from nanoparticles in lysosomes due to their charge reversion, resulting in highly positive charges and heavy toxicity of nanoparticles to kill cancer cells. In the nanoparticles, each of the functional components acts as double-sided adhesive tape to glue the next layer, so that the abilities of functional components are not compromised. This strategy holds great potential for theranostic nanomedicine.

Hierarchically targetable fiber rods decorated with dual targeting ligands and detachable zwitterionic coronas

The shapes of drug carriers have significant effects on the drug's blood circulation lifetime and tumor accumulation levels. In this study, nonspherical drug carriers of fiber rods are enhanced with hierarchically targeting capabilities to achieve long circulation in blood, on-demand recovery of cell targeting ligands in tumor tissues and dual ligands-mediated cellular uptake. Zwitterionic polymers are conjugated on fiber rods via acid-labile linkers as stealth coronas to reduce the capture by macrophages and shield the targeting ligands. Compared with commonly used poly(ethylene glycol), the zwitterionic grafts show significantly higher inhibition of protein adsorption and lower internalization by macrophages, leading to around 2 folds longer blood circulation and over 2.5 folds higher drug accumulation in tumors than pristine fiber rods. To address the conflicts between blood circulation and cellular uptake, the zwitterionic coronas are efficiently removed in the slightly acidic tumor microenvironment. The exposure of targeting ligands could activate the internalization by tumor cells, resulting in higher cytotoxicity and tumor accumulation than those with stable linkers. Fiber rods are grafted with dual ligands of folate and biotin, and the optimal ligand densities and ratios are determined to maximize the tumor cell uptake. Compared with other treatment, fiber rods with decorated zwitterionic coronas and acid-liable exposure of dual targeting ligands enhance the suppression of tumor growth, prolong animal survival, and cause less lung metastasis. The development of fiber rods with hierarchically targeting capabilities shows great potential in improving the blood circulation, tumor accumulation and cellular uptake, and eventually promoting therapeutic efficacy. STATEMENT OF SIGNIFICANCE: The targeted delivery of chemotherapeutic agents will encounter a series of biological and pathological barriers. In this study, fiber rods were empowered with hierarchically targeting capabilities to resolve the conflict between blood circulation and cellular uptake. This strategy has shown several advantages over the existing methods. Firstly, zwitterionic polymers were used as blood circulation ligands, and concrete evidence was provided via head-to-head comparison with commonly used poly(ethylene glycol) ligands in the macrophage uptake and in vivo tissue distribution. Secondly, the depletion of circulation ligands and on-demand exposure of targeting ligands in tumor tissues showed crucial effects on the uptake by tumor cells. Thirdly, the densities and ratios of the dual targeting ligands were initially determined for a maximal cellular internalization.

Molecular insights and novel approaches for targeting tumor metastasis

In recent years, due to the effective drug delivery and preciseness of tumor sites or microenvironment, the targeted drug delivery approaches have gained ample attention for tumor metastasis therapy. The conventional treatment approaches for metastasis therapy have reported with immense adverse effects because they exhibited maximum probability of killing the carcinogenic cells along with healthy cells. The tumor vasculature, comprising of vasculogenic impressions and angiogenesis, greatly depends upon the growth and metastasis in the tumors. Therefore, various nanocarriers-based delivery approaches for targeting to tumor vasculature have been attempted as efficient and potential approaches for the treatment of tumor metastasis and the associated lesions. Furthermore, the targeted drug delivery approaches have found to be most apt way to overcome from all the limitations and adverse effects associated with the conventional therapies. In this review, various approaches for efficient targeting of pharmacologically active chemotherapeutics against tumor metastasis with the cohesive objectives of prognosis, tracking and therapy are summarized.

Quality by design (QbD) approach in processing polymeric nanoparticles loading anticancer drugs by high pressure homogenizer

Polymeric nanoparticles prepared using high pressure homogenizer (HPH) present some unique challenges during manufacturing which can be better understood by application of quality by design (QbD) approaches. The present review highlights the ways to identify the critical material attributes which includes the anticancer drugs, polymers, surfactants, solvent system and dispersion system. A comprehensive understanding of the critical processing parameters like pressure and number of cycles during the working of HPH used in putting forward the critical quality attributes such as size, shape, surface charge or droplet stabilization. Such QbD approach will involve development of an effective control strategy for would ensure safe encapsulation of anticancer drugs for successful product development. Proper addressing of the issues related to scaling-up would lead to successful commercialization of the nano-sized formulations loaded with anticancer drugs.

Copper chalcogenide materials as photothermal agents for cancer treatment

Copper-based chalcogenide nanomaterials have made tremendous progress for cancer theranostics due to their simple preparation, low cost, stable performance, and easy functionalization. But a systematic review and analysis about them does not exist. Therefore, we offer an account, mainly focusing on the design and functionalization of the copper-based chalcogenide nanomaterials for cancer theranostics, aiming to briefly demonstrate the design and concepts, summarize some of the past studies and analyze the development trends in the copper-based chalcogenide nanomaterials for clinical application.

Targeting cancer cells with nanotherapeutics and nanodiagnostics: Current status and future perspectives

Nanotechnology is reshaping health care strategies and is expected to exert a tremendous impact in the coming years offering better healthcare facilities. It has led to not only therapeutic drug delivery feasibility but also to diagnostics. Materials in the size of nano range (1-100 nm) used in the design, fabrication, regulation, and application of therapeutic drugs or devices are classified as medical nanotechnology and nanopharmacology. Delivery of more complex molecules to the specific site of action as well as gene therapy has pushed forward the nanoparticle-based drug delivery to its maximum. Areas that benefit from nano-based drug delivery systems are cancer, diabetes, infectious diseases, neurodegenerative diseases, blood disorders and orthopedic-related ailments. Moreover, development of nanotherapeutics with multi-functionalities has a considerable potential to fill the gaps that exist in the present therapeutic domain. In cancer treatment, nanomedicines have superiority over current therapeutic practices as they can effectively deliver the drug to the affected tissues, thus reducing drug toxicities. Along this line, polymeric conjugates of asparaginase and polymeric micelles of paclitaxel have recently been recommended for the treatment of various types of cancers. Nanotechnology-based therapeutics and diagnostics provide greater effectiveness with less or no toxicity concerns. Similarly, diagnostic imaging holds promising future applications with newer nano-level imaging elements. Advancements in nanotechnology have emerged to a newer direction which use nanorobotics for various applications in healthcare. Accordingly, this review comprehensively highlights the potentialities of various nanocarriers and nanomedicines for multifaceted applications in diagnostics and drug delivery, especially the potentialities of polymeric nanoparticle, nanoemulsion, solid-lipid nanoparticle, nanostructured lipid carrier, self-micellizing anticancer lipids, dendrimer, nanocapsule and nanosponge-based therapeutic approaches in the field of cancer. Furthermore, this article summarizes the most recent literature pertaining to the use of nano-technology in the field of medicine, particularly in treating cancer patients.