Design of biocompatible dendrimers for cancer diagnosis and therapy: current status and future perspectives

Magnetic targeting and pH-microwave dual responsive Janus mesoporous silica nanoparticles for drug encapsulation and delivery

In this paper, a new Janus-structured nano drug delivery carrier Fe3O4@TiO2&mSiO2was designed and synthesized, which consisted of a spherical head and a closely connected rod. The head was a nanocomposite of core/shell structure with magnetic spinel ferric tetraoxide core and anatase titanium dioxide shell (Fe3O4@TiO2), and the rod was ordered mesoporous silica (mSiO2). The nanocarriers showed excellent magnetic targeting capability (saturation magnetization, 25.18 emu g-1). The core/shell heads endowed the carriers with fine microwave responsiveness. The pore volume of mesoporous nanocarriers was 0.101 cm3g-1, and the specific surface area was 489.0 m2g-1. Anticancer drug doxorubicin could be loaded in the mesoporous of the carriers to form Fe3O4@TiO2&mSiO2-DOX. The drug loading capacity was 10.4%. Fe3O4@TiO2&mSiO2-DOX exhibited acid-sensitive and microwave-sensitive release properties along with good bio-compatibility. Fe3O4@TiO2&mSiO2Janus nanoparticles are expected to be ideal drug carriers.

Dendritic Pyridine-Imine Copper Complexes as Metallo-Drugs

Since the discovery of cisplatin in the 1960s, the search for metallo-drugs that are more efficient than platinum complexes with negligible side effects has attracted much interest. Among the other metals that have been examined for potential applications as anticancer agents is copper. The interest in copper was recently boosted by the discovery of cuproptosis, a recently evidenced form of cell death mediated by copper. However, copper is also known to induce the proliferation of cancer cells. In view of these contradictory results, there is a need to find the most suitable copper chelators, among which Schiff-based derivatives offer a wide range of possibilities. Gathering several metal complexes in a single, larger entity may provide enhanced properties. Among the nanometric objects suitable for such purpose are dendrimers, precisely engineered hyperbranched macromolecules, which are outstanding candidates for improving therapy and diagnosis. In this review article, we present an overview of the use of a particular Schiff base, namely pyridine-imine, linked to the surface of dendrimers, suitable for complexing copper, and the use of such dendrimer complexes in biology, in particular against cancers.

Multiple Immunomodulatory Strategies Based on Targeted Regulation of Proprotein Convertase Subtilisin/Kexin Type 9 and Immune Homeostasis against Hepatocellular Carcinoma

Immunotherapy is the most promising systemic therapy for hepatocellular carcinoma. However, the outcome remains poor. Proprotein convertase subtilisin/kexin type 9 (PCSK9) plays a role in altering cell-surface protein levels, potentially undermining the efficacy of immunotherapy against tumors. This highlights its potential as a target for antitumor therapy. Herein, CaCO3-based nanoparticles coencapsulated with DOX, an immunogenic cell death (ICD) inducer, and evolocumab was developed to enhanced the efficacy of immunotherapy. The obtained DOX/evolocumab-loaded CaCO3 nanoparticle (named DECP) exhibits a good capacity of acid neutralization and causes ICD of cancer cells. In addition, DECP is able to evaluate the cell-surface level of MHC-I, a biomarker that correlates positively with patients' overall survival. Upon intravenous injection, DECP accumulates within the tumor site, leading to growth inhibition of hepa1-6 bearing subcutaneous tumors. Specifically, DECP treatment causes augmented ratios of matured dendritic cells, tumor-infiltrating CD8+ T cells and natural killing cells, while concurrently depleting Foxp3+ regulatory T cells. Peritumoral delivery of DECP enhances the immune response of distant tumors and exhibits antitumor effects when combined with intravenous αPD-L1 therapy in a bilateral tumor model. This study presents CaCO3-based nanoparticles with multiple immunomodulatory strategies against hepatocellular carcinoma by targeting PCSK9 inhibition and modulating immune homeostasis in the unfavorable TME.

How the Length of Through-Space Conjugation Influences the Clusteroluminescence of Oligo(Phenylene Methylene)s

The length and mode of conjugation directly affect the molecular electronic structure, which has been extensively studied in through-bond conjugation (TBC) systems. Corresponding research greatly promotes the development of TBC-based luminophores. However, how the length and mode of through-space conjugation (TSC), one kind of weak interaction, influence the photophysical properties of non-conjugated luminophores remains a relatively unexplored field. Here, we unveil a non-linear relationship between TSC length and emission characteristics in non-conjugated systems, in contrast to the reported proportional correlation in TBC systems. More specifically, oligo(phenylene methylene)s (OPM[4]-OPM[7]) exhibit stronger TSC and prominent blue clusteroluminescence (CL) (≈440 nm) compared to shorter counterparts (OPM[2] and OPM[3]). OPM[6] demonstrates the highest solid-state quantum yield (40 %), emphasizing the importance of balancing flexibility and rigidity. Further theoretical calculations confirmed that CL of these oligo(phenylene methylene)s was determined by stable TSC derived from the inner rigid Diphenylmethane (DPM) segments within the oligomers instead of the outer ones. This discovery challenges previous assumptions and adds a new dimension to the understanding of TSC-based luminophores in non-conjugated systems.

Stimuli-Responsive Nanoradiosensitizers for Enhanced Cancer Radiotherapy

Radiotherapy (RT) has been a classical therapeutic method of cancer for several decades. It attracts tremendous attention for the precise and efficient treatment of local tumors with stimuli-responsive nanomaterials, which enhance RT. However, there are few systematic reviews summarizing the newly emerging stimuli-responsive mechanisms and strategies used for tumor radio-sensitization. Hence, this review provides a comprehensive overview of recently reported studies on stimuli-responsive nanomaterials for radio-sensitization. It includes four different approaches for sensitized RT, namely endogenous response, exogenous response, dual stimuli-response, and multi stimuli-response. Endogenous response involves various stimuli such as pH, hypoxia, GSH, and reactive oxygen species (ROS), and enzymes. On the other hand, exogenous response encompasses X-ray, light, and ultrasound. Dual stimuli-response combines pH/enzyme, pH/ultrasound, and ROS/light. Lastly, multi stimuli-response involves the combination of pH/ROS/GSH and X-ray/ROS/GSH. By elaborating on these responsive mechanisms and applying them to clinical RT diagnosis and treatment, these methods can enhance radiosensitive efficiency and minimize damage to surrounding normal tissues. Finally, this review discusses the additional challenges and perspectives related to stimuli-responsive nanomaterials for tumor radio-sensitization.

Dual anticancer and antibacterial activity of fluorescent naphthoimidazolium salts

Cancer has emerged as a significant global health challenge, ranking as the second leading cause of death worldwide. Moreover, cancer patients frequently experience compromised immune systems, rendering them susceptible to bacterial infections. Combining anticancer and antibacterial properties in a single drug could lead to improved overall treatment outcomes and patient well-being. In this context, the present study focused on a series of hydrophilic naphthoimidazolium salts with donor groups (NI-R), aiming to create dual-functional agents with antibacterial and anticancer activities. Among these compounds, NI-TPA demonstrated notable antibacterial activity, particularly against drug-resistant bacteria, with MIC value of 7.8 μg mL-1. Furthermore, NI-TPA exhibited the most potent cytotoxicity against four different cancer cell lines, with an IC50 range of 0.67-2.01 μg mL-1. The observed high cytotoxicity of NI-TPA agreed with molecular docking and dynamic simulation studies targeting c-Met kinase protein. Additionally, NI-TPA stood out as the most promising candidate for two-photo excitation, fluorescence bioimaging, and localization in lysosomes. The study findings open new avenues for the design and development of imidazolium salts that could be employed in phototheranostic applications for cancer treatment and bacterial infections.

Nanoreactor-based catalytic systems for therapeutic applications: Principles, strategies, and challenges

Inspired by natural catalytic compartments, various synthetic compartments that seclude catalytic reactions have been developed to understand complex multistep biosynthetic pathways, bestow therapeutic effects, or extend biosynthetic pathways in living cells. These emerging nanoreactors possessed many advantages over conventional biomedicine, such as good catalytic activity, specificity, and sustainability. In the past decade, a great number of efficient catalytic systems based on diverse nanoreactors (polymer vesicles, liposome, polymer micelles, inorganic-organic hybrid materials, MOFs, etc.) have been designed and employed to initiate in situ catalyzed chemical reactions for therapy. This review aims to present the recent progress in the development of catalytic systems based on nanoreactors for therapeutic applications, with a special emphasis on the principles and design strategies. Besides, the key components of nanoreactor-based catalytic systems, including nanocarriers, triggers or energy inputs, and products, are respectively introduced and discussed in detail. Challenges and prospects in the fabrication of therapeutic catalytic nanoreactors are also discussed as a conclusion to this review. We believe that catalytic nanoreactors will play an increasingly important role in modern biomedicine, with improved therapeutic performance and minimal side effects.

Precise delivery of celastrol by PEGylated aptamer dendrimer nanoconjugates for enormous therapeutic effect via superior intratumor penetration over antibody counterparts

Antibody-coated nanoparticles have been reported to have the extremely low delivery efficiency in solid tumors in preclinical trials. Though aptamers were considered to be superior over antibodies in cancer theranostics, whether PEGylated aptamer nanoparticles are better than antibody nanoparticles in improving delivery specificity and penetration efficiency of chemotherapeutics is still unknown. Here, we conjugate celastrol, a natural product with anti-tumor effect, onto PEGylated EpCAM aptamer or antibody dendrimers to obtain two nanoconjugates, and for the first time, conduct a comprehensive study to compare their performance in delivery specificity, intratumoral penetration ability and therapeutic outcomes. Our results showed that compared to antibody counterparts, PEGylated aptamer nanoconjugates exhibited the enhanced accumulation and retention specificities at tumor sites and the stronger intratumoral penetration capabilities by reducing the macrophage reservoir effects in solid tumors. When delivered celastrol to a colorectal xenograft tumor mice model by PEGylated aptamer dendrimers, 20 % of enhanced therapeutic efficiency was achieved compared to that by antibody-modified ones. Moreover, celastrol at 2 mg/kg delivered by PEGylated aptamer dendrimers showed the prominent anticancer efficiency (nearly 92 %) but without obvious side effects. These data firstly provide the proof-of-concept implementation that PEGylated aptamer nanoconjugates will display the great potential in the effective and safe cancer treatment with regard to the superiority over antibody ones in penetration abilities.

Nuclear Delivery of Nanoparticle-Based Drug Delivery Systems by Nuclear Localization Signals

Nanomedicine 2.0 refers to the next generation of nanotechnology-based medical therapies and diagnostic tools. This field focuses on the development of more sophisticated and precise nanoparticles (NPs) for targeted drug delivery, imaging, and sensing. It has been established that the nuclear delivery of NP-loaded drugs can increase their therapeutic efficacy. To effectively direct the NPs to the nucleus, the attachment of nuclear localization signals (NLSs) to NPs has been employed in many applications. In this review, we will provide an overview of the structure of nuclear pore complexes (NPCs) and the classic nuclear import mechanism. Additionally, we will explore various nanoparticles, including their synthesis, functionalization, drug loading and release mechanisms, nuclear targeting strategies, and potential applications. Finally, we will highlight the challenges associated with developing nucleus-targeted nanoparticle-based drug delivery systems (NDDSs) and provide insights into the future of NDDSs.

Nanoparticle-Mediated Radiotherapy Remodels the Tumor Microenvironment to Enhance Antitumor Efficacy

Radiotherapy (RT) uses ionizing radiation to eradicate localized tumors and, in rare cases, control tumors outside of the irradiated fields via stimulating an antitumor immune response (abscopal effect). However, the therapeutic effect of RT is often limited by inherent physiological barriers of the tumor microenvironment (TME), such as hypoxia, abnormal vasculature, dense extracellular matrix (ECM), and an immunosuppressive TME. Thus, it is critical to develop new RT strategies that can remodel the TME to overcome radio-resistance and immune suppression. In the past decade, high-Z-element nanoparticles have been developed to increase radiotherapeutic indices of localized tumors by reducing X-ray doses and side effects to normal tissues and enhance abscopal effects by activating the TME to elicit systemic antitumor immunity. In this review, the principles of RT and radiosensitization, the mechanisms of radio-resistance and immune suppression, and the use of various nanoparticles to sensitize RT and remodel TMEs for enhanced antitumor efficacy are discussed. The challenges in clinical translation of multifunctional TME-remodeling nanoradiosensitizers are also highlighted.

Multifunctional Dendritic Au@SPP@DOX Nanoparticles Integrating Chemotherapy and Low-Dose Radiotherapy for Enhanced Anticancer Activity

Combined chemoradiotherapy can improve antitumor efficiency and reduce the side effects of monotherapy. In this study, we aimed to construct dendritic peptide-based multifunctional nanoparticles (Au@SPP@DOX) for a prolonged circulation time, enhanced cellular uptake, and targeted cancer therapy. Amphiphilic micelle PEG-polylysine-SA (SPP) is composed of polylysine combined with hydrophilic poly(ethylene glycol) (PEG) and hydrophobic stearic acid (SA). Doxorubicin (DOX) is loaded via the hydrophilic-hydrophobic interaction of SPP, and gold nanoparticles (AuNPs) are loaded via the electrostatic interaction with SPP. Au@SPP@DOX showed good biocompatibility and could be successfully accumulated at tumor sites through the enhanced permeability and retention (EPR) effect. Then, lysosomes could be ruptured due to the proton sponge effect. DOX became protonated in response to tumor extracellular acidity and was then released from SPP. Under the action of low-dose radiation, Au@SPP@DOX could promote the production of reactive oxygen species (ROS), increase mitochondrial dysfunction, block cell division, and ultimately promote tumor cell apoptosis to achieve a better antitumor effect. This study highlighted the benefit of chemoradiotherapy and suggested that Au@SPP@DOX might serve as a high-efficiency codelivery system for cancer combination therapy in the future.

Recent Advances in Oral and Transdermal Protein Delivery Systems

Protein and peptide drugs are predominantly administered by injection to achieve high bioavailability, but this greatly compromises patient compliance. Oral and transdermal drug delivery with minimal invasiveness and high adherence represent attractive alternatives to injection administration. However, oral and transdermal administration of bioactive proteins must overcome biological barriers, namely the gastrointestinal and skin barriers, respectively. The rapid development of new materials and technologies promises to address these physiological obstacles. This review provides an overview of the latest advances in oral and transdermal protein delivery, including chemical strategies, synthetic nanoparticles, medical microdevices, and biomimetic systems for oral administration, as well as chemical enhancers, physical approaches, and microneedles in transdermal delivery. We also discuss challenges and future perspectives of the field with a focus on innovation and translation.

Preparation and characterization of cationic hyperbranched maltodextrins as potential carrier for siRNA encapsulation

The present study sought to investigate the physicochemical properties of cationic branched maltodextrins with similar degrees of substitution but different degrees of branching and their siRNA delivery capacity. The results showed that the ratio of α-1,6 glycosidic bonds was significantly increased in the sample treated with dual enzymes. The structural characterization results showed that abundant short chains reassembled by 1,4-α-glucan branching enzyme (GBEs) hydrolysis formed hyperbranched short clustered structure. The absorption peaks that appeared in the FT-IR spectrum confirmed the occurrence of quaternization. The complexes formed by self-assembly of cationic maltodextrins and siRNA were verified by the gel retardation assay and atomic force microscopy, demonstrating a uniform spherical structure with a size close to 300-350 nm. Meanwhile, cationic branched maltodextrins could effectively reduce the change of secondary structure of siRNA. Overall, the results suggested that branched maltodextrins with a cationic surface had significant potential as siRNA carriers.

Facially Amphiphilic Skeleton-Derived Antibacterial Cationic Dendrimers

It is urgent to develop biocompatible and high-efficiency antimicrobial agents since microbial infections have always posed serious challenges to human health. Herein, through the marriage of facially amphiphilic skeletons and cationic dendrimers, high-density positively charged dendrimers D-CA₆-N⁺ (G2) and D-CA₂-N⁺ (G1) were designed and synthesized using the "branch" of facially amphiphilic bile acids, followed by their modification with quaternary ammonium charges. Both dendrimers could self-assemble into nanostructured micelles in aqueous solution. D-CA₆-N⁺ displays potent antibacterial activity against Staphylococcus aureus and Escherichia coli, with minimum inhibitory concentrations (MICs) as low as 7.50 and 7.79 μM, respectively, and has an evidently stronger antibacterial activity than D-CA₂-N⁺. Moreover, D-CA₆-N⁺ can kill S. aureus faster than E. coli. The facial amphiphilicity of the bile acid skeleton facilitates the selective destruction of bacterial membranes and endows dendrimers with negligible hemolysis and cytotoxicity even under a high concentration of 16× MIC. In vivo studies show that D-CA₆-N⁺ is much more effective and safer than penicillin G in treating S. aureus infection and promoting wound healing, which suggests facially amphiphilic skeleton-derived cationic dendrimers can be a promising approach to effectively enhance antibacterial activity and biocompatibility of antibacterial agent, simultaneously.

Poloxam Thermosensitive Hydrogels Loaded with hFGF2-Linked Camelina Lipid Droplets Accelerate Skin Regeneration in Deep Second-Degree Burns

Burn injuries are difficult to manage due to the defect of large skin tissues, leading to major disability or even death. Human fibroblast growth factor 2 (hFGF2) is known to promote burn wound healing. However, direct administration of hFGF2 to the wound area would affect the bioactivity. To provide a supportive environment for hFGF2 and control its release in a steady fashion, in this research, we developed novel thermosensitive poloxam hydrogels delivered with hFGF2-linked Camelina lipid droplets (CLD-hFGF2 hydrogels). Cryopreserved scanning electron microscopy (SEM) results indicated that the incorporation of CLD-hFGF2 does not significantly affect the inner structure of hydrogels. The rheological properties showed that CLD-hFGF2 hydrogels gelated in response to temperature, thus optimizing the delivery method. In vitro, CLD-hFGF2 could be released from hydrogels for 3 days after drug delivery (the release rate was 72%), and the release solution could still promote the proliferation and migration of NIH3T3 cells. In vivo, compared with hydrogels alone or with direct CLD-hFGF2 administration, CLD-hFGF2 hydrogels had the most obvious effect on deep second-degree burn wound healing. This work indicates that CLD-hFGF2 hydrogels have potential application value in burn wound healing.

Stimuli-responsive platinum and ruthenium complexes for lung cancer therapy

Lung cancer is the most common cause of cancer-related deaths worldwide. More efficient treatments are desperately needed. For decades, the success of platinum-based anticancer drugs has promoted the exploration of metal-based agents. Four ruthenium-based complexes have also entered clinical trials as candidates of anticancer metallodrugs. However, systemic toxicity, severe side effects and drug-resistance impeded their applications and efficacy. Stimuli-responsiveness of Pt- and Ru-based complexes provide a great chance to weaken the side effects and strengthen the clinical efficacy in drug design. This review provides an overview on the stimuli-responsive Pt- and Ru-based metallic anticancer drugs for lung cancer. They are categorized as endo-stimuli-responsive, exo-stimuli-responsive, and dual-stimuli-responsive prodrugs based on the nature of stimuli. We describe various representative examples of structure, response mechanism, and potential medical applications in lung cancer. In the end, we discuss the future opportunities and challenges in this field.

Surface Engineered Dendrimers: A Potential Nanocarrier for the Effective Management of Glioblastoma Multiforme

Gliomas are the most prevailing intracranial tumors, which account for approximately 36% of the primary brain tumors of glial cells. Glioblastoma multiforme (GBM) possesses a higher degree of malignancy among different gliomas. The blood-brain barrier (BBB) protects the brain against infections and toxic substances by preventing foreign molecules or unwanted cells from entering the brain parenchyma. Nano-carriers such as liposomes, nanoparticles, dendrimers, etc. boost the brain permeability of various anticancer drugs or other drugs. The favorable properties like small size, better solubility, and the modifiable surface of dendrimers have proven their broad applicability in the better management of GBM. However, in vitro and in vivo toxicities caused by dendrimers have been a significant concern. The presence of multiple functionalities on the surface of dendrimers enables the grafting of target ligand and/or therapeutic moieties. Surface engineering improves certain properties like targeting efficiency, pharmacokinetic profile, therapeutic effect, and toxicity reduction. This review will be focused on the role of different surface-modified dendrimers in the effective management of GBM.

Secondary through-space interactions facilitated single-molecule white-light emission from clusteroluminogens

Clusteroluminogens refer to some non-conjugated molecules that show visible light and unique electronic properties with through-space interactions due to the formation of aggregates. Although mature and systematic theories of molecular photophysics have been developed to study conventional conjugated chromophores, it is still challenging to endow clusteroluminogens with designed photophysical properties by manipulating through-space interactions. Herein, three clusteroluminogens with non-conjugated donor-acceptor structures and different halide substituents are designed and synthesized. These compounds show multiple emissions and even single-molecule white-light emission in the crystalline state. The intensity ratio of these emissions is easily manipulated by changing the halide atom and excitation wavelength. Experimental and theoretical results successfully disclose the electronic nature of these multiple emissions: through-space conjugation for short-wavelength fluorescence, through-space charge transfer based on secondary through-space interactions for long-wavelength fluorescence, and room-temperature phosphorescence. The introduction of secondary through-space interactions to clusteroluminogens not only enriches their varieties of photophysical properties but also inspires the establishment of novel aggregate photophysics for clusteroluminescence.

Although mature and systematic theories of molecular photophysics have been developed, it is still challenging to endow clusteroluminogens (CLgens) with designed photophysical properties by manipulating through-space interactions. Here, the authors design three CLgens that show multiple emissions and white-light emission in the crystalline state, and emphasize the important role of secondary through-space interactions between the acceptor and non-conjugated donor units.

Safety Challenges and Application Strategies for the Use of Dendrimers in Medicine

Dendrimers are used for a variety of applications in medicine but, due to their host–guest and entrapment characteristics, are particularly used for the delivery of genes and drugs. However, dendrimers are intrinsically toxic, thus creating a major limitation for their use in biological systems. To reduce such toxicity, biocompatible dendrimers have been designed and synthesized, and surface engineering has been used to create advantageous changes at the periphery of dendrimers. Although dendrimers have been reviewed previously in the literature, there has yet to be a systematic and comprehensive review of the harmful effects of dendrimers. In this review, we describe the routes of dendrimer exposure and their distribution in vivo. Then, we discuss the toxicity of dendrimers at the organ, cellular, and sub-cellular levels. In this review, we also describe how technology can be used to reduce dendrimer toxicity, by changing their size and surface functionalization, how dendrimers can be combined with other materials to generate a composite formulation, and how dendrimers can be used for the diagnosis of disease. Finally, we discuss future challenges, developments, and research directions in developing biocompatible and safe dendrimers for medical purposes.

Dendrimers as nanoscale vectors: Unlocking the bars of cancer therapy

Chemotherapy is the first choice in the treatment of cancer and is always preferred to other approaches such as radiation and surgery, but it has never met the need of patients for a safe and effective drug. Therefore, new advances in cancer treatment are now needed to reduce the side effects and burdens associated with chemotherapy for cancer patients. Targeted treatment using nanotechnology are now being actively explored as they could effectively deliver therapeutic agents to tumor cells without affecting normal cells. Dendrimers are promising nanocarriers with distinct physiochemical properties that have received considerable attention in cancer therapy studies, which is partly due to the numerous functional groups on their surface. In this review, we discuss the progress of different types of dendrimers as delivery systems in cancer therapy, focusing on the challenges, opportunities, and functionalities of the polymeric molecules. The paper also reviews the various role of dendrimers in their entry into cells via endocytosis, as well as the molecular and inflammatory pathways in cancer. In addition, various dendrimers-based drug delivery (e.g., pH-responsive, enzyme-responsive, redox-responsive, thermo-responsive, etc.) and lipid-, amino acid-, polymer- and nanoparticle-based modifications for gene delivery, as well as co-delivery of drugs and genes in cancer therapy with dendrimers, are presented. Finally, biosafety concerns and issues hindering the transition of dendrimers from research to the clinic are discussed to shed light on their clinical applications.

Functionalization of Nanoparticulate Drug Delivery Systems and Its Influence in Cancer Therapy

Research into the application of nanocarriers in the delivery of cancer-fighting drugs has been a promising research area for decades. On the other hand, their cytotoxic effects on cells, low uptake efficiency, and therapeutic resistance have limited their therapeutic use. However, the urgency of pressing healthcare needs has resulted in the functionalization of nanoparticles' (NPs) physicochemical properties to improve clinical outcomes of new, old, and repurposed drugs. This article reviews recent research on methods for targeting functionalized nanoparticles to the tumor microenvironment (TME). Additionally, the use of relevant engineering techniques for surface functionalization of nanocarriers (liposomes, dendrimers, and mesoporous silica) and their critical roles in overcoming the current limitations in cancer therapy-targeting ligands used for targeted delivery, stimuli strategies, and multifunctional nanoparticles-were all reviewed. The limitations and future perspectives of functionalized nanoparticles were also finally discussed. Using relevant keywords, published scientific literature from all credible sources was retrieved. A quick search of the literature yielded almost 400 publications. The subject matter of this review was addressed adequately using an inclusion/exclusion criterion. The content of this review provides a reasonable basis for further studies to fully exploit the potential of these nanoparticles in cancer therapy.

Nanomaterials Based on Functional Polymers for Sensitizing Cancer Radiotherapy

Despite being the mainstay treatment for many types of cancer in clinic, radiotherapy is undertaking great challenges in overcoming a series of limitations. Radiosensitizers are promising agents capable of depositing irradiation energy and generating free radicals to enhance the radiosensitivity of tumor cells. Combining radiosensitizers with functional polymer-based nanomaterials holds great potential to improve biodistribution, circulation time, and stability in vivo. The derived polymeric nano-radiosensitizers can significantly improve the efficiency of tumor targeting and radiotherapy, and reduce the side effect to healthy tissues. In this review, we provide an overview of functional polymer-based nanomaterials for radiosensitization in recent years. Particular emphases are given to the action mechanisms, drug loading methods, targeting efficiencies, the impact on therapeutic effects and biocompatibility of various radiosensitizing polymers, which are classified as polymeric micelles, dendrimers, polymeric nanospheres, nanoscale coordination polymers, polymersomes, and nanogels. The challenges and outlooks of polymeric nano-radiosensitizers are also discussed. This article is protected by copyright. All rights reserved.

Nanomaterials: The New Antimicrobial Magic Bullet

Bacterial infections are a significant cause of mortality and morbidity worldwide, despite decades of use of numerous existing antibiotics and constant efforts by researchers to discover new antibiotics. The emergence of infections associated with antibiotic-resistant bacterial strains, has amplified the pressure to develop additional bactericidal therapies or new unorthodox approaches that can deal with antimicrobial resistance. Nanomaterial-based strategies, particularly those that do not rely on conventional small-molecule antibiotics, offer promise in part due to their ability to dodge existing mechanisms used by drug-resistant bacteria. Therefore, the use of nanomaterial-based formulations has attracted attention in the field of antibiotic therapy. In this Review, we highlight novel and emerging nanomaterial-based formulations along with details about the mechanisms by which nanoparticles can target bacterial infections and antimicrobial resistance. A detailed discussion about types and the activities of nanoparticles is presented, along with how they can be used as either delivery systems or as inherent antimicrobials, or a combination of both. Lastly, we highlight some toxicological concerns for the use of nanoparticles in antibiotic therapies.

Genetic Engineering of Dendritic Cells Using Partially Zwitterionic Dendrimer-Entrapped Gold Nanoparticles Boosts Efficient Tumor Immunotherapy

Effective processing and cross-priming of tumor neoantigen by dendritic cells (DCs) to T cells for spontaneous immune response generation to effectively kill cancer cells remain challenging in cancer immunotherapy. Here, we report a general approach to genetically engineer DCs through silencing their YTHDF1 protein (an important reader protein responsible for RNA m⁶A methylation) expression via a dendrimeric non-viral vector to boost effective tumor immunotherapy. Poly(amidoamine) dendrimers of generation 5 were partially decorated with mannose and 1,3-propanesultone and then entrapped with gold (Au) nanoparticles. The created dendrimer nanoplatform has an Au core size of 1.8 nm; possesses desired stability, good cytocompatibility, and excellent YTHDF1 siRNA compression ability; and enables targeted gene silencing of DCs overexpressing mannose receptors to upregulate the expression of CD80 and CD86, markers of DCs maturation, potentially leading to tumor antigen cross-presentation. With these properties owned, the combination of YTHDF1 silencing of DCs with programmed cell death-ligand 1 antibody can boost the best immunotherapy of a xenografted melanoma tumor model through the created antitumor immune responses. Findings in this study demonstrate a general approach of genetic engineering of DCs via a dendrimeric non-viral vector to effectively boost antitumor immunotherapy.

Self-assembly of Peptide dendrimers and their bio-applications in theranostics

Nanotechnology has brought revolutionized advances in disease diagnosis and therapy. Self-assembled peptide dendrimers own novel physicochemical properties through the synergistic effects of the polypeptide chain, dendrimer and nano-structure, exhibiting great potential in theranostic. This review provides comprehensive insights into various peptide dendrimers for self-assembly. Their nanosize, morphology and composition are presented to understand self-assembly behaviors precisely. We further introduce the emerging theranostic applications based on specific imaging and efficient delivery recently.

Re-establishing the comprehension of phytomedicine and nanomedicine in inflammation-mediated cancer signaling

Recent mounting evidence has revealed extensive genetic heterogeneity within tumors that drive phenotypic variation affecting key cancer pathways, making cancer treatment extremely challenging. Diverse cancer types display resistance to treatment and show patterns of relapse following therapy. Therefore, efforts are required to address tumor heterogeneity by developing a broad-spectrum therapeutic approach that combines targeted therapies. Inflammation has been progressively documented as a vital factor in tumor advancement and has consequences in epigenetic variations that support tumor instigation, encouraging all the tumorigenesis phases. Increased DNA damage, disrupted DNA repair mechanisms, cellular proliferation, apoptosis, angiogenesis, and its incursion are a few pro-cancerous outcomes of chronic inflammation. A clear understanding of the cellular and molecular signaling mechanisms of tumor-endorsing inflammation is necessary for further expansion of anti-cancer therapeutics targeting the crosstalk between tumor development and inflammatory processes. Multiple inflammatory signaling pathways, such as the NF-κB signaling pathway, JAK-STAT signaling pathway, MAPK signaling, PI3K/AKT/mTOR signaling, Wnt signaling cascade, and TGF-β/Smad signaling, have been found to regulate inflammation, which can be modulated using various factors such as small molecule inhibitors, phytochemicals, recombinant cytokines, and nanoparticles in conjugation to phytochemicals to treat cancer. Researchers have identified multiple targets to specifically alter inflammation in cancer therapy to restrict malignant progression and improve the efficacy of cancer therapy. siRNA-and shRNA-loaded nanoparticles have been observed to downregulate STAT3 signaling pathways and have been employed in studies to target tumor malignancies. This review highlights the pathways involved in the interaction between tumor advancement and inflammatory progression, along with the novel approaches of nanotechnology-based drug delivery systems currently used to target inflammatory signaling pathways to combat cancer.

Peptide probes for proteases - innovations and applications for monitoring proteolytic activity

Proteases are excellent biomarkers for a variety of diseases, offer multiple opportunities for diagnostic applications and are valuable targets for therapy. From a chemistry-based perspective this review discusses and critiques the most recent advances in the field of substrate-based probes for the detection and analysis of proteolytic activity both in vitro and in vivo.

Investigating the properties of L-lysine dendrimers through physico-chemical characterisation techniques and atomistic molecular dynamics simulations

Poly(L-lysine) (PLL) dendrimers up to generation 6, both as their ammonium trifluoroacetate salts and their boc-protected intermediates were characterised using multi-detector size exclusion chromatography (MD-SEC) and Taylor dispersion analysis (TDA)...

Peptide Multimerization as Leads for Therapeutic Development

Multimerization of peptide structures has been a logical evolution in their development as potential therapeutic molecules. The multivalent properties of these assemblies have attracted much attention from researchers in the past and the development of more complex branching dendrimeric structures, with a wide array of biocompatible building blocks is revealing previously unseen properties and activities. These branching multimer and dendrimer structures can induce greater effect on cellular targets than monomeric forms and act as potent antimicrobials, potential vaccine alternatives and promising candidates in biomedical imaging and drug delivery applications. This review aims to outline the chemical synthetic innovations for the development of these highly complex structures and highlight the extensive capabilities of these molecules to rival those of natural biomolecules.

Polymeric Nanomaterials for Efficient Delivery of Antimicrobial Agents

Bacterial infections have threatened the lives of human beings for thousands of years either as major diseases or complications. The elimination of bacterial infections has always occupied a pivotal position in our history. For a long period of time, people were devoted to finding natural antimicrobial agents such as antimicrobial peptides (AMPs), antibiotics and silver ions or synthetic active antimicrobial substances including antimicrobial peptoids, metal oxides and polymers to combat bacterial infections. However, with the emergence of multidrug resistance (MDR), bacterial infection has become one of the most urgent problems worldwide. The efficient delivery of antimicrobial agents to the site of infection precisely is a promising strategy for reducing bacterial resistance. Polymeric nanomaterials have been widely studied as carriers for constructing antimicrobial agent delivery systems and have shown advantages including high biocompatibility, sustained release, targeting and improved bioavailability. In this review, we will highlight recent advances in highly efficient delivery of antimicrobial agents by polymeric nanomaterials such as micelles, vesicles, dendrimers, nanogels, nanofibers and so forth. The biomedical applications of polymeric nanomaterial-based delivery systems in combating MDR bacteria, anti-biofilms, wound healing, tissue engineering and anticancer are demonstrated. Moreover, conclusions and future perspectives are also proposed.

NCs-Delivered Pesticides: A Promising Candidate in Smart Agriculture

Pesticides have been used extensively in the field of plant protection to maximize crop yields. However, the long-term, unmanaged application of pesticides has posed severe challenges such as pesticide resistance, environmental contamination, risk in human health, soil degradation, and other important global issues. Recently, the combination of nanotechnology with plant protection strategies has offered new perspectives to mitigate these global issues, which has promoted a rapid development of NCs-based pesticides. Unlike certain conventional pesticides that have been applied inefficiently and lacked targeted control, pesticides delivered by nanocarriers (NCs) have optimized formulations, controlled release rate, and minimized or site-specific application. They are receiving increasing attention and are considered as an important part in sustainable and smart agriculture. This review discussed the limitation of traditional pesticides or conventional application mode, focused on the sustainable features of NCs-based pesticides such as improved formulation, enhanced stability under harsh condition, and controlled release/degradation. The perspectives of NCs-based pesticides and their risk assessment were also suggested in this view for a better use of NCs-based pesticides to facilitate sustainable, smart agriculture in the future.

Modular amphiphilic poly(aryl ether)-based supramolecular nanomicelles: an efficient endocytic drug carrier

A rationally designed amphiphilic poly(aryl ether)-based dendrimer self-assembles into nanomicelles and exhibits tunable morphology upon varying the hydrophilic chain length. The 30 nm-sized dendrimer nanomicelles successfully entrapped Doxorubicin, demonstrated the sustained release of Doxorubicin and can successfully penetrate cancer cells through caveolae-dependent endocytosis, compared to the free drug.

Active targeting strategy in nanomedicines using anti-EGFR ligands - A promising approach for cancer therapy and diagnosis

As active targeting using nanomedicines establishes itself as a strategy of choice in cancer therapy, several target receptors or ligands overexpressed in cancer cells have been identified and exploited. Among them, the epidermal growth factor receptor (EGFR) has emerged as one of the most promising oncomarkers for active targeting nanomedicines due to its overexpression and its active involvement in a wide range of cancer types. Henceforth, many novel EGFR-targeted nanomedicines for cancer therapy have been developed, giving encouraging results both in vitro and in vivo. This review focuses on different applications of such medicines in oncotherapy. On an important note, the contribution of EGFR-targeting ligands to final therapy efficacy along with current challenges and possible solutions or alternatives are emphasized.

Engineering of 177Lu-labeled gold encapsulated into dendrimeric nanomaterials for the treatment of lung cancer

As a novel type of theranostic radioactive agents, ¹⁷⁷Lu-labeled nanomaterials conjugated to macromolecules have been described. The study aimed to fabricate PAMAM-G4-(¹⁷⁷Lu-dendrimer)-bombesin-folate in the dendrimeric cavity, assess the radiopharmaceutical ability for specifically targeted radiotherapy and simultaneously detects gastrin-releasing peptide receptors (GRPR) and folate receptors (FRs) overexpressed in lung carcinoma cells, respectively. In an aqueous-basic media, p-SCN-benzyl-DOTA was conjugated to the dendrimer. This dendrimer was formed by activating the carboxylic acid groups of DOTA-folic acid and bombesin with HATU and conjugating them to develop the dendrimer. As part of this process, the conjugate was combined with 1% HAuCl₄, added NaBH₄ and filtered by ultrafiltration. Infrared, UV-Vis, TEM analysis, dynamic light scattering (DLS), and fluorescence spectroscopy were employed to observe the composition of the fabricated sample. Radio-labeled ¹⁷⁷LuCl₃ was used to label the conjugate, which was then evaluated using the radio-HPLC method. Findings demonstrated dendrimeric functionalization with remarkable radiochemical composition purity up to >96%. Because of fluorescence studies, it was determined that the occurrence of AuNMs in the dendrimeric cavities gives beneficial photo-physical characteristics to the radiopharmaceutical for bio-imaging. HEL-299 lung cancer cells exhibited a selective absorption of the drug (%). It might be helpful as nuclear and optical imaging agents for lung cancers that overexpress FRs and GRPR and as a specific target for radiation therapy if combined with folate-bombesin.

Phase equilibria and conformational behavior of dendrimers in porous media: Towards chromatographic analysis of dendrimers

HYPOTHESIS

The intricate entropy-enthalpy interplay of dendrimers confined in pores affects their conformation and retention in the porous stationary phase. This work aims at providing important insights into its impacts on partitioning and chromatographic separation in both size-exclusion chromatography (SEC) and interaction chromatography (IC) regimes.

SIMULATIONS

Using Monte Carlo (MC) simulations, we investigated the bulk-pore phase equilibria and the conformational behavior of flexible dendrimers differing in generation, in spacer length and in fraction of modified terminal groups interacting differently with pore walls than the majority building units.

FINDINGS

With increasing interaction strength, a distinct transition from a roughly spherical shape caused by simultaneous interactions with two walls to an ellipsoidal (or even disklike) conformation tenaciously adhering to only one wall was observed for moderately confined dendrimers. The strongly deformed dendrimers subjected to severe confinement gain high energy and the samples differing in the degree of modification become chromatographically discernable thanks to large energy differences. Consequently, our results suggest that the column fillings with fairly narrow pores which are ineffective in SEC, are highly efficient separation media for dendrimer studies by IC above the critical adsorption point (CAP). Overall, our simulations reveal useful information for advancing and optimizing experimental liquid chromatography studies of dendrimers.

Dendrimers as Non-Viral Vectors in Gene-Directed Enzyme Prodrug Therapy

Gene-directed enzyme prodrug therapy (GDEPT) has been intensively studied as a promising new strategy of prodrug delivery, with its main advantages being represented by an enhanced efficacy and a reduced off-target toxicity of the active drug. In recent years, numerous therapeutic systems based on GDEPT strategy have entered clinical trials. In order to deliver the desired gene at a specific site of action, this therapeutic approach uses vectors divided in two major categories, viral vectors and non-viral vectors, with the latter being represented by chemical delivery agents. There is considerable interest in the development of non-viral vectors due to their decreased immunogenicity, higher specificity, ease of synthesis and greater flexibility for subsequent modulations. Dendrimers used as delivery vehicles offer many advantages, such as: nanoscale size, precise molecular weight, increased solubility, high load capacity, high bioavailability and low immunogenicity. The aim of the present work was to provide a comprehensive overview of the recent advances regarding the use of dendrimers as non-viral carriers in the GDEPT therapy.

Cellular and Molecular Targeted Drug Delivery in Central Nervous System Cancers: Advances in Targeting Strategies

Central nervous system (CNS) cancers are among the most common and treatment-resistant diseases. The main reason for the low treatment efficiency of the disorders is the barriers against targeted delivery of anticancer agents to the site of interest, including the blood-brain barrier (BBB) and blood-brain tumor barrier (BBTB). BBB is a strong biological barrier separating circulating blood from brain extracellular fluid that selectively and actively prevents cytotoxic agents and majority of anticancer drugs from entering the brain. BBB and BBTB are the major impediments against targeted drug delivery into CNS tumors. Nanotechnology and its allied modalities offer interesting and effective delivery strategies to transport drugs across BBB to reach brain tissue. Integrating anticancer drugs into different nanocarriers improves the delivery performance of the resultant compounds across BBB. Surface engineering of nanovehicles using specific ligands, antibodies and proteins enhances the BBB crossing efficacy as well as selective and specific targeting to the target cancerous tissues in CNS tumors. Multifunctional nanoparticles (NPs) have brought revolutionary advances in targeted drug delivery to brain tumors. This study reviews the main anatomical, physiological and biological features of BBB and BBTB in drug delivery and the recent advances in targeting strategies in NPs-based drug delivery for CNS tumors. Moreover, we discuss advances in using specific ligands, antibodies, and surface proteins for designing and engineering of nanocarriers for targeted delivery of anticancer drugs to CNS tumors. Finally, the current clinical applications and the perspectives in the targeted delivery of therapeutic molecules and genes to CNS tumors are discussed.

Non-viral Suicide Gene Therapy: Cytosine Deaminase Gene Directed by VEGF Promoter and 5-fluorocytosine as a Gene Directed Enzyme/prodrug System in Breast Cancer Model

The present study investigated the potential of vascular endothelial growth factor (VEGF) promoter to derive cytosine deaminase (CD) transfected by polyamidoamine (G4-PAMAM) dendrimers to 4T1 murine breast cancer cell line as gene-directed enzyme/prodrug therapy. The VEGF promoter and cytosine deaminase gene were cloned into the pEGFP-N1vector from the genomic DNA of 4T1 and E. coli, respectively. The frequency of transfection for VEGF-CD-pEGFP-N1 and pEGFP-N1- CD treated groups was 35±3 and 36±4, respectively. MTT assay was perform to evaluate the cytotoxic effects of converted 5-flurocytosine on 4T1 cells. Also, the optimal concentration of 5-FC in 4T1 cells transfected by VEGF-CD-pEGFP-N1 plasmid was evaluated. The GFP expression of transfected 4T1 cells by VEGF-CD-pEGFP-N1were observed by fluorescent microscopy and flowcytometry. Results demonstrated that the suicide CD gene was successfully expressed in 4T1 cells determined by RT-PCR and GFP expression. A concentration of 200 μg/ml 5-FC was identified as optimal dose of prodrug. Furthermore, the CD/5-FC enzyme/prodrug system not only demonstrated toxicity on transformed 4T1 cells but also exerted a 'bystander effect' determined by MTT assay. The results showed that by 35% transfection with VEGF-CD-pEGFP-N1and CD-pEGFP-N1 plasmids, 80% and 90% inhibition of the cells growth occurred, respectively.

Delivery of siHIF-1α to Reconstruct Tumor Normoxic Microenvironment for Effective Chemotherapeutic and Photodynamic Anticancer Treatments

The tumor hypoxic microenvironment not only induces genetic and epigenetic changes in tumor cells, immature vessels formation for oxygen demand, but also compromises the efficiency of therapeutic interventions. On the other hand, conventional therapeutic approaches which kill tumor cells or destroy tumor blood vessels to block nutrition and oxygen supply usually facilitate even harsher microenvironment. Thus, simultaneously relieving the strained response of tumor cells and blood vessels represents a promising strategy to reverse the adverse tumor hypoxic microenvironment. In the present study, an integrated amphiphilic system (RSCD) is designed based on Angiotensin II receptor blocker candesartan for siRNA delivery against the hypoxia-inducible factor-1 alpha (HIF-1α), aiming at both vascular and cellular "relaxation" to reconstruct a tumor normoxic microenvironment. Both in vitro and in vivo studies have confirmed that the hypoxia-inducible HIF-1α expression is down-regulated by 70% and vascular growth is inhibited by 60%. The "relaxation" therapy enables neovascularization with more complete and organized structures to obviously increase the oxygen level inside tumor, which results in a 50% growth inhibition. Moreover, reconstruction of tumor microenvironment enhances tumor-targeted drug delivery, and significantly improves the chemotherapeutic and photodynamic anticancer treatments.