Dendritic Polymers for Theranostics

Current status and future directions of nanovaccine for cancer: a bibliometric analysis during 2004-2023

Background

Nanovaccine treatment is an exciting area of research in immunology and personalized medicine, holding great promise for enhancing immune responses and targeting specific diseases. Their small size allows efficient uptake by immune cells, leading to robust immune activation. They can incorporate immune-stimulating molecules to boost vaccine efficacy. Therefore, nanovaccine can be personalized to target tumor-specific antigens, activating the immune system against cancer cells. Currently, there have been ample evidence showing the effectiveness and potential of nanovaccine as a treatment for cancer. However, there was rare bibliometric analysis of nanovaccine for cancer. Here we performed a bibliometric and visual analysis of published studies related to nanovaccine treatment for cancer, providing the trend of future development of nanovaccine.

Methods

We collected the literatures based on the Web of Science Core Collection SCI-Expanded database. The bibliometric analysis was performed via utilizing visualization analysis tools VOSviewer, Co-Occurrence (COOC), Citespace, Bibliometrix (R-Tool of R-Studio), and HitCite.

Results

A total of 517 literatures were included in this study. China is the country with the most publications and the highest total local citation score (TLCS). The Chinese Academy of Sciences holds the largest research count in this field and the most prolific author is Deling Kong from Nankai University. The most prominent journal for publishing in this area is Biomaterials. The researches mainly focus on the therapeutic process of tumor nanovaccines, the particle composition and the application of nanovaccines, suggesting the potential hotspots and trends of nanovaccine.

Conclusion

In this study, we summarized the characteristics and variation trends of publications involved in nanovaccine, and categorized the most influential countries, institutions, authors, journals, hotspots and trends regarding the nanovaccine for cancer. With the continuous development of nanomaterials and tumor immunotherapy, nanovaccine for cancer provides a research field of significant clinical value and potential application.

Biogenic metallic nanoparticles: from green synthesis to clinical translation

Biogenic metallic nanoparticles (NPs) have garnered significant attention in recent years due to their unique properties and various applications in different fields. NPs, including gold, silver, zinc oxide, copper, titanium, and magnesium oxide NPs, have attracted considerable interest. Green synthesis approaches, utilizing natural products, offer advantages such as sustainability and environmental friendliness. The theranostics applications of these NPs hold immense significance in the fields of medicine and diagnostics. The review explores intricate cellular uptake pathways, internalization dynamics, reactive oxygen species generation, and ensuing inflammatory responses, shedding light on the intricate mechanisms governing their behaviour at a molecular level. Intriguingly, biogenic metallic NPs exhibit a wide array of applications in medicine, including but not limited to anti-inflammatory, anticancer, anti-diabetic, anti-plasmodial, antiviral properties and radical scavenging efficacy. Their potential in personalized medicine stands out, with a focus on tailoring treatments to individual patients based on these NPs' unique attributes and targeted delivery capabilities. The article culminates in emphasizing the role of biogenic metallic NPs in shaping the landscape of personalized medicine. Harnessing their unique properties for tailored therapeutics, diagnostics and targeted interventions, these NPs pave the way for a paradigm shift in healthcare, promising enhanced efficacy and reduced adverse effects.

Internal Light Sources-Mediated Photodynamic Therapy Nanoplatforms: Hope for the Resolution of the Traditional Penetration Problem

Photodynamic therapy (PDT) is an alternative cancer treatment technique with a noninvasive nature, high selectivity, and minimal adverse effects. The indispensable light source used in PDT is a critical factor in determining the energy conversion of photosensitizers (PSs). Traditional light sources are primarily concentrated in the visible light region, severely limiting their penetration depth and making them prone to scattering and absorption when applied to biological tissues. For that reason, its efficacy in treating deep-seated lesions is often inadequate. Self-exciting PDT, also known as auto-PDT (APDT), is an attractive option for circumventing the limited penetration depth of traditional PDT and has acquired significant attention. APDT employs depth-independent internal light sources to excite PSs through resonance or radiative energy transfer. APDT has considerable potential for treating deep-tissue malignancies. To facilitate many researchers' comprehension of the latest research progress in this field and inspire the emergence of more novel research results. This review introduces internal light generation mechanisms and characteristics and provides an overview of current research progress based on the recently reported APDT nanoplatforms. The current challenges and possible solutions of APDT nanoplatforms are also presented and provide insights for future research in the final section of this article.

Janus Dendrimers as Nanocarriers of Ibuprofen, Chlorambucil and their Anticancer Activity

BACKGROUND

Janus Dendrimer represents a novel class of synthetic nanocarriers. Since it is possible to introduce multiple drugs and target moieties, this helps the designing of new biocompatible forms with pharmacological activities comprised of different drugs with tailor-made functionalities, such as anticancer and nonsteroidal anti-inflammatory, which could improve the anticancer activity with less toxicity.

AIMS

This study aimed to determine the anticancer activity of the Janus dendrimers formed by two dendrons. One dendron conjugates with chlorambucil, and the other dendron conjugates with Ibuprofen.

METHODS

The cytotoxicity of the drug carriers was determined by the sulforhodamine B (SRB) assay for three cell lines. PC-3 (human prostatic adenocarcinoma), HCT-15 (human colorectal adenocarcinoma), MFC-7 (human breast cancer) and the COS-7 African green monkey kidney (used as a control) cell lines were seeded into 96-well plates at a density of 5x103 cells/well and cultured for 24 h before use. All the obtained compounds were characterized by 1H and 13C NMR one and two dimensions, UVvis, FTIR, MALDI-TOF, Electrospray mass, and FAB+. Microscopic images were taken in an Inverted microscope Nikon, Diaphot 300, 10x4 in culture medium.

RESULTS

Janus dendrimers (G1 and G2) were synthesized via an azide-alkyne click-chemistry reaction attaching on one face dendrons with ibuprofen molecules and, on the other face, attached a chlorambucil- derivative. The IC50 behavior of the conjugates of the first and second generations showed anticancer activity against PC-3, HCT-15, and MFC-7 cell lines. The second generation was more active against PC-3, HCT-15 and MFC-7 with IC50 of 3.8±0.5, 3.0±0.2 and 3.7 ± 1.1 mM, respectively.

CONCLUSION

The new Janus dendrimers with anticancer chlorambucil and nonsteroidal antiinflammatory Ibuprofen can improve the anticancer activity of chlorambucil with less toxicity.

FUTURE PROSPECTS

Now, we are working on the synthesis of new Janus dendrimers using the most effective and fine methods. Moreover, we hope that we shall be able to obtain different generations that are more selective against cancer cells.

Revealing the Structure Formation on Polyglycerol Citrate Polymers-An Environmentally Friendly Polyester as a Seed-Coating Material

A detailed structural investigation of a promising bio-based polymer, polyglycerol citrate polyester, obtained by the bulk polycondensation of glycerol (Gly) against citric acid (Cit) under mild reaction was performed. The reaction in conditions with and without catalyst use (sulfuric acid, H2SO4) was investigated, showing evidence that it is possible to modify the polymer solubility according to the ratio and catalyst utilization. 13C and 1H NMR indicated that synthesis catalyzed with Cit excess leads to higher esterification degrees of citrate groups. In contrast, the Gly moieties are more prominent in catalyzed polymers regardless of the excess monomers. Overall, a successful conversion of Gly and Cit into polyesters was attained even without catalysis, enabling a simple route for the large-scale production of this green material to be used as a coating material. This polymer has been shown to be well-suited for coating seeds and might be a promising material for similar agricultural applications. Tests on soybean seed coating with a PGCit solution of 75% indicated that the seed quality and germination rate were not affected by the PGCit coating, concluding that this polymer is suitable for this application.

Actinide Ion (Americium-241 and Uranium-232) Interaction with Hybrid Silica-Hyperbranched Poly(ethylene imine) Nanoparticles and Xerogels

The binding of actinide ions (Am(III) and U(VI)) in aqueous solutions by hybrid silica-hyperbranched poly(ethylene imine) nanoparticles (NPs) and xerogels (XGs) has been studied by means of batch experiments at different pH values (4, 7, and 9) under ambient atmospheric conditions. Both materials present relatively high removal efficiency at pH 4 and pH 7 (>70%) for Am(III) and U(VI). The lower removal efficiency for the nanoparticles is basically associated with the compact structure of the nanoparticles and the lower permeability and access to active amine groups compared to xerogels, and the negative charge of the radionuclide species is formed under alkaline conditions (e.g., UO2(CO3)34- and Am(CO3)2-). Generally, the adsorption process is relatively slow due to the very low radionuclide concentrations used in the study and is basically governed by the actinide diffusion from the aqueous phase to the solid surface. On the other hand, adsorption is favored with increasing temperature, assuming that the reaction is endothermic and entropy-driven, which is associated with increasing randomness at the solid-liquid interphase upon actinide adsorption. To the best of our knowledge, this is the first study on hybrid silica-hyperbranched poly(ethylene imine) nanoparticle and xerogel materials used as adsorbents for americium and uranium at ultra-trace levels. Compared to other adsorbent materials used for binding americium and uranium ions, both materials show far higher binding efficiency. Xerogels could remove both actinides even from seawater by almost 90%, whereas nanoparticles could remove uranium by 80% and americium by 70%. The above, along with their simple derivatization to increase the selectivity towards a specific radionuclide and their easy processing to be included in separation technologies, could make these materials attractive candidates for the treatment of radionuclide/actinide-contaminated water.

Glutathione Programmed Mitochondria Targeted Delivery of Lonidamine for Effective Against Triple Negative Breast Cancer

Introduction

Mitochondria are a significant target of lonidamine (LND). However, its limited solubility and inability to specifically target mitochondria, LND can lead to hepatic toxicity and has shown only modest anticancer activity. The objective of this study is to establish a glutathione programmed mitochondria targeted delivery of LND for the effective treatment of triple negative breast cancer (TNBC).

Methods

In this study, LND was encapsulated in poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) wrapped with mitochondria-targeting short-chain triphenylphosphonium-tocopherol polyethylene glycol succinate (TPP-TPGS, TPS) and tumor-targeting long-chain 1, 2-distearoyl-sn-glycero-3-phosphoethanolamine-S-S-polyethylene glycol-R6RGD (DSPE-S-S-PEG₂₀₀₀-R6RGD, DSSR), which were designated as LND-PLGA/TPS/DSSR NPs. The release behavior was evaluated, and cellular uptake, in vitro and in vivo antitumor activity of nanoparticles were investigated. The mechanism, including apoptosis of tumor cells and mitochondrial damage and respiratory rate detection, was also further investigated.

Results

LND-PLGA/TPS/DSSR NPs were successfully prepared, and characterization revealed that they are globular particles with smooth surfaces and an average diameter of about 250 nm. Long-chain DSSR in LND-PLGA/TPS/DSSR NPs prevented positively charged LND-PLGA/TPS NPs from being cleared by the reticuloendothelial system. Furthermore, LND release rate from NPs at pH 8.0 was significantly higher than that at pH 7.4 and 5.5, which demonstrated specific LND release in mitochondria and prevented LND leakage in cytoplasm and lysosome. NPs could locate in mitochondria, and the released LND triggered apoptosis of tumor cells by damaging mitochondria and releasing apoptosis-related proteins. In addition, in TNBC mice model, programmed mitochondria targeted NPs improved efficacy and reduced LND toxicity.

Conclusion

LND-PLGA/TPS/DSSR NPs may be a useful system and provide an effective approach for the treatment of TNBC.

Comparative Study of the U(VI) Adsorption by Hybrid Silica-Hyperbranched Poly(ethylene imine) Nanoparticles and Xerogels

Two different silica conformations (xerogels and nanoparticles), both formed by the mediation of dendritic poly (ethylene imine), were tested at low pHs for problematic uranyl cation sorption. The effect of crucial factors, i.e., temperature, electrostatic forces, adsorbent composition, accessibility of the pollutant to the dendritic cavities, and MW of the organic matrix, was investigated to determine the optimum formulation for water purification under these conditions. This was attained with the aid of UV-visible and FTIR spectroscopy, dynamic light scattering (DLS), ζ-potential, liquid nitrogen (LN₂) porosimetry, thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). Results highlighted that both adsorbents have extraordinary sorption capacities. Xerogels are cost-effective since they approximate the performance of nanoparticles with much less organic content. Both adsorbents could be used in the form of dispersions. The xerogels, though, are more practicable materials since they may penetrate the pores of a metal or ceramic solid substrate in the form of a precursor gel-forming solution, producing composite purification devices.

An evolving perspective on novel modified release drug delivery systems for inhalational therapy

INTRODUCTION

Drugs delivered via the lungs are predominantly used to treat various respiratory disorders, including asthma, chronic obstructive pulmonary diseases, respiratory tract infections and lung cancers, and pulmonary vascular diseases such as pulmonary hypertension. To treat respiratory diseases, targeted, modified or controlled release inhalation formulations are desirable for improved patient compliance and superior therapeutic outcome.

AREAS COVERED

This review summarizes the important factors that have an impact on the inhalable modified release formulation approaches with a focus toward various formulation strategies, including dissolution rate-controlled systems, drug complexes, site-specific delivery, drug-polymer conjugates, and drug-polymer matrix systems, lipid matrix particles, nanosystems, and formulations that can bypass clearance via mucociliary system and alveolar macrophages.

EXPERT OPINION

Inhaled modified release formulations can potentially reduce dosing frequency by extending drug's residence time in the lungs. However, inhalable modified or controlled release drug delivery systems remain unexplored and underdeveloped from the commercialization perspective. This review paper addresses the current state-of-the-art of inhaled controlled release formulations, elaborates on the avenues for developing newer technologies for formulating various drugs with tailored release profiles after inhalational delivery and explains the challenges associated with translational feasibility of modified release inhalable formulations.

Dendritic Polymers in Tissue Engineering: Contributions of PAMAM, PPI PEG and PEI to Injury Restoration and Bioactive Scaffold Evolution

The capability of radially polymerized bio-dendrimers and hyperbranched polymers for medical applications is well established. Perhaps the most important implementations are those that involve interactions with the regenerative mechanisms of cells. In general, they are non-toxic or exhibit very low toxicity. Thus, they allow unhindered and, in many cases, faster cell proliferation, a property that renders them ideal materials for tissue engineering scaffolds. Their resemblance to proteins permits the synthesis of derivatives that mimic collagen and elastin or are capable of biomimetic hydroxy apatite production. Due to their distinctive architecture (core, internal branches, terminal groups), dendritic polymers may play many roles. The internal cavities may host cell differentiation genes and antimicrobial protection drugs. Suitable terminal groups may modify the surface chemistry of cells and modulate the external membrane charge promoting cell adhesion and tissue assembly. They may also induce polymer cross-linking for healing implementation in the eyes, skin, and internal organ wounds. The review highlights all the different categories of hard and soft tissues that may be remediated with their contribution. The reader will also be exposed to the incorporation of methods for establishment of biomaterials, functionalization strategies, and the synthetic paths for organizing assemblies from biocompatible building blocks and natural metabolites.

Dendrimers as Modifiers of Inorganic Nanoparticles for Therapeutic Delivery in Cancer

The formulation of nanoscale systems with well-defined sizes and shapes is of great interest in applications such as drug and gene delivery, diagnostics and imaging. Dendrimers are polymers that have attracted interest due to their size, shape, branching length, amine density, and surface functionalities. These unique characteristics of dendrimers set them apart from other polymers, their ability to modify nanoparticles (NPs) for biomedical applications. Dendrimers are spherical with multiple layers over their central core, each representing a generation. Their amphiphilic nature and hollow structure allow for the incorporation of multiple drugs or genes, in addition to enabling easy surface modification with cellular receptor-targeting moieties to ensure site-specific delivery of therapeutics. Dendrimers are employed in chemotherapeutic applications for the delivery of anticancer drugs. There are many inorganic NPs currently being investigated for cancer therapy, each with their own unique biological, chemical, and physical properties. To favor biomedical applications, inorganic NPs require suitable polymers to ensure stability, biodegradability and target specificity. The success of dendrimers is dependent on their unique structure, good bioavailability and stability. In this review, we describe the properties of dendrimers and their use as modifiers of inorganic NPs for enhanced therapeutic delivery. Herein, we review the significant developments in this area from 2015 to 2022. Databases including Web of Science, Scopus, Google Scholar, Science Direct, BioMed Central (BMC), and PubMed were searched for articles using dendrimers, inorganic nanoparticles and cancer as keywords.

Aggregation-Induced Emission Luminogens for Enhanced Photodynamic Therapy: From Organelle Targeting to Tumor Targeting

Photodynamic therapy (PDT) has attracted much attention in the field of anticancer treatment. However, PDT has to face challenges, such as aggregation caused by quenching of reactive oxygen species (ROS), and short ¹O₂ lifetime, which lead to unsatisfactory therapeutic effect. Aggregation-induced emission luminogen (AIEgens)-based photosensitizers (PSs) showed enhanced ROS generation upon aggregation, which showed great potential for hypoxic tumor treatment with enhanced PDT effect. In this review, we summarized the design strategies and applications of AIEgen-based PSs with improved PDT efficacy since 2019. Firstly, we introduce the research background and some basic knowledge in the related field. Secondly, the recent approaches of AIEgen-based PSs for enhanced PDT are summarized in two categories: (1) organelle-targeting PSs that could cause direct damage to organelles to enhance PDT effects, and (2) PSs with tumor-targeting abilities to selectively suppress tumor growth and reduce side effects. Finally, current challenges and future opportunities are discussed. We hope this review can offer new insights and inspirations for the development of AIEgen-based PSs for better PDT effect.

Cyclodextrin-Based Polymeric Materials Bound to Corona Protein for Theranostic Applications

Cyclodextrins (CDs) are cyclic oligosaccharide structures that could be used for theranostic applications in personalized medicine. These compounds have been widely utilized not only for enhancing drug solubility, stability, and bioavailability but also for controlled and targeted delivery of small molecules. These compounds can be complexed with various biomolecules, such as peptides or proteins, via host-guest interactions. CDs are amphiphilic compounds with water-hating holes and water-absorbing surfaces. Architectures of CDs allow the drawing and preparation of CD-based polymers (CDbPs) with optimal pharmacokinetic and pharmacodynamic properties. These polymers can be cloaked with protein corona consisting of adsorbed plasma or extracellular proteins to improve nanoparticle biodistribution and half-life. Besides, CDs have become famous in applications ranging from biomedicine to environmental sciences. In this review, we emphasize ongoing research in biomedical fields using CD-based centered, pendant, and terminated polymers and their interactions with protein corona for theranostic applications. Overall, a perusal of information concerning this novel approach in biomedicine will help to implement this methodology based on host-guest interaction to improve therapeutic and diagnostic strategies.

The effect of surface modification of dendronized gold nanoparticles on activation and release of pyroptosis-inducing pro-inflammatory cytokines in presence of bacterial lipopolysaccharide in monocytes

Biomedical applications of gold nanoparticles (AuNPs) may be limited by their toxicological effects. Although surface-modified AuNPs can induce apoptosis, less is known about whether they can induce other types of cell death. Pyroptosis, an inflammatory type of programmed cell death, can be induced in immune cells, especially macrophages, by bacterial endotoxins. Therefore, in this study, dendronized AuNPs were combined with bacterial lipopolysaccharides (LPSs) as the main stimulators of pro-inflammatory responses to test the induction of pyroptosis in THP-1 myeloid cell line. These AuNPs induced caspase-1 activity (3-4 times more compared to control) and enhanced the release of interleukin (IL)-18 and IL-1β without inducing gasdermin D cleavage and related pore formation. The production of pro-inflammatory cytokines occurred mainly visible during LPS treatment, although their secretion was observed only after administration of dendronized AuNPs (release of IL-1β to supernatant up to 80 pg/mL). These findings suggest that dendronized AuNPs can induce pyroptosis-like inflammatory mechanisms and that these mechanisms are enhanced in the presence of bacterial LPS. The intensity of this effect was dependent on AuNP surface modification. These results shed new light on the cytotoxicity of metal NPs, including immune responses, indicating that surface modifications play crucial roles in their nanotoxicological effects.

Advanced Polymeric Nanocomposites for Water Treatment Applications: A Holistic Perspective

Water pollution remains one of the greatest challenges in the modern era, and water treatment strategies have continually been improved to meet the increasing demand for safe water. In the last few decades, tremendous research has been carried out toward developing selective and efficient polymeric adsorbents and membranes. However, developing non-toxic, biocompatible, cost-effective, and efficient polymeric nanocomposites is still being explored. In polymer nanocomposites, nanofillers and/or nanoparticles are dispersed in polymeric matrices such as dendrimer, cellulose, resins, etc., to improve their mechanical, thermophysical, and physicochemical properties. Several techniques can be used to develop polymer nanocomposites, and the most prevalent methods include mixing, melt-mixing, in-situ polymerization, electrospinning, and selective laser sintering techniques. Emerging technologies for polymer nanocomposite development include selective laser sintering and microwave-assisted techniques, proffering solutions to aggregation challenges and other morphological defects. Available and emerging techniques aim to produce efficient, durable, and cost-effective polymer nanocomposites with uniform dispersion and minimal defects. Polymer nanocomposites are utilized as filtering membranes and adsorbents to remove chemical contaminants from aqueous media. This study covers the synthesis and usage of various polymeric nanocomposites in water treatment, as well as the major criteria that influence their performance, and highlights challenges and considerations for future research.

Baseline and time-updated factors in preclinical development of anionic dendrimers as successful anti-HIV-1 vaginal microbicides

Although a wide variety of topical microbicides provide promising in vitro and in vivo efficacy, most of them failed to prevent sexual transmission of human immunodeficiency virus type 1 (HIV-1) in human clinical trials. In vitro, ex vivo, and in vivo models must be optimized, considering the knowledge acquired from unsuccessful and successful clinical trials to improve the current gaps and the preclinical development protocols. To date, dendrimers are the only nanotool that has advanced to human clinical trials as topical microbicides to prevent HIV-1 transmission. This fact demonstrates the importance and the potential of these molecules as microbicides. Polyanionic dendrimers are highly branched nanocompounds with potent activity against HIV-1 that disturb HIV-1 entry. Herein, the most significant advancements in topical microbicide development, trying to mimic the real-life conditions as closely as possible, are discussed. This review also provides the preclinical assays that anionic dendrimers have passed as microbicides because they can improve current antiviral treatments' efficacy. This article is categorized under: Nanotechnology Approaches to Biology > Nanoscale Systems in Biology Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease Toxicology and Regulatory Issues in Nanomedicine > Regulatory and Policy Issues in Nanomedicine.

Hyperbranched polymers as superior adsorbent for the treatment of dyes in water

The effective control on environmental pollutants is crucial for the proper management of diverse environmental systems (e.g., soil, water, and air). In this respect, the utility of various functional materials such as hyperbranched polymers (HPs) has been recognized due to their great potentil as adsorbent for the mitigation of numerous environmental pollutants. Here, we highlight the latest progress achieved in the design and construction of HPs with high adsorption potentials. We focus on adsorption mechanisms, functionalization methods, the role of functional groups in adsorption capacity, and the choice of HPs in adsorption of cationic and anionic dyes. Recent published reports are reviewed to quantify and qualify the removal efficiency of pollutants through adsorption. We also evaluate the adsorbing efficiency of the constructed HPs and compared their performance with other such systems. The utilization potential of new materials (magnetic, polar, and biological) is highlighted along with the methods needed for their preparation and/or modification (surface, end-group, and zwitterionic) for the construction of efficient adsorbing systems. Finally, the advantages and limitations of adsorbing systems are described along with the existing challenges to help establish guidelines for future research. This article is thus expected to offer new path and guidance for developing advanced HP-based adsorbents.

Dendrimers as Antiamyloid Agents

Dendrimer-protein conjugates have significant prospects for biological applications. The complexation changes the biophysical behavior of both proteins and dendrimers. The dendrimers could influence the secondary structure of proteins, zeta-potential, distribution of charged regions on the surface, the protein-protein interactions, etc. These changes offer significant possibilities for the application of these features in nanotheranostics and biomedicine. Based on the dendrimer-protein interactions, several therapeutic applications of dendrimers have emerged. Thus, the formation of stable complexes retains the disordered proteins on the aggregation, which is especially important in neurodegenerative diseases. To clarify the origin of these properties and assess the efficiency of action, the mechanism of protein-dendrimer interaction and the nature and driving force of binding are considered in this review. The review outlines the antiamyloid activity of dendrimers and discusses the effect of dendrimer structures and external factors on their antiamyloid properties.

Organic/Inorganic Self-Assembled Hybrid Nano-Architectures for Cancer Therapy Applications

Since the conceptualization of nanomedicine, numerous nanostructure-mediated drug formulations have progressed into clinical trials for treating cancer. However, recent clinical trial results indicate such kind of drug formulations has a limited improvement on the antitumor efficacy. This is due to the biological barriers associated with those formulations, for example, circulation stability, extravasation efficiency in tumor, tumor penetration ability, and developed multi-drug resistance. When employing for nanomedicine formulations, pristine organic-based and inorganic-based nanostructures have their own limitations. Accordingly, organic/inorganic (O/I) hybrids have been developed to integrate the merits of both, and to minimize their intrinsic drawbacks. In this context, the recent development in O/I hybrids resulting from a self-assembly strategy will be introduced. Through such a strategy, organic and inorganic building blocks can be self-assembled via either chemical covalent bonds or physical interactions. Based on the self-assemble procedure, the hybridization of four organic building blocks including liposomes, micelles, dendrimers, and polymeric nanocapsules with five functional inorganic nanoparticles comprising gold nanostructures, magnetic nanoparticles, carbon-based materials, quantum dots, and silica nanoparticles will be highlighted. The recent progress of these O/I hybrids in advanced modalities for combating cancer, such as, therapeutic agent delivery, photothermal therapy, photodynamic therapy, and immunotherapy will be systematically reviewed.

Stimuli-Responsive Polymeric Nanoplatforms for Cancer Therapy

Polymeric nanoparticles have been widely used as carriers of drugs and bioimaging agents due to their excellent biocompatibility, biodegradability, and structural versatility. The principal application of polymeric nanoparticles in medicine is for cancer therapy, with increased tumor accumulation, precision delivery of anticancer drugs to target sites, higher solubility of pharmaceutical properties and lower systemic toxicity. Recently, the stimuli-responsive polymeric nanoplatforms attracted more and more attention because they can change their physicochemical properties responding to the stimuli conditions, such as low pH, enzyme, redox agents, hypoxia, light, temperature, magnetic field, ultrasound, and so on. Moreover, the unique properties of stimuli-responsive polymeric nanocarriers in target tissues may significantly improve the bioactivity of delivered agents for cancer treatment. This review introduces stimuli-responsive polymeric nanoparticles and their applications in tumor theranostics with the loading of chemical drugs, nucleic drugs and imaging molecules. In addition, we discuss the strategy for designing multifunctional polymeric nanocarriers and provide the perspective for the clinical applications of these stimuli-responsive polymeric nanoplatforms.

Photoresponsive metallopolymer nanoparticles for cancer theranostics

Over the past decades, transition metal complexes have been successfully used in anticancer phototherapies. They have shown promising properties in many different areas including photo-induced ligand exchange or release, rich excited state behavior, and versatile biochemical properties. When encorporated into polymeric frameworks and become part of nanostructures, photoresponsive metallopolymer nanoparticles (MPNs) show enhanced water solubility, extended blood circulation and increased tumor-specific accumulation, which greatly improves the tumor therapeutic effects compared to low-molecule-weight metal complexes. In this review, we aim to present the recent development of photoresponsive MPNs as therapeutic nanomedicines. This review will summarize four major areas separately, namely platinum-containing polymers, zinc-containing polymers, iridium-containing polymers and ruthenium-containing polymers. Representative MPNs of each type are discussed in terms of their design strategies, fabrication methods, and working mechanisms. Current challenges and future perspectives in this field are also highlighted.

Application of Dendrimers for Treating Parasitic Diseases

Despite advances in medical knowledge, parasitic diseases remain a significant global health burden and their pharmacological treatment is often hampered by drug toxicity. Therefore, drug delivery systems may provide useful advantages when used in combination with conventional therapeutic compounds. Dendrimers are three-dimensional polymeric structures, characterized by a central core, branches and terminal functional groups. These nanostructures are known for their defined structure, great water solubility, biocompatibility and high encapsulation ability against a wide range of molecules. Furthermore, the high ratio between terminal groups and molecular volume render them a hopeful vector for drug delivery. These nanostructures offer several advantages compared to conventional drugs for the treatment of parasitic infection. Dendrimers deliver drugs to target sites with reduced dosage, solving side effects that occur with accepted marketed drugs. In recent years, extensive progress has been made towards the use of dendrimers for therapeutic, prophylactic and diagnostic purposes for the management of parasitic infections. The present review highlights the potential of several dendrimers in the management of parasitic diseases.

Dendrimer Architectonics to Treat Cancer and Neurodegenerative Diseases with Implications in Theranostics and Personalized Medicine

Integration of diagnostic and therapeutic functions in a single platform namely theranostics has become a cornerstone for personalized medicine. Theranostics platform facilitates noninvasive detection and treatment while allowing the monitoring of disease progression and therapeutic efficacy in case of chronic conditions of cancer and Alzheimer's disease (AD). Theranostic tools function by themselves or with the aid of carrier, viz. liposomes, micelles, polymers, or dendrimers. The dendrimer architectures (DA) are well-characterized molecular nanoobjects with a large number of terminal functional groups to enhance solubility and offer multivalency and multifunctional properties. Various noninvasive diagnostic tools like magnetic resonance imaging (MRI), computed tomography (CT), gamma scintigraphy, and optical techniques have been accomplished utilizing DAs for simultaneous imaging and drug delivery. Obstacles in the formulation design, drug loading, payload delivery, biocompatibility, overcoming cellular membrane and blood-brain barrier (BBB), and systemic circulation remain a bottleneck in translational efforts. This review focuses on the diagnostic, therapeutic and theranostic potential of DA-based nanocarriers in treating cancer and neurodegenerative disorders like AD and Parkinson's disease (PD), among others. In view of the inverse relationship between cancer and AD, designing suitable DA-based theranostic nanodrug with high selectivity has tremendous implications in personalized medicine to treat cancer and neurodegenerative disorders.

Polymers and boron neutron capture therapy (BNCT): a potent combination

This review describes the latest polymeric systems used as boron transporters for boron neutron capture therapy.

A Highly Sensitive "on-off" Time-Resolved Phosphorescence Sensor Based on Aptamer Functionalized Magnetite Nanoparticles for Cadmium Detection in Food Samples

Cadmium contamination is a severe threat to food safety. Therefore, the development of sensitive and selective cadmium detection strategies is urgently required. The elimination of background autofluorescence generated from the food matrix is critical to the optical assay for cadmium detection. Herein, a time-resolved phosphorescence sensor based on an "on-off" strategy was developed for cadmium determination in food samples. The phosphorescence nanoparticles were used as a luminous material to minimize the interference of background autofluorescence. The cadmium-binding aptamer was immobilized onto the magnetic beads and combined with a black hole quencher 1 (BHQ1) with complementary DNA as the target recognition element. With the presence of cadmium, the cadmium-binding aptamer bound to cadmium specifically and resulted in the release of BHQ1. The free BHQ1 remained in the solution after magnetic separation and quenched the phosphorescence. The phosphorescence intensity was negatively related to the concentration of cadmium. Under optimal conditions, the time-resolved phosphorescence sensor showed a linear response to cadmium concentration within a range from 0.05 to 5 ng mL-1 and with a detection limit of 0.04 ng mL-1. This "on-off" time-resolved phosphorescence sensor was successfully applied for cadmium detection in spring water and clam samples, which provided a rapid and straightforward method.

Recent advances in development of dendritic polymer-based nanomedicines for cancer diagnosis

Dendritic polymers have highly branched three-dimensional architectures, the fourth type apart from linear, cross-linked, and branched one. They possess not only a large number of terminal functional units and interior cavities, but also a low viscosity with weak or no entanglement. These features endow them with great potential in various biomedicine applications, including drug delivery, gene therapy, tissue engineering, immunoassay and bioimaging. Most review articles related to bio-related applications of dendritic polymers focus on their drug or gene delivery, while very few of them are devoted to their function as cancer diagnosis agents, which are essential for cancer treatment. In this review, we will provide comprehensive insights into various dendritic polymer-based cancer diagnosis agents. Their classification and preparation are presented for readers to have a precise understanding of dendritic polymers. On account of physical/chemical properties of dendritic polymers and biological properties of cancer, we will suggest a few design strategies for constructing dendritic polymer-based diagnosis agents, such as active or passive targeting strategies, imaging reporters-incorporating strategies, and/or internal stimuli-responsive degradable/enhanced imaging strategies. Their recent applications in in vitro diagnosis of cancer cells or exosomes and in vivo diagnosis of primary and metastasis tumor sites with the aid of single/multiple imaging modalities will be discussed in great detail. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Diagnostic Tools > in vivo Nanodiagnostics and Imaging Diagnostic Tools > in vitro Nanoparticle-Based Sensing.

Thermoresponsive cationic dendronized copolymers and their corresponding nanogels as smart gene carriers

Thermoresponsive dendronized copolymer nanogels show unique condensation, protection and controlled release of siRNA due to dendritic topology and spherical morphology.

Parallel evolution of polymer chemistry and immunology: Integrating mechanistic biology with materials design

To develop new therapeutics involves the interaction of multiple disciplines to yield safe, functional devices and formulations. Regardless of drug function and potency, administration with controlled timing, dosing, and targeting is required to properly treat or regulate health and disease. Delivery approaches can be optimized through advances in materials science, clinical testing, and basic biology and immunology. Presently, laboratories focused on developing these technologies are composed of, or collaborate with, chemists, biologists, materials scientists, engineers, and physicians to understand the way our body interacts with drug delivery devices, and how to synthesize new, rationally designed materials to improve targeted and controlled drug delivery. In this review, we discuss both device-based and micro/nanoparticle-based materials in the clinic, our biologic understanding of how our immune system interacts with these materials, how this diverse set of immune cells has become a target and variable in drug delivery design, and new directions in polymer chemistry to address these interactions and further our advances in medical therapeutics.

Recent advances in metallopolymer-based drug delivery systems

Metallopolymers (MPs) or metal-containing polymers have shown great potential as new drug delivery systems (DDSs) due to their unique properties, including universal architectures, composition, properties and surface chemistry. Over the past few decades, the exponential growth of many new classes of MPs that deal with these issues has been demonstrated. This review presents and assesses the recent advances and challenges associated with using MPs as DDSs. Among the most widely used MPs for these purposes, metal complexes based on synthetic and natural polymers, coordination polymers, metal-organic frameworks, and metallodendrimers are distinguished. Particular attention is paid to the stimulus- and multistimuli-responsive metallopolymer-based DDSs. Of considerable interest is the use of MPs for combination therapy and multimodal systems. Finally, the problems and future prospects of using metallopolymer-based DDSs are outlined. The bibliography includes articles published over the past five years.

Cyclic RGD-Functionalized and Disulfide-Crosslinked Iodine-Rich Polymersomes as a Robust and Smart Theranostic Agent for Targeted CT Imaging and Chemotherapy of Tumor

There is tremendous interest in integrating CT imaging with chemotherapy; however, reported iodine-based nanosystems such as nanogels and nano-emulsions display typically reduced contrast coefficient, low drug loading and stability, and poor targetability. Here, cRGD-functionalized disulfide-crosslinked iodine-rich polymersomes (cRGD-XIPs) were designed as a novel, robust and smart theranostic agent and investigated for targeted CT imaging and chemotherapy of malignant tumors. Methods: cRGD-XIPs were prepared from co-self-assembly of poly(ethylene glycol)-b-poly(dithiolane trimethylene carbonate-co-iodinated trimethylene carbonate) (PEG-P(DTC-IC)) and cRGD-PEG-P(DTC-IC) block copolymers. In vitro and in vivo CT contrast effect of cRGD-XIPs was studied using α_vβ₃-overexpressing B16 melanoma as a tumor model in comparison with clinical agent iohexol. The therapeutic efficacy of doxorubicin-loaded cRGD-XIPs (cRGD-XIPs-Dox) to B16 melanoma was investigated and compared with XIPs-Dox (non-targeted), cRGD-IPs-Dox (non-crosslinked) and free Dox. Results: cRGD-XIPs were formed with 55.5 wt.% iodine and ca. 90 nm in diameter. cRGD-XIPs-Dox with a Dox loading of 15.3 wt.% bared superior colloidal stability and reduction-responsive drug release. Notably, blank cRGD-XIPs showed a maximum-tolerated dose (MTD) > 400 mg iodine equiv./kg while cRGD-XIPs-Dox had an MTD > 150 mg Dox equiv./kg, ca. 15-fold improvement over free Dox. cRGD-XIPs revealed superior CT contrast effect and achieved 46.5- and 24.0-fold better enhancement of CT imaging of B16 melanoma than iohexol at 4 h following intratumoral and intravenous injection, respectively. cRGD-XIPs-Dox displayed an elimination half-life of 6.5 h and an elevated accumulation of 6.68% ID/g in the tumors. Furthermore, cRGD-XIPs-Dox was significantly more effective than XIPs-Dox and cRGD-XPs-Dox in inhibiting growth of B16 melanoma model. Conclusion: This proof-of-concept study demonstrates that cRGD-XIPs are a robust, non-toxic and smart polymeric theranostic agent that can not only significantly enhance CT imaging of tumors but also mediate efficient tumor-targeted chemotherapy. XIPs offer a unique and safe platform for theranostic polymersomes that pre-select patients using CT imaging prior to targeted chemotherapy with the same system.

Length effects of cylindrical polymer brushes on their in vitro and in vivo properties

Understanding the relationship between the morphology and biological performance of nanomaterials is very important for their biomedical applications. However, most of the published research focused on spherical systems. The biological properties of the anisotropic nanomaterials have not been studied enough. In this study, we synthesized three sets of cylindrical polymer brushes (CPBs) with different lengths (∼34, 60 and 119 nm) by taking advantage of controlled radical polymerization and Cu(i)-catalyzed alkyne-azide click chemistry. These CPBs had one-dimensional wormlike morphology, the same chemical structure and diameter, desirable water solubility, abundant amino groups and narrowly distributed lengths. These characteristics encouraged us to study length effects on their in vitro and in vivo properties. We demonstrated that longer CPBs had higher cellular uptake, lower tissue permeability, shorter blood circulation time, lower tumor accumulation and rapider body clearance than their shorter counterparts. This work might provide important guidance for the design of biomedical nanomaterials.

Therapeutic Potential of Polyamidoamine Dendrimer for Amyloidogenic Transthyretin Amyloidosis

Amyloidogenic transthyretin (ATTR) amyloidosis is caused by a formation of ATTR amyloid fibrils. Because ATTR misfolding triggers the formation of aggregates and amyloid fibrils, which are considered to deposit on the tissues, novel clinically effective therapeutic strategies targeted to those processes are urgently needed. In this study, to discover a new drug candidate for ATTR amyloidosis therapy, we focused on polyamidoamine dendrimer (dendrimer), a 3D-structural nanomaterial, which has a branched cationic polymer repeating polyamidoamine units. Dendrimer (G2) not only inhibited ATTR V30M amyloid fibril formation, but also reduced already formed ATTR V30M amyloid fibrils by reducing β-sheet structure of ATTR V30M protein. Moreover, intravenous administration of dendrimer (G2) reduced TTR deposition in human ATTR V30M transgenic rats. These results indicate that dendrimer (G2) may possess both inhibitory and breaking effects on ATTR V30M amyloid, suggesting that dendrimer has the potential as a dual effective agents against TTR amyloidosis.

Poly(amidoamine) Dendrimer-Coordinated Copper(II) Complexes as a Theranostic Nanoplatform for the Radiotherapy-Enhanced Magnetic Resonance Imaging and Chemotherapy of Tumors and Tumor Metastasis

The development of a powerful nanoplatform to realize the simultaneous therapy and diagnosis of cancer using a similar element for theranostics remains a critical challenge. Herein, we report such a theranostic nanoplatform based on pyridine (Pyr)-functionalized generation 5 (G5) poly(amidoamine) dendrimers complexed with copper(II) (Cu(II)) for radiotherapy-enhanced T₁-weighted magnetic resonance (MR) imaging and the synergistic radio-chemotherapy of both tumors and tumor metastasis. In this study, amine-terminated G5 dendrimers were covalently linked with 2-pyridinecarboxylic acid, acetylated to neutralize their remaining terminal amines, and complexed with Cu(II) through both the internal tertiary amines and the surface Pyr groups to form the G5.NHAc-Pyr/Cu(II) complexes. We show that the complexes are able to inhibit the proliferation of different cancer cell lines with half-maximal inhibitory concentrations ranging from 4 to 10 μM and induce significant cancer cell apoptosis. Due to the presence of Cu(II), the G5.NHAc-Pyr/Cu(II) complexes display an r₁ relaxivity of 0.7024 mM^-1 s^-1, enabling effective in vivo MR imaging of tumor xenografts and lung metastatic nodules. Further, under radiotherapy (RT) conditions, the tumor MR imaging sensitivity can be significantly enhanced, and the G5.NHAc-Pyr/Cu(II) complexes enable the enhanced chemotherapy of both a xenografted tumor model and a blood-vessel metastasis model. With the demonstrated theranostic potential of the dendrimer-Cu(II) nanocomplexes without additional agents or elements for RT-enhanced MR imaging and chemotherapy of tumor and tumor metastasis, this novel Cu(II)-based nanohybrids may hold great promise for the theranostics of different cancer types and metastases.

Dendrimer- and copolymer-based nanoparticles for magnetic resonance cancer theranostics

Cancer theranostics is one of the most important approaches for detecting and treating patients at an early stage. To develop such a technique, accurate detection, specific targeting, and controlled delivery are the key components. Various kinds of nanoparticles have been proposed and demonstrated as potential nanovehicles for cancer theranostics. Among them, polymer-like dendrimers and copolymer-based core-shell nanoparticles could potentially be the best possible choices. At present, magnetic resonance imaging (MRI) is widely used for clinical purposes and is generally considered the most convenient and noninvasive imaging modality. Superparamagnetic iron oxide (SPIO) and gadolinium (Gd)-based dendrimers are the major nanostructures that are currently being investigated as nanovehicles for cancer theranostics using MRI. These structures are capable of specific targeting of tumors as well as controlled drug or gene delivery to tumor sites using pH, temperature, or alternating magnetic field (AMF)-controlled mechanisms. Recently, Gd-based pseudo-porous polymer-dendrimer supramolecular nanoparticles have shown 4-fold higher T1 relaxivity along with highly efficient AMF-guided drug release properties. Core-shell copolymer-based nanovehicles are an equally attractive alternative for designing contrast agents and for delivering anti-cancer drugs. Various copolymer materials could be used as core and shell components to provide biostability, modifiable surface properties, and even adjustable imaging contrast enhancement. Recent advances and challenges in MRI cancer theranostics using dendrimer- and copolymer-based nanovehicles have been summarized in this review article, along with new unpublished research results from our laboratories.

Radioactive (90Y) upconversion nanoparticles conjugated with recombinant targeted toxin for synergistic nanotheranostics of cancer

We report combined therapy using upconversion nanoparticles (UCNP) coupled to two therapeutic agents: beta-emitting radionuclide yttrium-90 (⁹⁰Y) fractionally substituting yttrium in UCNP, and a fragment of the exotoxin A derived from Pseudomonas aeruginosa genetically fused with a targeting designed ankyrin repeat protein (DARPin) specific to HER2 receptors. The resultant hybrid complex UCNP-R-T was tested using human breast adenocarcinoma cells SK-BR-3 overexpressing HER2 receptors and immunodeficient mice, bearing HER2-positive xenograft tumors. The photophysical properties of UCNPs enabled background-free imaging of the UCNP-R-T distribution in cells and animals. Specific binding and uptake of UCNP complexes in SK-BR-3 cells was observed, with separate ⁹⁰Y- and PE40-induced cytotoxic effects characterized by IC₅₀ 140 μg/mL (UCNP-R) and 5.2 μg/mL (UCNP-T), respectively. When both therapeutic agents were combined into UCNP-R-T, the synergetic effect increased markedly, ∼2200-fold, resulting in IC₅₀ = 0.0024 μg/mL. The combined therapy with UCNP-R-T was demonstrated in vivo.

PEI-NIR Heptamethine Cyanine Nanotheranostics for Tumor Targeted Gene Delivery

Polymer-based nanotheranostics are appealing tools for cancer treatment and diagnosis in the fast-growing field of nanomedicine. A straightforward preparation of novel engineered PEI-based nanotheranostics incorporating NIR fluorescence heptamethine cyanine dyes (NIRF-HC) to enable them with tumor targeted gene delivery capabilities is reported. Branched PEI-2 kDa (b2kPEI) is conjugated with IR-780 and IR-783 dyes by both covalent and noncovalent simple preparative methodologies varying their stoichiometry ratio. The as-prepared set of PEI-NIR-HC nanocarriers are assayed in vitro and in vivo to evaluate their gene transfection efficiency, cellular uptake, cytotoxicity, internalization and trafficking mechanisms, subcellular distribution, and tumor specific gene delivery. The results show the validity of the approach particularly for one of the covalent IR783-b2kPEI conjugates that exhibit an enhanced tumor uptake, probably mediated by organic anion transporting peptides, and favorable intracellular transport to the nucleus. The compound behaves as an efficient nanotheranostic transfection agent in NSG mice bearing melanoma G361 xenographs with concomitant imaging signal and gene concentration in the targeted tumor. By this way, advanced nanotheranostics with multifunctional capabilities (gene delivery, tumor-specific targeting, and NIR fluorescence imaging) are generated in which the NIRF-HC dye component accounts for simultaneous targeting and diagnostics, avoiding additional incorporation of additional tumor-specific targeting bioligands.

Star polymer-based unimolecular micelles and their application in bio-imaging and diagnosis

As a novel kind of polymer with covalently linked core-shell structure, star polymers behave in nanostructure in aqueous medium at all concentration range, as unimolecular micelles at high dilution condition and multi-micelle aggregates in other situations. The unique morphologies endow star polymers with excellent stability and functions, making them a promising platform for bio-application. A variety of functions including imaging and therapeutics can be achieved through rational structure design of star polymers, and the existence of plentiful end-groups on shell offers the opportunity for further modification. In the last decades, star polymers have become an attracting platform on fabrication of novel nano-systems for bio-imaging and diagnosis. Focusing on the specific topology and physicochemical properties of star polymers, we have reviewed recent development of star polymer-based unimolecular micelles and their bio-application in imaging and diagnosis. The main content of this review summarizes the synthesis of integrated architecture of star polymers and their self-assembly behavior in aqueous medium, focusing especially on the recent advances on their bio-imaging application and diagnosis use. Finally, we conclude with remarks and give some outlooks for further exploration in this field.

Cyclotriphosphazene core-based dendrimers for biomedical applications: an update on recent advances

This review is focused on the recent use of cyclotriphosphazene-based dendrimers in biomedicine. Since its synthesis for the first time in 1834, cyclotriphosphazene has been an important compound of phosphorus chemistry as a scaffold, and a large number of cyclotriphosphazene derivatives have been synthesized and applied in various fields such as biology, catalysis, fluorescence, nanomaterials, etc. Today, one of the most important uses concerns its biomedical applications. In this review, the recent developments (since 2012) of cyclotriphosphazene for major pharmaceutical applications are highlighted and analyzed.