Biomedical application of hyperbranched polymers: Recent Advances and challenges

Preparation and characterization of cellulose fluorescent material: Experiment and simulation

The extensive use of fossil based materials has caused serious pollution problems, the full utilization of biomass resources to prepare high value-added new materials is of great significance for the environmental protection and sustainable social development. For this purpose, this study explored the preparation process and molecular dynamics simulation of cellulose fluorescent materials. Firstly, bacterial cellulose was dissolved in a solution of NaOH and urea at low temperature, followed by a solution blending and hot pressing with hyperbranched polyamide. It was found that the addition of hyperbranched polyamide could effectively filled in the internal pores of cellulose hydrogel, thereby enhancing the fluorescence effects and tensile properties, especially the elongation at break of cellulose materials. The optimal amount of hyperbranched polyamide added was 5 wt%. Molecular dynamics simulation showed that the hydrogen bonds and interaction with cellulose increased as the concentration of hyperbranched polyamide increased.

Polymeric Nanoparticles for Drug Delivery

The recent emergence of nanomedicine has revolutionized the therapeutic landscape and necessitated the creation of more sophisticated drug delivery systems. Polymeric nanoparticles sit at the forefront of numerous promising drug delivery designs, due to their unmatched control over physiochemical properties such as size, shape, architecture, charge, and surface functionality. Furthermore, polymeric nanoparticles have the ability to navigate various biological barriers to precisely target specific sites within the body, encapsulate a diverse range of therapeutic cargo and efficiently release this cargo in response to internal and external stimuli. However, despite these remarkable advantages, the presence of polymeric nanoparticles in wider clinical application is minimal. This review will provide a comprehensive understanding of polymeric nanoparticles as drug delivery vehicles. The biological barriers affecting drug delivery will be outlined first, followed by a comprehensive description of the various nanoparticle designs and preparation methods, beginning with the polymers on which they are based. The review will meticulously explore the current performance of polymeric nanoparticles against a myriad of diseases including cancer, viral and bacterial infections, before finally evaluating the advantages and crucial challenges that will determine their wider clinical potential in the decades to come.

Using RAFT Polymerization Methodologies to Create Branched and Nanogel-Type Copolymers

This review aims to highlight the most recent advances in the field of the synthesis of branched copolymers and nanogels using reversible addition-fragmentation chain transfer (RAFT) polymerization. RAFT polymerization is a reversible deactivation radical polymerization technique (RDRP) that has gained tremendous attention due to its versatility, compatibility with a plethora of functional monomers, and mild polymerization conditions. These parameters lead to final polymers with good control over the molar mass and narrow molar mass distributions. Branched polymers can be defined as the incorporation of secondary polymer chains to a primary backbone, resulting in a wide range of complex macromolecular architectures, like star-shaped, graft, and hyperbranched polymers and nanogels. These subcategories will be discussed in detail in this review in terms of synthesis routes and properties, mainly in solutions.

A Theoretical Investigation of the Polyaddition of an AB2+A2+B4 Monomer Mixture

Hyperbranched polymers (HBPs) are widely applied nowadays as functional materials for biomedicine needs, nonlinear optics, organic semiconductors, etc. One of the effective and promising ways to synthesize HBPs is a polyaddition of AB2+A2+B4 monomers that is generated in the A2+CB2, AA'+B3, A2+B'B2, and A2+C2+B3 systems or using other approaches. It is clear that all the foundational features of HBPs that are manufactured by a polyaddition reaction are defined by the component composition of the monomer mixture. For this reason, we have designed a structural kinetic model of AB2+A2+B4 monomer mixture polyaddition which makes it possible to predict the impact of the monomer mixture's composition on the molecular weight characteristics of hyperbranched polymers (number average (DPn) and weight average (DPw) degree of polymerization), as well as the degree of branching (DB) and gel point (pg). The suggested model also considers the possibility of a positive or negative substitution effect during polyaddition. The change in the macromolecule parameters of HBPs formed by polyaddition of AB2+A2+B4 monomers is described as an infinite system of kinetic equations. The solution for the equation system was found using the method of generating functions. The impact of both the component's composition and the substitution effect during the polyaddition of AB2+A2+B4 monomers on structural and molecular weight HBP characteristics was investigated. The suggested model is fairly versatile; it makes it possible to describe every possible case of polyaddition with various monomer combinations, such as A2+AB2, AB2+B4, AB2, or A2+B4. The influence of each monomer type on the main characteristics of hyperbranched polymers that are obtained by the polyaddition of AB2+A2+B4 monomers has been investigated. Based on the results obtained, an empirical formula was proposed to estimate the pg = pA during the polyaddition of an AB2+A2+B4 monomer mixture: pg = pA = (-0.53([B]0/[A]0)1/2 + 0.78)υAB2 + (1/3)1/2([B]0/[A]0)1/2, where (1/3)1/2([B]0/[A]0)1/2 is the Flory equation for the A2+B4 polyaddition, [A]0 and [B]0 are the A and B group concentration from A2 and B4, respectively, and υAB2 is the mole fraction of the AB2 monomer in the mixture. The equation obtained allows us to accurately predict the pg value, with an AB2 monomer content of up to 80%.

Influence of the linkage between long alkyl tails and cationic groups on membrane activity of nano-sized hyperbranched polyquaterniums

The recurrent emergence of serious pathogens necessitates novel insights and highly efficient antibacterial agents. However, the innate inability of metal ions and reactive oxygen species (ROS) to differentiate between bacteria and mammalian cells presents a challenge, limiting the selectivity crucial for an ideal antimicrobial solution. Herein, we present a systematic exploration involving two variants of nano-sized hyperbranched polyquaterniums (NHBPQs) - one featuring a lengthy alkyl tail linked to the ammonium unit at the N-atom center (NHBPQ-A), and the other in a segregated configuration (NHBPQ-B). The exterior alkyl chain chains act as a barrier to the cationic group's non-specific adsorption due to spatial site resistance, causing NHBPQ-A in broad-spectrum cytotoxicity. Conversely, the distinct molecular configuration of NHBPQ-B in the segregated state affords greater flexibility, allowing the cationic groups to be released and interact non-specifically, finally resulting in selective bactericidal activity. Leveraging this selectivity, the optimized NHBPQ-B exhibits robust anti-infectious performance in a model of methicillin-resistant Staphylococcus aureus (MRSA)-infected wounds. This work establishes a promising avenue for biocompatible NHBPQs, holding significant potential in addressing MRSA infections and ameliorating both genetically encoded and phenotypic antibiotic resistance mechanisms.

Wastewater reuse in agriculture: Prospects and challenges

Sustainable water recycling and wastewater reuse are urgent nowadays considering water scarcity and increased water consumption through human activities. In 2015, United Nations Sustainable Development Goal 6 (UN SDG6) highlighted the necessity of recycling wastewater to guarantee water availability for individuals. Currently, wastewater irrigation (WWI) of crops and agricultural land appears essential. The present work overviews the quality of treated wastewater in terms of soil microbial activities, and discusses challenges and benefits of WWI in line with wastewater reuse in agriculture and aquaculture irrigation. Combined conventional-advanced wastewater treatment processes are specifically deliberated, considering the harmful impacts on human health arising from WWI originating from reuse of contaminated water (salts, organic pollutants, toxic metals, and microbial pathogens i.e., viruses and bacteria). The comprehensive literature survey revealed that, in addition to the increased levels of pathogen and microbial threats to human wellbeing, poorly-treated wastewater results in plant and soil contamination with toxic organic/inorganic chemicals, and microbial pathogens. The impact of long-term emerging pollutants like plastic nanoparticles should also be established in further studies, with the development of standardized analytical techniques for such hazardous chemicals. Likewise, the reliable, long-term and extensive judgment on heavy metals threat to human beings's health should be explored in future investigations.

Study on the color-changing mechanism and law of visual formaldehyde sensing system based on hyperbranched polyamines

This study focuses on addressing the limitations associated with most chemical derivatization methods commonly used for formaldehyde detection. These methods often suffer from prolonged derivative times (≥30 min) and complex procedures, which hinder their ability to meet the requirements of real-time and accurate sensing. In this research, a novel formaldehyde indicator system based on hyperbranched polyamine molecule was developed, and its mechanism and principles of color change were investigated. The findings revealed that hyperbranched polyamine molecule effectively reacts with formaldehyde, leading to a reduction in electron cloud density in the amine group N and subsequently causing a decrease in pH value. This reaction enables the visualization of formaldehyde detection through changes in the indicator spectrum. Moreover, the spectral variation pattern exhibits a strong linear correlation with the formaldehyde concentration when the PAMAM concentration is optimized. The detection limit of this method was determined to be 1.8 ppm. Notably, the reaction between PAMAM and formaldehyde is almost instantaneous, the color change is insensitive to temperature, and the method demonstrates high selectivity. Overall, this research contributes to the advancement of real-time formaldehyde monitoring technology and provides insights for future developments in this field.

Trends in the Synthesis of Polymer Nano- and Microscale Materials for Bio-Related Applications

Polymeric nano- and microscale materials bear significant potential in manifold applications related to biomedicine. This is owed not only to the large chemical diversity of the constituent polymers, but also to the various morphologies these materials can achieve, ranging from simple particles to intricate self-assembled structures. Modern synthetic polymer chemistry permits the tuning of many physicochemical parameters affecting the behavior of polymeric nano- and microscale materials in the biological context. In this Perspective, an overview of the synthetic principles underlying the modern preparation of these materials is provided, aiming to demonstrate how advances in and ingenious implementations of polymer chemistry fuel a range of applications, both present and prospective.

Hydroxyapatite/hyperbranched polyitaconic acid/chitosan composite scaffold for bone tissue engineering

In this study, a promising modified composite scaffold (hydroxyapatite/hyperbranched polyitaconic acid/chitosan) was synthesized for bone tissue engineering. Novel hyperbranched polyitaconic acid was prepared through the polymerization of itaconic acid using reversible addition fragmentation chain transfer using a macro‐RAFT agent. The chemical structure of the prepared hyperbranched polyitaconic acid was characterized by FTIR and 1HNMR and was subsequently embedded into hydroxyapatite/chitosan composite. The obtained modified composite scaffold was evaluated by characterizing its porosity, mechanical properties, bioactivity and cytotoxicity. The results showed that the modified composite scaffold had higher mechanical strength (i.e., 0.56 ± 0.03 MPa) in comparison to chitosan/hydroxyapatite scaffold only (i.e., 0.31 ± 0.01 MPa) and also showed higher bioactivity. In addition, the modified composite scaffold (HAP/HBP‐RAFT‐PI/CS) showed anticancer properties and enhanced human skin fibroblasts proliferation.

Novel Multi-Responsive Hyperbranched Polyelectrolyte Polyplexes as Potential Gene Delivery Vectors

In this work, we investigate the complexation behavior of poly(oligo(ethylene glycol)methyl methacrylate)-co-poly(2-(diisopropylamino)ethyl methacrylate), P(OEGMA-co-DIPAEMA), hyperbranched polyelectrolyte copolymers, synthesized by reversible addition fragmentation chain transfer (RAFT) polymerization, with short-linear DNA molecules. The synthesized hyperbranched copolymers (HBC), having a different chemical composition, are prepared in order to study their ability to bind with a linear nucleic acid at various N/P ratios (amine over phosphate groups). Specifically, the three pH and thermo-responsive P(OEGMA-co-DIPAEMA) hyperbranched copolymers were able to form polyplexes with DNA, with dimensions in the nanoscale. Using several physicochemical methods, such as dynamic and electrophoretic light scattering (DLS, ELS), as well as fluorescence spectroscopy (FS), the complexation process and the properties of formed polyplexes were explored in response to physical and chemical stimuli such as temperature, pH, and ionic strength. The mass and the size of polyplexes are shown to be affected by the hydrophobicity of the copolymer utilized each time, as well as the N/P ratio. Additionally, the stability of polyplexes in the presence of serum proteins is found to be excellent. Finally, the multi-responsive hyperbranched copolymers were evaluated regarding their cytotoxicity via in vitro experiments on HEK 293 non-cancerous cell lines and found to be sufficiently non-toxic. Based on our results, these polyplexes could be useful candidates for gene delivery and related biomedical applications.

(Controlled) Free radical (co)polymerization of multivinyl monomers: strategies, topological structures and biomedical applications

Free radical (co)polymerization (FRP/FRcP) of multivinyl monomers (MVMs) has emerged as a powerful strategy for the synthesis of chemically and topologically complex polymers due to its unique reaction kinetics, which enables the preparation of polymers with multiple functional groups and novel macromolecular structures. However, conventional FRP/FRcP of MVMs inevitably leads to insoluble crosslinked materials. Therefore, the development of advanced strategies for the controlled polymerization of MVMs is essential for the preparation of chemically and topologically complex polymers. In this review, we introduce the gelation mechanism of conventional FRP of MVMs and present the strategies of controlled polymerization of MVMs for the preparation of chemically and topologically complex polymers. We also discuss polymers with unique topologies synthesized by controlled polymerization of MVMs, such as crosslinked networks, (hyper)branched, star, cyclic, and single-chain cyclized/knotted structures. Finally, biomedical applications of various advanced polymeric materials prepared by controlled polymerization of MVMs are highlighted and the challenges is this field are discussed.

Perspectives on development of biomedical polymer materials in artificial intelligence age

Polymer materials are widely used in biomedicine, chemistry and material science, whose traditional preparations are mainly based on experience, intuition and conceptual insight, having been applied to the development of many new materials, but facing great challenges due to the vast design space for biomedical polymers. So far, the best way to solve these problems is to accelerate material design through artificial intelligence, especially machine learning. Herein, this paper will introduce several successful cases, and analyze the latest progress of machine learning in the field of biomedical polymers, then discuss the opportunities of this novel method. In particular, this paper summarizes the material database, open-source determination tools, molecular generation methods and machine learning models that have been used for biopolymer synthesis and property prediction. Overall, machine learning could be more effectively deployed on the material design of biomedical polymers, and it is expected to become an extensive driving force to meet the huge demand for customized designs.

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.

Nanoparticles: Taking a Unique Position in Medicine

The human nature of curiosity, wonder, and ingenuity date back to the age of humankind. In parallel with our history of civilization, interest in scientific approaches to unravel mechanisms underlying natural phenomena has been developing. Recent years have witnessed unprecedented growth in research in the area of pharmaceuticals and medicine. The optimism that nanotechnology (NT) applied to medicine and drugs is taking serious steps to bring about significant advances in diagnosing, treating, and preventing disease-a shift from fantasy to reality. The growing interest in the future medical applications of NT leads to the emergence of a new field for nanomaterials (NMs) and biomedicine. In recent years, NMs have emerged as essential game players in modern medicine, with clinical applications ranging from contrast agents in imaging to carriers for drug and gene delivery into tumors. Indeed, there are instances where nanoparticles (NPs) enable analyses and therapies that cannot be performed otherwise. However, NPs also bring unique environmental and societal challenges, particularly concerning toxicity. Thus, clinical applications of NPs should be revisited, and a deep understanding of the effects of NPs from the pathophysiologic basis of a disease may bring more sophisticated diagnostic opportunities and yield more effective therapies and preventive features. Correspondingly, this review highlights the significant contributions of NPs to modern medicine and drug delivery systems. This study also attempted to glimpse the future impact of NT in medicine and pharmaceuticals.

3D printing of polylactic acid: recent advances and opportunities

Bio-based polymers are a class of polymers made by living organisms, a few of them known and commercialized yet. Due to poor mechanical strength and economic constraints, they have not yet seen the extensive application. Instead, they have been an appropriate candidate for biological applications. Growing consumer knowledge of the environmental effect of polymers generated from petrochemical sources and a worldwide transition away from plastics with a lifespan of hundreds of years has resulted in greater interest in such hitherto unattainable sectors. Bio-based polymers come in various forms, including direct or "drop-in" replacements for their petrochemical counterparts with nearly identical properties or completely novel polymers that were previously unavailable, such as polylactide. Few of these bio-based polymers offer significantly improved technical specifications than their alternatives. Polylactic acid (PLA) has been well known in the last decade as a biodegradable thermoplastic source for use in 3DP by the "fused deposition modeling" method. The PLA market is anticipated to accomplish 5.2 billion US dollars in 2020 for its industrial usage. Conversely, 3DP is one of the emerging technologies with immense economic potential in numerous sectors where PLA is one of the critical options as the polymer source due to its environmentally friendly nature, glossiness, multicolor appearance, and ease of printing. The chemical structure, manufacturing techniques, standard features, and current market situation of PLA were examined in this study. This review looks at the process of 3DP that uses PLA filaments in extrusion-based 3DP technologies in particular. Several recent articles describing 3D-printed PLA items have been highlighted.

Polymeric Dendrimers as Nanocarrier Vectors for Neurotheranostics

Dendrimers are polymers with well-defined 3D branched structures that are vastly utilized in various neurotheranostics and biomedical applications, particularly as nanocarrier vectors. Imaging agents can be loaded into dendrimers to improve the accuracy of diagnostic imaging processes. Likewise, combining pharmaceutical agents and anticancer drugs with dendrimers can enhance their solubility, biocompatibility, and efficiency. Practically, by modifying ligands on the surface of dendrimers, effective therapeutic and diagnostic platforms can be constructed and implemented for targeted delivery. Dendrimer-based nanocarriers also show great potential in gene delivery. Since enzymes can degrade genetic materials during their blood circulation, dendrimers exhibit promising packaging and delivery alternatives, particularly for central nervous system (CNS) treatments. The DNA and RNA encapsulated in dendrimers represented by polyamidoamine that are used for targeted brain delivery, via chemical-structural adjustments and appropriate generation, significantly improve the correlation between transfection efficiency and cytotoxicity. This article reports a comprehensive review of dendrimers' structures, synthesis processes, and biological applications. Recent progress in diagnostic imaging processes and therapeutic applications for cancers and other CNS diseases are presented. Potential challenges and future directions in the development of dendrimers, which provide the theoretical basis for their broader applications in healthcare, are also discussed.

CaZnO-based nanoghosts for the detection of ssDNA, pCRISPR and recombinant SARS-CoV-2 spike antigen and targeted delivery of doxorubicin

Overexpression of proteins/antigens and other gene-related sequences in the bodies could lead to significant mutations and refractory diseases. Detection and identification of assorted trace concentrations of such proteins/antigens and/or gene-related sequences remain challenging, affecting different pathogens and making viruses stronger. Correspondingly, coronavirus (SARS-CoV-2) mutations/alterations and spread could lead to overexpression of ssDNA and the related antigens in the population and brisk activity in gene-editing technologies in the treatment/detection may lead to the presence of pCRISPR in the blood. Therefore, the detection and evaluation of their trace concentrations are of critical importance. CaZnO-based nanoghosts (NGs) were synthesized with the assistance of a high-gravity technique at a 1,800 MHz field, capitalizing on the use of Rosmarinus officinalis leaf extract as the templating agent. A complete chemical, physical and biological investigation revealed that the synthesized NGs presented similar morphological features to the mesenchymal stem cells (MSCs), resulting in excellent biocompatibility, interaction with ssDNA- and/or pCRISPR-surface, through various chemical and physical mechanisms. This comprise the unprecedented synthesis of a fully inorganic nanostructure with behavior that is similar to MSCs. Furthermore, the endowed exceptional ability of inorganic NGs for detective sensing/folding of ssDNA and pCRISPR and recombinant SARS-CoV-2 spike antigen (RSCSA), along with in-situ hydrogen peroxide detection on the HEK-293 and HeLa cell lines, was discerned. On average, they displayed a high drug loading capacity of 55%, and the acceptable internalizations inside the HT-29 cell lines affirmed the anticipated MSCs-like behavior of these inorganic-NGs.

Recent advances in aqueous virus removal technologies

The COVID-19 outbreak has triggered a massive research, but still urgent detection and treatment of this virus seems a public concern. The spread of viruses in aqueous environments underlined efficient virus treatment processes as a hot challenge. This review critically and comprehensively enables identifying and classifying advanced biochemical, membrane-based and disinfection processes for effective treatment of virus-contaminated water and wastewater. Understanding the functions of individual and combined/multi-stage processes in terms of manufacturing and economical parameters makes this contribution a different story from available review papers. Moreover, this review discusses challenges of combining biochemical, membrane and disinfection processes for synergistic treatment of viruses in order to reduce the dissemination of waterborne diseases. Certainly, the combination technologies are proactive in minimizing and restraining the outbreaks of the virus. It emphasizes the importance of health authorities to confront the outbreaks of unknown viruses in the future.

Influence of cationic groups on the antibacterial behavior of cationic nano-sized hyperbranched polymers to enhance bacteria-infected wound healing

With the continuous emergence of drug-resistant pathogens, new strategies with high antibacterial efficacy are urgently needed. Herein, five cationic nano-sized hyperbranched polymers (CNHBPs) with cationic functional groups have been constructed, and their antibacterial mechanism has been studied in detail. CNHBPs bearing secondary ammonium salt groups and long alkyl chains (S₁₂-CNHBP) exhibited weak antibacterial and antibiofilm ability, while CNHBPs bearing quaternary ammonium salt groups and long alkyl chains (Q₁₂-CNHBP) showed the highest antimicrobial and strongest antibiofilm activities. ζ potential and isothermal titration microcalorimetry (ITC) results suggest that the negatively charged surfaces of bacterial cells provided Q₁₂-CNHBP with a higher intrinsic electrostatic driving force for bacterial killing than that with S₁₂-CNHBP. Fluorescent tracing and morphological observations indicate that the bacterial genome might be another antibacterial target for S₁₂-CNHBP in addition to the cell wall and membrane, which are mainly antibacterial targets for Q₁₂-CNHBP, making it less likely to induce bacterial resistance. Surprisingly, Q₁₂-CNHBP exhibited superior in vivo therapeutic efficacy in a mouse wound model of methicillin-resistant Staphylococcus aureus (MRSA) infection with low toxicity during treatment. These advantages and ease of preparation will undoubtedly distinguish Q₁₂-CNHBP as a new class of suitable candidates to combat multidrug-resistant pathogen infections. This study opens up a new avenue for exploiting antibacterial biomaterials to treat infections caused by drug-resistant bacteria.

Degradable polyprodrugs: design and therapeutic efficiency

Prodrugs are developed to increase the therapeutic properties of drugs and reduce their side effects. Polyprodrugs emerged as highly efficient prodrugs produced by the polymerization of one or several drug monomers. Polyprodrugs can be gradually degraded to release therapeutic agents. The complete degradation of polyprodrugs is an important factor to guarantee the successful disposal of the drug delivery system from the body. The degradation of polyprodrugs and release rate of the drugs can be controlled by the type of covalent bonds linking the monomer drug units in the polymer structure. Therefore, various types of polyprodrugs have been developed based on polyesters, polyanhydrides, polycarbonates, polyurethanes, polyamides, polyketals, polymetallodrugs, polyphosphazenes, and polyimines. Furthermore, the presence of stimuli-responsive groups, such as redox-responsive linkages (disulfide, boronate ester, metal-complex, and oxalate), pH-responsive linkages (ester, imine, hydrazone, acetal, orthoester, P-O and P-N), light-responsive (metal-complex, o-nitrophenyl groups) and enzyme-responsive linkages (ester, peptides) allow for a selective degradation of the polymer backbone in targeted tumors. We envision that new strategies providing a more efficient synergistic therapy will be developed by combining polyprodrugs with gene delivery segments and targeting moieties.

MIL-125-based nanocarrier decorated with Palladium complex for targeted drug delivery

The aim of this work was to provide a novel approach to designing and synthesizing a nanocomposite with significant biocompatibility, biodegradability, and stability in biological microenvironments. Hence, the porous ultra-low-density materials, metal–organic frameworks (MOFs), have been considered and the MIL-125(Ti) has been chosen due to its distinctive characteristics such as great biocompatibility and good biodegradability immobilized on the surface of the reduced graphene oxide (rGO). Based on the results, the presence of transition metal complexes next to the drug not only can reinforce the stability of the drug on the structure by preparing π–π interaction between ligands and the drug but also can enhance the efficiency of the drug by preventing the spontaneous release. The effect of utilizing transition metal complex beside drug (Doxorubicin (DOX)) on the drug loading, drug release, and antibacterial activity of prepared nanocomposites on the P. aeruginosa and S. aureus as a model bacterium has been investigated and the results revealed that this theory leads to increasing about 200% in antibacterial activity. In addition, uptake, the release of the drug, and relative cell viabilities (in vitro and in vivo) of prepared nanomaterials and biomaterials have been discussed. Based on collected data, the median size of prepared nanocomposites was 156.2 nm, and their biological stability in PBS and DMEM + 10% FBS was screened and revealed that after 2.880 min, the nanocomposite’s size reached 242.3 and 516 nm respectively. The MTT results demonstrated that immobilizing PdL beside DOX leads to an increase of more than 15% in the cell viability. It is noticeable that the AST:ALT result of prepared nanocomposite was under 1.5.

Secondary Ammonium-Based Hyperbranched Poly(amidoamine) with Excellent Membrane-Active Property for Multidrug-Resistant Bacterial Infection

With the rapid emergence of microbial infections induced by "superbugs", public health and the global economy are threatened by the lack of effective and biocompatible antibacterial agents. Herein, we systematically design a series of secondary ammonium-based hyperbranched poly(amidoamine) (SAHBP) with different alkyl chain lengths for probing high-efficacy antibacterial agents. SAHBP modified with alkyl tails at the hyperbranched core could efficiently kill Escherichia coli and Staphylococcus aureus, two types of clinically important bacteria worldwide. The best SAHBP with 12-carbon-long alkyl tails (SAHBP-12) also showed high activity against problematic multidrug-resistant bacteria, including Pseudomonas aeruginosa and methicillin-resistant S. aureus (MRSA). Based on ζ potential, isothermal titration microcalorimetry (ITC), and membrane integrity assays, it is found that SAHBP-12 could attach to the cell membrane via electrostatic adsorption and hydrophobic interactions, following which the integrity of the bacterial cell wall and the cell membrane is disrupted, resulting in severe cell membrane damage and the leakage of cytoplasmic contents, finally causing bacterial cell death. Impressively, benefiting from excellent membrane-active property, SAHBP-12 exhibited robust therapeutic efficacy in MRSA-infected mice wounds. Moreover, SAHBP-12 also showed excellent biosafety in vitro and in vivo, which undoubtedly distinguished it as a potent weapon in combating the growing threat of problematic multidrug-resistant bacterial infections.

(Nano)platforms in bladder cancer therapy: Challenges and opportunities

Urological cancers are among the most common malignancies around the world. In particular, bladder cancer severely threatens human health due to its aggressive and heterogeneous nature. Various therapeutic modalities have been considered for the treatment of bladder cancer although its prognosis remains unfavorable. It is perceived that treatment of bladder cancer depends on an interdisciplinary approach combining biology and engineering. The nanotechnological approaches have been introduced in the treatment of various cancers, especially bladder cancer. The current review aims to emphasize and highlight possible applications of nanomedicine in eradication of bladder tumor. Nanoparticles can improve efficacy of drugs in bladder cancer therapy through elevating their bioavailability. The potential of genetic tools such as siRNA and miRNA in gene expression regulation can be boosted using nanostructures by facilitating their internalization and accumulation at tumor sites and cells. Nanoparticles can provide photodynamic and photothermal therapy for ROS overgeneration and hyperthermia, respectively, in the suppression of bladder cancer. Furthermore, remodeling of tumor microenvironment and infiltration of immune cells for the purpose of immunotherapy are achieved through cargo-loaded nanocarriers. Nanocarriers are mainly internalized in bladder tumor cells by endocytosis, and proper design of smart nanoparticles such as pH-, redox-, and light-responsive nanocarriers is of importance for targeted tumor therapy. Bladder cancer biomarkers can be detected using nanoparticles for timely diagnosis of patients. Based on their accumulation at the tumor site, they can be employed for tumor imaging. The clinical translation and challenges are also covered in current review.

Conductive Aramid Fibers from Electroless Silver Plating of Crosslinked HPAMAM-Modified PPTA: Preparation and Properties

Conductive aramid (PPTA) fibers are highly needed for making flexible conductive materials, antistatic materials, and electromagnetic shielding materials. In this work, silver-plated conductive PPTA fibers with high conductivity and excellent mechanical properties were prepared by the electroless plating of PPTA fibers modified with crosslinked hyperbranched polyamide-amine (HPAMAM). The crosslinked HPAMAM creates a stable interface between the PPTA fibers and the silver plating. The morphology and physicochemical properties of the modified and the silver-plated fibers were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, atomic force microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and thermogravimetric analysis. Three epoxy crosslinking agents with different chain lengths were used to crosslink HPAMAM, and the effects of HPAMAM concentration, crosslinking agent dosage, and crosslinking time on the resistance of the fibers were studied. The long chain crosslinking agent appears to be beneficial to silver plating. The lowest resistance (0.067 Ω/cm) was attained when HPAMAM was modified by diethylene glycol diglycidyl ether (1:1 molar ratio), and 20 g/L HPAMAM was used to modify the PPTA fibers. The tensile strength of the original PPTA fibers decreased by only 3% or less after silver plating.

Green Polymer Nanocomposites for Skin Tissue Engineering

Fabrication of an appropriate skin scaffold needs to meet several standards related to the mechanical and biological properties. Fully natural/green scaffolds with acceptable biodegradability, biocompatibility, and physiological properties quite often suffer from poor mechanical properties. Therefore, for appropriate skin tissue engineering and to mimic the real functions, we need to use synthetic polymers and/or additives as complements to green polymers. Green nanocomposites (either nanoscale natural macromolecules or biopolymers containing nanoparticles) are a class of scaffolds with acceptable biomedical properties window (drug delivery and cardiac, nerve, bone, cartilage as well as skin tissue engineering), enabling one to achieve the required level of skin regeneration and wound healing. In this review, we have collected, summarized, screened, analyzed, and interpreted the properties of green nanocomposites used in skin tissue engineering and wound dressing. We particularly emphasize the mechanical and biological properties that skin cells need to meet when seeded on the scaffold. In this regard, the latest state of the art studies directed at fabrication of skin tissue and bionanocomposites as well as their mechanistic features are discussed, whereas some unspoken complexities and challenges for future developments are highlighted.

Branched, dendritic, and hyperbranched polymers in liquid biopsy device design

The development of minimally invasive tests for cancer diagnosis and prognosis will aid in the research of new treatments and improve survival rates. Liquid biopsies seek to derive actionable information from tumor material found in routine blood samples. The relative scarcity of tumor material in this complex mixture makes isolating and detecting cancerous material such as proteins, circulating tumor DNA, exosomes, and whole circulating tumor cells a challenge for device engineers. This review describes the chemistry and applications of branched and hyperbranched to improve the performance of liquid biopsy devices. These polymers can improve the performance of a liquid biopsy through several mechanisms. For example, polymers designed to increase the affinity of capture enhance device sensitivity. On the other hand, polymers designed to increase binding avidity or repel nonspecific adsorption enhance device specificity. Branched and hyperbranched polymers can also be used to amplify the signal from small amounts of detected material. The further development of hyperbranched polymers in liquid biopsy applications will enhance device capabilities and help these critical technologies reach the oncology clinic where they are sorely needed. This article is categorized under: Diagnostic Tools > Biosensing Diagnostic Tools > Diagnostic Nanodevices.

Molecular Dynamics Simulations of Essential Oil Ingredients Associated with Hyperbranched Polymer Drug Carriers

Our work concerns the study of four candidate drug compounds of the terpenoid family, found as essential oil ingredients in species of the Greek endemic flora, namely carvacrol, p-cymene, γ-terpinene, and thymol, via the simulation method of molecular dynamics. Aquatic solutions of each compound, as well as a solution of all four together in realistic (experimental) proportions, are simulated at atmospheric pressure and 37 °C using an OPLS force field combined with TIP3P water. As verified, all four compounds exhibit a strong tendency to phase-separate, thereby calling for the use of carrier molecules as aids for the drug to circulate in the blood and enter the cells. Systems of two such carrier molecules, the hyperbranched poly(ethylene imine) (HBPEI) polyelectrolyte and hyperbranched polyglycerol (HPG), are examined in mixtures with carvacrol, the most abundant among the four compounds, at a range of concentrations, as well as with all four compounds present in natural proportions. Although a tendency of the terpenoids to cluster separately persists at high concentrations, promising association effects are observed for all drug–polymer ratios. HBPEI systems tend to form diffuse structures comprising small mixed clusters as well as freely floating polymer and essential oil molecules, a finding attributed to the polymer–polymer electrostatic repulsions, which here are only partially screened by the counterions. On the other hand, the electrically neutral HPG molecules cluster together with essential oil species to form a single nanodroplet. Currently, terpenoid–polymer clusters near lipid bilayer membranes are being studied to determine the propensity of the formed complexes to enter cell membranes.

Biogenetic nanocarriers with enhanced pH stability formed by zein and selectively depolymerized mushroom hyperbranched β-glucans

Hyperbranched polysaccharide from Pleurotus tuber-regium (PTR-HBPS) is a β-glucan with high degree of branching (DB, 0.69) and a molecular weight (Mw) of 31.2 × 10⁵ g/mol with mixed β-1, 4/β-1, 4, 6/β-1, 6 glucosidic linkages. PTR-HBPS was depolymerized by cellulase and β-glucosidase under optimized conditions to form PC (PTR-HBPS depolymerized by cellulase) and PG (PTR-HBPS depolymerized by β-glucosidase) fractions with a minimum Mw of 2.74 × 10⁵ and 3.98 × 10⁵ g/mol, respectively. PC fractions had no significant changes for its primary structure in terms of glycosidic linkages, DB, and triple helical structure, while the DB of PG fractions was reduced to 0.63 with the loss of triple helical structure. Nanoparticles fabricated by PC fractions with zein showed better stability under different pH conditions. Enzymatic depolymerized low Mw β-glucan derived from PTR-HBPS with similar structural characteristics as the native one has potential as nanocarriers for food bioactive substances.

Adsorption and Removal of Mercury(II) by a Crosslinked Hyperbranched Polymer Modified via Sulfhydryl

In this study, the highly crosslinked hyperbranched polyamide-amines (H-PAMAMs) were first prepared via one-pot methods and then modified with thiourea to synthesize a novel adsorbent containing sulfhydryl groups (CHAP-SH), which was used to adsorb Hg(II) ions from aqueous solutions. The adsorption characteristics and mechanism of CHAP-SH for Hg(II) ions were systematically studied. As expected, CHAP-SH exhibited a rapid removal performance toward Hg(II), and the maximum adsorption capacity was 282.74 mg/g at 318 K and pH = 4.5. The whole adsorption behavior could be well described by the pseudo-second-order kinetic model and Langmuir and Redlich-Peterson adsorption isotherm models, which reflected that the adsorption process was mainly monolayer chemisorption. Meanwhile, CHAP-SH had strong selectivity for Hg(II) in the presence of multimetal ions, and it had excellent recoverability after five cycles. In order to further elucidate the adsorption mechanism, the adsorbents before and after adsorption were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis, and energy-dispersive X-ray spectroscopy, and the results showed that the nitrogen-containing, oxygen-containing, and sulfur-containing groups in the adsorbent molecule had synergistic complexation with Hg(II). These results indicated that the adsorbents had great potential in the future treatment of aqueous solutions containing Hg(II).

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.

Facile Synthesis of Cross-linked Hyperbranched Polyamidoamines Dendrimers for Efficient Hg(Ⅱ) Removal From Water

Dendrimers as commonly used metal ions adsorption materials have the advantages of good adsorption performance and high reuse rate, but the high cost limits its extensive use. Compared with dendrimers, hyperbranched dendrimers have similar physical and chemical properties and are more economical. Therefore, hyperbranched dendrimers are more suitable for industrial large-scale adsorption. The hyperbranched polyamidoamine (HPAMAM) gels were prepared by cross-linking hyperbranched polyamidoamine (HPAMAM-ECH-x and HPAMAM-EGDE-x) with different amounts of epichlorohydrin (ECH) and ethylene glycol diglycidyl ether (EGDE), respectively. The as-synthesized adsorbents were characterized by FT-IR, SEM and XPS. The prepared adsorbents were used to adsorb Hg(Ⅱ) in aqueous solution, and the effects of solution pH, contact time, temperature and initial concentration of metal ion on the adsorption capacity were investigated. The effect of solution pH indicated that the optimum condition to Hg(Ⅱ) removing was at pH 5.0. The adsorption kinetic curves of the two kinds of materials were in accordance with the pseudo-second-order model. For the HPAMAM-ECH samples, the adsorption thermodynamic curves fitted the Langmuir model, while for the HPAMAM-EGDE samples, both Langmuir and Freundlich equations fitted well. The maximum adsorption capacity of HPAMAM-ECH-3 obtained from Langmuir model toward Hg(Ⅱ) was 3.36 mmol/g at pH 5.0 and 35°C.

A microfluidic paper-based colorimetric device for the visual detection of uric acid in human urine samples

The monitoring of uric acid (UA) as a clinically relevant toxic biomolecule is of particular importance for the diagnosis of various syndromes and for the monitoring of patients undergoing chemotherapy or radiation therapy. Owing to its speed, low consumption of materials, high sensitivity, convenience, and the easy detection of color changes, colorimetric methods have attracted a lot of attention compared to other methods. The use of nanoparticles has been suggested for the non-enzymatic POC detection of biological molecules such as UA. Here, a sensitive, quantitative, and rapid diagnostic method for UA using silver nanoparticles (AgNPs) is reported. The main purpose of this work is to introduce a suitable tool for future studies based on various types of AgNPs for the on-site detection of clinical samples and biomarkers using portable devices. In the present study, a novel μPCD made to measure UA was used in human urine samples. AgNPs with their peroxidase-like activity led to the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) and a bluish-green color upon the decomposition of hydrogen peroxide to ˙OH. UA also reduced the oxidized TMB. The proposed method showed linear responses from 500 to 10 000 μM (using silver citrate nanoparticles (Ag-Cit)), 50 to 10 000 μM (using Ag NPrs and Au@AgNPs), and 1 to 10 000 μM (using Ag NWs). The lower limits of quantification of the proposed method for the detection of UA using Ag-Cit, Ag nanoprisms, Au@Ag core-shell nanoparticles, and Ag nanowires were 500, 50, 50, and 1 μM, respectively. As a result, the proposed assay system could potentially be utilized to detect UA in human urine samples.