Polymer Therapeutics: Concepts and Applications

Modification of the Antibiotic, Colistin, with Dextrin Causes Enhanced Cytotoxicity and Triggers Apoptosis in Myeloid Leukemia

Introduction

Acute myeloid leukemia (AML) remains difficult to treat due to its heterogeneity in molecular landscape, epigenetics and cell signaling alterations. Precision medicine is a major goal in AML therapy towards developing agents that can be used to treat patients with different 'subtypes' in combination with current chemotherapies. We have previously developed dextrin-colistin conjugates to combat the rise in multi-drug resistant bacterial infections and overcome dose-limiting nephrotoxicity. Recent evidence of colistin's anticancer activity, mediated through inhibition of intracellular lysine-specific histone demethylase 1 (LSD1/KDM1A), suggests that dextrin-colistin conjugates could be used to treat cancer cells, including AML. This study aimed to evaluate whether dextrin conjugation (which reduces in vivo toxicity and prolongs plasma half-life) could enhance colistin's cytotoxic effects in myeloid leukemia cell lines and compare the intracellular uptake and localization of the free and conjugated antibiotic.

Results

Our results identified a conjugate (containing 8000 g/mol dextrin with 1 mol% succinoylation) that caused significantly increased toxicity in myeloid leukemia cells, compared to free colistin. Dextrin conjugation altered the mechanism of cell death by colistin, from necrosis to caspase 3/7-dependent apoptosis. In contrast, conjugation via a reversible ester linker, instead of an amide, had no effect on the mechanism of the colistin-induced cell death. Live cell confocal microscopy of fluorescently labelled compounds showed both free and dextrin-conjugated colistins were endocytosed and co-localized in lysosomes, and increasing the degree of modification by succinoylation of dextrin significantly reduced colistin internalization.

Discussion

Whilst clinical translation of dextrin-colistin conjugates for the treatment of AML is unlikely due to the potential to promote antimicrobial resistance (AMR) and the relatively high colistin concentrations required for anticancer activity, the ability to potentiate the effectiveness of an anticancer drug by polymer conjugation, while reducing side effects and improving biodistribution of the drug, is very attractive, and this approach warrants further investigation.

Synthesis and Biological Evaluation of Methoxypolyethylene-Glycol-Substituted Abiraterone Derivatives as Potential Antiprostate Cancer Agents

Globally, prostate cancer is the most commonly diagnosed tumor and a cause of death in older men. Abiraterone, an orally administered irreversible CYP17 inhibitor, is employed to treat prostate cancer. However, abiraterone has several clinical limitations, such as poor water solubility, low dissolution rate, low bioavailability, and toxic side effects in the liver and kidney. Therefore, there is a need to identify high-efficiency and low-toxicity water-soluble abiraterone derivatives. In this work, we aimed to design and synthesize a series of abiraterone derivatives by methoxypoly(ethylene glycol) (mPEG) modification. Their antitumor activities and toxicology were analyzed in vitro and in vivo. The most potent compound, 2e, retained the principle of action on the CYP17 enzyme target and significantly improved the abiraterone water solubility, cell permeability, and blood safety. No significant abnormalities were observed in toxicology. mPEG-modification significantly improved abiraterone's antitumor activity and efficiency while reducing the associated toxic effects. The finding will provide a theoretical basis for future clinical application of mPEG-modified abiraterone.

In-situ noncovalent interaction of ammonium ion enabled C-H bond functionalization of polyethylene glycols

The noncovalent interactions of ammonium ion with multidentate oxygen-based host has never been reported as a reacting center in catalytic reactions. In this work, we report a reactivity enhancement process enabled by non-covalent interaction of ammonium ion, achieving the C-H functionalization of polyethylene glycols with acrylates by utilizing photoinduced co-catalysis of iridium and quinuclidine. A broad scope of alkenes can be tolerated without observing significant degradation. Moreover, this cyano-free condition respectively allows the incorporation of bioactive molecules and the PEGylation of dithiothreitol-treated bovine serum albumin, showing great potentials in drug delivery and protein modification. DFT calculations disclose that the formed α-carbon radical adjacent to oxygen-atom is reduced directly by iridium before acrylate addition. And preliminary mechanistic experiments reveal that the noncovalent interaction of PEG chain with the formed quinuclidinium species plays a unique role as a catalytic site by facilitating the proton transfer and ultimately enabling the transformation efficiently.

Polymersomes as Innovative, Stimuli-Responsive Platforms for Cancer Therapy

This review addresses the urgent need for more targeted and less toxic cancer treatments by exploring the potential of multi-responsive polymersomes. These advanced nanocarriers are engineered to deliver drugs precisely to tumor sites by responding to specific stimuli such as pH, temperature, light, hypoxia, and redox conditions, thereby minimizing the side effects associated with traditional chemotherapy. We discuss the design, synthesis, and recent applications of polymersomes, emphasizing their ability to improve therapeutic outcomes through controlled drug release and targeted delivery. Moreover, we highlight the critical areas for future research, including the optimization of polymersome-biological interactions and biocompatibility, to facilitate their clinical adoption. Multi-responsive polymersomes emerge as a promising development in nanomedicine, offering a pathway to safer and more effective cancer treatments.

Synthesis and in vitro antitumor activity of galactosamine-docetaxel conjugates

Docetaxel (DTX) is a semi-synthetic analogue of paclitaxel which has attracted extensive attention in the treatment of cancer. However, the current clinically used DTX formulations display low tumor targeting ability, leading to unsatisfactory therapeutic outcomes with adverse effects, which poses significant challenges to the clinical application. In this study, three galactosamine (Gal) and docetaxel conjugates with different linkers were synthesized, namely DTX-(suc-Gal)2, DTX-(DTDPA-Gal)2, and DTX-(DSeDPA-Gal)2. These three conjugates were characterized by 1H NMR, FT-IR and HRMS. The in vitro drug release study shows that DTX-(DTDPA-Gal)2 and DTX-(DSeDPA-Gal)2 exhibit glutathione (GSH)-responsive drug release and DTX-(DSeDPA-Gal)2 displays higher GSH-responsiveness. The in vitro antitumor activity study shows that DTX-(DTDPA-Gal)2 and DTX-(DSeDPA-Gal)2 exhibit enhanced cytotoxicity, cell apoptosis rate and G2/M phase arrest against HepG2 cells as compared to DTX-(suc-Gal)2, DTX-(DSeDPA-Gal)2 displays the highest cytotoxicity, cell apoptosis rate and G2/M phase arrest among these three conjugates. In addition, DTX-(DSeDPA-Gal)2 exhibits higher selectivity to HepG2 cells as compared to free DTX. The DTX-(DSeDPA-Gal)2 developed in this study has been proven to be an effective DTX conjugate for selective killing hepatoma cells.

Polysaccharide mediated nanodrug delivery: A review

Polysaccharides have drawn a lot of attention due to their potential as carriers for drugs and other bioactive chemicals. In drug delivery systems, natural macromolecules such as polysaccharides are widely utilized as polymers. This utilization extends to various polysaccharides employed in the development of nanoparticles for medicinal administration, with the goal of enhancing therapeutic efficacy while minimizing side effects. This study not only offers an overview of the existing challenges faced by these materials but also provides detailed information on key polysaccharides expertly engineered into nanoparticles. Noteworthy examples include Bael Fruit Gum, Guar Gum, Pectin, Agar, Cellulose, Alginate, Chitin, and Gum Acacia, each selected for their distinctive properties and strategically integrated into nanoparticles. The exploration of these natural macromolecules illuminates their diverse applications and underscores their potential as effective carriers in drug delivery systems. By delving into the unique attributes of each polysaccharide, this review aims to contribute valuable insights to the ongoing advancements in nanomedicine and pharmaceutical technologies. The overarching objective of this review research is to assess the utilization and comprehension of polysaccharides in nanoapplications, further striving to promote their continued integration in contemporary therapeutics and industrial practices.

Modular design of cyclic peptide - polymer conjugate nanotubes for delivery and tunable release of anti-cancer drug compounds

High aspect-ratio nanomaterials have recently emerged as promising drug delivery vehicles due to evidence of strong cellular association and prolonged in vivo circulation times. Cyclic peptide - polymer conjugate nanotubes are excellent candidates due to their elongated morphology, their supramolecular composition and high degree of pliability due to the versatility in manipulating amino acid sequence and polymer type. In this work, we explore the use of a nanotube structure on which a potent anti-cancer drug, camptothecin, is attached alongside hydrophilic or amphiphilic RAFT polymers, which shield the cargo. We show that subtle modifications to the cleavable linker type and polymer architecture have a dramatic influence over the rate of drug release in biological conditions. In vitro studies revealed that multiple cancer cell lines in 2D and 3D models responded effectively to the nanotube treatment, and analogous fluorescently labelled materials revealed key mechanistic information regarding the degree of cellular uptake and intracellular fate. Importantly, the ability to instruct specific drug release profiles indicates a potential for these nanomaterials as vectors which can provide sustained drug concentrations for a maximal therapeutic effect.

Adjuvant Novel Nanocarrier-Based Targeted Therapy for Lung Cancer

Lung cancer has the lowest survival rate due to its late-stage diagnosis, poor prognosis, and intra-tumoral heterogeneity. These factors decrease the effectiveness of treatment. They release chemokines and cytokines from the tumor microenvironment (TME). To improve the effectiveness of treatment, researchers emphasize personalized adjuvant therapies along with conventional ones. Targeted chemotherapeutic drug delivery systems and specific pathway-blocking agents using nanocarriers are a few of them. This study explored the nanocarrier roles and strategies to improve the treatment profile's effectiveness by striving for TME. A biofunctionalized nanocarrier stimulates biosystem interaction, cellular uptake, immune system escape, and vascular changes for penetration into the TME. Inorganic metal compounds scavenge reactive oxygen species (ROS) through their photothermal effect. Stroma, hypoxia, pH, and immunity-modulating agents conjugated or modified nanocarriers co-administered with pathway-blocking or condition-modulating agents can regulate extracellular matrix (ECM), Cancer-associated fibroblasts (CAF),Tyro3, Axl, and Mertk receptors (TAM) regulation, regulatory T-cell (Treg) inhibition, and myeloid-derived suppressor cells (MDSC) inhibition. Again, biomimetic conjugation or the surface modification of nanocarriers using ligands can enhance active targeting efficacy by bypassing the TME. A carrier system with biofunctionalized inorganic metal compounds and organic compound complex-loaded drugs is convenient for NSCLC-targeted therapy.

Lignocellulosic Membranes Grafted with N-Vinylcaprolactam Using Radiation Chemistry: Load and Release Capacity of Vancomycin

Radiation chemistry presents a unique avenue for developing innovative polymeric materials with desirable properties, eliminating the need for chemical initiators, which can be potentially detrimental, especially in sensitive sectors like medicine. In this investigation, we employed a radiation-induced graft polymerization process with N-vinylcaprolactam (NVCL) to modify lignocellulosic membranes derived from Agave salmiana, commonly known as maguey. The membranes underwent thorough characterization employing diverse techniques, including contact angle measurement, degree of swelling, scanning electron microscopy (SEM), atomic force microscopy (AFM), Fourier-transform infrared-attenuated total reflectance spectroscopy (FTIR-ATR), nuclear magnetic resonance (CP-MAS 13C-NMR), X-ray photoelectron spectroscopy (XPS), and uniaxial tensile mechanical tests. The membranes' ability to load and release an antimicrobial glycopeptide drug was assessed, revealing significant enhancements in both drug loading and sustained release. The grafting of PNVCL contributed to prolonged sustained release by decreasing the drug release rate at temperatures above the LCST. The release profiles were analyzed using the Higuchi, Peppas-Sahlin, and Korsmeyer-Peppas models, suggesting a Fickian transport mechanism as indicated by the Korsmeyer-Peppas model.

Distinguishing anti-PEG antibodies by specificity for the PEG terminus using nanoarchitectonics-based antibiofouling cello-oligosaccharide platforms

The conjugation of poly(ethylene glycol) (PEG) to therapeutic proteins or nanoparticles is a widely used pharmaceutical strategy to improve their therapeutic efficacy. However, conjugation can make PEG immunogenic and induce the production of anti-PEG antibodies, which decreases both the therapeutic efficacy after repeated dosing and clinical safety. To address these concerns, it is essential to analyze the binding characteristics of anti-PEG antibodies to PEG. However, distinguishing anti-PEG antibodies is still a difficult task. Herein, we demonstrate the use of antibiofouling cello-oligosaccharide assemblies tethering one-terminal methoxy oligo(ethylene glycol) (OEG) ligands for distinguishing anti-PEG antibodies in a simple manner. The OEG ligand-tethering two-dimensional crystalline cello-oligosaccharide assemblies were stably dispersed in a buffer solution and had antibiofouling properties against nonspecific protein adsorption. These characteristics allowed enzyme-linked immunosorbent assays (ELISAs) to be simply performed by cycles of centrifugation/redispersion of aqueous dispersions of the assemblies. The simple assays revealed that the specific OEG ligand-tethering assemblies could distinguish anti-PEG antibodies to detect a specific antibody that preferentially binds to the methoxy terminus of the PEG chain with 3 repeating ethylene glycol units. Furthermore, quantitative detection of the antibodies was successfully performed with high sensitivity even in the presence of serum. The detectable and quantifiable range of antibody concentrations covered those required clinically. Our findings open a new avenue for analyzing the binding characteristics of anti-PEG antibodies in biological samples.

Reversible Polymer-Protein Functionalization by Stepwise Introduction of Amine-Reactive, Reductive-Responsive Self-Immolative End Groups onto RAFT-Derived Polymers

Many promising therapeutic protein or peptide drug candidates are rapidly excreted from an organism due to their small size or their inherent immunogenicity. One way to counteract these effects is PEGylation, in which the biopolymer is shielded by synthetic polymers exploiting their stealth properties. However, these modifications are often accompanied by a reduction in the biological function of the protein. By using responsive moieties that bridge the polymer to the protein, a reversible character is provided to this type of conjugation. In this regard, the reductive-responsive nature of disulfides can be exploited via self-immolative structures for reversible linkage to aminic lysine residues and the N-terminus on the protein surface. They enable a traceless release of the intact protein without any further modification and thus preserve the protein's bioactivity. In this study, we demonstrate how this chemistry can be made broadly accessible to RAFT-derived water-soluble polymers like poly(N,N-dimethylacrylamide) (pDMA) as a relevant PEG alternative. A terminal reactive imidazole carbamate with an adjacent self-immolative motif was generated in a gradual manner onto the trithiocarbonate chain transfer moiety of the polymer by first substituting it with a disulfide-bridged alcohol and subsequently converting it into an amine reactive imidazole carbamate. Successful synthesis and complete characterization were demonstrated by NMR, size exclusion chromatography, and mass spectrometry. Finally, two model proteins, lysozyme and a therapeutically relevant nanobody, were functionalized with the generated polymer, which was found to be fully reversible under reductive conditions in the presence of free thiols. This strategy has the potential to extend the generation of reversible reductive-responsive polymer-protein hybrids to the broad field of available functional RAFT-derived polymers.

Design of carboxymethylcellulose-conjugated polymeric prodrug micelles for enhanced in vivo performance of docetaxel

Docetaxel (DTX) has become one of the most important cytotoxic drugs to treat cancer; nevertheless, its poor hydrophilicity and non-specific distribution of DTX lead to detrimental side effects. In this article, we devised carboxymethylcellulose (CMC)-conjugated polymeric prodrug micelles (mPEG-CMC-DTX PMs) for DTX delivery. The ester-bonded polymeric prodrug, mPEG-CMC-DTX, was synthesized and exhibited the capacity for self-assembling into polymeric micelles. The CMC is profusely substituted and acetylated to promote the coupling rate of DTX. Covalent binding of DTX and CMC through an ester bond can be hydrolyzed to dissociate the bond under the action of esterase in the tumor. The mPEG-CMC-DTX PMs displayed promoted drug loading (>50 %, wt), commendable stability, and sustained release behavior in vitro. The gradual release of the prodrug amplified the selectivity of cytotoxicity between normal cells and tumor cells, mitigating the systemic toxicity of mPEG-CMC-DTX PMs and enabling dose intensification. Notably, mPEG-CMC-DTX PMs demonstrated a superior antitumor efficacy and low systemic toxicity due to the elevated tolerance dosage (even at 40 mg/kg DTX). In summation, mPEG-CMC-DTX PMs harmonized the antitumor efficacy and toxicity of DTX. In essence, innovative perspectives for the rational design of CMC-conjugated polymeric prodrug micelles for the delivery of potently toxic drugs were proffered.

Tumor-Associated Macrophage Targeting of Nanomedicines in Cancer Therapy

The tumor microenvironment (TME) is pivotal in tumor growth and metastasis, aligning with the "Seed and Soil" theory. Within the TME, tumor-associated macrophages (TAMs) play a central role, profoundly influencing tumor progression. Strategies targeting TAMs have surfaced as potential therapeutic avenues, encompassing interventions to block TAM recruitment, eliminate TAMs, reprogram M2 TAMs, or bolster their phagocytic capabilities via specific pathways. Nanomaterials including inorganic materials, organic materials for small molecules and large molecules stand at the forefront, presenting significant opportunities for precise targeting and modulation of TAMs to enhance therapeutic efficacy in cancer treatment. This review provides an overview of the progress in designing nanoparticles for interacting with and influencing the TAMs as a significant strategy in cancer therapy. This comprehensive review presents the role of TAMs in the TME and various targeting strategies as a promising frontier in the ever-evolving field of cancer therapy. The current trends and challenges associated with TAM-based therapy in cancer are presented.

Unraveling the versatility of human serum albumin - A comprehensive review of its biological significance and therapeutic potential

Human serum albumin (HSA) is a multi-domain macromolecule with diverse ligand binding capability because of its ability to allow allosteric modulation despite being a monomeric protein. Physiologically, HSA act as the primary carrier for various exogenous and endogenous compounds and fatty acids, and alter the pharmacokinetic properties of several drugs. It has antioxidant properties and is utilized therapeutically to improve the drug delivery of pharmacological agents for the treatment of several disorders. The flexibility of albumin in holding various types of drugs coupled with a variety of modifications makes this protein a versatile drug carrier with incalculable potential in therapeutics. This review provides a brief outline of the different structural properties of HSA, and its various binding sites, moreover, an overview of the genetic, biomedical, and allosteric modulation of drugs and drug delivery aspects of HSA is also included, which may be helpful in guiding advanced clinical applications and further research on the therapeutic potential of this extraordinary protein.

Sulfated Polyglycerol-Modified Hydrogels for Binding HSV-1 and RSV

Heparan sulfate (HS) is a highly sulfated polysaccharide on the surface of mammalian cells and in the extracellular matrix and has been found to be important for virus binding and infection. In this work, we designed synthetic hydrogels with viral binding and deactivation activities through the postfunctionalization of an HS-mimicking polyelectrolyte and alkyl chains. Three polyglycerol-based hydrogels were prepared as substrates and postfunctionalized by sulfated linear polyglycerol (lPGS) via thiol-ene click reaction. The viral binding properties were studied using herpes simplex virus type 1 (HSV-1) and respiratory syncytial virus (RSV). The effect of hydrogel types and molecular weight (Mw) of conjugated lPGS on viral binding properties was also assessed, and promising binding activities were observed in all lPGS-functionalized samples. Further coupling of 11 carbons long alkyl chains to the hydrogel revealed virucidal properties caused by destruction of the viral envelope, as shown by atomic force microscopy (AFM) imaging.

Dendritic Glycerol-Cholesterol Amphiphiles as Drug Delivery Systems: A Comparison between Monomeric and Polymeric Structures

The application of micelles as drug delivery systems has gained a great deal of attention as a means to overcome the current several drawbacks present in conventional cancer treatments. In this work, we highlight the comparison of polymeric and monomeric amphiphilic systems with a similar hydrophilic-lipophilic balance (HLB) in terms of their biocompatibility, aggregation behavior in aqueous solution, and potential in solubilizing hydrophobic compounds. The polymeric system consists of non-ionic polymeric amphiphiles synthesized via sequential RAFT polymerization of polyglycerol first-generation [G1] dendron methacrylate and cholesterol methacrylate to obtain poly(G1-polyglycerol dendron methacrylate)-block-poly(cholesterol methacrylate) (pG1MA-b-pCMA). The monomeric system is a polyglycerol second-generation [G2] dendron end-capped to a cholesterol unit. Both amphiphiles form spherical micellar aggregations in aqueous solution, with differences in size and the morphology in which hydrophobic molecules can be encapsulated. The polymeric and monomeric micelles showed a low critical micelle concentration (CMC) of 0.2 and 17 μg/mL, respectively. The results of our cytotoxicity assays showed that the polymeric system has significantly higher cell viability compared to that of the monomeric amphiphiles. The polymeric micelles were implemented as drug delivery systems by encapsulation of the hydrophobic small molecule doxorubicin, achieving a loading capacity of 4%. In summary, the results of this study reveal that using cholesterol as a building block for polymer synthesis is a promising method of preparation for efficient drug delivery systems while improving the cell viability of monomeric cholesterol.

Recent Trends in Macromolecule-Based Approaches for Hair Loss Treatment

Macromolecules are large, complex molecules composed of smaller subunits known as monomers. The four primary categories of macromolecules found in living organisms are carbohydrates, lipids, proteins, and nucleic acids; they also encompass a broad range of natural and synthetic polymers. Recent studies have shown that biologically active macromolecules can help regenerate hair, providing a potential solution for current hair regeneration therapies. This review examines the latest developments in the use of macromolecules for the treatment of hair loss. The fundamental principles of hair follicle (HF) morphogenesis, hair shaft (HS) development, hair cycle regulation, and alopecia have been introduced. Microneedle (MN) and nanoparticle (NP) delivery systems are innovative treatments for hair loss. Additionally, the application of macromolecule-based tissue-engineered scaffolds for the in vitro and in vivo neogenesis of HFs is discussed. Furthermore, a new research direction is explored wherein artificial skin platforms are adopted as a promising screening method for hair loss treatment drugs. Through these multifaceted approaches, promising aspects of macromolecules for future hair loss treatments are identified.

Carboxymethylcellulose based self-healing hydrogel with coupled DOX as Camptothecin loading carrier for synergetic colon cancer treatment

The self-healing hydrogels have important applications in biomedication as drug release carrier. In this research, the Doxorubicin (DOX) was coupled onto oxidized carboxymethylcellulose (CMC) (CMC-Ald) to fabricate self-healing hydrogel with intrinsic antitumor property and loaded with Camptothecin (CPT) for synergetic antitumor treatment. The DOX coupled CMC-Ald (CMC-AD) was reacted with poly(aspartic hydrazide) (PAH) to fabricate injectable self-healing hydrogel. The coupled DOX avoided the burst release of the drug and the 100 % CPT loaded hydrogel could take the advantages of both drugs to enhance the synergetic antitumor therapeutic effect. The in vitro and in vivo results revealed the CPT loaded CMC-AD/PAH hydrogel showed enhanced antitumor property and reduced biotoxicity of the drugs. These properties demonstrate that the CMC-AD/PAH hydrogel has great application prospects in biomedication.

Nano-Biofertilizer Formulations for Agriculture: A Systematic Review on Recent Advances and Prospective Applications

In the twenty-first century, nanotechnology has emerged as a potentially game-changing innovation. Essential minerals are mostly unavailable in modern cropping systems without the application of synthetic fertilizers, which have a serious negative impact on the ecosystem. This review focuses on the coupling of nanoparticles with biofertilizers to function as nano-biofertilizers (NBFs), which may ensure world food security in the face of the rising population. The inoculation of plants with NBFs improves plant development and resistance to stress. Metallic nanoparticles as well as organic components comprising polysaccharide and chitosan may be encapsulated, utilizing microbe-based green synthesis to make NBFs, which circumvents the limitations of conventional chemical fertilizers. The application of NBFs is just getting started, and shows more promise than other approaches for changing conventional farming into high-tech "smart" farming. This study used bibliographic analysis using Web of Science to find relevant papers on "nano biofertilizers", "plants", and "agriculture". These subjects have received a lot of attention in the literature, as shown by the co-citation patterns of these publications. The novel use of nanotechnology in agriculture is explored in this research work, which makes use of the unique characteristics of nanoscale materials to address urgent concerns including nutrient delivery, crop protection, and sustainable farming methods. This study attempts to fill in some of the gaps in our knowledge by discussing the formulation, fabrication, and characterization of NBFs, as well as elucidating the mechanisms by which NBFs interact with plants and how this benefits the ability of the plant to withstand biotic and abiotic stress brought about by climate change. This review also addresses recent developments and future directions in farming using NBF formulations in the field.

Shell-Sheddable Dendritic Polyglycerol Sulfates Loaded with Sunitinib for Inhibition of Tumor Angiogenesis

Induced angiogenesis, a specific hallmark of cancer, plays a vital role in tumor progression and can be targeted by inhibitors like sunitinib. Sunitinib is a small hydrophobic molecule suffering from low bioavailability and a short half-life in the bloodstream. To overcome these drawbacks, suitable drug delivery systems need to be developed. In this work dendritic polyglycerol (dPG), a well-known polymer, was functionalized with a sheddable shell. Therefore, aliphatic chains of different lengths (C₅, C₉, C₁₁) were coupled to dPG through a cleavable ester bond. To restore water solubility and improve tumor targeting, the surface was decorated with sulfate groups. The resulting shell-sheddable dPG sulfates were characterized and evaluated regarding their loading capacity and biocompatibility in cell culture. The nine-carbon chain derivative (dPG-TNS) was selected as the best candidate for further experiments due to its high drug loading capacity (20wt%), and a sustained release in vitro. The cellular biocompatibility of the blank carrier up to 1mg/mL was confirmed after 24h incubation on HeLa cells. Furthermore, the shell-cleavability of dPG-TNS under different physiological conditions was shown in a degradation study over four weeks. The activity of sunitinib-loaded dPG-TNS was demonstrated in a tube formation assay on Human umbilical vein endothelial cells (HUVECs). Our results suggest that the drug-loaded nanocarrier is a promising candidate to be further investigated in tumor treatments, as it shows similar efficacy to free sunitinib while overcoming its limitations.

Impairing Tumor Metabolic Plasticity via a Stable Metal-Phenolic-Based Polymeric Nanomedicine to Suppress Colorectal Cancer

Targeting metabolic vulnerability of tumor cells is a promising anticancer strategy. However, the therapeutic efficacy of existing metabolism-regulating agents is often compromised due to tolerance resulting from tumor metabolic plasticity, as well as their poor bioavailability and tumor-targetability. Inspired by the inhibitive effect of N-ethylmaleimide on the mitochondrial function, a dendronized-polymer-functionalized metal-phenolic nanomedicine (pOEG-b-D-SH@NP) encapsulating maleimide-modified doxorubicin (Mal-DOX) is developed to enable improvement in the overall delivery efficiency and inhibition of the tumor metabolism via multiple pathways. It is observed that Mal-DOX and its derived nanomedicine induces energy depletion of CT26 colorectal cancer cells more efficiently than doxorubicin, and shifts the balance of programmed cell death from apoptosis toward necroptosis. Notably, pOEG-b-D-SH@NP simultaneously inhibits cellular oxidative phosphorylation and glycolysis, thus potently suppressing cancer growth and peritoneal intestinal metastasis in mouse models. Overall, the study provides a promising dendronized-polymer-derived nanoplatform for the treatment of cancers through impairing metabolic plasticity.

Water-Soluble Gd(III)-Porphyrin Complexes Capable of Both Photosensitization and Relaxation Enhancement

With the aim of developing more stable Gd(III)-porphyrin complexes, two types of ligands 1 and 2 with carboxylic acid anchors were synthesized. Due to the N-substituted pyridyl cation attached to the porphyrin core, these porphyrin ligands were highly water-soluble and formed the corresponding Gd(III) chelates, Gd-1 and Gd-2. Gd-1 was sufficiently stable in neutral buffer, presumably due to the preferred conformation of the carboxylate-terminated anchors connected to nitrogen in the meta position of the pyridyl group helping to stabilize Gd(III) complexation by the porphyrin center. ¹H NMRD (nuclear magnetic relaxation dispersion) measurements on Gd-1 revealed high longitudinal water proton relaxivity (r₁ = 21.2 mM^-1 s^-1 at 60 MHz and 25 °C), which originates from slow rotational motion resulting from aggregation in aqueous solution. Under visible light irradiation, Gd-1 showed extensive photoinduced DNA cleavage in line with efficient photoinduced singlet oxygen generation. Cell-based assays revealed no significant dark cytotoxicity of Gd-1, while it showed sufficient photocytotoxicity on cancer cell lines under visible light irradiation. These results indicate the potential of this Gd(III)-porphyrin complex (Gd-1) as a core for the development of bifunctional systems acting as an efficient photodynamic therapy photosensitizer (PDT-PS) with magnetic resonance imaging (MRI) detection capabilities.

Lipid Prodrug Nanoassemblies via Dynamic Covalent Boronates

Prodrug nanoassemblies combine the advantages of prodrug and nanomedicines, offering great potential in targeting the lesion sites and specific on-demand drug release, maximizing the therapeutic performance while minimizing their side effects. However, there is still lacking a facile pathway to prepare the lipid prodrug nanoassemblies (LPNAs). Herein, we report the LPNAs via the dynamic covalent boronate between catechol and boronic acid. The resulting LPNAs possess properties like drug loading in a dynamic covalent manner, charge reversal in an acidic microenvironment, and specific drug release at an acidic and/or oxidative microenvironment. Our methodology enables the encapsulation and delivery of three model drugs: ciprofloxacin, bortezomib, and miconazole. Moreover, the LPNAs are often more efficient in eradicating pathogens or cancer cells than their free counterparts, both in vitro and in vivo. Together, our LPNAs with intriguing properties may boost the development of drug delivery and facilitate their clinical applications.

Controllable C-H Alkylation of Polyethers via Iron Photocatalysis

The efficient conversion of a C-H bond in the polyether chain to other functional groups provides great opportunities for development of novel applications in many research fields. However, this field is quite underdeveloped due to the key challenge on controlling the selectivity of the C-H bond functionalization over the chain cleavage. In this work, we report a controllable C-H bond alkylation of polyethers under mild conditions via photoinduced iron catalysis. The level of functionalization could be controlled by using different amounts of alkenes and various reaction times, while the molecular weight distributions were maintained narrow. A broad scope of electron-deficient alkenes containing nitrile, ester, epoxide, terminal alkynyl, 2,5-dioxotetrafuranyl, and 2,5-dioxopyrrolidinyl groups could be utilized to functionalize the different polyethers with great efficiencies. The potential applications of the modified polyethylene glycols and polyethylene oxides were explored by the preparation of novel hydrogels and solid-state electrolytes with enhancement of lithium ion conductivities. Moreover, the density functional theory calculation disclosed the plausible mechanism and explained the high selectivity for the C-H alkylation.

Medical Imaging Technology and Imaging Agents

Medical imaging is a technology that studies the interaction between human body and irradiations of X-ray, ultrasound, magnetic field, etc. and represents anatomical structures of human organs/tissues with the implication of irradiation attenuation in the form of grayscales. With these medical images, detailed information on health status and disease diagnosis may be judged by clinical physicians to determine an appropriate therapy approach. This chapter will give a systematic introduction on the modalities, classifications, basic principles, and biomedical applications of traditional medical imaging along with the types, construction, and major features of the corresponding contrast agents or imaging probes.

Encapsulins: Structure, Properties, and Biotechnological Applications

In 1994 a new class of prokaryotic compartments was discovered, collectively called "encapsulins" or "nanocompartments". Encapsulin shell protomer proteins self-assemble to form icosahedral structures of various diameters (24-42 nm). Inside of nanocompartments shells, one or several cargo proteins, diverse in their functions, can be encapsulated. In addition, non-native cargo proteins can be loaded into nanocompartments, and shell surfaces can be modified via various compounds, which makes it possible to create targeted drug delivery systems, labels for optical and MRI imaging, and to use encapsulins as bioreactors. This review describes a number of strategies of encapsulins application in various fields of science, including biomedicine and nanobiotechnologies.

Polymeric Chloroquine as an Effective Antimigration Agent in the Treatment of Pancreatic Cancer

Hydroxychloroquine (HCQ) has been the subject of multiple recent preclinical and clinical studies for its beneficial use in the combination treatments of different types of cancers. Polymeric HCQ (PCQ), a macromolecular multivalent version of HCQ, has been shown to be effective in various cancer models both in vitro and in vivo as an inhibitor of cancer cell migration and experimental lung metastasis. Here, we present detailed in vitro studies that show that low concentrations of PCQ can efficiently inhibit cancer cell migration and colony formation orders of magnitude more effectively compared to HCQ. After intraperitoneal administration of PCQ in vivo, high levels of tumor accumulation and penetration are observed, combined with strong antimetastatic activity in an orthotopic pancreatic cancer model. These studies support the idea that PCQ may be effectively used at low doses as an adjuvant in the therapy of pancreatic cancer. In conjunction with previously published literature, these studies further undergird the potential of PCQ as an anticancer agent.

Nanoparticles design considerations to co-deliver nucleic acids and anti-cancer drugs for chemoresistance reversal

Chemoresistance and hence the consequent treatment failure is considerably challenging in clinical cancer therapeutics. The understanding of the genetic variations in chemoresistance acquisition encouraged the use of gene modulatory approaches to restore anti-cancer drug efficacy. Many smart nanoparticles are designed and optimized to mediate combinational therapy between nucleic acid and anti-cancer drugs. This review aims to define a rational design of such co-loaded nanocarriers with the aim of chemoresistance reversal at various cellular levels to improve the therapeutic outcome of anticancer treatment. Going through the principles of therapeutics loading, physicochemical characteristics tuning, and different nanocarrier modifications, also looking at combination effectiveness on chemosensitivity restoration. Up to now, these emerging nanocarriers are in development status but are expected to introduce outstanding outcomes.

Poly(2-oxazoline)s as Stimuli-Responsive Materials for Biomedical Applications: Recent Developments of Polish Scientists

Poly(2-oxazoline)s are the synthetic polymers that are the products of the cationic ring-opening polymerization (CROP) of 2-oxazoline monomers. Due to their beneficial properties, from which biocompatibility, stealth behavior, high functionalization possibilities, low dispersity, stability, nonionic character, and solubility in water and organic solvents should be noted, they have found many applications and gained enormous interest from scientists. Additionally, with high versatility attainable through copolymerization or through post-polymerization modifications, this class of polymeric systems has been widely used as a polymeric platform for novel biomedical applications. The chemistry of polymers significant expanded into biomedical applications, in which polymeric networks can be successfully used in pharmaceutical development for tissue engineering, gene therapies, and also drug delivery systems. On the other hand, there is also a need to create ‘smart’ polymer biomaterials, responsive to the specified factor, that will be sensitive to various environmental stimuli. The commonly used stimuli-responsive biomedical materials are based mostly on temperature-, light-, magnetic-, electric-, and pH-responsive systems. Thus, creating selective and responsive materials that allow personalized treatment is in the interest of the scientific world. This review article focuses on recent discoveries by Polish scientists working in the field of stimuli-responsive poly(2-oxazoline)s, and their work is compared and contrasted with results reported by other world-renowned specialists.

Antibody-drug conjugates: What drives their progress?

Antibody-drug conjugates (ADCs) are on the brink of widespread use for the targeted treatment of cancer. ADCs manage the toxicity of drugs with unacceptable narrow therapeutic windows by guiding highly toxic compounds to the target cells, thereby sparing healthy cells. In this review, we describe approved ADCs and discuss their modes of action, together with medicinal chemical aspects, to evaluate the potential for improvement and to combat tumor-acquired resistance. A recent research focus has centered on the stimulation of immune responses to induce immunogenic cell death and the influence on the tumor microenvironment to enhance bystander effects.

An Updated Overview of Cyclodextrin-Based Drug Delivery Systems for Cancer Therapy

Encompassing a group of complex and heterogeneous diseases, cancer continues to be a challenge for patients and healthcare systems worldwide. Thus, it is of vital importance to develop advanced treatment strategies that could reduce the trends of cancer-associated morbidity and mortality rates. Scientists have focused on creating performant delivery vehicles for anti-cancer agents. Among the possible materials, cyclodextrins (CDs) attracted increasing interest over the past few years, leading to the emergence of promising anti-tumor nanomedicines. Tackling their advantageous chemical structure, ease of modification, natural origin, biocompatibility, low immunogenicity, and commercial availability, researchers investigated CD-based therapeutical formulations against many types of cancer. In this respect, in this paper, we briefly present the properties of interest of CDs for designing performant nanocarriers, further reviewing some of the most recent potential applications of CD-based delivery systems in cancer management.

An Updated Overview of Cyclodextrin-Based Drug Delivery Systems for Cancer Therapy

Encompassing a group of complex and heterogeneous diseases, cancer continues to be a challenge for patients and healthcare systems worldwide. Thus, it is of vital importance to develop advanced treatment strategies that could reduce the trends of cancer-associated morbidity and mortality rates. Scientists have focused on creating performant delivery vehicles for anti-cancer agents. Among the possible materials, cyclodextrins (CDs) attracted increasing interest over the past few years, leading to the emergence of promising anti-tumor nanomedicines. Tackling their advantageous chemical structure, ease of modification, natural origin, biocompatibility, low immunogenicity, and commercial availability, researchers investigated CD-based therapeutical formulations against many types of cancer. In this respect, in this paper, we briefly present the properties of interest of CDs for designing performant nanocarriers, further reviewing some of the most recent potential applications of CD-based delivery systems in cancer management.

Hyaluronic Acid within Self-Assembling Nanoparticles: Endless Possibilities for Targeted Cancer Therapy

Self-assembling nanoparticles (SANPs) based on hyaluronic acid (HA) represent unique tools in cancer therapy because they combine the HA targeting activity towards cancer cells with the advantageous features of the self-assembling nanosystems, i.e., chemical versatility and ease of preparation and scalability. This review describes the key outcomes arising from the combination of HA and SANPs, focusing on nanomaterials where HA and/or HA-derivatives are inserted within the self-assembling nanostructure. We elucidate the different HA derivatization strategies proposed for this scope, as well as the preparation methods used for the fabrication of the delivery device. After showing the biological results in the employed in vivo and in vitro models, we discussed the pros and cons of each nanosystem, opening a discussion on which approach represents the most promising strategy for further investigation and effective therapeutic protocol development.

Changing Fate: Reprogramming Cells via Engineered Nanoscale Delivery Materials

The incorporation of nanotechnology in regenerative medicine is at the nexus of fundamental innovations and early-stage breakthroughs, enabling exciting biomedical advances. One of the most exciting recent developments is the use of nanoscale constructs to influence the fate of cells, which are the basic building blocks of healthy function. Appropriate cell types can be effectively manipulated by direct cell reprogramming; a robust technique to manipulate cellular function and fate, underpinning burgeoning advances in drug delivery systems, regenerative medicine, and disease remodeling. Individual transcription factors, or combinations thereof, can be introduced into cells using both viral and nonviral delivery systems. Existing approaches have inherent limitations. Viral-based tools include issues of viral integration into the genome of the cells, the propensity for uncontrollable silencing, reduced copy potential and cell specificity, and neutralization via the immune response. Current nonviral cell reprogramming tools generally suffer from inferior expression efficiency. Nanomaterials are increasingly being explored to address these challenges and improve the efficacy of both viral and nonviral delivery because of their unique properties such as small size and high surface area. This review presents the state-of-the-art research in cell reprogramming, focused on recent breakthroughs in the deployment of nanomaterials as cell reprogramming delivery tools.

Polymer-drug conjugates: Design principles, emerging synthetic strategies and clinical overview

Adagen, an enzyme replacement treatment for adenosine deaminase deficiency, was the first protein-polymer conjugate to be approved in early 1990s. Post this regulatory approval, numerous polymeric drugs and polymeric nanoparticles have entered the market as advanced or next-generation polymer-based therapeutics, while many others have currently been tested clinically. The polymer conjugation to therapeutic moiety offers several advantages, like enhanced solubilization of drug, controlled release, reduced immunogenicity, and prolonged circulation. The present review intends to highlight considerations in the design of therapeutically effective polymer-drug conjugates (PDCs), including the choice of linker chemistry. The potential synthetic strategies to formulate PDCs have been discussed along with recent advancements in the different types of PDCs, i.e., polymer-small molecular weight drug conjugates, polymer-protein conjugates, and stimuli-responsive PDCs, which are under clinical/preclinical investigation. Current impediments and regulatory hurdles hindering the clinical translation of PDC into effective therapeutic regimens for the amelioration of disease conditions have been addressed.

Red blood cells membrane-derived nanoparticles: Applications and key challenges in their clinical translation

Cellular membrane-derived nanoparticles, particularly of red blood cells (RBCs), represent an emerging class of drug delivery systems. The lack of nucleus and organelles in these cells makes them easy to process and empty out intracellular contents. The empty vesicle membranes can then be either used as a coating on nanoparticles or can be reassembled into a nanovesicle. Engineered RBCs membrane has unique ability to retain its lipid bilayer architecture with host's proteins during top-down approach, thus allowing it to form stable nanoformulations mimicking RBCs stealth properties. In addition, its core-shell structure allows loading of different drug molecules, and its surface chemistry can be manipulated by facile conjugation with ligands on the shell. The remarkable ability of RBCs membrane to fuse with membranes of other cells enables the formation of hybrid nanovesicles. In this review, we highlight the biomedical applications of such vesicles and discuss the potential challenges related to its clinical translation. Although nano-RBCs retain much of the host's proteins, which may give an edge over synthetic nanoparticles in terms of lower immunogenicity, its production at industrial level is more challenging. This review gives the critical analysis of barriers involved in the translation of RBCs-derived nanoparticles from preclinical to clinical level. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies Biology-Inspired Nanomaterials > Lipid-Based Structures Toxicology and Regulatory Issues in Nanomedicine > Regulatory and Policy Issues in Nanomedicine.

Nanoparticles Accumulate in the Female Reproductive System during Ovulation Affecting Cancer Treatment and Fertility

Throughout the female menstrual cycle, physiological changes occur that affect the biodistribution of nanoparticles within the reproductive system. We demonstrate a 2-fold increase in nanoparticle accumulation in murine ovaries and uterus during ovulation, compared to the nonovulatory stage, following intravenous administration. This biodistribution pattern had positive or negative effects when drug-loaded nanoparticles, sized 100 nm or smaller, were used to treat different cancers. For example, treating ovarian cancer with nanomedicines during mouse ovulation resulted in higher drug accumulation in the ovaries, improving therapeutic efficacy. Conversely, treating breast cancer during ovulation, led to reduced therapeutic efficacy, due to enhanced nanoparticle accumulation in the reproductive system rather than at the tumor site. Moreover, chemotherapeutic nanoparticles administered during ovulation increased ovarian toxicity and decreased fertility compared to the free drug. The menstrual cycle should be accounted for when designing and implementing nanomedicines for females.

Evaluation of formation and proportion of secondary structure in γ-polyglutamic acid by terahertz time-domain spectroscopy

The study of secondary structure is essential for understanding peptides and proteins. Here, we measured the terahertz (THz) spectra of γ-polyglutamic acid (γ-PGA) dominated by α-helix and random coil (RC) respectively. The α-helix has two absorption peaks in the THz region, but no absorption peak is observed in the RC conformation. We believe this is because the hydrogen bonding effect leads to a higher orientation in the helix-dominated γ-PGA. At lower pH, the absorption intensity of γ-PGA increases with the induction time. Similar changes were obtained in the Fourier infrared spectroscopy (FTIR). Through the correlation analysis of THz and IR spectroscopy, it is found that the characteristic peak at 1.2 THz can be used as a sensitive indicator of the intermediate conformation of the α-helical structure. In addition, the transformation of α-helix-RC conformation is related to the peak intensity at 1.99 THz (R² = 0.991), which preliminarily indicates that terahertz time-domain spectroscopy (THz-TDS) has the potential to become a new effective method for characterizing and evaluating secondary structure.

Self-Assembled Nanostructures from Amphiphilic Sucrose-Soyates for Solubilizing Hydrophobic Guest Molecules

We studied self-assembly and colloidal properties of poly(ethylene glycol) (pEG) conjugated sucrose soyate polyols (PSSP). These molecular platforms were synthesized by covalently connecting PEGs of different molecular weights (M_n) (12 and 16 ethylene oxide units) to epoxidized sucrose soyate (ESS). The synthesized PSSP products showed amphiphilicity, reduced water surface tension, and exhibited critical Aggregation Concentration (CAC) within the range of 0.3-0.4 mg/mL. We observed that PSSP self-assembles in water in the form of nanoparticles without the need of any cosolvents. These nanoparticles exhibited number-average hydrodynamic diameter of 120 ± 8 nm with a polydispersity index (PDI) of <0.3, and negatively charged surfaces. We also found out that PSSP nanoparticles can encapsulate and homogeneously distribute a hydrophobic model compound, such as a phthalocyanine dye, Solvent Blue-70 (BL-70), on a metal surface. Collectively, our studies explored and demonstrated the possibility of molecular diversification of biobased starting materials to form amphiphilic nanoparticles with industrially relevant colloidal and surface properties.

Polyprodrug Nanomedicines: An Emerging Paradigm for Cancer Therapy

Nanomedicines have the potential to provide advanced therapeutic strategies in combating tumors. Polymer-prodrug-based nanomedicines are particularly attractive in cancer therapies owing to the maximum drug loading, prolonged blood circulation, and reduced premature leakage and side effects in comparison with conventional nanomaterials. However, the difficulty in precisely tuning the composition and drug loading of polymer-drug conjugates leads to batch-to-batch variations of the prodrugs, thus significantly restricting their clinical translation. Polyprodrug nanomedicines inherit the numerous intrinsic advantages of polymer-drug conjugates and exhibit well-controlled composition and drug loading via direct polymerization of therapeutic monomers, representing a promising nanomedicine for clinical tumor therapies. In this review, recent advances in the development of polyprodrug nanomedicines are summarized for tumor elimination. Various types of polyprodrug nanomedicines and the corresponding properties are first summarized. The unique advantages of polyprodrug nanomedicines and their key roles in various tumor therapies are further highlighted. Finally, current challenges and the perspectives on future research of polyprodrug nanomedicines are discussed.

Polyphosphazene-Based Nanocarriers for the Release of Camptothecin and Epirubicin

The design and study of efficient polymer-based drug delivery systems for the controlled release of anticancer drugs is one of the pillars of nanomedicine. The fight against metastatic and invasive cancers demands therapeutic candidates with increased and selective toxicity towards malignant cells, long-term activity and reduced side effects. In this sense, polyphosphazene nanocarriers were synthesized for the sustained release of the anticancer drugs camptothecin (CPT) and epirubicin (EPI). Linear poly(dichloro)phosphazene was modified with lipophilic tocopherol or testosterone glycinate, with antioxidant and antitumor activity, and with hydrophilic Jeffamine M1000 to obtain different polyphosphazene nanocarriers. It allowed us to encapsulate the lipophilic CPT and the more hydrophilic EPI. The encapsulation process was carried out via solvent exchange/precipitation, attaining a 9.2-13.6 wt% of CPT and 0.3-2.4 wt% of EPI. CPT-loaded polyphosphazenes formed 140-200 nm aggregates in simulated body physiological conditions (PBS, pH 7.4), resulting in an 80-100-fold increase of CPT solubility. EPI-loaded polyphosphazenes formed 250 nm aggregates in an aqueous medium. CPT and EPI release (PBS, pH 7.4, 37 °C) was monitored for 202 h, being almost linear during the first 8 h. The slow release of testosterone and tocopherol was also sustained for 150 h in PBS (pH 7.4 and 6.0) at 37 °C. The co-delivery of testosterone or tocopherol and the anticancer drugs from the nanocarriers was expected. Cells of the human breast cancer cell line MCF-7 demonstrated good uptake of anticancer-drug-loaded nanocarriers after 6 h. Similarly, MCF-7 spheroids showed good uptake of the anticancer-drug-loaded aggregates after 72 h. Almost all anticancer-drug-loaded polyphosphazenes exhibited similar or superior toxicity against MCF-7 cells and spheroids when compared to raw anticancer drugs. Additionally, cell-cycle arrest in the G2/M phase was increased in response to the drug-loaded nanocarriers. Almost no toxicity of anticancer-drug-loaded aggregates against primary human lung fibroblasts was observed. Furthermore, the aggregates displayed no hemolytic activity, which is in contrast to the parent anticancer drugs. Consequently, synthesized polyphosphazene-based nanocarriers might be potential nanomedicines for chemotherapy.

pH sensitive water-in-water emulsions based on the pullulan and poly(N,N-dimethylacrylamide) aqueous two-phase system

A novel aqueous two-phase system based on pullulan and poly(N,N-dimethylacrylamide) is presented. Furthermore, it is used for the formation of pH sensitive water-in-water emulsions.

Bioactive Synthetic Polymers

Synthetic polymers are omnipresent in society as textiles and packaging materials, in construction and medicine, among many other important applications. Alternatively, natural polymers play a crucial role in sustaining life and allowing organisms to adapt to their environments by performing key biological functions such as molecular recognition and transmission of genetic information. In general, the synthetic and natural polymer worlds are completely separated due to the inability for synthetic polymers to perform specific biological functions; in some cases, synthetic polymers cause uncontrolled and unwanted biological responses. However, owing to the advancement of synthetic polymerization techniques in recent years, new synthetic polymers have emerged that provide specific biological functions such as targeted molecular recognition of peptides, or present antiviral, anticancer, and antimicrobial activities. In this review, the emergence of this generation of bioactive synthetic polymers and their bioapplications are summarized. Finally, the future opportunities in this area are discussed.