Self-assembled biodegradable amphiphilic PEG–PCL–lPEI triblock copolymers at the borderline between micelles and nanoparticles designed for drug and gene delivery

Hybrid Se/melanin-like nanoparticles as ROS quenchers and inhibitors of amyloid aggregation

Hybrid selenium/melanin-like nanoparticles offer different therapeutic strategies against amyloid aggregation. In this study, novel Se-based nanostructures are synthesized, characterized, and preliminarily employed as modulators of amyloid aggregation. In detail, two types of Se NPs are tested: one containing only Se(0), named Se NPs, and the second hybrid Se/melanin structures, indicated as SeMel NPs. Advanced biophysical and spectroscopic analyses elucidate the structures of NPs and the mechanistic underpinnings of the inhibition of aggregation of two protein fragments employed as amyloid models, Aβ21-40 and NPM1264-277. Both NPs are investigated for their antioxidant and superoxide dismutase (SOD)-like activity, as well as for their colloidal stability through dynamic light scattering (DLS) and ζ-potential measurements. ThT and SEM experiments demonstrate their ability to suppress amyloid aggregation, while far-UV circular dichroism (CD) spectroscopy indicates secondary structure alterations upon nanoparticle interaction, revealing a shift from β-sheet-rich conformations towards α-helical intermediates. Finally, SeMel NPs demonstrate cytocompatibility with SH-SY5Y cells and an effective mitigation of the cytotoxic effects of the amyloid models. These findings position hybrid Se-melanin NPs as promising agents for targeted amyloid therapeutics.

Xanthium-Inspired Microsphere Morphology Depends on the Dual Self-Assembly Behavior of Macromolecules

The self-assembly of macromolecular segments promotes the fabrication of polymer microspheres with multiple morphologies. Inspired by the xanthium shells, A dual-driven self-assembly method have defined that enables the construction of multi-dimensional morphologies on the microsphere surface at emulsion-confined interfaces. The two driving forces are derived from the phase separation caused by the immiscibility of macromolecular segments and the different interactions between chain segments of different hydrophilicity and water molecules. The synergistic effects of these two forces, the xanthium shell structure is constructed on the microsphere surface, enabling the development of increasingly complex superstructure. This scalable approach provides extensive potential for the self-assembly technology of block copolymers with opposite properties.

Unveiling the role of poly(vinyl alcohol) in the production of mucus-penetrating PLGA nanoparticles

Mucosal drug delivery offers a promising non-invasive approach in pharmaceutical sciences but faces challenges from the protective mucus layer on mucosal surfaces, limiting drug absorption. Polymeric nanoparticles (NPs) have emerged as effective carriers, leveraging their small size to enhance mucus penetration and drug absorption. This study investigates polyvinyl alcohol (PVA)'s role in enhancing poly(lactic-co-glycolic acid) (PLGA) NPs for mucosal drug delivery. While PVA is commonly used as an emulsion stabilizer, its impact on NP mucoadhesiveness and mucodiffusivity is often overlooked. We characterized PLGA-based NPs with varying PVA types, employing particle tracking and molecular dynamics to demonstrate PVA's direct interaction with mucin MUC 5B. Our findings show reduced interaction with lower PVA hydrolysis, with particle tracking confirming PVA properties influence mucoadhesion. This study underscores PVA's critical role in optimizing NP efficacy for mucosal drug delivery, offering insights for developing more effective drug delivery systems.

The Art of PEGylation: From Simple Polymer to Sophisticated Drug Delivery System

The development of effective drug delivery systems (DDSs) is important for cancer and infectious disease treatment to overcome low bioavailability, rapid clearance and the toxicity of the therapeutic towards non-targeted healthy tissues. This review discusses how PEGylation, the attachment of poly(ethylene glycol) (PEG) molecules to nanoparticles (NPs), enhances drug pharmacokinetics by creating a "stealth effect". We provide the synthesis methods for several PEG derivatives, their conjugation with NPs, proteins and characterization using modern analytical tools. This paper focuses particularly on covalent conjugation and self-assembly strategies for successful PEGylation and discusses the influence of PEG chain length, density and conformation on drug delivery efficiency. Despite the PEGylation benefits, there are several challenges associated with it, including immunogenicity and reduced therapeutic efficacy due to accelerated blood clearance. Therefore, the balance between PEGylation benefits and its immunogenic risks remains a critical area of investigation.

Exploring precision treatments in immune-mediated inflammatory diseases: Harnessing the infinite potential of nucleic acid delivery

Immune-mediated inflammatory diseases (IMIDs) impose an immeasurable burden on individuals and society. While the conventional use of immunosuppressants and disease-modifying drugs has provided partial relief and control, their inevitable side effects and limited efficacy cast a shadow over finding a cure. Promising nucleic acid drugs have shown the potential to exert precise effects at the molecular level, with different classes of nucleic acids having regulatory functions through varying mechanisms. For the better delivery of nucleic acids, safe and effective viral vectors and non-viral delivery systems (including liposomes, polymers, etc.) have been intensively explored. Herein, after describing a range of nucleic acid categories and vectors, we focus on the application of therapeutic nucleic acid delivery in various IMIDs, including rheumatoid arthritis, inflammatory bowel disease, psoriasis, multiple sclerosis, asthma, ankylosing spondylitis, systemic lupus erythematosus, and uveitis. Molecules implicated in inflammation and immune dysregulation are abnormally expressed in a series of IMIDs, and their meticulous modulation through nucleic acid therapy results in varying degrees of remission and improvement of these diseases. By synthesizing findings centered on specific molecular targets, this review delivers a systematic elucidation and perspective towards advancing and utilization of nucleic acid therapeutics for managing IMIDs.

PEI-based functional materials: Fabrication techniques, properties, and biomedical applications

Cationic polymers have recently attracted considerable interest as research breakthroughs for various industrial and biomedical applications. They are particularly interesting due to their highly positive charges, acceptable physicochemical properties, and ability to undergo further modifications, making them attractive candidates for biomedical applications. Polyethyleneimines (PEIs), as the most extensively utilized polymers, are one of the valuable and prominent classes of polycations. Owing to their flexible polymeric chains, broad molecular weight (MW) distribution, and repetitive structural units, their customization for functional composites is more feasible. The specific beneficial attributes of PEIs could be introduced by purposeful functionalization or modification, long service life, biocompatibility, and distinct geometry. Therefore, PEIs have significant potential in biotechnology, medicine, and bioscience. In this review, we present the advances in PEI-based nanomaterials, their transfection efficiency, and their toxicity over the past few years. Furthermore, the potential and suitability of PEIs for various applications are highlighted and discussed in detail. This review aims to inspire readers to investigate innovative approaches for the design and development of next-generation PEI-based nanomaterials possessing cutting-edge functionalities and appealing characteristics.

Recent Progress in Carrier-Free Nanomedicine for Tumor Phototherapy

Safe and effective strategies are urgently needed to fight against the life-threatening diseases of various cancers. However, traditional therapeutic modalities, such as radiotherapy, chemotherapy and surgery, exhibit suboptimal efficacy for malignant tumors owing to the serious side effects, drug resistance and even relapse. Phototherapies, including photodynamic therapy (PDT) and photothermal therapy (PTT), are emerging therapeutic strategies for localized tumor inhibition, which can produce a large amount of reactive oxygen species (ROS) or elevate the temperature to initiate cell death by non-invasive irradiation. In consideration of the poor bioavailability of phototherapy agents (PTAs), lots of drug delivery systems have been developed to enhance the tumor targeted delivery. Nevertheless, the carriers of drug delivery systems inevitably bring biosafety concerns on account of their metabolism, degradation, and accumulation. Of note, carrier-free nanomedicine attracts great attention for clinical translation with synergistic antitumor effect, which is characterized by high drug loading, simplified synthetic method and good biocompatibility. In this review, the latest advances of phototherapy with various carrier-free nanomedicines are summarized, which may provide a new paradigm for the future development of nanomedicine and tumor precision therapy.

Recent Progress in Nanomaterial-Based Biosensors and Theranostic Nanomedicine for Bladder Cancer

Bladder cancer (BCa) is one of the most expensive and common malignancies in the urinary system due to its high progression and recurrence rate. Although there are various methods, including cystoscopy, biopsy, and cytology, that have become the standard diagnosis methods for BCa, their intrinsic invasive and inaccurate properties need to be overcome. The novel urine cancer biomarkers are assisted by nanomaterials-based biosensors, such as field-effect transistors (FETs) with high sensitivity and specificity, which may provide solutions to these problems. In addition, nanomaterials can be applied for the advancement of next-generation optical imaging techniques and the contrast agents of conventional techniques; for example, magnetic resonance imaging (MRI) for the diagnosis of BCa. Regarding BCa therapy, nanocarriers, including mucoadhesive nanoparticles and other polymeric nanoparticles, successfully overcome the disadvantages of conventional intravesical instillation and improve the efficacy and safety of intravesical chemotherapy for BCa. Aside from chemotherapy, nanomedicine-based novel therapies, including photodynamic therapy (PDT), photothermal therapy (PTT), chemodynamic therapy (CDT), sonodynamic therapy (SDT), and combination therapy, have afforded us new ways to provide BC therapy and hope, which can be translated into the clinic. In addition, nanomotors and the nanomaterials-based solid tumor disassociation strategy provide new ideas for future research. Here, the advances in BCa diagnosis and therapy mentioned above are reviewed in this paper.

Role of thermal and reactive oxygen species-responsive synthetic hydrogels in localized cancer treatment (bibliometric analysis and review)

Cancer is a major pharmaceutical challenge that necessitates improved care.

Nanohydrogels: Advanced Polymeric Nanomaterials in the Era of Nanotechnology for Robust Functionalization and Cumulative Applications

In the era of nanotechnology, the synthesis of nanomaterials for advanced applications has grown enormously. Effective therapeutics and functionalization of effective drugs using nano-vehicles are considered highly productive and selectively necessary. Polymeric nanomaterials have shown their impact and influential role in this process. Polymeric nanomaterials in molecular science are well facilitated due to their low cytotoxic behavior, robust functionalization, and practical approach towards in vitro and in vivo therapeutics. This review highlights a brief discussion on recent techniques used in nanohydrogel designs, biomedical applications, and the applied role of nanohydrogels in the construction of advanced therapeutics. We reviewed recent studies on nanohydrogels for their wide applications in building strategies for advantageously controlled biological applications. The classification of polymers is based on their sources of origin. Nanohydrogel studies are based on their polymeric types and their endorsed utilization for reported applications. Nanotechnology has developed significantly in the past decades. The novel and active role of nano biomaterials with amplified aspects are consistently being studied to minimize the deleterious practices and side effects. Here, we put forth challenges and discuss the outlook regarding the role of nanohydrogels, with future perspectives on delivering constructive strategies and overcoming the critical objectives in nanotherapeutic systems.

Preparation of a sustainable bio-copolymer based on Luffa cylindrica cellulose and poly(ɛ-caprolactone) for bioplastic applications

In this research, a bio-based graft copolymer (LCC-g-PCL) based on the cellulose of Luffa cylindrica (LCC) main chain possessing poly(ɛ-caprolactone) (PCL) pendant groups is synthesized through a grafting from approach via ring-opening polymerization (ROP). For this purpose, LCC, extracted from luffa sponges by combined method, is utilized for ROP of ɛ-caprolactone (ɛ-CL) as a macro-initiator in the presence of stannous octoate as a catalyst. Fourier transform infrared (FT-IR), proton and carbon nuclear magnetic resonance (¹H NMR and ¹³C NMR) spectroscopies are utilized to structurally indicate the success of ROP, while the achieved graft copolymer is analyzed in detail by comparing with LCC and neat PCL in terms of wettability, thermal and degradation behaviors by conducting water contact angle (WCA) measurements, thermogravimetric and differential scanning calorimetry analyses (TGA and DSC) and in vitro both hydrolytic and enzymatic biodegradation tests, respectively. The results of conducted tests show that the incorporation of PCL groups on LCC provide the increasing hydrophobicity. In addition, the degradation behavior of the LCC-g-PCL copolymer is found to be more pronounced under enzymatic medium rather than hydrolytic conditions. It is anticipated from the results that LCC-g-PCL can be a potential eco-friendly material particularly in bioplastic industry.

Pure drug nano-assemblies: A facile carrier-free nanoplatform for efficient cancer therapy

Nanoparticulate drug delivery systems (Nano-DDSs) have emerged as possible solution to the obstacles of anticancer drug delivery. However, the clinical outcomes and translation are restricted by several drawbacks, such as low drug loading, premature drug leakage and carrier-related toxicity. Recently, pure drug nano-assemblies (PDNAs), fabricated by the self-assembly or co-assembly of pure drug molecules, have attracted considerable attention. Their facile and reproducible preparation technique helps to remove the bottleneck of nanomedicines including quality control, scale-up production and clinical translation. Acting as both carriers and cargos, the carrier-free PDNAs have an ultra-high or even 100% drug loading. In addition, combination therapies based on PDNAs could possibly address the most intractable problems in cancer treatment, such as tumor metastasis and drug resistance. In the present review, the latest development of PDNAs for cancer treatment is overviewed. First, PDNAs are classified according to the composition of drug molecules, and the assembly mechanisms are discussed. Furthermore, the co-delivery of PDNAs for combination therapies is summarized, with special focus on the improvement of therapeutic outcomes. Finally, future prospects and challenges of PDNAs for efficient cancer therapy are spotlighted.

Linear ABC amphiphilic triblock copolymers for complexation and protection of dsRNA

We herein report the synthesis and characterisation of linear ABC triblock copolymers, investigation of their self-assembly in aqueous solution, and complexation with and protection of double stranded-RNA (dsRNA).

Biodegradable nanoparticles combining cancer cell targeting and anti-angiogenic activity for synergistic chemotherapy in epithelial cancer

A biodegradable engineered nanoplatform combining anti-angiogenic activity and targeting of cancer cells to improve the anticancer activity of docetaxel (DTX) is here proposed. Indeed, we have developed biodegradable nanoparticles (NPs) of poly(ethylene glycol)-poly(ε-caprolactone), exposing on the surface both folate motifs (Fol) for recognition in cells overexpressing Folate receptor-α (FRα) and the anti-angiogenic hexapeptide aFLT1. NPs showed a size around 100 nm, the exposure of 60% of Fol moieties on the surface, and the ability to entrap DTX and sustain its release with time. NPs were stable in simulated biological fluids and slightly interacted with Fetal Bovine serum, especially in the formulation decorated with Fol and aFLT1. The presence of Fol on NPs did not impair the anti-angiogenic activity of aFLT1, as assessed by in vitro tube formation assay in HUVEC endothelial cells. In both 2D and 3D KB cell cultures in vitro, the cytotoxicity of DTX loaded in NPs was not significantly affected by Fol/aFLT1 double decoration compared to free DTX. Remarkably, NPs distributed differently in 3D multicellular spheroids of FRα-positive KB cancer cells depending on the type of ligand displayed on the surface. In particular, NPs unmodified on the surface were randomly distributed in the spheroid, whereas the presence of Fol promoted the accumulation in the outer rims of the spheroid. Finally, NPs with Fol and aFLT1 gave a uniform distribution throughout the spheroid structure. When tested in zebrafish embryos xenografted with KB cells, NPs displaying Fol/aFLT1 reduced DTX systemic toxicity and inhibited the growth of the tumor mass and associated vasculature synergistically. Overall, nanotechnology offers excellent ground for combining therapeutic concepts in cancer, paving the way to novel multifunctional nanopharmaceuticals decorated with bioactive elements that can significantly improve therapeutic outcomes.

Small-Molecule Prodrug Nanoassemblies: An Emerging Nanoplatform for Anticancer Drug Delivery

The antitumor efficiency and clinical translation of traditional nanomedicines is mainly restricted by low drug loading, complex preparation technology, and potential toxicity caused by the overused carrier materials. In recent decades, small-molecule prodrug nanoassemblies (SMP-NAs), which are formed by the self-assembly of prodrugs themselves, have been widely investigated with distinct advantages of ultrahigh drug-loading and negligible excipients-trigged adverse reaction. Benefited from the simple preparation process, SMP-NAs are widely used for chemotherapy, phototherapy, immunotherapy, and tumor diagnosis. In addition, combination therapy based on the accurate co-delivery behavior of SMP-NAs can effectively address the challenges of tumor heterogeneity and multidrug resistance. Recent trends in SMP-NAs are outlined, and the corresponding self-assembly mechanisms are discussed in detail. Besides, the smart stimuli-responsive SMP-NAs and the combination therapy based on SMP-NAs are summarized, with special emphasis on the structure-function relationships. Finally, the outlooks and potential challenges of SMP-NAs in cancer therapy are highlighted.

Development of poly(ethyleneimine) grafted amphiphilic copolymers: Evaluation of their cytotoxicity and ability to complex DNA

Poly(ethyleneimine) (PEI) is one of the most widely used cationic polymers for gene delivery. The high molecular weight polymer, which is commercially available, is highly efficient but also very cytotoxic. The reduction in charge density by using nonlinear architectures based on low molecular weight (LMW) PEI is a promising approach to produce safer DNA-vectors. Herein, a group of cationic graft copolymers with different composition containing a hydrophobic biocompatible backbone and LMW linear PEI (lPEI) grafts obtained by ring opening polymerization and click chemistry was studied. The self-assembly and DNA complexation behavior of these materials was analyzed by the gel retardation assay, zeta potential measurements, and dynamic light scattering. The copolymers formed positively charged particles in water with average sizes between 270 and 377 nm. After they were added to DNA in serum-free medium, these particles acquired negative/near-neutral charges and increased in size depending on the N/P ratio. All copolymers showed reduced cytotoxicity compared to the 25 kDa lPEI used as reference, but the transfection efficiency was reduced. This result suggested that the cationic segments were too small to fully condense the DNA and promote cellular uptake, even with the use of several grafts and the introduction of hydrophobic domains. The trends found in this research showed that a higher degree of hydrophobicity and a higher grafting density can enhance the interaction between the copolymers and DNA. These trends could direct further structural modifications in the search for effective and safe vectors based on this polycation.

Overview of polyethylene glycol-based materials with a special focus on core-shell particles for drug delivery application

Polyethylene glycols (PEG) are water-soluble nonionic polymeric molecules. PEG and PEG-based materials are used for various important applications such as solvents, adhesives, adsorbents, drug delivery agents, tissue engineering scaffolds, etc. The coating of nanoparticles with PEG forms core-shell nanoparticles. The PEG-based core-shell nanoparticles are synthesized for the development of high-quality drug delivery systems. In the present review, we first explained the basics and various applications of PEGs and PEG-based composites materials and then concentrated on the PEG-based core-shell nanoparticles for biomedical applications specifically their use in drug delivery.

PEGylated cationic nanoassemblies based on triblock copolymers to combine siRNA therapeutics with anticancer drugs

Nowadays, the clinical administration of siRNA therapeutics is still challenging due to the need of safe and efficient delivery carriers. In this context, biodegradable and amphiphilic triblock copolymers (ABC) containing amine-based cationic segments could be a powerful tool for siRNA delivery. Herein, we propose a range of poly(ethylene glycol) (PEG)-poly(2-dimethyl(aminoethyl) methacrylate) (pDMAEMA)-polycaprolactone (PCL) copolymers with different lengths of the blocks and hydrophilic/lipophilic balance to deliver siRNA alone or in association with a conventional anticancer drug. mPEG-pDMAEMA-PCL copolymers were synthesized by a combination of techniques and characterized by NMR analysis, Fourier transform infrared (FTIR) spectroscopy, gel permeation chromatography (GPC) and differential scanning calorimetry (DSC). Copolymers were then employed to prepare NPs through nanoprecipitation. NPs based on copolymers with long PCL chains (SSL-NPs and LLL-NPs) showed the best colloidal properties and a highly stable core-shell structure with a better orientation of the PEG fringe on the surface. Concerning siRNA delivery, SSL-NPs based on copolymers with short PEG and pDMAEMA chains showed optimized ability to complex and then deliver siRNA at the cell level. The strong interaction between the nucleic acid and the cationic pDMAEMA blocks of NPs was then confirmed by release studies that showed a sustained release of siRNA within 48 h. The transfection efficiency of NPs was assessed in human melanoma cells. NPs were complexed with a therapeutic siRNA against TUBB3 (TUB-siRNA). We observed the best results with SSL-NPs, probably due to the higher preserved buffer capacity of the pDMAEMA blocks. Finally, in order to give a proof of concept of a possible application in the combined chemo/gene-therapy of cancer, SSL-NPs complexed with TUB-siRNA were loaded with docetaxel (DTX) and then cytotoxicity was evaluated in the same cell line. The co-delivery of TUB-siRNA into NPs appeared to strongly potentiate the anti-proliferative activity of DTX, thus highlighting the combinatory activity of the NPs.

A structurally precise AgxAu25-x nanocluster based cancer theranostic platform with tri-targeting/in situ O2-generation/aggregation enhanced fluorescence imaging/photothermal-photodynamic therapies

The photothermal and photodynamic performances of structurally precise oil-soluble AgxAu25-x (x ≤ 13) nanoclusters were first explored and they were solubilized into new assemblies to form a versatile cancer theranostic platform with tri-targeting/in situ O2-generation/aggregation enhanced fluorescence imaging/photothermal-photodynamic therapy effects, which will provide an important reference for precision theranostics at the atomic level in future.

CRISPR-dcas9 Optogenetic Nanosystem for the Blue Light-Mediated Treatment of Neovascular Lesions

Vascular endothelial growth factor (VEGF) is the key regulator in neovascular lesions. The anti-VEGF injection is a major way to relieve retinal neovascularization and treat these diseases. However, current anti-VEGF therapeutics show significant drawbacks. The reason is the inability to effectively control its therapeutic effect. Therefore, how to controllably inhibit the VEGF target is a key point for preventing angiogenesis. Here, a CRISPR-dCas9 optogenetic nanosystem was designed for the precise regulation of pathologic neovascularization. This system is composed of a light-controlled regulatory component and transcription inhibition component. They work together to controllably and effectively inhibit the target gene's VEGF. The opto-CRISPR nanosystem achieved precise regulation according to individual differences, whereby the expression and interaction of gene was activated by light. The following representative model laser-induced choroid neovascularization and oxygen-induced retinopathy were taken as examples to verify the effect of this nanosystem. The results showed that the opto-CRISPR nanosystem was more efficacious in the light control group (NV area effectively reduced by 41.54%) than in the dark control group without light treatment. This strategy for the CRISPR-optogenetic gene nanosystem led to the development of approaches for treating severe eye diseases. Besides, any target gene of interest can be designed by merely replacing the guide RNA sequences in this system, which provided a method for light-controlled gene transcriptional repression.

Functionalized polymeric hybrid micelles as an efficient nanotheranostic agent for thrombus imaging and thrombolysis

Pathological thrombosis within a vessel hampers blood flow and is the mainspring of numerous fatal cardiovascular complications. In order to specifically image and dissolve a thrombus, we rationally designed a functionalized polymeric hybrid micelle (PHM) system self-assembled from amphiphilic polycaprolactone-polyethylenimine (PCL-PEI) and polycaprolactone-polyethylene glycol (PCL-PEG). Based on a biological component of thrombi, activated coagulation factor XIII (FXIIIa), which is responsible for fibrin crosslinking, we further developed FXIIIa-targeted near infrared imaging and thrombolytic nanoparticles, termed IR780/FPHM/LK NPs, through chemical conjugation of peptides to the system. In a ferric chloride (FeCl₃)-induced mouse carotid thrombosis model, IR780/FPHM/LK NPs specifically targeted the thrombus and significantly enhanced the photoacoustic signal for an accurate diagnosis. When loaded with the fibrinolytic drug lumbrokinase (LK), FPHM remarkably dissociated the thrombus accompanied by an increase in the d-dimer level, a fibrin degradation product, and alleviation of fatal nonspecific hemorrhagic risk. Given its thrombus-specific imaging along with potent therapeutic activities, IR780/FPHM/LK NPs hold promise for developing nanotheranostic agents in preclinical thrombotic vascular disease models.

Folic Acid/Peptides Modified PLGA-PEI-PEG Polymeric Vectors as Efficient Gene Delivery Vehicles: Synthesis, Characterization and Their Biological Performance

Polymeric vectors are safer alternatives for gene delivery owing to their advantages as compared to viral vectors. To improve the stability and transfection efficiency of poly(lactic-co-glycolic acid) (PLGA)- and poly(ethylenimine) (PEI)-based vectors, poly(ethylene glycol) (PEG), folic acid (FA), arginylglycylaspartic acid (RGD) peptides and isoleucine-lysine-valine-alanine-valine (IKVAV) peptides were employed and PLGA-PEI-PEG-FA and PLGA-PEI-PEG-RGD copolymers were synthesized. PLGA-PEI-PEG-FA/DNA, PLGA-PEI-PEG-RGD/DNA and PLGA-PEI-PEG-RGD/IKVAV/DNA nanocomplexes (NCs) were formed through bulk mixing. The structure and properties, including morphology, particle size, surface charge and DNA encapsulation, of NCs were studied. Robust NCs with spherical shape, uniform size distribution and slightly positive charge were able to completely bind DNA above their respective N/P ratios. The critical N/P ratio for PLGA-PEI-PEG-FA/DNA, PLGA-PEI-PEG-RGD/DNA and PLGA-PEI-PEG-RGD/IKVAV/DNA NCs was identified to be 12:1, 8:1 and 10:1, respectively. The covalent modification of PEI through a combination of biodegradable PLGA, hydrophilic PEG and targeting motifs significantly decreased the cytotoxicity of PEI. The developed NCs showed both N/P ratio and cell type-dependent transfection efficiency. An increase in N/P ratio resulted in increased transfection efficiency, and much improved transfection efficiency of NCs was observed above their respective critical N/P ratios. This study provides a promising means to produce polymeric vectors for gene delivery.

Effect of Mixing Ratio of Oppositely Charged Block Copolymers on Polyion Complex Micelles for In Vivo Application

Self-assembled supramolecular structures based on polyion complex (PIC) formation between oppositely charged polymers are attracting much attention for developing drug delivery systems able to endure harsh in vivo environments. As controlling polymer complexation provides an opportunity for engineering the assemblies, an improved understanding of the PIC formation will allow constructing assemblies with enhanced structural and functional capabilities. Here, we focused on the influence of the mixing charge ratio between block aniomers and catiomers on the physicochemical characteristics and in vivo biological performance of the resulting PIC micelles (PIC/m). Our results showed that by changing the mixing charge ratio, the structural state of the core was altered despite the sizes of PIC/m remaining almost the same. These structural variations greatly affected the stability of the PIC/m in the bloodstream after intravenous injection and determined their biodistribution.

Effects of Polymer 3D Architecture, Size, and Chemistry on Biological Transport and Drug Delivery In Vitro and in Orthotopic Triple Negative Breast Cancer Models

The size, shape, and underlying chemistries of drug delivery particles are key parameters which govern their ultimate performance in vivo. Responsive particles are desirable for triggered drug delivery, achievable through architecture change and biodegradation to control in vivo fate. Here, polymeric materials are synthesized with linear, hyperbranched, star, and micellar-like architectures based on 2-hydroxypropyl methacrylamide (HPMA), and the effects of 3D architecture and redox-responsive biodegradation on biological transport are investigated. Variations in "stealth" behavior between the materials are quantified in vitro and in vivo, whereby reduction-responsive hyperbranched polymers most successfully avoid accumulation within the liver, and none of the materials target the spleen or lungs. Functionalization of selected architectures with doxorubicin (DOX) demonstrates enhanced efficacy over the free drug in 2D and 3D in vitro models, and enhanced efficacy in vivo in a highly aggressive orthotopic breast cancer model when dosed over schedules accounting for the biodistribution of the carriers. These data show it is possible to direct materials of the same chemistries into different cellular and physiological regions via modulation of their 3D architectures, and thus the work overall provides valuable new insight into how nanoparticle architecture and programmed degradation can be tailored to elicit specific biological responses for drug delivery.

Surface-modified polymeric nanoparticles for drug delivery to cancer cells

INTRODUCTION

The utilization of polymeric nanoparticles, as drug payloads, has been extensively prevailed in cancer therapy. However, the precise distribution of these nanocarriers is restrained by various physiological and cellular obstacles. Nanoparticles must avoid nonspecific interactions with healthy cells and in vivo compartments to circumvent these barriers. Since in vivo interactions of nanoparticles are mainly dependent on surface properties of nanoparticles, efficient control on surface constituents is necessary for the determination of nanoparticles' fate in the body.

AREAS COVERED

In this review, the surface-modified polymeric nanoparticles and their utilization in cancer treatment were elaborated. First, the interaction of nanoparticles with numerous in vivo barriers was highlighted. Second, different strategies to overcome these obstacles were described. Third, some inspiring examples of surface-modified nanoparticles were presented. Later, fabrication and characterization methods of surface-modified nanoparticles were discussed. Finally, the applications of these nanoparticles in different routes of treatments were explored.

EXPERT OPINION

Surface modification of anticancer drug-loaded polymeric nanoparticles can enhance the efficacy, selective targeting, and biodistribution of the anticancer drug at the tumor site.

Artemisinin Loaded mPEG-PCL Nanoparticle Based Photosensitive Gelatin Methacrylate Hydrogels for the Treatment of Gentamicin Induced Hearing Loss

OBJECTIVE

Artemisinin (ART) is a natural anti-malarial sesquiterpene lactone which has the ability to treat and activate the CLRN1 pathway to play a pivotal role in hearing loss and hair cell function. To investigate the therapeutic effect of ART in hearing loss induced by gentamicin (GM), an ART-loaded poly(ethylene glycol)-b-poly(ε-caprolactone) mPEG-PCL nanoparticle-based photosensitive hydrogel was developed and tested in this study.

MATERIALS AND METHODS

Artemisinin-loaded mPEG-PCL nanoparticles (mPEG-PCL-ART-NPs) were prepared by a double emulsion method and the formulation was optimized by an orthogonal experimental design. The particle size, zeta potential, morphology and in vitro dissolution of the mPEG-PCL-ART-NPs were well characterized. Biocompatibility of the mPEG-PCL-ART-NPs were tested on HeLa cells with an MTT assay. The photo-crosslinkable biodegradable gelatin methacrylate (GelMA) hydrogel was prepared and its physicochemical properties (such as substitution, photocrosslinking efficiency, cell viability morphology, mechanical and swelling properties) were evaluated. Finally, mPEG-PCL-ART-FITC-NPs, loaded mPEG-PCL-ART-NPs, and loaded mPEG-PCL-ART-NPs-GelMA hydrogels were fabricated and a GM toxicity-induced guinea pig ear damage model was established to determine the effectiveness of the materials on returning auditory function and cochlea pathomorphology.

RESULTS

The zeta potential of the mPEG-PCL-ART-NPs was about -38.64 ± 0.21 mV and the average size was 167.51 ± 1.87 nm with an encapsulation efficacy of 81.7 ± 1.46%. In vitro release studies showed that the mPEG-PCL-ART-NPs possessed a sustained-release effect and the MTT experiments showed good biocompatibility properties of the drug-loaded nanoparticles. The results indicated that the 5% GelMA with MA-4% hydrogel had a better crosslinking density and 3D structure for drug loading and drug delivery than controls. Skin penetration results showed that the mPEG-PCL-ART-NPs increased adhesive capacity and avoided fast diffusion in the skin. Most importantly, auditory brainstem response results indicated that the mPEG-PCL-ART-NPs-GelMA hydrogel alleviated hearing loss induced by GM.

CONCLUSION

These results suggested that the presently fabricated mPEG-PCL-ART-NPs-GelMA hydrogels are promising formulations for the treatment of hearing loss induced by GM and lay the foundation for further clinical research of inner ear induction therapy.

Co-delivery of gemcitabine prodrug along with anti NF-κB siRNA by tri-layer micelles can increase cytotoxicity, uptake and accumulation of the system in the cancers

Combination treatment based on gene and chemotherapy is a promising strategy for effective cancer treatment due to the limited therapeutic efficacy of anticancer drugs. Dual functional polymeric micelles (PMs) have been emerged as potent nanocarriers for combinational cancer therapy. In the present study, the potential of tri-layer PMs loaded with anti-nuclear factor-κB (NF-κB) siRNA and 4-(N)-stearoyl gemcitabine (GemC18) has been investigated for cancer treatment. PMs with different core hydrophobicity were prepared by using poly(ε-caprolactone), polyethyleneimine and polyethylene glycol (PCL-PEI-PEG) copolymers and evaluated. The results revealed that GemC18-loaded PMs were significantly more cytotoxic than free drug on breast and pancreatic cancer cells. However, the cytotoxicity of drug loaded micelles was decreased by increasing the micellar core hydrophobicity because of decreasing drug release rate. Moreover, siRNA loaded PMs could considerably inhibit NF-κB expression. PMs loaded with both GemC18 and siRNA exhibited higher capability to induce apoptosis and inhibit migration of both cells. PMs with the most hydrophobic core indicated higher tumor accumulation efficiency via in-vivo imaging study. In conclusion, the prepared PMs hold a promise as an attractive dual functional delivery system for an effective cancer therapy.

Advances in PEG-based ABC terpolymers and their applications

ABC terpolymers are a class of very important polymers because of their expansive molecular topologies and extensive architectures. As block A, poly(ethylene glycol) (PEG) is one of the most principal categories owing to good biocompatibility and wide commercial availability. More importantly, the synthetic approaches of ABC terpolymers using PEG as a macroinitiator are facile and varied. PEG-based ABC terpolymers from design and synthesis to applications are highlighted in this review. Linear, 3-miktoarm, and cyclic polymers as the architecture are separated. The synthetic approaches of PEG-based ABC terpolymers mainly include the sequential polymerization or coupling of polymers. PEG-based ABC terpolymers have wide applications in the fields of drug carriers, gene vectors, templates for the fabrication of inorganic hollow nanospheres, and stabilizers of metal nanoparticles.

Interfacial properties and micellization of triblock poly(ethylene glycol)-poly(ε-caprolactone)-polyethyleneimine copolymers

This study aimed to explore the link between block copolymers' interfacial properties and nanoscale carrier formation and found out the influence of length ratio on these characters to optimize drug delivery system. A library of diblock copolymers of PEG-PCL and triblock copolymers with additional PEI (PEG-PCL-PEI) were synthesized. Subsequently, a systematic isothermal investigation was performed to explore molecular arrangements of copolymers at air/water interface. Then, structural properties and drug encapsulation in self-assembly were investigated with DLS, SLS and TEM. We found the additional hydrogen bond in the PEG-PCL-PEI contributes to film stability upon the hydrophobic interaction compared with PEG-PCL. PEG-PCL-PEI assemble into smaller micelle-like (such as PEG-PCL4006-PEI) or particle-like structure (such as PEG-PCL8636-PEI) determined by their hydrophilic and hydrophobic block ratio. The distinct structural architectures of copolymer are consistent between interface and self-assembly. Despite the disparity of constituent ratio, we discovered the arrangement of both chains guarantees balanced hydrophilic-hydrophobic ratio in self-assembly to form stable construction. Meanwhile, the structural differences were found to have significant influence on model drugs incorporation including docetaxel and siRNA. Taken together, these findings indicate the correlation between molecular arrangement and self-assembly and inspire us to tune block compositions to achieve desired nanostructure and drug loading.

Nanoparticles decorated with folate based on a site-selective αCD-rotaxanated PEG-b-PCL copolymer for targeted cancer therapy

NPs fabricated from a mixture of PEG-b-PCL and selectively rotaxanated Fol-PEG(αCD)-PCL showed internalisation in KB cells through an active targeting mechanism.

Synthesis of novel polyethers with abundant reactive sites and diverse skeletons based on the ring-opening reaction of D–A cyclopropanes

Based on the ring-opening reaction of D–A cyclopropanes, a facile synthesis of novel polyethers is developed with molecular weights up to 17.7 kg mol⁻¹.

Polymeric Micelles Loading Proteins through Concurrent Ion Complexation and pH-Cleavable Covalent Bonding for In Vivo Delivery

Protein drugs have great potential as targeted therapies, yet their application suffers from several drawbacks, such as instability, short half-life, and adverse immune responses. Thus, protein delivery approaches based on stimuli-responsive nanocarriers can provide effective strategies for selectively enhancing the availability and activation of proteins in targeted tissues. Herein, polymeric micelles with the ability of encapsulating proteins are developed via concurrent ion complexation and pH-cleavable covalent bonding between proteins and block copolymers directed to pH-triggered release of the protein payload. Carboxydimethylmaleic anhydride (CDM) is selected as the pH-sensitive moiety, since the CDMamide bond is stable at physiological pH (pH 7.4), while it cleaves at pH 6.5, that is, the pathophysiological pH of tumors and inflammatory tissues. By using poly(ethylene glycol)-poly(l-lysine) block copolymers having 45% CDM addition, different proteins with various sizes and isoelectric points are loaded successfully. By using myoglobin-loaded micelles (myo/m) as a model, the stability of the micelles in physiological conditions and the dissociation and release of functional myoglobin at pH 6.5 are successfully confirmed. Moreover, myo/m shows extended half-life in blood compared to free myoglobin and micelles assembled solely by polyion complex, indicating the potential of this system for in vivo delivery of proteins.

A Polycationic Brush Mediated Co-Delivery of Doxorubicin and Gene for Combination Therapy

The combination of drug and gene strategies for cancer therapy, has exhibited greater effectiveness than drug or gene therapy alone. In this paper, a coil-comb shaped polycationic brush was used as a multifunctional carrier for co-delivery of drug and gene. The side chains of the comb block of the brush were composed of cyclodextrin (CD)-containing cationic star polymers, with a super-high density of positive charge. Doxorubicin (DOX) could be loaded into the cavity of CD polymers to form DOX-loaded nanoparticles (DOX-NPs) and the p53 gene could be subsequently condensed by DOX-NPs. The obtained DOX-NPs/pDNA complexes were less than 150 nm in size, and so could transport DOX and the gene into the same cell. The complexes performed well with regards to their transfection efficiency on MCF-7 cancer cells. As a result, enhanced cell growth inhibition, with decreased DOX dosage was achieved due to the synergistic effect of co-delivery of DOX and the p53 gene. This finding provides an efficient approach for the development of a co-delivery system in combination therapy.

Structural exploration of hydrophobic core in polycationic micelles for improving siRNA delivery efficiency and cell viability

Improving siRNA delivery efficiency often encounters a dilemma with poor or decreased biocompatibility for polycationic micelles.

Puerarin-loaded PEG-PE micelles with enhanced anti-apoptotic effect and better pharmacokinetic profile

Puerarin (PUE) is the most abundant isoflavonoid in kudzu root. It is widely used as a therapeutic agent for the treatment of cardiovascular diseases. However, the short elimination half-life, poor-bioavailability, and acute intravascular hemolysis of PUE are the main obstacles to its widespread clinical applications. Whereas PEG-PE micelles possess the ability to release medicine slowly, enhance the cellular uptake of drugs and improve their biocompatibility. Therefore, it was aim to fabricate puerarin-loaded PEG-PE (PUE@PEG-PE) micelles to improve the pharmaceutical properties of drugs. It can be observed from the TEM images that PUE@PEG-PE micelles appeared obvious core-shell structure and remained well-dispersed without aggregation and adhesion. PUE was successfully embedded in the core of PEG-PE micelles, which was confirmed by FT-IR and ¹H NMR spectra. In vitro studies showed that PUE@PEG-PE micelles exhibited a sustained release behavior in pH 7.4 PBS buffer and decreased hemolysis rate of PUE. Compared with PUE, PUE@PEG-PE micelles showed a 3.2-fold increase in the half-life of PUE and a 1.58-fold increase in bioavailability. In addition, the PUE@PEG-PE micelles exerted enhanced protective effect against isoprenaline-induced H9c2 cells apoptosis compared with PUE, as evident by decreased percentage of Hoechst-positive cells, Caspase 3 activity, Bax expression, and increased Bcl-2 expression. Notably, the PEG-PE micelles exhibited favorable cellular uptake efficiency on H9c2 cells, and this may account for their enhanced anti-apoptotic effect of the incorporated drug. Altogether, the PUE@PEG-PE micelles were not only able to control the drug release but also offered promise to enhance the pharmacokinetic and pharmacodynamic potential of PUE.

A highly antibacterial polymeric hybrid micelle with efficiently targeted anticancer siRNA delivery and anti-infection in vitro/in vivo

Most of the diseases such as tumors are usually accompanied by microbial infection, especially after surgical operation, which prevents successful cancer therapy. It is necessary to develop a safe and efficient siRNA delivery vector with high anti-bacterial capability. Here, three multifunctional polymeric hybrid micelles (PHM1, PHM2 and PHM3) with high antimicrobial activity were prepared by mixing polymers PEG-b-P3/4HB-b-PEI-b-FA (EHP-FA) and PEG-b-P3/4HB-b-EPL (EHE) copolymer at different mixing ratios and evaluated for targeted siRNA delivery and anti-infection applications. The PHM micelles, taking advantage of the binding ability of EHE and the protection ability of EHP-FA, could effectively combine, protect siRNA, release complexed siRNA and target cancer cells. Additionally, PHM micelles displayed good hemocompatibility, lower cytotoxicity and higher gene silencing efficiency than commercial PEI (25 kDa) in A549, HeLa, HepG2 and C2C12 cells. Through optimizing the ratio of EHP-FA and EHE, PHM/sip65 showed a high p65 gene silencing efficiency above 90% in various cancer cells, which were significantly higher than EHP-FA/sip65 alone and EHE/sip65 complexes. Furthermore, PHM2 micelles showed excellent antimicrobial activity towards positive bacteria (S. aureus) in vitro and in vivo. Our study may provide a facile strategy to develop multifunctional polymer gene vectors for highly promising siRNA delivery and anti-infection.

Directing the nanoparticle formation by the combination with small molecular assembly and polymeric assembly for topical suppression of ocular inflammation

In this paper, we presented a simple yet versatile strategy to generate a high drug payload nanoparticles by the combination with small molecular assembly and polymeric assembly for topical suppression of ocular inflammation. Upon physical mixing of the succinated triamcinolone acetonide (TA-SA) supramolecular hydrogel with the poly (ethylene glycol)-poly (ɛ-caprolactone)-poly (ethylene glycol) (PECE) aqueous solution at 37 °C, TA-SA/PECE nanoparticles formed spontaneously and characterized thoroughly by transmission electron microscopy (TEM), X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The formed TA-SA/PECE nanoparticles displayed a comparable in vitro anti-inflammatory efficacy to that of native triamcinolone acetonide (TA), through a significant downregulation of various proinflammatory cytokines levels (e.g., NO, TNF-α) in a lipopolysaccharide (LPS) actived RAW264.7 macrophage. Meanwhile, the enhanced transcorneal drug permeability of TA-SA/PECE nanoparticles over that of TA suspension was clearly observed in an isolated rabbit cornea. Intraocular biocompatibility test demonstrated that TA-SA/PECE nanoparticles presented good biocompatibility after topical instillation during entire study period. More importantly, the TA-SA/PECE nanoparticles displayed superior therapeutic efficacy over that of the TA suspension in the endotoxin-induced uveitis (EIU) rabbit model via decreasing neutrophil infiltration in anterior chamber. Overall, the proposed TA-SA/PECE nanoparticles might be a promising candidate for uveitis therapy.