Cationic polymers and their therapeutic potential

Charge Density and Hydrophobicity-Dominated Regimes in the Phase Behavior of Complex Coacervates

The role of hydrophobicity, and particularly of nonionic hydrophobic comonomers, in the phase behavior of polyelectrolyte complex coacervates is not well-understood. Here, we address this problem by synthesizing a library of polymers with a wide range of charge densities and nonionic hydrophobic side chain lengths, and characterizing their phase behavior by optical turbidity. The polymers were prepared by postpolymerization modification of poly(N-acryloxy succinimide), targeting charge densities between 40 and 100% and nonionic aliphatic side chains with lengths from 0 to 12 carbons long. Turbidity measurements on pairs of polycations and polyanions with matched charge densities and nonionic side chain lengths revealed a complex salt response with distinct charge density-dominated and hydrophobicity-dominated regimes. The polymer solubilities were not directly correlated with the phase behavior of the coacervates, indicating the difficulty of understanding the coacervate phase behavior in terms of the polymer-water interaction parameter. This result suggests that there is significant room for further work to understand the mechanisms by which specific molecular-scale interactions moderate the phase behavior of complex coacervates.

Regulation of oligonucleotide adsorption by a thermo and pH dual-responsive copolymer layer

Oligonucleotides hold great promise as therapeutic agents to specifically and selectively inhibit gene expression. In order to achieve better targeting efficiency and treatment efficacy, nanocarriers that are dual-responsive to both temperature and pH are more attractive and suitable due to the fact that certain malignancies can cause a slight increase of local temperature and a minor decrease in extracellular pH around the tumor site at the same time. Here, we systematically study oligonucleotide adsorption on the poly(ethyleneimine)-b-poly(N-isopropylacrylamide) (PEI-b-PNIPAm) copolymer layer grafted on a planar surface and nanoparticles with various radii, where the single effect of temperature or pH alone on oligonucleotide adsorption has been extensively investigated, but the combined effect of temperature and pH is less discussed. The theoretical results show that the surface density of the adsorbed oligonucleotides exhibits thermo and pH dual-responsive behavior, in which temperature and pH exhibit a combined effect on the loading capacity of the oligonucleotides. The underlying molecular mechanism of the dual-responsive behavior is revealed. Besides, the effect of important but coupled parameters in nanocarrier design such as polymer surface coverage and length, salt concentration as well as surface curvature (inverse nanoparticle radius) that may influence the dual-responsive behavior of oligonucleotide adsorption is further discussed, which is of great significance to direct the optimal design of PNIPAm/PEI-based nanocarriers to improve the transfection efficiency by achieving the maximal loading capacity of oligonucleotides at different temperatures and pH values.

Long Non-Coding RNAs in the Tumor Immune Microenvironment: Biological Properties and Therapeutic Potential

Cancer immunotherapy (CIT) is considered a revolutionary advance in the fight against cancer. The complexity of the immune microenvironment determines the success or failure of CIT. Long non-coding RNA (lncRNA) is an extremely versatile molecule that can interact with RNA, DNA, or proteins to promote or inhibit the expression of protein-coding genes. LncRNAs are expressed in many different types of immune cells and regulate both innate and adaptive immunity. Recent studies have shown that the discovery of lncRNAs provides a novel perspective for studying the regulation of the tumor immune microenvironment (TIME). Tumor cells and the associated microenvironment can change to escape recognition and elimination by the immune system. LncRNA induces the formation of an immunosuppressive microenvironment through related pathways, thereby controlling the escape of tumors from immune surveillance and promoting the development of metastasis and drug resistance. Using lncRNA as a therapeutic target provides a strategy for studying and improving the efficacy of immunotherapy.

Hydrogel-Induced Cell Membrane Disruptions Enable Direct Cytosolic Delivery of Membrane-Impermeable Cargo

Intracellular delivery of membrane-impermeable cargo offers unique opportunities for biological research and the development of cell-based therapies. Despite the breadth of available intracellular delivery tools, existing protocols are often suboptimal and alternative approaches that merge delivery efficiency with both biocompatibility, as well as applicability, remain highly sought after. Here, a comprehensive platform is presented that exploits the unique property of cationic hydrogel nanoparticles to transiently disrupt the plasma membrane of cells, allowing direct cytosolic delivery of uncomplexed membrane-impermeable cargo. Using this platform, which is termed Hydrogel-enabled nanoPoration or HyPore, the delivery of fluorescein isothiocyanate (FITC)-dextran macromolecules in various cancer cell lines and primary bovine corneal epithelial cells is convincingly demonstrated. Of note, HyPore demonstrates efficient FITC-dextran delivery in primary human T cells, outperforming state-of-the-art electroporation-mediated delivery. Moreover, the HyPore platform enables cytosolic delivery of functional proteins, including a histone-binding nanobody as well as the enzymes granzyme A and Cre-recombinase. Finally, HyPore-mediated delivery of the MRI contrast agent gadobutrol in primary human T cells significantly improves their T₁ -weighted MRI signal intensities compared to electroporation. Taken together, HyPore is proposed as a straightforward, highly versatile, and cost-effective technique for high-throughput, ex vivo manipulation of primary cells and cell lines.

QSPR modelling for investigation of different properties of aminoglycoside-derived polymers using 2D descriptors

The quantitative structure-property relationship (QSPR) method is commonly used to predict different physicochemical characteristics of interest of chemical compounds with an objective to accelerate the process of design and development of novel chemical compounds in the biotechnology and healthcare industries. In the present report, we have employed a QSPR approach to predict the different properties of the aminoglycoside-derived polymers (i.e. polymer DNA binding and aminoglycoside-derived polymers mediated transgene expression). The final QSPR models were obtained using the partial least squares (PLS) regression approach using only specific categories of two-dimensional descriptors and subsequently evaluated considering different internationally accepted validation metrics. The proposed models are robust and non-random, demonstrating excellent predictive ability using test set compounds. We have also developed different kinds of consensus models using several validated individual models to improve the prediction quality for external set compounds. The present findings provide new insight for exploring the design of an aminoglycoside-derived polymer library based on different identified physicochemical properties as well as predict their property before their synthesis.

Structures and strategies for enhanced sensitivity of polydiacetylene(PDA) based biosensor platforms

Polydiacetylene (PDA) is a versatile polymer that has been studied in numerous fields because of its unique optical properties derived from alternating multiple bonds in the polymer backbone. The conjugated structure in the polymer backbone enables PDA to possess the ability of blue-red colorimetric transition when π-π interactions in the PDA backbone chain are disturbed by the external environment. The chromatic property of PDA disturbed by external stimuli can also emit fluorescence in the red region. Owing to the unique characteristics of PDA, it has been widely studied in facile and label-free sensing applications based on colorimetric or fluorescence signals for several decades. Among the various PDA structures, membrane structures assembled by amphiphilic molecules are widely used as a versatile platform because facile modification of the synthetic membrane provides extensive applications, such as receptor-ligand interactions, resulting in potent biosensors. To use PDA as a sensory material, several methods have been studied to endow the specificity to PDA molecules and to amplify the signal from PDA supramolecules. This is because selective and sensitive detection of target materials is required at an appropriate level corresponding to each material for applicable sensor applications. This review focuses on factors that affect the sensitivity of PDA composites and several strategies to enhance the sensitivity of the PDA sensor to various structures. Owing to these strategies, the PDA sensor system has achieved a higher level of sensitivity and selectivity, enabling it to detect multiple target materials for a full field of application.

Antimicrobial Polymer-Based Assemblies: A Review

An antimicrobial supramolecular assembly (ASA) is conspicuous in biomedical applications. Among the alternatives to overcome microbial resistance to antibiotics and drugs, ASAs, including antimicrobial peptides (AMPs) and polymers (APs), provide formulations with optimal antimicrobial activity and acceptable toxicity. AMPs and APs have been delivered by a variety of carriers such as nanoparticles, coatings, multilayers, hydrogels, liposomes, nanodisks, lyotropic lipid phases, nanostructured lipid carriers, etc. They have similar mechanisms of action involving adsorption to the cell wall, penetration across the cell membrane, and microbe lysis. APs, however, offer the advantage of cheap synthetic procedures, chemical stability, and improved adsorption (due to multipoint attachment to microbes), as compared to the expensive synthetic routes, poor yield, and subpar in vivo stability seen in AMPs. We review recent advances in polymer-based antimicrobial assemblies involving AMPs and APs.

Development of Catechin, Poly-l-lysine, and Double-Stranded RNA Nanoparticles

Developing strategies to optimize double-stranded RNA (dsRNA) delivery remains a significant challenge in improving RNA interference (RNAi) in insects. Nanoformulations may provide an avenue for the safe and effective delivery of dsRNA. We investigated nanoparticle-mediated gene silencing using biodegradable polymers, poly-l-lysine (PLL), and polyphenol (-)-epigallocatechin gallate (EGCG) for dsRNA delivery into Spodoptera frugiperda (Sf9) cells. Negatively charged cores were formed by EGCG and dsRNA complexes, and PLL was used to encapsulate the cores. The nanoparticles were characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM), and energy-dispersive spectrometry (EDS) analysis. The stability of the nanoparticles was assessed by incubating them in nuclease-containing Sf9 cell conditioned media. The effectiveness of the nanoparticles was investigated in Sf9 cells stably expressing the luciferase gene. The results revealed that the nanoparticles formed were small and spherical. The PLL/EGCG/dsRNA nanoparticles exhibited better stability compared to that of PLL/dsRNA or naked dsRNA. Nanoparticles prepared with dsRNA targeting the luciferase gene induced an efficient knockdown (66.7%) of the target gene. In Sf9 cells, nanoparticles prepared with Cy3- or CyPHer-5E-labeled dsRNA showed higher cellular uptake and endosomal escape, respectively, than the naked dsRNA. The improvement in uptake and cytosolic delivery may have helped to increase the knockdown efficiency. In Sf9 cells, the nanoparticles prepared with dsRNA targeting the inhibitor of apoptosis gene induced apoptosis by knocking down its expression. In conclusion, we demonstrate that PLL/EGCG/dsRNA nanoparticles are stable, highly efficient, and effective in dsRNA delivery and knockdown of the target gene.

Red Light-Triggered Intracellular Carbon Monoxide Release Enables Selective Eradication of MRSA Infection

Carbon monoxide (CO) is an important gaseous signaling molecule. The use of CO-releasing molecules such as metal carbonyls enables the elucidation of the pleiotropic functions of CO. Although metal carbonyls show a broad-spectrum antimicrobial activity, it remains unclear whether the bactericidal property originates from the transition metals or the released CO. Here, we develop nonmetallic CO-releasing micelles via a photooxygenation mechanism of 3-hydroxyflavone derivatives, enabling CO release under red light irradiation (e.g., 650 nm). Unlike metal carbonyls that non-specifically internalize into both Gram-positive and Gram-negative bacteria, the nonmetallic micelles are selectively taken up by S. aureus instead of E. coli cells, exerting a selective bactericidal effect. Further, we demonstrate that the CO-releasing micelles can cure methicillin-resistant S. aureus (MRSA)-infected wounds, simultaneously eradicating MRSA pathogens and accelerating wound healing.

Polymeric Delivery of Therapeutic Nucleic Acids

The advent of genome editing has transformed the therapeutic landscape for several debilitating diseases, and the clinical outlook for gene therapeutics has never been more promising. The therapeutic potential of nucleic acids has been limited by a reliance on engineered viral vectors for delivery. Chemically defined polymers can remediate technological, regulatory, and clinical challenges associated with viral modes of gene delivery. Because of their scalability, versatility, and exquisite tunability, polymers are ideal biomaterial platforms for delivering nucleic acid payloads efficiently while minimizing immune response and cellular toxicity. While polymeric gene delivery has progressed significantly in the past four decades, clinical translation of polymeric vehicles faces several formidable challenges. The aim of our Account is to illustrate diverse concepts in designing polymeric vectors towards meeting therapeutic goals of in vivo and ex vivo gene therapy. Here, we highlight several classes of polymers employed in gene delivery and summarize the recent work on understanding the contributions of chemical and architectural design parameters. We touch upon characterization methods used to visualize and understand events transpiring at the interfaces between polymer, nucleic acids, and the physiological environment. We conclude that interdisciplinary approaches and methodologies motivated by fundamental questions are key to designing high-performing polymeric vehicles for gene therapy.

Multifunctional Immunoadjuvants for Use in Minimalist Nucleic Acid Vaccines

Subunit vaccines based on antigen-encoding nucleic acids have shown great promise for antigen-specific immunization against cancer and infectious diseases. Vaccines require immunostimulatory adjuvants to activate the innate immune system and trigger specific adaptive immune responses. However, the incorporation of immunoadjuvants into nonviral nucleic acid delivery systems often results in fairly complex structures that are difficult to mass-produce and characterize. In recent years, minimalist approaches have emerged to reduce the number of components used in vaccines. In these approaches, delivery materials, such as lipids and polymers, and/or pDNA/mRNA are designed to simultaneously possess several functionalities of immunostimulatory adjuvants. Such multifunctional immunoadjuvants encode antigens, encapsulate nucleic acids, and control their pharmacokinetic or cellular fate. Herein, we review a diverse class of multifunctional immunoadjuvants in nucleic acid subunit vaccines and provide a detailed description of their mechanisms of adjuvanticity and induction of specific immune responses.

g_elpot: A Tool for Quantifying Biomolecular Electrostatics from Molecular Dynamics Trajectories

Electrostatic forces drive a wide variety of biomolecular processes by defining the energetics of the interaction between biomolecules and charged substances. Molecular dynamics (MD) simulations provide trajectories that contain ensembles of structural configurations sampled by biomolecules and their environment. Although this information can be used for high-resolution characterization of biomolecular electrostatics, it has not yet been possible to calculate electrostatic potentials from MD trajectories in a way allowing for quantitative connection to energetics. Here, we present g_elpot, a GROMACS-based tool that utilizes the smooth particle mesh Ewald method to quantify the electrostatics of biomolecules by calculating potential within water molecules that are explicitly present in biomolecular MD simulations. g_elpot can extract the global distribution of the electrostatic potential from MD trajectories and measure its time course in functionally important regions of a biomolecule. To demonstrate that g_elpot can be used to gain biophysical insights into various biomolecular processes, we applied the tool to MD trajectories of the P2X3 receptor, TMEM16 lipid scramblases, the secondary-active transporter Glt_Ph, and DNA complexed with cationic polymers. Our results indicate that g_elpot is well suited for quantifying electrostatics in biomolecular systems to provide a deeper understanding of its role in biomolecular processes.

Disaccharide-polyethylenimine organic nanoparticles as non-toxic in vitro gene transporters and their anticancer potential

Polyethylenimines (PEIs) have been shown as efficient gene delivery vectors due to their unique properties, however, toxicity as well as non-specific interactions with the tissues/cells because of high charge density have hampered their use in clinical applications. To counter these concerns, here, we have prepared disachharide-PEI organic nanoparticles by mixing PEIs with non-reducing disaccharides, i.e. trehalose (TPONs) and sucrose (SPONs), under mild conditions. The fabricated nanoparticles were complexed with pDNA and size of these complexes was found in the range of ~130-162 nm with zeta potential ~ +8-25 mV. Further evaluation of these nanoparticles revealed that substitution of disaccharides on PEIs successfully augmented cell viability. Transfection efficiency exhibited by these complexes was significantly higher than the unmodified polymer and the standard, Lipofectamine, complexes. Fabrication of organic nanoparticles did not alter the buffering capacity considerably which was found to be instrumental during endosomal escape of the complexes. Among both the series of nanoparticles, trehalose-PEI organic nanoparticles (TPONs) exhibited greater pDNA transportation potential than sucrose-PEI organic nanoparticles (SPONs) which was also established by flow cytometric data, wherein percent cells expressing GFP was higher in case of TP/pDNA complexes as compared to SP/pDNA complexes. Interestingly, TPONs also showed promising anticancer activity on cancer cell lines i.e. Mg63, MCF-7 and HepG2. Overall, the results advocate promising potential of disaccharide-PEI organic nanoparticles as efficient gene delivery agents which can be used effectively in future gene therapy applications along with anti-cancer competence of TPONs.

A Hybrid Biological-Biomaterial Vector for Antigen Delivery

A hybrid biological-biomaterial vector composed of a biocompatible polymeric biomaterial coating and an Escherichia coli core was designed and developed for antigen delivery. It provides a unique and efficient mechanism to transport antigens (protein or genetic) via different mechanisms of vector design that include antigen cellular localization (cytoplasm, periplasm, cellular surface) and nonnative functionalities that assist in antigen delivery. Based on a variety of E. coli strain development and polymer chemistry tools, the hybrid vector can be constructed into a number of formats for the purpose of optimized uptake and processing by antigen presenting cells, serving as the basis for a potent subsequent immune response. This chapter serves to outline a protocol for assembling a hybrid biological-biomaterial vector for use as a vaccine delivery system.

Cationic polymer synergizing with chemotherapeutics and re-purposing antibiotics against cancer cells

Chemotherapy is one of the most effective treatments for cancer. However, toxicity and the development of drug resistance have become the major hurdles to the commonly used chemotherapeutics such as doxorubicin and paclitaxel. Antibiotics have also been used as anti-cancer drugs due to their anti-proliferative and cytotoxic effects. However, these anti-tumor antibiotics like ciprofloxacin face the similar resistance and toxicity issues. In this study, we used a quaternary ammonium-functionalized cationic polycarbonate to synergize with the existing chemotherapeutics and re-purpose antibiotics to address the resistance and toxicity issues. When used in combination with the drugs, the cationic polymer induced 2-3 fold more damage in the cancer cell membrane within 2 hours, thus enhancing the uptake of chemotherapeutics up to 2.5 fold more into the breast, liver and even chemotherapeutics-resistant cancer cells. On the other hand, the chemotherapeutics increased the cellular uptake of polymer. The combined effects resulted in 3-10 fold reduction in IC₅₀ of chemotherapy drugs and yielded therapeutic synergy at a clinically-relevant concentration range of drugs when treating multiple types of cancer cells, while the use of guanidinium-functionalized polymer capable of membrane translocation did not lead to a synergistic effect. Thus, the quaternary ammonium-functionalized cationic polymer can increase the therapeutic efficacies of existing drugs, mitigating toxicities by lowering required dosage and circumventing drug resistance via its membrane disruption mechanism. The findings of this study provide insights into designing future anticancer therapy.

Polymeric antibacterial materials: design, platforms and applications

Over the past decades, the morbidity and mortality caused by pathogen invasion remain stubbornly high even though medical care has increasingly improved worldwide. Besides, impacted by the ever-growing multidrug-resistant bacterial strains, the crisis owing to the abuse and misuse of antibiotics has been further exacerbated. Among the wide range of antibacterial strategies, polymeric antibacterial materials with diversified synthetic strategies exhibit unique advantages (e.g., their flexible structural design, processability and recyclability, tuneable platform construction, and safety) for extensive antibacterial fields as compared to low molecular weight organic or inorganic antibacterial materials. In this review, polymeric antibacterial materials are summarized in terms of four structure styles and the most representative material platforms to achieve specific antibacterial applications. The superiority and defects exhibited by various polymeric antibacterial materials are elucidated, and the design of various platforms to elevate their efficacy is also described. Moreover, the application scope of polymeric antibacterial materials is summarized with regard to tissue engineering, personal protection, and environmental security. In the last section, the subsequent challenges and direction of polymeric antibacterial materials are discussed. It is highly expected that this critical review will present an insight into the prospective development of antibacterial functional materials.

In Vitro Antiprotozoal Effects of Nano-chitosan on Plasmodium falciparum, Giardia lamblia and Trichomonas vaginalis

BACKGROUND

Treatment of parasitic infections with conventional drugs is associated with high toxicity, and undesirable side effects require cogent substitutions. Nanotechnology has provided novel approaches to synthesize nano-drugs to improve efficient antipathetic treatment.

PURPOSE

Nano-chitosan as a nontoxic antimicrobial agent was examined against three most prevalent protozoa in humans, Plasmodium falciparum, Giardia lamblia and Trichomonas vaginalis.

METHODS

Chitosan extracted from Penicillium fungi was converted to nanoparticles to maximize its therapeutic properties. Safety of nano-chitosan was examined by determining its hemolytic property and toxicity on PC12 cells. The studied parasites were identified with RFLP-PCR and cultivation in relevant media. Characteristics of nano-chitosan as an useful and valuable curative compound was evaluated by FTIR, DLS and SEM. Dose dependent anti-parasitic effect of nano-chitosan was evaluated.

RESULTS

The highest anti-parasitic activity of the nano-chitosan was observed at 50 μg/mL by which growth rates of cultivated P. falciparum, T. vaginalis and G. lamblia were inhibited by 59.5%, 99.4%, and 31.3%, respectively. The study demonstrated that nano-chitosan with the least toxicity, low side effects, and substantial efficacy deserved to be considered as an anti-parasitic nano-compound.

CONCLUSION

Nano-chitosan significantly inhibited protozoan growth in vitro promising to explore its use to combat parasitic infections. Further investigations covering extended sample size, in vivo experiments and optimizing the concentration used may lead to efficient treatment of protozoan diseases.

Bioresorbable Polymers: Advanced Materials and 4D Printing for Tissue Engineering

Three-dimensional (3D) printing is a valuable tool in the production of complexes structures with specific shapes for tissue engineering. Differently from native tissues, the printed structures are static and do not transform their shape in response to different environment changes. Stimuli-responsive biocompatible materials have emerged in the biomedical field due to the ability of responding to other stimuli (physical, chemical, and/or biological), resulting in microstructures modifications. Four-dimensional (4D) printing arises as a new technology that implements dynamic improvements in printed structures using smart materials (stimuli-responsive materials) and/or cells. These dynamic scaffolds enable engineered tissues to undergo morphological changes in a pre-planned way. Stimuli-responsive polymeric hydrogels are the most promising material for 4D bio-fabrication because they produce a biocompatible and bioresorbable 3D shape environment similar to the extracellular matrix and allow deposition of cells on the scaffold surface as well as in the inside. Subsequently, this review presents different bioresorbable advanced polymers and discusses its use in 4D printing for tissue engineering applications.

Nanotechnology-Based Antimicrobial and Antiviral Surface Coating Strategies

Biocontamination of medical devices and implants is a growing issue that causes medical complications and increased expenses. In the fight against biocontamination, developing synthetic surfaces, which reduce the adhesion of microbes and provide biocidal activity or combinatory effects, has emerged as a major global strategy. Advances in nanotechnology and biological sciences have made it possible to design smart surfaces for decreasing infections. Nevertheless, the clinical performance of these surfaces is highly depending on the choice of material. This review focuses on the antimicrobial surfaces with functional material coatings, such as cationic polymers, metal coatings and antifouling micro-/nanostructures. One of the highlights of the review is providing insights into the virus-inactivating surface development, which might particularly be useful for controlling the currently confronted pandemic coronavirus disease 2019 (COVID-19). The nanotechnology-based strategies presented here might be beneficial to produce materials that reduce or prevent the transmission of airborne viral droplets, once applied to biomedical devices and protective equipment of medical workers. Overall, this review compiles existing studies in this broad field by focusing on the recent related developments, draws attention to the possible activity mechanisms, discusses the key challenges and provides future recommendations for developing new, efficient antimicrobial and antiviral surface coatings.

Effect of polyelectrolyte complex formation on the antibacterial activity of copolymer of alkylated 4-vinylpyridine

Polymers bearing quaternized 4-vinylpyridine (QVP) groups are known for their antibacterial activities and these polymers can form polyelectrolyte complexes (PEC) with polyanions through electrostatic interactions. PEC formation can be used to adjust the antibacterial activity of polymers of QVP, deliver active molecules, or design antibacterial supramolecular structures. However, the antibacterial activity of PECs of QVP polymers has not been investigated. In this study, a copolymer of QVP was mixed with polyacrylic acid in various molar ratios of components to form PECs. Hydrodynamic diameters and zeta potentials of formed PECs were determined by dynamic and electrophoretic light scattering spectroscopy techniques. The zeta potentials of PECs changed between –24 and +16 mV with variation in the ratio of components. Antibacterial assays against E. coli revealed a relation of PEC formation with antibacterial activity since MIC values changed between 125–1000 μg/mL according to the ratio of components.

High-Throughput Automation of Endosomolytic Polymers for mRNA Delivery

In recent years, there has been an increasing interest in designing delivery systems to enhance the efficacy of RNA-based therapeutics. Here, we have synthesized copolymers comprised of dimethylaminoethyl methacrylate (DMAEMA) or diethylaminoethyl methacrylate (DEAEMA) copolymerized with alkyl methacrylate monomers ranging from 2 to 12 carbons, and developed a high throughput workflow for rapid investigation of their applicability for mRNA delivery. The structure activity relationship revealed that the mRNA encapsulation efficiency is improved by increasing the cationic density and use of shorter alkyl side chains (2-6 carbons). Minimal cytotoxicity was observed when using DEAEMA-co-BMA (EB) polyplexes up to 18 h after dosing, independent of a poly(ethylene glycol) (PEG) first block. The lowest molecular weight polymer (EB10,250) performed best, exhibiting greater transfection than polyethyenimine (PEI) based upon the number of cells transfected and mean intensity. Conventional investigations into the performance of polymeric materials for mRNA delivery is quite tedious, consequently limiting the number of materials and formulation conditions that can be studied. The high throughput approach presented here can accelerate the screening of polymeric systems and paves the way for expanding this generalizable approach to assess various materials for mRNA delivery.

The progress on sulfhydryl modified polymers with regard to synthesis, characterization and mucoadhesion

The concepts of mucoadhesion and mucoadhesive polymers were introduced in the 20th century, leading to several advantages. These included enhanced drug absorption and extended residence at specific site of action. Polymeric excipients underwent chemical modification with sulfhydryl groups on the polymeric backbone so as to improve mucoadhesive features as well as potential. This modification resulted in compounds mimicking the nature of secreted mucus glycoproteins. Thus, these thiol group-bearing excipients presented the ability to attach covalently to the mucosa by the disulfide bonding. Nevertheless, the first generation of these thiol-modified polymers, named thiomers, presented disadvantages such as low stability in aqueous media and/or the high susceptibility towards oxidation along with the drawback of low sufficient reactive functional moieties on the polymeric backbone at lower pH. Therefore, in the 21st century, a second generation of preactivated or S-protected polymers with protected thiol moieties were developed, as well as a third generation of thiomers, solving some of the previously described problems. This review article aimed to highlight the progess on a potent sulfhydryl modification during the last decades and the posterior characterization and in vitro/ex vivo/in vivo mucoadhesiveness.

Synthesis of fully degradable cationic polymers with various topological structures via postpolymerization modification by using thio-bromo “click” reaction

Poly(ε-caprolactone) (PCL) based and fully degradable cationic polymers with various topological structures and tunable charge densities were prepared via postpolymerization modification using thio-bromo “click” chemistry.

Oxidation and ATP dual-responsive block copolymer containing tertiary sulfoniums: self-assembly, protein complexation and triggered release

Alkylation of thioether-containing block copolymer simultaneously incorporated sulfoniums and phenylboronic acid moieties. The co-assembly of this cationic polymer and protein generated micelles with an H₂O₂-and ATP-responsive release profile.

Multiresponsive Transitions of PDMAEMA Brushes for Tunable Surface Patterning

Poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA) is an attractive polymer for switchable surface coatings based on its multiresponsiveness toward environmental triggers (temperature, pH-value, ionic strength). In this in situ study, we present the complex and tunable thermoresponsiveness of PDMAEMA Guiselin brushes (9 nm, dry thickness), which were prepared via an efficient grafting-to approach. Combining in situ atomic force microscopy (AFM) visualizing the surface topography (x-y plane) and spectroscopic ellipsometry monitoring the swelling behavior of the polymer film (layer thickness, z-direction) offers for the first time a three-dimensional insight into thermoresponsive transitions on the nanoscale. While PDMAEMA films exhibit LCST behavior in the presence of monovalent counterions, it can easily be switched toward an UCST thermoresponsiveness via the addition of small quantities of multivalent ions. In both cases, the transition temperature as well as the sharpness and reversibility of the transition can be tuned via a second external trigger, the ionic strength. Whereas homogeneous surfaces were observed both below and above the LCST in monovalent salt solutions, the UCST transition was characterized by the in situ formation of a nanostructured surface of pinned PDMAEMA micelles with entrapped multivalent counterions. Moreover, it was demonstrated for the first time that the characteristic dimensions of the nanopattern (the diameter and height of the pinned micelles) could be tuned in situ by the pH- and induced UCST thermoresponsiveness of PDMAEMA. This approach therefore provides a novel bottom-up strategy to create and control polymeric nanostructures in an aqueous environment.

Optimizing the Polymer Chemistry and Synthesis Method of PolySTAT, an Injectable Hemostat

There is a lack of prehospital hemostatic agents, especially for noncompressible hemorrhage. We previously reported PolySTAT, a unimeric, injectable hemostatic agent, that physically cross-links fibrin to strengthen clots. In this work, we sought to improve the water-solubility and synthesis yield of PolySTAT to increase the likelihood of clinical translation, reduce cost, and facilitate future mass production. First, we focused on side-chain engineering of the carrier polymer backbone to improve water-solubility. We found that substitution of the 2-hydroxyethyl methacrylate (HEMA) monomer with glycerol monomethacrylate (GmMA) significantly improved the water-solubility of PolySTAT without compromising efficacy. Both materials increased clot firmness and decreased lysis as measured by rotational thromboelastometry (ROTEM). Additionally, we confirmed the in vivo activity of GmMA-based PolySTAT by improving rat survival in a femoral artery bleed model. Second, to reduce waste, we evaluated PolySTAT synthesis via direct polymerization of peptide monomers. Methacrylamide and methacrylate peptide-monomers were synthesized and polymerized via reversible addition-fragmentation chain transfer (RAFT) polymerization. This approach markedly improved the yield of PolySTAT synthesis while maintaining its biological activity in ROTEM. This work demonstrates the flexibility of PolySTAT to a variety of comonomers and synthetic routes and establishes direct RAFT polymerization of peptide monomers as a potential route of mass production.

The targeted inhibition of prostate cancer by iron-based nanoparticles based on bioinformatics

Prostate cancer is an epithelial malignant tumor of the prostate, and it is one of the malignant tumors with a high incidence of urogenital system in men. The local treatment of prostate cancer is mainly radical resection and radical radiotherapy, but they are not applicable to advanced prostate cancer. Systemic therapy mainly includes targeted therapy and immunotherapy which could cause many complications, and will affect the prognosis and quality of life of patients. It is urgent to find new treatments for prostate cancer. Bioinformatics offers hope for us to find reliable therapeutic targets. Bioinformatics can use the tumor informations in database and analyze them to screen out the best differentially expressed genes. Using the selected differentially expressed genes as targets, a gene interference plasmid was designed, and the constructed plasmid was used for targeted gene therapy. There are some problems about gene therapy that need to be solved, such as how to transfer genes to target cells is also an important challenge. Due to their large molecular weight and hydrophilic nature, they cannot enter cells through passive diffusion mechanisms. Here we synthesized a DNA carrier used surface modified iron based nanoparticles, and used it to load plasmid including ShRNA which can inhibit the expression of oncogene SLC4A4 selected by bioinformatics’ method. After that we use this iron based nanoparticles/plasmid DNA nanocomposite to treat prostate cancer cells in vitro and in vivo. The target gene SLC4A4 we had selected using bioinformatics had a strong effect on the proliferation of prostate cells; Our nanocomposite could inhibit the expression of SLC4A4 effectively, it had strong inhibitory effects on prostate cancer cells both in vivo and in vitro, and can be used as a potential method for prostate cancer treatment.

Virus Mimetic Shell-Sheddable Chitosan Micelles for siVEGF Delivery and FRET-Traceable Acid-Triggered Release

Targeting vascular endothelial growth factor (VEGF) using small interfering RNA (siVEGF) has shown great potential in inhibiting the growth, proliferation, and migration of tumors by reducing the proliferation of blood vessels. On the basis of bionic principles, a novel pH-responsive and virus mimetic shell-sheddable chitosan (CS) micelles (CMs) as siRNA delivery system was introduced in this study. The cyclo(Arg-Gly-Asp-d-Phe-Lys) (cRGD) modified poly(enthylene glycol) (PEG) was conjugated to the HA2 modified chitosan via a hydrazone linkage (cRGD-PEG-Hz-CS-HA2). The cRGD-PEG-Hz-CS-HA2 conjugate could form micelles by interacting with the complex of octanal, Boc-l-lysine, and 9-d-arginine (9R) (octyl-Lys-9R) as a hydrophodic core forming agent, termed as cRGD-PEG-Hz-CS-HA2/octyl-Lys-9R (abbreviated as cRGD/HA2/Hz-CMs).The CMs modified with cRGD can accurately target glioma cells (U87MG cells) with high expression of αvβ3. The payloads of siVEGF were packed into the core of cRGD/HA2/Hz-CMs via electrostatic interaction and hydrophobic interaction. The intracellular cargo release was achieved by the pH-responsive lysis of the hydrazone bond in acidic environment of endosome. Moreover, the exposed HA2, as a pH-sensitive membrane-disruptive peptide, assists the escape of the carriers from endosome into cytosol. In addition, cRGD/HA2/Hz-CMs can effectively deliver siVEGF and silence VEGF gene expression in U87MG cells, leading to the significant tumor growth inhibition. This study demonstrates that cRGD/HA2/Hz-CMs can deliver and release siVEGF in a controlled manner, which was traced by the fluorescence resonance energy transfer (FRET) system in order to achieve RNAi-based anti-angiogenic treatment of cancer in vivo.

Nanomaterials for Treating Bacterial Biofilms on Implantable Medical Devices

Bacterial biofilms are involved in most device-associated infections and remain a challenge for modern medicine. One major approach to addressing this problem is to prevent the formation of biofilms using novel antimicrobial materials, device surface modification or local drug delivery; however, successful preventive measures are still extremely limited. The other approach is concerned with treating biofilms that have already formed on the devices; this approach is the focus of our manuscript. Treating biofilms associated with medical devices has unique challenges due to the biofilm's extracellular polymer substance (EPS) and the biofilm bacteria's resistance to most conventional antimicrobial agents. The treatment is further complicated by the fact that the treatment must be suitable for applying on devices surrounded by host tissue in many cases. Nanomaterials have been extensively investigated for preventing biofilm formation on medical devices, yet their applications in treating bacterial biofilm remains to be further investigated due to the fact that treating the biofilm bacteria and destroying the EPS are much more challenging than preventing adhesion of planktonic bacteria or inhibiting their surface colonization. In this highly focused review, we examined only studies that demonstrated successful EPS destruction and biofilm bacteria killing and provided in-depth description of the nanomaterials and the biofilm eradication efficacy, followed by discussion of key issues in this topic and suggestion for future development.

Chitosan Nanoparticle Based Mucosal Vaccines Delivered Against Infectious Diseases of Poultry and Pigs

Infectious disease of poultry and pig are major threat to health and cause severe economic loss to the food industry and a global food safety issue. Poultry and pig act as a mixing vessel of zoonotic transmission of disease to humans. Effective mucosal vaccines used in animals could reduce the impact of diseases in food animals. Chitosan is a biocompatible polymer, and its positive charge makes it a natural mucoadhesive agent. Therefore, since last one-decade chitosan derived nanoparticles (CS NPs) have been in use widely to deliver vaccine antigens in animals through mucosal route. Primary route of entry of most infectious disease pathogen is through oral and nasal routes, and the CS NPs based vaccines delivered through that routes enhance the immunogenicity of encapsulated vaccine antigens by targeting the cargo to mucosal microfold cells, dendritic cells and macrophages. Resulting in induction of robust secretory and systemic antibodies and/or cell mediated immune response which provides protection against infections. To date, CS NPs is being widely used for mucosal vaccine delivery in poultry and pigs to control bacterial and viral infections, and tested in several preclinical trials for vaccine delivery in humans. In this review, we highlighted the progress so far made in using CS NPs as a vehicle for mucosal vaccine delivery against infectious and zoonotic diseases of poultry and pigs. Discussed about the need of CS NPs modifications, CS NPs based vaccines induced immune responses and its role in protection, and challenges in vaccination and future directions.

Selenonium Polyelectrolyte Synthesis through Post-Polymerization Modifications of Poly (Glycidyl Methacrylate) Scaffolds

Atom transfer radical polymerization of glycidyl methacrylate monomer with poly(ethylene glycol)-based macroinitiators leads to the formation of reactive block copolymers. The epoxide side-chains of these polymers can be subjected to a regiospecific base-catalyzed nucleophilic ring-opening reaction with benzeneselenol under ambient conditions. The ß-hydroxy selenide linkages thus formed can be alkylated to access polyselenonium salts. 77Se-NMR indicates the formation of diastereomers upon alkylation. In such a manner, sequential post-polymerization modifications of poly(glycidyl methacrylate) scaffolds via selenium-epoxy and selenoether alkylation reactions furnish practical access to poly(ethylene glycol)-based cationic organoselenium copolymers.

Cellular gene delivery via poly(hexamethylene biguanide)/pDNA self-assembled nanoparticles

Cellular gene delivery via polycations has wide implications for the potential of gene therapy, but it has remained a challenge due to the plethora of pre- and post-uptake barriers that must be overcome to reach desired efficiency. Herein we report poly(hexamethylene biguanide) (PHMB) as a nano-vector for intracellular delivery of plasmid DNA (pDNA) and oligodeoxynucleotides (ODNs). PHMB and pDNA or ODNs self-assembled into complex nanoparticles at different pH values (7.4 and 12). Their size, charge, cellular uptake, and gene-expression efficiency are assessed and compared to PEI analogues. The systematic results show that the nanoparticles are effective in delivering plasmid DNA and ODNs to model cell lines in culture (HepG2, HEK293T, HeLa), with measurable changes in gene expression levels, comparable to and, in some conditions, even higher than PEI. The well-accepted safety profile of PHMB makes it a valuable candidate for consideration as an effective intracellular DNA vector for further study and potential clinical translation.

A Cationic Stearamide-based Solid Lipid Nanoparticle for Delivering Yamanaka Factors: Evaluation of the Transfection Efficiency

Induced pluripotent stem cells (IPSC) are preferred as an alternative source for regenerative medicine, disease modeling, and drug screening due to their unique properties. As seen from the previous studies in the literature, most of the vector systems to transfer reprogramming factors are viral-based and have some well-known limitations. This study aims to develop a non-viral vector system for the transfection of reprogramming factors. Cationic stearamide lipid nanoparticles (CSLN) were prepared via the solvent diffusion method. The obtained CSLNs were used for the delivery of plasmid DNA (pDNA) encoding Oct3/4, Sox2, Klf4, and GFP to fibroblast cell lines. The optimization studies, for zeta potential and particle size of the conjugate, was performed to achieve high cell viability. CSLN63 with 36.5±0.06 mV zeta potential and 173.6±13.91 nm size was used for the transfection of Fibroblast cells. The transfection efficiency was observed by following GFP expression and was found as 70 %±0.11. The expression of the Oct4, Sox2, Klf4 was determined by RT-qPCR; an increase was observed after the 12th cycle in Klf4 (Ct averages: 13,41), Sox2 (Ct averages; 12,4), Oct4 (Ct average; 13,77). The tendency of colonization was observed. The upregulation efficiency of Oct4 and SSEA-1 with CSLN and another non-viral vector designed for the transportation of Yamanaka factors developed in our lab previously were compared with flow cytometer analysis.

Improving the Activity of DNA-Encoded Sensing Elements through Confinement in Silk Microcapsules

Assembling synthetic bioparts into simplified artificial cells holds tremendous promise for advancing studies into the synthesis, biosensing, and delivery of biomolecules. Currently, the most successful techniques for encapsulation of the transcription-translation machinery exploit compartmentalization in liposomal vesicles. However, improvements to these methods may increase permeability to polar molecules, functionalization of the membrane with biologically active elements, and encapsulation efficiency. Microcapsules prepared via templated layer-by-layer (LbL) assembly using natural polymers have the potential to resolve some of the hurdles associated with liposomes. Here, we introduce a design for immobilizing DNA templates encoding translationally activated riboswitches and RNA aptamers into microcapsules prepared from regenerated silk fibroin protein. Adjusting several key parameters such as the presence of a polymer primer, concentration of silk protein, and DNA loadings during LbL assembly resulted in biocompatible, semipermeable, DNA-laden microcapsules. To preserve bioactivity, DNA was immobilized inside of the capsule membrane, which not only promoted stability during long-term storage at ambient conditions but also improved output response from spatially confined DNA-encoded sensing elements (SEs). Multiple copies of mRNA and GFPa1 protein were synthesized upon activation with specific analytes during in vitro transcription/translation reactions, demonstrating that selective permeability of silk microcapsules was essential for the diffusion of components of the cell-free system inside of the capsules. Further functionalization of capsule shells with gold nanoparticles (AuNPs) and antibodies (IgG) demonstrated the applicability of microcompartmentalized colloidal objects carrying SEs for remote sensing and/or targeted delivery. In the future, multifunctional, biocompatible silk-based microcapsules loaded with different RNA sensors can help advance the design of multiplexed biosensors tracking multiple biomarkers in complex media.

Polyphenol-Based Nanoparticles for Intracellular Protein Delivery via Competing Supramolecular Interactions

Intracellular delivery of proteins is a promising strategy for regulating cellular behavior and therefore has attracted interest for biomedical applications. Despite the emergence of various nanoparticle-based intracellular delivery approaches, it remains challenging to engineer a versatile delivery system capable of responding to various physiological triggers without the need for complex chemical synthesis of the delivery system. Herein, we develop a template-mediated supramolecular assembly strategy to synthesize protein-polyphenol nanoparticles (NPs) capable of endosomal escape and subsequent protein release in the cytosol. These NPs are stable in serum and undergo surface charge reversal from negative to positive in acidic environments, leading to spontaneous endosomal escape. In the cytosol, endogenous small peptides and amino acids with relatively high charge densities, such as glutathione, trigger NP disassembly through competitive supramolecular interactions, thereby releasing functional bioactive proteins, as validated using cytochrome C and β-galactosidase. The versatility of the present strategy in terms of nanoparticle size, protein type, and functional protein delivery makes this a promising platform for potential application in the field of protein therapeutics.

Multicomponent Polymerization toward Cationic Polymers for Efficient Gene Delivery

A new class of cationic polymers containing tertiary amine, thioether, and hydroxyl groups are prepared via a catalyst-free, multicomponent polymerization method using dithiol, formaldehyde, and di-sec-amine with a ratio of 1:2:1, to access a library of water-soluble polymers with well-defined structures and suitable molecular weights (M_w ranging from 5000 to 8000 Da) in high yields (up to 90%). Such polycations are demonstrated to be promising nonviral gene delivery vectors with high transfection efficiency (up to 3.5-fold of PEI25k) and low toxicity with multiple functionalities: 1) efficient gene condensation by tertiary amine groups; 2) reactive oxygen species scavenging by thioether groups; and 3) positive charge shielding by hydroxyl groups. Both the thioether and hydroxyl groups are contributed to reduce the cytotoxicity of the polycations by tuning the oxidative stress and preventing the undesired serum binding. The optimized polycations can achieve high transfection efficiency under the serum conditions, indicating the great potential as a nonviral gene delivery vector candidate for clinical application.

Application, Synthesis, and Characterization of Cationic Galactomannan from Ruderal Species as a Wet Strength Additive and Flocculating Agent

There has been a cumulative interest across the globe in substituting the synthetic materials with sustainable, economical, and biobased green alternatives for utilization in diverse industrial applications. Galactomannans are among the most important sustainable, biodegradable macromolecules abundantly produced by plants, which can be exploited for a range of end-use applications. Functionalization of the galactomannans may improve the physicochemical properties for diverse industrial applications. In the present study, the cationic derivative of Cassia tora gum, a 1:5 galactomannan, was synthesized under heterogeneous alkaline conditions using CHPTAC. The effect of each reaction parameter on the degree of substitution (DS) was investigated using Taguchi L16 orthogonal array. The optimized cationic product with DS 0.28 showed promising results as a biopolymeric flocculant for wastewater treatment and as a wet strength additive for improving the physical strength of paper prepared from old corrugated carton for its recycling. The optimized product was characterized by advanced spectroscopic methods.

A Lactose-Derived CRISPR/Cas9 Delivery System for Efficient Genome Editing In Vivo to Treat Orthotopic Hepatocellular Carcinoma

Gene editing is a crucial and effective strategy to treat genetic diseases. Safe and effective delivery vectors are specially required for efficient gene editing in vivo of CRISPR/Cas9 system. Interestingly, lactose, a natural saccharide, can specifically bind to asialoglycoprotein receptors, highly expressed on the surface of hepatocellular carcinoma (HCC) cells. Herein, a lactose-derived branched cationic biopolymer (LBP) with plentiful reducible disulfide linkages and hydroxyl groups is proposed as a potential delivery vector of CRISPR/Cas9 system for efficient genome editing in vivo to treat orthotopic HCC. LBP is synthesized via a facile one-pot ring-opening reaction. LBP possesses excellent compacting ability, degradability, biocompatibility, gene transfection performances, and HCC-targeting ability. LBP-mediated delivery of classical pCas9-survivin, which can target and knockout survivin oncogene, produces efficient gene editing performances, and superb anti-cancer activities in orthotopic HCC mouse models. This study provides an attractive and safe strategy for the rational design of CRISPR/Cas9 delivery system.