A new solvent-free pathway for inducing quaternized lignin-derived high molecular weight polymer

In this work, kraft lignin (KL) was polymerized with vinylbenzyl chloride (VBC) in a molar ratio of 1.8:1 (KL: VBC) using sodium persulfate (Na2S2O8) as an initiator at pH 9-10 and temperature of 80-90 °C for 3 h to produce polymer kraft lignin-g-poly(4-vinylbenzyl chloride) KL-poly(VBC) 1. Then, the grafting reaction was conducted with two different imidazole-based monomers of different side-chain lengths (methyl and n-butyl), namely, 1-methylimidazole (MIM), 1-n-butylimidazole (BIM), which led to the formation of novel polymers, kraft lignin-g-poly(4-vinylbenzyl-1-methylimidazolium chloride) KL-poly(VBC-MIM) 2a and kraft lignin-g-poly(4-vinylbenzyl-1-n-butyl imidazolium chloride) KL-poly(VBC-BIM) 2b. The polymer 2a generated a larger molecular weight polymer with a higher charge density and solubility than polymer 2b since the n-butyl group would cause steric hindrance and weaker monomer to react with intermediate polymer 1 in the second stage. The contact angle analysis confirmed more hydrophilicity of polymer 2a, and elemental analysis confirmed the more successful polymerization of polymer 2a. Applying the generated polymers as flocculants for a kaolin suspension confirmed that polymer 2a had similar performance with commercial cationic polyacrylamide (CPAM) flocculants, even though polymer 2a had a smaller molecular weight. This polymerization offers a promising pathway for generating cationic polymers with excellent performance as a flocculant for suspensions.

Biotinylated Polymer-Ruthenium Conjugates: In Vitro and In Vivo Studies in a Triple-Negative Breast Cancer Model

The need for new therapeutic approaches for triple-negative breast cancer is a clinically relevant problem that needs to be solved. Using a multi-targeting approach to enhance cancer cell uptake, we synthesized a new family of ruthenium(II) organometallic complexes envisaging simultaneous active and passive targeting, using biotin and polylactide (PLA), respectively. All compounds with the general formula, [Ru(η5-CpR)(P)(2,2'-bipy-4,4'-PLA-biotin)][CF3SO3], where R is -H or -CH3 and P is P(C6H5)3, P(C6H4F)3 or P(C6H4OCH3)3, were tested against triple-negative breast cancer cells MDA-MB-231 showing IC50 values between 2.3-14.6 µM, much better than cisplatin, a classical chemotherapeutic drug, in the same experimental conditions. We selected compound 1 (where R is H and P is P(C6H5)3), for further studies as it was the one showing the best biological effect. In a competitive assay with biotin, we showed that cell uptake via SMVT receptors seems to be the main transport route into the cells for this compound, validating the strategy of including biotin in the design of the compound. The effects of the compound on the hallmarks of cancer show that the compound leads to apoptosis, interferes with proliferation by affecting the formation of cell colonies in a dose-dependent manner and disrupts the cell cytoskeleton. Preliminary in vivo assays in N: NIH(S)II-nu/nu mice show that the concentrations of compound 1 used in this experiment (maximum 4 mg/kg) are safe to use in vivo, although some signs of liver toxicity are already found. In addition, the new compound shows a tendency to control tumor growth, although not significantly. In sum, we showed that compound 1 shows promising anti-cancer effects, bringing a new avenue for triple-negative breast cancer therapy.

Preparation, physicochemical characterization, and anti-proliferative properties of Lawsone-loaded solid lipid nanoparticles

Lawsone (LWS) is a naphthoquinone-type dye with potential antitumor activity. LWS is used in cosmetics for coloring hair, skin, and nails. In this study, solid lipid nanoparticles (SLNs) containing LWS were prepared using a hot homogenization technique. Physicochemical properties of LWS-SLNs including encapsulation efficiency (EE), drug loading (DL), size, zeta potential, homogeneity, in vitro release, and kinetics of release were determined. The potential cytotoxic properties of LWS-SLNs were investigated. Comet assay was done to assess the genotoxicity of LWS-SLNs. The scanning electron microscopy (SEM) images revealed that LWS-SLNs were spherical and homogeneously dispersed. The average diameter of free SLNs and LWS-SLNs were 97 ± 1.4 and 127 ± 3.1 nm, respectively with high EE% (95.88 ± 3.29) and a DL of 22.72 ± 1.39 mg/mL of LWS-SLNs. The plain LWS could induce growth inhibition of A549 cells with IC₅₀ of 17.99 ± 1.11, 13.37 ± 1.22, and 9.21 ± 1.15 μg/mL after 24, 48, and 72 h, respectively, while LWS-SLNs had more cytotoxic effects after 48 h (9.81 ± 1.3 μg/mL). Comet assay represented clear fragmentation in the chromatin of the treated cells. Besides, LWS-SLNs (13.37 ± 1.22 μg/mL) induced ∼52 % apoptosis and even necrosis after 48 h. The qPCR results showed an enhanced downregulation of Bcl-2 and upregulation of Casp 9 due to the treatment of A549 cells with LSW-SLNs. In conclusion, a stable formulation of LWS-SLN was prepared with good physicochemical features and long-term biological effects that candidate it for in vivo trials.

Probing synergistic interplay between bio-inspired peptidomimetic chitosan-copper complexes and doxorubicin

The current investigation reports a novel and facile method for modification of low molecular weight chitosan (Cs) with guanidine moieties, aimed at enhancing its cellular interaction and thus augmenting its cellular internalization. Guadinylated chitosan-copper (Cs-Gn-Cu) chelates, based on copper-nitrogen co-ordination, were established. Characterization of chelates was conducted using ¹H NMR, ¹³C NMR, XPS, XRD, TGA-DTA, and GPC techniques. Anticancer activity of formed chelates was confirmed against A549 cells using MTT assay. Experimental outcomes, for the first time, have provided an empirical evidence for synergistic interaction between the chelated polymer (Cs-Gn-Cu) and the established anti-cancer agent, Doxorubicin (Dox), based on analysis by the Chou Talalay method and estimation of their combination indices. ROS induction was demonstrated as the mechanism of action of the chelated polymer, which supplemented rapid destruction of cancerous cells by Dox. These findings strongly advocate the need for harnessing unexplored potential of these innovative metal polymer chelates in cases of Dox resistant lung cancer, wherein the polymeric system itself would serve as an anti-cancer agent.

Tuning of endosomal escape and gene expression by functional groups, molecular weight and transfection medium: a structure-activity relationship study

The use of genetic material by non-viral transfer systems is still in its initial stages, but there are high expectations for the development of targeted therapies. However, nucleic acids cannot enter cells without help, they must be well protected to prevent degradation and overcome a variety of biological barriers, the endosomal barrier being one of the greatest cellular challenges. Herein, the structure-property-relationship was investigated in detail, using well-defined polymers. Polyacrylamides were synthesized via RAFT polymerization resulting in a polymer library of (i) different cationic groups as aminoethyl acrylamide (AEAm), dimethylaminoethyl acrylamide (DMAEAm), dimethylaminopropyl acrylamide (DMAPAm) and guanidinopropyl acrylamide (GPAm); (ii) different degree of polymerization; and investigated (iii) in different cell culture settings. The influence of molar mass and cationic moiety on complex formation with pDNA, cytotoxicity and transfection efficiency of the polymers were investigated. The systematic approach identified a pH-independent guanidinium-containing homopolymer (PGPAm₈₉) as the polymer with the highest transfection efficiency and superior endosomal release under optimal conditions. Since PGPAm₈₉ is not further protonated inside endosomes, common escape theories appear unsuitable. Therefore, the interaction with bis(monoacryloylglycerol)phosphate, a lipid specific for endosomal vesicles, was investigated. Our research suggests that the interactions between amines and lipids may be more relevant than anticipated.

Entry of nanoparticles into cells: the importance of nanoparticle properties

Knowledge of the interactions between nanoparticles (NPs) and cell membranes is of great importance for the design of safe and efficient nanomedicines.

Arginine-Based Polymer Brush Coatings with Hydrolysis-Triggered Switchable Functionalities from Antimicrobial (Cationic) to Antifouling (Zwitterionic)

Arginine polymer based coatings with switchable properties were developed on glass slides (GS) to demonstrate the smart transition from antimicrobial (cationic) to fouling-resistant (zwitterionic) surfaces. l-Arginine methyl ester-methacryloylamide (Arg-Est) and l-arginine-methacryloylamide (Arg-Me) polymer brushes were grafted from the GS surface via surface-initiated reversible addition-fragmentation chain-transfer (SI-RAFT) polymerization. In comparison to the pristine GS and Arg-Me graft polymerized GS (GS-Arg-Me) surfaces, the Arg-Est polymer brushes-functionalized GS surfaces exhibit a superior antimicrobial activity. Upon hydrolysis treatment, the strong bactericidal efficacy switches to good resistance to adsorption of bovine serum albumin (BSA), the adhesion of Gram-positive bacteria Staphylococcus aureus and Gram-negative bacteria Escherichia coli, as well as the attachment of Amphora coffeaeformis. In addition, the switchable coatings are proven to be biocompatible. The stability and durability of the switchable coatings are also ascertained after exposure to filtered seawater for 30 days. Therefore, deposition of the proposed "smart coatings" offers another environmentally friendly alternative for combating biofouling.

A stimuli-responsive methionine-based zwitterionic methacryloyl sulfonium sulfonate monomer and the corresponding antifouling polymer with tunable thermosensitivity

This report describes a dual pH- and thermo-responsive methionine-based zwitterionic methacryloyl sulfonium sulfonate monomer and the corresponding zwitterionic antifouling polymer with ion-induced tunable thermosensitivity.

Metal-containing and related polymers for biomedical applications

A survey of the most recent progress in the biomedical applications of metal-containing polymers is given. Due to the unique optical, electrochemical, and magnetic properties, at least 30 different metal elements, most of them transition metals, are introduced into polymeric frameworks for interactions with biology-relevant substrates via various means. Inspired by the advance of metal-containing small molecular drugs and promoted by the great progress in polymer chemistry, metal-containing polymers have gained momentum during recent decades. According to their different applications, this review summarizes the following biomedical applications: (1) metal-containing polymers as drug delivery vehicles; (2) metal-containing polymeric drugs and biocides, including antimicrobial and antiviral agents, anticancer drugs, photodynamic therapy agents, radiotherapy agents and biocides; (3) metal-containing polymers as biosensors, and (4) metal-containing polymers in bioimaging.

Bio-inspired cisplatin nanocarriers for osteosarcoma treatment

Cisplatin nanocarriers with zwitterionic phosphorylcholine corona were developed for osteosarcoma treatment.