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International Journal of Biological... May 2022The design of multifunctional hydrogels based on bioactive hyaluronic acid (HA) and antibacterial cationic polymer ɛ-poly-l-lysine (ε-PL) is a promising tool in tissue...
The design of multifunctional hydrogels based on bioactive hyaluronic acid (HA) and antibacterial cationic polymer ɛ-poly-l-lysine (ε-PL) is a promising tool in tissue engineering applications. In the current study, we have designed hyaluronic acid and ɛ-polylysine composite hydrogel systems with antibacterial and cell attractive properties. Two distinct crosslinking approaches were used: the physical crosslinking based on electrostatic attractions and the chemical crosslinking of charged functional groups (-NH and -COOH). The impact of the crosslinking strategy on fabricated hydrogel molecular structure, swelling behavior, gel fraction, morphology, porosity, viscoelastic properties, antibacterial activity, and in vitro biocompatibility was evaluated. Both chemically and physically crosslinked HA/ԑ-PL hydrogels demonstrated fast swelling behavior and long-term stability for at least 28 days, as well as similar order of stiffness (10-30 kPa). We demonstrated that physically crosslinked hydrogels inhibited over 99.999% of Gram-negative E. coli, while chemically crosslinking strategy led to the antibacterial efficiency decrease. However, cell viability was significantly improved, confirming the importance of the applied crosslinking approach to the antibacterial activity and in vitro biocompatibility. The distinct differences in the physicochemical and biological properties of the developed materials provide new opportunities to design next-generation functional composite hydrogel systems.
Topics: Anti-Bacterial Agents; Escherichia coli; Hyaluronic Acid; Hydrogels; Polylysine
PubMed: 35378161
DOI: 10.1016/j.ijbiomac.2022.03.207 -
Food & Function Apr 2022This study aimed to assess the influence of dietary supplementation of ε-polylysine on the gut microbiota and host nutrient metabolism, which is not systematically...
This study aimed to assess the influence of dietary supplementation of ε-polylysine on the gut microbiota and host nutrient metabolism, which is not systematically discussed by multi-omics analysis. A total of 40 mice were randomly divided into two groups exposed to either a basal diet (AIN-76A) or a basal diet with 150 ppm ε-polylysine. Fecal samples were collected for gut bacteria identification. Liver and plasma samples were collected for metabolomic and proteomic analyses. The results showed that ε-polylysine decreased the body weight of mice and affected the presence of certain types of intestinal microorganisms. The richness of the microbiota and number of phyla increased with age. ε-Polylysine affected the presence of genera and species, and either regulated or took part in the metabolism of energy, nitrogen, amino acids, lipids, carbohydrates, glycans, cofactors, and vitamins. The metabolite profiling showed that lipid and lipid-like molecules metabolites occupied the majority percent of plasma and liver metabolites. Additionally, ε-polylysine regulated the key role of metabolites and related metabolic enzymes in the metabolic pathways, especially phospholipid metabolism. In conclusion, dietary ε-polylysine improved the immunity of growing mice, and had a greater effect on the anabolism of nutrients in adult mice.
Topics: Animals; Diet; Gastrointestinal Microbiome; Lipid Metabolism; Mice; Polylysine; Proteomics
PubMed: 35315841
DOI: 10.1039/d1fo04227k -
Biomacromolecules Aug 2022In enzymatic active sites, the essential functional groups are spatially arranged as a result of the enzyme three-dimensional folding, which leads to remarkable...
Enzyme-Mimicking Materials from Designed Self-Assembly of Lysine-Rich Peptides and G-Quadruplex DNA/Hemin DNAzyme: Charge Effect of the Key Residues on the Catalytic Functions.
In enzymatic active sites, the essential functional groups are spatially arranged as a result of the enzyme three-dimensional folding, which leads to remarkable catalytic properties. We are inspired to self-assemble the polylysine peptides with guanine-rich DNA and hemin as cofactor to fabricate the peroxidase-mimicking catalytic nanomaterials. The DNA can fold into G-quadruplex to provide a supramolecular scaffold and a nucleobase for supporting and coordinating hemin, and the polylysine provides amine as distal groups to promote the HO adsorption to the iron of hemin. The polylysine and DNA components synergistically accelerated the hemin-catalyzed reactions, and the complex containing ε-polylysine exhibited higher activity than α-polylysine. This activity difference is attributed to the higher p value and more susceptible protonation of amine of ε-polylysine than α-polylysine. The ε-polylysine/DNA/hemin had similar coordination states of hemin and conformations of the components to α-polylysine/DNA/hemin but accelerated the formation of the intermediate compound I faster than α-polylysine. Theoretical simulation reveals that the unprotonated NH behaved like a base catalyst, similar to His-42 residue in the natural heme pocket, while the protonated NH acted as an acid, which indicated that the base catalyst on the distal side of the hemin pocket is more active than the acid. This work provides an avenue to control the distribution of the catalytic residues in an enzyme-like active site and to understand the roles of the key residues of native enzymes.
Topics: Amines; Biosensing Techniques; Catalysis; DNA; DNA, Catalytic; G-Quadruplexes; Hemin; Hydrogen Peroxide; Peptides; Polylysine
PubMed: 35901109
DOI: 10.1021/acs.biomac.2c00620 -
ACS Applied Bio Materials May 2021Developing strategies to optimize double-stranded RNA (dsRNA) delivery remains a significant challenge in improving RNA interference (RNAi) in insects. Nanoformulations...
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 (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 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 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 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.
Topics: Animals; Biocompatible Materials; Catechin; Gene Silencing; Materials Testing; Nanoparticles; Particle Size; Polylysine; RNA, Double-Stranded; Spodoptera
PubMed: 35006843
DOI: 10.1021/acsabm.1c00109 -
Journal of Pharmaceutical Sciences Sep 2020Activation of the immune system to treat cancer has emerged as a powerful therapy tool, however, treatments must overcome the immunosuppressive microenvironment...
Activation of the immune system to treat cancer has emerged as a powerful therapy tool, however, treatments must overcome the immunosuppressive microenvironment established by tumors. Toll-like receptor (TLR) agonists like CpG and polyI:C are potent stimulators of non-specific, pro-inflammatory immune responses, targeting TLR9 and TLR3, respectively. While these immunostimulants seem promising, systemic exposure can eventually induce severe side effects. Adverse inflammatory reactions in healthy tissues may be avoided by delivering and retaining immunostimulants in proximity to tumors or to primary sites of tumor metastases. Immunostimulants such as CpG and polyI:C cannot be completely immobilized, however, since the target TLR9 and TLR3 are located intracellularly. Previously, polycations like poly-l-lysine (PLL) have been complexed to the anionic CpG or polyI:C with the purpose of improving intracellular delivery and potency. Here, the relationship between PLL molecular weight and immunostimulant complexation, TLR activation, and transport in a simple, model tumor microenvironment was investigated. The polyplexes could be formulated to dramatically limit immunostimulant transport suggesting the potential for injection site retention and minimized systemic exposure of immunostimulants. The molecular weight of PLL and ratio of PLL to immunostimulant affected the accessibility of the immunostimulant within the polyplex and polyplex interaction strength.
Topics: Adjuvants, Immunologic; Humans; Neoplasms; Polylysine; Toll-Like Receptors; Tumor Microenvironment
PubMed: 32565351
DOI: 10.1016/j.xphs.2020.06.009 -
Biomaterials Science Dec 2020Infections related to implanted medical devices have placed a heavy burden on public health and require feasible solutions. In this study, a simple approach is reported...
Infections related to implanted medical devices have placed a heavy burden on public health and require feasible solutions. In this study, a simple approach is reported to fabricate an antifouling and antibacterial dual-functional coating. One-step aqueous supramolecular assembly of bovine serum albumin (BSA) is employed to immobilize ε-polylysine (ε-PL) and form a coating (PTB@ε-PL). Based on amyloid-like protein aggregation through the rapid reduction of the intramolecular disulfide bonds of BSA by tris(2-carboxyethyl) phosphine, a dense PTB@ε-PL nanofilm with controllable thickness and ε-PL loading density can be covered on virtually arbitrary material surfaces by simple aqueous dipping. In vitro and in vivo experiments show that this coating not only exhibits effective antibacterial activity against Gram-positive/Gram-negative bacteria, but also imparts excellent antifouling property to the surface. As a pure biopolymer coating, the PTB@ε-PL nanofilm shows negligible cytotoxicity and hemolysis. In addition, due to the various functional groups exposed on the surface of the nanofilm, the coating shows excellent interfacial bonding stability and can maintain bactericidal and antifouling properties under harsh conditions including ultrasound, autoclaving, organic solvents, and physiological body fluids.
Topics: Anti-Bacterial Agents; Anti-Infective Agents; Polylysine; Protein Aggregates; Serum Albumin, Bovine
PubMed: 32691767
DOI: 10.1039/d0bm00760a -
International Journal of Biological... Mar 2024ε-Poly-l-lysine (ε-PL) is a natural homo-poly(amino acid) which can be produced by microorganisms. With the advantages in broad-spectrum antimicrobial activity,... (Review)
Review
ε-Poly-l-lysine (ε-PL) is a natural homo-poly(amino acid) which can be produced by microorganisms. With the advantages in broad-spectrum antimicrobial activity, biodegradability, and biocompatibility, ε-PL has been widely used as a preservative in the food industry. Different molecular architectures endow ε-PL and ε-PL-based materials with versatile applications. However, the microbial synthesis of ε-PL is currently limited by low efficiencies in genetic engineering and molecular architecture modification. This review presents recent advances in ε-PL production and molecular architecture modification of microbial ε-PL, with a focus on the current challenges and solutions for the improvement of the productivity and diversity of ε-PL. In addition, we highlight recent examples where ε-PL has been applied to expand the versability of edible films and nanoparticles in various applications. Commercial production and the challenges and future research directions in ε-PL biosynthesis are also discussed. Currently, although the main use of ε-PL is as a food preservative, ε-PL and ε-PL-based polymers have shown excellent application potential in biomedical fields. With the development of synthetic biology, the design and synthesis of ε-PL with a customized molecular architecture are possible in the near future. ε-PL-based polymers with specific functions will be a new trend in biopolymer manufacturing.
Topics: Polylysine; Streptomyces; Fermentation; Amino Acids; Polymers
PubMed: 38262828
DOI: 10.1016/j.ijbiomac.2024.129513 -
Biomaterials Science Mar 2021New generation antimicrobial agents are expected to exhibit non-metabolic killing mechanisms, high killing potency and biocompatibility. We synthesized a cationic...
New generation antimicrobial agents are expected to exhibit non-metabolic killing mechanisms, high killing potency and biocompatibility. We synthesized a cationic chitosan derivative and an anionic chitosan derivative - specifically an α-poly(l)lysine side-grafted chitosan (CS-PLL) and an anionic citraconyl anhydride (CA) modified polylysine side graft for chitosan (CS-PLL-CA). The β-carboxylic amide of CS-PLL-CA is pH-labile and self-cleavable under pH 6 or below. When we mixed the cationic (CS-PLL) and anionic (CS-PLL-CA) peptidosaccharide copolymers, they self-assembled, due to electrostatic charge interactions, into nanomicelles (NMs) with the oppositely charged peptides in the core and the chitosan polysaccharide arms on the shell. The NMs exhibited high hemo- and cytocompatibility (nontoxic) at physiological pH of 7.4, due to the chitosan protection on the shell and charge neutralization on the core. Upon reaching the bacterial infection site, the chitosan shell interacted and accumulated around the bacteria. The bacterial infection sites in the body usually show localized acidity as a result of the combined actions of bacterial metabolism and host immune response, and the pH can decrease to as low as 5.5. At this low pH, the β-carboxylic amide bond of the anionic polypeptide gradually hydrolyzed to expose the initial cationic amine moieties, causing the NMs to 'decompose' into individual CS-PLL and 'spill' the cationic molecules which then disrupted and killed the bacteria. This 'smart' bacteria-recognizing chitosan-decorated nanosystem opens the pathway to explore other anionic and cationic and biocompatible polymers for 'stealth' delivery of antimicrobial polypeptide, and 'on-demand' recovery of the cationic parts to kill bacteria at infection sites.
Topics: Anti-Bacterial Agents; Anti-Infective Agents; Bacterial Infections; Chitosan; Humans; Polylysine
PubMed: 33410824
DOI: 10.1039/d0bm01382j -
Journal of Food Protection Jul 2023The purpose of the study was to investigate the mechanism of inactivation of Serratia liquefaciens by different treatments, namely corona discharge plasma (CDP),...
The purpose of the study was to investigate the mechanism of inactivation of Serratia liquefaciens by different treatments, namely corona discharge plasma (CDP), ε-polylysine (ε-PL), and corona discharge plasma combined with ε-polylysine (CDP plus ε-PL). The results showed that the combined treatment of CDP and ε-PL exhibited significant antibacterial effects. The total number of colonies of S. liquefaciens dropped by 0.49 log CFU/mL following 4 min of CDP treatment, 4MIC ε-PL treatment for 6 h alone decreased the amounts of colonies by 2.11 log CFU/mL, and 6 h of treatment with 4MIC ε-PL after the bacterium was treated with CDP could decrease the number of colonies by 6.77 log CFU/mL. Scanning electron microscopy images showed that the combined treatment of CDP and ε-PL caused the most serious damage to the cell morphology. Electrical conductivity, nucleic acid, and PI staining indicated that the combined treatment dramatically enhanced the permeability of the cell membrane. In addition, the combined treatment led to a significant decrease in SOD and POD enzyme activities in S. liquefaciens, which prevented energy metabolism. Finally, the determination of free and intracellular ε-PL concentrations confirmed that the treatment of CDP could cause the bacteria to bind more ε-PL and exert more significant bacterial inhibition. Therefore, CDP and ε-PL had a synergistic effect in the inhibition of S. liquefaciens.
Topics: Polylysine; Serratia liquefaciens; Anti-Bacterial Agents; Cell Membrane; Microscopy, Electron, Scanning
PubMed: 37295216
DOI: 10.1016/j.jfp.2023.100078 -
Journal of Food Protection Jul 2024Salmonella is capable of surviving dehydration within various foods, such as dried fruit. Dried fruit, including apple slices, have been the subject of product recalls...
Salmonella is capable of surviving dehydration within various foods, such as dried fruit. Dried fruit, including apple slices, have been the subject of product recalls due to contamination with Salmonella. A study was conducted to determine the fate of Salmonella on apple slices, following immersion in three antimicrobial solutions (viz., ε-polylysine [epsilon-polylysine or EP], sodium bisulfate [SBS], or peracetic acid [PAA]), and subsequent hot air dehydration. Gala apples were aseptically cored and sliced into 0.4 cm thick rings, bisected, and inoculated with a five-strain composite of desiccation-resistant Salmonella, to a population of 8.28 log CFU/slice. Slices were then immersed for 2 min in various concentrations of antimicrobial solutions, including EP (0.005, 0.02, 0.05, and 0.1%), SBS (0.05, 0.1, 0.2, and 0.3%), PAA (18 or 42 ppm), or varying concentrations of PAA + EP, and then dehydrated at 60°C for 5 h. Salmonella populations in positive control samples (inoculated apple slices washed in sterile water) declined by 2.64 log after drying. In the present study, the inactivation of Salmonella, following EP and SBS treatments, increased with increasing concentrations, with maximum reductions of 3.87 and 6.20 log (with 0.1 and 0.3% of the two compounds, respectively). Based on preliminary studies, EP concentrations greater than 0.1% did not result in lower populations of Salmonella. Pretreatment washes with either 18 or 42 ppm of PAA inactivated Salmonella populations by 4.62 and 5.63 log, respectively, following desiccation. Combining PAA with up to 0.1% EP induced no greater population reductions of Salmonella than washing with PAA alone. The addition of EP to PAA solutions appeared to destabilize PAA concentrations, reducing its biocidal efficacy. These results may provide antimicrobial predrying treatment alternatives to promote the reduction of Salmonella during commercial or consumer hot air drying of apple slices.
Topics: Malus; Peracetic Acid; Salmonella; Polylysine; Food Microbiology; Humans; Colony Count, Microbial; Sulfates; Food Preservation; Dose-Response Relationship, Drug; Desiccation; Food Contamination; Food Handling; Consumer Product Safety
PubMed: 38734414
DOI: 10.1016/j.jfp.2024.100297