Epsilon-poly-L-lysine: Recent Advances in Biomanufacturing and Applications
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ABSTRACT:
SUBMITTER: Wang L
PROVIDER: S-EPMC8506220 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Poly(?-l-lysine) (PLL) is a class of water-soluble, cationic biopolymer composed of ?-l-lysine structural units. The previous decade witnessed tremendous progress in the synthesis and biomedical applications of PLL and its composites. PLL-based polymers and copolymers, till date, have been extensively explored in the contexts such as antibacterial agents, gene/drug/protein delivery systems, bio-sensing, bio-imaging, and tissue engineering. This review aims to summarize the recent advances in PLL-based nanomaterials in these biomedical fields over the last decade. The review first describes the synthesis of PLL and its derivatives, followed by the main text of their recent biomedical applications and translational studies. Finally, the challenges and perspectives of PLL-based nanomaterials in biomedical fields are addressed.
| S-EPMC7744653 | biostudies-literature
Project description:PurposeTo determine the amoebicidal activity of functionalized poly-epsilon-lysine hydrogels (pɛK+) against Acanthamoeba castellanii.MethodsA. castellanii trophozoites and cysts were grown in the presence of pɛK solution (0-2.17 mM), pɛK or pɛK+ hydrogels, or commercial hydrogel contact lens (CL) for 24 hours or 7 days in PBS or Peptone-Yeast-Glucose (PYG) media (nutrient-deplete or nutrient-replete cultures, respectively). Toxicity was determined using propidium iodide and imaged using fluorescence microscopy. Ex vivo porcine corneas were inoculated with A. castellanii trophozoites ± pɛK, pɛK+ hydrogels or commercial hydrogel CL for 7 days. Corneal infection was assessed by periodic acid-Schiff staining and histologic analysis. Regrowth of A. castellanii from hydrogel lenses and corneal discs at 7 days was assessed using microscopy and enumeration.ResultsThe toxicity of pɛK+ hydrogels resulted in the death of 98.52% or 83.31% of the trophozoites at 24 hours or 7 days, respectively. The toxicity of pɛK+ hydrogels resulted in the death of 70.59% or 82.32% of the cysts in PBS at 24 hours or 7 days, respectively. Cysts exposed to pɛK+ hydrogels in PYG medium resulted in 75.37% and 87.14% death at 24 hours and 7 days. Ex vivo corneas infected with trophozoites and incubated with pɛK+ hydrogels showed the absence of A. castellanii in the stroma, with no regrowth from corneas or pɛK+ hydrogel, compared with infected-only corneas and those incubated in presence of commercial hydrogel CL.ConclusionspɛK+ hydrogels demonstrated pronounced amoebicidal and cysticidal activity against A. castellanii. pɛK+ hydrogels have the potential for use as CLs that could minimize the risk of CL-associated Acanthamoeba keratitis.
| S-EPMC8742527 | biostudies-literature
Project description:ε-Poly-lysine (ε-PL) is an uncommon cationic, naturally-occurring homopolymer produced by the fermentation process. Due to its significant antimicrobial activity and nontoxicity to humans, ε-PL is now industrially produced as an additive, e.g. for food and cosmetics. However, the biosynthetic route can only make polymers with a molecular weight of about 3 kDa. Here, we report a new chemical strategy based on ring-opening polymerization (ROP) to obtain ε-PL from lysine. The 2,5-dimethylpyrrole protected α-amino-ε-caprolactam monomer was prepared through cyclization of lysine followed by protection. ROP of this monomer, followed by the removal of the protecting group, 2,5-dimethylpyrrole, ultimately yielded ε-PL with varying molecular weights. The structure of this chemosynthetic ε-PL has been fully characterized by 1H NMR, 13C NMR, and MALDI-TOF MS analyses. This chemosynthetic ε-PL exhibited a similar pKa value and low cytotoxicity as the biosynthetic analogue. Using this new chemical strategy involving ROP without the need for phosgene may enable a more cost effective production of ε-PL on a larger-scale, facilitating the design of more advanced biomaterials.
| S-EPMC6054053 | biostudies-literature
Project description:ε-Poly-L-lysine (ε-PL) is a natural amino acid polymer produced by microbial fermentation. It has been mainly used as a preservative in the food and cosmetics industries, as a drug carrier in medicines, and as a gene carrier in gene therapy. ε-PL synthase is the key enzyme responsible for the polymerization of L-lysine to form ε-PL. In this study, the ε-PL synthase gene was overexpressed in Streptomyces albulus CICC 11022 by using the kasOp∗ promoter and the ribosome binding site from the capsid protein of phage ϕC31, which resulted in a genetically engineered strain Q-PL2. The titers of ε-PL produced by Q-PL2 were 88.2% ± 8.3% higher than that produced by the wild strain in shake flask fermentation. With the synergistic effect of 2 g/L sodium citrate, the titers of ε-PL produced by Q-PL2 were 211.2% ± 17.4% higher than that produced by the wild strain. In fed-batch fermentations, 20.1 ± 1.3 g/L of ε-PL was produced by S. albulus Q-PL2 in 72 h with a productivity of 6.7 ± 0.4 g/L/day, which was 3.2 ± 0.3-fold of that produced by the wild strain. These results indicate that ε-PL synthase is one of the rate-limiting enzymes in ε-PL synthesis pathway and lays a foundation for further improving the ε-PL production ability of S. albulus by metabolic engineering.
| S-EPMC7188835 | biostudies-literature
Project description:Epsilon-poly-L-lysine (epsilon-PL) is produced by Streptomyces albulus NBRC14147 as a secondary metabolite and can be detected only when the fermentation broth has an acidic pH during the stationary growth phase. Since strain NBRC14147 produces epsilon-PL-degrading enzymes, the original chain length of the epsilon-PL polymer product synthesized by epsilon-PL synthetase (Pls) is unclear. Here, we report on the identification of the gene encoding the epsilon-PL-degrading enzyme (PldII), which plays a central role in epsilon-PL degradation in this strain. A knockout mutant of the pldII gene was found to produce an epsilon-PL of unchanged polymer chain length, demonstrating that the length is not determined by epsilon-PL-degrading enzymes but rather by Pls itself and that the 25 to 35 L-lysine residues of epsilon-PL represent the original chain length of the polymer product synthesized by Pls in vivo. Transcriptional analysis of pls and a kinetic study of Pls further suggested that the Pls catalytic function is regulated by intracellular ATP, high levels of which are required for full enzymatic activity. Furthermore, it was found that acidic pH conditions during epsilon-PL fermentation, rather than the inhibition of the epsilon-PL-degrading enzyme, are necessary for the accumulation of intracellular ATP.
| S-EPMC2935060 | biostudies-literature
Project description:The extracellular matrix (ECM) is a three-dimensional network within which fundamental cell processes such as cell attachment, proliferation, and differentiation occur driven by its inherent biological and structural cues. Hydrogels have been used as biomaterials as they possess many of the ECM characteristics that control cellular processes. However, the permanent crosslinking often found in hydrogels fails to recapitulate the dynamic nature of the natural ECM. This not only hinders natural cellular migration but must also limit cellular expansion and growth. Moreover, there is an increased interest in the use of new biopolymers to create biomimetic materials that can be used for biomedical applications. Here we report on the natural polymer poly-ε-lysine in forming dynamic hydrogels via reversible imine bond formation, with cell attachment promoted by arginine-glycine-aspartic acid (RGD) incorporation. Together, the mechanical properties and cell behavior of the dynamic hydrogels with low poly-ε-lysine quantities indicated good cell viability and high metabolic activity.
| S-EPMC7504584 | biostudies-literature
Project description:Antibiotic resistance is a big threat to public health. How to improve the therapeutic efficacy of conventional antibiotics is an effective way to address this issue. In order to enhance the antibacterial activity of conventional antibiotic erythromycin (EM), EM is conjugated to positively charged ε-poly-l-lysine (EPL) to obtain EPL modified EM (EPL-EM). The grafting ratio of EM can be calculated from the 1H NMR spectrum. EPL-EM is stable in physiological environment, while EM can be readily released from EPL-EM upon incubating with esterase which can be secreted by most bacteria. Because of the presence of cationic EPL, EPL-EM showed much stronger antibacterial activity than free EM, with much lower minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Moreover, compared to free EM, the development of drug resistance can be slowed down if EPL-EM is used, which can be ascribed to the reduction of EM dosage. Meanwhile, EPL-EM cannot induce hemolysis and cytotoxicity, which indicates that EPL-EM exhibits excellent biocompatibility. The design of EPL-EM with enhanced antibacterial activity and excellent biocompatibility provides an innovative way to combat antibiotic resistance.
| S-EPMC10280332 | biostudies-literature
Project description:Epsilon-poly-l-lysine (ε-PL) is a natural antimicrobial cationic peptide which is generally regarded as safe (GRAS) as a food preservative. Although its antimicrobial activity is well documented, its mechanism of action is only vaguely described. The aim of this study was to clarify ε-PL's mechanism of action using Escherichia coli and Listeria innocua as model organisms. We examined ε-PL's effect on cell morphology and membrane integrity and used an array of E. coli deletion mutants to study how specific outer membrane components affected the action of ε-PL. We furthermore studied its interaction with lipid bilayers using membrane models. In vitro cell studies indicated that divalent cations and the heptose I and II phosphate groups in the lipopolysaccharide layer of E. coli are critical for ε-PL's binding efficiency. ε-PL removed the lipopolysaccharide layer and affected cell morphology of E. coli, while L. innocua underwent minor morphological changes. Propidium iodide staining showed that ε-PL permeabilized the cytoplasmic membrane in both species, indicating the membrane as the site of attack. We compared the interaction with neutral or negatively charged membrane systems and showed that the interaction with ε-PL relied on negative charges on the membrane. Suspended membrane vesicles were disrupted by ε-PL, and a detergent-like disruption of E. coli membrane was confirmed by atomic force microscopy imaging of supported lipid bilayers. We hypothesize that ε-PL destabilizes membranes in a carpet-like mechanism by interacting with negatively charged phospholipid head groups, which displace divalent cations and enforce a negative curvature folding on membranes that leads to formation of vesicles/micelles.
| S-EPMC4249222 | biostudies-literature
Project description:Titanium dioxide (TiO2) nanostructures are one of the most plentiful compounds that have emerged in various fields of technology such as medicine, energy and biosensing. Various TiO2 nanostructures (nanotubes [NTs] and nanowires) have been employed in photoelectrochemical (PEC) biosensing applications, greatly enhancing the detection of targets. TiO2 nanostructures, used as reinforced material or coatings for the bare surface of titanium implants, are excellent additive materials to compensate titanium implants deficiencies-like poor surface interaction with surrounding tissues-by providing nanoporous surfaces and hierarchical structures. These nanostructures can also be loaded by diversified drugs-like osteoporosis drugs, anticancer and antibiotics-and used as local drug delivery systems. Furthermore, TiO2 nanostructures and their derivatives are new emerging antimicrobial agents to overcome human pathogenic microorganisms. However, like all other nanomaterials, toxicity and biocompatibility of TiO2 nanostructures must be considered. This review highlights recent advances, along with the properties and numerous applications of TiO2-based nanostructure compounds in nano biosensing, medical implants, drug delivery and antibacterial fields. Moreover, in the present study, some recent advances accomplished on the pharmaceutical applications of TiO2 nanostructures, as well as its toxicity and biocompatibility, are presented.
| S-EPMC7234979 | biostudies-literature
Project description:Purpose:To determine the antimicrobial activity of poly-epsilon-lysine (p?K) functionalization of hydrogels against Pseudomonas aeruginosa. Methods:Antimicrobial activities of p?K and p?K+ hydrogels were tested against both keratitis and a laboratory strain of Paeruginosa at a range of inocula sizes, over 4 and 24 hours. The number of viable CFU on p?K and p?K+ hydrogels or commercial contact lenses (CL) was investigated. Ex vivo porcine corneas were inoculated with Paeruginosa PAO1 (103 CFU) and incubated with p?K+ hydrogels or commercial hydrogel CL for 24 hours and the effects of infection determined. Results:P?K+ hydrogels showed log reductions in viable CFU compared with p?K hydrogels for all Paeruginosa strains, depending on inocula sizes and incubation time. After 24 hours p?K+ hydrogels showed >5 and >7.5 log reduction in CFU compared with commercial hydrogel CL at 103 and 106 CFU, respectively. In an ex vivo porcine corneal infection model, p?K+ hydrogels led to a significant decrease in viable PAO1 CFU and histologic analysis indicated a decreased infiltration of PAO1 into the stroma. Conclusions:P?K+ hydrogels demonstrated enhanced antimicrobial activity versus nonfunctionalized p?K hydrogels against clinically relevant Paeruginosa strains. P?K+ hydrogels have the potential to be used as a bandage CL with innate antimicrobial characteristics to minimize the risk of microbial keratitis.
| S-EPMC7441358 | biostudies-literature