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The Analyst Jul 2014Spatially organised neuronal networks have wide reaching applications, including fundamental research, toxicology testing, pharmaceutical screening and the realisation...
Spatially organised neuronal networks have wide reaching applications, including fundamental research, toxicology testing, pharmaceutical screening and the realisation of neuronal implant interfaces. Despite the large number of methods catalogued in the literature there remains the need to identify a method that delivers high pattern compliance, long-term stability and is widely accessible to neuroscientists. In this comparative study, aminated (polylysine/polyornithine and aminosilanes) and cytophobic (poly(ethylene glycol) (PEG) and methylated) material contrasts were evaluated. Backfilling plasma stencilled PEGylated substrates with polylysine does not produce good material contrasts, whereas polylysine patterned on methylated substrates becomes mobilised by agents in the cell culture media which results in rapid pattern decay. Aminosilanes, polylysine substitutes, are prone to hydrolysis and the chemistries prove challenging to master. Instead, the stable coupling between polylysine and PLL-g-PEG can be exploited: Microcontact printing polylysine onto a PLL-g-PEG coated glass substrate provides a simple means to produce microstructured networks of primary neurons that have superior pattern compliance during long term (>1 month) culture.
Topics: Amination; Animals; Biocompatible Materials; Cells, Cultured; Glass; Methylation; Mice, Inbred C57BL; Nerve Net; Neurons; Peptides; Polyethylene Glycols; Polylysine; Silanes; Surface Properties; Tissue Array Analysis
PubMed: 24855658
DOI: 10.1039/c4an00608a -
Angewandte Chemie (International Ed. in... Sep 2019In nature, dynamic processes are ubiquitous and often characterized by adaptive, transient behavior. Herein, we present the development of a transient bowl-shaped... (Review)
Review
In nature, dynamic processes are ubiquitous and often characterized by adaptive, transient behavior. Herein, we present the development of a transient bowl-shaped nanoreactor system, or stomatocyte, the properties of which are mediated by molecular interactions. In a stepwise fashion, we couple motility to a dynamic process, which is maintained by transient events; namely, binding and unbinding of adenosine triphosphate (ATP). The surface of the nanosystem is decorated with polylysine (PLL), and regulation is achieved by addition of ATP. The dynamic interaction between PLL and ATP leads to an increase in the hydrophobicity of the PLL-ATP complex and subsequently to a collapse of the polymer; this causes a narrowing of the opening of the stomatocytes. The presence of the apyrase, which hydrolyzes ATP, leads to a decrease of the ATP concentration, decomplexation of PLL, and reopening of the stomatocyte. The competition between ATP input and consumption gives rise to a transient state that is controlled by the out-of-equilibrium process.
Topics: Adenosine Triphosphate; Animals; Artificial Cells; Cell Shape; Erythrocytes; Humans; Hydrophobic and Hydrophilic Interactions; Nanostructures; Nanotechnology; Polylysine
PubMed: 31267638
DOI: 10.1002/anie.201906331 -
Journal of Biomaterials Science.... 2015Polylysine is an important class of polyamino acids with a broad spectrum of applications in biomedical research and development. It can be divided into two classes,... (Review)
Review
Polylysine is an important class of polyamino acids with a broad spectrum of applications in biomedical research and development. It can be divided into two classes, α-polylysine and ε-polylysine, the former is synthesized by artificial chemical synthesis and has limited applications due to its high toxicity, and the latter is produced by microbial synthesis as a class of natural polymers and is widely used in various food, medicinal, and electronics products. Another major class of synthetic polymers is dendrimers (after linear, cross-linked, and branched polymers). Dendrigraft poly-L-lysine (DGL) has the favorable properties of polylysine and dendrimers, with a broad spectrum of applications in drug discovery and development, including drug delivery, gene carriers, diagnostic imaging, diagnostics, biosensors, and special cancer therapies (such as boron neutron capture therapy and photodynamic therapy). As there are still some problems with the development of DGL, further research is warranted for its broad applications.
Topics: Animals; Dendrimers; Humans; Polylysine
PubMed: 26381379
DOI: 10.1080/09205063.2015.1095023 -
Molecular Pharmaceutics Oct 2021Polylysine and materials that integrate lysine form promising drug delivery platforms. As a cationic macromolecule, a polylysine polymer electrostatically interacts with... (Review)
Review
Polylysine and materials that integrate lysine form promising drug delivery platforms. As a cationic macromolecule, a polylysine polymer electrostatically interacts with cells and is efficiently internalized, thereby enabling intracellular delivery. Although polylysine is intrinsically pH-responsive, the conjugation with different functional groups imparts smart, stimuli-responsive traits by adding pH-, temperature-, hypoxia-, redox-, and enzyme-responsive features for enhanced delivery of therapeutic agents. Because of such characteristics, polylysine has been used to deliver various cargos such as small-molecule drugs, genes, proteins, and imaging agents. Furthermore, modifying contrast agents with polylysine has been shown to improve performance, including increasing cellular uptake and stability. In this review, the use of lysine residues, peptides, and polymers in various drug delivery systems has been discussed comprehensively to provide insight into the design and robust manufacturing of lysine-based delivery platforms.
Topics: Drug Delivery Systems; Humans; Lysine; Polylysine
PubMed: 34519501
DOI: 10.1021/acs.molpharmaceut.1c00474 -
Angewandte Chemie (International Ed. in... Apr 2016Peptide-decorated dendrimers (PDDs) are a class of spherical, regular, branched polymers that are modified by peptides covalently attached to their surface. PDDs have... (Review)
Review
Peptide-decorated dendrimers (PDDs) are a class of spherical, regular, branched polymers that are modified by peptides covalently attached to their surface. PDDs have been used as protein mimetics, novel biomaterials, and in a wide range of biomedical applications. Since their design and development in the late eighties, poly-l-lysine has been a preferred core structure for PDDs. However, numerous recent innovations in polymer synthesis and ligation chemistry have re-energized the field and led to the emergence of well-defined peptide dendrimers with more diverse core structures and functions. This Minireview highlights the development of PDDs driven by significantly improved ligation chemistry incorporating structurally well-defined peptides and the emerging use of PDDs in imaging and drug development.
Topics: Animals; Biocompatible Materials; Biomimetic Materials; Chemistry Techniques, Synthetic; Dendrimers; Drug Carriers; Drug Delivery Systems; Gene Transfer Techniques; Humans; Models, Molecular; Optical Imaging; Peptides; Polylysine; Radionuclide Imaging
PubMed: 26990715
DOI: 10.1002/anie.201508428 -
The Urologic Clinics of North America Nov 2020Relatively simple, synthetic, double-stranded RNAs can be powerful viral pathogen-associated molecular pattern (PAMP) mimics, inducing a panoply of antiviral and... (Review)
Review
Relatively simple, synthetic, double-stranded RNAs can be powerful viral pathogen-associated molecular pattern (PAMP) mimics, inducing a panoply of antiviral and antitumor responses that act at multiple stages of host defense. Their mechanisms of action and uses are beginning to be understood, alone, in combination with other therapeutics, or as novel PAMP-adjuvants providing the critical danger signal that has been missing from most cancer and other modern vaccines. Dose, timing, route of administration combinations, and other clinical variables can have a critical impact on immunogenicity. This article reviews advances in the use of polyinosinic-polycytidylic acid and derivatives, in particular poly-ICLC.
Topics: Adjuvants, Immunologic; Cancer Vaccines; Carboxymethylcellulose Sodium; Clinical Trials as Topic; Humans; Immunologic Factors; Male; Pathogen-Associated Molecular Pattern Molecules; Poly I-C; Polylysine; Prostatic Neoplasms; RNA, Double-Stranded
PubMed: 33446322
DOI: 10.1016/j.ucl.2020.10.003 -
Biomaterials Science Jun 2024The treatment of various types of wounds such as dermal wounds, multidrug resistant bacteria-infected wounds, and chronic diabetic wounds is one of the critical... (Review)
Review
The treatment of various types of wounds such as dermal wounds, multidrug resistant bacteria-infected wounds, and chronic diabetic wounds is one of the critical challenges facing healthcare systems. Delayed wound healing can impose a remarkable burden on patients and health care professionals. In this case, given their unique three-dimensional porous structure, biocompatibility, high hydrophilicity, capability to provide a moist environment while absorbing wound exudate, permeability to both gas and oxygen, and tunable mechanical properties, hydrogels with antibacterial function are one of the most promising candidates for wound healing applications. Polylysine is a cationic polymer with the advantages of inherent antibacterial properties, biodegradability, and biocompatibility. Therefore, its utilization to engineer antibacterial hydrogels for accelerating wound healing is of great interest. In this review, we initially discuss polylysine properties, and then focus on the most recent advances in polylysine-containing hydrogels (since 2016) prepared using various chemical and physical crosslinking methods for hemostasis and wound healing applications. Finally, the challenges and future directions in the engineering of these antibacterial hydrogels for wound healing are discussed.
Topics: Hydrogels; Wound Healing; Polylysine; Anti-Bacterial Agents; Humans; Animals; Hemostatics; Hemostasis
PubMed: 38747970
DOI: 10.1039/d3bm01792c -
Soft Matter Sep 2022The α-helix has a significant role in protein function and structure because of its rigidity. In this study, we investigate the persistence length, , of α-helical...
The α-helix has a significant role in protein function and structure because of its rigidity. In this study, we investigate the persistence length, , of α-helical poly-L-lysine, PLL, for two molecular weights. PLL experiences a random coil-helix transition as the pH is raised from 7 to 12. Using light scattering experiments to determine the radius of gyration (), hydrodynamic radius, (), the shape factor (/), and second virial coefficient (), and circular dichroism to determine the helical content, we find the structure and of PLL as a function of pH (7.4-11.4) and ionic strength (100-166 mM). With increasing pH, we find an increase in from 2 nm to 15-21 nm because of α-helix formation. We performed dissipative particle dynamics (DPD) simulations and found a similar increase in . While this is less than that predicted by molecular dynamics simulations, it is consistent with other experimental results, which quantify the mechanics of α-helices. By determining the mechanics of helical polypeptides like PLL, we can further understand their implications to protein function.
Topics: Circular Dichroism; Molecular Weight; Peptides; Polylysine; Protein Conformation, alpha-Helical
PubMed: 36039676
DOI: 10.1039/d2sm00921h -
Protein Science : a Publication of the... Jul 2021Biomolecular condensates assembled through liquid-liquid phase separation (LLPS) of proteins and RNAs are currently recognized to play an important role in cellular...
Biomolecular condensates assembled through liquid-liquid phase separation (LLPS) of proteins and RNAs are currently recognized to play an important role in cellular organization. Their assembly depends on the formation of a network of transient, multivalent interactions between flexible scaffold biomolecules. Understanding how protein and RNA sequences determine these interactions and ultimately regulate the phase separation is an open key challenge. Recent in vitro studies have revealed that arginine and lysine residues, which are enriched in most cellular condensates, have markedly distinct propensities to drive the LLPS of protein/RNA mixtures. Here, we employ explicit-solvent atomistic molecular dynamics simulations to shed light on the microscopic origin of this difference by investigating mixtures of polyU oligonucleotides with either polyR/polyK peptides. In agreement with experiments, our simulations indicate that arginine has a higher affinity for polyU than lysine both in highly diluted conditions and in concentrated solutions with a biomolecular density comparable to cellular condensate. The analysis of intermolecular contacts suggests that this differential behavior is due to the propensity of arginine side chains to simultaneously form a higher number of specific interactions with oligonucleotides, including hydrogen bonds and stacking interactions. Our results provide a molecular description of how the multivalency of the guanidinium group enables the coordination of multiple RNA groups by a single arginine residue, thus ultimately stabilizing protein/RNA condensates.
Topics: Peptides; Poly U; Polylysine; RNA
PubMed: 33982350
DOI: 10.1002/pro.4109 -
International Journal of Biological... Dec 2023With increasing awareness on environmental protection and food safety, the development of biodegradable antimicrobial packaging materials has been paid growing emphasis....
With increasing awareness on environmental protection and food safety, the development of biodegradable antimicrobial packaging materials has been paid growing emphasis. In this work, starch/poly(butylene adipate-co-terephthalate)/ε-polylysine hydrochloride films were prepared by extrusion blowing, and five commercial organically modified nanomontmorillonites (OMMT, including DK1, DK2, DK3, DK4, and DK5) were used as reinforcing agents. Intercalated structures were formed in the nanocomposite films, especially for those with DK3 and DK4 owing to their higher hydrophobicity and larger interlayer spacing. Adding OMMT weakened hydrogen bonds and the gelatinization/plasticization degree of starch. Morphology analysis revealed that the agglomeration of OMMT occurred in the films, but the film containing DK3 still showed a relatively homogeneous microstructure. Loading OMMT enhanced the strength, deformation resistance, thermal stability, surface hydrophobicity, but decreased barrier properties and water sensitivity of the films. Antimicrobial activity showed that the OMMT and ε-polylysine hydrochloride possessed a synergistic effect against Staphylococcus aureus and Escherichia coli. The maximum inhibition rate was observed in that with DK4, approaching 100 %. Findings supported the application of commercial OMMT in manufacturing biodegradable antimicrobial blown films.
Topics: Polyesters; Polylysine; Starch; Anti-Infective Agents; Adipates
PubMed: 37652334
DOI: 10.1016/j.ijbiomac.2023.126609