Scalable Synthesis of Self‐Disinfecting Polycationic Coatings for Hospital Relevant Surfaces
Advanced Materials Interfaces, Feb 12, 2023
The prevention of microbial infections is a global challenge. Efficient antimicrobial coatings th... more The prevention of microbial infections is a global challenge. Efficient antimicrobial coatings that rapidly kill microorganisms upon contact can help minimize their transmission. However, their scalable synthesis is challenging. This work demonstrates the scalable synthesis and characterization of self‐disinfecting nanofilms for the postmodification of hospital‐relevant surfaces. Their antimicrobial action is based on charge interactions between a supercharged cationic surface film and the negatively charged bacteria membrane. Photoinitiated bulk polymerization of an air‐dried [2‐(methacryloyloxy)ethyl]trimethylammonium chloride film on cotton (gowns), nitrile rubber (protective gloves), and glass surfaces (tables, screens) is used for their supercharging, and studied with streaming potential measurements. A 6 nm thick coating dominated by cationic quarternary amine groups is shown by a combination of spectroscopic imaging ellipsometry and X‐ray photoelectron spectroscopy. Antimicrobial in vitro evaluation of the coated surfaces demonstrates up to ≈4 log reductions in bacterial populations in less than 5 min. Confocal laser scanning microscopy and live‐dead staining confirm the surface‐induced killing of bacteria. The coating's range of compatible materials and its rapid bactericidal activity can combat the surface transmission of bacteria and may help to contain the spread of infectious diseases. Its synthesis in environmental conditions is promising for integration into industrial processes.
Formation of highly ordered liquid crystalline coatings – an <i>in situ</i> GISAXS study
Physical Chemistry Chemical Physics, 2018
In situ GISAXS and AFM reveal the formation of highly geometrically organized glycerol monooleate... more In situ GISAXS and AFM reveal the formation of highly geometrically organized glycerol monooleate based liquid crystalline films on silicon wafers.
Surface-associated microbial infections and contaminations are a major challenge in various field... more Surface-associated microbial infections and contaminations are a major challenge in various fields including food and health sectors. This study demonstrates the design of antimicrobial coatings based on the self-assembly of the food-grade amphiphilic lipid, glycerol monooleate, with the human cathelicidin-derived antimicrobial peptide LL-37. Structural properties of the coating and alterations with composition were studied with contemporary experimental methods including grazing-incidence small-angle X-ray scattering (GISAXS) and imaging ellipsometry. The integration of the LL-37 and its release from the thin nanostructured films was studied with confocal Raman microscopy. Additional biological evaluation studies with clinically relevant bacterial strains, namely Pseudomonas aeruginosa (Gram negative) and Staphylococcus aureus (Gram positive), were used to investigate the antimicrobial activity of the coatings. Significant killing activity of the coating was found against both bacterial strains. The presented findings contribute to the fundamental understanding of lipid-peptide selfassembly on the surface and may open up a promising strategy for designing simple, sustainable antimicrobial coatings for medical and food applications.
Over the past decade, the rapid increase in the incidence of antibiotic-resistant bacteria has pr... more Over the past decade, the rapid increase in the incidence of antibiotic-resistant bacteria has promoted research towards alternative therapeutics such as antimicrobial peptides (AMPs), but their biodegradability limits their application. Encapsulation into nanocarriers based on the self-assembly of surfactant-like lipids is emerging as a promising strategy for the improvement of AMPs' stability and their protection against degradation when in biological media. An in-depth understanding of the interactions between the structure-forming lipids and AMPs is required for the design of nanocarriers. This in silico study, demonstrates the self-assembly of the amphiphilic lipid glycerol monooleate (GMO) with the antimicrobial peptide LL-37 into nanocarriers on the molecular scale. Molecular dynamics (MD) simulations show the formation of direct micelles, with either one or two interacting LL-37, and vesicles in this two-component system in agreement with experimental results from small-angle X-ray scattering studies. The hydrophobic contacts between LL-37 and GMOs in water appear responsible for the formation of these nanoparticles. The results also suggest that the enhanced antimicrobial efficiency of LL-37 in these nanocarriers that was previously observed experimentally can be explained by the availability of its side chains with charged amino acids, an increase of the electrostatic interaction and a decrease of the peptide's conformational entropy upon interacting with GMO. The results of this study contribute to the fundamental understanding of lipid-AMP interactions and may guide the comprehensive design of lipid-based self-assembled nanocarriers for antimicrobial peptides.
In article number 1900080, Suresh K. Bhargava, Vipul Bansal, and co-workers present a non-convent... more In article number 1900080, Suresh K. Bhargava, Vipul Bansal, and co-workers present a non-conventional colloidal lithography approach to prepare patterned surfaces of inorganic/organic hybrid heterostructures of ZnO/Ag/AgTCNQ. The work shows that the control over the size and coverage of heterojunctions achieved through colloidal lithography has significant influence over their photocatalytic activity.
Evaluation of fiber and debris release from protective COVID-19 mask textiles and in vitro acute cytotoxicity effects
Environment International, Sep 1, 2022
Scalable Synthesis of Self‐Disinfecting Polycationic Coatings for Hospital Relevant Surfaces
Advanced Materials Interfaces
The prevention of microbial infections is a global challenge. Efficient antimicrobial coatings th... more The prevention of microbial infections is a global challenge. Efficient antimicrobial coatings that rapidly kill microorganisms upon contact can help minimize their transmission. However, their scalable synthesis is challenging. This work demonstrates the scalable synthesis and characterization of self‐disinfecting nanofilms for the postmodification of hospital‐relevant surfaces. Their antimicrobial action is based on charge interactions between a supercharged cationic surface film and the negatively charged bacteria membrane. Photoinitiated bulk polymerization of an air‐dried [2‐(methacryloyloxy)ethyl]trimethylammonium chloride film on cotton (gowns), nitrile rubber (protective gloves), and glass surfaces (tables, screens) is used for their supercharging, and studied with streaming potential measurements. A 6 nm thick coating dominated by cationic quarternary amine groups is shown by a combination of spectroscopic imaging ellipsometry and X‐ray photoelectron spectroscopy. Antimicro...
Evaluation of fiber and debris release from protective COVID-19 mask textiles and in vitro acute cytotoxicity effects
Surface-associated microbial infections and contaminations are a major challenge in various field... more Surface-associated microbial infections and contaminations are a major challenge in various fields including food and health sectors. This study demonstrates the design of antimicrobial coatings based on the self-assembly of the food-grade amphiphilic lipid, glycerol monooleate, with the human cathelicidin-derived antimicrobial peptide LL-37. Structural properties of the coating and alterations with composition were studied with contemporary experimental methods including grazing-incidence small-angle X-ray scattering (GISAXS) and imaging ellipsometry. The integration of the LL-37 and its release from the thin nanostructured films was studied with confocal Raman microscopy. Additional biological evaluation studies with clinically relevant bacterial strains, namely Pseudomonas aeruginosa (Gram negative) and Staphylococcus aureus (Gram positive), were used to investigate the antimicrobial activity of the coatings. Significant killing activity of the coating was found against both bacterial strains. The presented findings contribute to the fundamental understanding of lipid-peptide selfassembly on the surface and may open up a promising strategy for designing simple, sustainable antimicrobial coatings for medical and food applications.
Colloidal structures are crucial components in biological systems and provide a vivid and seeming... more Colloidal structures are crucial components in biological systems and provide a vivid and seemingly infinite source of inspiration for the design of functional bio-inspired materials. They form multi-dimensional confinements and shape living matter, and transport and protect bioactive molecules in harsh biological environments such as the stomach. Recently, colloidal nanostructures based on natural antimicrobial peptides have emerged as promising alternatives to conventional antibiotics. This contribution summarizes the recent progress in the understanding and design of these bio-inspired antimicrobial nanomaterials, and discusses their advances in the form of dispersions and as surface coatings. Their potential for applications in future food and healthcare materials is also highlighted. Further, it discusses challenges in the characterization of structure and dynamics in these materials.
Molecular dynamics simulations of glycerol-monooleate (GMO)/LL-37 nanocarriers show that hydropho... more Molecular dynamics simulations of glycerol-monooleate (GMO)/LL-37 nanocarriers show that hydrophobic interactions among the molecules drive the formation of GMO/LL-37 micelles.
In article number 1900080, Suresh K. Bhargava, Vipul Bansal, and co-workers present a non-convent... more In article number 1900080, Suresh K. Bhargava, Vipul Bansal, and co-workers present a non-conventional colloidal lithography approach to prepare patterned surfaces of inorganic/organic hybrid heterostructures of ZnO/Ag/AgTCNQ. The work shows that the control over the size and coverage of heterojunctions achieved through colloidal lithography has significant influence over their photocatalytic activity.
The rational design of alternative antimicrobial materials with reduced toxicity toward mammalian... more The rational design of alternative antimicrobial materials with reduced toxicity toward mammalian cells is highly desired due to the growing occurrence of bacteria resistant to conventional antibiotics. A promising approach is the design of lipid‐based antimicrobial nanocarriers. However, most of the commonly used polymer‐stabilized nanocarriers are cytotoxic. Herein, the design of a novel, stabilizer‐free nanocarrier for the human cathelicidin derived antimicrobial peptide LL‐37 that is cytocompatible and promotes cell proliferation for improved wound healing is reported. The nanocarrier is formed through the spontaneous integration of LL‐37 into novel, stabilizer‐free glycerol mono‐oleate (GMO)‐based cubosomes. Transformations in the internal structure of the cubosomes from Pn3m to Im3m‐type and eventually their transition into small vesicles and spherical micelles are demonstrated upon the encapsulation of LL‐37 into their internal bicontinuous cubic structure using small angle X...
Colloidal lithography (CL) has evolved as an alternative to conventional photo‐ and electron‐beam... more Colloidal lithography (CL) has evolved as an alternative to conventional photo‐ and electron‐beam lithography to pattern surfaces with nanometer range resolution. As CL offers substrate‐independent precise positioning and patterning of nanomaterials as long‐range ordered crystals, this has seen new opportunities in optoelectronics. Herein, the scope of CL is expanded to fabricate for the first time, 3D organic–inorganic heterojunction photocatalysts with well‐controlled spacing and coverage density. To achieve this, monodisperse polystyrene (PS) beads of different sizes are used as colloidal masks on a ZnO substrate. Electron beam assisted silver deposition onto these PS masks, and subsequent removal of PS lead to the formation of patterns of silver nanostars on the ZnO thin film. The solid–vapor reaction of silver nanostars with a metal‐coordinating charge‐transfer complex of 7,7,8,8‐tetracyanoquinodimethane (TCNQ) allows spontaneous conversion of Ag nanostars to the large aspect r...
Formation of highly ordered liquid crystalline coatings – an in situ GISAXS study
Physical Chemistry Chemical Physics, 2018
In situ GISAXS and AFM reveal the formation of highly geometrically organized glycerol monooleate... more In situ GISAXS and AFM reveal the formation of highly geometrically organized glycerol monooleate based liquid crystalline films on silicon wafers.
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