Synthesis and antimicrobial photodynamic effect of methylene blue conjugated carbon nanotubes on E. coli and S. aureus

Parasuraman, Paramanantham; Anju, V. T.; Lal, Sham; Sharan, Alok; Siddhardha, Busi; Kaviyarasu, K.; Arshad, Muhammad; Dawoud, Turki M.; Syed, Asad

doi:10.1039/c8pp00369f

Cited by 86 publications

(29 citation statements)

References 42 publications

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“…Previously, CNTs were used for conjugating methylene blue dye, which exhibited enhanced phototoxicity against E. coli and S. aureus . The ability of CNTs to act as a dye delivery vehicle to bacterial systems for enhanced antibacterial was confirmed 23. In the present study, both bacterial strains were more sensitive to the MGCNT-mediated killing than that of free dye and CNTs, validating the ability of CNTs to carry MG and exhibit pronounced phototoxicity against test bacteria.…”

Section: Discussionsupporting

confidence: 74%

“…The radiant exposure was measured as 58.49 J cm −2 . The bacteria were treated with MG (50 µg/mL)23 and MGCNTs (484.82 µg/mL) such that the final concentration of MG present in the conjugate was equal to 50 µg/mL. The optimization of exposure time for maximum photoinactivation in test bacteria was carried out using different irradiation times.…”

Section: Methodsmentioning

confidence: 99%

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Malachite green-conjugated multi-walled carbon nanotubes potentiate antimicrobial photodynamic inactivation of planktonic cells and biofilms of Pseudomonas aeruginosa and Staphylococcus aureus

Anju¹,

Parasuraman²,

Siddhardha³

et al. 2019

IJN

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Purpose: Infections associated with medical devices that are caused by biofilms remain a considerable challenge for health care systems owing to their multidrug resistance patterns. Biofilms of Pseudomonas aeruginosa and Staphylococcus aureus can result in life-threatening situations which are tough to eliminate by traditional methods. Antimicrobial photodynamic inactivation (aPDT) constitutes an alternative method of killing deadly pathogens and their biofilms using reactive oxygen species (ROS). This study investigated the efficacy of enhanced in vitro aPDT of P. aeruginosa and S. aureus using malachite green conjugated to carboxyl-functionalized multi-walled carbon nanotubes (MGCNT). Both the planktonic cells and biofilms of test bacteria were demonstrated to be susceptible to the MGCNT conjugate. These MGCNT conjugates may thus be employed as a facile strategy for designing antibacterial and anti-biofilm coatings to prevent the infections associated with medical devices. Methods: Conjugation of the cationic dye malachite green to carbon nanotube was studied by UV-visible spectroscopy, high-resolution transmission electron microscopy, and Fourier transform infrared spectrometry. P. aeruginosa and S. aureus photodestruction were studied using MGCNT conjugate irradiated for 3 mins with a red laser of wavelength 660 nm and radiant exposure of 58.49 J cm −2 . Results: Upon MGCNT treatment, S. aureus and P. aeruginosa were reduced by 5.16 and 5.55 log 10 , respectively. Compared to free dye, treatment with MGCNT afforded improved phototoxicity against test bacteria, concomitant with greater ROS production. The results revealed improved biofilm inhibition, exopolysaccharide inhibition, and reduced cell viability in test bacteria treated with MGCNT conjugate. P. aeruginosa and S. aureus biofilms were considerably reduced to 60.20±2.48% and 67.59±3.53%, respectively. Enhanced relative MGCNT phototoxicity in test bacteria was confirmed using confocal laser scanning microscopy. Conclusion: The findings indicated that MGCNT conjugate could be useful to eliminate the biofilms formed on medical devices by S. aureus and P. aeruginosa.

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Section: Discussionsupporting

confidence: 74%

Section: Methodsmentioning

confidence: 99%

Malachite green-conjugated multi-walled carbon nanotubes potentiate antimicrobial photodynamic inactivation of planktonic cells and biofilms of Pseudomonas aeruginosa and Staphylococcus aureus

Anju¹,

Parasuraman²,

Siddhardha³

et al. 2019

IJN

Self Cite

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“…In one approach, Sah et al used carboxylic acid-modified SWCNTs as a platform for attachment of amino functionalised tetraphenylporphyrin (TPP) photosensitizers [162] and used this system against S. aureus. Non-covalent encapsulation of TBO and MB dyes in MWCNTs was reported by Busi and coworkers [163,164]. Carbon nanographene oxide is another typical carbon material that has been applied in this strategy, and was used as a vehicle for NIR absorbing ICG [165].…”

Section: Hybrid and Inorganic Nanoparticlesmentioning

confidence: 97%

Design of Photosensitizing Agents for Targeted Antimicrobial Photodynamic Therapy

2020

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Photodynamic inactivation of microorganisms has gained substantial attention due to its unique mode of action, in which pathogens are unable to generate resistance, and due to the fact that it can be applied in a minimally invasive manner. In photodynamic therapy (PDT), a non-toxic photosensitizer (PS) is activated by a specific wavelength of light and generates highly cytotoxic reactive oxygen species (ROS) such as superoxide (O2−, type-I mechanism) or singlet oxygen (1O2*, type-II mechanism). Although it offers many advantages over conventional treatment methods, ROS-mediated microbial killing is often faced with the issues of accessibility, poor selectivity and off-target damage. Thus, several strategies have been employed to develop target-specific antimicrobial PDT (aPDT). This includes conjugation of known PS building-blocks to either non-specific cationic moieties or target-specific antibiotics and antimicrobial peptides, or combining them with targeting nanomaterials. In this review, we summarise these general strategies and related challenges, and highlight recent developments in targeted aPDT.

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“…Incubation with more concentrated solutions (200 μg mL −1 , i.e., 62.5 nmoles MB per 100 μL) resulted in increased MB uptake values, although a different trend was observed within the three groups, whereby L929 cells revealed the lowest value of MB content (9 nmoles, ~14 mol.%), followed by E. coli (10.8 nmoles, ~17 mol.%) and S. mutans (17 nmoles, ~27 mol.%). Similar levels of MB uptake were observed in HeLa epithelial cells [ 40 ], whilst higher values were recorded when E. coli were exposed to solutions with increased (~50-fold) MB concentration [ 41 ]. Compared to MB, cells incubated with ER-supplemented solutions generally displayed lower PS uptake, with the highest value (2.7 nmoles, ~12 mol.%) recorded in L929 cells treated with the more concentrated (200 μg mL −1 , i.e., 22.7 nmoles in 100 μL) ER solution ( Figure 1 B).…”

Section: Resultsmentioning

confidence: 58%

Hydrolytic Degradability, Cell Tolerance and On-Demand Antibacterial Effect of Electrospun Photodynamically Active Fibres

et al. 2020

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Photodynamically active fibres (PAFs) are a novel class of stimulus-sensitive systems capable of triggering antibiotic-free antibacterial effect on-demand when exposed to light. Despite their relevance in infection control, however, the broad clinical applicability of PAFs has not yet been fully realised due to the limited control in fibrous microstructure, cell tolerance and antibacterial activity in the physiologic environment. We addressed this challenge by creating semicrystalline electrospun fibres with varying content of poly[(l-lactide)-co-(glycolide)] (PLGA), poly(ε-caprolactone) (PCL) and methylene blue (MB), whereby the effect of polymer morphology, fibre composition and photosensitiser (PS) uptake on wet state fibre behaviour and functions was studied. The presence of crystalline domains and PS–polymer secondary interactions proved key to accomplishing long-lasting fibrous microstructure, controlled mass loss and controlled MB release profiles (37 °C, pH 7.4, 8 weeks). PAFs with equivalent PLGA:PCL weight ratio successfully promoted attachment and proliferation of L929 cells over a 7-day culture with and without light activation, while triggering up to 2.5 and 4 log reduction in E. coli and S. mutans viability, respectively. These results support the therapeutic applicability of PAFs for frequently encountered bacterial infections, opening up new opportunities in photodynamic fibrous systems with integrated wound healing and infection control capabilities.

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Synthesis and antimicrobial photodynamic effect of methylene blue conjugated carbon nanotubes on E. coli and S. aureus

Abstract: The methylene blue and CNT nanoconjugate effectively produced singlet oxygen via photoactivation using a diode laser. It was employed for aPDT against pathogenic bacteria.

Cited by 86 publications

References 42 publications

<p>Malachite green-conjugated multi-walled carbon nanotubes potentiate antimicrobial photodynamic inactivation of planktonic cells and biofilms of <em>Pseudomonas aeruginosa</em> and <em>Staphylococcus aureus</em></p>

<p>Malachite green-conjugated multi-walled carbon nanotubes potentiate antimicrobial photodynamic inactivation of planktonic cells and biofilms of <em>Pseudomonas aeruginosa</em> and <em>Staphylococcus aureus</em></p>

Design of Photosensitizing Agents for Targeted Antimicrobial Photodynamic Therapy

Hydrolytic Degradability, Cell Tolerance and On-Demand Antibacterial Effect of Electrospun Photodynamically Active Fibres

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