AFM imaging of bacteria in liquid media immobilized on gelatin coated mica surfaces

Doktycz, Mitchel J.; Sullivan, Claretta J.; Hoyt, Peter R.; Pelletier, Dale A.; Wu, Shijie; Allison, David P.

doi:10.1016/s0304-3991(03)00045-7

Cited by 193 publications

(176 citation statements)

References 20 publications

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“…All samples were prepared by acid treatment to remove organics [21]. Diatom silica samples, suspended in distilled water, were prepared for AFM imaging by placing a 10-μl aliquot of the sample on gelatincoated mica, spreading the sample with a micropipette tip and allowing the sample to air dry [10]. After drying, samples were imaged in contact mode in a PicoPlus AFM (Molecular Imaging, Tempe AZ) under environmental control (12% relative humidity) using silicon nitride cantilevers with manufacturer's suggested spring constant of 0.1 N/m.…”

Section: Previous Afm Examinations Of Diatom Silicamentioning

confidence: 99%

Application of AFM in understanding biomineral formation in diatoms

Hildebrand

Doktycz

Allison

2007

Pflugers Arch - Eur J Physiol

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We review previous work and present new data on the application of atomic force microscopy (AFM) to study biomineral formation in diatoms, unicellular algae that make cell walls of silica. Previous studies examined a small subset of mostly larger diatom species, identifying a prevalence of large particulate silica on the nanoscale. We survey different structures including valves, girdle bands, and elongated spines called setae, in a variety of species, and show a diversity of nano-and meso-scale silica morphologies, even on different portions of the same structure. A general trend of highly organized mesoscale silica structure on the proximal face of cell wall components was observed, with less organized structure occurring on the distal face. The highly organized structures have features suggestive of an underlying linear template, which defines the area of initial silica polymerization. Such features have not been imaged with such clarity previously, demonstrating the advantages of AFM to image small differences in surface morphology and providing new insights and confirming evidence for models of diatom silica structure formation. In addition to its imaging capability, more developed application of AFM to map locations of organic template components on the nanoscale will greatly aid in elucidating mechanisms of diatom biosilica synthesis.

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Section: Previous Afm Examinations Of Diatom Silicamentioning

confidence: 99%

Application of AFM in understanding biomineral formation in diatoms

Hildebrand

Doktycz

Allison

2007

Pflugers Arch - Eur J Physiol

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“…The average mean size of ANPs was observed as 32 nm which is under the agreement of TEM results. Atomic force microscopy is a powerful tool used extensively for observing high-resolution imaging and probe interaction forces [18][19][20] . AFM image exhibited excellent nanosupport for antibacterial potential due to their small size and large surface area (Fig.…”

Section: Resultsmentioning

confidence: 99%

Investigating the antibacterial potential of agarose nanoparticles synthesized by nanoprecipitation technology

Satar

Iizhar

Rasool

et al. 2016

Polish Journal of Chemical Technology

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Herein, an effort was made to investigate the antibacterial potential of agarose nanoparticles (ANPs) and poly(quaternary ammonium) modifi ed ANPs (mANPs) against Escherichia coli (gram-negative bacterium) and Staphylococcus aureus (gram positive bacterium) in liquid systems as well as on agar plates. ANPs were synthesized by nanoprecipitation technology and characterized by XRD, TEM, TGA, DTA and DLS. The particle size estimated was 30 nm while atomic force microscopy was used to observe the interaction of ligand on ANPs. Antimicrobial characterization was monitored by colony forming units (CFU) as a function of ANPs concentration on agar plates. It was observed that ANPs showed 15 x 10 9 /ml CFU after 24 hours of incubation at 20 mM ANPs concentration while the modifi ed ANPs exhibited 21 x 10 9 /ml CFU under similar incubation conditions. Moreover, zone of inhibition (ZOI) was 2.9 and 3.8 cm, respectively for E. coli by ANPs at 0.2 and 0.4 mM, respectively while it was 3.2 and 3.8 cm respectively by modifi ed ANPs under similar conditions. Similarly, ZOI for S. aureus by ANPs at 0.2 and 0.4 mM was observed at 3.1 and 4.0 cm, respectively, while these values were 3.5 and 4.1 cm, respectively for modifi ed ANPs under similar incubation conditions.

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“…Immobilization of bacteria on poly-l-lysine treated mica is demonstrated to be a reliable method for AFM both in air and liquid [16,17]. We followed the protocol of preparing substrate proposed by Bolshakova et al with slight modifications [16].…”

Section: Poly-l-lysine Mica Preparation and Bacteria Immobilizationmentioning

confidence: 99%

Inhibition ofEscherichia colirespiratory enzymes by short visible femtosecond laser irradiation

Lin

Hsu

et al. 2014

J. Phys. D: Appl. Phys.

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Abstract:Visible femtosecond laser is shown to be capable of selectively inactivating a wide spectrum of microorganisms in a wavelength and pulse width dependent manner.However, the mechanism of how visible femtosecond laser affects the viability of different microorganisms is still elusive. In this report, the cellular surface properties, membrane integrity and metabolic rate of Escherichia coli (E.coli) irradiated by a visible femtosecond laser (λ=415nm, pulse width=100fs) with different exposure time were investigated. Our results showed that femtosecond laser treatment for 60 minutes (min) led to cytoplasmic leakage, protein aggregation and alternation of the physical properties of E. coli cell membrane. In comparison, a 10 min exposure of bacteriatofemtosecond laser irradiation induced an immediate reduction of 75% of the glucose-dependent respiratory rate, while the cytoplasmic leakage was not detected.Results from enzymatic assays showed that oxidases and dehydrogenases involving in E.coli respiratory chain exhibited divergent susceptibility after laser irradiation. This early commencement of respiratory inhibition after a short irradiation is presumed to play a dominant effect on the early stage of bacteria inactivation.

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AFM imaging of bacteria in liquid media immobilized on gelatin coated mica surfaces

Cited by 193 publications

References 20 publications

Application of AFM in understanding biomineral formation in diatoms

Application of AFM in understanding biomineral formation in diatoms

Investigating the antibacterial potential of agarose nanoparticles synthesized by nanoprecipitation technology

Inhibition ofEscherichia colirespiratory enzymes by short visible femtosecond laser irradiation

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