Early stages of antibacterial damage of metallic nanoparticles by TEM and STEM-HAADFOctober 12, 2017
The virulence of pathogens is considered an important health care problem due to their resistance against conventional antibiotics. The recent challenge for researchers involves the design of functional alternatives such as nanomaterials, used as antibacterial agents. Recently, metallic nanoparticles (NPs) have demonstrated high bacteriostatic and bactericidal properties associated with the increase of surface area to volume ratio, enhancing their physical and chemical activity, and they are considered as the new generation of antimicrobial agents. Several studies have been focused on the antimicrobial properties of metallic NPs and their action mechanism in contact with microorganisms, but is still not well understood. Different bacterial damage processes have been reported, and they are associated with alterations to different cellular components, such as cell wall, proteins and DNA. All of them induce changes in cell function to finally promote cell death. Recent advances in electron microscopy offer new analytical techniques based on the image contrast and their correlation with the atomic mass, allowing to determine morphology and composition. The progress of combined STEM-HAADF technique is related with the imaging of biological samples morphology and its elemental analysis at nanometric scale. A major feature of combined techniques is the analyses of bacterial damage produced by the interaction with NPs, aiming to elucidate the early stages of the process.
The present study is focused on the antibacterial damage produced by the interaction of Silver (Ag) and Copper (Cu) based NPs with Gram-negative Pseudomonas aeruginosa by means of TEM and combined STEM-HAADF. In this regard, NP structure and their antibacterial activity (AA) were determined. The adhesion and penetration of NPs were determined by TEM and STEM-HAADF, aiming to contribute to the elucidation of the primary antibacterial mechanism of metallic NPs.
Ag and Cu NPs have emerged as relevant materials for the synthesis of biomedical devices due to their antibacterial properties. Here we go into a detailed observation of the early stages of AA produced by Ag and Cu NPs using commercial sources. In this regard, both NPs display AA depending on NP concentration. TEM images show NPs adhesion on bacterial cells, suggesting that the interaction between bacteria and NPs induce changes in bacterial structure as the overall shape becomes irregular and the cell wall is distorted after direct contact. Metallic NPs and other ionic species that they might release from their surface when in solution could interact with the anionic lipopolysaccharides of the Gram-negative cell wall, as it has been reported before. These interactions then lead to the disequilibrium on the cell causing permeation and finally result in cell death. The STEM-HAADF technique also proves the NP adhesion and penetration by intracellular localization, detecting Ag/Cu species analyzed by elemental mapping. Moreover, the relative amount of phosphorus (P) and sulfur (S) increases slightly in P. aeruginosa with the presence of NPs. These elements are associated with damaged proteins of the outer cell membrane.
This study shows the early stages of antibacterial damage caused by metallic NPs on Gram-negative Pseudomonas aeruginosa by means of HRTEM and combined STEM-HAADF. Combined analyses by TEM and STEM-HAADF can be a powerful tool to understand the primary antibacterial mechanism of metallic NPs and the bacterial response to damage, which are key processes for the rational design of antimicrobial nanomaterials.
aDepartamento de Materiales Avanzados, Centro de Investigación en Química Aplicada (CIQA), Blvd. Enrique Reyna Hermosillo No. 140, Saltillo, Coahuila 25294, México.
bCentro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV) Unidad Querétaro. Libramiento Norponiente No. 2000, Fracc. Real de Juriquilla. Querétaro, Querétaro, 76230, México.
cDepartamento de Biología, División de Ciencias Naturales y Exactas, Universidad de Guanajuato. Noria Alta s/n, Guanajuato, Guanajuato 36050, México.
Bentham Science Publishers
Related Cell Death Articles:
Researchers from IDIBELL -- within the Marie Curie ITN TRAIN-ERs -- have characterized the cell death process due to starvation, in which the endoplasmic reticulum plays a leading role.
Billions of cells in our bodies die every day in an important process called apoptosis.
A Children's National Health System research team has uncovered a novel process by which the gene APOL1 contributes to renal disease, according to a paper published Nov.
Researchers from Ludwig-Maximilians-Universitaet (LMU) in Munich have demonstrated how deregulation of an epigenetic mechanism that is active only in the early phases of neurogenesis triggers the subsequent death of neural cells.
For some pathogens, attack is the best form of defense -- they enter immune cells of the human body.
Researchers have identified a new biological pathway involved in Alzheimer's disease.
In the May 2016 Nature Communications, investigators at the Medical University of South Carolina report that CHOP/GADD153-dependent apoptosis is mediated by the micro-RNA miR-216b.
Killed cancer cells serve as a potent anti-cancer vaccine Researchers in the group of Prof.
New research from The Wistar Institute shows how one protein found on the endoplasmic reticulum can serve as a target for stimulating the immune system and a more direct target for cellular death in B cell malignancies.
Researchers at St. Jude Children's Research Hospital have uncovered a new pathway for mitochondrial cell death that involves the protein BCL-2 ovarian killer otherwise known as BOK.
Related Cell Death Reading:
Cell 2455, Death Row: A Condemned Man's Own Story
by Caryl Chessman (Author), Joseph Longstreth (Introduction)
In June 1948, 27-year-old petty criminal Caryl Chessman was sentenced in California on two counts of sexual assault, receiving two death sentences as punishment in a case that remains one of the most baffling episodes in American legal history. Maintaining his innocence of these crimes, Chessman lived in Cell 2455, a four-by-ten foot space on Death Row in San Quentin for the twelve years between his sentencing and eventual execution. He spent this time, punctuated by eight separate stays of execution, writing this memoir — a moving and pitiless account of his life in crime and the early... View Details
Cell 2455, Death Row: Caryl Chessman's Own Story
by Caryl Chessman (Author)
Caryl Whittier Chessman (May 27, 1921 - May 2, 1960) was a convicted robber and rapist who gained fame as a death row inmate in California. Chessman's case attracted worldwide attention, and as a result he became a cause célèbre for the movement to ban capital punishment. View Details
Cell Death: Apoptosis and Other Means to an End
by Douglas R. Green (Author)
One million cells in our bodies die every second--they commit suicide by a mechanism known as apoptosis. Apoptosis is essential for survival of the body as a whole and has critical roles in various developmental processes and the immune system.
In Cell Death, Douglas Green provides a clear and comprehensive view of apoptosis and other cell death mechanisms. Taking a bottom-up approach, he starts with the enzymes that perform the execution process (a family of proteases termed caspases) and examines their cellular targets and the ways in which they are activated. He then looks... View Details
Means to an End: Apoptosis and Other Cell Death Mechanisms
by Douglas R Green (Editor)
One million cells in our bodies die every secondthey commit suicide by a mechanism known as apoptosis. Apoptosis is essential for survival of the body as a whole and has critical roles in various developmental processes and the immune system. In Means To An End, Douglas Green provides a clear and comprehensive view of apoptosis and other cell death mechanisms. Taking a bottom-up approach, he starts with the enzymes that perform the execution process (a family of proteases termed caspases) and examines their cellular targets and the ways in which they are activated. He then looks at the... View Details
Dead Man's Cell Phone (TCG Edition)
by Sarah Ruhl (Author)
“Satire is her oxygen. . . . In her new oddball comedy, Dead Man’s Cell Phone, Sarah Ruhl is forever vital in her lyrical and biting takes on how we behave.”—The Washington Post
“Ruhl’s zany probe of the razor-thin line between life and death delivers a fresh and humorous look at the times we live in.”—Variety
“Sarah Ruhl is deliriously imaginative and fearless in her choice of subject matter. She is an original.”—Molly Smith, artistic director, Arena Stage
An incessantly ringing cell phone in a quiet café. A stranger at the... View Details
Apoptosis: The Life and Death of Cells (Developmental & Cell Biology)
by Christopher Potten (Author), James Wilson (Author)
This book describes the biological implications and significance of apoptosis. Occurring naturally throughout the lifetime of most multicellular organisms, apoptosis, or programmed cell death, accounts for the continuous turnover of cells in the body. However, the genes regulating apoptosis are defective in many cancers. View Details
The Prisoner in the Third Cell
by Gene Edwards (Author)
Imprisoned by Herod, John the Baptist struggles to understand a Lord who did not meet his expectations―a dramatic account offering insight into the ways of God. View Details
by Ron Goulart (Author)
1st Beagle Boxer edition paperback. 1971. good to vg condition. 95111-A. In stock shipped from our UK warehouse View Details
Cell Death Techniques: A Laboratory Manual
by Ricky Johnstone (Editor), John Silke (Editor)
Regulated cell death, which is involved in nearly every aspect of animal development and physiology, can be challenging to study in the laboratory. There are multiple types of cell death, several interconnected signaling pathways can be activated, and the postmortem consequences may vary. Therefore, a combination of specialized techniques is often required to characterize and confirm cell death in the system of interest.
This laboratory manual provides a comprehensive suite of step-by-step protocols for inducing, detecting, visualizing, characterizing, and quantifying cell death in a... View Details
Death: Corpses, Cadavers, and Other Grave Matters (Discovery!)
by Elizabeth A. Murray (Author)
Everyone dies . . . but what happens inside the human body when death occurs? What body systems are key for holding on to life? And what value does studying death have for those of us still living? Explore all of the answers with a forensic scientist who takes a look at the body's interconnected cellular systems and the links between life and death.View Details