A team of researchers at the Swiss Federal Institute of Technology has developed a high-performance Scanning Ion Conductance Microscope (SICM) using the latest advances in nanopositioning, nanopore fabrication, microelectronics and controls engineering.
Time-resolved scanning allows the 3D visualization of dynamic structures in a eukaryotic cell membrane at nanometer resolutions.
Studying the functions of living cells and organelles at the nanoscale is vital to understanding the causes of disease. Traditional approaches, including electron microscopy, may, unfortunately, damage these cells.
The Swiss researchers developed a SCIM microscope that resolves spatiotemporally diverse three-dimensional processes on a eukaryotic cell membrane at sub-5 nanometer axial resolution. This may offer insights into intracell interactions in the fight against infections and disease.
The Origins of Scanning Probe Microscopy
Studying the intricate functions of living cells at the nanoscale is a unique challenge. Researchers have developed a range of techniques to meet this challenge, including atomic force microscopy (AFM), scanning tunneling microscopy (STM) and Scanning Probe Electrochemistry (SPE).
Scanning probe microscopy (SPM) forms images of surfaces using a probe that scans the specimen. The technique made its first appearance in 1981 in the form of the scanning tunneling microscope, which produces images at atomic resolution by scanning a specimen using a probe.
In scanning probe microscopes, piezoelectric actuators move the probe with atomic-level precision controlled by electronics. The probe raster scans the specimen. It captures discrete data points which are used to form an image. Its manner of scanning is called a mode.
Scanning Ion Conductance Microscopy (SICM) was developed by P.K. Hansma and his colleagues at the University of California in 1989. An electrolyte-containing aqueous medium is a poor conductor.
A SCIM microscope scans a nanoprobe (micro-pipette with a 50 to 100 nm hole) close to the surface of the specimen. As the probe moves across the specimen, ionic currents flow through the pipette. The strengths of these currents vary according to the electrical resistance across the sample’s surface, thus revealing information about its composition.
In the hopping mode described by the Swiss team, however, the nanoprobe is not raster scanned. It moves vertically up and down in a hopping motion.
The probe approaches the specimen at a distance of 25 to 50 nm at specified points and retracts, thus providing discrete points of measurement from which an image is formed. Crucially, the probe never touches the specimen, thus preventing damage to the sample.
SCIM microscopy is, therefore, a powerful tool for capturing the steep changes in a cell’s topography without affecting the sample.
Time-Resolved Scanning Ion Conductance Microscopy
Time-resolved SICM microscopes produce high-resolution profiles of cell shapes and surface characteristics. However, these need to be correlated with biochemical information and changes to the internal organization of the cells.
The Swiss team integrated an inverted optical microscope to a SICM microscope which allowed them to combine recently developed super-resolution microscopy techniques into their approach.
The SICM setup consisted of a custom-built pipette Z-actuator (vertical actuator) integrated into a controlled-atmosphere device, critical for cell viability during imaging.
The imaging of eukaryotic cells requires piezo actuators with a long-range (>10−20 μm). This leads to a trade-off between resonance frequency and the range of the actuator. The team overcame this by adaptively slowing down the pipette’s velocity and applying a gain to the piezo motion as a function of the current interaction curve.
The Z-actuator achieved a wide mechanical displacement amplification of 22 μm scanning range on the cell surface. It was driven by a custom-made piezo controller and integrated with a stepper-motor stage for approaching the sample.
The team used borosilicate and quartz nanopipettes for probing. They were fabricated with a CO2 laser puller with a radius of 20 to 60 nm in size. Quartz capillaries were shrunk to a sub-10-nm radius using electron beam irradiation.
Many cellular processes occur at time scales of minutes or hours and are easily trackable with time-lapse SICM. Subcellular processes, such as endocytosis or infection, however, occur much faster. The Swiss team’s technique combines the capability to address large imaging volumes (up to 220 000 μm3) relatively quickly with high-speed SICM imaging of small details on live cells.
The wide range of measurements possible (Scan sizes from 500 × 500 nm2 to 100 × 100 μm2, imaging speeds from 0.5 s/image to 20 min/image; Number of pixels per image from 1 Kp to 1 Mp; Depth of view of 22 μm with axial resolution below 10 nm) significantly enhances the range of biological studies facilitated by SICM microscopy.
News
GHCE Concept
From the preface of the book Global Health Care Equivalency in the Age of Nanotechnology, Nanomedicine and Artificial Intelligence, Edited by Frank Boehm: Since the publication of my first book (Nanomedical Device and Systems [...]
Human Bodies Are Producing Two Billion Tons of CO2 a Year
A new study reveals that the amount of carbon dioxide produced by human metabolism has increased dramatically over three decades. The carbon dioxide produced by human bodies as they convert food into energy increased [...]
A Hidden DNA Mechanism Could Explain How 20% of Human Cancers Develop
Researchers have identified an unexpected molecular vulnerability in cancers carrying BAF mutations. Mutations found in roughly 20% of human cancers may promote tumor growth by changing how DNA is organized inside cells. Researchers have [...]
Ebola kills over 5,300 in fastest-growing outbreak on record
Africa’s latest Ebola outbreak has killed nearly 5,400 people, the vast majority of them in the Democratic Republic of Congo (DRC), according to the continent’s top health agency. Africa Centres for Disease Control and [...]
China makes early progress in using sound waves to stimulate damaged brains
Chinese researchers are testing whether focused ultrasound can help restore consciousness in patients with severe brain injuries, adding to a growing international effort to use sound waves to stimulate deep brain structures without surgery. [...]
Micro-drones fly through the body thanks to ultrasound
At the EPFL, micro-drones have been developed that can be moved without a motor or battery.No motors, no batteries, no electronics on board, just small cavities that convert sound waves into thrust: this is [...]
A Single Enzyme Could Hold the Key to Treating a Devastating Brain Disorder
Blocking an enzyme’s production restored brain growth and healthy behaviors in mice engineered to develop Angelman syndrome, pointing to a possible treatment target. Children with Angelman syndrome begin to show difficulties with thinking and [...]
Scientists Develop a Clever New Way To Kill Cancer Cells From the Inside
Scientists have developed an experimental strategy that exploits a chemical byproduct of cancer cells to produce anticancer drugs directly inside them. Scientists in Japan have developed an experimental method that uses a chemical produced [...]
Our books are available worldwide!
Online Sellers other than Amazon, Routledge, and IOPP Indigo Global Health Care Equivalency in the Age of Nanotechnology, Nanomedicine and Artifcial Intelligence Global Health Care Equivalency In The Age Of Nanotechnology, Nanomedicine And Artificial [...]
After only a short training, people in a coma managed to send targeted signals
Researchers have succeeded in communicating with brain-injured patients who are unconscious. They see enormous potential in this for future treatments. Patients who lie motionless in bed after a severe brain injury and do not [...]
MIT Scientists Reprogram Immune Cells Inside the Body To Destroy Cancer
Natural killer cells reprogrammed inside mice eliminated lymphoma tumors and helped damaged livers heal, though whether this approach could help people with cancer or autoimmune disease remains unknown. To make a cancer treatment from [...]
Melanoma mRNA Vaccine Shows Promise in Preventing Disease Recurrence
Key takeaways: Phase 3 trial finds personalized intismeran plus pembrolizumab may better prevent high-risk melanoma recurrence after surgery The trial enrolled 1,137 patients and builds on phase 2 results showing about half the recurrence [...]
Scientists Discover a Powerful New Weapon Against a Dangerous Gut Infection
The promise of an experimental treatment for C. difficile gut infections lies partly in the bacteria it leaves alive, according to early laboratory and mouse research. Broad-spectrum antibiotics can disrupt the gut’s microbial community, [...]
Your Bones May Hold a Hidden Clue to Blood Cancer Survival
For people with blood cancers called myelodysplastic syndromes, osteoporosis may hold an overlooked clue to survival, a three-year observational study suggests. In blood cancers that develop in the bone marrow, an important clue to [...]
Researchers Discover What Reading for Pleasure May Be Doing to Your Brain
Reading for pleasure may offer surprising benefits for the brain, with research linking the habit to better mental health, stronger cognitive abilities, and a lower risk of dementia. Reading for pleasure may do far [...]
Scientists Discover a Hidden Trigger That Keeps Inflammation Alive
Inflammation persists after proteins detach from immune receptors, revealing a potential target for autoimmune treatments. Since a Nobel Prize-winning discovery in the 1990s identified molecules called Toll-like Receptors as the guardians of the human [...]
