A novel freeze-dissolving approach has been devised that offers greater efficiency and sustainability compared to the classic freeze-drying process to make superfine powder or nanoparticles.
In the research published in the journal ACS Sustainable Chemistry & Engineering, sphere-shaped ice particles were formed in an aqueous mixture of NH4H2PO4 or NaHCO3 to produce their respective nanoparticles.
What is the Freeze-Drying Method?
Due to their significant specific areas and strong reactivity, nanomaterials and superfine powders are gaining popularity in fields such as sustainable and environmental applications.
Nanoparticles (NPs) and superfine powders are often produced using freeze-drying techniques. The initial stage in the freeze-drying technique is a cryogenic procedure that freezes target particles or molecules in an aqueous mixture.
In the aqueous mixture, water molecules solidify quickly via the fast-freeze stage, generating a framework of crystallized ice. This step is also referred to as ice templating or freeze-casting. The crystallized ice framework forces the targeted dissolved molecules or components to produce a nanoscale scaffolding architecture, which results in substances with nanoscale or microscale pores.
The freezing stage defines the architecture of the scaffolding and the ice template, as well as the crystal architecture of the targeted substances inside the ice templates or scaffolds, based on the freezing settings.
The second phase is a drying procedure that uses the process of sublimation to separate water as ice templates. The ice melts throughout the drying phase, but the targeted substances, particles, or molecules stay within the ice. From inside the ice, freeze-cast NPs or porous substances with identical architecture and characteristics may be retrieved.
Schematic diagram of experimental setup for the freeze-dissolving method (top) and the freeze-drying method (bottom). © Yu, Q., Wang, Y., Luo, J., & Yang, H. (2022).
Limitations of Freeze-Drying
Due to the cooler temperatures employed in the drying phase, sublimation speeds are sluggish, and batch drying periods for common pharmacological items can take up to multiple days. The production speeds of such batch-based technologies are constrained by poor freeze-drying speeds and extended cycle operation durations.
Some drawbacks may be mitigated by purchasing a bigger freeze-dryer. Unfortunately, it takes much more time to establish perfect vacuum settings, and temperature and pressure are less consistent throughout the container, which could influence output quality. As a result of the cold temperatures and the vacuum arrangement, the drying phase consumes a lot of energy.
How is the Freeze-Dissolving Method Better?
The initial stage in freeze-dissolving is identical to that of freeze-drying, that is, freeze-casting to create ice containing the target components within and build an ice scaffold target architecture.
The ice is then dissolved at a cold temperature, such as a sub-zero temperature in an additional solvent having a low freezing point in the subsequent phase of the freeze-dissolving process. This additional solvent, like ethanol, acts as an antisolvent for the targeted components yet shows miscibility with water.
As a result, the ice scaffold will dissipate fast in the additional solvent, leaving just the targeted components in a solid-state in the mixture, and the architecture of the targeted components produced within the ice will be conserved.
Fire suppression chemicals, baking soda, ammonium dihydrogen phosphate (NH4H2PO4), and sodium bicarbonate (NaHCO3) are water-soluble but do not dissolve in ethanol.
In this work, various quantities of sodium bicarbonate or ammonium dihydrogen phosphate, dissolved in water, were employed to manufacture NPs via the freeze-dissolving technique, which were then evaluated against NPs produced by freeze-drying.
Schematic diagram of the freeze-dissolving and freeze-drying mechanisms for the formation and isolation of NaHCO3 nanoparticles. © Yu, Q., Wang, Y., Luo, J., & Yang, H. (2022).
Important Findings
To extract superfine powder and NPs from ice templates within frozen particles, the proposed freeze-dissolving process offers greater efficiency and sustainability compared to the conventional freeze-drying approach.
Particles of sodium bicarbonate and ammonium dihydrogen phosphate aqueous mixtures were quickly frozen to produce sphere-shaped ice particles, which were then filled with NPs and superfine powder of NaHCO3 or NH4H2PO4.
The frozen components were dispersed in ethanol for 5 minutes at 10 °C using the freeze-dissolving procedure to separate the ice scaffold. The freeze-drying approach, on the other hand, needed 1400 minutes to separate the ice scaffold via the process of sublimation. In identical experimental settings, the dimensions of the end products generated by the freeze-dissolving approach were comparatively small as opposed to those produced by the freeze-drying approach.
The freezing-dissolving approach reported in this study is approximately 100 times quicker and consumes roughly 100 times lesser energy as compared to the freeze-drying approach, without the need for a large facility or a vacuum. As a result, the freeze-dissolving process is likely to be used on an industrial scale with less time, energy, and footprint.
News
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 [...]
A Virus Gives Itself Away the Moment It Attacks
Researchers have found the trigger behind a powerful bacterial defense against viruses. Viruses that prey on bacteria could become an increasingly important tool for treating bacterial infections, particularly as antibiotic resistance makes some infections [...]
Scientists Discover Aspirin May Slash Dementia Risk by 70% – but Only for Certain People
Aspirin was linked to a sharply lower dementia risk in some older adults, and their genes may hold the clue. A Monash University analysis found that older adults with a particular genetic profile had [...]
Inflammation May Awaken Dormant Cancer Cells Years After Treatment
The body’s response to inflammation may disturb cancer cells that have been lying silent for years, giving them an opportunity to grow again. Researchers at the Francis Crick Institute have found that gut inflammation [...]
Where do nanoparticles go once they enter the body?
New international best practice guidance, co-written at ANSTO, sets out how to measure where nanoparticles like titanium dioxide end up in the body and how long they remain. The guidance has been shared by [...]
Long-Acting HIV Shots Could Solve a Major Treatment Challenge for Young People
A major African trial suggests that changing how HIV treatment is delivered could significantly improve viral suppression in adolescents. Young people with HIV were more likely to keep the virus suppressed when they received [...]
