(Press-News.org)
< Overview >
Researchers at Toyohashi University of Technology in Japan, in collaboration with the Institute of Translational Medicine and Biomedical Engineering (IMTIB) in Argentina and the Indian Institute of Technology Madras, have advanced the "PDMS SlipChip," a versatile microfluidic device. By using a low-viscosity silicone oil and fine-tuning the fabrication process, they've made the SlipChip more reliable for cell-based experiments and simpler for creating concentration gradients. This breakthrough tackles previous issues like channel clogging and potential harm to cells, opening new avenues for biomedical research, including drug development and sophisticated cell studies.
< Details >
Microfluidic "SlipChips" are clever tools that allow scientists to manipulate tiny amounts of liquid without needing complex pumps or valves. A key feature is their ability to mix different solutions on the chip to easily form step-by-step concentration gradients—ideal for testing how cells respond to varying drug doses, for example, while using minimal precious samples.
PDMS (a type of silicone) has become a preferred material for SlipChips due to its excellent flexibility, gas permeability, and biocompatibility with cells. However, getting the "slip" just right between the PDMS layers using a lubricant (silicone oil) without causing leaks or blockages, and ensuring the PDMS itself is optimally prepared, has been a tricky balance. Traditionally, thicker (high-viscosity) oils were used to prevent leaks, but they often clogged the tiny channels and could be harmful to cells. Thinner (low-viscosity) oils were less prone to clogging, but didn't seal as well.
The research team, led by Professor Moeto Nagai from Toyohashi University of Technology, found a smart solution. They focused on a low-viscosity silicone oil (50 cSt) and optimized the PDMS curing temperatures. Rafia Inaam, the study's first author, explains, "We discovered that how you cure the PDMS affects both how well the layers stick together and the material's overall stiffness. Our 'two-step curing approach'—heating the top layer to 80°C and the bottom to 60°C—struck the perfect balance. This allows for smooth slipping with the low-viscosity oil, without leaks or blockages."
This optimized PDMS SlipChip performs reliably. It maintains a strong seal even with the thinner oil, preventing leaks, and the channels remain clear. When tested with human osteosarcoma cells (a type of cancer cell), the 50 cSt oil showed excellent cell compatibility, with 95% of cells remaining viable—comparable to standard cell culture methods. This overcomes a major concern with previous high-viscosity oils.
"This practical optimization of the oil and curing process has solved a long-standing challenge for PDMS SlipChips, achieving both high performance and safety," says Professor Nagai. "This makes cell cultures more reliable and also means we can use the SlipChip’s powerful ability to create concentration gradients. We believe this will greatly benefit a wide range of research, from fundamental cell biology to applied drug discovery."
< Future Outlook >
The team is now exploring more complex applications for their optimized PDMS SlipChip. This includes using it for sophisticated mammalian cell experiments, such as testing cellular responses to drug concentration gradients created directly on the chip, and studying cell-to-cell interactions. They also envision its use in advanced bio-analytical tasks like protein detection. This improved SlipChip technology could contribute to personalized medicine by enabling more efficient drug screening and advancing cell manipulation techniques in regenerative medicine.
< Publication Information >
Rafia Inaam, Marcela F. Bolontrade, Shunya Okamoto, Takayuki Shibata, Tuhin Subhra Santra and Moeto Nagai, “PDMS SlipChip: Optimizing Sealing, Slipping, and Biocompatibility Using Low-Viscosity Silicone Oils”, Micromachines, 2025, Vol. 16, Issue 5, 525. DOI: 10.3390/mi16050525 (Published: 29 April 2025)
< Funding >
This research was funded by the Kayamori Foundation of Informational Science Advancement; the Japan Society for the Promotion of Science (JSPS), under Grant Numbers 23KK0070 and 23H00168; and the Toyota Physical and Chemical Research Institute through the Toyota Riken Scholar Program.
END
A study by Dartmouth researchers proposes a new theory about the origin of dark matter, the mysterious and invisible substance thought to give the universe its shape and structure.
The researchers report in Physical Review Letters that dark matter could have formed in the early life of the universe from the collision of high-energy massless particles that lost their zip and took on an incredible amount of mass immediately after pairing up, according to their mathematical models.
While hypothetical, dark matter is believed to exist based on observed gravitational effects that cannot be explained by visible matter. Scientists ...
"I'm stunned." says Per Ahlberg of Uppsala University, who coordinated the study; "A single track-bearing slab, which one person can lift, calls into question everything we thought we knew about when modern tetrapods evolved."
The story of the origin of tetrapods began with fishes leaving the water, and ended with the descendants of these first colonists on land diversifying into the ancestors of the modern amphibians and amniotes (the group that includes reptiles, birds and mammals). ...
Xiaowei Gu and Joshua Johansen at the RIKEN Center for Brain Science in Japan have discovered key circuitry in the rat brain that allows the learning of inferred emotions. The study reveals how the frontal part of the brain coordinates with the amygdala—a brain region important for simple forms of emotional learning—to make this higher-order emotional ability possible. Published in the scientific journal Nature on May 14, this breakthrough study is the first to show how the brain codes human-like internal models of emotion.
What are inferred emotions? Consider a child who often watches a wasp fly in and out of its nest in the woods near her house. One day the child ...
The human gut is home to trillions of microbes that not only aid in digestion but also play a key role in shaping our immune system. These microbes communicate with the body by releasing a range of molecules that influence how immune cells grow and function.
To maintain a healthy balance between host defense and microbial coexistence, the body deploys a variety of defense tools—such as mucus, antimicrobial proteins, antibodies, and complement proteins—to control microbial activity and fend off harmful invaders. But one mystery has lingered: Can our bodies selectively recognize and manage specific bacteria among this incredibly diverse microbial community?
In ...
Neuroscientists at the Sainsbury Wellcome Centre (SWC) at UCL have discovered that the brain uses a dual system for learning through trial and error. This is the first time a second learning system has been identified, which could help explain how habits are formed and provide a scientific basis for new strategies to address conditions related to habitual learning, such as addictions and compulsions. Published today in Nature, the study in mice could also have implications for developing therapeutics for Parkinson’s.
“Essentially, we have found a mechanism that we think is responsible for habits. Once you have developed a preference for a certain action, ...
A new scientific study identified taurine, which is made naturally in the body and consumed through some foods, as a key regulator of myeloid cancers such as leukemia, according to a paper published in the journal Nature.
The preclinical research shows that scientists are a step closer to finding new ways to target leukemia, which is one of the most aggressive blood cancers. The Wilmot Cancer Institute investigators at the University of Rochester were able to block the growth of leukemia in mouse models and in human leukemia cell samples by using genetic tools to prevent taurine from entering cancer ...
What: Researchers at the National Institutes of Health (NIH) have identified a series of changes in the architecture and cell composition of connective tissues of the breast, known as stromal tissue, that is associated with an increased risk of developing aggressive breast cancer among women with benign breast disease, and poorer rates of survival among women with invasive breast cancer. This process, which they call stromal disruption, could potentially be used as a biomarker to identify women with benign breast disease ...
About The Study: In patients with overweight/obesity and/or diabetes, glucagon-like peptide 1 receptor agonist (GLP1-RA) treatment is not associated with increased risk of psychiatric adverse events or worsening depressive symptoms relative to placebo and is associated with improvements in quality of life, restrained eating, and emotional eating behavior. These findings provide reassurance regarding the psychiatric safety profile of GLP1-RAs and suggest that GLP1-RA treatment contributes to both physical and emotional well-being.
Corresponding Authors: To contact the corresponding authors, email Aureliane C. S. Pierret, ...
About The Study: In this cross-sectional study of cannabis use in veterans ages 65 to 84, use was common, and more than one-third who used in the past 30 days had any cannabis use disorder. The prevalence of past 30-day cannabis use was close to tobacco use prevalence, and risk factors for cannabis use were similar to those observed in other populations. Frequent and inhaled cannabis use was associated with higher odds of any cannabis use disorder. Routine health screening for cannabis use in Veterans Health Administration clinical settings is necessary ...
A first-of-its-kind study in Nature finds that with bold and coordinated policy choices—across emissions, diets, food waste, and water and nitrogen efficiency—humanity could, by 2050, bring global environmental pressures back to levels seen in 2015. This shift would move us much closer to a future in which people around the world can live well within the Earth’s limits. “Our results show that it is possible to steer back toward safer limits, but only with decisive, systemic change,” says lead author Prof Detlef Van Vuuren, a researcher at Utrecht University and the Netherlands Environmental Assessment Agency (PBL).
The ...
