Water is a natural resource on which mankind depends and is used in many fields. In recent years, the patterning and flow control of trace amounts of water has attracted widespread attention in the fields of materials science, chemistry, and biomedicine.
"Cutting water with a knife"? September 1, the reporter was informed that the Xi'an Jiaotong University and Northwestern Polytechnical University research team collaborated to put forward the "laser cut water" new technology, and the realization of this idea, for the "water! "The application of water provides a new idea.
Laser cutting "water cake" made of various patterns.
Realization of cutting and processing of water by laser
How to "tame" water and put it to use has been a subject of study since ancient times. Cutting water, in people's eyes is an incredible thing, as the Tang Dynasty poet Li Bai's famous poem: "Drawing a knife to cut off the water more water, raise a cup to dispel the sadness more sad." As reflected in, water, as a fluid with disorder, is difficult to be plasticized and cut by traditional methods.
Nowadays, the main means of controlling the morphology and flow of trace water is to pre-process solid channels. However, due to the disordered nature and fluidity of water, precise machining of water is still challenging. Can laser cutting, as a technology that utilizes the photothermal effect to process solid materials, enable the cutting and processing of water?
Based on the above idea, Prof. Li Fei's group at the School of Life Sciences and Technology of Xi'an Jiaotong University and Associate Prof. Li Xiaoguang's group at the School of Physics of Northwestern Polytechnical University have collaborated to harness the laser, which is known as the "fastest knife", and adopt laser processing technology by regulating the fluidity and surface tension properties of water. Using laser processing technology, the team realized the idea of "laser cutting water" by adjusting the fluidity and surface tension properties of water, turning "cutting water with a knife" into a reality.
The team first used hydrophobic silica nanoparticles to coat the surface of water, constructing a "water cake" with a thickness of submillimeter, and then cut the "water cake" with a laser, successfully realizing the idea of "laser water cutting" and "laser water cutting". The idea of "laser cutting water" was successfully realized, and a variety of "patterns" were created.
Trace the reason why "water cake" can be cut
Why can the laser magically cut water? Team researchers, "water cake" can be cut by the laser for two main reasons: First, the "water cake" surface of the silica nanoparticles on the wavelength of 10.6 microns of infrared laser has a strong absorption, after laser irradiation, silica nanoparticles After laser irradiation, silica nanoparticles absorb laser energy converted to heat for water vaporization; second, when the local water is vaporized, the flow of water will drive the surface of the silica nanoparticles to further cover the exposed water surface, thus preventing the water "healing" process.
Li Fei introduction, the team also explored the volume of water through experiments on the "water cake" area, "water cake" thickness on the feasibility of cutting and "water cake" thickness, laser scanning speed on processing accuracy The optimized experimental parameters of "laser water cutting" were obtained. Subsequently, the laser cutter was applied to successfully process commonly used microfluidic chips, including cross channels and dispersed channels, confirming the ability of "laser water cutting" to process complex microfluidic structures, and determining that the microfluidic chips processed by "laser water cutting" can reach 350 micrometers at minimum. It has been determined that the smallest microfluidic chip processed by "laser water cutting" can be 350 micrometers.
The microfluidic chips prepared by "laser water-slicing" can be applied in many fields.
Fluid manipulation is one of the main applications of microfluidic chips and droplets. The team applied the microfluidic chips and droplets processed by "laser water slicing" for relevant fluid manipulation, and confirmed the fluid manipulation function of the prepared self-supported microfluidic chips and droplets.
In the course of the research, based on the openness of the "laser-cut water" processed microfluidic chip, the team applied the "laser-cut water" processed microfluidic chip as a miniaturized reaction platform to realize chemical synthesis. For example, copper-ammonia complexation and synthesis of amino acids with hydrated ninhydrin. Based on the light transmittance of the "laser-cut water" processed microfluidic chips, the team developed them as microreactors for biochemical sensing and colorimetric detection platforms for the detection of biomarkers such as metal ions, proteins, urea and nucleic acids. Finally, the processed microfluidic chips were used as patterned molds for electrokinetic manipulation of liquid metals and synthesis of patterned hydrogels, and as drug gradient dilution and cell culture platforms.
Through the research, the team innovatively proposed a technique for processing water by laser cutting, which solves the challenge of precisely processing water by binding the flow of water. Microfluidic chips prepared by laser-cutting water show potential for applications in a wide range of fields, including chemistry, health, materials science and biomedicine.
