Akustisk anrikning av mikropartiklar i droppar

Acoustophoresis is a label free method where the acoustic radiation force is used to manipulate microparticles inside microfluidic channels. The magnitude of the force is dependent of several parameters, which include the density, speed of sound and size of the microparticles, as well as the amplitude of the pressure waves. Recently, acoustophoresis has been used in microfluidics to manipulate microparticles inside moving droplets. In this Master's thesis project, two microfluidic chip designs are used to enrich droplets with polystyrene beads (10 μm in diameter) using acoustophoresis. The microchips have been fabricated with two different fabrication methods; crystalline dependent wet etching and crystalline independent dry etching. In the microchips, water droplets in oil are generated with microparticles suspended in them. By using a channel width that is half a wavelength of the incoming acoustic waves, pressure nodal lines are created in the middle of the channel in which the microparticles align. The droplets then enters a droplet splitting feature, where they are divided into three daughter droplets. Since the majority of the incoming particles are recovered in the center daughter droplet while some of the droplet volume is removed, the center droplet is enriched with the microparticles. For the wet etched design stable droplet splitting was observed when the volumetric flow was 18 μL/min and the incoming droplets had a length-to-width ratio larger than 3. The maximum recovery for this design was 81.1% ± 13.8% with an applied voltage at 10 Vpp. Stable droplet splitting was observed for the dry etched chip at 10.5 μL/min and 18 μL/min at 10 and 20 Vpp, when the incoming droplet had a length-to-width ratio of 3. In this chip the maximum recovery was 93.2% ± 8.3% at the volumetric flow of 10.5 μL/min and an applied voltage of 20 Vpp

Akustisk anrikning av mikropartiklar i droppar

Acoustophoresis is a label free method where the acoustic radiation force is used to manipulate microparticles inside microfluidic channels. The magnitude of the force is dependent of several parameters, which include the density, speed of sound and size of the microparticles, as well as the amplitude of the pressure waves. Recently, acoustophoresis has been used in microfluidics to manipulate microparticles inside moving droplets. In this Master's thesis project, two microfluidic chip designs are used to enrich droplets with polystyrene beads (10 μm in diameter) using acoustophoresis. The microchips have been fabricated with two different fabrication methods; crystalline dependent wet etching and crystalline independent dry etching. In the microchips, water droplets in oil are generated with microparticles suspended in them. By using a channel width that is half a wavelength of the incoming acoustic waves, pressure nodal lines are created in the middle of the channel in which the microparticles align. The droplets then enters a droplet splitting feature, where they are divided into three daughter droplets. Since the majority of the incoming particles are recovered in the center daughter droplet while some of the droplet volume is removed, the center droplet is enriched with the microparticles. For the wet etched design stable droplet splitting was observed when the volumetric flow was 18 μL/min and the incoming droplets had a length-to-width ratio larger than 3. The maximum recovery for this design was 81.1% ± 13.8% with an applied voltage at 10 Vpp. Stable droplet splitting was observed for the dry etched chip at 10.5 μL/min and 18 μL/min at 10 and 20 Vpp, when the incoming droplet had a length-to-width ratio of 3. In this chip the maximum recovery was 93.2% ± 8.3% at the volumetric flow of 10.5 μL/min and an applied voltage of 20 Vpp

Akustisk anrikning av mikropartiklar i droppar

Acoustophoresis is a label free method where the acoustic radiation force is used to manipulate microparticles inside microfluidic channels. The magnitude of the force is dependent of several parameters, which include the density, speed of sound and size of the microparticles, as well as the amplitude of the pressure waves. Recently, acoustophoresis has been used in microfluidics to manipulate microparticles inside moving droplets. In this Master's thesis project, two microfluidic chip designs are used to enrich droplets with polystyrene beads (10 μm in diameter) using acoustophoresis. The microchips have been fabricated with two different fabrication methods; crystalline dependent wet etching and crystalline independent dry etching. In the microchips, water droplets in oil are generated with microparticles suspended in them. By using a channel width that is half a wavelength of the incoming acoustic waves, pressure nodal lines are created in the middle of the channel in which the microparticles align. The droplets then enters a droplet splitting feature, where they are divided into three daughter droplets. Since the majority of the incoming particles are recovered in the center daughter droplet while some of the droplet volume is removed, the center droplet is enriched with the microparticles. For the wet etched design stable droplet splitting was observed when the volumetric flow was 18 μL/min and the incoming droplets had a length-to-width ratio larger than 3. The maximum recovery for this design was 81.1% ± 13.8% with an applied voltage at 10 Vpp. Stable droplet splitting was observed for the dry etched chip at 10.5 μL/min and 18 μL/min at 10 and 20 Vpp, when the incoming droplet had a length-to-width ratio of 3. In this chip the maximum recovery was 93.2% ± 8.3% at the volumetric flow of 10.5 μL/min and an applied voltage of 20 Vpp

A Comparison of a Novel Stretchable Smart Patch for Measuring Runner's Step Rates with Existing Measuring Technologies

A novel wearable smart patch can monitor various aspects of physical activity, including the dynamics of running, but like any new device developed for such applications, it must first be tested for validity. Here, we compare the step rate while running in place as measured by this smart patch to the corresponding values obtained utilizing ''gold standard'' MEMS accelerometers in combination with bilateral force plates equipped with HBM load cells, as well as the values provided by a three-dimensional motion capture system and the Garmin Dynamics Running Pod. The 15 healthy, physically active volunteers (age = 23 +/- 3 years; body mass = 74 +/- 17 kg, height = 176 +/- 10 cm) completed three consecutive 20-s bouts of running in place, starting at low, followed by medium, and finally at high intensity, all self-chosen. Our major findings are that the rates of running in place provided by all four systems were valid, with the notable exception of the fast step rate as measured by the Garmin Running Pod. The lowest mean bias and LoA for these measurements at all rates were associated consistently with the smart patch