全部國産に依る16ミリ「レ」線映晝 : 第2編

<div><p>Microfluidics is a great enabling technology for biology, biotechnology, chemistry and general life sciences. Despite many promising predictions of its progress, microfluidics has not reached its full potential yet. To unleash this potential, we propose the use of intrinsically active hydrogels, which work as sensors and actuators at the same time, in microfluidic channel networks. These materials transfer a chemical input signal such as a substance concentration into a mechanical output. This way chemical information is processed and analyzed on the spot without the need for an external control unit. Inspired by the development electronics, our approach focuses on the development of single transistor-like components, which have the potential to be used in an integrated circuit technology. Here, we present membrane isolated chemical volume phase transition transistor (MIS-CVPT). The device is characterized in terms of the flow rate from source to drain, depending on the chemical concentration in the control channel, the source-drain pressure drop and the operating temperature.</p></div

Overview of the fabrication procedure.

<p><b>Master fabrication:</b> (A) Lamination of dry film resist onto substrate. (B) Exposure with UV light through photo mask. (C) Post-exposure bake. (D) Development and rinsing with following hard bake. <b>Chip fabrication</b>: (E) Spin coating of PDMS on control layer master. (F) Moulding of PDMS on flow layer master. <b>Chip assembling</b>: (G) Inhibition of the channel break in the flow layer. (H) Plasma bonding with aligning of the PDMS layers. (I) Incorporation of the hydrogel particle into the control channel. (J) Plasma bonding of the multi-layer chip onto a cover glass.</p

Opening pressure extracted from the measurement data and modeled as a 2nd order 2D polynomial.

<p>Opening pressure extracted from the measurement data and modeled as a 2nd order 2D polynomial.</p

Dynamic investigation of the gate switching.

<p>(A), Experimental approach of the investigation. Switch event at t₀ carried out by a change of the input flow in the control channel from c₀ (= 0wt%) to c₁ (= 30wt%), while applying a constant pressure over the chemo-fluidic transistor. The flow rate generated in the flow channel is measured via a flow sensor. (B), Typical measurement of pressure and flow rate data over time, starting from time t₀ (= 0s). (C), Schematic graph with characteristic parameters to quantify the experimental data. (D), Bar graph of the characteristic parameter t₁₀, t₉₀ and Δt for three different dimensions of gel particles.</p

Transfer characteristic of the MIS-CVPT. Flow rate Q_DS over ethanol concentration c_Eth at a constant pressure p_DS = 100mbar for the temperatures <i>ϑ</i> 22.5°C; 25.0°C; 27.5°C; 30.0°C.

<p>Transfer characteristic of the MIS-CVPT. Flow rate Q_DS over ethanol concentration c_Eth at a constant pressure p_DS = 100mbar for the temperatures <i>ϑ</i> 22.5°C; 25.0°C; 27.5°C; 30.0°C.</p

3D-plot of measured output characteristics (flow rate Q_DS vs. pressure p_DS vs. ethanol concentration c_Eth) of the MIS-CVPT at different temperatures <i>ϑ</i> ranging from 22.5°C to 30.0°C in 2.5K steps.

<p>3D-plot of measured output characteristics (flow rate Q_DS vs. pressure p_DS vs. ethanol concentration c_Eth) of the MIS-CVPT at different temperatures <i>ϑ</i> ranging from 22.5°C to 30.0°C in 2.5K steps.</p

Measured output characteristics (flow rate Q_DS vs. pressure p_DS) of the MIS-CVPT with the different ethanol concentrations c_<i>Eth</i> 0wt%, 7.5wt%, and 15.0wt% at different temperatures <i>ϑ</i> ranging from 15.0°C to 30.0°C in 5.0K steps.

<p>Measured output characteristics (flow rate Q_DS vs. pressure p_DS) of the MIS-CVPT with the different ethanol concentrations c_<i>Eth</i> 0wt%, 7.5wt%, and 15.0wt% at different temperatures <i>ϑ</i> ranging from 15.0°C to 30.0°C in 5.0K steps.</p

Continuous Crystallization in a Helically Coiled Flow Tube: Analysis of Flow Field, Residence Time Behavior, and Crystal Growth

A continuously operated helically coiled flow tube (HCT) crystallizer is investigated for crystal growth. Inline video-imaging is used for crystal shape analysis and residence time estimation of potash alum. The main finding is that there is a size-dependent particle residence time. Large particles move faster through the HCT than small particles. Consequently, small crystals have more time to grow in the HCT. Physical reasons for this behavior are proposed, for example, small-scale flow characteristics. In a direct numerical simulation of the instationary Navier–Stokes equations, velocity fluctuations and a secondary flow are identified. The presented flow field may have a different impact on the particles and cause the size-dependent particle residence time. A particle size dependent residence time may potentially narrow the crystal size and shape distribution in such a process, frequently a desired feature in solids’ production

Electrically Tunable Dye Emission via Microcavity Integrated PDMS Gel Actuator

Electrically tunable microcavities are essential elements for tunable laser sources indispensable for modern telecommunication and spectroscopy. However, most device concepts suffer from extensive lithography or etching for membrane processing. Here, we present an electrically and continuously tunable, multi-half-wavelength microcavity with a quality factor > 1000 as an easy-to-fabricate platform with potential use for vertical-cavity surface-emitting lasers. The microcavity has a Fabry–Pérot structure consisting of ultrasoft PDMS gel with a thickness of 14–15 μm and capped by a distributed Bragg reflector on the bottom end and a silver layer serving as top mirror and electrode. Additionally, we have embedded a pyrromethene dye into the PDMS matrix to prove efficient gain medium integration. By means of an integrated dielectric elastomer actuator, the microcavity thickness is varied 1.3 μm (9%) with a driving voltage of 70 V. The subsequent silver mirror deflection achieves a reversible 40 nm tuning of the cavity resonance wavelength. The tuning range is limited by the lateral bending of the electrodes for increasing voltages. This characteristic bending is confirmed by simulations with finite elements method. The dynamic behavior of the microcavity is characterized by capacitance measurements and modeled by viscoelastic theory. Our research provides in-depth examinations of electrically tunable, PDMS gel-based microcavities with the future goal of building simple, miniaturized, and cost-efficient laser sources with high tuning range

Nonvasoconstrictive Hemoglobin Particles as Oxygen Carriers

Artificial oxygen carriers, favorably hemoglobin-based oxygen carriers (HBOCs), are being investigated intensively during the last 30 years with the aim to develop a universal blood substitute. However, serious side effects mainly caused by vasoconstriction triggered by nitric oxide (NO) scavenging due to penetration of nanosized HBOCs through the endothelial gaps of the capillary walls and/or oxygen oversupply in the precapillary arterioles due to their low oxygen affinity led to failure of clinical trials and FDA disapproval. To avoid these effects, HBOCs with a size between 100 and 1000 nm and high oxygen affinity are needed. Here we present for the first time unique hemoglobin particles (HbPs) of around 700 nm with high oxygen affinity and low immunogenicity using a novel, highly effective, and simple technique. The fabrication procedure provides particles with a narrow size distribution and nearly uniform morphology. The content of hemoglobin (Hb) in the particles corresponded to 80% of the Hb content in native erythrocytes. Furthermore, we demonstrate a successful perfusion of isolated mouse glomeruli with concentrated HbP suspensions <i>in vitro</i>. A normal, nonvasoconstrictive behavior of the afferent arterioles is observed, suggesting no oxygen oversupply and limited NO scavenging by these particles, making them a highly promising blood substitute