- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Femtosecond-laser-written optofluidics in alumino-borosilicate glass
摘要： Femtosecond Laser Irradiation followed by Chemical Etching (FLICE) is a powerful technique for prototyping three-dimensional microfluidic structures in glass. Direct inscription of optical waveguides, by the same femtosecond laser, enables rapid fabrication of optofluidic devices for chemistry or biology applications. As a matter of fact, substrates where FLICE is known as most effective, such as fused silica, are not optimal for laser inscription of high-contrast optical waveguides, thus limiting the potentials of this technology. Here we show that it is possible to apply FLICE also to a commercial alumino-borosilicate glass, where very complex and low-loss photonic circuitry has been demonstrated recently. Besides optimizing the irradiation parameters to achieve hollow structures with high aspect-ratio, we investigate the etching dynamics and the micro-morphology of the etched regions. As a test for the technique, we realize an optofluidic device composed of a microchannel and two intersecting optical waveguides.
关键词： Borosilicate glass,Microfluidics,Femtosecond laser micromachining
更新于2025-09-12 10:27:22
-
[IEEE 2019 49th European Microwave Conference (EuMC) - Paris, France (2019.10.1-2019.10.3)] 2019 49th European Microwave Conference (EuMC) - Electrically Controlled Tunable Broadband Interferometric Dielectric Spectroscopy: Groundwork for Single Cell Analysis
摘要： An electrically controlled tunable interference based microwave sensor is demonstrated to perform time domain detection of single particles and measure complex permittivity of cell culture mediums within the broadband range of 12-18 GHz. Following set up is required to construct deep destructive interference nulls. Quadrature hybrid (QH), voltage controlled phase shifter and attenuator are utilized for each of the two branches. These comprise a reference branch and a branch containing the material-under-test (MUT). Coplanar waveguide (CPW) design was used as the microwave sensing structure and microfluidic wells were manufactured with polydimethylsiloxane (PDMS) to contain MUT, reference and calibration materials. The capability of detecting a single particle (diameter of 6-6.4um) is reported compared to simulations. Cell culture mediums measurements of Luria Agar (LA) and Luria Broth (LB) medium over the above-mentioned bandwidth were performed to demonstrate the operation processes and lay the groundwork for future research.
关键词： complex dielectric permittivity,microwave interferometry,microfluidics,spectroscopy,dielectric sensor
更新于2025-09-12 10:27:22
-
A disposable microfluidic-integrated hand-held plasmonic platform for protein detection
摘要： Healthcare is in the midst of a transformative shift from centralized care to point-of-care (POC). In this regard, recent efforts have focused on integration of biosensing technologies with clinical management and existing healthcare systems to improve the effectiveness and quality of care. Plasmonic technologies in particular, have been used for multiple applications in biosensing, pharmaceutical industry, food quality monitoring, and healthcare. However, bulky-sized platforms, expensive instrumentation, incomprehensive benchmarking, laborious protocols, and time-consuming processing steps remain challenges to adopt biosensing platforms to the POC settings. Here, we present a hand-held biosensing platform that integrates a plasmonic detection modality with a microfluidic chip. As a biological target model, we assess hemoglobin—an iron carrying protein in red blood cells. We comprehensively perform theoretical simulations and kinetic calculations to benchmark the platform performance. Overall, this miniaturized platform provides label-free detection, simple configuration for user-interface, facile sampling, assay-time down to 15–30 min, and inexpensive disposable chips. Therefore, this platform will potentially accelerate the deployment of portable biosensing systems for the POC and primary care settings.
关键词： Microfluidics,Point-of-care,Plasmonic sensors,Hemoglobin,Portable biosensors
更新于2025-09-11 14:15:04
-
Cellulose-Based Microparticles for Magnetically Controlled Optical Modulation and Sensing
摘要： Responsive materials with birefringent optical properties have been exploited for the manipulation of light in several modern electronic devices. While electrical fields are often utilized to achieve optical modulation, magnetic stimuli may offer an enticing complementary approach for controlling and manipulating light remotely. Here, the synthesis and characterization of magnetically responsive birefringent microparticles with unusual magneto-optical properties are reported. These functional microparticles are prepared via a microfluidic emulsification process, in which water-based droplets are generated in a flow-focusing device and stretched into anisotropic shapes before conversion into particles via photopolymerization. Birefringence properties are achieved by aligning cellulose nanocrystals within the microparticles during droplet stretching, whereas magnetic responsiveness results from the addition of superparamagnetic nanoparticles to the initial droplet template. When suspended in a fluid, the microparticles can be controllably manipulated via an external magnetic field to result in unique magneto-optical coupling effects. Using a remotely actuated magnetic field coupled to a polarized optical microscope, these microparticles can be employed to convert magnetic into optical signals or to estimate the viscosity of the suspending fluid through magnetically driven microrheology.
关键词： magneto-optical properties,polarized light,cellulose nanocrystals,microfluidics,microparticles
更新于2025-09-11 14:15:04
-
[IEEE 2018 Iranian Conference on Electrical Engineering (ICEE) - Mashhad (2018.5.8-2018.5.10)] Electrical Engineering (ICEE), Iranian Conference on - Theoretical and Simulational Study of Electrowetting on Dielectric (EWOD) Effect
摘要： Electrowetting mechanism has been recently employed to enhance the manipulation process in biomedical engineering. In this research, we have described the Electrowetting on thermodynamic Dielectric phenomenon by using classical approach. The droplet motion has been numerically studied by finite element method. The electrowetting mechanism has been investigated by solving the coupled electrostatic and droplet physics. Simulation results revealed 50 V threshold voltage for the system. The droplet velocity increases linearly by increasing the applied electric field and the maximum velocity of 0.04 mm/s has been achieved for 250 V excitation voltage. Based on the results, for the above 250 V there is no velocity increases.
关键词： Digital microfluidics,Electrowetting,Contact angle,Electrowetting on dielectric (EWOD),Surface tension,hydrophobic layer
更新于2025-09-11 14:15:04
-
Micromachined optical flow cell for sensitive measurement of droplets in tubing
摘要： Here a micromachined flow cell with enhanced optical sensitivity is presented that allows high-throughput analysis of microdroplets. As a droplet flows through multiple concatenated measurement points, the rate of enzymatic reaction in the droplet can be fully characterized without stopping the flow. Since there is no cross-talk between the droplets, the flow cell is capable of continuously measuring biochemical assays in a droplet flow and thus is suitable to be used for continuous point-of-care diagnostics monitoring. This paper describes the design and operation of the device and its validation by application to the accurate and continuous quantification of glucose concentrations using an oxidase enzymatic assay. The flow cell forms an important component in the miniaturization of chemical and bio analyzers into portable or wearable devices.
关键词： Enzymatic assays,Droplet microfluidics,Optical detections,Microfluidics,Real-time monitoring,Continuous measurement,Absorbance,Point-of-care diagnostics
更新于2025-09-10 09:29:36
-
One-step bonding and hydrophobic surface modification method for rapid fabrication of polycarbonate-based droplet microfluidic chips
摘要： Chip bonding and hydrophobic surface modification are two critical processes for the fabrication of a droplet microfluidic chip from the thermoplastic polycarbonate (PC) material. In this paper, we describe a novel one-step method, which simultaneously bonded and modified two PC substrates. The mechanism of this one-step method is that n-pentane acts as a sacrificial solvent and acetone is the solvent that bonds the PC substrates. Additionally, entrapment functionalization and the Si-O-Si cross-linked network play a central role in the hydrophobic surface modification process. The method was optimized to achieve a high bonding strength, low surface roughness, and high optical transmittance. The naturally hydrophilic PC substrate surface was modified to become a hydrophobic surface, with surface tension decreased from 33.6 mN/m to 14.8 mN/m. Monodisperse droplets generated using a droplet generation chip fabricated by this method had an average diameter of 101.3 μm and coefficient of variation of 0.55%. A droplet digital polymerase chain reaction experiment was successfully carried out using droplets generated from this chip, which demonstrated the effectiveness of this method. This novel one-step method holds great potential for manufacturing droplet-based microfluidic chips using PC in large-scale, and it may have broad applications in microfluidic research fields.
关键词： chip bonding,droplet digital PCR,entrapment functionalization,droplet microfluidics,hydrophobic surface modification
更新于2025-09-10 09:29:36
-
A Sample-to-Targeted Gene Analysis Biochip for Nanofluidic Manipulation of Solid-Phase Circulating Tumor Nucleic Acid Amplification in Liquid Biopsies
摘要： The use of circulating tumor nucleic acids (ctNA) in patient liquid biopsies for targeted genetic analysis is rapidly increasing in clinical oncology. Still, the call for an integrated methodology that is both rapid and sensitive for analyzing trace ctNA amount in liquid biopsies, has unfortunately not been fully realized. Herein, we performed complex liquid biopsy sample-to-targeted genetic analysis on a biochip with 50 copies-detection limit within 30 min. Our biochip uniquely integrated: 1) electrical lysis and release of cellular targets with minimal processing; 2) nanofluidic manipulation to accelerate molecular kinetics of solid-phase isothermal amplification; 3) single-step capture and amplification of multiple NA targets prior to nanozyme-mediated electrochemical detection. Using prostate cancer liquid biopsies, we successfully demonstrated multifunctionality for cancer risk prediction; correlation of serum and urine analyses; and cancer relapse monitoring.
关键词： solid-phase amplification,microfluidics,risk stratification,liquid biopsy,prostate cancer
更新于2025-09-10 09:29:36
-
Characterization and Integration of Terahertz Technology within Microfluidic Platforms
摘要： In this work, the prospects of integrating terahertz (THz) time-domain spectroscopy (TDS) within polymer-based microfluidic platforms are investigated. The work considers platforms based upon the polar polymers polyethylene terephthalate (PET), polycarbonate (PC), polymethyl-methacrylate (PMMA), polydimethylsiloxane (PDMS), and the nonpolar polymers fluorinated ethylene propylene (FEP), polystyrene (PS), high-density polyethylene (HDPE), and ultra-high-molecular-weight polyethylene (UHMWPE). The THz absorption coefficients for these polymers are measured. Two microfluidic platforms are then designed, fabricated, and tested, with one being based upon PET, as a representative high-loss polar polymer, and one being based upon UHMWPE, as a representative low-loss nonpolar polymer. It is shown that the UHMWPE microfluidic platform yields reliable measurements of THz absorption coefficients up to a frequency of 1.75 THz, in contrast to the PET microfluidic platform, which functions only up to 1.38 THz. The distinction seen here is attributed to the differing levels of THz absorption and the manifestation of differing f for the systems. Such findings can play an important role in the future integration of THz technology and polymer-based microfluidic systems.
关键词： lab-on-a-chip,THz time-domain spectroscopy,microfluidics,polymer absorption
更新于2025-09-10 09:29:36
-
Cell Density Detector Based on Light Beam Focusing
摘要： Although the lab-on-a-chip system has been successfully applied in a wide variety of fields, the goal of achieving a cell counter with simple operation, low cost, and high accuracy still attracts continuous research efforts. In this paper, the authors explore a cell counter based on light beam focusing to measure the density of adherent cells. In this sensor, the light emitted from the optical fibers is collimated by the collimating lens formed in polydimethylsiloxane (PDMS). The uniformly attached adherent cells act as a convex lens, focusing the collimated light propagated through them. The intensity of the focused light indicates the density of the adherent cells. For Hela cells, a detection limit of 8.3 × 104 cells/mL with a detection range from 0.1 × 106 cells/mL to 1.0 × 106 cells/mL is achieved. This sensor is particularly useful for drug screening, cell pathology analysis, and cancer pre-diagnosis.
关键词： cell counting,microfluidics system,light beam focusing
更新于2025-09-10 09:29:36