Microfluidic Chip Device Research Articles

The Formation Mechanism of Residual Oil and Methods of Enhanced Oil Recovery in a Fractured Low-Permeability Metamorphic Rock Reservoir in Bohai Bay

The oil reservoirs of the metamorphic rocks in Bohai Bay have geological characteristics such as low matrix porosity and permeability, developed natural microfractures, which result in the injection water rapidly advancing along fractures, a fast increase in the water content, and difficulties in extracting the remaining oil. In order to reveal water channeling and the residual oil formation mechanisms in fractured low-permeability reservoirs and solve the water channeling problem, we first analyzed the reservoir development status, then studied the formation mechanism of residual oil using a microfluidic chip device, and formed a method of hierarchical control to effectively control the water channeling problem of fractured reservoirs and maximize the displacement of residual oil. The results show that (1) Due to the low permeability of the reservoir matrix, a large amount of injected water flows along the fracture channel, which leads to the long-term high water cut of some oil wells and the retention of a large amount of crude oil in the matrix. (2) The results of microfluidic experiments show that the distribution of residual oil after water flooding mainly includes five types: blind end of the pore throat, columnar, cluster, flake and film, and residual oil. Among them, sheet-like and clustered residual oil are dominant, accounting for 75~85% and 10~13%, respectively. (3) Based on the characteristics of fracture development in buried-hill reservoirs, a hierarchical control technology of “gel particle + liquid crosslinked gel system” is established. The field application effect predicted that the input–output ratio was 1:3. This study provides a reference for the comprehensive treatment of water channeling in the same type of offshore fractured low-permeability metamorphic rock reservoirs.

Lab-on-a-chip paper-based electrochemically assisted solid-phase microextraction and ion selective sensor for determination of naproxen in biological fluid samples

BackgroundThe integration of paper-based analytical devices with lab-on-a-chip technology has opened up new possibilities for miniaturized, rapid, low cost and portable diagnostic testing in resource limited settings. This work introduces an integrated lab-on-a-chip platform coupling paper-based analytical devices (LOC-PADs) for dual usage: electrochemically controlled solid-phase microextraction (EC-SPME) and determination of naproxen (NAP) by potentiometric ion-selective electrode (ISE) in biological samples. ResultsConductive papers were successfully fabricated by a chemical procedure. Thereupon, a conducting molecularly imprinted polymer (CMIP) film based on PPy and an anionic model drug (NAP) as a template were applied to the conductive paper substrate via electrochemical methods. A microfluidic chip device was employed to assess the analytical performance of the fabricated paper-based CMIP. The designed chip is divided into two parts with a microfluidic channel between them. The first chamber is an extraction zone for EC-SPME of NAP by using the CMIP paper as a selective sorbent. The second chamber is the detection zone and consists of a paper-based NAP ion selective sensor for potentiometric detection of drug. The analytical process was investigated and optimized for each chamber. Remarkable selectivity towards NAP was achieved in the concentration range from 4.0 × 10−7 to 1.0 × 10−2 mol L−1 with determination coefficient (R2 = 0.99) and the limit of detection (LOD) was 2.0 × 10−7 mol L−1. Anionic Nernstian compliance was gained −58.5 ± 0.5 mV decade−1, and response time in the detection step was 7s for ISE. Satisfactory spiking recovery values within the acceptable range of 90–110 % with RSDs ≤7 % were achieved for the analysis of real samples with fully portable LOC device. SignificanceThe LOC-PADs were favorably used for selective extraction and determination of NAP in serum and saliva samples, respectively. EC-SPME caused sample clean-up, reduced or eliminated different interferences and enhanced selective response of ISE as detection zone of device. Integration of EC-SPME and ISE in a single chip enabled easy and fast determination of trace amounts of NAP in limited real sample volumes, and fully portable advantages.

Machine Learning-Driven Prediction of DLD Chip Throughput

Abstract The microfluidic chip technology, capable of manipulating fluids at the micrometer-scale, is increasingly being applied in the fields of cell biology, molecular biology, chemistry, and life sciences. The densely integrated microfluidic chip devices enable high-throughput parallel experiments and integration of various operational units. However, the development of densely integrated microfluidic chips also comes with high demands on driving equipment. Due to manufacturing processes and inherent design limitations, the driving capability of the equipment is restricted. To address potential challenges faced by microfluidic chips in the development towards integrated biological microsystems and to maximize their high-throughput performance, improvements are required not only in selecting appropriate driving equipment but also in design aspects. This study focuses on the DLD chip and delves into the complexity of microfluidic chip design. By combining Bézier curves to characterize arbitrarily shaped micropillars and conducting finite element analysis to compute the pressure field of DLD chips, we explore methods utilizing random forest, XGBoost, LightGBM, and ANN machine learning algorithms to predict the impedance of DLD chips. Our objective is to guide engineers in designing chips with smaller impedance (lower pressure drop) and larger throughput more quickly and efficiently during the design phase. Ultimately, through evaluating the predictive capabilities of the four models on new data, we select the ANN algorithm model to predict the pressure drop under different designs of DLD chips. This offers possibilities for enhancing the efficiency and integration of microfluidic technology in biomedical applications.

Design of membrane-based microfluidic chip device based on bionic leaf and adsorption detection of tetracycline antibiotics by specific gel membrane

In this study, we developed copper alginate-carbon nanotube/copper sulfide-graphene oxide gel membranes based on the design inspired by the surface structure of leaves and plant transpiration in nature and through the modulation of high-density polymer networks. This light-driven water evaporation-specific adsorption gel membrane is capable of using solar energy to drive water evaporation from contaminated surface water to access tetracycline antibiotics for detection. Combined with the designed biomimetic adsorption detection chip, in situ monitoring of tetracycline antibiotics in water bodies was achieved. Compared with the traditional mass spectrometry detection method, it shows more outstanding performance in terms of time, environmental protection and technology. The microscale adsorption mechanism was further explored on the molecular scale by density functional theory (DFT). The results showed that tetracycline antibiotics were adsorbed on the aerogel membrane mainly through π-πEDA interactions in sandwich (S) configuration and parallel displacement (PD) configuration, which ensured high adsorption efficiency. Under the optimized conditions, the tetracycline concentration detected by the sensor showed a good linear relationship with the cyclic voltammetry curve, and the lowest detection limit was 1.59*10−4 μM. This adsorption detection strategy can reduce the influence of organic matter, inorganic matter, and other classes of antibiotics on the detection of tetracycline antibiotics, and provide a new idea for the high-efficiency photo-thermal actuation and in-situ testing of tetracycline antibiotics.

Low dissipative configuration in flow networks subject to constraints

The homothetic relationships for the design of dendritic networks are examined in terms of minimal size under constant flow resistance, and minimum flow resistance under constant size. Based on a comprehensive methodology, we offer a general approach for the homothety ratios of diameters and lengths that apply to different flow regimes and size constraints. In addition, scaling laws for diameters-lengths, sizes-diameters, and resistances-lengths are provided. Since the dendritic trees designed based on size homothety ratios have prefractal characteristics, a methodology for determining prefractal dimensions in terms of fluid flow and size constraint characteristics is also offered. Among the findings, we show that the homothety ratios are the same regardless of whether the functions we selected are used as the constraint or the cost function. The approaches presented and literature data were compared, and a significant degree of agreement was found.The findings presented here not only serve as a tool for the design of microfluidic chip devices but also deepen our understanding of natural networks such as the ones that support the life of mammals.

Integrated High-Throughput Centrifugal Microfluidic Chip Device for Pathogen Detection On-Site.

An integrated and high-throughput device for pathogen detection is crucial in point-of-care testing (POCT), especially for early diagnosis of infectious diseases and preventing the spread of infection. We developed an on-site testing platform that utilizes a centrifugal microfluidic chip and automated device to achieve high-throughput detection. The low-power (<32 W), portable (220 mm × 220 mm × 170 mm, 4 kg) device can complete bacterial lysis, nucleic acid extraction and purification, loop-mediated isothermal amplification (LAMP) reaction, and real-time fluorescence detection. Magnetic beads for nucleic acid adsorption can be mixed by applying electromagnetic fields and centrifugal forces, and the efficiency of nucleic acid extraction is improved by 60% compared to the no-mixing group. The automated nucleic acid extraction process achieves equivalent nucleic acid extraction efficiency in only 40% of the time consumed using the kit protocol. By designing the valve system and disc layout, the maximum speed required for the centrifugal microfluidic chip is reduced to 1500 rpm, greatly reducing the equipment power consumption and size. In detecting E. coli, our platform achieves a limit of detection (LOD) of 102 CFU/mL in 60 min. In summary, our active centrifugal microfluidic platform provides a solution for the integration of complex biological assays on turntables, with great potential in the application of point-of-care diagnosis.

A centrifugal microfluidic system for automated detection of multiple heavy metal ions by aptamer-based colorimetric assay

The contamination of aquatic environments with heavy metal ions is characterized by their resistance to natural degradation, leading to their bioaccumulation in plants and animals, consequently posing a significant threat to human health. The detection of toxic metal ions is of great significance in environmental protection and disease prevention. In this work, a rapid and automated method for the simultaneous detection of Pb2+, Hg2+ and As3+ in water was proposed. An aptamer-based colorimetric assay and a centrifugal microfluidic chip to realize the function of sampling, mixing, reaction etc. The microfluidic chip and centrifugal device were properly designed and developed. Besides, the detection parameters were optimized by analyzing the sensitivity and selectivity. Results showed that the detection system was able to realize the automatic detection of the multiple heavy metal ions within 30 min, and the limits of detection for Pb2+, Hg2+ and As3+ were 6.16 ppb, 4.97 ppb and 5.24 ppb. The self-developed system can be utilized as a promising platform for the rapid detection of multiple heavy metal ions in practical applications.

ZIF67-derived porous carbon-reinforced electrospun nanofiber as an extractive phase for on-chip micro-solid-phase extraction of antifungals from biological fluids prior to liquid chromatography tandem mass spectrometry.

With a view to improving applicability as a sorbent while overcoming the challenges associated with its powdery nature, cobalt-doped zeolitic imidazolate framework (ZIF 67)-derived nanoporous carbon (Co-NPC) was employed as an additive in nanofiber through the process of electrospinning. X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and Brunauer-Emmett-Teller (BET) surface area analysis were used to characterize the resulting nanocomposite. A microfluidic chip device with four layers, including two layers entailing spiral channels, was designed and employed to assess the analytical performance of the fabricated Co-NPC-reinforced electrospun composite. To do so, a folded piece of electrospun composite was sandwiched between two layers with spiral channels. Therefore, both sides of the folded composite acted as a sorptive phase to extract antifungal drugs as target analytes. The significant factors affecting the efficiency of the extraction process were investigated and optimized. Subsequently, the technique was verified through the utilization of liquid chromatography-tandem mass spectrometry (LC-MS/MS) by employing optimal parameters. The optimal conditions were applied to evaluate the figures of merit. A linear range was obtained for antifungal drugs within the range 0.25-200.0ngml-1 with an R2 value of ≥ 0.9914. The method demonstrated detection limits ranging between 0.08 and 0.40ngml-1. The intra-day and inter-day precisions were less than 6.9%. Relative recoveries exhibited variations between 91.4-106.8%, 95.9-103.6%, and 96.4-109.3% for ketoconazole, clotrimazole, and miconazole, respectively. The proposed approach yielded satisfactory results, demonstrating its efficiency.

Designing Microfluidic PCR Chip Device Using CFD Software for the Detection of Malaria

Polymerase chain reaction (PCR) technique is one of the molecular methods in amplifying DNA for the detection of malaria. However, the collection and transportation of samples and the processing and dissemination of results via conventional PCR, especially when used for routine clinical practice, can hamper the technique’s sensitivity and specificity. The rampancy of such disease in the Philippines is aggravated by the limited supply of medical machinery and the poor economic state of the country; thus, the need to innovate a device for the early detection of malaria is necessary. With that, this study focuses on designing a microfluidic device that will mimic the function of a conventional genus-specific PCR based on the 18S rRNA gene to detect malaria parasites (Plasmodium falciparum) at low-grade parasitemia. The design was intended to be portable, accessible, and economical, which none from past literature has dealt with specifically for malaria detection. This in silico design is a first in the country specially crafted for such reasons. The proposed device was developed and simulated using ANSYS software for Computational Fluid Dynamics (CFD) analyses. The simulation shows that adding loops to the design increases its relative deviation but minimally compared to having only a straight path design. This indicates that looping is acceptable in designing a microfluidic device to minimize chip length. It was also found that increasing the cross-sectional area of the fluid path decreases the efficiency of the design. Lastly, among the three materials utilized, the chip made of polypropylene is the most efficient, with a relative deviation of 0.94 compared to polycarbonate and polydimethylsiloxane, which have relative deviations of 2.78 and 1.92, respectively. Future researchers may mesh the 44-cycle microfluidic chip due to the limitations of the software used in this study, and other materials, such as biocomposites, may be assessed to broaden the application of the design.

Bisphosphonates attenuate age-related muscle decline in Caenorhabditis elegans.

Age-related muscle decline (sarcopenia) associates with numerous health risk factors and poor quality of life. Drugs that counter sarcopenia without harmful side effects are lacking, and repurposing existing pharmaceuticals could expedite realistic clinical options. Recent studies suggest bisphosphonates promote muscle health; however, the efficacy of bisphosphonates as an anti-sarcopenic therapy is currently unclear. Using Caenorhabditis elegans as a sarcopenia model, we treated animals with 100nM, 1, 10, 100 and 500μM zoledronic acid (ZA) and assessed lifespan and healthspan (movement rates) using a microfluidic chip device. The effects of ZA on sarcopenia were examined using GFP-tagged myofibres or mitochondria at days 0, 4 and 6 post-adulthood. Mechanisms of ZA-mediated healthspan extension were determined using combined ZA and targeted RNAi gene knockdown across the life-course. We found 100nM and 1μM ZA increased lifespan (P<0.001) and healthspan [954±53 (100nM) and 963±48 (1μM) vs. 834±59% (untreated) population activity AUC, P<0.05]. 10μM ZA shortened lifespan (P<0.0001) but not healthspan (758.9±37 vs. 834±59, P>0.05), whereas 100 and 500μM ZA were larval lethal. ZA (1μM) significantly improved myofibrillar structure on days 4 and 6 post-adulthood (83 and 71% well-organized myofibres, respectively, vs. 56 and 34% controls, P<0.0001) and increased well-networked mitochondria at day 6 (47 vs. 16% in controls, P<0.01). Genes required for ZA-mediated healthspan extension included fdps-1/FDPS-1 (278±9 vs. 894±17% population activity AUC in knockdown+1μM ZA vs. untreated controls, respectively, P<0.0001), daf-16/FOXO (680±16 vs. 894±17%, P<0.01) and agxt-2/BAIBA (531±23 vs. 552±8%, P>0.05). Life/healthspan was extended through knockdown of igdb-1/FNDC5 (635±10 vs. 523±10% population activity AUC in gene knockdown vs. untreated controls, P<0.01) and sir-2.3/SIRT-4 (586±10 vs. 523±10%, P<0.05), with no synergistic improvements in ZA co-treatment vs. knockdown alone [651±12 vs. 635±10% (igdb-1/FNDC5) and 583±9 vs. 586±10% (sir-2.3/SIRT-4), both P>0.05]. Conversely, let-756/FGF21 and sir-2.2/SIRT-4 were dispensable for ZA-induced healthspan [630±6 vs. 523±10% population activity AUC in knockdown+1μM ZA vs. untreated controls, P<0.01 (let-756/FGF21) and 568±9 vs. 523±10%, P<0.05 (sir-2.2/SIRT-4)]. Despite lacking an endoskeleton, ZA delays Caenorhabditis elegans sarcopenia, which translates to improved neuromuscular function across the life course. Bisphosphonates might, therefore, be an immediately exploitable anti-sarcopenia therapy.

Computational analysis of ternary nanofluid flow in a microchannel with nonuniform heat source/sink and waste discharge concentration

The investigation of waste discharge concentration with microchannel plays a significant impact on environmental applications. Microchannels are utilized in treatment facilities for wastewater to manage the concentration of pollutants and impurities. Effective waste treatment and pollution control techniques may be created by investigating waste material’s fluid flow and dispersion in microchannels. In view of the above applications, the present investigation examines the electrically conducting and incompressible ternary hybrid nanofluid movement in a microchannel with a nonuniform heat source/sink and waste discharge concentration. The governing equations are converted into a system of ordinary differential equations using appropriate similarity constraints, and the resulting equations are numerically solved using the RKF-45 (Runge Kutta Fehlberg 4th and 5th) method. The effects of different nondimensional limitations are visually displayed and thoroughly explored on flow patterns, heat distribution, and concentration profiles. The analysis is done on important engineering variables such as skin friction, heat transfer rate, and mass transfer. Magnetic and porous media shape factors directly influenced the velocity and temperature profiles. These two factors will decline the velocity and improve the temperature. Further, the improvement in local and external pollutant concentration will improve the concentration of the fluid. The rate of mass transfer improves with increasing the local external source constraint. The present work outcomes are helpful in heat exchangers, pollution control, microfluidic chip devices, wastewater treatment, and energy conversion.

Microfluidic fabricated bisdemethoxycurcumin thermosensitive liposome with enhanced antitumor effect

Bisdemethoxycurcumin (BDMC) is the main active ingredient that is isolated from Zingiberaceae plants, wherein it has excellent anti-tumor effects. However, insolubility in water limits its clinical application. Herein, we reported a microfluidic chip device that can load BDMC into the lipid bilayer to form BDMC thermosensitive liposome (BDMC TSL). The natural active ingredient glycyrrhizin was selected as the surfactant to improve solubility of BDMC. Particles of BDMC TSL had small size, homogenous size distribution, and enhanced cultimulative release in vitro. The anti-tumor effect of BDMC TSL on human hepatocellular carcinomas was investigated via 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method, live/dead staining, and flowcytometry. These results showed that the formulated liposome had a strong cancer cell inhibitory, and presented a dose-dependent inhibitory effect on migration. Further mechanistic studies showed that BDMC TSL combined with mild local hyperthermia could significantly upregulate B cell lymphoma 2 associated X protein levels and decrease B cell lymphoma 2 protein levels, thereby inducing cell apoptosis. The BDMC TSL that was fabricated via microfluidic device were decomposed under mild local hyperthermia, which could beneficially enhance the anti-tumor effect of raw insoluble materials and promote translation of liposome.

A simple microfluidic redox cycling-based device for high-sensitive detection of dopamine released from PC12 cells

Here, ITO electrodes modified with Au nanoparticles (AuNPs) were used to fabricate a microfluidic redox cycling-based chip device (AuNPs-MRECD) for highly sensitive and selective electrochemical detection of dopamine (DA). Briefly, ITO electrodes, each with a ∼ 3.2 × 3.2 mm2 working area, were fabricated using photolithography and dry etching processes. Afterward, the electrodes were modified with Au nanoparticles (AuNPs) electrochemically and used in the assembly of AuNPs-MRECD, in which case one AuNPs-ITO was mounted on top of another using a PET film spacer, which also defined the microfluidic channel of the device. According to the results, AuNPs-MRECD exhibited an excellent redox cycling efficiency with an amplification factor (Af) of 4.22 and a collection efficiency (Ce) of 93.7 %. Next, AuNPs-MRECD was tested for sensitive and selective detection of DA; where the device displayed an LOD of 27.9 nM over a linear detection range of 50 to 1000 nM based on reduction current. Finally, the device was successfully applied to the detection of DA released from PC12 cells, suggesting that the device is a promising tool for evaluating dopaminergic cells and the effects of dopaminergic drugs.

A direct liquid sampling interface for photoelectron photoion coincidence spectroscopy.

We introduce an effective and flexible high vacuum interface to probe the liquid phase with photoelectron photoion coincidence (liq-PEPICO) spectroscopy at the vacuum ultraviolet (VUV) beamline of the Swiss Light Source. The interface comprises a high-temperature sheath gas-driven vaporizer, which initially produces aerosols. The particles evaporate and form a molecular beam, which is skimmed and ionized by VUV radiation. The molecular beam is characterized using ion velocity map imaging, and the vaporization parameters of the liq-PEPICO source have been optimized to improve the detection sensitivity. Time-of-flight mass spectra and photoion mass-selected threshold photoelectron spectra (ms-TPES) were recorded for an ethanolic solution of 4-propylguaiacol, vanillin, and 4-hydroxybenzaldehyde (1 g/l of each). The ground state ms-TPES band of vanillin reproduces the reference, room-temperature spectrum well. The ms-TPES for 4-propylguaiacol and 4-hydroxybenzaldehyde are reported for the first time. Vertical ionization energies obtained by equation-of-motion calculations reproduce the photoelectron spectral features. We also investigated the aldol condensation dynamics of benzaldehyde with acetone using liq-PEPICO. Our direct sampling approach, thus, enables probing reactions at ambient pressure during classical synthesis procedures and microfluidic chip devices.

Design of a multilayer lung chip with multigenerational alveolar ducts to investigate the inhaled particle deposition.

We present the development and application of a multilayer microfluidic lung chip designed to accurately replicate the human respiratory bronchi, providing an innovative platform for controlled particle deposition in the lung. By employing a quantitative control method of fluid velocity through the deformation of an elastic PDMS membrane, this platform mimics the passive breathing process in humans and allows for precise simulation of the respiration cycle. We utilized time-lapse photography of fluorescent particles in a water/glycerol solution to qualitatively observe fluid morphology in the channel, while a chip-aerosol exposure device combined with microscopy imaging was employed to visualise aerosol deposition. Both experimental and numerical simulation results showed that particle concentration decreased towards the distal generations of the lung, and that changes in breathing pattern significantly affected particle deposition trends. Furthermore, we found that increasing the residence time of particles in the channel facilitated deeper particle deposition, achievable by adjusting parameters such as breath-hold time, exhalation time, respiration cycle length, and tidal volume. The proposed microfluidic lung chip device has significant potential for future research in respiratory health and inhaled drug delivery, providing an efficient, cost-effective, and ethical alternative to traditional in vivo studies.

A new microfluidic-chip device followed by sensitive image analysis of smart phone for simultaneous determination of dyes with different acidic–basic properties

In this study, a new microfluidic-chip coupled with micro solid phase extraction (μ-SPE) and a RGB detection system was designed. The method was used for extraction and simultaneous determination of trace amounts of dyes with different acidic–basic properties. Erythrosine (Ery) and Crystal Violet (CV) were selected as acidic and basic model analytes, respectively. The first step of this method is based on the on-chip electromembrane extraction (CEME) of analytes from aqueous solution. The utilized microfluidic system is a single compartment that composed of three polymethyl metacrylate plates (with sandwiched structures) patterned with palm shaped helix channels. The device consisted one pair of platinum electrodes that were embedded in the acceptor phase channels in each side. The middle part was cut and used as the path of the sample. The extracted analytes by CEME were passed through the micro-packed column containing strong cation and anion exchanger sorbents respectively. Two adsorbents were separated by a polypropylene frit and sealed on each side by two polypropylene frites. Following dye adsorption on the sorbents, the colors that emerged were promptly evaluated using RGB colorimetry on a smartphone. Central composite design was used to analyze and optimize the effective parameters on extraction efficiency. The relative standard deviations (RSDs%) based on five replicate measurements were less than 7.8% for RGB and 8.6% for the spectrophotometry technique under ideal conditions. Image analysis using a smartphone yielded LOD values of 15.0 and 10.5 μg L−1 for Ery and CV, respectively. The CEME- μ-SPE -RGB approach produced findings that were equivalent to those obtained by spectrophotometry. Finally, the approach was used to accurately determine Ery and CV in water samples, yielding good relative recoveries (recovery ≥94.0).

Effect Assessment of Aurantio-Obtusin on Novel Human Renal Glomerular Endothelial Cells Model Using a Microfluidic Chip.

Cassiae semen is widely used as a raw material of health food. Anthraquinone compounds, the main components in cassiae semen, have been reported to show nephrotoxicity. Aurantio-obtusin (AO) is a major anthraquinone compound extracted from cassiae semen. This study investigates the effects of AO on the morphology and physiological function of human renal glomerular endothelial cells (HRGECs) on a microfluidic chip device for the first time. HRGECs were cultured on a microfluidic plate and exposed to a series of AO concentrations. Compared with traditional 96-well culture, HRGECs cultured on the microfluidic chip appeared to better mimic the glomerular microenvironment in vivo. AO induced different degrees of damage to cellular morphology and physiological function. The leakage of lactate dehydrogenase (LDH), as well as the secretion of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), transforming growth factor-β1 (TGF-β1), and monocyte chemoattractant protein 1 (MCP-1), increased in the AO treated groups. At the same time, cell viability and expression of ZO-1 in the AO treated groups decreased in a dose-dependent manner. The innovative device enables direct visualization and quantification to evaluate the cytotoxic effects of AO on HRGECs, and provides a useful visual in vitro model for studying health effect of health food.

Hydrophilic metal-organic frameworks integrated uricase for wearable detection of sweat uric acid

The chemistry of the metal-organic frameworks (MOFs) coating may affect the biological functionality of the encapsulated biomacromolecules in harsh environment. Enzymes encapsulated in hydrophilic MAF-7 can retain high activity in harsh environment. We conducted this study to prepare a non-invasive wearable uircase@MAF-7-based electrochemical sensor that can achieve accurate and sensitive detection of UA levels in sweat by integrating a flexible microfluidic chip and wireless electronic readout device. The flexible microfluidic chip enabled an easy and effective collection of sweat samples. MAF-7 protected enzyme activity by encapsulating uricase. The uricase@MAF-7-based electrochemical sensor enabled the highly sensitive detection of UA in the concentration range of 2 μM–70 μM with a detection limit of as low as 0.34 μM. Additionally, we evaluated the utility of the sensor for monitoring UA levels in real sweat samples by means of a high purine dietary challenge. This personalized wearable sweat sensing device has a potential to be used for monitoring disease-related metabolites in daily life.

Patient-derived pancreatic cancer-on-a-chip recapitulates the tumor microenvironment

The patient population suffering from pancreatic ductal adenocarcinoma (PDAC) presents, as a whole, with a high degree of molecular tumor heterogeneity. The heterogeneity of PDAC tumor composition has complicated treatment and stalled success in clinical trials. Current in vitro techniques insufficiently replicate the intricate stromal components of PDAC tumor microenvironments (TMEs) and fail to model a given tumor’s unique genetic phenotype. The development of patient-derived organoids (PDOs) has opened the door for improved personalized medicine since PDOs are derived directly from patient tumors, thus preserving the tumors’ unique behaviors and genetic phenotypes. This study developed a tumor-chip device engineered to mimic the PDAC TME by incorporating PDOs and stromal cells, specifically pancreatic stellate cells and macrophages. Establishing PDOs in a multicellular microfluidic chip device prolongs cellular function and longevity and successfully establishes a complex organotypic tumor environment that incorporates desmoplastic stroma and immune cells. When primary cancer cells in monoculture were subjected to stroma-depleting agents, there was no effect on cancer cell viability. However, targeting stroma in our tumor-chip model resulted in a significant increase in the chemotherapy effect on cancer cells, thus validating the use of this tumor-chip device for drug testing.

Long-Term Fluorescence Behavior of CdSe/ZnS Quantum Dots on Various Planar Chromatographic Stationary Phases.

Nanoparticles, particularly quantum dots (QDs), are commonly used for the sensitive detection of various objects. A number of target molecules may be determined using QDs sensing systems. Depending on their chemical nature, physicochemical properties, and spatial arrangement, QDs can selectively interact with given molecules of interest. This can be performed in complex systems, including microorganisms or tissues. Efficient fluorescence enables low exposure of QDs and high sensitivity for detection. One disadvantage of quantum dots fluorophores is fluorescence decay. However, for given applications, this property may be an advantage, e.g., for highly sensitive detection based on correlation images in the time domain. This experimental work deals with the measurement of fluorescence decay of Lumidot TMCdSe/ZnS (530 nm) quantum dots. These nanoparticles were transferred to the surface of various planar chromatographic stationary phases. Fluorescence of formed spots was recorded at room temperature over a long period of time, namely 15.7824 × 105 min (three years). The resulting signal profiles in the time domain were analyzed using classical approach (luminescence model comparison involving different mathematical models).Moreover, fluorescence behavior on different TLC/HPTLC supports was investigated using multivariate statistics (principal component analysis, PCA). Eight planar chromatographic stationary phases were investigated, including cellulose, octadecylsilane, polyamide, silica gel and aluminium oxide in different forms (TLC and HPTLC types). The presented research revealed significantly different and non-linear long-term QDs behavior on these solids. Two different fluorescence signal trajectories were recorded, including typical signal decay after QDs application to the plates and long-term intensity increase. This was particularly visible for given planar chromatographic adsorbents, e.g., cellulose or octadecylsilane. To the author’s knowledge, these findings were not reported before using the stationary chromatographic phases, and enable the design of future experiments toward sensing of low molecular mass chemicals using, e.g., advanced quantification approaches. This may include signal processing computations based on correlation images in the time domain. Additionally, the reported preliminary data indicates that the investigated nanoparticles can be applied as efficient and selective fluorophores. This was demonstrated on micro-TLC plates where separated bioactive organic substances quenching from cyanobacteria extracts were sensitively detected. The described detection protocol can be directly applied for different planar chromatographic systems, including paper-based microfluidic devices, planar electrophoresis and/or miniaturized microfluidic chip devices.