Nanofluidic Technology Research Articles

Design of Magnetic Fluid Sensor Using Elliptically Hole Assisted Photonic Crystal Fiber (PCF)

The magnetic field sensor based on Photonic Crystal Fiber (PCF) is proposed by tuning the structure and magnetic fluid which is injected into the core. The sensitivity and resolution response of the magnetic field sensor under different magnetic field strength has been calculated for the magnetic field strength range from 100 Oe to 160 Oe. The investigated result shows the highest sensitivity response of 5000 pm/Oe and resolution of 11.33 Oe. The proposed structure has a vital role on nanofluidic technology. Because of the tenability of external magnetic field strength, high sensitivity and resolution the structure gives an awaited technology for the nanofluidics research.

Exploring Anomalous Fluid Behavior at the Nanoscale: Direct Visualization and Quantification via Nanofluidic Devices.

Nanofluidics is the study of fluids under nanoscale confinement, where small-scale effects dictate fluid physics and continuum assumptions are no longer fully valid. At this scale, because of large surface-area-to-volume ratios, the fluid interaction with boundaries becomes more pronounced, and both short-range steric/hydration forces and long-range van der Waals forces and electrostatic forces dictate fluid behavior. These forces lead to a spectrum of anomalous transport and thermodynamic phenomena such as ultrafast water flow, enhanced ion transport, extreme phase transition temperatures, and slow biomolecule diffusion, which have been the subject of extensive computational studies. Experimental quantification of these phenomena was also enabled by the advent of nanofluidic technology, which has transformed challenging nanoscale fluid measurements into facile optical and electrical recordings. Our groups' focus is to investigate nanoscale (2 to 103 nm) fluid behaviors in the context of fluid mechanics and thermodynamics through the development of novel nanofluidic tools, to examine the applicability of classical equations at the nanoscale, to identify the source of deviations, and to explore new physics emerging at this scale. In this Account, we summarize our recent findings regarding liquid transport, vaporization, and condensation of nanoscale-confined liquids. Our study of nanoscale water transport identified an additional resistance in hydrophilic nanochannels, attributed to the reduced cross-sectional area caused by the formation of an immobile hydration layer on the surfaces. In contrast, a reduction in flow resistance was discovered in graphene-coated hydrophobic nanochannels, due to water slippage on the graphene surface. In the context of vaporization, the kinetic-limited evaporation flux was measured and found to exceed the classical theoretical prediction by an order of magnitude in hydrophilic nanochannels/nanopores as a result of the thin film evaporation outside of the apertures. This factor was eliminated by modifying the hydrophobicity of the aperture's exterior surface, enabling the identification of the true kinetic limits inside nanoconfinements and a crucial confinement-dependent evaporation coefficient. The transport-limited evaporation dynamics was also quantified, where experimental results confirmed the parallel diffusion-convection resistance model in both single nanoconduits and nanoporous systems at high accuracy. Furthermore, we have extended our studies to different aspects of condensation in nanoscale-confined spaces. The initiation of condensation for a single-component hydrocarbon was observed to follow the Kelvin equation, whereas for hydrocarbon mixtures it deviated from classical theory because of surface-selective adsorption, which has been corroborated by simulations. Moreover, the condensation dynamics deviates from the bulk and is governed by either vapor transport or liquid transport depending on the confinement scale. Overall, by using novel nanofluidic devices and measurement strategies, our work explores and further verifies the applicability of classical fluid mechanics and thermodynamic equations such as the Navier-Stokes, Kelvin, and Hertz-Knudsen equations at the nanoscale. The results not only deepen our understanding of the fundamental physical phenomena of nanoscale fluids but also have important implications for various industrial applications such as water desalination, oil extraction/recovery, and thermal management. Looking forward, we see tremendous opportunities for nanofluidic devices in probing and quantifying nanoscale fluid thermophysical properties and more broadly enabling nanoscale chemistry and materials science.

Multiscale modelling of ceramic nanoparticle interactions and their influence on the thermal conductivity of nanofluids

There is currently a lack of a reliable theory capable of making accurate predictions of the thermal enhancement in nanofluids (with relatively low solid volume fractions). The work described therefore assesses the thermal conductivity of nanoparticle suspensions in fluids using a Lagrangian particle tracking-based computational modelling technique. A 3D, multiphase fluid-solid model is developed which predicts the motion of suspended nanoparticles. The nanofluid is predicted using an Eulerian-Lagrangian hybrid approach with a constant timestep. This technique takes various multiscale forces into consideration in the calculations, whose characteristic scales are quite different, providing for the first time an analysis of all factors affecting the stability and thermal conductivity of nanofluids. The system considered consists of 71 nm diameter Al2O3 ceramic nanoparticles suspended in water, with homogeneous temperature distributions ranging from 25 °C to 85 °C, at various volume fractions between 1% and 5%. The results of the simulations demonstrate the effectiveness of the presented technique, with predictions elucidating the role of Brownian motion, fluid viscous drag, inter-particle collisions and DLVO attraction and repulsion forces on nanofluid stability. Results indicate that aggregated nanoparticles formed in the suspensions, at various particle concentrations, play an important role in the thermal behaviour of the nanofluids. Predictions are in agreement with theoretical and experimental results obtained in related studies. The thermal characteristics of nanofluids are also considered as a function of temperature, system chemistry and time (measured from an initially homogeneously dispersed state). The proven enhancement in the conductivity of fluids affected by the addition of nanoparticles has great potential to assist the development of commercial nanofluid technology aimed at energy efficient and sustainable processes.

Heat transfer enhancement in single circular impingement jet by CuO-water nanofluid

A solo passive heat transfer enhancement technique represented by nanoparticle additives was embraced in this study due to the nanofluid technology potentials. A single circular jet (3 mm diameter) was used at Reynold number range of (1000–8000) with nozzle-to-jet Distance (Z) varied from 40 to 70 mm. Validation was conducted prior to commence the experimental tests and an accepted deviations were detected. The obtained outcomes showed the potential of CuO-water nanofluid to improve the heat transfer remarkably. Such enhancement increase as both Reynold number and volume fraction increase. Moreover, the Nozzle-to-target plate distance has the dominant effect over the volume fraction effect. Where the heat transfer decreases as the nozzle-to-target plate (Z) increase even if the volume fraction increase. Eventually, the maximum enhancement in Nusselt number was 2.9% and minimum enhancement was about 0.87%.

Single Cell Proteomics by Data-Independent Acquisition To Study Embryonic Asymmetry in Xenopus laevis.

Techniques that allow single cell analysis are gaining widespread attention, and most of these studies utilize genomics-based approaches. While nanofluidic technologies have enabled mass spectrometric analysis of single cells, these measurements have been limited to metabolomics and lipidomic studies. Single cell proteomics has the potential to improve our understanding of intercellular heterogeneity. However, this approach has faced challenges including limited sample availability, as well as a requirement of highly sensitive methods for sample collection, cleanup, and detection. We present a technique to overcome these limitations by combining a micropipette (pulled glass capillary) based sample collection strategy with offline sample preparation and nanoLC-MS/MS to analyze proteins through a bottom-up proteomic strategy. This study explores two types of proteomics data acquisition strategies namely data-dependent (DDA) and data-independent acquisition (DIA). Results from the study indicate DIA to be more sensitive enabling analysis of >1600 proteins from ∼130 μm Xenopus laevis embryonic cells containing <6 nL of cytoplasm. The method was found to be robust in obtaining reproducible protein quantifications from single cells spanning the 1-128-cell stages of development. Furthermore, we used micropipette sampling to study intercellular heterogeneity within cells in a single embryo and investigated embryonic asymmetry along both animal-vegetal and dorsal-ventral axes during early stages of development. Investigation of the animal-vegetal axis led to discovery of various asymmetrically distributed proteins along the animal-vegetal axis. We have further compared the hits found from our proteomic data sets with other studies and validated a few hits using an orthogonal imaging technique. This study forms the first report of vegetal enrichment of the germ plasm associated protein DDX4/VASA in Xenopus embyos. Overall, the method and data presented here holds promise to enable important leads in developmental biology.

Novel Nanofluidic IgE Assay versus a Reference Method: A Real-World Comparison

Background: Clinically meaningful specific IgE determination is an important step in the diagnosis of allergic diseases. While patient’s history and skin prick tests are available during the medical visit, most IgE immunoassays require hours to several days to be available. Recent developments in the field of nanofluidic technology open new horizons for point-of-care management of this unmet medical need. Objective: This study aimed to compare IgE diagnostic agreement between a nanofluidic assay (abioSCOPE®) and a laboratory reference method (Phadia Laboratory System®) in a real-world clinical setting. Methods: Sera from 105 patients whose routine allergy diagnostic workup required a blood sampling were used to compare the novel nanofluidic IgE assay to a reference method in a blind manner for a panel of five respiratory allergens. To assess the agreement between methods, patient records were reviewed by four independent experts to establish the final diagnosis. Experts were blinded to the IgE serological method used, but had access to patient history, skin prick tests, and blood test results. Results: Analytic agreement between the two methods was 81% for the tested panel of allergens (ranging from 77 to 89%). The overall agreement in clinical diagnosis decision taken by the expert panel was 94.6% with the nanofluidic IgE assay when compared to the reference method. Conclusion: The nanofluidic IgE assay, as determined through an evaluation based on clinical history, skin prick tests, and IgE measurement, is a valuable tool for allergy experts to identify patients’ sensitization patterns at the point of care, and for routine IgE diagnostic workup.

Interfacial properties of water/heavy water layer encapsulate in bilayer graphene nanochannel and nanocapacitor

Water through nanochannels of graphene (G) exposes the capillary pressure, calling fundamental understanding and predictive design of water within G nanochannels. Nanoconfinement induces switching behaviors at an atomic level, altering electronic and geometric structures. Herein, we study the single-layer water (SLW) and double-layer water (DLW) on monolayer G and encap-sulated in G layers and explore their diverse interfacial properties using a number of high level first principles calculations. By correlating the stability of adsorption, and interfacial properties such as intermediate pressure, charge transfer, structural deformation, one can decode various synergies in interaction properties of water on G nanocapillars. The external electric field (Eext) enhances polarization of system. More especially, changing the strength of Eext can effectively modulate the bandgap of monolayer G and bilayer graphene (BLG), and correspondingly causes a semimetal-semiconductor transition, i.e. Eg = 0.8 and 0.9 eV respectively. We also provide a comparison of phonon vibrational modes of water and heavy water (D2O) encapsulated within BLG, capturing their mobility as a key factor of separation mechanism. Moreover, we propose a nanocapacitor array of graphene-water-graphene composite, which electrodes has been separated by a water layer as a dielectric film. Nanometre-scale G capillaries open up a pathway to fabricate atomically channels walls for nanofluidic technology and nanocapacitor as a key device in integrated circuits (ICs).

Significance of alumina in nanofluid technology

Nanotechnology has emerged to be an essential aspect of science and technology. The growth of this field has been enormous specifically in the development of nanomaterials. Till date, numerous nanomaterials have been developed and designed to suit various applications from mechanical to biomedical. Among the developed nanomaterial, alumina (Al) has been subject of interest due to its notable chemical and physical properties. Specifically, in thermal properties, Al has been shown to have superior thermal conductivity, convective heat transfer coefficient and heat transfer coefficient properties. As such, Al has been utilized in different forms in various fields of applications and verified for its importance, significance and efficiency. Though it had shown outstanding results in the field engineering and sciences, their effect towards the environment and human health is yet to be explored extensively. The present paper aims to review the significance of Al nanoparticle addition in mono- and hybrid nanofluids. Also, this paper intends to provide the reader with an overview of the works that have been carried out using Al nanoparticles and their findings.

Experimental study on the effect of SiO2 nanoparticle dispersion on the thermophysical properties of binary nitrate molten salt

Molten salts, good heat transfer and thermal storage media, show potential for various applications, particularly solar thermal power. Nanofluid technology has been applied to molten salts to improve specific heat. In this study, molten salt nanofluids with a base solution of binary molten salt and SiO2 nanoparticles were prepared through high-temperature melting. The specific heat of the molten salt nanofluids was examined with different diameters and mass fractions of nanoparticles, and their optimal diameter and mass fraction were determined. The thermophysical properties of the optimized molten salt nanofluids were experimentally tested and compared with those of pure molten salt. Results reveal that the specific heat of the molten salt nanofluids is higher than that of the pure molten salt. The optimal mass fraction and size of SiO2 nanoparticles at the improved specific heat of the molten salt nanofluids are 1% and 20 nm, respectively. The optimal specific heat of the molten salt nanofluids is 17.8% more than that of the pure molten salt. The density of the optimized molten salt nanofluids is similar to that of the pure molten salt, and the average thermal conductivity is 20.2% more than that of the pure molten salt.

Calculated Terahertz Spectra of Glycine Oligopeptide Solutions Confined in Carbon Nanotubes.

To reduce the intense terahertz (THz) wave absorption of water and increase the signal-to-noise ratio, the THz spectroscopy detection of biomolecules usually operates using the nanofluidic channel technologies in practice. The effects of confinement due to the existence of nanofluidic channels on the conformation and dynamics of biomolecules are well known. However, studies of confinement effects on the THz spectra of biomolecules are still not clear. In this work, extensive all-atom molecular dynamics simulations are performed to investigate the THz spectra of the glycine oligopeptide solutions in free and confined environments. THz spectra of the oligopeptide solutions confined in carbon nanotubes (CNTs) with different radii are calculated and compared. Results indicate that with the increase of the degree of confinement (the reverse of the radius of CNT), the THz absorption coefficient decreases monotonically. By analyzing the diffusion coefficient and dielectric relaxation dynamics, the hydrogen bond life, and the vibration density of the state of the water molecules in free solution and in CNTs, we conclude that the confinement effects on the THz spectra of biomolecule solutions are mainly to slow down the dynamics of water molecules and hence to reduce the THz absorption of the whole solution in confined environments.

Micro-/Nanofluidics for Liquid-Mediated Patterning of Hybrid-Scale Material Structures.

Various materials are fabricated to form specific structures/patterns at the micro-/nanoscale, which exhibit additional functions and performance. Recent liquid-mediated fabrication methods utilizing bottom-up approaches benefit from micro-/nanofluidic technologies that provide a high controllability for manipulating fluids containing various solutes, suspensions, and building blocks at the microscale and/or nanoscale. Here, the state-of-the-art micro-/nanofluidic approaches are discussed, which facilitate the liquid-mediated patterning of various hybrid-scale material structures, thereby showing many additional advantages in cost, labor, resolution, and throughput. Such systems are categorized here according to three representative forms defined by the degree of the free-fluid-fluid interface: free, semiconfined, and fully confined forms. The micro-/nanofluidic methods for each form are discussed, followed by recent examples of their applications. To close, the remaining issues and potential applications are summarized.

Про гіперболічність і властивості розв’язків континуальних моделей агрегації та седиментації мікро наночастинок у концентрованих суспензіях

In continual mechanics sedimentation of aggregating particles in concentrated suspensions are determined by the mass and momentum conservation laws for each component of the suspension. The resulting quasilinear system of differential equations governing the flow could be hyperbolic, strongly strictly or weakly hyperbolic depending on the model accepted. The type and Eigenvalues of the matrix influence the characteristics of the pattern formation during the sedimentation that is essential for the model application in modern medical, microbiological and nanofluidic technologies. In this paper the hyperbolicity of the three-phase model of aggregation and sedimentation of micro/nanoparticles is studied.

Experimental study on thermophysical properties of molten salt nanofluids prepared by high-temperature melting

Heat storage is a key technology in solar thermal power, helps solar thermal power eliminate the instability in energy supply for the grid, and provides continuous and stable high-quality electrical energy to improve power system efficiency and extend system life. Molten salt is an important material for heat storage and heat transfer in solar thermal power. In recent years, nanofluid technology has been applied to investigate heat storage and transfer materials, such as molten salt, to improve heat capacity. However, the nanofluid technology is hampered by the easy agglomeration of nanoparticles in molten salts, and this phenomenon degrades the performance of the molten salt nanofluids. To reduce or prevent agglomeration, a two-step method with high-temperature melting in preparing molten salt nanofluids is developed recently. Molten salt nanofluids obtained by high-temperature melting show good stability and long time to agglomerate. This paper presented the study on the thermophysical properties of molten salt nanofluids prepared by high-temperature melting method. The molten salt nanofluids possessed low-melting point salt as base liquid and SiO2 with a diameter of 20 nm as nanoparticles. The specific heat of this type of molten salt nanofluid was tested, and the optimum concentration of nanoparticles was determined. Results showed that the specific heat capacities of the molten salt nanofluid samples with different mass fractions of nanoparticles were higher than those of pure molten salt. The average specific heat of molten salt nanofluid with a mass fraction of 0.5% was the highest at 1.950 J/(g K), which was 24.5% more than that of pure molten salt. The thermophysical properties of molten salt nanofluids with a mass fraction of 0.5% and prepared by high-temperature melting were experimentally tested and compared with those of pure molten salt. These properties included melting point, primary crystallization point, thermal conductivity, viscosity, latent heat, and density. The molten salt nanofluids showed good performance for heat storage and transfer.

Nanofluidic terahertz metasensor for sensing in aqueous environment

The terahertz spectral region has received tremendous attention for label free chemical and biological sensing, due to the presence of molecular fingerprints, low energy characteristics, and remote sensing capabilities. However, a major hindrance for the realization of a high performance terahertz bio-chemical sensor comes from the large absorption of terahertz waves by aqueous solution. Here, we overcome this limitation by confining the analyte-aqueous solution in a nanovolumetric fluidic chamber, integrated on metamaterial resonant cavities. The metamaterial resonators confine electromagnetic fields in extremely subwavelength space and hence allow for the enhanced interaction between the nanovolumetric analyte-aqueous solution and terahertz waves, while minimizing the absorption loss. We compare the sensing performance of split ring resonator and Fano resonator systems as metamaterial resonators. As a demonstration of chemical sensing, three alcoholic solutions with different concentrations were measured. Selective adenosine triphosphate (ATP) sensing capability was examined through ATP aptamer functionalization on gold metamaterials, where a decrease in the transmittance value was observed as the ATP concentration increased. The proposed sensing approach has the potential to be an effective tool for molecular analysis through exploiting the advantages offered by low energy terahertz, subwavelength metamaterial resonators and nanofluidic technologies.

Structure and transport of confined liquid in nanochannels

In recent years, the mass transport through nanochannels has received widespread attention from the academic and engineering communities, as well as industry, not only due to its cutting-edge significance in physical mechanics of surfaces and interfaces, but also because of its crucial application prospects in the fields of energy, environment, and health. At the nanometer scale, the interface effect and intermolecular interactions are prominent. The free movement of liquid molecules is confined, and its structure also exhibits layering, ordering, and other characteristics. Due to this fact, the transport of confined liquid yields distinguishable results from those at the macroscale. Both the governing equations and boundary conditions for nanoflow are worth further investigation. The understanding on the structure and transport of confined liquid also plays an important role in the applications of microfluidic and nanofluidic technologies. As the length scale of nanodevices decreases continuously, the surface and interface effects become significant. The structure and dynamic behaviours of confined liquid are dramatically different from that of the bulk phase. At the nanoscale, several physical mechanisms are intercoupling; various intermolecular and surface forces compete with each other. There are many characteristic length scales which fall in the range from a few angstroms to several nanometers. This review article focuses on the structure and transport of confined liquids, and systematically reviews the recent research progress in this field. Starting from the ordered structures of the confined water, we discussed not only the layered structure perpendicular to the confining walls, but also various two dimensional ice phases parallel to the walls. Emphasis was placed on the hot topics of water transport and ion sieving through various kinds of nanochannels, especially for capillaries existing in graphene oxide membranes and nanocapillaries fabricated by van der Waals assembly using two-dimensional materials. The source of the complexity of the ordered structure and transport process of confined liquids was analyzed. We also discussed that slip boundary conditions and driving forces in modeling such process require extra attention and in-depth investigations. It was revealed that the mechanism of liquid flow through nanochannels is dominated by intermolecular forces. Although there are still many unknown questions to be further explored, we tried to point out the possible directions of the organic combination of theory, simulation and experimental research, as well as the interdisciplinary integration.

A concise review on the role of nanoparticles upon the productivity of solar desalination systems

In recent years, nanofluids have been widely used to improve the performance of various energy systems due to their favourable thermo-physical and optical characteristics. In particular, solar distillation, as an affordable and reliable technique to provide freshwater, has benefited from nanofluid technology. This article performs a review of the literature on the implementation of nanofluid technology in active and passive solar distillation systems. The progress made and the existing challenges are discussed, and some conclusions and suggestions are made for future research. The review indicates that the daily productivities of solar distillation systems enhance by using nanofluid and increasing the volume fraction of nanoparticles. However, long-term operational stability and life cycle assessment remain critical issues. These factors should be considered for future research in this field.

Electrokinetic ion transport in nanofluidics and membranes with applications in bioanalysis and beyond.

Electrokinetic transport of ions between electrolyte solutions and ion permselective solid media governs a variety of applications, such as molecular separation, biological detection, and bioelectronics. These applications rely on a unique class of materials and devices to interface the ionic and electronic systems. The devices built on ion permselective materials or micro-/nanofluidic channels are arranged to work with aqueous environments capable of either manipulating charged species through applied electric fields or transducing biological responses into electronic signals. In this review, we focus on recent advances in the application of electrokinetic ion transport using nanofluidic and membrane technologies. We start with an introduction into the theoretical basis of ion transport kinetics and their analogy to the charge transport in electronic systems. We continue with discussions of the materials and nanofabrication technologies developed to create ion permselective membranes and nanofluidic devices. Accomplishments from various applications are highlighted, including biosensing, molecular separation, energy conversion, and bio-electronic interfaces. We also briefly outline potential applications and challenges in this field.

Disclosing respiratory co-infections: a broad-range panel assay for avian respiratory pathogens on a nanofluidic PCR platform

ABSTRACT Respiratory syndromes (RS) are among the most significant pathological conditions in edible birds and are caused by complex coactions of pathogens and environmental factors. In poultry, low pathogenic avian influenza A viruses, metapneumoviruses, infectious bronchitis virus, infectious laryngotracheitis virus, Mycoplasma spp. Escherichia coli and/or Ornithobacterium rhinotracheale in turkeys are considered as key co-infectious agents of RS. Aspergillus sp., Pasteurella multocida, Avibacterium paragallinarum or Chlamydia psittaci may also be involved in respiratory outbreaks. An innovative quantitative PCR method, based on a nanofluidic technology, has the ability to screen up to 96 samples with 96 pathogen-specific PCR primers, at the same time, in one run of real-time quantitative PCR. This platform was used for the screening of avian respiratory pathogens: 15 respiratory agents, including viruses, bacteria and fungi potentially associated with respiratory infections of poultry, were targeted. Primers were designed and validated for SYBR green real-time quantitative PCR and subsequently validated on the Biomark high throughput PCR nanofluidic platform (Fluidigm©, San Francisco, CA, USA). As a clinical assessment, tracheal swabs were sampled from turkeys showing RS and submitted to this panel assay. Beside systematic detection of E. coli, avian metapneumovirus, Mycoplasma gallisepticum and Mycoplasma synoviae were frequently detected, with distinctive co-infection patterns between French and Moroccan flocks. This proof-of-concept study illustrates the potential of such panel assays for unveiling respiratory co-infection profiles in poultry.

Total Capture, Convection-Limited Nanofluidic Immunoassays Exhibiting Nanoconfinement Effects.

Understanding nanoconfinement phenomena is necessary to develop nanofluidic technology platforms. One example of nanoconfinement phenomena is shifts in reaction equilibria toward reaction products in nanoconfined systems, which have been predicted theoretically and observed experimentally in DNA hybridization. Here we demonstrate a convection-limited nanofluidic immunoassay that achieves total capture of a target analyte and an apparent shift in the antibody-antigen reaction equilibrium due to nanoconfinement. The system exhibits wavefronts of the target analyte that propagate along the length of the nanochannel at a velocity much slower than that of the carrier fluid. We apply an analytical model describing the propagation of these wavefronts to determine the density of capture antibody binding sites in the enclosed nanochannel for a known concentration of the target analyte. We then use this binding site density to estimate the concentration of solutions with 5× and 10× less analyte. Our analysis suggests that nanoconfinement results in a preference toward binding of the target analyte with the surface-grafted capture antibody, as evidenced by an apparent reduction in the equilibrium dissociation constant. Our findings motivate the advancement of new biomedical and chemical synthesis technologies by leveraging nanoconfinement effects, and demonstrate a useful platform for studying the effect of nanoconfinement on chemical systems.

Fast and accurate enzyme activity measurements using a chip-based microfluidic calorimeter

Recent developments in microfluidic and nanofluidic technologies have resulted in development of new chip-based microfluidic calorimeters with potential use in different fields. One application would be the accurate high-throughput measurement of enzyme activity. Calorimetry is a generic way to measure activity of enzymes, but unlike conventional calorimeters, chip-based calorimeters can be easily automated and implemented in high-throughput screening platforms. However, application of chip-based microfluidic calorimeters to measure enzyme activity has been limited due to problems associated with miniaturization such as incomplete mixing and a decrease in volumetric heat generated. To address these problems we introduced a calibration method and devised a convenient protocol for using a chip-based microfluidic calorimeter. Using the new calibration method, the progress curve of alkaline phosphatase, which has product inhibition for phosphate, measured by the calorimeter was the same as that recorded by UV-visible spectroscopy. Our results may enable use of current chip-based microfluidic calorimeters in a simple manner as a tool for high-throughput screening of enzyme activity with potential applications in drug discovery and enzyme engineering.