Transduction Techniques Research Articles

Imaging electrochemiluminescence layer to dissect concentration-dependent light intensity for accurate quantitative analysis

As one of most advanced transduction techniques, electrochemiluminescence (ECL), such as that generated by tris(2,2′-bipyridyl)ruthenium (Ru(bpy)32+), has been extensively used in chemical sensing and analysis, but the reaction mechanism has not been fully resolved. Aiming at gaining insightful mechanistic information on the coreactant system involving (Ru(bpy)32+) and tri-n-propylamine (TPrA), herein we investigate the variation of thickness of ECL layer (TEL) with the concentration ratio of (Ru(bpy)32+) to TPrA (cRu/cTPrA) by ECL microscopy. Using carbon fiber as the working electrode, TEL was observed to grow with the increase of cRu/cTPrA remarkably. In conjunction with finite element simulations, the extension of ECL layer was rationalized to be associated with the incremental contribution of so-called “catalytic route”. This route offers an additional channel of generating remote light emission in solution, apart from surface-confined emission produced by the “oxidative-reduction route”. Given the quantitative analysis of coreactant-type analytes is often based on the calibration curve, namely a graph generated by plotting the measured light intensity of a series of standard solutions against their concentrations, the contribution of “catalytic route” particularly at a low concentration of analyte (equivalent to a relatively large cRu/cTPrA) is favorable to the analytical sensitivity. Moreover, the presence and absence of this route will result in a nonlinear and linear calibration curve, respectively, for example in the detection of TPrA and pyruvate. The results highlight the microwire-based imaging approach can provide insightful mechanistic information and help unveil the concentration dependence of measured ECL intensity for precise quantitative analysis.

Recent Developments for the Detection of Escherichia Coli Biosensors Based on Nano-Objects—A Review

Advances in nanotechnology have made it possible in recent years to develop strategies for rapid and sensitive detection of pathogenic bacteria using new nanomaterials and the development of electronic nano-sensors. The detection of bacteria still faces problems such as long analysis time and complexity of the process. An alternative method is the use of biosensors, which combines a biological recognition mechanism with a physical transduction technique. Thus, a number of methods and manufacturing technologies have been developed in order to achieve performance in sensitivity, detection limit, label-free detection or real-time analysis. This review aims to focus on the state of the art of biosensors for the recognition elements of Escherichia coli in label-free biosensors with a particular focus on the beneficial use of nanomaterials and nano-objects for detection. Among the recent related biosensors based on nano-objects for <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E. coli</i> detection, the technologies and measurement techniques are detailed by comparing their performances detection in terms of concentration range and detection limit. Detection becomes more sensitive and more flexible using nanoparticles as markers, and real-time electrical detection methods are dominant in comparison with optical ones. The lowest detection limit can be achieved for sensors based on metal (gold or silver nanoparticles) with optical detection techniques in contrast with electrical detection methods using measurement conductance.

A fully integrated and handheld electrochemiluminescence device for detection of dopamine in bio-samples

Electrochemiluminescence (ECL) is a powerful electroanalytical transduction technique in biosensing and clinic immunodiagnostics, however its practical applications for point-of-care testing (POCT) are rather limited because of the requirements of large sized electrochemical workstation for electrical stimulation and photomultiplier tube for light detection. Herein we report a fully integrated and handheld ECL device consisting of a flexible printed circuit board based electrochemical module, a silicon photomultiplier and a Bluetooth enabled smartphone with an Android application interface. The device together with an electrochemical cell and light-tight box has a dimension of 17 cm × 9 cm × 9 cm, thus being suitable for on-site detection and POCT. To demonstrate the performance and efficiency of this device, we implemented the detection of dopamine (DA), using the indium tin oxide glass electrode coated with antifouling silica nanoporous membrane as the working electrode for improving the sensing stability and sensitivity. A fast response to DA with a wide linear range of 5 nM ∼ 20 μM and an ultralow detection limit of 3.5 nM were obtained with the handheld ECL device. These attractive features allow the device to satisfy the basic requirements for POCT of DA in complex bio-samples, including urine and rat brain homogenate. This work provides a novel strategy for ECL based POCT, showing the potential of broad utility in resource-limited settings where there is a lack of medical facilities.

Design of Dual Transduction-Based CMOS-MEMS Electronic Stethoscope

The stethoscope provides primary information about the heart and the lungs. It enables rough diagnosis of the functionalities of heart and lungs of the human body through the pick-up of emitted sound from within them. Acoustic determination of the functionality of the critical organs must have high accuracy to reduce mortality rate. Manual examination and diagnosis with reliance on sound have poor reliability due to the nature of high interference causing inaccuracy. Second order harmonics are significantly high due to such interferences resulting in distortion. There is a need for technical advancement for efficient and seamless pick up of the bio-sounds. Existing electronic stethoscope design is cumbersome and uneconomical. A novel dual transduction technique is proposed in this CMOS-MEMS electronic stethoscope design, which produce high SNR value and high sensitivity. This proposed electronic stethoscope includes two microsensors, viz. piezoresistors and the piezoelectric device that provides high accuracy. Dual transduction enables pick up off of two bands of frequency that emanates the function of the heart and the lungs with great precision.

Boron-Doped Diamond Electrode Outperforms the State-of-the-Art Electrochemiluminescence from Microbeads Immunoassay.

Electrochemiluminescence (ECL) is a powerful transduction technique where light emission from a molecular species is triggered by an electrochemical reaction. Application to biosensors has led to a wide range of electroanalytical methods with particular impact on clinical analysis for diagnostic and therapeutic monitoring. Therefore, the quest for increasing the sensitivity while maintaining reproducible and easy procedures has brought investigations and innovations in (i) electrode materials, (ii) luminophores, and (iii) reagents. Particularly, the ECL signal is strongly affected by the electrode material and its surface modification during the ECL experiments. Here, we exploit boron-doped diamond (BDD) as an electrode material in microbead-based ECL immunoassay to be compared with the approach used in commercial instrumentation. We conducted a careful characterization of ECL signals from a tris(2,2'-bipyridine)ruthenium(II) (Ru(bpy)32+)/tri-n-propylamine (TPrA) system, both homogeneous (i.e., free diffusing Ru(bpy)32+) and heterogeneous (i.e., Ru(bpy)32+ bound on microbeads). We investigated the methods to promote TPrA oxidation, which led to the enhancement of ECL intensity, and the results revealed that the BDD surface properties greatly affect the ECL emission, so it does the addition of neutral, cationic, or anionic surfactants. Our results from homogeneous and heterogeneous microbead-based ECL show opposite outcomes, which have practical consequences in ECL optimization. In conclusion, by using Ru(bpy)32+-labeled immunoglobulins bound on microbeads, the ECL resulted in an increase of 70% and a double signal-to-noise ratio compared to platinum electrodes, which are actually used in commercial instrumentation for clinical analysis. This research infers that microbead-based ECL immunoassays with a higher sensitivity can be realized by BDD.

Nanomaterials for IoT Sensing Platforms and Point-of-Care Applications in South Korea.

Herein, state-of-the-art research advances in South Korea regarding the development of chemical sensing materials and fully integrated Internet of Things (IoT) sensing platforms were comprehensively reviewed for verifying the applicability of such sensing systems in point-of-care testing (POCT). Various organic/inorganic nanomaterials were synthesized and characterized to understand their fundamental chemical sensing mechanisms upon exposure to target analytes. Moreover, the applicability of nanomaterials integrated with IoT-based signal transducers for the real-time and on-site analysis of chemical species was verified. In this review, we focused on the development of noble nanostructures and signal transduction techniques for use in IoT sensing platforms, and based on their applications, such systems were classified into gas sensors, ion sensors, and biosensors. A future perspective for the development of chemical sensors was discussed for application to next-generation POCT systems that facilitate rapid and multiplexed screening of various analytes.

Wearable electrochemical microneedle sensing platform for real-time continuous interstitial fluid monitoring of apomorphine: Toward Parkinson management

Parkinson’s disease (PD) is a progressive neurodegenerative disorder, impacting millions of people across the globe. For its management, pro-neurotransmitters or agonists are commonly being prescribed, which help to mitigate the symptoms. However, the progressiveness of PD and narrowing down of the drug therapeutic window eventually led to its ineffective management. Therefore, the requirement of continuous monitoring of administered drugs is of utmost need. In view of this, here, we demonstrate a microneedle-based wearable electrochemical sensor platform for the continuous monitoring of apomorphine (APO), a widely used therapeutic drug for Parkinson’s management. The APO sensor relies on a metallized carbon-paste packed hollow microneedle, operated using the square wave voltammetry (SWV) and chronoamperometry (CA) based transduction modes. Under the optimal conditions, the microneedle sensor offers sensitive detection of micromolar APO concentrations in artificial interstitial fluid (ISF) through the monitoring of the two oxidation peaks of the APO catechol and tertiary amine moieties (at 0.1 V and 0.7 V, respectively). The microneedle sensor exhibited a detection limit of 0.6 and 0.75 μM with the transduction techniques SWV and CA, respectively, and good operational stability as well as anti-biofouling protection in artificial-ISF medium. The specificity has been tested for the developed sensor in the presence of potential interfering molecules, where the developed sensor showed the selectivity towards APO. The attractive analytical performance demonstrated in the skin mimic environment makes the new wearable APO microneedle sensor a powerful candidate for continuous APO detection in PD management.

DNA-Based Nanoswitches: Insights into Electrochemiluminescence Signal Enhancement.

Electrochemiluminescence (ECL) is a powerful transduction technique that has rapidly gained importance as a powerful analytical technique. Since ECL is a surface-confined process, a comprehensive understanding of the generation of ECL signal at a nanometric distance from the electrode could lead to several highly promising applications. In this work, we explored the mechanism underlying ECL signal generation on the nanoscale using luminophore-reporter-modified DNA-based nanoswitches (i.e., molecular beacon) with different stem stabilities. ECL is generated according to the “oxidative-reduction” strategy using tri-n-propylamine (TPrA) as a coreactant and Ru(bpy)32+ as a luminophore. Our findings suggest that by tuning the stem stability of DNA nanoswitches we can activate different ECL mechanisms (direct and remote) and, under specific conditions, a “digital-like” association curve, i.e., with an extremely steep transition after the addition of increasing concentrations of DNA target, a large signal variation, and low preliminary analytical performance (LOD 22 nM for 1GC DNA-nanoswtich and 16 nM for 5GC DNA-nanoswitch). In particular, we were able to achieve higher signal gain (i.e., 10 times) with respect to the standard “signal-off” electrochemical readout. We demonstrated the copresence of two different ECL generation mechanisms on the nanoscale that open the way for the design of customized DNA devices for highly efficient dual-signal-output ratiometric-like ECL systems.

High-Efficiency Lentiviral Genetic Modification of Primary Human Natural Killer Cells

Natural killer (NK) cells have the unique capacity to lyse tumor cells without the need for antigen specific receptors. Modulation of NK cell cytokine, chemokine, and activating and inhibitory receptor expression using gene regimens represents an attractive strategy to further bolster NK cell anti-tumor activity for the purpose of NK cell immunotherapy. Current efforts in clinical-grade genetic modification of patient-derived cells, used in immunotherapy protocols, rely on stable transduction mediated by viral vectors. However, primary NK cells are notoriously difficult to transduce using viral vectors. Here we describe a lentiviral vector-based approach that results in an efficient, robust, and highly reproducible method of stable gene transfer into primary human peripheral blood-derived NK cells, which can subsequently be expanded ex vivo for adoptive infusion into humans. In vitro experiments established highly efficient transduction of ex vivo expanded NK cells could be achieved by activation of primary NK cells in vitro for 2-4 days in cytokine containing media followed by transduction of activated NK cells using LV vectors 2-3 days before integration into our existing ex vivo expansion protocol using irradiated EBV-LCL feeder cells. Unless NK cells were first activated in cytokine-containing media, LV transduction was unsuccessful. Cytokine activation in media containing IL-2 for 2-4 days was found to be sufficient to achieve high transduction efficiency, while additional supplementation of the media with IL-15 or IL-21 had negligible effects. NK cell transduction efficiency and viability with the use of RetroNectin® was uniformly superior to polycation-based transduction protocols. In experiments where NK cells were transduced with identical lentiviral constructs with 8 different promoter sequences driving expression of EGFP, PGK, EFS, and SV40 promoters consistently demonstrated the highest transduction efficiencies reproducibly in the range of 25-60%. Remarkably, when transduced NK cells were stimulated ex vivo using a clinical grade irradiated EBV-LCL feeder cell line, 100-1000 fold expansions of transduced NK cells could be achieved with sustained transgene expression over two weeks. Transduced and expanded primary NK cells remained highly cytotoxic against K562 tumor targets without developing functional deficiencies in degranulation, IFNγ, or TNFα production. These data establish a simple method to produce large numbers (>1011) of genetically modified clinical grade NK cells suitable for infusion. The protocol described herein overcomes previous difficulties described with common transduction techniques opening new avenues to investigate the impact of adoptive infusion of primary NK cells stably transduced to express a variety of different transgenes of interest. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Electronic Spiking Protein-Based COVID Sensors

Viruses are ultimate nanotechnology objects with cleverly designed capsid proteins to bind with cell membranes and exquisite DNA/RNA machinery to invade cells and replicate themselves using cells' machinery. Here I will discuss an electronic virus sensor that uses aptamers designed to bind with the COVID-19 spiking proteins S1 and S2 to capture the virus inside a quantum mechanical tunneling gap device. The current through the gap, that is sized to match the COVID-19 diameter of 125 nm, is monitored to detect the presence of the virus. The gap impedance also changes and can be monitored. The sensor works with small amount of saliva deposited over its active area. Saliva is a complex fluid composed of 99.49% water, enzymes, human cells, bacteria, opiorphin, haptocorrin, alfa-amylase, antibacterial compounds, mucus, and electrolytes (sodium, potassium, calcium, etc.). It also contains 60 nm -100 nm exosomes. Except for human cells, bacteria and exosomes, all other fresh saliva components have small molecules (mucus can produce large particles in old saliva). Exosomes and any other nanoparticles inside the fresh saliva can potentially produce false positive results. False negative results, on the other hand, are produced when the viruses in the saliva do not bind with the sensor aptamers. Filtering is used to exclude large (>200 nm) particles. Ultrasonication as well as electric field biasing/excitation techniques are used to ensure virus-aptamer encounter and binding. Exosomes' sizes make them difficult to exclude using filtering. Currently I am developing a technique based on dielectrophoretic responses of exosomes and viruses to preferentially trap the COVID-19 and repel the exosomes. The sensor's limit of detection is close to a single virus owing to its transduction technique of quantum mechanical tunneling current. I will discuss COVID-19 electronic sensor performance and its performance along with its fabrication and applications in this talk.

Potential of Impedance Spectroscopy Towards Quantified Analysis of Gas Sensors: A Tutorial

Transduction of the gas sensor devices through Impedance Spectroscopy (IS) provides non-conventional route to derive quantified model of equivalent circuit and to address resonant frequency tuned selectivity aspect. The quantification of the equivalent circuit elements possibly enhances the scientific understandings of sensing performance in computational scheme. Simultaneously, resonant frequency tuned selectivity approach is another possible outcome of the IS, applied to the gas sensors. These methodologies, prove the potentiality of the IS highlighting the theoretical as well as practical aspects of gas sensor devices. The present scope focuses on the step-by-step approach of flexible adoption in measuring techniques of the IS from its liquid phase measurement to gas phase one. The comparative analysis of quantitative equivalent circuit in different gas ambient is fruitful to presume the experimental details as well as the underlying physical phenomena. The input signal frequency also paved the path for the resonant frequency tuned selectivity improvement for the gas sensor devices. Importance of the IS, as transduction technique, is also discussed with physical, theoretical and computational insights. This review also dealt with corresponding constraints of IS in gas sensors by thorough inspection of different bottlenecks reported in literatures. The present review also has a focus to instigate further research to mitigate such constraints and to further improve the potentiality of the IS in gas sensor field.

A modified parachute assay for assessment of gap junction intercellular communication in placental trophoblast cells

Gap junction intercellular communication (GJIC) is a necessary process for placental development. GJIC can be assessed with a parachute assay, where fluorescent dye-loaded donor cells are ‘parachuted’ onto acceptor cells and dye diffuses to adjacent cells with active GJIC. During co-culture, donor cells can attach, but the assay does not allow their distinction from acceptor cells, which presents as a major limitation. We have developed a modified parachute assay that permits distinction between donor and acceptor cells, using the extravillous trophoblast cell line HTR-8/SVneo and a lentiviral transduction technique. Using PKA activator CW008 as a positive control and 12-o-tetradecanoylphorbol-13-acetate as a negative control, this modified parachute assay reliably detects both enhanced and attenuated GJIC. Importantly, the ease and accuracy of quantification over currently available methods makes this modified assay optimal for automation and represents a useful tool for in vitro placental toxicological testing.

Recent Advancements in Development of Wearable Gas Sensors

AbstractIn the era of the Internet of Things, wearable technologies are expected to become an indispensable part of daily life. In recent times, highly sensitive, flexible, and stretchable electronic gas sensors are gaining tremendous interest due to their applicability in wearable electronics applications. The construction of wearable gas sensors are reviewed for real‐time, highly sensitive, and selective detection of hazardous gases at room temperature (RT) that can be laminated onto a human body or integrated with body‐worn textile or other consumer products, utilizing carbon nanomaterials, conductive polymers, 2D nanostructured materials, and their composites. Sensing materials, transduction techniques, and substrates for high‐performance wearable gas sensing are discussed in detail. The critical challenges for future development of wearable gas sensors are presented. Wearable gas sensors are believed to have great potential in environmental monitoring, healthcare, public safety, security, as well as food quality monitoring.

Point-of-care detection of tuberculosis using magnetoresistive biosensing chip

In this paper, a highly sensitive and specific technique based on the principle of giant magnetoresistance (GMR) has been proposed for the early stage Tuberculosis (TB) diagnostics. This GMR biosensing assay employs monoclonal antibodies against M. tuberculosis specific ESAT-6 antigen with the use of magnetic nanoparticles (MNPs) as labels. MNPs bind to the GMR sensor in presence of ESAT-6 and the binding is proportional to the ESAT-6 protein concentration leading to the change in overall resistance of GMR sensor. GMR biosensor simulation showed that ESAT-6 concentration can be detected in the range of pg/mL in comparison to the other transduction techniques available for ESAT-6 detection and further, the signal strength increased with the increase in the concentration. This work has shown that the GMR biosensing strategy is pertinent for the TB detection at the primitive phases when compared with other magnetic techniques used for TB diagnostics.

Mathematical modeling of different diaphragm geometries in MEMS pressure sensor

Abstract Micro pressure sensors generally employ diaphragm as the sensing element which converts the applied pressure into appropriate displacement. The displacement can be further used for sensing the actual physical phenomena viz., pressure or force with different transduction techniques. The transduction mechanism could be piezoresistive, capacitive, piezoelectric or resonant, etc. It is utmost essential to comprehend the behaviour of the structural element before its design with respect to transduction technique. The parameter optimization of diaphragm is the prime challenge in order to achieve the unsurpassed performance of the device. In this work, three of the diaphragm geometries namely a square diaphragm, a rectangular diaphragm and a circular diaphragm are considered for structural analysis. The displacement and stress analysis of the structures are carried out and investigated with the help of finite element-based simulation. The performed analysis will be useful in the selection of pressure sensor which provides optimized sensor geometry for required sensitivity, linearity, output range and area.

Functionalized SERS substrate based on silicon nanowires for rapid detection of prostate specific antigen

Abstract Owing to its high sensitivity, surface-enhanced Raman spectroscopy (SERS) is widely used in biosensing as an efficient optical transduction technique. In this work, we report the elaboration of a novel SERS-powered aptasensing substrate for the ultra-sensitive and selective detection of prostate specific antigen (PSA). The transducing SERS substrate is formed by vertically aligned silicon nanowires (SiNWs) decorated with silver nanoparticules (AgNPs). The silver nanoparticles have two purposes : a) aptamer immobilization via thiol chemistry and b) Raman signal enhancement. The presence of PSA induces the appearance of amide bond vibration modes only if the aptamer is present on the surface of SiNWs. The platform is highly sensitive, selective and specific to PSA in a wide range of concentrations from 0.1 to 20 μg.L−1 with a detection limit of 0.1 μg.L−1, which encompasses the blood serum range of healthy subjects and ill patients. This optical biosensor shows a great stability and it is successfully validated in human blood serum samples showing very good results.

Microtube Electrodes for Imaging the Electrochemiluminescence Layer and Deciphering the Reaction Mechanism.

Electrochemiluminescence (ECL) is a powerful transduction technique in biosensing and diagnostics, while mechanistic studies are still scarce. Herein we report the combined use of microtube electrode (MTE) and microscopy to measure the thickness of ECL layer (TEL) to decipher reaction mechanisms. For the classical system involving tris(2,2'-bipyridyl)ruthenium and tri-n-propylamine, the ECL pattern generated at the MTE tends to change from ring to spot upon increasing the luminophore concentration, with the TEL varying from ca. 3.1 μm to >4.5 μm. This variation is rationalized to arise from the contribution of the so-called catalytic route. While using 2-(dibutylamino)ethanol as the co-reactant, the ECL pattern remains ring-shaped and independent on the luminophore concentration. The TEL in this case is ca. 2.1 μm, implying that ECL generation is always surface-confined. MTEs can thus act as optical rulers for measuring the TEL and providing insightful mechanistic information.

Microtube Electrodes for Imaging the Electrochemiluminescence Layer and Deciphering the Reaction Mechanism

AbstractElectrochemiluminescence (ECL) is a powerful transduction technique in biosensing and diagnostics, while mechanistic studies are still scarce. Herein we report the combined use of microtube electrode (MTE) and microscopy to measure the thickness of ECL layer (TEL) to decipher reaction mechanisms. For the classical system involving tris(2,2′‐bipyridyl)ruthenium and tri‐n‐propylamine, the ECL pattern generated at the MTE tends to change from ring to spot upon increasing the luminophore concentration, with the TEL varying from ca. 3.1 μm to &gt;4.5 μm. This variation is rationalized to arise from the contribution of the so‐called catalytic route. While using 2‐(dibutylamino)ethanol as the co‐reactant, the ECL pattern remains ring‐shaped and independent on the luminophore concentration. The TEL in this case is ca. 2.1 μm, implying that ECL generation is always surface‐confined. MTEs can thus act as optical rulers for measuring the TEL and providing insightful mechanistic information.

Polymer/Ceramic MEMS: A Nanomechanical Sensor Platform With Low Temperature High Gauge Factor ITO for Electromechanical Transduction

MEMS biochemical sensors based on nanomechanical cantilevers (NMC) translate bio/chemical interactions into nanomechanical motion that can be detected by various transduction techniques. Polymer Nanomechanical Sensors have proven to be better candidates than the conventional silicon MEMS sensors owing to better sensor performance, ease of fabrication and cost effectiveness. In this paper, the development of novel polymer nanomechanical cantilever sensor platform with a high gauge factor Indium tin oxide (ITO) as piezoresistor for electrical transduction has been discussed. With simple and cost-effective polymer MEMS process integration, low temperature deposited ITO has been incorporated for efficient electromechanical transduction of SU-8 microcantilever devices. The fabricated SU-8/ITO microcantilevers were experimentally characterized for extracting the mechanical, electrical, and electromechanical properties. These SU-8/ITO devices exhibited strong negative piezoresistive behavior with the experimentally extracted gauge factor of ITO as -779. These devices show displacement sensitivity of 37 ppm/nm, which is nearly 30 times that of reported values of SU-8 cantilevers with nanocomposites as strain sensitive layer. The surface stress sensitivity is found to be 49.8 ppm [mN/m] <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> . One of the potential applications of this polymer MEMS cantilever for room temperature detection of hydrogen gas has also been demonstrated.

Impact of Bone Marrow miR-21 Expression on Acute Myeloid Leukemia T Lymphocyte Fragility and Dysfunction.

Background: Acute myeloid leukemia (AML) is a hematopoietic malignancy in which antitumor immunity is impaired. The therapeutic management of AML requires understanding the mechanisms involved in the fragility and immune dysfunction of AML T lymphocytes. Methods: In this study, T lymphocytes from healthy donors (HD) and AML patients were used. Extracellular vesicles (EVs) from leukemic cells were screened for their microRNA content and impact on T lymphocytes. Flow cytometry, transcriptomic as well as lentiviral transduction techniques were used to carry out the research. Results: We observed increased cell death of T lymphocytes from AML patients. EVs from leukemia myeloid cell lines harbored several miRNAs, including miR-21, and were able to induce T lymphocyte death. Compared to that in HD, miR-21 was overexpressed in both the bone marrow fluid and infiltrating T lymphocytes of AML patients. MiR-21 induces T lymphocyte cell death by upregulating proapoptotic gene expression. It also increases the immunosuppressive profile of T lymphocytes by upregulating the IL13, IL4, IL10, and FoxP3 genes. Conclusions: Our results demonstrate that miR-21 plays a significant role in AML T lymphocyte dysfunction and apoptosis. Targeting miR-21 may be a novel approach to restore the efficacy of the immune response against AML.