In situ formed depot of elastin-like polypeptide-hirudin fusion protein for long-acting antithrombotic therapy.

Thrombosis, induced by abnormal coagulation or fibrinolytic systems, is the most common pathology associated with many life-threatening cardio-cerebrovascular diseases. However, first-line anticoagulant drugs suffer from rapid drug elimination and risk of hemorrhagic complications. Here, we developed an in situ formed depot of elastin-like polypeptide (ELP)-hirudin fusion protein with a prodrug-like feature for long-term antithrombotic therapy. Highly secretory expression of the fusion protein was achieved with the assistance of the Ffu312 tag. Integration of hirudin, ELP, and responsive moiety can customize fusion proteins with properties of adjustable in vivo retention and controllable recovery of drug bioactivity. After subcutaneous injection, the fusion protein can form a reservoir through temperature-induced coacervation of ELP and slowly diffuse into the blood circulation. The biological activity of hirudin is shielded due to the N-terminal modification, while the activated key proteases upon thrombus occurrence trigger the cleavage of fusion protein together with the release of hirudin, which has antithrombotic activity to counteract thrombosis. We substantiated that the optimized fusion protein produced long-term antithrombotic effects without the risk of bleeding in multiple animal thrombosis models.

The novel small molecule E0924G dually regulates bone formation and bone resorption through activating the PPARδ signaling pathway to prevent bone loss in ovariectomized rats and senile mice.

Osteoporosis is particularly prevalent among postmenopausal women and the elderly. In the present study, we investigated the effect of the novel small molecule E0924G (N-(4-methoxy-pyridine-2-yl)-5-methylfuran-2-formamide) on osteoporosis. E0924G significantly increased the protein expression levels of osteoprotegerin (OPG) and runt-related transcription factor 2 (RUNX2), and thus significantly promoted osteogenesis in MC3T3-E1 cells. E0924G also significantly decreased osteoclast differentiation and inhibited bone resorption and F-actin ring formation in receptor activator of NF-κB ligand (RANKL)-induced osteoclasts from RAW264.7 macrophages. Importantly, oral administration of E0924G in both ovariectomized (OVX) rats and SAMP6 senile mice significantly increased bone mineral density and decreased bone loss compared to OVX controls or SAMR1 mice. Further mechanistic studies showed that E0924G could bind to and then activate peroxisome proliferator-activated receptor delta (PPARδ), and the pro-osteoblast effect and the inhibition of osteoclast differentiation induced by E0924G were significantly abolished when PPARδ was knocked down or inhibited. In conclusion, these data strongly suggest that E0924G has the potential to prevent OVX-induced and age-related osteoporosis by dual regulation of bone formation and bone resorption through activation of the PPARδ signaling pathway.

Scalable Nanotrap Matrix Enhanced Electroporation for Intracellular Recording of Action Potential.

Electrophysiological recording, as a long-sought objective, plays a crucial role in fundamental biomedical research and practical clinical applications. The challenge in developing electrophysiological detection platforms is to combine simplicity, stability, and sensitivity in the same device. In this study, we develop a nanotrapped microelectrode based on a porous PET membrane, which is compatible with large-scale microtechnologies. The nanotraps can promote the protrusion of the local cell membrane in the hollow center and offer a unique nanoedge structure for tight sealing and effective electroporation. We demonstrate that scalable nanotraps can enhance cell-electrode coupling and perform high-quality intracellular recording. Further, the nanoedge-enhanced electroporation and minimally invasive nanotrapped recordings afford much longer intracellular access of over 100 min and permit consecutive electroporation events in a short period of time. This study suggests that the geometry-regulating strategy of the cell-electrode nanointerface could significantly improve the intracellular recording performance of a nanopatterned electrode.

Glucose-Responsive Charge-Switchable Lipid Nanoparticles for Insulin Delivery.

Lipid nanoparticle-based drug delivery systems have a profound clinical impact on nucleic acid-based therapy and vaccination. Recombinant human insulin, a negatively-charged biomolecule like mRNA, may also be delivered by rationally-designed positively-charged lipid nanoparticles with glucose-sensing elements and be released in a glucose-responsive manner. Herein, we have designed phenylboronic acid-based quaternary amine-type cationic lipids that can self-assemble into spherical lipid nanoparticles in an aqueous solution. Upon mixing insulin and the lipid nanoparticles, a heterostructured insulin complex is formed immediately arising from the electrostatic attraction. In a hyperglycemia-relevant glucose solution, lipid nanoparticles become less positively charged over time, leading to reduced attraction and subsequent insulin release. Compared with native insulin, this lipid nanoparticle-based glucose-responsive insulin shows prolonged blood glucose regulation ability and blood glucose-triggered insulin release in a type 1 diabetic mouse model.

Advances in Multidimensional Cardiac Biosensing Technologies: From Electrophysiology to Mechanical Motion and Contractile Force.

Cardiovascular disease is currently a leading killer to human, while drug-induced cardiotoxicity remains the main cause of the withdrawal and attrition of drugs. Taking clinical correlation and throughput into account, cardiomyocyte is perfect as in vitro cardiac model for heart disease modeling, drug discovery, and cardiotoxicity assessment by accurately measuring the physiological multiparameters of cardiomyocytes. Remarkably, cardiomyocytes present both electrophysiological and biomechanical characteristics due to the unique excitation-contraction coupling, which plays a significant role in studying the cardiomyocytes. This review mainly focuses on the recent advances of biosensing technologies for the 2D and 3D cardiac models with three special properties: electrophysiology, mechanical motion, and contractile force. These high-performance multidimensional cardiac models are popular and effective to rebuild and mimic the heart in vitro. To help understand the high-quality and accurate physiologies, related detection techniques are highly demanded, from microtechnology to nanotechnology, from extracellular to intracellular recording, from multiple cells to single cell, and from planar to 3D models. Furthermore, the characteristics, advantages, limitations, and applications of these cardiac biosensing technologies, as well as the future development prospects should contribute to the systematization and expansion of knowledge.

A magnetic beads-based portable flow cytometry immunosensor for in-situ detection of marine biotoxin.

Okadaic acid (OA), a representative diarrhetic shellfish poisoning toxin, mainly produced by toxigenic dinoflagellates, has significant hazard to public health. Traditional methods for detection of OA can not give the consideration to the need of rapid, high sensitive, quantitative and in-situ detection at the same time. Herein, a new effective detection method of OA was developed based on fluorescence immunosensor and flow cytometry (FCM). In this assay, Streptavidin-coated magnetic beads (MBs) were used as the supporter to immobilize the biotinylated OA. Modified MBs competed with the free OA in the sample solution to bind with the anti-OA monoclonal antibody (OA-MAb). The R-phycoerythrin (R-PE) dye labeled IgG was served as a secondary antibody to perform fluorescence detection. A portable flow cytometry was applied for the in-situ fluorescence quantification. The results showed that the OA concentration was inversely proportional to the R-PE fluorescence intensity. The detection method took within 50 min with a limit of detection (LOD) was 0.05 µg/L and range from 0.2 to 20 µg/L for OA detection. Moreover, the matrix effect and the recovery rate were assessed during real sample measurement, showing a high recovery. Performance features such as high sensitivity, low LOD, speediness and simplicity of the analysis protocol, shows this biosensing-systems as a promising tool for routine use.

Bionic 3D spheroids biosensor chips for high-throughput and dynamic drug screening.

To perform the drug screening, planar cultured cell models are commonly applied to test efficacy and toxicity of drugs. However, planar cultured cells are different from the human 3D organs or tissues in vivo. To simulate the human 3D organs or tissues, 3D spheroids are developed by culturing a small aggregate of cells which reside around the extracellular matrix and interact with other cells in liquid media. Here we apply lung carcinoma cell lines to engineer the 3D lung cancer spheroid-based biosensor using the interdigitated electrodes for drug efficacy evaluation. The results show 3D spheroid had higher drug resistance than the planar cell model. The anticarcinogen inhibition on different 3D lung cancer spheroid models (A549, H1299, H460) can be quantitatively evaluated by electric impedance sensing. Besides, we delivered combination of anticarcinogens treatments to A549 spheroids which is commonly used in clinic treatment, and found the synergistic effect of cisplatin plus etoposide had higher drug response. To simultaneously test the drug efficacy and side effects on multi-organ model with circulatory system, a connected multiwell interdigitated electrode arraywas applied to culture different organoid spheroids. Overall, the organization of 3D cancer spheroids-based biosensor, which has higher predictive value for drug discovery and personalized medicine screening, is expected to be well applied in the area of pharmacy and clinical medicine.

Micronano Synergetic Three-Dimensional Bioelectronics: A Revolutionary Breakthrough Platform for Cardiac Electrophysiology.

Cardiovascular diseases (CVDs) are the leading cause of mortality and therefore pose a significant threat to human health. Cardiac electrophysiology plays a crucial role in the investigation and treatment of CVDs, including arrhythmia. The long-term and accurate detection of electrophysiological activity in cardiomyocytes is essential for advancing cardiology and pharmacology. Regarding the electrophysiological study of cardiac cells, many micronano bioelectric devices and systems have been developed. Such bioelectronic devices possess unique geometric structures of electrodes that enhance quality of electrophysiological signal recording. Though planar multielectrode/multitransistors are widely used for simultaneous multichannel measurement of cell electrophysiological signals, their use for extracellular electrophysiological recording exhibits low signal strength and quality. However, the integration of three-dimensional (3D) multielectrode/multitransistor arrays that use advanced penetration strategies can achieve high-quality intracellular signal recording. This review provides an overview of the manufacturing, geometric structure, and penetration paradigms of 3D micronano devices, as well as their applications for precise drug screening and biomimetic disease modeling. Furthermore, this review also summarizes the current challenges and outlines future directions for the preparation and application of micronano bioelectronic devices, with an aim to promote the development of intracellular electrophysiological platforms and thereby meet the demands of emerging clinical applications.

Label-free and highly-sensitive detection of calcium ions using a silicon-on-sapphire light-addressable potentiometric sensor.

BACKGROUND: Ionic calcium (Ca2+) plays a crucial role in maintaining normal physiological and biochemical functions within the human body. Detecting the concentration of Ca2+ is of utmost significance for various purposes, including disease screening, cellular metabolism research, and evaluating drug effectiveness. However, current detection approaches such as fluorescence and colorimetry face limitations due to complex labeling techniques and the inability to track changes in Ca2+ concentration. In recent years, extensive research has been conducted in this field to explore label-free and efficient approaches. RESULTS: In this study, a novel light-addressed potentiometric sensor (LAPS) using silicon-on-sapphire technology, has been successfully developed for Ca2+ sensing. The Ca2+-sensitive LAPS achieved a wide-range detection of Ca2+, ranging from 10-2 M to 10-7 M, with an impressive detection limit of 100 nM. These advancements are attributed to the ultra-thin silicon layer, silicon dioxide layer, and solid-state silicon rubber sensitive membrane around 6 µm. Furthermore, the sensor demonstrated the ability to dynamically monitor fluctuations in Ca2+ concentration ranging from 10-9 M to 10-2 M within a solution. Its remarkable selectivity, specificity, and long-term stability have facilitated its successful application in the detection of Ca2+ in human serum and urine. SIGNIFICANCE AND NOVELTY: This work presents a Ca2+-sensitive sensor that combines a low detection limit and a wide detection range. The development represents the emergence of a label-free and rapid Ca2+ detection tool with immense prospects in home-based health monitoring, community disease screening, as well as cellular metabolism, and drug screening evaluations.

[Multivariate correlation analysis of T1S and C7S].

OBJECTIVE: To determine whether C7 angles (C7 slope, C7S) could replace T1 angles (T1 slope, T1S) by correlation analysis of T1S and C7S. METHODS: A total of 442 patients from July 2015 to July 2020 in outpatient and inpatient department were enrolled retrospectively, and 259 patients who could identify the upper endplate of T1 were screened out . Of them, there were 145 males and 114 females, aged from 20 to 83 years old with an average of (58.6±11.2) years, including 163 patients with cervical spine surgery and 96 non-surgical patients. Patients were stratified by sex, age, cervical kyphosis, cervical alignment imbalance, and cervical spine surgery. These 259 patients included 145 cases in the male group, 114 cases in the female group;76 cases in the youth group (<40 years old), 109 cases in the middle-aged group (40 to 60 years old), and 74 cases in the elderly group(>60 years old); 92 cases in the cervical kyphosis group, 167 cases in the non-kyphosis group;51 cases in the cervical sequence imbalance group, 208 cases in the non-imbalance group;163 cases in the cervical surgery group, 96 cases in the non-operation group. The correlations of C7S and T1S in various modalities groups were analyzed. RESULTS: Of 442 patients, the recognition rate of upper endplate of T1 was 58.6%(259/442), and that of C7 was 90.7%. The mean T1S and C7S of the 259 patients were (24.5±8.0)° [(25.9±7.7)° in the male group and (23.7±6.9)° in the female group] and (20.8±7.3)° [(22.5±7.5)° in the male group and(19.7±5.8)° in the female group], respectively. The total correlation coefficient between C7S and T1S was r=0.89, R2=0.79, and the linear regression equation was T1S=0.91×C7S+4.35. In the above general information and the grouping of deformity factors, T1S was highly correlated with C7S(r value 0.85 to 0.92, P<0.05). CONCLUSION: There is a high correlation between T1S and C7S in different factor groups. For cases where T1S cannot be measured, C7S can be used to provide guidance and reference for evaluating the sagittal balance of the spine, analyzing the condition, and formulating surgical plans.

Progress in optical sensors-based uric acid detection.

The escalating number of patients affected by various diseases, such as gout, attributed to abnormal uric acid (UA) concentrations in body fluids, has underscored the need for rapid, efficient, highly sensitive, and stable UA detection methods and sensors. Optical sensors have garnered significant attention due to their simplicity, cost-effectiveness, and resistance to electromagnetic interference. Notably, research efforts have been directed towards UA on-site detection, enabling daily monitoring at home and facilitating rapid disease screening in the community. This review aims to systematically categorize and provide detailed descriptions of the notable achievements and emerging technologies in UA optical sensors over the past five years. The review highlights the advantages of each sensor while also identifying their limitations in on-site applications. Furthermore, recent progress in instrumentation and the application of UA on-site detection in body fluids is discussed, along with the existing challenges and prospects for future development. The review serves as an informative resource, offering technical insights and promising directions for future research in the design and application of on-site optical sensors for UA detection.

Enzyme-free and wide-range portable colorimetric sensing system for uric acid and hydrogen peroxide based on copper nanoparticles.

Uric acid (UA) is the final product of purine metabolism. A high concentration of UA in body fluid may lead to kidney stones, gout, and some cardiovascular diseases. Therefore, the non-invasive daily monitoring of UA is of great significance for both hyperuricemia patients and fit people. However, most of the current detection methods for UA are enzyme-dependent which limits the application scenarios and lacks portable instruments for on-site detection, including optics and electrochemistry. In this work, an enzyme-free and wide-range colorimetric sensor for UA and H2O2 detection was developed based on a mercaptosuccinic acid (MSA)-modified Cu nanoparticles (CuNPs). Under the action of UA or H2O2, with the cleavage of MSAs on the CuNPs surface, small Cu particles are further aggregated into larger particles with a lightning violet color. With the employment of the multi-channel handheld automatic photometer (MHAP), the concentration of UA and H2O2 can be determined on-site according to the absorbance measurement by the photodiodes. The linear range of UA was 5 µM-4.5 mM with the limit of detection (LOD) of 3.7 µM, while the linear range of H2O2 was 5 mM-500 mM and 5 µM-5 mM with the LOD of 4.3 µM. This approach has been applied to the detection of UA in human urine, providing more possibilities for non-invasive home health monitoring, community medical diagnosis, and broader prospects of on-site disease detection.

Mimicking the Biological Sense of Taste In Vitro Using a Taste Organoids-on-a-Chip System.

Thanks to the gustatory system, humans can experience the flavors in foods and drinks while avoiding the intake of some harmful substances. Although great advances in the fields of biotechnology, microfluidics, and nanotechnologies have been made in recent years, this astonishing recognition system can hardly be replaced by any artificial sensors designed so far. Here, taste organoids are coupled with an extracellular potential sensor array to form a novel bioelectronic organoid and developed a taste organoids-on-a-chip system (TOS) for highly mimicking the biological sense of taste ex vivo with high stability and repeatability. The taste organoids maintain key taste receptors expression after the third passage and high cell viability during 7 days of on-chip culture. Most importantly, the TOS not only distinguishs sour, sweet, bitter, and salt stimuli with great specificity, but also recognizes varying concentrations of the stimuli through an analytical method based on the extraction of signal features and principal component analysis. It is hoped that this bioelectronic tongue can facilitate studies in food quality controls, disease modelling, and drug screening.

Material design for oral insulin delivery.

Frequent insulin injections remain the primary method for controlling the blood glucose level of individuals with diabetes mellitus but are associated with low compliance. Accordingly, oral administration has been identified as a highly desirable alternative due to its non-invasive nature. However, the harsh gastrointestinal environment and physical intestinal barriers pose significant challenges to achieving optimal pharmacological bioavailability of insulin. As a result, researchers have developed a range of materials to improve the efficiency of oral insulin delivery over the past few decades. In this review, we summarize the latest advances in material design that aim to enhance insulin protection, permeability, and glucose-responsive release. We also explore the opportunities and challenges of using these materials for oral insulin delivery.

Biomimetic integrated gustatory and olfactory sensing array based on HL-1 cardiomyocyte facilitating drug screening for tachycardia treatment.

The ectopic co-expression of taste and olfactory receptors in cardiomyocytes provides not only possibilities for the construction of biomimetic gustatory and olfactory sensors but also promising novel therapeutic targets for tachycardia treatment. Here, bitter taste and olfactory receptors endogenously expressed in HL-1 cells were verified by RT-PCR and immunofluorescence staining. Then HL-1 cardiomyocyte-based integrated gustatory and olfactory sensing array coupling with the microelectrode array (MEA) was first constructed for drugs screening and evaluation for tachycardia treatment. The MEA sensor detected the extracellular field potentials and reflected the systolic-diastolic properties of cardiomyocytes in real time in a label-free and non-invasive way. The in vitro tachycardia model was constructed using isoproterenol as the stimulator. The proposed sensing array facilitated potential drug screening for tachycardia treatment, such as salicin, artemisinin, xanthotoxin, and azelaic acid which all activated specific receptors on HL-1 cells. IC50 values for four potential drugs were calculated to be 0.0036 µM, 309.8 µM, 14.68 µM, and 0.102 µM, respectively. Visualization analysis with heatmaps and PCA cluster showed that different taste and odorous drugs could be easily distinguished. The mean inter-class Euclidean distance between different bitter drugs was 1.681, which was smaller than the distance between bitter and odorous drugs of 2.764. And the inter-class distance was significantly higher than the mean intra-class Euclidean distance of 1.172. In summary, this study not only indicates a new path for constructing novel integrated gustatory and olfactory sensors but also provides a powerful tool for the quantitative evaluation of potential drugs for tachycardia treatment.

Evaluating the efficacy and cardiotoxicity of EGFR-TKI AC0010 with a novel multifunctional biosensor.

Non-small cell lung cancer (NSCLC) is a leading cause of cancer mortality worldwide. Although epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) have dramatically improved the life expectancy of patients with NSCLC, concerns about TKI-induced cardiotoxicities have increased. AC0010, a novel third-generation TKI, was developed to overcome drug resistance induced by EGFR-T790M mutation. However, the cardiotoxicity of AC0010 remains unclear. To evaluate the efficacy and cardiotoxicity of AC0010, we designed a novel multifunctional biosensor by integrating microelectrodes (MEs) and interdigital electrodes (IDEs) to comprehensively evaluate cell viability, electrophysiological activity, and morphological changes (beating of cardiomyocytes). The multifunctional biosensor can monitor AC0010-induced NSCLC inhibition and cardiotoxicity in a quantitative, label-free, noninvasive, and real-time manner. AC0010 was found to significantly inhibit NCI-H1975 (EGFR-L858R/T790M mutation), while weak inhibition was found for A549 (wild-type EGFR). Negligible inhibition was found in the viabilities of HFF-1 (normal fibroblasts) and cardiomyocytes. With the multifunctional biosensor, we found that 10 µM AC0010 significantly affected the extracellular field potential (EFP) and mechanical beating of cardiomyocytes. The amplitude of EFP continuously decreased after AC0010 treatment, while the interval decreased first and then increased. We analyzed the change in the systole time (ST) and diastole time (DT) within a beating interval and found that the DT and DT/beating interval rate decreased within 1 h after AC0010 treatment. This result probably indicated that the relaxation of cardiomyocytes was insufficient, which may further aggravate the dysfunction. Here, we found that AC0010 significantly inhibited EGFR-mutant NSCLC cells and impaired cardiomyocyte function at low concentrations (10 µM). This is the first study in which the risk of AC0010-induced cardiotoxicity was evaluated. In addition, novel multifunctional biosensors can comprehensively evaluate the antitumor efficacy and cardiotoxicity of drugs and candidate compounds.

Blue-ringed octopus-inspired microneedle patch for robust tissue surface adhesion and active injection drug delivery.

Intratissue topical medication is important for the treatment of cutaneous, mucosal or splanchnic diseases. However, penetrating surface barriers to providing adequate and controllable drug delivery while guaranteeing adhesion in bodily fluids remains challenging. Here, the predatory behavior of the blue-ringed octopus inspired us with a strategy to improve topical medication. For effective intratissue drug delivery, the active injection microneedles were prepared in a manner inspired by the teeth and venom secretion of blue-ringed octopus. With on demand release function guided by temperature-sensitive hydrophobic and shrinkage variations, these microneedles can supply adequate drug delivery at an early stage and then achieve the long-term release stage. Meanwhile, the bionic suction cups were developed to facilitate microneedles to stay firmly in place (>10 kilopascal) when wet. With wet bonding ability and multiple delivery mode, this microneedle patch achieved satisfactory efficacy, such as accelerating the ulcers' healing speed or halting early tumor progression.

A Review on Pretreatment and Analysis Methods of Polyether Antibiotics in Complex Samples.

Polyether antibiotics (PAs) are the anti-coccidiosis drugs used for treating and preventing coccidiosis. Studies show the residues of these antibiotics in food cause adversities and threaten human health. PAs thus need robust, rugged, and accurate methods for their analysis. This review encompasses pretreatment and detection methods of PAs in diverse matrices since 2010. Both conventional and developed methods are part of the pretreatments, such as dispersive liquid-liquid microextraction, solid-phase extraction, solid-phase microextraction, solvent front position extraction, QuEChERS (Quick Easy Cheap Effective Rugged and Safe), supercritical fluid extraction, and others. The analysis methods involve liquid chromatography coupled with detectors, sensors, etc. The pros and cons of various techniques for PAs have been discussed and future tendencies are proposed.

Progress of pretreatment and analytical methods for PAs are summarized.Comparisons between different mass analyzers are discussed in detail.Novel materials in microextraction methods are depicted.

Langmuir-Blodgett-Mediated Formation of Antibacterial Microneedles for Long-Term Transdermal Drug Delivery.

Microneedles (MNs) have become versatile platforms for minimally invasive transdermal drug delivery devices. However, there are concerns about MN-induced skin infections with long-term transdermal administration. Using the Langmuir-Blodgett (LB) technique, a simple method for depositing antibacterial nanoparticles of various shapes, sizes, and compositions onto MNs is developed. This strategy has merits over conventional dip coating techniques, including controlled coating layers, uniform and high coverage, and a straightforward fabrication process. This provides MNs with a fast-acting and long-lasting antibacterial effect. This study demonstrates that antibacterial MNs achieve superior bacterial elimination in vitro and in vivo without sacrificing payload capacity, drug release, or mechanical strength. It is believed that such a functional nanoparticle coating technique offers a platform for the expansion of MNs function, especially in long-term transdermal drug delivery fields.

Quantifying the Compressive Force of 3D Cardiac Tissues via Calculating the Volumetric Deformation of Built-In Elastic Gelatin Microspheres.

Quantifying cardiac contractile force is of paramount important in studying mechanical heart failure and screening therapeutic drugs. However, most existing methods can only measure the in-plane component of twitch force of cardiomyocytes, such that mismatching the centripetal compressive stress of heart beating in physiology. Here, a non-destructive method is developed for quantifying the compressive stress and mapping the distribution of the local stress within the 3D cardiac tissues. In detail, elastic gelatin microspheres labeled with fluorescence beads are fabricated by microfluidic chips with high throughput, and they serve as built-in pressure sensors which are wrapped by cardiomyocytes in 3D tissues. The deformation of microspheres and the displacements of fluorescent beads induced by the contraction of cardiomyocytes are demonstrated to characterize the amount and distribution of the centripetal compressive stress. Further, the method shows a potent capability to locally quantify contractile force variation of 3D cardiac tissues, which is induced by agonist (norepinephrine) and inhibitor (blebbistatin). On the whole, the method significantly improves the 3D measurement of mechanical force in vitro and provides a solution for locally quantifying the compressive stress within engineered cardiac tissues.