SARS-CoV-2 pathogenesis in an angiotensin II-induced heart-on-a-chip disease model and extracellular vesicle screening.

Adverse cardiac outcomes in COVID-19 patients, particularly those with preexisting cardiac disease, motivate the development of human cell-based organ-on-a-chip models to recapitulate cardiac injury and dysfunction and for screening of cardioprotective therapeutics. Here, we developed a heart-on-a-chip model to study the pathogenesis of SARS-CoV-2 in healthy myocardium established from human induced pluripotent stem cell (iPSC)-derived cardiomyocytes and a cardiac dysfunction model, mimicking aspects of preexisting hypertensive disease induced by angiotensin II (Ang II). We recapitulated cytopathic features of SARS-CoV-2-induced cardiac damage, including progressively impaired contractile function and calcium handling, apoptosis, and sarcomere disarray. SARS-CoV-2 presence in Ang II-treated hearts-on-a-chip decreased contractile force with earlier onset of contractile dysfunction and profoundly enhanced inflammatory cytokines compared to SARS-CoV-2 alone. Toward the development of potential therapeutics, we evaluated the cardioprotective effects of extracellular vesicles (EVs) from human iPSC which alleviated the impairment of contractile force, decreased apoptosis, reduced the disruption of sarcomeric proteins, and enhanced beta-oxidation gene expression. Viral load was not affected by either Ang II or EV treatment. We identified MicroRNAs miR-20a-5p and miR-19a-3p as potential mediators of cardioprotective effects of these EVs.

Combinatorial design of ionizable lipid nanoparticles for muscle-selective mRNA delivery with minimized off-target effects.

Ionizable lipid nanoparticles (LNPs) pivotal to the success of COVID-19 mRNA (messenger RNA) vaccines hold substantial promise for expanding the landscape of mRNA-based therapies. Nevertheless, the risk of mRNA delivery to off-target tissues highlights the necessity for LNPs with enhanced tissue selectivity. The intricate nature of biological systems and inadequate knowledge of lipid structure-activity relationships emphasize the significance of high-throughput methods to produce chemically diverse lipid libraries for mRNA delivery screening. Here, we introduce a streamlined approach for the rapid design and synthesis of combinatorial libraries of biodegradable ionizable lipids. This led to the identification of iso-A11B5C1, an ionizable lipid uniquely apt for muscle-specific mRNA delivery. It manifested high transfection efficiencies in muscle tissues, while significantly diminishing off-targeting in organs like the liver and spleen. Moreover, iso-A11B5C1 also exhibited reduced mRNA transfection potency in lymph nodes and antigen-presenting cells, prompting investigation into the influence of direct immune cell transfection via LNPs on mRNA vaccine effectiveness. In comparison with SM-102, while iso-A11B5C1's limited immune transfection attenuated its ability to elicit humoral immunity, it remained highly effective in triggering cellular immune responses after intramuscular administration, which is further corroborated by its strong therapeutic performance as cancer vaccine in a melanoma model. Collectively, our study not only enriches the high-throughput toolkit for generating tissue-specific ionizable lipids but also encourages a reassessment of prevailing paradigms in mRNA vaccine design. This study encourages rethinking of mRNA vaccine design principles, suggesting that achieving high immune cell transfection might not be the sole criterion for developing effective mRNA vaccines.

Chiral Luminescent Sensor Eu-BTB@d-Carnitine Applied in the Highly Effective Ratiometric Sensing of Curing Drugs and Biomarkers for Diabetes and Hypertension.

Chiral drugs are of great significance in drug development and life science because one pair of enantiomers has a different combination mode with target biological active sites, leading to a vast difference in physical activity. Metal-organic framework (MOF)-based chiral hybrid materials with specific chiral sites have excellent applications in the highly effective sensing of drug enantiomers. Sitagliptin and clonidine are effective curing drugs for controlling diabetes and hypertension, while insulin and norepinephrine are the biomarkers of these two diseases. Excessive use of sitagliptin and clonidine can cause side effects such as stomach pain, nausea, and headaches. Herein, through post-synthetic strategy, MOF-based chiral hybrid material Eu-BTB@d-carnitine (H3BTB = 1,3,5-benzenetrisbenzoic acid) was synthesized. Eu-BTB@d-carnitine has dual emission peaks at 417 and 616 nm when excited at 330 nm. Eu-BTB@d-carnitine can be applied in luminescent recognition toward sitagliptin and clonidine with high sensitivity and low detection limit (for sitagliptin detection, Ksv is 7.43 × 106 [M-1]; for clonidine detection, Ksv is 9.09 × 106 [M-1]; limit of detection (LOD) for sitagliptin is 10.21 nM, and LOD of clonidine is 8.34 nM). In addition, Eu-BTB@d-carnitine can further realize highly sensitive detection of insulin in human fluids with a high Ksv (2.08 × 106 [M-1]) and a low LOD (15.48 nM). On the other hand, norepinephrine also can be successfully discriminated by the hybrid luminescent platform of Eu-BTB@d-carnitine and clonidine with a high Ksv value of 4.79 × 106 [M-1] and a low LOD of 8.37 nM. As a result, the chiral hybrid material Eu-BTB@d-carnitine can be successfully applied in the highly effective ratiometric sensing of curing drugs and biomarkers for diabetes and hypertension.

An organ-on-a-chip model for pre-clinical drug evaluation in progressive non-genetic cardiomyopathy.

Angiotensin II (Ang II) presents a critical mediator in various pathological conditions such as non-genetic cardiomyopathy. Osmotic pump infusion in rodents is a commonly used approach to model cardiomyopathy associated with Ang II. However, profound differences in electrophysiology and pharmacokinetics between rodent and human cardiomyocytes may limit predictability of animal-based experiments. This study investigates the application of an Organ-on-a-chip (OOC) system in modeling Ang II-induced progressive cardiomyopathy. The disease model is constructed to recapitulate myocardial response to Ang II in a temporal manner. The long-term tissue cultivation and non-invasive functional readouts enable monitoring of both acute and chronic cardiac responses to Ang II stimulation. Along with mapping of cytokine secretion and proteomic profiles, this model presents an opportunity to quantitatively measure the dynamic pathological changes that could not be otherwise identified in animals. Further, we present this model as a testbed to evaluate compounds that target Ang II-induced cardiac remodeling. Through assessing the effects of losartan, relaxin, and saracatinib, the drug screening data implicated multifaceted cardioprotective effects of relaxin in restoring contractile function and reducing fibrotic remodeling. Overall, this study provides a controllable platform where cardiac activities can be explicitly observed and tested over the pathological process. The facile and high-content screening can facilitate the evaluation of potential drug candidates in the pre-clinical stage.

Driving force to detect Alzheimer's disease biomarkers: application of a thioflavine T@Er-MOF ratiometric fluorescent sensor for smart detection of presenilin 1, amyloid ß-protein and acetylcholine.

Currently, the highly sensitive detection of Alzheimer's Disease (AD) biomarkers, namely presenilin 1, amyloid ß-protein (Aß), and acetylcholine (ACh), is vital to helping us prevent and diagnose AD. In this work, a novel metal-organic framework [Er(L)(DMF)1.27]n (Er-MOF) (H3L = terphenyl-3,4'',5-tricarboxylic acid) has been synthesized by solvothermal and ultrasonic methods. Further, through the post-synthesis assembly strategy, the fluorescent dye thioflavine T (ThT) has been introduced into Er-MOF to construct a dual-emission ThT@Er-MOF ratiometric fluorescent sensor. This is the first time that ThT@Er-MOF has been successfully applied in the highly sensitive detection of three main Alzheimer's disease biomarkers in the cerebrospinal fluid through three different low cost and facile detection strategies. Firstly, with the spilted DNA strategy, this is the first time that ThT@Er-MOF can be applied in the label-free detection of SSODN (part of the presenilin 1 gene). Secondly, for the detection of Aß, because ThT can be specifically combined with Aß and has an excellent characteristic fluorescence band, the dual-emission ThT@Er-MOF sensor can be selectively applied to detect Aß over the analog protein, which shows far more sensitivity than other Aß sensors. Thirdly, through the acetylcholine esterase (AchE) enzymatic cleavage and release strategy, ThT@Er-MOF enhances the detection of acetylcholine (ACh) with a low limit of detection (LOD) value (0.03226 nM). It should be noticed that the three different detection methods are low cost and facile. This study also provides the first example of utilizing laser scanning confocal microscopy (LSCM) to investigate the fluorescence resonance energy transfer (FRET) detection mechanism by ThT@Er-MOF in more detail. The location of FRET occurrence and FRET efficiency can also be investigated by LSCM, which can be helpful to understand the FRET detection process by these unique MOF-based hybrid materials.

Solvothermal and Ultrasonic Preparation of Two Unique Cluster-Based Lu and Y Coordination Materials: Metal-Organic Framework-Based Ratiometric Fluorescent Biosensor for an Ornidazole and Ronidazole and Sensing Platform for a Biomarker of Amoeba Liver Abscess.

Through powerful solvothermal and facile ultrasonic synthetic strategies, two unique cluster-based lanthanide Lu and Y nanoporous metal organic frameworks (MOFs) have been successfully prepared, namely, {[Lu2(L)2]·2DMF·H2O}n (Lu-MOF) and [Y(L)(DMF)0.75]n (Y-MOF) (H3L = terphenyl-3,4'',5-tricarboxylic acid). In addition, both the morphologies and nanosizes of Lu-MOF and Y-MOF materials also have been deliberately tuned by adjustable ultrasonic conditions including irradiation time (40, 60, and 80 min) and power (70 w, 100 w). Currently, it is noted that the abuse of antibiotics such as ornidazole and ronidazole leads to great damage to human health, and therefore the development of highly effective and facile detection methods for ornidazole and ronidazole is quite important. Herein, to improve the fluorescent sensing sensitivity of antibiotics, Eu3+ and Tb3+ have been introduced into Lu-MOF (under a solvothermal preparation method) to fabricate a dual-emission hybrid material Eu3+/Tb3+@Lu-MOF through a postsynthesis strategy, which can be successfully applied as a self-calibrated ratiometric fluorescent sensor for ornidazole and ronidazole with high selectivity and sensitivity (the Ksv value for ornidazole is 1.0854 × 106 [M-1], and the Ksv value for ronidazole is 1.0595 × 107 [M-1]) and low detection limit values (2.85 nM for ornidazole and 26.7 nM for ronidazole). On the other hand, amoeba liver abscess (ALA) will easily lead to irregular fever, night sweats, and other tortured symptoms; C-reactive protein autoantibody (CRP Ab) is the important biomarker for the detection of ALA. Given this, Y-MOF (under the solvothermal preparation method) also has been successfully designed to combine FAM-labeled NH-ssDNA to construct the scarcely reported excellent hybrid FAM-labeled NH-ssDNA/Y-MOF sensing platform for the highly effective discrimination of CRP Ab with excellent sensitivity and selectivity in real samples such as human serum solution.

Hydrothermal Preparation of Five Rare-Earth (Re = Dy, Gd, Ho, Pr, and Sm) Luminescent Cluster-Based Coordination Materials: The First MOFs-based Ratiometric Fluorescent Sensor for Lysine and Bifunctional Sensing Platform for Insulin and Al3.

Through the powerful hydrothermal method, five rare-earth (Re = Dy, Gd, Ho, Pr, and Sm) three-dimensional (3D) cluster-based metal-organic frameworks (MOFs) have been synthesized, namely, [Dy(L)(H2O)(DMF)] n (1), {[Gd(L)(H2O)(DMF)]·DMF} n (2), {[Ho(L)(H2O)(DMF)]·0.5DMF} n (3), {[Pr(L)(H2O)(DMF)]·0.5DMF} n (4), and {[Sm(L)(H2O)1.55(DMF)0.45]·DMF} n (5; H3L = terphenyl-3,4″,5-tricarboxylic acid), which have been determined by single crystal X-ray analyses and PXRD characterization. Structural analyses reveal that, in 1-5, these L3- ligands are linked by five different rare-earth centers, forming the iso-structural nanoporous frameworks. PXRD patterns of bulky samples 1-5 also are consistent with theoretical PXRD patterns confirming their purity. Solid state photoluminesce of free H3L and 1-5 at room temperature also has been investigated indicating strong ligand-based emissions. Besides these, fluorescent dye Rhodamine B (RhB) can be introduced into MOF1 forming the composite material RhB@MOF1 with a high quantum yield of 35%. It is noted that, through deliberately tuning the morphologies of nanoparticle MOF1 under different ultrasonic conditions, RhB@MOF1 can be utilized as the first ratiometric fluorescent sensor to effectively discriminate l- and d-lysine from other amino acid molecules with high Ksv values and low LOD values. On the other hand, 2 was for the first time to be utilized as an excellent bifunctional MOFs-based sensing platform to detect insulin and Al3+ with a low detection limit in the human serum solution.

Development of a novel method for the strengthening and toughening of irradiation-sterilized bone allografts.

Reconstruction of large skeletal defects is a significant and challenging issue. Bone allografts are often used for such reconstructions. However, sterilizing bone allografts by using γ-irradiation, damages collagen and causes the bone to become weak, brittle and less fatigue resistant. In a previous study, we successfully protected the mechanical properties of human cortical bone by conducting a pre-treatment with ribose, a natural and biocompatible agent. This study focuses on examining possible mechanisms by which ribose might protect the bone. We examined the mechanical properties, crosslinking, connectivity and free radical scavenging potentials of the ribose treatment. Human cortical bone beams were treated with varying concentration of ribose (0.06-1.2 M) and γ-irradiation before testing them in 3-point bending. The connectivity and amounts of crosslinking were determined with Hydrothermal-Isometric-Tension testing and High-Performance-Liquid-Chromatography, respectively. The free radical content was measured using Electron Paramagnetic Resonance. Ribose pre-treatment improved the mechanical properties of irradiation sterilized human bone in a pre-treatment concentration-dependent manner. The 1.2 M pre-treatment provided >100% of ultimate strength of normal controls and protected 76% of the work-to-fracture (toughness) lost in the irradiated controls. Similarly, the ribose pre-treatment improved the thermo-mechanical properties of irradiation-sterilized human bone collagen in a concentration-dependent manner. Greater free radical content and pentosidine content were modified in the ribose treated bone. This study shows that the mechanical properties of irradiation-sterilized cortical bone allografts can be protected by incubating the bone in a ribose solution prior to irradiation.

[Infection of Mice with Normal Immune Function by Taenia asiatica].

The Taenia asiatica eggs pre-incubated with sodium hypochlorite solution for 4 min, 6 min and 8 mins were subcutaneously injected into mice with normal immune function(groups Al-A3 respectively, n=20 in each) and mice with immunosuppression (groups B1-B3, n=20 in each). All groups of mice began to show body discomfort on day 5 after infection and develop lumps on the back about on day 15. In groups Al-A3, animal death occurred during days 7-15, with a same survival rate of 95.0%(19/20) and infection rate of 89.4%(17/19), 73.6%(14/19) and 47.3%(9/19) respectively. In groups B1-B3, animal death occurred during days 7-50, with survival rate of 60%(13/20), 55%(11/20)and 55%(11/20) and infection rate of 76.9% (10/13), 54.5% (6/11) and 45.4% (5/11) respectively. After the scolex of cysticercus was evaginated with 15% pig bile, four suckers, an apparent rostellum and two distinct hook-like puncta structures were seen. These results indicate that mice with normal immune function can be used as a replacement of immunosuppressive mice to establish a T. asiatica oncosphere infection model. In addition, the T. asiatica eggs pre-incubated with sodium hypochlorite solution for 4 min have the strongest infection ability.

Observation of the asymmetric Bessel beams with arbitrary orientation using a digital micromirror device.

Recently, V. V. Kotlyar et al. [Opt. Lett.39, 2395 (2014)] have theoretically proposed a novel kind of three-parameter diffraction-free beam with a crescent profile, namely, the asymmetric Bessel (aB) beam. The asymmetry degree of such nonparaxial modes was shown to depend on a nonnegative real parameter c. We present a more generalized asymmetric Bessel mode in which the parameter c is a complex constant. This parameter controls not only the asymmetry degree of the mode but also the orientation of the optical crescent, and affects the energy distribution and orbital angular momentum (OAM) of the beam. As a proof of concept, the high-quality generation of asymmetric Bessel-Gauss beams was demonstrated with the super-pixel method using a digital micromirror device (DMD). We investigated the near-field properties as well as the far field features of such beams, and the experimental observations were in good agreement with the theoretical predictions. Additionally, we provided an effective way to control the beam's asymmetry and orientation, which may find potential applications in light-sheet microscopy and optical manipulation.

[Synthesis and characterization of CO-3(2-) doping nano-hydroxyapatite].

CO3(2-) doping is an effective method to increase the biological activity of nano-hydroxyapatite (n-HA). In the present study, calcium nitrate and trisodium phosphate were chosen as raw materials, with a certain amount of Na2CO3 as a source of CO-3(2-) ions, to synthesize nano-carbonate hydroxyapatite (n-CHA) slurry by solution precipitation method. The structure and micro-morphology of n-CHA were characterized by transmission electron microscope (TEM), X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FTIR) and Raman spectroscopy (RS). The results revealed that the synthetic n-HA crystals are acicular in nanometer scale and have a crystal size of 20-30 nm in diameter and 60-80 nm in length, which are similar to natural bone apatite. And the crystallinity of n-CHA crystals decreases to the increment of CO3(2-). Samples with more CO3(2) have composition and structure more similar to the bone apatite. The value of lattice parameters a decreases, value of c increases, and c/a value increases with the increase in the amount of CO3(2-), in accordance with crystal cell parameters change rule of type B replacement. In the AB mixed type (substitution OH- and PO4(3-)) CHA, IR characteristic peak of CO3(2-) out-of-plane bending vibration appears at 872 cm(-1), meanwhile, the asymmetry flexible vibration band is split into band at 1 454 cm(-1) and band at 1 420 cm(-1), while weak CO3(2)-peak appears at 1 540 cm(-1). CO3(2-) Raman peak of symmetric stretching vibration appears at 1 122 cm(-1). CO3(2-) B-type (substitution PO4(3-)) peak appeared at 1 071 cm(-1). Through the calculation of integral area ratio of PO4(3-)/ CO3(2-), OH-/CO3(2-), and PO4(3-)/OH-, low quantity CO3(2-) is B-type and high quantity CO3(2-) is A-type (substitution OH-). The results show that the synthesized apatite crystals are AB hybrid substitued nano-carbonate hydroxyapatite, however B-type replacement is the main substitute mode. Due to similarity inthe shape, size, crystal structure and growth mode, the synthesized apatite crystals can be called a kind of bone-like apatite.

The emerging role of heart-on-a-chip systems in delineating mechanisms of SARS-CoV-2-induced cardiac dysfunction.

Coronavirus disease 2019 (COVID-19) has been a major global health concern since its emergence in 2019, with over 680 million confirmed cases as of April 2023. While COVID-19 has been strongly associated with the development of cardiovascular complications, the specific mechanisms by which viral infection induces myocardial dysfunction remain largely controversial as studies have shown that the severe acute respiratory syndrome coronavirus-2 can lead to heart failure both directly, by causing damage to the heart cells, and indirectly, by triggering an inflammatory response throughout the body. In this review, we summarize the current understanding of potential mechanisms that drive heart failure based on in vitro studies. We also discuss the significance of three-dimensional heart-on-a-chip technology in the context of the current and future pandemics.

AGILE platform: a deep learning powered approach to accelerate LNP development for mRNA delivery.

Ionizable lipid nanoparticles (LNPs) are seeing widespread use in mRNA delivery, notably in SARS-CoV-2 mRNA vaccines. However, the expansion of mRNA therapies beyond COVID-19 is impeded by the absence of LNPs tailored for diverse cell types. In this study, we present the AI-Guided Ionizable Lipid Engineering (AGILE) platform, a synergistic combination of deep learning and combinatorial chemistry. AGILE streamlines ionizable lipid development with efficient library design, in silico lipid screening via deep neural networks, and adaptability to diverse cell lines. Using AGILE, we rapidly design, synthesize, and evaluate ionizable lipids for mRNA delivery, selecting from a vast library. Intriguingly, AGILE reveals cell-specific preferences for ionizable lipids, indicating tailoring for optimal delivery to varying cell types. These highlight AGILE's potential in expediting the development of customized LNPs, addressing the complex needs of mRNA delivery in clinical practice, thereby broadening the scope and efficacy of mRNA therapies.

Primitive macrophages enable long-term vascularization of human heart-on-a-chip platforms.

The intricate anatomical structure and high cellular density of the myocardium complicate the bioengineering of perfusable vascular networks within cardiac tissues. In vivo neonatal studies highlight the key role of resident cardiac macrophages in post-injury regeneration and angiogenesis. Here, we integrate human pluripotent stem-cell-derived primitive yolk-sac-like macrophages within vascularized heart-on-chip platforms. Macrophage incorporation profoundly impacted the functionality and perfusability of microvascularized cardiac tissues up to 2 weeks of culture. Macrophages mitigated tissue cytotoxicity and the release of cell-free mitochondrial DNA (mtDNA), while upregulating the secretion of pro-angiogenic, matrix remodeling, and cardioprotective cytokines. Bulk RNA sequencing (RNA-seq) revealed an upregulation of cardiac maturation and angiogenesis genes. Further, single-nuclei RNA sequencing (snRNA-seq) and secretome data suggest that macrophages may prime stromal cells for vascular development by inducing insulin like growth factor binding protein 7 (IGFBP7) and hepatocyte growth factor (HGF) expression. Our results underscore the vital role of primitive macrophages in the long-term vascularization of cardiac tissues, offering insights for therapy and advancing heart-on-a-chip technologies.

Cardiac tissue model of immune-induced dysfunction reveals the role of free mitochondrial DNA and the therapeutic effects of exosomes.

Despite tremendous progress in the development of mature heart-on-a-chip models, human cell-based models of myocardial inflammation are lacking. Here, we bioengineered a vascularized heart-on-a-chip with circulating immune cells to model severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-induced acute myocarditis. We observed hallmarks of coronavirus disease (COVID-19)-induced myocardial inflammation, as the presence of immune cells augmented the secretion of proinflammatory cytokines, triggered progressive impairment of contractile function, and altered intracellular calcium transients. An elevation of circulating cell-free mitochondrial DNA (ccf-mtDNA) was measured first in the heart-on-a-chip and then validated in COVID-19 patients with low left ventricular ejection fraction, demonstrating that mitochondrial damage is an important pathophysiological hallmark of inflammation-induced cardiac dysfunction. Leveraging this platform in the context of SARS-CoV-2-induced myocardial inflammation, we established that administration of endothelial cell-derived exosomes effectively rescued the contractile deficit, normalized calcium handling, elevated the contraction force, and reduced the ccf-mtDNA and cytokine release via Toll-like receptor-nuclear factor κB signaling axis.

Map4k4 is up-regulated and modulates granulosa cell injury and oxidative stress in polycystic ovary syndrome via activating JNK/c-JUN pathway: An experimental study.

The regulatory mechanism on granulosa cells (GCs) oxidative injury is becoming increasingly important in polycystic ovary syndrome (PCOS) studies. Serine/threonine kinase mitogen-activated protein 4 kinase 4 (Map4k4) is linked with oxidative injury and possibly associated with premature ovarian failure and ovarian dysgenesis. Herein, we investigated the function and mechanism of Map4k4 in a PCOS rat model. A microarray from GEO database identified Map4k4 was up-regulated in the ovarian of PCOS rats, and functional enrichments suggested that oxidative stress-associated changes are involved. We verified the raised Map4k4 expression in an established PCOS rat model and also in the isolated PCOS-GCs, which were consistent with the microarray data. Map4k4 knockdown in vivo contributed to regular estrous cycle, restrained steroid concentrations and ovarian injury in PCOS rats. Both Map4k4 silencing in vivo and in vitro attenuated the PCOS-related GC oxidative stress and apoptosis. Mechanically, Map4k4 activated the JNK/c-JUN signaling pathway. Importantly, a JNK agonist restored the suppressive effects of Map4k4 silencing on PCOS-induced granulosa cell injury and oxidative stress. Besides, Map4k4 may be a target gene of miR-185-5p. In conclusion, Map4k4, a potential target of miR-185-5p, is up-regulated and induces ovarian GC oxidative injury by activating JNK/c-JUN pathway in PCOS. The Map4k4/JNK/c-JUN mechanism may provide a new idea on the treatment of PCOS.

Heart-on-a-chip model of immune-induced cardiac dysfunction reveals the role of free mitochondrial DNA and therapeutic effects of endothelial exosomes.

Cardiovascular disease continues to take more human lives than all cancer combined, prompting the need for improved research models and treatment options. Despite a significant progress in development of mature heart-on-a-chip models of fibrosis and cardiomyopathies starting from induced pluripotent stem cells (iPSCs), human cell-based models of myocardial inflammation are lacking. Here, we bioengineered a vascularized heart-on-a-chip system with circulating immune cells to model SARS-CoV-2-induced acute myocarditis. Briefly, we observed hallmarks of COVID-19-induced myocardial inflammation in the heart-on-a-chip model, as the presence of immune cells augmented the expression levels of proinflammatory cytokines, triggered progressive impairment of contractile function and altered intracellular calcium transient activities. An elevation of circulating cell-free mitochondrial DNA (ccf-mtDNA) was measured first in the in vitro heart-on-a-chip model and then validated in COVID-19 patients with low left ventricular ejection fraction (LVEF), demonstrating that mitochondrial damage is an important pathophysiological hallmark of inflammation induced cardiac dysfunction. Leveraging this platform in the context of SARS-CoV-2 induced myocardial inflammation, we established that administration of human umbilical vein-derived EVs effectively rescued the contractile deficit, normalized intracellular calcium handling, elevated the contraction force and reduced the ccf- mtDNA and chemokine release via TLR-NF-kB signaling axis.

Maturation of iPSC-derived cardiomyocytes in a heart-on-a-chip device enables modeling of dilated cardiomyopathy caused by R222Q-SCN5A mutation.

To better understand sodium channel (SCN5A)-related cardiomyopathies, we generated ventricular cardiomyocytes from induced pluripotent stem cells obtained from a dilated cardiomyopathy patient harbouring the R222Q mutation, which is only expressed in adult SCN5A isoforms. Because the adult SCN5A isoform was poorly expressed, without functional differences between R222Q and control in both embryoid bodies and cell sheet preparations (cultured for 29-35 days), we created heart-on-a-chip biowires which promote myocardial maturation. Indeed, biowires expressed primarily adult SCN5A with R222Q preparations displaying (arrhythmogenic) short action potentials, altered Na+ channel biophysical properties and lower contractility compared to corrected controls. Comprehensive RNA sequencing revealed differential gene regulation between R222Q and control biowires in cellular pathways related to sarcoplasmic reticulum and dystroglycan complex as well as biological processes related to calcium ion regulation and action potential. Additionally, R222Q biowires had marked reductions in actin expression accompanied by profound sarcoplasmic disarray, without differences in cell composition (fibroblast, endothelial cells, and cardiomyocytes) compared to corrected biowires. In conclusion, we demonstrate that in addition to altering cardiac electrophysiology and Na+ current, the R222Q mutation also causes profound sarcomere disruptions and mechanical destabilization. Possible mechanisms for these observations are discussed.

UV-irradiating synthesis of cyclodextrin-silver nanocluster decorated TiO2 nanoparticles for photocatalytic enhanced anticancer effect on HeLa cancer cells.

Titanium dioxide (TiO2) has emerged as a viable choice for several biological and environmental applications because of its high efficiency, cheap cost, and high photostability. In pursuit of this purpose, the research of its many forms has been influenced by these unique aspects. The development of novel TiO2-based hybrid materials with enhanced photocatalytically induced anticancer activity has gained tremendous attention. Here, we have developed a novel photocatalytic material (TiO2-Ag NPs@-CD) by decorating ultrasmall silver nanoparticles (Ag NPs) with per-6-thio-ß-cyclodextrin (SH-ß-CD) on TiO2 NPs. TiO2-Ag NPs@-CD were characterized by employing various characterization techniques and evaluated for their anticancer activity against HeLa cancer cells using an MTT assay. The biocompatibility of the designed nanoparticles was determined on two normal cell lines, namely, 3T3 and human mesenchymal stem cells (hMSCs). The results show that the TiO2-Ag NPs@-CD induced superior cytotoxic effects on HeLa cancer cells at a concentration of 64 µg/ml. Live-dead staining and oxidative stress investigations demonstrated that cell membrane disintegration and ROS-induced oxidative stress generated by TiO2-Ag NPs@-CD inside HeLa cancer cells are the contributing factors to their exceptional anti-cancer performance. Moreover, TiO2-Ag NPs@-CD exhibited good biocompatibility with 3T3 and hMSCs. These results indicated that the combination of all three components-a silver core, SH-ß-CD ligands, and TiO2 nanoparticles-produced a synergistic anticancer effect. Hence, the TiO2-Ag NPs@-CD is a promising material that can be employed for different biological applications.