Approaches to form flexible biosensors require strategies to tune materials for various biomedical applications. We report a facile approach using photolithography to fabricate ...poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) sensors on a fully biodegradable and flexible silk protein fibroin support. A benchtop photolithographic setup is used to fabricate high fidelity and high resolution PEDOT:PSS microstructures over a large (cm) area using only water as the solvent. Using the conductive micropatterns as working electrodes, we demonstrate biosensors with excellent electrochemical activity and stability over a number of days. The fabricated biosensors display excellent nonspecific detection of dopamine and ascorbic acid with high sensitivity. These devices are mechanically flexible, optically transparent, electroactive, cytocompatible and biodegradable. The benign fabrication protocol allows the conducting ink to function as a matrix for enzymes as shown by a highly sensitive detection of glucose. These sensors can retain their properties under repeated mechanical deformations, but are completely degradable under enzymatic action. The reported technique is scalable and can be used to develop sensitive, robust, and inexpensive biosensors with controllable biodegradability, leading to applications in transient or implantable bioelectronics and optoelectronics.
•Facile and high resolution photolithographic process for patterning conducting polymers using silk protein carriers is shown.•Micropatterned ink of PEDOT:PSS on flexible fibroin sheets is used to form an all-organic, degradable, bioelectronic device.•Highly sensitive biosensors are shown with and without enzymes.•The sensors are mechanically robust under flexure and retain structure and electrochemical properties.
Genome-wide association studies (GWAS) have identified chromosomal loci that affect risk of coronary heart disease (CHD) independent of classical risk factors. One such association signal has been ...identified at 6q23.2 in both Caucasians and East Asians. The lead CHD-associated polymorphism in this region, rs12190287, resides in the 3' untranslated region (3'-UTR) of TCF21, a basic-helix-loop-helix transcription factor, and is predicted to alter the seed binding sequence for miR-224. Allelic imbalance studies in circulating leukocytes and human coronary artery smooth muscle cells (HCASMC) showed significant imbalance of the TCF21 transcript that correlated with genotype at rs12190287, consistent with this variant contributing to allele-specific expression differences. 3' UTR reporter gene transfection studies in HCASMC showed that the disease-associated C allele has reduced expression compared to the protective G allele. Kinetic analyses in vitro revealed faster RNA-RNA complex formation and greater binding of miR-224 with the TCF21 C allelic transcript. In addition, in vitro probing with Pb2+ and RNase T1 revealed structural differences between the TCF21 variants in proximity of the rs12190287 variant, which are predicted to provide greater access to the C allele for miR-224 binding. miR-224 and TCF21 expression levels were anti-correlated in HCASMC, and miR-224 modulates the transcriptional response of TCF21 to transforming growth factor-β (TGF-β) and platelet derived growth factor (PDGF) signaling in an allele-specific manner. Lastly, miR-224 and TCF21 were localized in human coronary artery lesions and anti-correlated during atherosclerosis. Together, these data suggest that miR-224 interaction with the TCF21 transcript contributes to allelic imbalance of this gene, thus partly explaining the genetic risk for coronary heart disease associated at 6q23.2. These studies implicating rs12190287 in the miRNA-dependent regulation of TCF21, in conjunction with previous studies showing that this variant modulates transcriptional regulation through activator protein 1 (AP-1), suggests a unique bimodal level of complexity previously unreported for disease-associated variants.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
High‐resolution micropatterning of a PEDOT:PSS conducting‐polymer–silksericin composite is presented using a water‐based, benchtop photolithographic process. Conducting microstructures formed on a ...flexible silk fibroin sheet allow a fully organic, flexible bioelectronic device. Large‐area microfabricated devices such as biosensors that are biocompatible and degradable over a controlled period of time can be formed.
Flexible and thin-film devices are of great interest in epidermal and implantable bioelectronics. The integration of energy storage and delivery devices such as supercapacitors (SCs) with properties ...such as flexibility, miniaturization, biocompatibility, and degradability are sought for such systems. Reducing e-waste and using sustainable materials and processes are additional desirable qualities. Herein, a silk protein-based biocompatible and degradable thin-film microSC (μSC) is reported. A protein carrier with the conducting polymer poly(3,4-ethylenedioxythiophene) polystyrene sulfonate and reduced graphene oxide dopant is used as a photopatternable biocomposite ink. Active electrodes are fabricated using photolithography under benign conditions, using only water as the solvent. These electrodes are printed on flexible protein sheets to form degradable, organic devices with a benign agarose–NaCl gel electrolyte. High capacitance, power density, cycling stability over 500 cycles, and the ability to power a light-emitting diode are shown. The device is flexible, can sustain cyclic mechanical stresses over 450 cycles, and retain capacitive properties over several days in liquid. Significantly, the μSCs are cytocompatible and completely degraded over the period of ∼1 month. By precise control of the device configuration, these silk protein-based, all-polymer organic devices can be designed to be tunably transient and provide viable alternatives for powering flexible and implantable bioelectronics.
OBJECTIVE—The G-protein–coupled receptor APJ and its ligand apelin are highly expressed in the pulmonary vasculature, but their function in this vascular bed is unclear. We hypothesized that ...disruption of apelin signaling would lead to worsening of the vascular remodeling associated with pulmonary hypertension (PH).
METHODS AND RESULTS—We found that apelin-null mice developed more severe PH compared with wild-type mice when exposed to chronic hypoxia. Micro-computed tomography of the pulmonary arteries demonstrated significant pruning of the microvasculature in the apelin-null mice. Apelin-null mice had a significant reduction of serum nitrate levels. This was secondary to downregulation of endothelial nitric oxide synthase (eNOS), which was associated with reduced expression of Kruppel-like factor 2 (KLF2), a known regulator of eNOS expression. In vitro knockdown studies targeting apelin in human pulmonary artery endothelial cells demonstrated decreased eNOS and KLF2 expression, as well as impaired phosphorylation of AMP-activated kinase and eNOS. Moreover, serum apelin levels of patients with PH were significantly lower than those of controls.
CONCLUSION—These data demonstrate that disruption of apelin signaling can exacerbate PH mediated by decreased activation of AMP-activated kinase and eNOS, and they identify this pathway as a potentially important therapeutic target for treatment of this refractory human disease.
Coronary heart disease (CHD) is the leading cause of mortality in both developed and developing countries worldwide. Genome-wide association studies (GWAS) have now identified 46 independent ...susceptibility loci for CHD, however, the biological and disease-relevant mechanisms for these associations remain elusive. The large-scale meta-analysis of GWAS recently identified in Caucasians a CHD-associated locus at chromosome 6q23.2, a region containing the transcription factor TCF21 gene. TCF21 (Capsulin/Pod1/Epicardin) is a member of the basic-helix-loop-helix (bHLH) transcription factor family, and regulates cell fate decisions and differentiation in the developing coronary vasculature. Herein, we characterize a cis-regulatory mechanism by which the lead polymorphism rs12190287 disrupts an atypical activator protein 1 (AP-1) element, as demonstrated by allele-specific transcriptional regulation, transcription factor binding, and chromatin organization, leading to altered TCF21 expression. Further, this element is shown to mediate signaling through platelet-derived growth factor receptor beta (PDGFR-β) and Wilms tumor 1 (WT1) pathways. A second disease allele identified in East Asians also appears to disrupt an AP-1-like element. Thus, both disease-related growth factor and embryonic signaling pathways may regulate CHD risk through two independent alleles at TCF21.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Coronary artery disease (CAD) is the leading cause of mortality and morbidity, driven by both genetic and environmental risk factors. Meta-analyses of genome-wide association studies have identified ...>150 loci associated with CAD and myocardial infarction susceptibility in humans. A majority of these variants reside in non-coding regions and are co-inherited with hundreds of candidate regulatory variants, presenting a challenge to elucidate their functions. Herein, we use integrative genomic, epigenomic and transcriptomic profiling of perturbed human coronary artery smooth muscle cells and tissues to begin to identify causal regulatory variation and mechanisms responsible for CAD associations. Using these genome-wide maps, we prioritize 64 candidate variants and perform allele-specific binding and expression analyses at seven top candidate loci: 9p21.3, SMAD3, PDGFD, IL6R, BMP1, CCDC97/TGFB1 and LMOD1. We validate our findings in expression quantitative trait loci cohorts, which together reveal new links between CAD associations and regulatory function in the appropriate disease context.
•A high resolution photolithographic process for patterning PEDOT:PSS is shown.•Conductive photoink is micropatterned on ITO substrates using only water as solvent.•Robust microelectrodes ...significantly improve the electrochemical properties of ITO.•Highly sensitive biosensors are shown for detecting dopamine in presence of ascorbic acid.•Facile processing allows encapsulation of enzymes for multiplexed sensing.
Improving the performance of electrochemical sensors based on indium tin oxide (ITO) can be achieved via intrinsically conducting polymers such as poly (3, 4 ethylenedioxythiophene): polystyrene sulfonate (PEDOT:PSS). However micropatterning of PEDOT:PSS to form microelectrodes on such substrates has been challenging. Here we demonstrate a technique for the precise micropatterning of a conductive ink on ITO using photolithography to realize a covalently-attached ion-transport matrix for stable biosensing. This micropatterning is accomplished using an all water-based and ambient temperature processing. We present electrochemical characterization of the material composite via electrochemical impedance spectroscopy, cyclic voltammetry and differential pulse voltammetry. A sensitive sensor is fabricated for the neurotransmitter dopamine, with a linear range from 1 to 50μM. The sensor signal is very stable under cyclic increase and decrease in the concentration of dopamine. This sensing can be achieved even in the presence of ascorbic acid at 1000 times higher concentration than dopamine. Further, enzymes can be immobilized in the conductive matrix to form highly selective sensors. Such robust micropatterning strategies can greatly expand the use of conducting polymer substrates in biosensing applications.
RATIONALE:The peptide ligand apelin and its receptor APJ constitute a signaling pathway with numerous effects on the cardiovascular system, including cardiovascular development in model organisms ...such as xenopus and zebrafish.
OBJECTIVE:This study aimed to characterize the embryonic lethal phenotype of the Apj mice and to define the involved downstream signaling targets.
METHODS AND RESULTS:We report the first characterization of the embryonic lethality of the Apj mice. More than half of the expected Apj embryos died in utero because of cardiovascular developmental defects. Those succumbing to early embryonic death had markedly deformed vasculature of the yolk sac and the embryo, as well as poorly looped hearts with aberrantly formed right ventricles and defective atrioventricular cushion formation. Apj embryos surviving to later stages demonstrated incomplete vascular maturation because of a deficiency of vascular smooth muscle cells and impaired myocardial trabeculation and ventricular wall development. The molecular mechanism implicates a novel, noncanonical signaling pathway downstream of apelin-APJ involving Gα13, which induces histone deacetylase (HDAC) 4 and HDAC5 phosphorylation and cytoplasmic translocation, resulting in activation of myocyte enhancer factor 2. Apj mice have greater endocardial Hdac4 and Hdac5 nuclear localization and reduced expression of the myocyte enhancer factor 2 (MEF2) transcriptional target Krüppel-like factor 2. We identify a number of commonly shared transcriptional targets among apelin-APJ, Gα13, and MEF2 in endothelial cells, which are significantly decreased in the Apj embryos and endothelial cells.
CONCLUSIONS:Our results demonstrate a novel role for apelin-APJ signaling as a potent regulator of endothelial MEF2 function in the developing cardiovascular system.
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