A bioprinted cardiac patch composed of cardiac-specific extracellular matrix and progenitor cells for heart repair

Congenital heart defects are present in 8 of 1000 newborns and palliative surgical therapy has increased survival. Despite improved outcomes, many children develop reduced cardiac function and heart failure requiring transplantation. Human cardiac progenitor cell (hCPC) therapy has potential to repair the pediatric myocardium through release of reparative factors, but therapy suffers from limited hCPC retention and functionality. Decellularized cardiac extracellular matrix hydrogel (cECM) improves heart function in animals, and human trials are ongoing. In the present study, a 3D-bioprinted patch containing cECM for delivery of pediatric hCPCs is developed. Cardiac patches are printed with bioinks composed of cECM, hCPCs, and gelatin methacrylate (GelMA). GelMA-cECM bioinks print uniformly with a homogeneous distribution of cECM and hCPCs. hCPCs maintain >75% viability and incorporation of cECM within patches results in a 30-fold increase in cardiogenic gene expression of hCPCs compared to hCPCs grown in pure GelMA patches. Conditioned media from GelMA-cECM patches show increased angiogenic potential (>2-fold) over GelMA alone, as seen by improved endothelial cell tube formation. Finally, patches are retained on rat hearts and show vascularization over 14 d in vivo. This work shows the successful bioprinting and implementation of cECM-hCPC patches for potential use in repairing damaged myocardium

Case studies on lithography-friendly vlsi circuit layout

Moore’s Law has driven a continuous demand for decreasing feature sizes used in Very Large Scale Integrated (VLSI) technology which has outpaced the solutions offered by lithography hardware. Currently, a light wavelength of 193nm is being used to print sub-65nm features. This introduces process variations which cause mismatches between desired and actual wafer feature sizes. However, the layout which affects the printability of a circuit can be modified in a manner which can make it more lithography-friendly. In this work, we intend to implement these modifications as a series of perturbations on the initial layout generated by the CAD tool for the circuit. To implement these changes we first calculate the feature variations offline on the boundaries of all possible standard cell pairs used in the circuit layout and record them in a Look-Up Table (LUT). After the CAD tool generates the initial placement of the circuit, we use the LUT to estimate the variations on the boundaries of all the standard cells. Depending on the features which may have the highest feature variations we assign a cost to the layout and our aim is now to reduce the cost of the layout after implementing perturbations which could be a simple cell flip or swap with a neighboring cell. The algorithm used to generate a circuit placement with a low cost is Simulated Annealing which allows a high probability for a solution with a higher cost to be selected during the initial iterations and as time goes on it tends closer to the greedy algorithm. The idea here is to avoid a locally optimum solution. It is also essential to minimize the impact of the iterations performed on the initial solution in terms of wirelength, vias and routing congestion. We validate our procedure on ISCAS85 benchmark circuits by simulating dose and defocus variations using the Mentor tool Calibre LFD. We obtain a reduction of greater 20% in the number of instances with the highest cell boundary feature variations. The wirelength and the number of vias showed an increase of roughly 2.2-8.8% and 1.2- 7.8% respectively for different circuits. The routing congestion by and large remains unaffected

High-Performance Screen-Printed Thermoelectric Films on Fabrics.

Printing techniques could offer a scalable approach to fabricate thermoelectric (TE) devices on flexible substrates for power generation used in wearable devices and personalized thermo-regulation. However, typical printing processes need a large concentration of binder additives, which often render a detrimental effect on electrical transport of the printed TE layers. Here, we report scalable screen-printing of TE layers on flexible fiber glass fabrics, by rationally optimizing the printing inks consisting of TE particles (p-type Bi0.5Sb1.5Te3 or n-type Bi2Te2.7Se0.3), binders, and organic solvents. We identified a suitable binder additive, methyl cellulose, which offers suitable viscosity for printability at a very small concentration (0.45-0.60 wt.%), thus minimizing its negative impact on electrical transport. Following printing, the binders were subsequently burnt off via sintering and hot pressing. We found that the nanoscale defects left behind after the binder burnt off became effective phonon scattering centers, leading to low lattice thermal conductivity in the printed n-type material. With the high electrical conductivity and low thermal conductivity, the screen-printed TE layers showed high room-temperature ZT values of 0.65 and 0.81 for p-type and n-type, respectively

Hedysarum coronarium-Based Green Composites Prepared by Compression Molding and Fused Deposition Modeling

In this work, an innovative green composite was produced by adding Hedysarum coronarium (HC) flour to a starch-based biodegradable polymer (Mater-Bi\uae, MB). The flour was obtained by grinding together stems, leaves and flowers and subsequently sieving it, selecting a fraction from 75 \ub5m to 300 \ub5m. Four formulations have been produced by compression molding (CM) and fused deposition modeling (FDM) by adding 5%, 10%, 15% and 20% of HC to MB. The influence of filler content on the processability was tested, and rheological, morphological and mechanical properties of composites were also assessed. Through CM, it was possible to obtain easily homogeneous samples with all filler amounts. Concerning FDM, 5% and 10% HC-filled composites proved also easily printable. Mechanical results showed filler effectively acted as reinforcement: Young\u2019s modulus and tensile strengths of the composites increased from 74.3 MPa to 236 MPa and from 18.6 MPa to 33.4 MPa, respectively, when 20% of HC was added to the pure matrix. FDM samples, moreover, showed higher mechanical properties if compared with CM ones due to rectilinear infill and fibers orientation. In fact, regarding the 10% HC composites, Young\u2019s modulus of the CM and FDM ones displayed a relative increment of 176% and 224%, respectively

The Use of Nanomaterials in Tissue Engineering for Cartilage Regeneration; Current Approaches and Future Perspectives

The repair and regeneration of articular cartilage represent important challenges for orthopedic investigators and surgeons worldwide due to its avascular, aneural structure, cellular arrangement, and dense extracellular structure. Although abundant efforts have been paid to provide tissue-engineered grafts, the use of therapeutically cell-based options for repairing cartilage remains unsolved in the clinic. Merging a clinical perspective with recent progress in nanotechnology can be helpful for developing efficient cartilage replacements. Nanomaterials, < 100 nm structural elements, can control different properties of materials by collecting them at nanometric sizes. The integration of nanomaterials holds promise in developing scaffolds that better simulate the extracellular matrix (ECM) environment of cartilage to enhance the interaction of scaffold with the cells and improve the functionality of the engineered-tissue construct. This technology not only can be used for the healing of focal defects but can also be used for extensive osteoarthritic degenerative alterations in the joint. In this review paper, we will emphasize the recent investigations of articular cartilage repair/regeneration via biomaterials. Also, the application of novel technologies and materials is discussed

Biofabrication for osteochondral tissue regeneration: bioink printability requirements

This work was funded by PAMI (ROTEIRO/0328/2013; Nº 022158), a Research Infrastructure of the National Roadmap of Research Infrastructures of Strategic Relevance for 2014–2020, co-funded by the FCT and European Union through the Centro2020.Biofabrication allows the formation of 3D scaffolds through a precise spatial control. This is of foremost importance when aiming to mimic heterogeneous and anisotropic architecture, such as that of the osteochondral tissue. Osteochondral defects are a supreme challenge for tissue engineering due to the compositional and structural complexity of stratified architecture and contrasting biomechanical properties of the cartilage-bone interface. This review highlights the advancements and retreats witnessed by using developed bioinks for tissue regeneration, taking osteochondral tissue as a challenging example. Methods, materials and requirements for bioprinting were discussed, highlighting the pre and post-processing factors that researchers should consider towards the development of a clinical treatment.info:eu-repo/semantics/publishedVersio

Bioactive Inks Development for Osteochondral Tissue Engineering: A Mini-Review

Nowadays, a prevalent joint disease affecting both cartilage and subchondral bone is osteoarthritis. Osteochondral tissue, a complex tissue unit, exhibited limited self-renewal potential. Furthermore, its gradient properties, including mechanical property, bio-compositions, and cellular behaviors, present a challenge in repairing and regenerating damaged osteochondral tissues. Here, tissue engineering and translational medicine development using bioprinting technology provided a promising strategy for osteochondral tissue repair. In this regard, personalized stratified scaffolds, which play an influential role in osteochondral regeneration, can provide potential treatment options in early-stage osteoarthritis to delay or avoid the use of joint replacements. Accordingly, bioactive scaffolds with possible integration with surrounding tissue and controlling inflammatory responses have promising future tissue engineering perspectives. This minireview focuses on introducing biologically active inks for bioprinting the hierarchical scaffolds, containing growth factors and bioactive materials for 3D printing of regenerative osteochondral substitutes

CRISPR/Cas9 system and fluorescence enhanced BA-LIFT bioprinting technique as a toolbox for the study of the Immune System

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Biología Molecular. Fecha de lectura: 24-09-2020In this work, the CRISPR/Cas system genome editing toolbox and the fluorescence enhanced BA-LIFT laser bioprinting tools have been used to study the immune system cells behavior. CD69 is tightly regulated at the transcription level by the CNS2 regulatory region, whose epigenetic marks define as a bivalent regulatory element that match with the previously definition of CD69 as a bivalent gene. By CRISPR/Cas9 transcriptional assays and genome editing, two major areas within the CNS2 enhancer with antagonistic but complementary regulatory activities in vivo were defined in T cells: a Core E region of ~60 bp with a dual repressor and activator function; and a 5’ region adjacent to the Core E (5’C) of ~160 bp where the major activation transcriptional machinery is associated. Deletion of the Core E led to a CD69 overexpression both at resting and after stimulation, supporting its repressive role at steady state and avoiding CD69 overexpression upon stimulation. The Core E is enriched in the Oct1 and Chd4 TFs, whose bivalent function have been previously defined. RNA-seq analysis of ΔCore E T cells showed that CD69 overexpression is associated with an increase of the chemokine receptors CCR1, CCR2 and CCR5 at steady state, and of its ligands CCL3L3, CCL4 and CCL4L1 after stimulation, highlighting the role of CD69 in the regulation of chemokines and its receptors, as has been previously observed in mouse models. The role of the human ERAP2 aminopeptidase in the antigen presentation was assessed by generating a functional ERAP2 KO in B cells. Comparison of the HLA-B*27:05 ligandomes of ERAP+/+ and ERAP-/- cells determine that ERAP2 destroy ligands with N-terminal basic residues and peptides with minority anchor motifs at P2 (K and Q). A compensation effect in other peptide positions was observed, since the overall stability of the peptides remained constant. A newly developed fluorescence enhanced BA-LIFT laser bioprinting technique has been integrated. A laser-based bioprinting device for accurate identification, selection and printing of single or grouped cells within a complex population was developed and validated. FE BA-LIFT has proven to be an efficient and precise tool with high viability and resolution when depositing biological material in hydrogels or scaffolds with different characteristics. An IFN-γ human NK cell reporter has been generated by CRISPR/Cas9 to be used for the validation of the FE BA-LIFT bioprinte

Make it greener: Exploring novel biobased materials in photopolymerization processes

L'abstract è presente nell'allegato / the abstract is in the attachmen