Bioprinting holds great promise toward engineering functional cardiac tissue constructs for regenerative medicine and as drug test models. However, it is highly limited by the choice of inks that ...require maintaining a balance between the structure and functional properties associated with the cardiac tissue. In this regard, a novel and mechanically robust biomaterial‐ink based on nonmulberry silk fibroin protein is developed. The silk‐based ink demonstrates suitable mechanical properties required in terms of elasticity and stiffness (≈40 kPa) for developing clinically relevant cardiac tissue constructs. The ink allows the fabrication of stable anisotropic scaffolds using a dual crosslinking method, which are able to support formation of aligned sarcomeres, high expression of gap junction proteins as connexin‐43, and maintain synchronously beating of cardiomyocytes. The printed constructs are found to be nonimmunogenic in vitro and in vivo. Furthermore, delving into an innovative method for fabricating a vascularized myocardial tissue‐on‐a‐chip, the silk‐based ink is used as supporting hydrogel for encapsulating human induced pluripotent stem cell derived cardiac spheroids (hiPSC‐CSs) and creating perfusable vascularized channels via an embedded bioprinting technique. The ability is confirmed of silk‐based supporting hydrogel toward maturation and viability of hiPSC‐CSs and endothelial cells, and for applications in evaluating drug toxicity.
In this work, a novel nonmulberry silk based biomaterial‐ink is reported for developing mechanically robust and clinically relevant cardiac patches. Both anisotropic avascular constructs for mimicking the native tissue structure, as well as vascularized constructs using an innovative embedded bioprinting technology are fabricated using the designed ink. The vascularized constructs along with a microfluidic system offer great potential for drug screening platforms.
Coronary artery disease is the most prevalent cardiovascular disease, claiming millions of lives annually around the world. The current treatment includes surgically inserting a tubular construct, ...called a stent, inside arteries to restore blood flow. However, due to lack of patient-specific design, the commercial products cannot be used with different vessel anatomies. In this review, we have summarized the drawbacks in existing commercial metal stents which face problems of restenosis and inflammatory responses, owing to the development of neointimal hyperplasia. Further, we have highlighted the fabrication of stents using biodegradable polymers, which can circumvent most of the existing limitations. In this regard, we elaborated on the utilization of new fabrication methodologies based on additive manufacturing such as three-dimensional printing to design patient-specific stents. Finally, we have discussed the functionalization of these stent surfaces with suitable bioactive molecules which can prove to enhance their properties in preventing thrombosis and better healing of injured blood vessel lining.
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•Diopside-lanthanum phosphate machinable ceramic composites fabricated successfully.•Weak Lanthanum phosphate interface aided in machining by hindering crack propagation.•The ...composites displayed compressive strength similar to native human cortical bone.•The composites displayed bioactive and osteoconductive properties.•The composites were machined by traditional tools to fabricate bone screws.
Bioceramic-based composites are extensively being used in orthopedics for decades due to their excellent biocompatibility and osteoconductivity. However, the inherent brittleness and high hardness of ceramics heavily impact their machinability, thus restricting their use as bone fixation devices. In this study, Mg-doped calcium silicate ceramic diopside (DI) has been employed as a ceramic matrix material owing to its superior mechanical properties in comparison to hydroxyapatite. To impart machinability in the diopside, rare earth lanthanum phosphate (LP) was introduced as a reinforcement. The indigenously synthesized and 800 °C calcined DI and LP powders were employed for composite fabrication by varying LP content (0–50% w/w). The composites were sintered at different temperatures (1000 °C, and 1200 °C) and sintering conditions (single sintered, and double sintered), and the 1200 °C double sintered (ds) composites were optimized due to their highest densification and mechanical properties. Among the optimized composites, ds-DI-LP (50:50, DL50) displayed the highest compressive strength (140 ± 5.21 MPa) compared to DL5 (121.16 ± 14.82 MPa) and DL10 (122.78 ± 28.74 MPa) composites. It was observed that the weak and layered LP interface in between the DI phase promoted machinability in the composites. Apart from being machinable, these ceramic composites were found to be bioactive, resulting in the formation of an apatite layer when immersed in simulated body fluid. Further, the optimized ceramic composites were found to be biocompatible and osteoconductive in nature on their functional assessment using primary rat calvarial osteoblast cells. Based on the results obtained, the ds-DL10 composites displayed considerable bioactivity and the highest ALP activity compared to ds-DL5 (p ≤ 0.01) and ds-DL50 (p ≤ 0.05) composites.
The phase separation of ceramics in a biopolymer matrix makes it challenging to achieve satisfactory mechanical properties required for orthopedic applications. It has been found that silane coupling ...agents can modify the surface of the bioceramic phase by forming a molecular bridge between the polymer and the ceramic, resulting in improved interfacial strength and adhesion. Therefore, in the present study, silane-modified diopside (DI) ceramic and ε-polycaprolactone (PCL) biopolymer composites were fabricated by injection molding method. The silane modification of DI resulted in their uniform dispersion in the PCL matrix, whereas agglomeration was found in composites containing unmodified DI. The thermal stability of the silane-modified DI-containing composites also increased. The Young's modulus of the composite containing 50% w/w DI modified by 3% w/w silane increased by 103% compared to composites containing 50% w/w unmodified DI. The biodegradation of the unmodified composites was significantly high, indicating their weak interfacial strength with the PCL matrix (
≤ 0.001). The osteoconductive behavior of the composites was also validated by in vitro cell-material studies. Overall, our findings supported that the silane-modified composites have improved surface roughness, mechanical, and osteoconductive properties compared to the unmodified composite and have the potential for orthopedic applications.
A hostile myocardial microenvironment post ischemic injury (myocardial infarction) plays a decisive role in determining the fate of tissue-engineered approaches. Therefore, engineering hybrid 3D ...printed platforms that can modulate the MI microenvironment for improving implant acceptance has surfaced as a critical requirement for reconstructing an infarcted heart. Here, we have employed a non-mulberry silk-based conductive bioink comprising carbon nanotubes (CNTs) to bioprint functional 3D vascularized anisotropic cardiac constructs. Immunofluorescence staining, polymerase chain reaction-based gene expression studies, and electrophysiological studies showed that the inclusion of CNTs in the bioink played a significant role in upregulating matured cardiac biomarkers, sarcomere formation, and beating rate while promoting cardiomyocyte viability. These constructs were then microinjected with calcium peroxide and IL-10-loaded gelatin methacryloyl microspheres. Measurements of oxygen concentration revealed that these microspheres upheld the oxygen availability for maintaining cellular viability for at least 5 days in a hypoxic environment. Also, the ability of microinjected IL-10 microspheres to modulate the macrophages to anti-inflammatory M2 phenotype
was uncovered using immunofluorescent staining and gene expression studies. Furthermore,
subcutaneous implantation of microsphere-injected 3D constructs provided insights toward the extended time frame that was achieved for dealing with the hostile microenvironment for promoting host neovascularization and implant acceptance.
Impairment of intestinal epithelium is a typical feature of inflammatory bowel disease (IBD) that causes leakage of bacteria and antigens from the intestinal lumen and thus results in persistent ...immune activation. Hence, healing and regeneration of the damaged gut mucosa is a promising therapeutic approach to achieve deep remission in IBD. Currently, available systemic therapies have moderate effects and are often associated with numerous side effects and malignancies. In this study, we aimed to develop a topical therapy by chemically conjugating a temperature-responsive polymer, i.e., poly(
-isopropylacrylamide), along with hyaluronic acid to obtain a sprayable therapeutic formulation that upon colon instillation adheres to the damaged gut mucosa due to its temperature-induced phase transition and mucoadhesive properties. An
adhesion experiment demonstrates that this therapeutic formulation forms a thin physical coating on the mucosal lining at a physiological temperature within 5 min. Physicochemical characterization of (P(NIPAM-
-NTBAM)-HA) established this formulation to be biocompatible, hemo-compatible, and non-immunogenic. Prednisolone was encapsulated within the polymer formulation to achieve maximum therapeutic efficacy in the case of IBD-like conditions as assessed in a custom-fabricated perfusion-based
model system. Histological analysis suggests that the prednisolone-encapsulated polymer formulation nearly restored the mucosal architecture after 2,4,6-trinitrobenzenesulfonic acid-induced damage. Furthermore, a significant (
≤ 0.001) increase in mRNA levels of Muc-2 and ZO-1 in treated groups further confirmed the mucosal epithelial barrier restoration.
Myocardial microenvironment plays a decisive role in guiding the function and fate of cardiomyocytes, and engineering this extracellular niche holds great promise for cardiac tissue regeneration. ...Platforms utilizing hybrid hydrogels containing various types of conductive nanoparticles have been a critical tool for constructing engineered cardiac tissues with outstanding mechanical integrity and improved electrophysiological properties. However, there has been no attempt to directly compare the efficacy of these hybrid hydrogels and decipher the mechanisms behind how these platforms differentially regulate cardiomyocyte behavior. Here, we employed gelatin methacryloyl (GelMA) hydrogels containing three different types of carbon-based nanoparticles: carbon nanotubes (CNTs), graphene oxide (GO), and reduced GO (rGO), to investigate the influence of these hybrid scaffolds on the structural organization and functionality of cardiomyocytes. Using immunofluorescent staining for assessing cellular organization and proliferation, we showed that electrically conductive scaffolds (CNT- and rGO-GelMA compared to relatively nonconductive GO-GelMA) played a significant role in promoting desirable morphology of cardiomyocytes and elevated the expression of functional cardiac markers, while maintaining their viability. Electrophysiological analysis revealed that these engineered cardiac tissues showed distinct cardiomyocyte phenotypes and different levels of maturity based on the substrate (CNT-GelMA: ventricular-like, GO-GelMA: atrial-like, and rGO-GelMA: ventricular/atrial mixed phenotypes). Through analysis of gene-expression patterns, we uncovered that the engineered cardiac tissues matured on CNT-GelMA and native cardiac tissues showed comparable expression levels of maturation markers. Furthermore, we demonstrated that engineered cardiac tissues matured on CNT-GelMA have increased functionality through integrin-mediated mechanotransduction (
YAP/TAZ) in contrast to cardiomyocytes cultured on rGO-GelMA.
Developing biomimetic cartilaginous tissues that support locomotion while maintaining chondrogenic behavior is a major challenge in the tissue engineering field. Specifically, while locomotive forces ...demand tissues with strong mechanical properties, chondrogenesis requires a soft microenvironment. To address this challenge, 3D cartilage‐like tissue is fabricated using two biomaterials with different mechanical properties: a hard biomaterial to reflect the macromechanical properties of native cartilage, and a soft biomaterial to create a chondrogenic microenvironment. To this end, a bath composed of an interpenetrating polymer network (IPN) of polyethylene glycol (PEG) and alginate hydrogel (MPa order compressive modulus) is developed as an extracellular matrix (ECM) with self‐healing properties. Within this bath supplemented with thrombin, human mesenchymal stem cell (hMSC) spheroids embedded in fibrinogen are 3D bioprinted, creating a soft microenvironment composed of fibrin (kPa order compressive modulus) that simulate cartilage's pericellular matrix and allow a fast diffusion of nutrients. The bioprinted hMSC spheroids present high viability and chondrogenic‐like behavior without adversely affecting the macromechanical properties of the tissue. Therefore, the ability to locally bioprint a soft and cell stimulating biomaterial inside of a mechanically robust hydrogel is demonstrated, thereby uncoupling the micro‐ and macromechanical properties of the 3D printed tissues such as cartilage.
In this work, 3D bioprinting technology is used to develop a biomimetic cartilage‐like tissue with near‐paradoxical mechanical properties, being soft at the cellular level, due to the soft bioink composed of human bone marrow mesenchymal stem cells in the form of spheroids embedded in fibrinogen, and the stiff polyethylene glycol and alginate bath, showing great potential for cartilage regeneration studies.
Cardiotoxicity is one of the most serious side effects of cancer chemotherapy. Current approaches to monitoring of chemotherapy‐induced cardiotoxicity (CIC) as well as model systems that develop in ...vivo or in vitro CIC platforms fail to notice early signs of CIC. Moreover, breast cancer (BC) patients with preexisting cardiac dysfunctions may lead to different incident levels of CIC. Here, a model is presented for investigating CIC where not only induced pluripotent stem cell (iPSC)‐derived cardiac tissues are interacted with BC tissues on a dual‐organ platform, but electrochemical immuno‐aptasensors can also monitor cell‐secreted multiple biomarkers. Fibrotic stages of iPSC‐derived cardiac tissues are promoted with a supplement of transforming growth factor‐β 1 to assess the differential functionality in healthy and fibrotic cardiac tissues after treatment with doxorubicin (DOX). The production trend of biomarkers evaluated by using the immuno‐aptasensors well‐matches the outcomes from conventional enzyme‐linked immunosorbent assay, demonstrating the accuracy of the authors’ sensing platform with much higher sensitivity and lower detection limits for early monitoring of CIC and BC progression. Furthermore, the versatility of this platform is demonstrated by applying a nanoparticle‐based DOX‐delivery system. The proposed platform would potentially help allow early detection and prediction of CIC in individual patients in the future.
In this paper, a cardiotoxicity‐on‐a‐chip platform containing induced pluripotent stem cell‐derived cardiac tissue communicating with breast cancer tissue is presented with electrochemical immuno‐aptasensors for non‐invasively monitoring cell secreted biomarkers. The suggested platform is capable of differentiating functionality and toxicity in healthy/fibrotic cardiac tissues after treatment with chemotherapy to step toward early detection and prediction of cardiotoxicity in individual patients.
In vitro cardiomyocyte (CM) maturation is an imperative step to replicate native heart tissue‐like structures as cardiac tissue grafts or as drug screening platforms. CMs are known to interpret ...biophysical cues such as stiffness, topography, external mechanical stimulation or dynamic perfusion load through mechanotransduction and change their behavior, organization, and maturation. In this regard, a silk‐based cardiac tissue (CT) coupled with a dynamic perfusion‐based mechanical stimulation platform (DMM) for achieving maturation and functionality in vitro is tried to be delivered. Silk fibroin (SF) is used to fabricate lamellar scaffolds to provide native tissue‐like anisotropic architecture and is found to be nonimmunogenic and biocompatible allowing cardiomyocyte attachment and growth in vitro. Further, the scaffolds display excellent mechanical properties by their ability to undergo cyclic compressions without any deformation when places in the DMM. Gradient compression strains (5% to 20%), mimicking the native physiological and pathological conditions, are applied to the cardiomyocyte culture seeded on lamellar silk scaffolds in the DMM. A strain‐dependent difference in cardiomyocyte maturation, gene expression, sarcomere elongation, and extracellular matrix formation is observed. These silk‐based CTs matured in the DMM can open up several avenues toward the development of host‐specific grafts and in vitro models for drug screening.
In this paper, lamellar silk scaffolds seeded with cardiomyocytes are used to develop a 3D cardiac tissue with patient‐like pathology and physiology by culturing them in a customized perfusion‐based dynamic mechanical microdevice. Silk scaffolds favor cardiomyocyte organization and maturation while the microdevice provides a native tissue‐like microenvironment in terms of mechanical strain as experienced by the healthy and fibrotic heart tissues.
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