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The release of chemicals following either pulsatile or continuous release modes is important for various potential applications, including programmed chemical reactions, mechanical actuation, and treatments of various diseases. However, the simultaneous application of both modes in a single material system has been challenging. Here, two chemical loading methods are reported in a liquid-crystal-infused porous surface (LCIPS) that enables both a pulsatile and continuous release of chemicals simultaneously. Specifically, chemicals loaded in the porous substrate exhibit a liquid crystal (LC) mesophase-dependent continuous release, whereas the chemicals dissolved in micrometer-sized aqueous droplets dispersed in the LC surface follow a pulsatile release activated by a phase transition. Moreover, the loading method of distinct molecules can be controlled to program their release mode. Finally, the pulsatile and continuous release of two distinct bioactive small molecules, tetracycline and dexamethasone, are demonstrated which display antibacterial and immunomodulatory activities for applications such as chronic wound healing and biomedical implant coating.

Effective hemorrhage control is indispensable for life-threatening emergencies in defense fields and civilian trauma. During major injuries, hemostatic agents are applied externally to mimic and accelerate the natural hemostasis process. Commercially available topical hemostatic agents are associated with several limitations

The utility of plant tissues as scaffolding materials has been gaining significant interest in recent years owing to their unique material characteristics that are ideal for tissue regeneration. In this study, the degradation and biocompatibility of natural cellulosic scaffolds derived from

The 2,4,5-tris(2-pyridyl)imidazole (L) molecule has been evaluated as a probe for dual sensing of Hg

Cardiovascular disease is the leading cause of death worldwide, often associated with coronary artery occlusion. A common intervention for arterial blockage utilizes a vascular graft to bypass the diseased artery and restore downstream blood flow; however, current clinical options exhibit high long-term failure rates. Our goal was to develop an off-the-shelf tissue-engineered vascular graft capable of delivering a biological payload based on the monocyte recruitment factor C-C motif chemokine ligand 2 (CCL2) to induce remodeling. Bi-layered silk scaffolds consisting of an inner porous and outer electrospun layer were fabricated using a custom blend of Antherea Assama and Bombyx Mori silk (lyogel). Lyogel silk scaffolds alone (LG), and lyogel silk scaffolds containing microparticles (LGMP) were tested. The microparticles (MPs) were loaded with either CCL2 (LGMP+) or water (LGMP-). Scaffolds were implanted as abdominal aortic interposition grafts in Lewis rats for 1 and 8 weeks. 1-week implants exhibited patency rates of 50% (7/14), 100% (10/10), and 100% (5/5) in the LGMP-, LGMP+, and LG groups, respectively. The significantly higher patency rate for the LGMP+ group compared to the LGMP- group (p = 0.0188) suggests that CCL2 can prevent acute occlusion. Immunostaining of the explants revealed a significantly higher density of macrophages (CD68+ cells) within the outer vs. inner layer of LGMP- and LGMP+ constructs but not in LG constructs. After 8 weeks, there were no significant differences in patency rates between groups. All patent scaffolds at 8 weeks showed signs of remodeling; however, stenosis was observed within the majority of explants. This study demonstrated the successful fabrication of a custom blended silk scaffold functionalized with cell-mimicking microparticles to facilitate controlled delivery of a biological payload improving their in vivo performance. Statement of significance This study outlines the development of a custom blended silk-based tissue–engineered vascular graft (TEVG) for use in arterial bypass or replacement surgery. A custom mixture of silk was formulated to improve biocompatibility and cellular binding to the tubular scaffold. Many current approaches to TEVGs include cells that encourage graft cellularization and remodeling; however, our technology incorporates a microparticle based delivery platform capable of delivering bioactive molecules that can mimic the function of seeded cells. In this study, we load the TEVGs with microparticles containing a monocyte attractant and demonstrate improved performance in terms of unobstructed blood flow versus blank microparticles. The acellular nature of this technology potentially reduces risk, increases reproducibility, and results in a more cost-effective graft when compared to cell-based options.

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 in vitro was uncovered using immunofluorescent staining and gene expression studies. Furthermore, in vivo 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.

Vascular tissue engineering is a rapidly growing field of regenerative medicine, which strives to find innovative solutions for vascular reconstruction. Considering the limited success of synthetic grafts, research impetus in the field is now shifted towards finding biologically active vascular substitutes bestowing in situ growth potential. In this regard, silk biomaterials have shown remarkable potential owing to their favorable inherent biological and mechanical properties. This review provides a comprehensive overview of the progressive development of silk-based small diameter (6 mm) tissue-engineered vascular grafts (TEVGs), emphasizing their pre-clinical implications. Herein, we first discuss the molecular structure of various mulberry and non-mulberry silkworm silk and identify their favorable properties at the onset of vascular regeneration. The emergence of various state-of-the-art fabrication methodologies for the advancement of silk TEVGs is rationally appraised in terms of their in vivo performance considering the following parameters: ease of handling, long-term patency, resistance to acute thrombosis, stenosis and aneurysm formation, immune reaction, neo-tissue formation, and overall remodeling. Finally, we provide an update on the pre-clinical status of silk-based TEVGs, followed by current challenges and future prospects. STATEMENT OF SIGNIFICANCE: Limited availability of healthy autologous blood vessels to replace their diseased counterpart is concerning and demands other artificial substitutes. Currently available synthetic grafts are not suitable for small diameter blood vessels owing to frequent blockage. Tissue-engineered biological grafts tend to integrate well with the native tissue via remodeling and have lately witnessed remarkable success. Silk fibroin is a natural biomaterial, which has long been used as medical sutures. This review aims to identify several favorable properties of silk enabling vascular regeneration. Furthermore, various methodologies to fabricate tubular grafts are discussed and highlight their performance in animal models. An overview of our understanding to rationally improve the biological activity fostering the clinical success of silk-based grafts is finally discussed.

Millions of people around the globe are affected by full-thickness skin injuries. A delay in the healing of such injuries can lead to the formation of chronic wounds, posing several clinical and economic challenges. Current strategies for wound care aim for skin regeneration and not merely skin repair or faster wound closure. The present study aimed to develop a bioactive wound-healing matrix comprising natural biomaterial silk fibroin (SF), clinical-grade human fibrin (FIB), and human hyaluronic acid (HA), resulting in SFFIBHA for regeneration of full-thickness burn wounds. A porous, hemostatic, self-adhesive, moisture-retentive, and biomimetic scaffold that promotes healing was the expected outcome. The study validated a terminal sterilization method, suggesting the stability and translational potential of the novel scaffold. Also, the study demonstrated the regenerative abilities of scaffolds using

A single system capable of delivering anticancer drugs and growth factors by a minimally invasive approach is in demand for effective treatment of triple-negative breast cancer (TNBC) after lumpectomy. Here, we showcase one such holistic system for TNBC therapy and its assessment via 3D in vitro lumpectomy model, a first of its kind. Firstly, Bombyx mori silk fibroin (BMSF) and Antheraea assamensis silk fibroin (AASF) blended hydrogels were prepared and biophysically characterized. Secondly, a 3D in vitro lumpectomy model was developed using MDA-MB-231 cell line to assess the efficacy of localized delivery of doxorubicin (dox) using injectable hydrogel system in terminating remaining breast cancer after lumpectomy. Additionally, we have also evaluated the adipose tissue regeneration in the lumpectomy region by delivering dexamethasone (dex) using injectable hydrogels. Rheological studies showed that the BMSF/AASF blended hydrogels exhibit viscoelasticity and injectability conducive for minimally invasive application. The developed hydrogels by virtue of its slow and sustained release of dox exerted cytotoxicity towards MDA-MB-231 cells assessed through in vitro studies. Further, dex loaded hydrogel supported adipogenic differentiation of adipose tissue derived stem cells (ADSCs), while the secreted factors were found to aid in vascularization and macrophage polarization. This was confirmed through in vitro angiogenic tube formation assay and macrophage polarization study respectively. The corroborated results vouch for potential application of this injectable hydrogels for localized anticancer drug delivery and aiding in breast reconstruction, post lumpectomy.

Silk fibroin and silk microfibers, both derived from silk cocoon, have been widely used for prospective biomedical, energy, and environmental applications. However, various complex and catalyst-based approaches have been adopted for chemical modification and integration of different functionalities in silk fibroin-based materials. Here, both tailored water wettability and mechanical property have been associated with silk microfiber reinforced silk fibroin sponges (SMFRSFSs) through the strategic introduction of β-sheets and a facile and catalyst-free chemical reaction at ambient conditions. While the controlled tailoring of β-sheets in the silk fibroin skeletal framework of the sponges allowed us to modulate the compressive modulus, the 1,4-conjugate addition reaction between amine residues of silk (fiber and fibroin) and acrylate groups of a multifunctional cross-linker provided residual chemical reactivity. Further, the chemically "reactive" sponge was postmodified with the selected alkylamines to introduce a wide range of water wettability (from 36 to 161°) without affecting the mechanical property. Thereafter, the silk cocoon-derived and extremely water-repellent sponge was used for environment-friendly cleaning of oil spillages through selective absorption-based and filtration-based oil/water separation at different and severe aqueous conditions. This silk cocoon-derived mechanically tailorable and chemically reactive sponge could also be useful for various biomedical and energy-related applications.

Hypothesis Modeling three-dimensional (3D) in vitro culture systems recapitulating spatiotemporal characteristics of native tumor-mass has shown tremendous potential as a pre-clinical tool for drug screening. However, their applications in clinical settings are still limited due to inappropriate recapitulation of tumor topography, culture instability, and poor durability of niche support. Experiments Here, we have fabricated a bio-active silk composite scaffold assimilating tunable silk from Bombyx mori and – arginine-glycine-aspartate (RGD) rich silk from Antheraea assama to provide a better 3D-matrix for breast (MCF 7) and liver (HepG2) tumoroids. Cellular mechanisms underlying physiological adaptations in 3D constructs and subsequent drug responses were compared with conventional monolayer and multicellular spheroid culture. Findings Silk composite matrix assists prolonged growth and high metabolic activity (Cytochrome P450 reductase) in breast and liver 3D-tumoroids. Enhanced stemness expression (Cell surface adhesion receptor; CD44, Aldehyde dehydrogenase 1) and epithelial-mesenchymal-transition markers (E-cadherin, Vimentin) at transcript and protein levels demonstrate that bio-active matrix-assisted 3D environment augmenting metastatic potential in tumoroids. Together, enhanced secretion of Transforming growth factor β (TGFβ), anchorage-independency, and colony-forming potential of cells in the 3D-tumoroids further corroborates the aggressive behavior of cells. Moreover, the multilayered 3D-tumoroids exhibit decreased sensitivity to some known anticancer drugs (Doxorubicin and Paclitaxel). In conclusion, the bio-active silk composite matrix offers an advantage in developing robust and sustainable 3D tumoroids for a high-throughput drug screening platform.

The synthesis and characterization of chiral pincer-ruthenium complexes of the type (R2NNN)RuCl2 (PPh3) (R = 3-methylbutyl and 3,3-dimethylbutyl) is reported here. The cytotoxicity studies of these complexes were studied and compared with the corresponding activity of achiral complexes. The cytotoxic effect of pincer-ruthenium complexes on human dermal fibroblasts and human tongue carcinoma cells assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay displayed an inhibition of normal and cancer cell growth in a dose-dependent manner. Intracellular reactive oxygen species (ROS) level measurement, lactate dehydrogenase assay, DNA fragmentation, and necrosis studies revealed that treatment with pincer-ruthenium complexes induced a redox imbalance in SAS cells by upregulating ROS generation and caused necrotic cell death by disrupting the cellular membrane integrity.

Control promotion and prevention of platelet adhesion are important for various biomedical applications. In the past, surface topography and chemical modifications have been commonly utilized for tailoring the promotion and prevention of platelet adhesion. Recently, lotus-leaf-inspired superhydrophobicity has appeared as an efficient avenue to prevent platelet adhesion. However, such extreme water repellent interfaces fail to perform upon prolonged and continuous exposure to aqueous phase. In this communication, the strategic use of a catalyst-free 1,4-conjugate addition reaction between amine and acrylate allowed us to investigate the impact of two distinct underwater oil-wettability on platelet adhesion activity. While underwater superoleophobicity inhibited platelet-adhesion, a highly aggregated fibrous network of adhered platelets was observed on underwater superoleophilic coating. Further, this biocompatible and haemocompatible underwater superoleophobic multilayer coating was deposited on a commercially available catheter tube to examine its potential towards the prevention of platelet attachment.

Bioengineering an in vitro liver model recapitulating the native liver microarchitecture consisting of parenchymal and non-parenchymal cells is crucial in achieving cellular crosstalk and hepatic metabolic functions for accurate hepatotoxicity prediction. Bioprinting holds the promise of engineering constructs with precise control over the spatial distribution of multiple cells. Two distinct tissue-specific liver extracellular matrix (ECM)-based bioinks with excellent printability and rheological attributes are formulated for supporting parenchymal and non-parenchymal cells. A physiologically relevant human vascularized liver model is bioprinted with a novel liver ECM-based bioink laden with human adipose mesenchymal stem cell-derived hepatocyte-like cells (HLCs), human umbilical vein endothelial cells (HUVECs), and human hepatic stellate cells (HHSCs) using an extrusion-based bioprinting approach and validated for hepatotoxicity assessment. The HLC/HUVEC/HHSC-laden liver model resembles native alternate cords of hepatocytes with a functional sinusoidal lumen-like network in both horizontal and vertical directions, demonstrating enhanced albumin production, urea synthesis, and cytochrome P450 (CPR) activity. Furthermore, the liver model is evaluated for drug toxicity assessment following 24 h exposure to different concentrations of (i) non-hepatotoxicants aspirin and dexamethasone, (ii) idiosyncratic hepatotoxicant trovafloxacin mesylate, and (iii) clinical hepatotoxicant acetaminophen and troglitazone. A follow-up cell viability and metabolic competence evaluation by estimating DNA concentration, lactate dehydrogenase activity, and CPR activity revealed a dose-dependent clinically relevant hepatotoxic response. These results corroborated that the developed clinically relevant vascularized liver model is affordable and would aid pharmaceutical companies in speeding up the drug development and provide a robust platform for hepatotoxicity screening.

DNA-based nanostructures have emerged as a versatile component for nanoscale construction of soft materials. Multiple structural, functional properties and versatility in conjugation with other biomolecules made DNA the material of choice to use in various biomedical applications. DNA-based hydrogels significantly attracted attention in recent years owing to their properties and applications in biosensing, bioimaging, and therapeutics. Here, we summarize the recent advances in the area of DNA hydrogels where these are used either as structural material or as functional entities to make hybrid constructs with various biomedical applications. Multiple synthetic routes for constructing DNA hydrogels are summarized first, where the structural motifs and spatial arrangements are considered for the classification of DNA materials. We then present the characterization and properties of DNA hydrogels using multiple imaging and biophysical techniques. Further, different biomedical applications of DNA hydrogels are presented such as biosensing, bioimaging, and targeted drug delivery and as scaffolds to program cellular systems. Last, we discuss the vision and potential of DNA based hydrogels as an emerging class of therapeutically important devices for theragnostic and other biological applications.

Localized cancer chemotherapy through injectable hydrogels is a next-generation advanced substitute for the currently operational systemic route of drug administration. Recently, several hydrogels have been developed for prospective drug delivery applications; however, no

Vascular tissue engineering is aimed at developing regenerative vascular grafts to restore tissue function by bypassing or replacing defective arterial segments with tubular biodegradable scaffolds. Scaffolds are often combined with stem or progenitor cells to prevent acute thrombosis and initiate scaffold remodeling. However, there are limitations to cell-based technologies regarding safety and clinical translation. Extracellular vesicles (EVs) are nanosized particles released by most cell types, including stem and progenitor cells, that serve to transmit protein and RNA cargo to target cells throughout the body. EVs have been shown to replicate the therapeutic effect of their parent cells; therefore, EVs derived from stem or progenitor cells may serve as a more translatable, cell-free, therapeutic base for vascular scaffolds. Our study aims to determine if EV incorporation provides a positive effect on graft patency and remodeling

The success of tissue-engineered vascular graft (TEVG) predominantly relies on the selection of a suitable biomaterial and graft design. Natural biopolymer silk has shown great promise for various tissue-engineering applications. This study is the first to investigate Indian endemic non-mulberry silk (Antheraea assama-AA) – which inherits naturally superior mechanical and biological traits (e.g., RGD motifs) compared to Bombyx mori-BM silk, for TEVG applications. We designed bi-layered biomimetic small diameter AA-BM silk TEVGs adopting a new fabrication methodology. The inner layer showed ideally sized (~40 µm) pores with interconnectivity to allow cellular infiltration, and an outer dense electrospun layer that confers mechanical resilience. Biodegradation of silk TEVGs into amino acids as resorbable byproducts corroborates their in vivo remodeling ability. Following our previous reports, we surgically implanted human adipose tissue-derived stromal vascular fraction (SVF) seeded silk TEVGs in Lewis rats as abdominal aortic interposition grafts for 8 weeks. Adequate suture retention strength (0.45 ± 0.1 N) without any blood seepage post-implantation substantiate the grafts’ viability. AA silk-based TEVGs showed superior animal survival and graft patency compared to BM silk TEVGs. Histological analysis revealed neo-tissue formation, host cell infiltration and graft remodeling in terms of extracellular matrix turnover. Altogether, this study demonstrates promising aspects of AA silk TEVGs for vascular tissue engineering applications. Statement of significance Clinical ‘off the shelf’ implementation of tissue-engineered vascular grafts (TEVGs) remains a challenge. Achieving optimal blood vessel regeneration requires the use of bioresorbable materials having suitable degradation rates while producing minimal or no toxic byproducts. Host cell recruitment and preventing acute thrombosis are other pre-requisites for successful graft remodeling. In this study, for the first time we explored the use of naturally derived Indian endemic non-mulberry Antheraea assama silk in combination with Bombyx mori silk for TEVG applications by adopting a new biomimetic approach. Our bi-layered silk TEVGs were optimally porous, mechanically resilient and biodegradable. In vivo implantation in rat aorta showed long-term patency and graft remodeling by host cell infiltration and extracellular matrix deposition corroborating their clinical feasibility.

Silk biomaterials are known for biomedical and tissue engineering applications including drug delivery and implantable devices owing to their biocompatible and a wide range of ideal physico-chemical properties. Herein, we present a critical overview of the progress of silk-based matrices in skin regeneration therapeutics with an emphasis on recent innovations and scientific findings. Beginning with a brief description of numerous varieties of silks, the review summarizes our current understanding of the biological properties of silk that help in the wound healing process. Various silk varieties such as silkworm silk fibroin, silk sericin, native spider silk and recombinant silk materials have been explored for cutaneous wound healing applications from the past few decades. With an aim to harness the regenerative properties of silk, numerous strategies have been applied to develop functional bioactive wound dressings and viable bio-artificial skin grafts in recent times. The review examines multiple inherent properties of silk that aid in the critical events of the healing process such as cell migration, cell proliferation, angiogenesis, and re-epithelialization. A detailed insight into the progress of silk-based cellular skin grafts is also provided that discusses various co-culture strategies and development of bilayer and tri-layer human skin equivalent under in vitro conditions. In addition, functionalized silk matrices loaded with bioactive molecules and antibacterial compounds are discussed, which have shown great potential in treating hard-to-heal wounds. Finally, clinical studies performed using silk-based translational products are reviewed that validate their regenerative properties and future applications in this area. STATEMENT OF SIGNIFICANCE: The review article discusses the recent advances in silk-based technologies for wound healing applications, covering various types of silk biomaterials and their properties suitable for wound repair and regeneration. The article demonstrates the progress of silk-based matrices with an update on the patented technologies and clinical advancements over the years. The rationale behind this review is to highlight numerous properties of silk biomaterials that aid in all the critical events of the wound healing process towards skin regeneration. Functionalization strategies to fabricate silk dressings containing bioactive molecules and antimicrobial compounds for drug delivery to the wound bed are discussed. In addition, a separate section describes the approaches taken to generate living human skin equivalent that have recently contributed in the field of skin tissue engineering.

Prodigious progress in the past decade has pronounced 3D printing as one of the most promising technique for assembling biological materials in a complex layout that mimics native human tissues. With the advent of technology, several improvements in printing techniques have facilitated the development of intricate strategies and designs that were imaginably distant due to the conventional top-down approaches. Most of these advanced strategies generally follow a thorough coordination and an elaborate biomimetic blueprint due to which it is now possible to fabricate

Silk, a natural biopolymer, has been used clinically as suture material over thousands of years and has received much impetus for a plethora of biomedical applications in the last two decades. Silk protein isolated from both mulberry and nonmulberry silkworm varieties gained recognition as a potential biomaterial owing to its affordability and remarkable physicochemical properties. Molecular studies on the amino acid composition and conformation of silk proteins interpreted in the present review provide a critical understanding of the difference in crystallinity, hydrophobicity, and tensile strength among silkworm silk proteins. Meticulous silk fibroin (SF) isolation procedures and innovative processing techniques to fabricate gamut of two-dimensional (2D) and three-dimensional (3D) matrices including the latest 3D printed scaffolds have led SF for diverse biomedical applications. Crucial factors for clinical success of any biomaterial, including biocompatibility, immune response, and biodegradability, are discussed with particular emphasis on the lesser-known endemic nonmulberry silk varieties, which in recent years have gained considerable attention. The tunable biodegradation and bioresorbable attributes of SF enabled its use in drug delivery systems, thus proving it as an efficient and specific vehicle for controlled drug release and targeted drug delivery. Advancements in fabrication methodologies inspired biomedical researchers to develop SF-based

Dysregulation of sequential and synchronized events of skin regeneration often results in the impairment of chronic wounds. Conventional wound dressings fail to trigger the normal healing mechanism owing to the pathophysiological conditions. Tissue engineering approaches that deal with the fabrication of dressings using various biomaterials, growth factors, and stem cells have shown accelerated healing outcomes. However, most of these technologies are associated with difficulties in scalability and cost-effectiveness of the products. In this review, we survey the latest developments in wound healing strategies that have recently emerged through the multidisciplinary approaches of bioengineering, nanotechnology, 3D bioprinting, and similar cutting-edge technologies to overcome the limitations of conventional therapies. We also focus on the potential of wearable technology that supports complete monitoring of the changes occurring in the wound microenvironment. In addition, we review the role of advanced devices that can precisely enable the delivery of nanotherapeutics, oligonucleotides, and external stimuli in a controlled manner. These technological advancements offer the opportunity to actively influence the regeneration process to benefit the treatment regime further. Finally, the clinical relevance, trajectory, and prospects of this field have been discussed in brief that highlights their potential in providing a beneficial wound care solution at an affordable cost.

Topical delivery of potential antioxidants protects the skin against ultraviolet (UV) radiation-induced oxidative damage through maintaining redox balance. Sericin, one of the major components of silk, possesses antioxidant property along with skin-protective activity against UVB radiation-induced damage. However, the protective activity of silk sericin (SS) extracted from different sources has not been explored against UVA and UVB radiation-induced oxidative damage. In the present study, we have systematically investigated the protective activity of sericin against UVA and UVB radiation-induced skin damage. MTT and neutral red assays showed that Philosamia ricini sericin (PRS) and Antheraea assamensis sericin (AAS) (10 μg/mL) treatment prior to UVA (12 J/cm2) and UVB (120 mJ/cm2) irradiations enhanced the viability of human keratinocytes. Examination of cell cycle arrest and apoptotic/necrotic cell death using flow cytometry showed that sericin treatment before UVA and UVB irradiation protected the cells...

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.

Postnatal fracture healing of atrophic long bone diaphyseal nonunions remains a challenge for orthopedic surgeons. Paucity of autologous spongiosa has potentiated the use of tissue engineered bone grafts to improve success rates of bone marrow engraftment used in plate reosteosynthesis. Herein, the development and in vitro validation of a "sandwich-type" biofabricated diaphyseal cross-sectional unit, with an outer mechanically robust bioprinted cortical bone shell, encompassing an engineered bone marrow, are reported. Channelized silk fibroin blend sponges derived from Bombyx mori and Antheraea assama help in developing compartmentalized endosteum, exhibiting specialized osteoblasts (endosteal niche) and discontinuous endothelium (vascular niche). The cellular cross-talk between these two niches triggered via integrin-mediated cell adhesion, enables in preserving quiescence state of CD34

Silk fibroin (SF) is a natural well-known biomaterial that has widely been explored for various tissue engineering applications with great success. Herein, we describe the methodology for fabricating two different types of tubular silk scaffolds aimed for vascular grafting. The first method emphasizes the use of very thin (10-15μm) silk films with unidirectional longitudinal micro-patterns, followed by their sequential rolling, which results in a multilayered tubular graft mimicking native-like cellular composition. The second method describes the fabrication of a bi-layered tubular scaffold comprising of a highly porous inner layer covered with an outer nanofibrous electrospun layer.

Silk fibroin (SF) is a natural well-known biomaterial that has widely been explored for various tissue engineering applications with great success. Herein, we describe the methodology for fabricating two different types of tubular silk scaffolds aimed for vascular grafting. The first method emphasizes the use of very thin (10-15μm) silk films with unidirectional longitudinal micro-patterns, followed by their sequential rolling, which results in a multilayered tubular graft mimicking native-like cellular composition. The second method describes the fabrication of a bi-layered tubular scaffold comprising of a highly porous inner layer covered with an outer nanofibrous electrospun layer.

Mimicking nativelike metabolic zonation is indispensable to develop an efficient bioartificial liver model, as it facilitates physiological cues, hepatocyte polarity, and phenotypic functions. The present study shows the first evidence of hepatocyte metabolic heterogeneity in an in vitro liver model encompassing liver extracellular matrix (ECM)-functionalized silk scaffolds (LECM-SF) by altering ECM proportion. Upon static culture, individual LECM-SF scaffold supports differential synthetic and metabolic functions of cultured primary neonatal rat hepatocytes (PNRHs), owing to discrete biophysical attributes. A single in vitro liver system comprising PNRHs seeded LECM-SF scaffolds assisting periportal to pericentral gradient functions is stacked and matured in a perfusion bioreactor to simulate oxygen gradient. The scaffold with high ECM supports periportal-specific albumin synthesis, urea secretion, and bile duct formation, albeit scaffold with low ECM supports pericentral-specific cytochrome P450 activity. Extensive physicochemical characterizations confirmed the stability and interconnected porous network of scaffolds, signifying cellular infiltration and bidirectional nutrient diffusion. Furthermore, scaffolds demonstrate minimal thrombogenicity, reduced foreign-body response, and enhanced pro-remodeling macrophage activation, supporting constructive tissue remodeling. The developed liver model with zone-specific functions would be a promising avenue in bioartificial liver and drug screening.

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 (via YAP/TAZ) in contrast to cardiomyocytes cultured on rGO-GelMA.

Urokinase plasminogen activator (uPA) has been extensively used as a thrombolytic drug in cases of myocardial infarction, thromboembolism, and ischemic brain stroke. Media optimization and high-density perfusion culture are the decisive factors that facilitate enhanced urokinase production in a conditioned medium. In this study, we have aimed for a high-density perfusion culture of HT1080, a human fibrosarcoma cell line, by formulating optimal media for enhanced urokinase productivity. Four scaffold variants were fabricated from silk fibroin and microfibers of Bombyx mori (BM) and Antheraea assamensis (AA) and physico-chemically characterized. Field emission scanning electron microscopy studies revealed a heterogeneous distribution of pores with interconnected networks supporting cell infiltration, attachment, and long-term viability. AA-based fiber-reinforced scaffolds (ASAF) demonstrated superior mechanical strength, integral stability, and increased cell proliferation as compared to pure silk scaffolds. Media formulation was accomplished by limiting serum concentration (2% FBS) and supplementing with 20 μg/mL arginine and 20 ng/mL TGF-β1 to retain the stationary phase of cells and augment the urokinase production. A perfusion bioreactor culture of HT1080-laden scaffolds in the presence of formulated media was performed for improving the production of urokinase, with a maximum activity of 432 U/L. Also, gene expression analysis revealed that the individual silk scaffolds have different effects on regulating the expression of plasminogen activator urokinase and plasminogen activator urokinase receptor. In brief, our results suggest that a perfusion bioreactor culture of HT1080-laden ASAF scaffolds in formulated media promotes an increased urokinase production, such that it can be further used as a novel 3D matrix platform for industrial production of the lifesaving uPA drug.

Substantial progress in biomaterial research over the years has culminated in revolutionary technological advancements in the healthcare domain. This has triggered the quest for affordable healthcare solutions with focus on sustainable biomaterials with versatile applications endowed with green fabrication strategies. Silk as a biopolymer has garnered special attention which can largely be attributed to the excellent material properties of silk in addition to its affordability and resource ability. Silk fibroin from various silkworm and spider species and sericin from various silkworm species have been researched for their potential applications in the healthcare industry such as tissue-engineered grafts, cancer therapeutics, high-throughput tissue-on-chip models, food preservatives, biomedical imaging, biosensing, biomedical textiles, implants, cosmetics and bioremediation products. The present review mainly focusses on the various sources of silk fibroin and its relevant properties that have been conferred to it by nature. Moreover, recent developments, progress and prevalent modalities of healthcare industry that involve the application of silk fibroin and sericin have been outlined in the present review.

In this study, the effect of cellular cross-talk on modulation of chondrogenesis and hypertrophy while minimizing the usage of articular chondrocytes (ACs) has been investigated. Herein, co-culture of ACs with adipose-derived human mesenchymal stem cells (ADhMSCs) was employed for cross-talk within silk fibroin (SF)-based three-dimensional (3D) scaffolds. The co-culture model was developed by co-culturing four different ratios of ADhMSCs to ACs: 1:0, 3:1, 1:1, and 0:1 on porous 3D SF scaffolds for 21 days. The co-culture groups were cultured in defined media without adding any exogenous growth factors except the monoculture group, ADhMSC-only controls. The co-cultured constructs indicated significantly higher cellular viability and proliferation than the control monoculture groups. The supernatants of co-culture groups indicated significantly higher levels of TGF-β1 and IL-10, which confirmed the production of the morphogens/signaling molecules by chondrocytes for induction of ADhMSCs differentiation toward the chondrogenic phenotype. Biochemical assays indicated enhanced accumulation of sulfated glycosaminoglycans, collagen, and high DNA content along with high cellularity in co-culture groups than chondrocyte-only controls. Co-culture groups revealed synergistic interactions between cells as indicated by the interaction index value ranging from 2-3. Furthermore, upregulation of putative chondrogenic markers-aggrecan, sox-9, and collagen II, and significantly reduced expression of hypertrophic genes-collagen type X and MMP-13 was revealed in co-culture constructs. Histological and immunohistochemical staining also demonstrated even distribution and deposition of ECM in co-cultured constructs. Taken together, this work presents the potential of the developed 3D co-culture model toward modulation of chondrogenesis and hypertrophy via 3D microenvironment induced by physicochemical and biological properties of SF scaffolds, synergistic interactions between cells, and paracrine signaling in the co-culture system.

Full-thickness cutaneous wounds, such as deep burns, are complex wounds that often require surgical interventions. Herein, we show the efficacy of acellular grafts that can be made available off-the-shelf at an affordable cost using silk biomaterials. Silkworm silk fibroin (SF), being a cost-effective and natural biopolymer, provides essential features required for the fabrication of three-dimensional constructs for wound-healing applications. We report the treatment of third-degree burn wounds using a freeze-dried microporous scaffold of Antheraea assama SF (AaSF) functionalized with a recombinant spider silk fusion protein FN-4RepCT (FN-4RC) that holds the fibronectin cell binding motif. In order to examine the healing efficiency of functionalized silk scaffolds, an in vivo burn rat model was used, and the scaffolds were implanted by a one-step grafting procedure. The aim of our work is to investigate the efficacy of the developed acellular silk grafts for treating full-thickness wounds as well as to examine the effect of recombinant spider silk coatings on the healing outcomes. Following 14-day treatment, AaSF scaffolds coated with FN-4RC demonstrated accelerated wound healing when compared to the uncoated counterpart, commercially used DuoDERM dressing patch, and untreated wounds. Histological assessments of wounds over time further confirmed that functionalized silk scaffolds promoted wound healing, showing vascularization and re-epithelialization in the initial phase. In addition, higher extent of tissue remodeling was affirmed by the gene expression study of collagen type I and type III, indicating advanced stage of healing by the silk treatments. Thus, the present study validates the potential of scaffolds of combined silkworm silk and FN-4RC for skin regeneration.

Complex cutaneous wounds like diabetic foot ulcers represent a critical clinical challenge and demand a large-scale and low-cost strategy for effective treatment. Herein, we use a rabbit animal model to investigate efficacy of bioactive wound dressings made up of silk biomaterials. Nanofibrous mats of Antheraea assama silkworm silk fibroin (AaSF) are coated with various recombinant spider silk fusion proteins through silk-silk interactions to fabricate multifunctional wound dressings. Two different types of spider silk coatings are used to compare their healing efficiency: FN-4RepCT (contains a cell binding motif derived from fibronectin) and Lac-4RepCT (contains a cationic antimicrobial peptide from lactoferricin). AaSF mats coated with spider silk show accelerated wound healing properties in comparison to the uncoated mats. Among the spider silk coated variants, dual coating of FN-4RepCT and Lac-4RepCT on top of AaSF mat demonstrated better wound healing efficiency, followed by FN-4RepCT and Lac-4RepCT single coated counterparts. The in vivo study also reveals excellent skin regeneration by the functionalized silk dressings in comparison to commercially used Duoderm dressing and untreated wounds. The spider silk coatings demonstrate early granulation tissue development, re-epithelialization, and efficient matrix remodelling of wounds. The results thus validate potential of bioactive silk matrices in faster repair of diabetic wounds.

Repair and regeneration of nasal and auricular cartilage thrust significant challenges in reconstructive surgery. The burgeoning clinical requirement is yet to endorse a satisfactory cartilage replacement matrix. In this regard, we have bioengineered cross-linked decellularized caprine conchal cartilage (DC) as biocompatible, durable, and nontoxic matrices. The DC matrices exhibited reduced DNA and sulfated glycosaminoglycan (sGAG) with a minimal effect on the collagen content. Further, histology and scanning electron micrographs revealed a significant loss of cellular bodies and the presence of a compact matrix consisting of intricate collagen fibers, when compared to unprocessed matrices. An

The major limitations of traditional methods of anticancer drug delivery include systemic distribution and frequent administration intravenously. To address these issues, in our present approach, we have fabricated a nano hybrid silk hydrogel system for localized, targeted, and on-demand delivery of anticancer drugs. The hybrid system contains a blend of two varieties of silk protein and doxorubicin (DOX)-loaded folic acid functionalized single-walled carbon nanotubes (SWCNT-FA/DOX). Owing to the single-walled carbon nanotube (SWCNT) incorporation, the mechanical strength of the hybrid silk hydrogel composite enhanced significantly. A slow and sustained DOX release was recorded over a 14 day study. The amount of DOX released was determined by concentration of the SWCNT-FA/DOX payload, rate of silk degradation, pH of the released medium, and incubation temperature. The intermittent exposure of near-infrared light to the hybrid gel system stimulated on-demand DOX release. The

Catalyst-free and readily chemically reactive functional coatings that have immense prospects in various relevant applications are unprecedentedly synthesized directly using naturally existing bovi...

Prodigious progress in the past decade has pronounced 3D printing as one of the most promising technique for assembling biological materials in a complex layout that mimics native human tissues. Wi...

Cell instructive scaffolding platforms displaying synergistic effects by virtue of their chemical and physical cues have tremendous scope in modulating cell phenotype and thus improving the success of any graft. In this regard, we report here the development of Si- and Zn-doped brushite cement composited with silk scaffolding that hierarchically emulated the cancellous bone. The composite scaffolds fabricated exhibited an open porous network capable of enhanced osteoblast survival as attested by increased alkaline phosphatase activity and also sustaining osteoclast activity affirmed by tartrate resistant acid phosphatase staining. Moreover, the chemical cues presented by dissolutions products from the composite scaffold enabled the osteoblasts to secrete proangiogenic factors which favored better endothelial cell survival, confirmed through in vitro experiments. Moreover, the efficacy of these composite biomimetic scaffolds was validated in vivo in volumetric femur defects in rabbits, which revealed that these matrices influenced vascular cell infiltration and favored the formation of matured bony plate. Fluorochrome labeling studies and microtomography analysis revealed that at the end of three months, the implanted composite scaffolds had completely resorbed, leaving behind neo-osseous tissue and vouching for clinical translation of these composite matrices as viable and affordable bone-graft substitutes.