Tissue spheroid fusion‐based in vitro screening assays for analysis of tissue maturation

Organ printing or computer‐aided robotic layer‐by‐layer additive biofabrication of thick three‐dimensional (3D) living tissue constructs employing self‐assembling tissue spheroids is a rapidly evolving alternative to classic solid scaffold‐based approaches in tissue engineering. However, the absence of effective methods of accelerated tissue maturation immediately after bioprinting is the main technological imperative and potential impediment for further progress in the development of this emerging organ printing technology. Identification of the optimal combination of factors and conditions that accelerate tissue maturation (‘maturogenic’ factors) is an essential and necessary endeavour. Screening of maturogenic factors would be most efficiently accomplished using high‐throughput quantitative in vitro tissue maturation assays. We have recently reviewed the formation of solid scaffold‐free tissue constructs through the fusion of bioprinted tissue spheroids that have measurable material properties. We hypothesize that the fusion kinetics of these tissue spheroids will provide an efficacious in vitro assay of the level of tissue maturation. We report here the results of experimental testing of two simple quantitative tissue spheroid fusion‐based in vitro high‐throughput screening assays of tissue maturation: (a) a tissue spheroid envelopment assay; and (b) a tissue spheroid fusion kinetics assay. Copyright © 2010 John Wiley & Sons, Ltd.     

An additive manufacturing‐based PCL–alginate–chondrocyte bioprinted scaffold for cartilage tissue engineering

Regenerative medicine is targeted to improve, restore or replace damaged tissues or organs using a combination of cells, materials and growth factors. Both tissue engineering and developmental biology currently deal with the process of tissue self‐assembly and extracellular matrix (ECM) deposition. In this investigation, additive manufacturing (AM) with a multihead deposition system (MHDS) was used to fabricate three‐dimensional (3D) cell‐printed scaffolds using layer‐by‐layer (LBL) deposition of polycaprolactone (PCL) and chondrocyte cell‐encapsulated alginate hydrogel. Appropriate cell dispensing conditions and optimum alginate concentrations for maintaining cell viability were determined. In vitro cell‐based biochemical assays were performed to determine glycosaminoglycans (GAGs), DNA and total collagen contents from different PCL–alginate gel constructs. PCL–alginate gels containing transforming growth factor‐β (TGFβ) showed higher ECM formation. The 3D cell‐printed scaffolds of PCL–alginate gel were implanted in the dorsal subcutaneous spaces of female nude mice. Histochemical [Alcian blue and haematoxylin and eosin (H&E) staining] and immunohistochemical (type II collagen) analyses of the retrieved implants after 4 weeks revealed enhanced cartilage tissue and type II collagen fibril formation in the PCL–alginate gel (+TGFβ) hybrid scaffold. In conclusion, we present an innovative cell‐printed scaffold for cartilage regeneration fabricated by an advanced bioprinting technology. Copyright © 2013 John Wiley & Sons, Ltd.     

Development of a synthetic tissue engineered three‐dimensional printed bioceramic‐based bone graft with homogenously distributed osteoblasts and mineralizing bone matrix in vitro

Over the last decade there have been increasing efforts to develop three‐dimensional (3D) scaffolds for bone tissue engineering from bioactive ceramics with 3D printing emerging as a promising technology. The overall objective of the present study was to generate a tissue engineered synthetic bone graft with homogenously distributed osteoblasts and mineralizing bone matrix in vitro, thereby mimicking the advantageous properties of autogenous bone grafts and facilitating usage for reconstructing segmental discontinuity defects in vivo. To this end, 3D scaffolds were developed from a silica‐containing calcium alkali orthophosphate, using, first, a replica technique – the Schwartzwalder–Somers method – and, second, 3D printing, (i.e. rapid prototyping). The mechanical and physical scaffold properties and their potential to facilitate homogenous colonization by osteogenic cells and extracellular bone matrix formation throughout the porous scaffold architecture were examined. Osteoblastic cells were dynamically cultured for 7 days on both scaffold types with two different concentrations of 1.5 and 3 × 10⁹ cells/l. The amount of cells and bone matrix formed and osteogenic marker expression were evaluated using hard tissue histology, immunohistochemical and histomorphometric analysis. 3D‐printed scaffolds (RPS) exhibited more micropores, greater compressive strength and silica release. RPS seeded with 3 × 10⁹ cells/l displayed greatest cell and extracellular matrix formation, mineralization and osteocalcin expression. In conclusion, RPS displayed superior mechanical and biological properties and facilitated generating a tissue engineered synthetic bone graft in vitro, which mimics the advantageous properties of autogenous bone grafts, by containing homogenously distributed terminally differentiated osteoblasts and mineralizing bone matrix and therefore is suitable for subsequent in vivo implantation for regenerating segmental discontinuity bone defects. Copyright © 2016 John Wiley & Sons, Ltd.     

Effect of implantation on engineered skeletal muscle constructs

The development of engineered skeletal muscle would provide a viable tissue for replacement and repair of muscle damaged by disease or injury. Our current tissue‐engineering methods result in three‐dimensional (3D) muscle constructs that generate tension but do not advance phenotypically beyond neonatal characteristics. To develop to an adult phenotype, innervation and vascularization of the construct must occur. In this study, 3D muscle constructs were implanted into the hindlimb of a rat, along the sciatic nerve, with the sural nerve isolated, transected and sutured to the construct to encourage innervation. Aortic ring anchors were sutured to the tendons of the biceps femoris muscle so that the construct would move dynamically with the endogenous muscle. After 1 week in vivo, the constructs were explanted, evaluated for force production and stained for muscle, nerve and collagen markers. Implanted muscle constructs showed a developing capillary system, an epimysium‐like outer layer of connective tissue and an increase in myofibre content. The beginning of α‐bungarotoxin clustering suggests that neuromuscular junctions (NMJs) could form on the implanted muscle, given more time in vivo. Additionally, the constructs increased maximum isometric force from 192 ± 41 μN to 549 ± 103 μN (245% increase) compared to in vitro controls, which increased from 276 ± 23 μN to 329 ± 27μN (25% increase). These findings suggest that engineered muscle tissue survives 1 week of implantation and begins to develop the necessary interfaces needed to advance the phenotype toward adult muscle. However, in terms of force production, the muscle constructs need longer implantation times to fully develop an adult phenotype. Copyright © 2012 John Wiley & Sons, Ltd.     

In situ handheld three‐dimensional bioprinting for cartilage regeneration

Articular cartilage injuries experienced at an early age can lead to the development of osteoarthritis later in life. In situ three‐dimensional (3D) printing is an exciting and innovative biofabrication technology that enables the surgeon to deliver tissue‐engineering techniques at the time and location of need. We have created a hand‐held 3D printing device (biopen) that allows the simultaneous coaxial extrusion of bioscaffold and cultured cells directly into the cartilage defect in vivo in a single‐session surgery. This pilot study assessed the ability of the biopen to repair a full‐thickness chondral defect and the early outcomes in cartilage regeneration, and compared these results with other treatments in a large animal model. A standardized critical‐sized full‐thickness chondral defect was created in the weight‐bearing surface of the lateral and medial condyles of both femurs of six sheep. Each defect was treated with one of the following treatments: (i) hand‐held in situ 3D printed bioscaffold using the biopen (HH group), (ii) preconstructed bench‐based printed bioscaffolds (BB group), (iii) microfractures (MF group) or (iv) untreated (control, C group). At 8 weeks after surgery, macroscopic, microscopic and biomechanical tests were performed. Surgical 3D bioprinting was performed in all animals without any intra‐ or postoperative complication. The HH biopen allowed early cartilage regeneration. The results of this study show that real‐time, in vivo bioprinting with cells and scaffold is a feasible means of delivering a regenerative medicine strategy in a large animal model to regenerate articular cartilage.     

Human chondrocyte migration behaviour to guide the development of engineered cartilage

Tissue‐engineering techniques have been successful in developing cartilage‐like tissues in vitro using cells from animal sources. The successful translation of these strategies to the clinic will likely require cell expansion to achieve sufficient cell numbers. Using a two‐dimensional (2D) cell migration assay to first identify the passage at which chondrocytes exhibited their greatest chondrogenic potential, the objective of this study was to determine a more optimal culture medium for developing three‐dimensional (3D) cartilage‐like tissues using human cells. We evaluated combinations of commonly used growth factors that have been shown to promote chondrogenic growth and development. Human articular chondrocytes (AC) from osteoarthritic (OA) joints were cultured in 3D environments, either in pellets or encapsulated in agarose. The effect of growth factor supplementation was dependent on the environment, such that matrix deposition differed between the two culture systems. ACs in pellet culture were more responsive to bone morphogenetic protein (BMP2) alone or combinations containing BMP2 (i.e. BMP2 with PDGF or FGF). However, engineered cartilage development within agarose was better for constructs cultured with TGFβ3. These results with agarose and pellet culture studies set the stage for the development of conditions appropriate for culturing 3D functional engineered cartilage for eventual use in human therapies. Copyright © 2015 John Wiley & Sons, Ltd.     

Collagen density gradient on three‐dimensional printed poly(ε‐caprolactone) scaffolds for interface tissue engineering

The ability to engineer scaffolds that resemble the transition between tissues would be beneficial to improve repair of complex organs, but has yet to be achieved. In order to mimic tissue organization, such constructs should present continuous gradients of geometry, stiffness and biochemical composition. Although the introduction of rapid prototyping or additive manufacturing techniques allows deposition of heterogeneous layers and shape control, the creation of surface chemical gradients has not been explored on three‐dimensional (3D) scaffolds obtained through fused deposition modelling technique. Thus, the goal of this study was to introduce a gradient functionalization method in which a poly(ε‐caprolactone) surface was first aminolysed and subsequently covered with collagen via carbodiimide reaction. The 2D constructs were characterized for their amine and collagen contents, wettability, surface topography and biofunctionality. Finally, chemical gradients were created in 3D printed scaffolds with controlled geometry and porosity. The combination of additive manufacturing and surface modification is a viable tool for the fabrication of 3D constructs with controlled structural and chemical gradients. These constructs can be employed for mimicking continuous tissue gradients for interface tissue engineering.     

Motility imaging via optical coherence phase microscopy enables label‐free monitoring of tissue growth and viability in 3D tissue‐engineering scaffolds

As the field of tissue engineering continues to progress, there is a deep need for non‐invasive, label‐free imaging technologies that can monitor tissue growth and health within thick three‐dimensional (3D) constructs. Amongst the many imaging modalities under investigation, optical coherence tomography (OCT) has emerged as a promising tool, enabling non‐destructive in situ characterization of scaffolds and engineered tissues. However, the lack of optical contrast between cells and scaffold materials using this technique remains a challenge. In this communication, we show that mapping the optical phase fluctuations resulting from cellular viability and motility allows for the distinction of live cells from their surrounding scaffold environment. Motility imaging was performed via a common‐path optical coherence phase microscope (OCPM), an OCT modality that has been shown to be sensitive to nanometer‐level fluctuations. More specifically, we examined the development of human adipose‐derived stem cells and/or murine pre‐osteoblasts within two distinct scaffold systems, commercially available alginate sponges and custom‐microfabricated poly(d , l ‐lactic‐co‐glycolic acid) fibrous scaffolds. Cellular motility is demonstrated as an endogenous source of contrast for OCPM, enabling real‐time, label‐free monitoring of 3D engineered tissue development. Copyright © 2013 John Wiley & Sons, Ltd.     

A review of key challenges of electrospun scaffolds for tissue‐engineering applications

Tissue engineering holds great promise to develop functional constructs resembling the structural organization of native tissues to improve or replace biological functions, with the ultimate goal of avoiding organ transplantation. In tissue engineering, cells are often seeded into artificial structures capable of supporting three‐dimensional (3D) tissue formation. An optimal scaffold for tissue‐engineering applications should mimic the mechanical and functional properties of the extracellular matrix (ECM) of those tissues to be regenerated. Amongst the various scaffolding techniques, electrospinning is an outstanding one which is capable of producing non‐woven fibrous structures with dimensional constituents similar to those of ECM fibres. In recent years, electrospinning has gained widespread interest as a potential tissue‐engineering scaffolding technique and has been discussed in detail in many studies. So why this review? Apart from their clear advantages and extensive use, electrospun scaffolds encounter some practical limitations, such as scarce cell infiltration and inadequate mechanical strength for load‐bearing applications. A number of solutions have been offered by different research groups to overcome the above‐mentioned limitations. In this review, we provide an overview of the limitations of electrospinning as a tissue‐engineered scaffolding technique, with emphasis on possible resolutions of those issues. Copyright © 2015 John Wiley & Sons, Ltd.     

Towards organ printing: engineering an intra-organ branched vascular tree

Importance of the field: Effective vascularization of thick three-dimensional engineered tissue constructs is a problem in tissue engineering. As in native organs, a tissue-engineered intra-organ vascular tree must be comprised of a network of hierarchically branched vascular segments. Despite this requirement, current tissue-engineering efforts are still focused predominantly on engineering either large-diameter macrovessels or microvascular networks.

Areas covered in this review: We present the emerging concept of organ printing or robotic additive biofabrication of an intra-organ branched vascular tree, based on the ability of vascular tissue spheroids to undergo self-assembly.

What the reader will gain: The feasibility and challenges of this robotic biofabrication approach to intra-organ vascularization for tissue engineering based on organ-printing technology using self-assembling vascular tissue spheroids including clinically relevantly vascular cell sources are analyzed.

Take home message: It is not possible to engineer 3D thick tissue or organ constructs without effective vascularization. An effective intra-organ vascular system cannot be built by the simple connection of large-diameter vessels and microvessels. Successful engineering of functional human organs suitable for surgical implantation will require concomitant engineering of a ‘built in’ intra-organ branched vascular system. Organ printing enables biofabrication of human organ constructs with a ‘built in’ intra-organ branched vascular tree.     

Hyaline cartilage next generation implants from adipose‐tissue–derived mesenchymal stem cells: Comparative study on 3D‐printed polycaprolactone scaffold patterns

We used additive manufacturing to fabricate 3D‐printed polycaprolactone scaffolds of different geometry topologies and porosities. We present a comparative analysis of hyaline cartilage development from adipose‐tissue–derived mesenchymal stem cells (ADMSCs) on three different, newly designed scaffold geometry patterns. The first scaffold design (MESO) was based on a rectilinear layer pattern. For the second pattern (RO45), we employed a 45° rotational layer loop. The design for the third scaffold (3DHC) was a three‐dimensional honeycomb‐like pattern with a hexagonal cellular distribution and small square shapes. We examined cell proliferation, colonization, and differentiation, in relation to the scaffold's structure, as well as to the mechanical properties of the final constructs. We gave emphasis on the scaffolds, both microarchitecture and macroarchitecture, for optimal and enhanced chondrogenic differentiation, as an important parameter, not well studied in the literature. Among the three patterns tested, RO45 was the most favourable for chondrogenic differentiation, whereas 3DHC better supported cell proliferation and scaffold penetration, exhibiting also the highest rate of increase onto the mechanical properties of the final construct. We conclude that by choosing the optimal scaffold architecture, the resulting properties of our cartilaginous constructs can better approximate those of the physiological cartilage.     

Cells for tissue engineering of cardiac valves

Heart valve tissue engineering is a promising alternative to prostheses for the replacement of diseased or damaged heart valves, because tissue‐engineered valves have the ability to remodel, regenerate and grow. To engineer heart valves, cells are harvested, seeded onto or into a three‐dimensional (3D) matrix platform to generate a tissue‐engineered construct in vitro, and then implanted into a patient's body. Successful engineering of heart valves requires a thorough understanding of the different types of cells that can be used to obtain the essential phenotypes that are expressed in native heart valves. This article reviews different cell types that have been used in heart valve engineering, cell sources for harvesting, phenotypic expression in constructs and suitability in heart valve tissue engineering. Natural and synthetic biomaterials that have been applied as scaffold systems or cell‐delivery platforms are discussed with each cell type. Copyright © 2015 John Wiley & Sons, Ltd.     

Using swept‐source optical coherence tomography to monitor the formation of neo‐epidermis in tissue‐engineered skin

There is an increasing need for a robust, simple to use, non‐invasive imaging technology to follow tissue‐engineered constructs as they develop. Our aim was to evaluate the use of swept‐source optical coherence tomography (SS‐OCT) to image tissue‐engineered skin as it developed over several weeks. Tissue‐engineered skin was produced using both de‐epithelialized acellular dermis (DED) and amorphous collagen gels. In both cases the epidermis could be readily distinguished from the neodermis, based on a comparison with standard destructive histology of samples. Constructs produced with DED showed more epidermal/dermal maturation than those produced using collagen. The development of tissue‐engineered skin based on DED was accurately monitored with SS‐OCT over 3 weeks and confirmed with conventional histology. Copyright © 2010 John Wiley & Sons, Ltd.     

Characterization of engineered tissue construct mechanical function by magnetic resonance imaging

Non‐invasive magnetic resonance imaging (MRI) is a technology that enables the characterization of multiple physical phenomena in living and engineered tissues. The mechanical function of engineered tissues is a primary endpoint for the successful regeneration of many biological tissues, such as articular cartilage, spine and heart. Here we demonstrate the application of MRI to characterize the mechanical function of engineered tissue. Phase contrast‐based methods were demonstrated to characterize detailed deformation fields throughout the interior of native and engineered tissue, using an articular cartilage defect model as a study system. MRI techniques revealed that strain fields varied non‐uniformly, depending on spatial position. Strains were highest in the tissue constructs compared to surrounding native cartilage. Tissue surface geometry corresponded to strain fields observed within the tissue interior near the surface. Strain fields were further evaluated with respect to the spatial variation in the concentration of glycosaminoglycans ([GAG]), critical proteoglycans in the extracellular matrix of cartilage, as determined by gadolinium‐enhanced imaging. [GAG] also varied non‐uniformly, depending on spatial position and was lowest in the tissue constructs compared to the surrounding cartilage. The use of multiple MRI techniques to assess tissue mechanical function provides complementary data and suggests that deformation is related to tissue geometry, underlying extracellular matrix constituents and the lack of tissue integration in the model system studied. Specialized and advanced MRI phase contrast‐based methods are valuable for the detailed characterization and evaluation of mechanical function of tissue‐engineered constructs. Copyright © 2009 John Wiley & Sons, Ltd.     

Fetal dermal fibroblasts exhibit enhanced growth and collagen production in two‐ and three‐dimensional culture in comparison to adult fibroblasts

The high morbidity of tendon injuries and the poor outcomes observed following repair or replacement have stimulated interest in regenerative approaches to treatment and, in particular, the use of cell‐based analogues as alternatives to autologous and allogeneic graft repair. Given the known regenerative properties of fetal tissues, the objective of this study was to assess the biological and mechanical properties of tissue‐engineered three‐dimensional (3D) composites seeded with fetal skin cells. Dermal fibroblasts were isolated from pregnant rats and their fetuses and characterized in monolayer culture and on 3D resorbable polyester scaffolds. To determine the differences between fetal and adult fibroblasts, DNA, total protein and types I and III collagen production were measured. In addition, morphology and mechanical properties of the 3D constructs were examined. In monolayer culture, fetal fibroblasts produced significantly more types I and III collagen and displayed serum‐independent growth, while adult fibroblasts elaborated less collagen and exhibited reduced cell spreading and attachment under low‐serum conditions. In 3D culture, fetal constructs appeared more developed based on gross examination, with significantly more total DNA, total protein and normalized type I collagen production compared to adult specimens. Finally, after 35 days, fetal fibroblast‐seeded constructs possessed superior mechanical properties compared to adult samples. Taken together, these findings indicate that fetal dermal fibroblasts may be an effective source of cells for fabricating tissue equivalents to regenerate injured tendons. Copyright © 2009 John Wiley & Sons, Ltd.     

The effect of wicking fibres in tissue‐engineered bone scaffolds

The major limitation of large tissue‐engineered constructs used for bone regeneration is the lack of vasculature and, therefore, lack of transport of essential nutrients, chemical factors and progenitor cells. Research approaches to improve the transport properties of large scaffolds focus on using angiogenic factors and vasculogenic cells to create new vasculature; however, the slow rate of vessel formation and reliance on vessel self‐assembly in these approaches is problematic. In this study, a novel approach has been proposed, using proprietary engineered ‘wicking’ fibres of non‐circular cross‐section that provide highly efficient transport for fluid and cells. The effect of wicking fibres on the movement of fluorescein isothiocyanate (FITC)‐conjugated protein in a three‐dimensional (3D) hydrogel system was analysed. The results indicated that the rate of diffusion of the fluorescent protein was greatly enhanced in hydrogels that contained wicking fibres in comparison to those that did not. The movement of progenitor cells along wicking fibres and round fibres was assessed. This study demonstrated that wicking fibres enhance the movement of critical growth factors and progenitor cells central for bone regeneration. The results suggested that the incorporation of wicking fibres into large tissue‐engineered constructs may improve the transport of growth factors and progenitor cells essential for bone formation. Copyright © 2014 John Wiley & Sons, Ltd.     

A comprehensive review of recent developments in 3D printing technique for ceramic membrane fabrication for water purification

Additive manufacturing (AM), which is also commonly known as 3D printing, provides flexibility in the manufacturing of complex geometric parts at competitive prices and within a low production time. However, AM has not been used to a large extent in filtration and water treatment processes. AM results in the creation of millions of nanofibers that are sublayered on top of each other and compressed into a thin membrane. AM is a novel technique for fabricating filtration membranes with different shapes, sizes and controlled porosity, which cannot be achieved using conventional process such as electrospinning and knife casting. In this paper, we review the advantages and limitations of AM processes for fabricating ceramic membranes. Moreover, a brief background of AM processes is provided, and their future prospects are examined. Due to their potential benefits for fabrication and flexibility with different materials, AM methods are promising in the field of membrane engineering.

Additive manufacturing (AM), which is also commonly known as 3D printing, provides flexibility in the manufacturing of complex geometric parts at competitive prices and within a low production time.     

Additive manufacturing technology of polymeric materials for customized products: recent developments and future prospective

The worldwide demand for additive manufacturing (AM) is increasing due to its ability to produce more challenging customized objects based on the process parameters for engineering applications. The processing of conventional materials by AM processes is a critically demanded research stream, which has generated a path-breaking scenario in the rapid manufacturing and upcycling of plastics. The exponential growth of AM in the worldwide polymer market is expected to exceed 20 billion US dollars by 2021 in areas of automotive, medical, aerospace, energy and customized consumer products. The development of functional polymers and composites by 3D printing-based technologies has been explored significantly due to its cost-effective, easier integration into customized geometries, higher efficacy, higher precision, freedom of material utilization as compared to traditional injection molding, and thermoforming techniques. Since polymers are the most explored class of materials in AM to overcome the limitations, this review describes the latest research conducted on petroleum-based polymers and their composites using various AM techniques such as fused filament fabrication (FFF), selective laser sintering (SLS), and stereolithography (SLA) related to 3D printing in engineering applications such as biomedical, automotive, aerospace and electronics.

The worldwide demand for additive manufacturing (AM) is increasing due to its ability to produce more challenging customized objects based on the process parameters for engineering applications.     

TGF‐β1 enhances contractility in engineered skeletal muscle

Scaffoldless engineered 3D skeletal muscle tissue created from satellite cells offers the potential to replace muscle tissue that is lost due to severe trauma or disease. Transforming growth factor‐beta 1 (TGF‐β1) plays a vital role in mediating migration and differentiation of satellite cells during the early stages of muscle development. Additionally, TGF‐β1 promotes collagen type I synthesis in the extracellular matrix (ECM) of skeletal muscle, which provides a passive elastic substrate to support myofibres and facilitate the transmission of force. To determine the role of TGF‐β1 in skeletal muscle construct formation and contractile function in vitro, we created tissue‐engineered 3D skeletal muscle constructs with varying levels of recombinant TGF‐β1 added to the cell culture medium. Prior to the addition of TGF‐β1, the primary cell population was composed of 75% Pax7‐positive cells. The peak force for twitch, tetanus and spontaneous force were significantly increased in the presence of 2.0 ng/ml TGF‐β1 when compared to 0, 0.5 and 1.0 ng/ml TGF‐β1. Visualization of the cellular structure with H&E and with immunofluorescence staining for sarcomeric myosin heavy chains and collagen type I showed denser regions of better organized myofibres in the presence of 2.0 ng/ml TGF‐β1 versus 0, 0.5 and 1.0 ng/ml. The addition of 2.0 ng/ml TGF‐β1 to the culture medium of engineered 3D skeletal muscle constructs enhanced contractility and extracellular matrix organization. Copyright © 2012 John Wiley & Sons, Ltd.     

Development of volume‐stable adipose tissue constructs using polycaprolactone‐based polyurethane scaffolds and fibrin hydrogels

Adipose tissue engineering aims at the restoration of soft tissue defects and the correction of contour deformities. It is therefore crucial to provide functional adipose tissue implants with appropriate volume stability. Here, we investigate two different fibrin formulations, alone or in combination with biodegradable polyurethane (PU) scaffolds as additional support structures, with regard to their suitability to generate volume‐stable adipose tissue constructs. Human adipose‐derived stem cells (ASCs) were incorporated in a commercially available fibrin sealant as well as a stable fibrin hydrogel previously developed by our group. The composite constructs made from the commercially available fibrin and porous poly(ε‐caprolactone)‐based polyurethane scaffolds exhibited increased volume stability as compared to fibrin gels alone; however, only constructs using the stable fibrin gels completely maintained their size and weight for 21 days. Adipogenesis of ASCs was not impaired by the additional PU scaffold. After induction with a common hormonal cocktail, for constructs with either fibrin formulation, strong adipogenic differentiation of ASCs was observed after 21 days in vitro. Furthermore, upregulation of adipogenic marker genes was demonstrated at mRNA (PPARγ, C/EBPα, GLUT4 and aP2; qRT–PCR) and protein (leptin; ELISA) levels. Stable fibrin/PU constructs were further evaluated in a pilot in vivo study, resulting in areas of well‐vascularized adipose tissue within the implants after only 5 weeks. Copyright © 2013 John Wiley & Sons, Ltd.