The fusion of tissue spheroids attached to pre-stretched electrospun polyurethane scaffolds

Bioprinting Using Organ Building Blocks: Spheroids, Organoids, and Assembloids

Three-dimensional (3D) bioprinting, a promising advancement in tissue engineering technology, involves the robotic, layer-by-layer additive biofabrication of functional 3D tissue and organ constructs. This process utilizes biomaterials, typically hydrogels and living cells, following digital models. Traditional tissue engineering uses a classic triad of living cells, scaffolds, and physicochemical signals in bioreactors. A scaffold is a temporary, often biodegradable, support structure. Tissue engineering primarily falls into two categories: (i) scaffold based and (ii) scaffold free. The latter, scaffold-free 3D bioprinting, is gaining increasing popularity. Organ building blocks (OBB), capable of self-assembly and self-organization, such as tissue spheroids, organoids, and assembloids, have begun to be utilized in scaffold-free bioprinting. This article discusses the expanding range of OBB, presents the rapidly evolving collection of bioprinting and bioassembly methods using these OBB, and finally, outlines the advantages, challenges, and future perspectives of using OBB in organ printing.

Recapitulating the Drifting and Fusion of Two-Generation Spheroids on Concave Agarose Microwells

Cells with various structures and proteins naturally come together to cooperate in vivo. This study used cell spheroids cultured in agarose micro-wells as a 3D model to study the movement of cells or spheroids toward other spheroids. The formation dynamics of tumor spheroids and the interactions of two batches of cells in the agarose micro-wells were studied. The results showed that a concave bottom micro-well (diameter: 2 mm, depth: 2 mm) prepared from 3% agarose could be used to study the interaction of two batches of cells. The initial tumor cell numbers from 5 × 103 cells/well to 6 × 104 cells/well all could form 3D spheroids after 3 days of incubation. Adding the second batch of DU 145 cells to the existing DU 145 spheroid resulted in the formation of satellite cell spheroids around the existing parental tumor spheroid. Complete fusion of two generation cell spheroids was observed when the parental spheroids were formed from 1 × 104 and 2 × 104 cells, and the second batch of cells was 5 × 103 per well. A higher amount of the second batch of cells (1 × 104 cell/well) led to the formation of independent satellite spheroids after 48 h of co-culture, suggesting the behavior of the second batch of cells towards existing parental spheroids depended on various factors, such as the volume of the parental spheroids and the number of the second batch cells. The interactions between the tumor spheroids and Human Umbilical Vein Endothelial Cells (HUVECs) were modeled on concave agarose micro-wells. The HUVECs (3 × 103 cell/well) were observed to gather around the parental tumor spheroids formed from 1 × 104, 2 × 104, and 3 × 104 cells per well rather than aggregate on their own to form HUVEC spheroids. This study highlights the importance of analyzing the biological properties of cells before designing experimental procedures for the sequential fusion of cell spheroids. The study further emphasizes the significant roles that cell density and the volume of the spheroids play in determining the location and movement of cells.

Mesenchymal Stromal Cells Adapt to Chronic Tendon Disease Environment with an Initial Reduction in Matrix Remodeling

Tendon lesions are common sporting injuries in humans and horses alike. The healing process of acute tendon lesions frequently results in fibrosis and chronic disease. In horses, local mesenchymal stromal cell (MSC) injection is an accepted therapeutic strategy with positive influence on acute lesions. Concerning the use of MSCs in chronic tendon disease, data are scarce but suggest less therapeutic benefit. However, it has been shown that MSCs can have a positive effect on fibrotic tissue. Therefore, we aimed to elucidate the interplay of MSCs and healthy or chronically diseased tendon matrix. Equine MSCs were cultured either as cell aggregates or on scaffolds from healthy or diseased equine tendons. Higher expression of tendon-related matrix genes and tissue inhibitors of metalloproteinases (TIMPs) was found in aggregate cultures. However, the tenogenic transcription factor scleraxis was upregulated on healthy and diseased tendon scaffolds. Matrix metalloproteinase (MMPs) expression and activity were highest in healthy scaffold cultures but showed a strong transient decrease in diseased scaffold cultures. The release of glycosaminoglycan and collagen was also higher in scaffold cultures, even more so in those with tendon disease. This study points to an early suppression of MSC matrix remodeling activity by diseased tendon matrix, while tenogenic differentiation remained unaffected.

Minispheroids as a Tool for Ligament Tissue Engineering: Do the Self-Assembly Techniques and Spheroid Dimensions Influence the Cruciate Ligamentocyte Phenotype?

Spheroid culture might stabilize the ligamentocyte phenotype. Therefore, the phenotype of lapine cruciate ligamentocyte (L-CLs) minispheroids prepared either by hanging drop (HD) method or by using a novel spheroid plate (SP) and the option of methyl cellulose (MC) for tuning spheroid formation was tested. A total of 250 and 1000 L-CLs per spheroid were seeded as HDs or on an SP before performing cell viability assay, morphometry, gene expression (qRT-PCR) and protein immunolocalization after 7 (HD/SP) and 14 (SP) days. Stable and viable spheroids of both sizes could be produced with both methods, but more rapidly with SP. MC accelerated the formation of round spheroids (HD). Their circular areas decreased significantly during culturing. After 7 days, the diameters of HD-derived spheroids were significantly larger compared to those harvested from the SP, with a tendency of lower circularity suggesting an ellipsoid shape. Gene expression of decorin increased significantly after 7 days (HD, similar trend in SP), tenascin C tended to increase after 7 (HD/SP) and 14 days (SP), whereas collagen type 1 decreased (HD/SP) compared to the monolayer control. The cruciate ligament extracellular matrix components could be localized in all mini-spheroids, confirming their conserved expression profile and their suitability for ligament tissue engineering.

Maintenance of Ligament Homeostasis of Spheroid-Colonized Embroidered and Functionalized Scaffolds after 3D Stretch

Anterior cruciate ligament (ACL) ruptures are usually treated with autograft implantation to prevent knee instability. Tissue engineered ACL reconstruction is becoming promising to circumvent autograft limitations. The aim was to evaluate the influence of cyclic stretch on lapine (L) ACL fibroblasts on embroidered scaffolds with respect to adhesion, DNA and sulphated glycosaminoglycan (sGAG) contents, gene expression of ligament-associated extracellular matrix genes, such as type I collagen, decorin, tenascin C, tenomodulin, gap junctional connexin 43 and the transcription factor Mohawk. Control scaffolds and those functionalized by gas phase fluorination and cross-linked collagen foam were either pre-cultured with a suspension or with spheroids of LACL cells before being subjected to cyclic stretch (4%, 0.11 Hz, 3 days). Stretch increased significantly the scaffold area colonized with cells but impaired sGAGs and decorin gene expression (functionalized scaffolds seeded with cell suspension). Stretching increased tenascin C, connexin 43 and Mohawk but decreased decorin gene expression (control scaffolds seeded with cell suspension). Pre-cultivation of functionalized scaffolds with spheroids might be the more suitable method for maintaining ligamentogenesis in 3D scaffolds compared to using a cell suspension due to a significantly higher sGAG content in response to stretching and type I collagen gene expression in functionalized scaffolds.

A Microfluidic Multisize Spheroid Array for Multiparametric Screening of Anticancer Drugs and Blood-Brain Barrier Transport Properties

Physiological-relevant in vitro tissue models with their promise of better predictability have the potential to improve drug screening outcomes in preclinical studies. Despite the advances of spheroid models in pharmaceutical screening applications, variations in spheroid size and consequential altered cell responses often lead to nonreproducible and unpredictable results. Here, a microfluidic multisize spheroid array is established and characterized using liver, lung, colon, and skin cells as well as a triple-culture model of the blood-brain barrier (BBB) to assess the effects of spheroid size on (a) anticancer drug toxicity and (b) compound penetration across an advanced BBB model. The reproducible on-chip generation of 360 spheroids of five dimensions on a well-plate format using an integrated microlens technology is demonstrated. While spheroid size-related IC50 values vary up to 160% using the anticancer drugs cisplatin (CIS) or doxorubicin (DOX), reduced CIS:DOX drug dose combinations eliminate all lung microtumors independent of their sizes. A further application includes optimizing cell seeding ratios and size-dependent compound uptake studies in a perfused BBB model. Generally, smaller BBB-spheroids reveal an 80% higher compound penetration than larger spheroids while verifying the BBB opening effect of mannitol and a spheroid size-related modulation on paracellular transport properties.

Cell spheroids as a versatile research platform: formation mechanisms, high throughput production, characterization and applications

Three-dimensional cell culture has tremendous advantages to closely mimic the in vivo architecture and microenvironment of healthy tissue and organs, as well as of solid tumors. Spheroids are currently the most attractive 3D model to produce uniform reproducible cell structures as well as a potential basis for engineering large tissues and complex organs. In this review we discuss, from an engineering perspective, processes to obtain uniform 3D cell spheroids, comparing dynamic and static cultures and considering aspects such as mass transfer and shear stress. In addition, computational and mathematical modelling of complex cell spheroid systems are discussed. The non-cell-adhesive hydrogel-based method and dynamic cell culture in bioreactors are focused in detail and the myriad of developed spheroid characterization techniques is presented. The main bottlenecks and weaknesses are discussed, especially regarding the analysis of morphological parameters, cell quantification and viability, gene expression profiles, metabolic behavior and high-content analysis. Finally, a vast set of applications of spheroids as tools for in vitro study model systems is examined, including drug screening, tissue formation, pathologies development, tissue engineering and biofabrication, 3D bioprinting and microfluidics, together with their use in high-throughput platforms.

Stem cell therapy and tissue engineering strategies using cell aggregates and decellularized scaffolds for the rescue of liver failure

Liver failure is a lethal condition with hepatocellular dysfunction, and liver transplantation is presently the only effective treatment. However, due to the limited availability of donors and the potential immune rejection, novel therapeutic strategies are actively sought to restore the normal hepatic architectures and functions, especially for livers with inherited metabolic dysfunctions or chronic diseases. Although the conventional cell therapy has shown promising results, the direct infusion of hepatocytes is hampered by limited hepatocyte sources, poor cell viability, and engraftment. Hence, this review mainly highlights the role of stem cells and progenitors as the alternative cell source and summarizes the potential approaches based on tissue engineering to improve the delivery efficiency of cells. Particularly, the underlying mechanisms for cell therapy using stem cells and progenitors are discussed in two main aspects: paracrine effect and cell differentiation. Moreover, tissue-engineering approaches using cell aggregates and decellularized liver scaffolds for bioengineering of functional hepatic constructs are discussed and compared in terms of the potential to replicate liver physiological structures. In the end, a potentially effective strategy combining the premium advantages of stem cell aggregates and decellularized liver scaffolds is proposed as the future direction of liver tissue engineering and regeneration.

Cytoskeleton systems contribute differently to the functional intrinsic properties of chondrospheres

Cytoskeleton systems, actin microfilaments, microtubules (MTs) and intermediate filaments (IFs) provide the biomechanical stability and spatial organization in cells. To understand the specific contributions of each cytoskeleton systems to intrinsic properties of spheroids, we've scrutinized the effects of the cytoskeleton perturbants, cytochalasin D (Cyto D), nocodazole (Noc) and withaferin A (WFA) on fusion, spreading on adhesive surface, morphology and biomechanics of chondrospheres (CSs). We confirmed that treatment with Cyto D but not with Noc or WFA severely affected CSs fusion and spreading dynamics and significantly reduced biomechanical properties of cell aggregates. Noc treatment affected spheroids spreading but not the fusion and surprisingly enhanced their stiffness. Vimentin intermediate filaments (VIFs) reorganization affected CSs spreading only. The analysis of all three cytoskeleton systems contribution to spheroids intrinsic properties was performed for the first time.

Advanced biomedical applications based on emerging 3D cell culturing platforms

It is of great value to develop reliable in vitro models for cell biology and toxicology. However, ethical issues and the decreasing number of donors restrict the further use of traditional animal models in various fields, including the emerging fields of tissue engineering and regenerative medicine. The huge gap created by the restrictions in animal models has pushed the development of the increasingly recognized three-dimensional (3D) cell culture, which enables cells to closely simulate authentic cellular behaviour such as close cell-to-cell interactions and can achieve higher functionality. Furthermore, 3D cell culturing is superior to the traditional 2D cell culture, which has obvious limitations and cannot closely mimic the structure and architecture of tissues. In this study, we review several methods used to form 3D multicellular spheroids. The extracellular microenvironment of 3D spheroids plays a role in many aspects of biological sciences, including cell signalling, cell growth, cancer cell generation, and anti-cancer drugs. More recently, they have been explored as basic construction units for tissue and organ engineering. We review this field with a focus on the previous research in different areas using spheroid models, emphasizing aqueous two-phase system (ATPS)-based techniques. Multi-cellular spheroids have great potential in the study of biological systems and can closely mimic the in vivo environment. New technologies to form and analyse spheroids such as the aqueous two-phase system and magnetic levitation are rapidly overcoming the technical limitations of spheroids and expanding their applications in tissue engineering and regenerative medicine.

Cartilage and bone tissue engineering using adipose stromal/stem cells spheroids as building blocks

Scaffold-free techniques in the developmental tissue engineering area are designed to mimic in vivo embryonic processes with the aim of biofabricating, in vitro, tissues with more authentic properties. Cell clusters called spheroids are the basis for scaffold-free tissue engineering. In this review, we explore the use of spheroids from adult mesenchymal stem/stromal cells as a model in the developmental engineering area in order to mimic the developmental stages of cartilage and bone tissues. Spheroids from adult mesenchymal stromal/stem cells lineages recapitulate crucial events in bone and cartilage formation during embryogenesis, and are capable of spontaneously fusing to other spheroids, making them ideal building blocks for bone and cartilage tissue engineering. Here, we discuss data from ours and other labs on the use of adipose stromal/stem cell spheroids in chondrogenesis and osteogenesis in vitro. Overall, recent studies support the notion that spheroids are ideal "building blocks" for tissue engineering by “bottom-up” approaches, which are based on tissue assembly by advanced techniques such as three-dimensional bioprinting. Further studies on the cellular and molecular mechanisms that orchestrate spheroid fusion are now crucial to support continued development of bottom-up tissue engineering approaches such as three-dimensional bioprinting.

Gradient-sized control of tumor spheroids on a single chip

Multicellular tumor spheroids are attracting more attention as a physiologically relevant in vitro tumor model for biomedical research. The size of spheroids is one of the critical parameters related to drug penetration and cellular responses. It remains challenging to generate a large number of gradient-sized spheroids in one culture vessel. Here, a liquid-dome method was used to simultaneously produce more than 200 gradient-sized spheroids on an agarose chip. Surface tension effect was used to modulate the liquid spatial distribution and achieve a range of spheroid sizes. MCF-7 cells formed multiple spheroids on the chips for concept validation. It showed that different configurations of the liquid domes exhibited different levels of size control. Relative to the smallest spheroids in the configuration, hemispheric and square domes produced spheroids up to 3.4 and 12.8-fold larger in area, respectively. In addition, the co-culture of MCF-7 and fibroblasts helped to elucidate the tendency of fibroblasts towards the spheroid center. Other size-dependent behaviors were profiled; larger spheroids behaved differently from smaller spheroids in terms of spheroid growth, drug penetration and cellular responses. This method breaks the boundary between the preparation of gradient-sized spheroids and significant time/labour demand. It can be useful for drug screening and in vitro tumor modelling.

4D Biofabrication: Materials, Methods, and Applications

The mission of regenerative medicine is the development of methods to regrow, repair, or replace damaged or diseased cells, organs, or tissues. 3D bioprinting techniques are one of the most promising approaches for engineering the design of artificial tissues. Current 3D bioprinting technologies possess, however, several intrinsic limitations. 4D biofabrication, a recently developed technology with the embedded ability of shape transformation upon response to intrinsic and/or external stimuli, may solve challenges of 3D bioprinting as well as more accurately mimic the dynamics of the native tissues. This article covers recent advances in 4D biofabrication. It gives a detailed picture of used materials and technologies, provides critical comparisons of methods, discusses possibilities and limitations of different 4D biofabrication technologies, and gives examples of applications.

Scaffold-free, label-free and nozzle-free biofabrication technology using magnetic levitational assembly

Tissue spheroids have been proposed as building blocks in 3D biofabrication. Conventional magnetic force-driven 2D patterning of tissue spheroids requires prior cell labeling by magnetic nanoparticles, meanwhile a label-free approach for 3D magnetic levitational assembly has been introduced. Here we present first time report on rapid assembly of 3D tissue construct using scaffold-free, nozzle-free and label-free magnetic levitation of tissue spheroids. Chondrospheres of standard size, shape and capable to fusion have been biofabricated from primary sheep chondrocytes using non-adhesive technology. Label-free magnetic levitation was performed using a prototype device equipped with permanent magnets in presence of gadolinium (Gd³⁺) in culture media, which enables magnetic levitation. Mathematical modeling and computer simulations were used for prediction of magnetic field and kinetics of tissue spheroids assembly into 3D tissue constructs. First, we used polystyrene beads to simulate the assembly of tissue spheroids and to determine the optimal settings for magnetic levitation in presence of Gd³⁺. Second, we proved the ability of chondrospheres to assemble rapidly into 3D tissue construct in the permanent magnetic field in the presence of Gd³⁺. Thus, scaffold- and label-free magnetic levitation of tissue spheroids is a promising approach for rapid 3D biofabrication and attractive alternative to label-based magnetic force-driven tissue engineering.

Directed fusion of cardiac spheroids into larger heterocellular microtissues enables investigation of cardiac action potential propagation via cardiac fibroblasts

Multicellular spheroids generated through cellular self-assembly provide cytoarchitectural complexities of native tissue including three-dimensionality, extensive cell-cell contacts, and appropriate cell-extracellular matrix interactions. They are increasingly suggested as building blocks for larger engineered tissues to achieve shapes, organization, heterogeneity, and other biomimetic complexities. Application of these tissue culture platforms is of particular importance in cardiac research as the myocardium is comprised of distinct but intermingled cell types. Here, we generated scaffold-free 3D cardiac microtissue spheroids comprised of cardiac myocytes (CMs) and/or cardiac fibroblasts (CFs) and used them as building blocks to form larger microtissues with different spatial distributions of CMs and CFs. Characterization of fusing homotypic and heterotypic spheroid pairs revealed an important influence of CFs on fusion kinetics, but most strikingly showed rapid fusion kinetics between heterotypic pairs consisting of one CF and one CM spheroid, indicating that CMs and CFs self-sort in vitro into the intermixed morphology found in the healthy myocardium. We then examined electrophysiological integration of fused homotypic and heterotypic microtissues by mapping action potential propagation. Heterocellular elongated microtissues which recapitulate the disproportionate CF spatial distribution seen in the infarcted myocardium showed that action potentials propagate through CF volumes albeit with significant delay. Complementary computational modeling revealed an important role of CF sodium currents and the spatial distribution of the CM-CF boundary in action potential conduction through CF volumes. Taken together, this study provides useful insights for the development of complex, heterocellular engineered 3D tissue constructs and their engraftment via tissue fusion and has implications for arrhythmogenesis in cardiac disease and repair.

The Self-Assembling Process and Applications in Tissue Engineering

Tissue engineering strives to create neotissues capable of restoring function. Scaffold-free technologies have emerged that can recapitulate native tissue function without the use of an exogenous scaffold. This review will survey, in particular, the self-assembling and self-organization processes as scaffold-free techniques. Characteristics and benefits of each process are described, and key examples of tissues created using these scaffold-free processes are examined to provide guidance for future tissue-engineering developments. We aim to explore the potential of self-assembly and self-organization scaffold-free approaches, detailing the recent progress in the in vitro tissue engineering of biomimetic tissues with these methods toward generating functional tissue replacements.

Electrospun Fibers for Recruitment and Differentiation of Stem Cells in Regenerative Medicine

Electrospinning is a popular technique used to mimic the natural sub-micron features of the native tissue. The ultra-fine fibers provide a favorable extracellular matrix-like environment for regulation of cellular functions. This article summarizes and reviews the current advances in electrospun fiber application and focuses on the novel strategies applied for tissue regeneration and repair. It explores the different factors affecting the attachment and proliferation of mesenchymal stem cells (MSCs) on the electrospun substrates. The influence of different features of electrospun fibers in the differentiation of MSCs into specific lineages (bone, cartilage, tendon/ligament, and nerves) has been elaborated. In addition, the different techniques to mimic the hierarchical features of tissues and its effect on cellular functions are reviewed. Additionally, the new developments like three-dimensional (3D) electrospinning, 3D spheroid double strategy and the comparative analysis of dynamic and static culture on electrospun scaffolds are discussed. With the intricate understanding of the interaction between the cells and the electrospun fiber matrix we can aim to combine the newer strategies to overcome the existing challenges and improve the potential application of electrospun fibers in the field of tissue regeneration and repair.

Quantifying the kinetics and morphological changes of the fusion of spheroid building blocks

Tissue fusion, whereby two or more spheroids coalesce, is a process that is fundamental to biofabrication. We have designed a quantitative, high-throughput platform to investigate the fusion of multicellular spheroids using agarose micro-molds. Spheroids of primary human chondrocytes (HCH) or human breast cancer cells (MCF-7) were self-assembled for 24 h and then brought together to form an array comprised of two spheroids (one doublet) per well. To quantify spheroid fusogenicity, we developed two assays: (1) an initial tack assay, defined as the minimum amount of time for two spheroids to form a mechanically stable tissue complex or doublet, and (2) a fusion assay, in which we defined and tracked key morphological parameters of the doublets as a function of time using wide-field fluorescence microscopy over a 24 h time-lapse. The initial tack of spheroid fusion was measured by inverting the micro-molds and centrifuging doublets at various time points to assess their connectedness. We found that the initial tack between two spheroids forms rapidly, with the majority of doublets remaining intact after centrifugation following just 30 min of fusion. Over the course of 24 h of fusion, several morphological changes occurred, which were quantified using a custom image analysis pipeline. End-to-end doublet lengths decreased over time, doublet widths decreased for chondrocytes and increased for MCF-7, contact lengths increased over time, and chondrocyte doublets exhibited higher intersphere angles at the end of fusion. We also assessed fusion by measuring the fluorescence intensity at the plane of fusion, which increased over time for both cell types. Interestingly, we observed that doublets moved and rotated in the micro-wells during fusion and this rotation was inhibited by ROCK inhibitor Y-27632 and myosin II inhibitor blebbistatin. Understanding and optimizing tissue fusion is essential for creating larger tissues, organs, or other structures using individual microtissues as building parts.

A lab-on-a-chip device for investigating the fusion process of olfactory ensheathing cell spheroids

Understanding the process of fusion of olfactory ensheathing cell spheroids will lead to improvement of cell transplantation therapies to repair spinal cord injuries. The successful fusion of transplanted spheroids will enable alternative transplantation strategies to be developed for in vivo applications. This paper describes the use of a microfluidic device to trap and fuse olfactory ensheathing cell spheroids. The velocity, the pressure distribution in the device were simulated numerically to predict the trapping location. The simulation predicted the optimum flow rates for trapping the spheroids in the later experiments. Simulated particle trajectories were verified experimentally with tracing of fluorescent micro particles. The fusion process of the spheroids was investigated over a period of 48 hours. The microfluidic platform presented here can be used for testing potential drugs that can promote the fusion process and improve the transplantation therapy.

Biotunable acoustic node assembly of organoids

Bioengineering of 3D microtissues from cell spheroids is demonstrated by employing the vibration of acoustic standing waves and its hydrodynamic effect at the bottom of a liquid-carrier chamber. A large number of cell spheroids (>10(4) ) are assembled in seconds into a closely packed structure in a scaffold-free fashion under nodal pattern of the standing waves in a fluidic environment.

Mesoporous silica-layered biopolymer hybrid nanofibrous scaffold: a novel nanobiomatrix platform for therapeutics delivery and bone regeneration

Nanoscale scaffolds that characterize high bioactivity and the ability to deliver biomolecules provide a 3D microenvironment that controls and stimulates desired cellular responses and subsequent tissue reaction. Herein novel nanofibrous hybrid scaffolds of polycaprolactone shelled with mesoporous silica (PCL@MS) were developed. In this hybrid system, the silica shell provides an active biointerface, while the 3D nanoscale fibrous structure provides cell-stimulating matrix cues suitable for bone regeneration. The electrospun PCL nanofibers were coated with MS at controlled thicknesses via a sol-gel approach. The MS shell improved surface wettability and ionic reactions, involving substantial formation of bone-like mineral apatite in body-simulated medium. The MS-layered hybrid nanofibers showed a significant improvement in mechanical properties, in terms of both tensile strength and elastic modulus, as well as in nanomechanical surface behavior, which is favorable for hard tissue repair. Attachment, growth, and proliferation of rat mesenchymal stem cells were significantly improved on the hybrid scaffolds, and their osteogenic differentiation and subsequent mineralization were highly up-regulated by the hybrid scaffolds. Furthermore, the mesoporous surface of the hybrid scaffolds enabled the loading of a series of bioactive molecules, including small drugs and proteins at high levels. The release of these molecules was sustainable over a long-term period, indicating the capability of the hybrid scaffolds to deliver therapeutic molecules. Taken together, the multifunctional hybrid nanofibrous scaffolds are considered to be promising therapeutic platforms for stimulating stem cells and for the repair and regeneration of bone.

Nanocomposite scaffolds incorporated with hydrophobically-functionalized mesoporous nanocarriers for the effective loading and long-term delivery of osteogenic drugs

Large-pore mesoporous nanocarriers were hydrophobically-engineered to load osteogenic drug Dex, which was then generated into nanocomposite fiber scaffolds, demonstrating long-term drug delivery and osteogenic stimulation of stem cells.