Supercritical emulsion extraction fabricated PLA/PLGA micro/nano carriers for growth factor delivery: Release profiles and cytotoxicity

Ligand-Free Silver Nanoparticles: An Innovative Strategy against Viruses and Bacteria

The spread of antibiotic-resistant bacteria and the rise of emerging and re-emerging viruses in recent years constitute significant public health problems. Therefore, it is necessary to develop new antimicrobial strategies to overcome these challenges. Herein, we describe an innovative method to synthesize ligand-free silver nanoparticles by Pulsed Laser Ablation in Liquid (PLAL-AgNPs). Thus produced, nanoparticles were characterized by total X-ray fluorescence, zeta potential analysis, transmission electron microscopy (TEM), and nanoparticle tracking analysis (NTA). A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was performed to evaluate the nanoparticles' cytotoxicity. Their potential was evaluated against the enveloped herpes simplex virus type 1 (HSV-1) and the naked poliovirus type 1 (PV-1) by plaque reduction assays and confirmed by real-time PCR and fluorescence microscopy, showing that nanoparticles interfered with the early stage of infection. Their action was also examined against different bacteria. We observed that the PLAL-AgNPs exerted a strong effect against both methicillin-resistant Staphylococcus aureus (S. aureus MRSA) and Escherichia coli (E. coli) producing extended-spectrum β-lactamase (ESBL). In detail, the PLAL-AgNPs exhibited a bacteriostatic action against S. aureus and a bactericidal activity against E. coli. Finally, we proved that the PLAL-AgNPs were able to inhibit/degrade the biofilm of S. aureus and E. coli.

The Other Side of Plastics: Bioplastic-Based Nanoparticles for Drug Delivery Systems in the Brain

Plastics have changed human lives, finding a broad range of applications from packaging to medical devices. However, plastics can degrade into microscopic forms known as micro- and nanoplastics, which have raised concerns about their accumulation in the environment but mainly about the potential risk to human health. Recently, biodegradable plastic materials have been introduced on the market. These polymers are biodegradable but also bioresorbable and, indeed, are fundamental tools for drug formulations, thanks to their transient ability to pass through biological barriers and concentrate in specific tissues. However, this "other side" of bioplastics raises concerns about their toxic potential, in the form of micro- and nanoparticles, due to easier and faster tissue accumulation, with unknown long-term biological effects. This review aims to provide an update on bioplastic-based particles by analyzing the advantages and drawbacks of their potential use as components of innovative formulations for brain diseases. However, a critical analysis of the literature indicates the need for further studies to assess the safety of bioplastic micro- and nanoparticles despite they appear as promising tools for several nanomedicine applications.

Green Processing of Neat Poly(lactic acid) Using Carbon Dioxide under Elevated Pressure for Preparation of Advanced Materials: A Review (2012-2022)

This review provides a concise overview of up-to-date developments in the processing of neat poly(lactic acid) (PLA), improvement in its properties, and preparation of advanced materials using a green medium (CO₂ under elevated pressure). Pressurized CO₂ in the dense and supercritical state is a superior alternative medium to organic solvents, as it is easily available, fully recyclable, has easily tunable properties, and can be completely removed from the final material without post-processing steps. This review summarizes the state of the art on PLA drying, impregnation, foaming, and particle generation by the employment of dense and supercritical CO₂ for the development of new materials. An analysis of the effect of processing methods on the final material properties was focused on neat PLA and PLA with an addition of natural bioactive components. It was demonstrated that CO₂-assisted processes enable the control of PLA properties, reduce operating times, and require less energy compared to conventional ones. The described environmentally friendly processing techniques and the versatility of PLA were employed for the preparation of foams, aerogels, scaffolds, microparticles, and nanoparticles, as well as bioactive materials. These PLA-based materials can find application in tissue engineering, drug delivery, active food packaging, compostable packaging, wastewater treatment, or thermal insulation, among others.

Tendon tissue engineering: An overview of biologics to promote tendon healing and repair

Tendons are dense connective tissues with a hierarchical polarized structure that respond to and adapt to the transmission of muscle contraction forces to the skeleton, enabling motion and maintaining posture. Tendon injuries, also known as tendinopathies, are becoming more common as populations age and participation in sports/leisure activities increases. The tendon has a poor ability to self-heal and regenerate given its intrinsic, constrained vascular supply and exposure to frequent, severe loading. There is a lack of understanding of the underlying pathophysiology, and it is not surprising that disorder-targeted medicines have only been partially effective at best. Recent tissue engineering approaches have emerged as a potential tool to drive tendon regeneration and healing. In this review, we investigated the physiochemical factors involved in tendon ontogeny and discussed their potential application in vitro to reproduce functional and self-renewing tendon tissue. We sought to understand whether stem cells are capable of forming tendons, how they can be directed towards the tenogenic lineage, and how their growth is regulated and monitored during the entire differentiation path. Finally, we showed recent developments in tendon tissue engineering, specifically the use of mesenchymal stem cells (MSCs), which can differentiate into tendon cells, as well as the potential role of extracellular vesicles (EVs) in tendon regeneration and their potential for use in accelerating the healing response after injury.

3D in-vitro cultures of human bone marrow and Wharton’s jelly derived mesenchymal stromal cells show high chondrogenic potential

In this study, chondrogenic potentials of 3D high-density cultures of Bone Marrow (BM) and Wharton’s Jelly (WJ)-derived mesenchymal stromal cells (MSCs) was investigated by chondrogenesis- and cytokine-related gene expression over a 16-day culture period supplemented with human transforming growth factor (hTGF)-β1 at 10 ng/ml. In BM-MSC 3D models, a marked upregulation of chondrogenesis-related genes, such as SOX9, COL2A1, and ACAN (all p < 0.05) and formation of spherical pellets with structured type II collagen fibers were observed. Similarly, WJ-based high-density culture appeared higher in size and more regular in shape, with a significant overexpression of COL2A1 and ACAN (all p < 0.05) at day 16. Moreover, a similar upregulation trend was documented for IL-6 and IL-10 expression in both BM and WJ 3D systems. In conclusion, MSC-based high-density cultures can be considered a promising in vitro model of cartilage regeneration and tissue engineering. Moreover, our data support the use of WJ-MSCs as a valid alternative for chondrogenic commitment of stem cells in regenerative medicine.

Biomaterials and Extracellular Vesicle Delivery: Current Status, Applications and Challenges

In this review, we will discuss the current status of extracellular vesicle (EV) delivery via biopolymeric scaffolds for therapeutic applications and the challenges associated with the development of these functionalized scaffolds. EVs are cell-derived membranous structures and are involved in many physiological processes. Naïve and engineered EVs have much therapeutic potential, but proper delivery systems are required to prevent non-specific and off-target effects. Targeted and site-specific delivery using polymeric scaffolds can address these limitations. EV delivery with scaffolds has shown improvements in tissue remodeling, wound healing, bone healing, immunomodulation, and vascular performance. Thus, EV delivery via biopolymeric scaffolds is becoming an increasingly popular approach to tissue engineering. Although there are many types of natural and synthetic biopolymers, the overarching goal for many tissue engineers is to utilize biopolymers to restore defects and function as well as support host regeneration. Functionalizing biopolymers by incorporating EVs works toward this goal. Throughout this review, we will characterize extracellular vesicles, examine various biopolymers as a vehicle for EV delivery for therapeutic purposes, potential mechanisms by which EVs exert their effects, EV delivery for tissue repair and immunomodulation, and the challenges associated with the use of EVs in scaffolds.

Synthesis and Characterization of a Novel Composite Scaffold Based on Hyaluronic Acid and Equine Type I Collagen

Herein, the synthesis and characterization of a novel composite biopolymer scaffold—based on equine type I collagen and hyaluronic acid—were described by using a reaction in heterogeneous phase. The resulting biomimetic structure was characterized in terms of chemical, physical, and cytotoxicity properties using human-derived lymphocytes and chondrocytes. Firstly, FT-IR data proved a successful reticulation of hyaluronic acid within collagen structure with the appearance of a new peak at a wavenumber of 1735 cm⁻¹ associated with ester carbonyl stretch. TGA and DSC characterizations confirmed different thermal stability of cross-linked scaffolds while morphological analysis by scanning electron microscopy (SEM) suggested the presence of a highly porous structure with open and interconnected void areas suitable for hosting cells. The enzymatic degradation profile confirmed scaffold higher endurance with collagenase as compared with collagen alone. However, it was particularly interesting that the mechanical behavior of the composite scaffold showed an excellent shape memory, especially when it was hydrated, with an improved Young’s modulus of 9.96 ± 0.53 kPa (p ≤ 0.001) as well as a maximum load at 97.36 ± 3.58 kPa compared to the simple collagen scaffold that had a modulus of 1.57 ± 0.08 kPa and a maximum load of 36.91 ± 0.24 kPa. Finally, in vitro cytotoxicity confirmed good product safety with human lymphocytes (viability of 81.92 ± 1.9 and 76.37 ± 1.2 after 24 and 48 h, respectively), whereas excellent gene expression profiles of chondrocytes with a significant upregulation of SOX9 and ACAN after 10 days of culture indicated our scaffold’s ability of preserving chondrogenic phenotype. The described material could be considered a potential tool to be implanted in patients with cartilage defects.

Supercritical Antisolvent Technique for the Production of Breathable Naringin Powder

Flavonoids are polyphenolic compounds largely present in fruits and vegetables possessing antioxidant properties, anti-inflammatory and antibacterial activities. Their use in clinical practice is very poor due to their low bioavailability, susceptibility to oxidation and degradation. Moreover, their slight solubility in biological fluids and a consequent low dissolution rate leads to an irregular absorption from solid dosage forms, even though, anti-inflammatory formulations could be used as support for several disease treatment, i.e. the COVID-19 syndrome. To improve flavonoid bioavailability particle size of the powder can be reduced to make it breathable and to promote the absorption in the lung tissues. Supercritical fluid based antisolvent technique has been used to produce naringin particles, with size, shape and density as well as free flowing properties able to fit inhalation needs. The dried particles are produced with the removal of the solvent at lower temperatures compared to the most used traditional micronization processes, such as spray drying. The best breathable fraction for naringin particles is obtained for particles with a d₅₀~7 µm manufactured at 35 °C-150 bar and at 60 °C-130 bar, corresponding to 32.6% and 36.7% respectively. The powder is produced using a high CO₂ molar fraction (0.99) that assure a better removal of the solvent. NuLi-1 cell line of immortalised bronchial epithelial cells adopted to evaluate powder cytotoxicity indicated after 24 h absence of toxicity at concentration of 25 µM.

Injectable, Anti-Cancer Drug-Eluted Chitosan Microspheres against Osteosarcoma

The purpose of this study is to fabricate different anti-cancer drug-eluted chitosan microspheres for combination therapy of osteosarcoma. In this study, electrospray in combination with ground liquid nitrogen was utilized to manufacture the microspheres. The size of obtained chitosan microspheres was uniform, and the average diameter was 532 μm. The model drug release rate and biodegradation rate of chitosan microspheres could be controlled by the glutaraldehyde vapor crosslinking time. Then the 5-fluorouracil (5-FU), paclitaxel (PTX), and Cis-dichlorodiammine-platinum (CDDP) eluted chitosan microspheres were prepared, and two osteosarcoma cell lines, namely, HOS and MG-63, were selected as cell models for in vitro demonstration. We found the 5-FU microspheres, PTX microspheres, and CDDP microspheres could significantly inhibit the growth and migration of both HOS and MG-63 cells. The apoptosis of both cells treated with 5-FU microspheres, PTX microspheres, and CDDP microspheres was significantly increased compared to the counterparts of control and blank groups. The anti-cancer drug-eluted chitosan microspheres show great potential for the treatment of osteosarcoma.

Lipid nano-vesicles for thyroid hormone encapsulation: A comparison between different fabrication technologies, drug loading, and an in vitro delivery to human tendon stem/progenitor cells in 2D and 3D culture

Phosphatidylcholine (PC) vesicles loaded with Triiodothyronine (T3) were fabricated using different manufacturing methods: thin layer hydration plus sonication (TF-UF), supercritical liposome formation (SC), and microfluidic technology (MF). Vesicles obtained by MF had the lowest mean diameter (88.61 ± 44.48 nm) with a Zeta Potential of -20.1 ± 5.90 mV and loading of 10 mg/g (encapsulation efficiency: 57%). In contrast, SC vesicles showed extremely low encapsulation efficiency (<10%) probably due to T3 solubility in ethanol/carbon dioxide mixture; despite TF-UF vesicles exhibiting good size (167.7 ± 90 nm; Zp -8.50 ± 0.60 mV) and loading (10 mg/g), poor mass recovery was obtained (50% loss). MF vesicles had low cytotoxicity, and they were well enough internalized by both HeLa and human tendon stem/progenitor cells (hTSPCs). Their biological activity was also monitored in both 2D and 3D cultures of hTSPCs supplemented with therapeutical concentrations of PC/T3 nano-liposomes. 2D culture showed almost similar constitutive gene expression compared to control culture supplemented with free-T3. On the contrary, when hTPSCs 3D culture was assembled, it showed a more evident homogeneous distribution of FITC labeled vesicles within the high-density structure and a significant upregulation of cell constitutive genes, such as type I Collagen (4.8-fold; p < 0.0001) at day 7, compared to the control, suggesting that T3/PC formulation has increased T3 cytosolic concentration, thus improving cells metabolic activity. The study supported MF technology for nano-carriers fabrication and opens perspectives on the activity of PC/T3 nano-vesicles as innovative formulations for TPSCs stimulation in ECM secretion.

Electrospun Membranes Designed for Burst Release of New Gold-Complexes Inducing Apoptosis of Melanoma Cells

Two non-commercial metallic Au-based complexes were tested against one of the most aggressive malignant melanomas of the skin (MeWo cells), through cell viability and time-lapse live-cell imaging system assays. The tests with the complexes were carried out both in the form of free metallic complexes, directly in contact with the MeWo cell line culture, and embedded in fibers of Polycaprolactone (PCL) membranes produced by the electrospinning technique. Membranes functionalized with complexes were prepared to evaluate the efficiency of the membranes against the melanoma cells and therefore their feasibility in the application as an antitumoral patch for topical use. Both series of tests highlighted a very effective antitumoral activity, manifesting a very relevant cell viability inhibition after both 24 h and 48 h. In the case of the AuM1 complex at the concentration of 20 mM, melanoma cells completely died in this short period of time. A mortality of around 70% was detected from the tests performed using the membranes functionalized with AuM1 complex at a very low concentration (3 wt.%), even after 24 h of the contact period. The synthesized complexes also manifest high selectivity with respect to the MeWo cells. The peculiar structural and morphological organization of the nanofibers constituting the membranes allows for a very effective antitumoral activity in the first 3 h of treatment. Experimental points of the release profiles were perfectly fitted with theoretical curves, which easily allow interpretation of the kinetic phenomena occurring in the release of the synthesized complexes in the chosen medium.

Fabrication and evaluation of customized implantable drug delivery system for orthopedic therapy based on 3D printing technologies

A customized implantable drug delivery system with the dual functions of playing a supporting role and providing continuous bacteriostasis is of great importance during the treatment of bone defect diseases. The main objective of this study was to explore the potential of using three-dimensional (3D) printing technologies to fabricate customized implants. Ciprofloxacin hydrochloride (Cipro) was chosen as the model drug, and two printing technologies, semisolid extrusion (SSE) and fused deposition modeling (FDM) were introduced. Six kinds of implants with customized irregular shapes were printed via FDM technology. Two kinds of implants with customized dosages were constructed via SSE technology. In addition, three kinds of implants with customized internal structures were produced via FDM and SSE technologies. The data for morphology, dimensions and mechanical properties demonstrated satisfactory printability and good printing accuracy when applying SSE and FDM technologies to produce the customized implants. The dissolution curves indicated that the desired customized drug release could be achieved by designing the specific internal structures. The biocompatibility examination showed that the printed implants possessed outstanding biocompatibility. In conclusion, all results suggested that 3D printing technologies provide a feasible method and novel strategy to fabricate customized implantable drug delivery systems.

Additive manufacturing of cartilage-mimetic scaffolds as off-the-shelf implants for joint regeneration

Biomimetic scaffolds that provide a tissue-specific environment to cells are particularly promising for tissue engineering and regenerative medicine applications. The goal of this study was to integrate emerging additive manufacturing and biomaterial design strategies to produce articular cartilage (AC) mimetic scaffolds that could be used as 'off-the-shelf' implants for joint regeneration. To this end alginate sulfate, a sulfated glycosaminoglycan (sGAG) mimic, was used to functionalize porous alginate-based scaffolds and to support the sustained release of transforming growth factor-β3 (TGF-β3). Covalent crosslinking dramatically improved the elasticity of the alginate/alginate sulfate scaffolds, while scaffold architecture could be tailored using a directional freezing technique. Introducing such an anisotropic architecture was found to promote mesenchymal stem cell (MSC) infiltration into the scaffold and to direct the orientation of the deposited extracellular matrix, leading to the development of cartilage tissue with a biomimetic zonal architecture. In vitro experiments also demonstrated the capacity of the sulfated scaffolds to both enhance chondrogenesis of MSCs and to control the release of TGF-β3, leading to the development of a tissue rich in sGAG and type II collagen. The scaffolds were further reinforced with a 3D printed PLCL framework, leading to composite implants that were more elastic than those reinforced with PCL, and which better mimicked the bulk mechanical properties of native cartilage tissue. The ability of this composite scaffold to support chondrogenesis was then confirmed within a dynamic culture system. Altogether, these findings demonstrate the potential of such biomimetic scaffolds as putative 'single-stage' or 'off-the-shelf' strategies for articular cartilage regeneration.

Pharmaceutical Applications of Supercritical Fluid Extraction of Emulsions for Micro-/Nanoparticle Formation

Micro-/nanoparticle formulations containing drugs with or without various biocompatible excipients are widely used in the pharmaceutical field to improve the physicochemical and clinical properties of the final drug product. Among the various micro-/nanoparticle production technologies, emulsion-based particle formation is the most widely used because of its unique advantages such as uniform generation of spherical small particles and higher encapsulation efficiency (EE). For this emulsion-based micro-/nanoparticle technology, one of the most important factors is the extraction efficiency associated with the fast removal of the organic solvent. In consideration of this, a technology called supercritical fluid extraction of emulsions (SFEE) that uses the unique mass transfer mechanism and solvent power of a supercritical fluid (SCF) has been proposed to overcome the shortcomings of several conventional technologies such as solvent evaporation, extraction, and spray drying. This review article presents the main aspects of SFEE technology for the preparation of micro-/nanoparticles by focusing on its pharmaceutical applications, which have been organized and classified according to several types of drug delivery systems and active pharmaceutical ingredients. It was definitely confirmed that SFEE can be applied in a variety of drugs from water-soluble to poorly water-soluble. In addition, it has advantages such as low organic solvent residual, high EE, desirable release control, better particle size control, and agglomeration prevention through efficient and fast solvent removal compared to conventional micro-/nanoparticle technologies. Therefore, this review will be a good resource for determining the applicability of SFEE to obtain better pharmaceutical quality when researchers in related fields want to select a suitable manufacturing process for preparing desired micro-/nanoparticle drug delivery systems containing their active material.

Magnetization-Switchable Implant System to Target Delivery of Stem Cell-Loaded Bioactive Polymeric Microcarriers

Various magnetic microcarrier systems capable of transporting cells to target lesions are developed for therapeutic agent-based tissue regeneration. However, the need for bioactive molecules and cells, the potential toxicity of the microcarrier, and the large volume and limited workspace of the magnetic targeting device remain challenging issues associated with microcarrier systems. Here, a multifunctional magnetic implant system is presented for targeted delivery, secure fixation, and induced differentiation of stem cells. This magnetic implant system consists of a biomaterial-based microcarrier containing bioactive molecules, a portable magnet array device, and a biocompatible paramagnetic implant. Among biomedical applications, the magnetic implant system is developed for knee cartilage repair. The various functions of these components are verified through in vitro, phantom, and ex vivo tests. As a result, a single microcarrier can load ≈1.52 ng of transforming growth factor β (TGF-β1) and 3.3 × 10³ of stem cells and stimulate chondrogenic differentiation without extra bioactive molecule administration. Additionally, the implant system demonstrates high targeting efficiency (over 90%) of the microcarriers in a knee phantom and ex vivo pig knee joint. The results show that this implant system, which overcomes the limitations of the existing magnetic targeting system, represents an important advancement in the field.

3D Biomimetic Scaffold for Growth Factor Controlled Delivery: An In-Vitro Study of Tenogenic Events on Wharton's Jelly Mesenchymal Stem Cells

The present work described a bio-functionalized 3D fibrous construct, as an interactive teno-inductive graft model to study tenogenic potential events of human mesenchymal stem cells collected from Wharton’s Jelly (hWJ-MSCs). The 3D-biomimetic and bioresorbable scaffold was functionalized with nanocarriers for the local controlled delivery of a teno-inductive factor, i.e., the human Growth Differentiation factor 5 (hGDF-5). Significant results in terms of gene expression were obtained. Namely, the up-regulation of Scleraxis (350-fold, p ≤ 0.05), type I Collagen (8-fold), Decorin (2.5-fold), and Tenascin-C (1.3-fold) was detected at day 14; on the other hand, when hGDF-5 was supplemented in the external medium only (in absence of nanocarriers), a limited effect on gene expression was evident. Teno-inductive environment also induced pro-inflammatory, (IL-6 (1.6-fold), TNF (45-fold, p ≤ 0.001), and IL-12A (1.4-fold)), and anti-inflammatory (IL-10 (120-fold) and TGF-β1 (1.8-fold)) cytokine expression upregulation at day 14. The presented 3D construct opens perspectives for the study of drug controlled delivery devices to promote teno-regenerative events.

Chondrogenic Commitment of Human Bone Marrow Mesenchymal Stem Cells in a Perfused Collagen Hydrogel Functionalized with hTGF-β1-Releasing PLGA Microcarrier

Tissue engineering strategies can be relevant for cartilage repair and regeneration. A collagen matrix was functionalized with the addition of poly-lactic-co-glycolic acid microcarriers (PLGA-MCs) carrying a human Transforming Growth Factor β1 (hTFG-β1) payload, to provide a 3D biomimetic environment with the capacity to direct stem cell commitment towards a chondrogenic phenotype. PLGA-MCs (mean size 3 ± 0.9 μm) were prepared via supercritical emulsion extraction technology and tailored to sustain delivery of payload into the collagen hydrogel for 21 days. PLGA-MCs were coseeded with human Bone Marrow Mesenchymal Stem Cells (hBM-MSCs) in the collagen matrix. Chondrogenic induction was suggested when dynamic perfusion was applied as indicated by transcriptional upregulation of COL2A1 gene (5-fold; p < 0.01) and downregulation of COL1A1 (0.07-fold; p < 0.05) and COL3A1 (0.11-fold; p < 0.05) genes, at day 16, as monitored by qRT-PCR. Histological and quantitative-immunofluorescence (qIF) analysis confirmed cell activity by remodeling the synthetic extracellular matrix when cultured in perfused conditions. Static constructs lacked evidence of chondrogenic specific gene overexpression, which was probably due to a reduced mass exchange, as determined by 3D system Finite Element Modelling (FEM) analysis. Proinflammatory (IL-6, TNF, IL-12A, IL-1β) and anti-inflammatory (IL-10, TGF-β1) cytokine gene expression by hBM-MSC was observed only in dynamic culture (TNF and IL-1β 10-fold, p < 0.001; TGF-β1 4-fold, p < 0.01 at Day 16) confirming the cells’ immunomodulatory activity mainly in relation to their commitment and not due to the synthetic environment. This study supports the use of 3D hydrogel scaffolds, equipped for growth factor controlled delivery, as tissue engineered models for the study of in vitro chondrogenic differentiation and opens clinical perspectives for injectable collagen-based advanced therapy systems.

Amnion-Derived Teno-Inductive Secretomes: A Novel Approach to Foster Tendon Differentiation and Regeneration in an Ovine Model

Regenerative medicine has greatly progressed, but tendon regeneration mechanisms and robust in vitro tendon differentiation protocols remain to be elucidated. Recently, tendon explant co-culture (CO) has been proposed as an in vitro model to recapitulate the microenvironment driving tendon development and regeneration. Here, we explored standardized protocols for production and storage of bioactive tendon-derived secretomes with an evaluation of their teno-inductive effects on ovine amniotic epithelial cells (AECs). Teno-inductive soluble factors were released in culture-conditioned media (CM) only in response to active communication between tendon explants and stem cells (CMCO). Unsuccessful tenogenic differentiation in AECs was noted when exposed to CM collected from tendon explants (CMFT) only, whereas CMCO upregulated SCXB, COL I and TNMD transcripts, in AECs, alongside stimulation of the development of mature 3D tendon-like structures enriched in TNMD and COL I extracellular matrix proteins. Furthermore, although the tenogenic effect on AECs was partially inhibited by freezing CMCO, this effect could be recovered by application of an in vivo-like physiological oxygen (2% O2) environment during AECs tenogenesis. Therefore, CMCO can be considered as a waste tissue product with the potential to be used for the development of regenerative bio-inspired devices to innovate tissue engineering application to tendon differentiation and healing.