A systematic study for optimal cell seeding and culture conditions in a perfusion mode bone-tissue bioreactor

Improvement in Active Cell Proliferation Area at Higher Permeability With Novel TPMS Lattice Structure

The utilization of lattice-based scaffolds emerging as an advance technique over conventional bio-implants in Bone Tissue Engineering. In this study, totally six lattice structures are considered for permeability and wall shear stress (WSS) investigation. Namely triply periodic minimal surfaces (TPMS)-based Gyroid, Schwarz-P, Schwarz-D, and two beam-based structure-Cubic and Fluorite are compared with the proposed new lattice structure at porosity level of 80%, 75%, and 70%. The proposed new lattice has combine characteristic of Gyroid and Schwarz-D TPMS lattice. The permeability is determined through Darcy's law, where the pressure drop across the lattice structure is calculated using a computational fluid dynamics (CFD) tool at flowrate between 0.2 and 10 ml/min. The Cubic and Schwarz-P lattice structures exhibited the highest permeability but at the cost of a lower active surface area for WSS, measuring below 155 mm2, means least cell proliferation occurs while the permeability value in New Lattice structure is in the ideal range with the enhanced active surface area for WSS (514 mm2). The complex internal curvatures of New Lattice promote the cell proliferation while the through-pore holes allow the efficient cell seeding.

Physico-chemical and biological characterization of synthetic and eggshell derived nanohydroxyapatite/carboxymethyl chitosan composites for pulp-dentin tissue engineering

Hybrid nanohydroxyapatite/carboxymethyl chitosan (nHAp-CMC) scaffolds have garnered significant attention in the field of regenerative engineering. The current study comparatively analyzed the physicochemical and biological properties of synthetic nanohydroxyapatite (SnHA)- and eggshell-sourced nanohydroxyapatite (EnHA)- based CMC biocomposites for pulp-dentin regeneration. EnHA and CMC were synthesized through a chemical process, whereas SnHA was commercially obtained. Composite scaffolds of SnHA-CMC and EnHA-CMC (1:5 w/w) were prepared using freeze-drying method. All biomaterials were characterized by FTIR, micro-Raman, XRD, HRSEM-EDX, and TEM analyses, and their in vitro bioactivity was assessed by immersing them in simulated body fluid for 21 days. The biological properties of the composite scaffolds were evaluated by assessing cytocompatibility using MTT assay and biomineralization potential by analyzing the odontogenic gene expressions (ALP, DSPP, DMP-1 and VEGF) in human dental pulp stem cells (DPSCs) using RT-qPCR method. Characterization studies revealed that EnHA displayed higher crystallinity and superior surface morphology compared to SnHA. The composite scaffolds showed a highly interconnected porous microstructure with pore sizes ranging between 60 and 220 μm, ideal for cell seeding. All tested materials, SnHA, EnHA, and their respective composites, displayed high cytocompatibility, increased ALP activity and degree of mineralization with significant upregulation of odontogenic-related genes on DPSCs (p < 0.05). Nevertheless, the odontogenic differentiation potential of EnHA-CMC on DPSCs was significantly higher when compared to SnHA-CMC. The findings from this study highlight the potential of EnHA-CMC as a promising candidate for pulp-dentin engineering.

EnduroBone: A 3D printed bioreactor for extended bone tissue culture

Studies of the effects of external stimuli on bone tissue, disease transmission mechanisms, and potential medication discoveries benefit from long-term tissue viability ex vivo. By simulating the in-vivo environment, bioreactors are essential for studying bone cellular activity throughout biological processes. We present the development of an automated 3D-printed bioreactor EnduroBone designed to sustain the ex-vivo viability of 10 mm diameter cancellous bone cores for an extended period. The device is supplied with two critical parameters for maintaining bone tissue viability: closed-loop continuous flow perfusion of 1 mL/min for nutrient diffusion and waste removal and direct mechanical stimulation with cyclic compression at 13.2 RPM (revolutions per minute) to promote cell viability which can lead to improved tissue stability during ex vivo culturing. The bioreactor addresses several limitations of existing systems and provides a versatile open-source platform for bone cancer research, orthopedic device testing, and other related applications. To validate the bioreactor, fresh swine samples were cultured ex-vivo, and their cell viability was determined to be maintained for up to 28 days. Periodic cell viability assessment through live/dead cell staining and confocal imaging at the start (0 days) and at several time points throughout the culture period (7, 14, 21, and 28 days) was used to demonstrate EnduroBone effectiveness in sustaining bone cell health for the extended period tested.

JANUS: an open-source 3D printable perfusion bioreactor and numerical model-based design strategy for tissue engineering

Bioreactors have been employed in tissue engineering to sustain longer and larger cell cultures, managing nutrient transfer and waste removal. Multiple designs have been developed, integrating sensor and stimulation technologies to improve cellular responses, such as proliferation and differentiation. The variability in bioreactor design, stimulation protocols, and cell culture conditions hampered comparison and replicability, possibly hiding biological evidence. This work proposes an open-source 3D printable design for a perfusion bioreactor and a numerical model-driven protocol development strategy for improved cell culture control. This bioreactor can simultaneously deliver capacitive-coupled electric field and fluid-induced shear stress stimulation, both stimulation systems were validated experimentally and in agreement with numerical predictions. A preliminary in vitro validation confirmed the suitability of the developed bioreactor to sustain viable cell cultures. The outputs from this strategy, physical and virtual, are openly available and can be used to improve comparison, replicability, and control in tissue engineering applications.

Virtual Design of 3D-Printed Bone Tissue Engineered Scaffold Shape Using Mechanobiological Modeling: Relationship of Scaffold Pore Architecture to Bone Tissue Formation

Large bone defects are clinically challenging, with up to 15% of these requiring surgical intervention due to non-union. Bone grafts (autographs or allografts) can be used but they have many limitations, meaning that polymer-based bone tissue engineered scaffolds (tissue engineering) are a more promising solution. Clinical translation of scaffolds is still limited but this could be improved by exploring the whole design space using virtual tools such as mechanobiological modeling. In tissue engineering, a significant research effort has been expended on materials and manufacturing but relatively little has been focused on shape. Most scaffolds use regular pore architecture throughout, leaving custom or irregular pore architecture designs unexplored. The aim of this paper is to introduce a virtual design environment for scaffold development and to illustrate its potential by exploring the relationship of pore architecture to bone tissue formation. A virtual design framework has been created utilizing a mechanical stress finite element (FE) model coupled with a cell behavior agent-based model to investigate the mechanobiological relationships of scaffold shape and bone tissue formation. A case study showed that modifying pore architecture from regular to irregular enabled between 17 and 33% more bone formation within the 4-16-week time periods analyzed. This work shows that shape, specifically pore architecture, is as important as other design parameters such as material and manufacturing for improving the function of bone tissue scaffold implants. It is recommended that future research be conducted to both optimize irregular pore architectures and to explore the potential extension of the concept of shape modification beyond mechanical stress to look at other factors present in the body.

Cell Seeding on 3D Scaffolds for Tissue Engineering and Disease Modeling Applications

Scaffold cell seeding is a crucial step for the standardization and homogeneous maturation of tissue engineered constructs. This is particularly critical in the context of additively manufactured scaffolds whereby large pore size and high porosity usually impedes the retention of the seeding solution resulting in poor seeding efficacy and heterogeneous cell distribution. To circumvent this limitation, a simple yet efficient cell seeding technique is described in this chapter consisting of preincubating the scaffold in 100% serum for 1 h leading to reproducible seeding. A proof of concept is demonstrated using highly porous melt electrowritten polycaprolactone scaffolds as the cell carrier. As cell density, cell distribution, and differentiation within the scaffold are important parameters, various assays are proposed to validate the seeding and perform quality control of the cellularized construct using techniques such as alizarin red, Sirius red, and immunostaining.

An automated 3D-printed perfusion bioreactor combinable with pulsed electromagnetic field stimulators for bone tissue investigations

In bone tissue engineering research, bioreactors designed for replicating the main features of the complex native environment represent powerful investigation tools. Moreover, when equipped with automation, their use allows reducing user intervention and dependence, increasing reproducibility and the overall quality of the culture process. In this study, an automated uni-/bi-directional perfusion bioreactor combinable with pulsed electromagnetic field (PEMF) stimulation for culturing 3D bone tissue models is proposed. A user-friendly control unit automates the perfusion, minimizing the user dependency. Computational fluid dynamics simulations supported the culture chamber design and allowed the estimation of the shear stress values within the construct. Electromagnetic field simulations demonstrated that, in case of combination with a PEMF stimulator, the construct can be exposed to uniform magnetic fields. Preliminary biological tests on 3D bone tissue models showed that perfusion promotes the release of the early differentiation marker alkaline phosphatase. The histological analysis confirmed that perfusion favors cells to deposit more extracellular matrix (ECM) with respect to the static culture and revealed that bi-directional perfusion better promotes ECM deposition across the construct with respect to uni-directional perfusion. Lastly, the Real-time PCR results of 3D bone tissue models cultured under bi-directional perfusion without and with PEMF stimulation revealed that the only perfusion induced a ~ 40-fold up-regulation of the expression of the osteogenic gene collagen type I with respect to the static control, while a ~ 80-fold up-regulation was measured when perfusion was combined with PEMF stimulation, indicating a positive synergic pro-osteogenic effect of combined physical stimulations.

Perfused Platforms to Mimic Bone Microenvironment at the Macro/Milli/Microscale: Pros and Cons

As life expectancy increases, the population experiences progressive ageing. Ageing, in turn, is connected to an increase in bone-related diseases (i.e., osteoporosis and increased risk of fractures). Hence, the search for new approaches to study the occurrence of bone-related diseases and to develop new drugs for their prevention and treatment becomes more pressing. However, to date, a reliable in vitro model that can fully recapitulate the characteristics of bone tissue, either in physiological or altered conditions, is not available. Indeed, current methods for modelling normal and pathological bone are poor predictors of treatment outcomes in humans, as they fail to mimic the in vivo cellular microenvironment and tissue complexity. Bone, in fact, is a dynamic network including differently specialized cells and the extracellular matrix, constantly subjected to external and internal stimuli. To this regard, perfused vascularized models are a novel field of investigation that can offer a new technological approach to overcome the limitations of traditional cell culture methods. It allows the combination of perfusion, mechanical and biochemical stimuli, biological cues, biomaterials (mimicking the extracellular matrix of bone), and multiple cell types. This review will discuss macro, milli, and microscale perfused devices designed to model bone structure and microenvironment, focusing on the role of perfusion and encompassing different degrees of complexity. These devices are a very first, though promising, step for the development of 3D in vitro platforms for preclinical screening of novel anabolic or anti-catabolic therapeutic approaches to improve bone health.

Alginate bone scaffolds coated with a bioactive lactose modified chitosan for human dental pulp stem cells proliferation and differentiation

Bioactive and biodegradable porous scaffolds can hasten the healing of bone defects; moreover, patient stem cells seeded onto scaffolds can enhance the osteoinductive and osteoconductive properties of these biomaterials. In this work, porous alginate/hydroxyapatite scaffolds were functionalized with a bioactive coating of a lactose-modified chitosan (CTL). The highly interconnected porous structure of the scaffold was homogeneously coated with CTL. The scaffolds showed remarkable stability up to 60 days of aging. Human Dental Pulp Stem Cells (hDPSCs) cultured in the presence of CTL diluted in culture medium, showed a slight and negligible increase in terms of proliferation rate; on the contrary, an effect on osteogenic differentiation of the cells was observed as a significant increase in alkaline phosphatase activity. hDPSCs showed higher cell adhesion on CTL-coated scaffolds than on uncoated ones. CTL coating did not affect cell proliferation, but stimulated cell differentiation as shown by alkaline phosphatase activity analysis.

Numerical modelling of osteocyte growth on different bone tissue scaffolds

The most common solution for the regeneration or replacement of damaged bones is the implantation of prostheses comprising ceramic or metallic materials. However, these implants are known to cause problems such as post-operative infections, collapse of the prosthesis, and lack of osseointegration. Consequently, bone tissue engineering was established because of the limitations of such implants. Osteogenic implants offer promising solutions for bone regeneration; however, three-dimensional scaffolds should be used as supportive structures. It is challenging to correctly design these structures and their compositions or properties to provide a microenvironment that promotes tissue regeneration and expedites bone formation. Computational fluid dynamics can be used to model the main phenomena that occur in bioreactors, such as cell metabolism, nutrient transport, and cell culture growth, or to model the influence of several key mechanisms related to the fluid medium, in particular, the wall shear stress. In this work, a new numerical bone cell growth model was developed, which considered the oxygen and nutrient consumption as well as the wall shear stress effect on cell proliferation. The model was implemented using 35 three-dimensional scaffolds of different porosities, and the effect of the main geometrical parameters involved in each scaffold type was analysed. The porosity plays an important role, however, a similar porosity did not guarantee similar shear stress or cell growth among the scaffolds. Randomised trabecular scaffolds, that more closely resembled trabecular bone, showed the highest cell growth values, so these are the best candidates for cell growth in a bioreactor.

Effect of Dual Pore Size Architecture on In Vitro Osteogenic Differentiation in Additively Manufactured Hierarchical Scaffolds

The combination of macro- and microporosity is a potent manner of enhancing osteogenic potential, but the biological events leading to this increase in osteogenesis are not well understood. In this study, we investigated the effect of a dual pore size scaffold on the physical and biological properties, with the hypothesis that cell condensation is the determining factor for enhanced osteogenic differentiation. To this end, a hierarchical scaffold possessing a dual (large and small) pore size was fabricated by combining two additive manufacturing techniques: melt electrospinning writing (MEW) and fused deposition modeling (FDM). The scaffolds showed a mechanical stiffness of 23.2 ± 1.5 MPa similar to the FDM control scaffold, while the hybrid revealed an increased specific surface area of 1.4 ± 0.1 m²/g. The scaffold was cultured with primary human osteoblasts for 28 days, which showed enhanced cell adhesion and proliferation. The hierarchical structure was also beneficial for in vitro alkaline phosphate activity and mineralization and showed an increased expression of osteogenic protein and genes. Mesenchymal condensation markers related to osteoblastic differentiation (CDH2, RhoA, Rac1, and Cdc42) were upregulated in the hybrid construct, demonstrating that the MEW membrane provided an environment more suitable for the recapitulation of cell condensation, which in turn leads to higher osteogenic differentiation. In summary, this study demonstrated that the hierarchical scaffold developed in this paper leads to a significant improvement in the scaffold properties such as increased specific surface area, initial cell adhesion, cell proliferation, and in vitro osteogenesis.

Magnetic-driven dynamic culture promotes osteogenesis of mesenchymal stem cell

Effective nutrient transport and appropriate mechanical stimulation play important roles in production of tissue-engineered bone grafts. In this study, an experimental set-up for magnetic-driven dynamic culture of cells was designed to mimic the microenvironment of the bone tissue. Here, its ability to contribute to osteogenic differentiation was investigated by inoculating human umbilical cord mesenchymal stem cells (HUMSCs) on magnetic scaffolds. The cytocompatibility of the developed magnetic scaffolds was verified for HUMSCs. Magnetic scaffolds seeded with HUMSCs were exposed to magnetic fields. The results showed that magnetic fields did not affect cell activity and promoted HUMSCs osteogenic differentiation. The magnetic scaffolds were magnetically driven for dynamic culture in the experimental set-up to evaluate the influence of HUMSCs osteoblast differentiation. The results indicated that magnetic-driven dynamic culture increased cell alkaline phosphatase (ALP) activity (p < 0.05) and calcium release (p < 0.05) compared with static culture. The effect was demonstrated in the expression of bone-associated genes. Overall, this study showed that magnetic-driven dynamic culture is a promising tool for regenerative bone engineering.

Improving cell seeding efficiency through modification of fiber geometry in 3D printed scaffolds

Cell seeding on 3D scaffolds is a very delicate step in tissue engineering applications, influencing the outcome of the subsequent culture phase, and determining the results of the entire experiment. Thus, it is crucial to maximize its efficiency. To this purpose, a detailed study of the influence of the geometry of the scaffold fibers on dynamic seeding efficiency is presented. 3D printing technology was used to realize PLA porous scaffolds, formed by fibers with a non-circular cross-sectional geometry, named multilobed to highlight the presence of niches and ridges. An oscillating perfusion bioreactor was used to perform bidirectional dynamic seeding of MG63 cells. The fiber shape influences the fluid dynamic parameters of the flow, affecting values of fluid velocity and wall shear stress. The path followed by cells through the scaffold fibers is also affected and results in a larger number of adhered cells in multilobed scaffolds compared to scaffolds with standard pseudo cylindrical fibers. Geometrical and fluid dynamic features can also have an influence on the morphology of adhered cells. The obtained results suggest that the reciprocal influence of geometrical and fluid dynamic features and their combined effect on cell trajectories should be considered to improve the dynamic seeding efficiency when designing scaffold architecture.

Perfusion bioreactor enabled fluid-derived shear stress conditions for novel bone metastatic prostate cancer testbed

Critical understanding of the complex metastatic cascade of prostate cancer is necessary for the development of a therapeutic interventions for treating metastatic prostate cancer. Increasing evidence supports the synergistic role of biochemical and biophysical cues in cancer progression at metastases. The biochemical factors such as cytokines have been extensively studied in relation to prostate cancer progression to the bone; however, the role of shear stress-induced by interstitial fluid around bone extracellular matrix has not been fully explored as a driving factor for prostate cancer metastasis. Shear stress governs various cellular processes, including cell proliferation and migration. Thus, it is essential to understand the impact of fluid-derived shear stress on the aggressiveness of prostate cancer at the metastatic stage. Here, we report development of a three-dimensional (3D) in-vitro dynamic cell culture system to recapitulate the microenvironment of prostate cancer bone metastasis, to understand the cause of modulation in cell response under fluid-derived shear stress. We observed an increased human mesenchymal stem cells (hMSCs) proliferation and differentiation rate under dynamic culture. We observed that hMSCs under static culture form cell agglutinates, whereas under dynamic culture, hMSCs exhibited a directional alignment with broad and flattened morphology. Next, we observed increased expression of mesenchymal to epithelial transition (MET) biomarkers in bone metastasized prostate cancer models as well as large changes in cellular and tumoroid morphologies with shear stress. Evaluation of cell adhesion proteins indicated that the altered cancer cell morphologies resulted from the constant force pulling due to increased E-Cadherin and phosphorylated Focal adhesion kinase (FAK) proteins under shear stress. Collectively, we have successfully developed a 3D in-vitro dynamic model to recapitulate the behavior of bone metastatic prostate cancer under dynamic conditions.

A comprehensive comparison of cell seeding methods using highly porous melt electrowriting scaffolds

Cell seeding is challenging in the case of additively manufactured 3-dimensional scaffolds, as the open macroscopic pore network impedes the retention of the seeding solution. The present study aimed at comparing several seeding conditions (no fetal bovine serum, 10% or 100% serum) and methods (Static seeding in Tissue Culture Treated plate (CT), Static seeding of the MES in non-Culture Treated plate (nCT), Seeding in nCT plate placed on an orbital shaker at 20 rpm (nCTR), Static seeding of the MES previously incubated with 100% FBS for 1 h to allow for protein adsorption (FBS)) commonly utilised in tissue engineering using highly porous melt electrowritten scaffolds, assessing their seeding efficacy, cell distribution homogeneity and reproducibility. Firstly, we demonstrated that the incubation in 100% serum was superior to the 10% serum pre-incubation and that 1 h only was sufficient to obtain enhanced cell attachment. We further compared this technique to the other methods and demonstrated significant and beneficial impact of the 100% serum pre-incubation, which resulted in enhanced efficacy, homogeneous cell distribution and high reproducibility, leading to accelerated colonisation/maturation of the tissue engineered constructs. We further showed the superior performance of this method using 3D-printed scaffolds also made of different polymers, demonstrating its capacity for up-scaling. Therefore, the pre-incubation of the scaffold in 100% serum is a simple yet highly effective method for enhancing cell adhesion and ensuring seeding reproducibility. This is crucial for tissue engineering applications, especially when cell availability is scarce, and for product standardisation from a translational perspective.

Tissue Engineered Esophageal Patch by Mesenchymal Stromal Cells: Optimization of Electrospun Patch Engineering

Aim of work was to locate a simple, reproducible protocol for uniform seeding and optimal cellularization of biodegradable patch minimizing the risk of structural damages of patch and its contamination in long-term culture. Two seeding procedures are exploited, namely static seeding procedures on biodegradable and biocompatible patches incubated as free floating (floating conditions) or supported by CellCrown^TM insert (fixed conditions) and engineered by porcine bone marrow MSCs (p-MSCs). Scaffold prototypes having specific structural features with regard to pore size, pore orientation, porosity, and pore distribution were produced using two different techniques, such as temperature-induced precipitation method and electrospinning technology. The investigation on different prototypes allowed achieving several implementations in terms of cell distribution uniformity, seeding efficiency, and cellularization timing. The cell seeding protocol in stating conditions demonstrated to be the most suitable method, as these conditions successfully improved the cellularization of polymeric patches. Furthermore, the investigation provided interesting information on patches’ stability in physiological simulating experimental conditions. Considering the in vitro results, it can be stated that the in vitro protocol proposed for patches cellularization is suitable to achieve homogeneous and complete cellularizations of patch. Moreover, the protocol turned out to be simple, repeatable, and reproducible.

An insight into cell-laden 3D-printed constructs for bone tissue engineering

In this review, we have spotlighted various combinations of bioinks to optimize the biofabrication of 3D bone constructs.

Osteogenic induction of human mesenchymal stem cells in multilayered electrospun scaffolds at different flow rates and configurations in a perfusion bioreactor

Electrospun scaffolds are potentially interesting in bone tissue engineering due to a strong structural similarity to the natural bone matrix. To investigate the osteogenic behavior of cells on the scaffolds, dynamic culture of cells is essential to simulate the biological environment. In the present study, human mesenchymal stem cells (hMSCs) were cultured on multilayer nanohydroxyapatite-polycaprolactone electrospun scaffolds at different configurations (horizontal with or without pressure and parallel with the medium flow) and flow rates in a perfusion bioreactor. Alkaline phosphatase (ALP) activity, cell viability, Ca deposition and RUNX2 expression were determined in three different dynamic states, and compared with static culture after 1, 3, 7, and 14 days. Among dynamic groups, RUNX2 gene expression upregulated more in a horizontal state at a low flow rate without mechanical pressure (LF) and parallel flow (PF), than static group on day 7. At a high flow rate with mechanical pressure, Ca deposition and ALP activity increased 2.34 and 1.7 folds more than in static culture over 7 days, respectively. Furthermore, ALP activity, Ca deposition and RUNX2 gene expression increased in PF samples. PF provided longer culture time with higher cell differentiation. Therefore, high flow rate with mechanical pressure and PF are suggested for producing differentiated cell structure for bone tissue engineering.

Fabrication of Scaffolds for Bone-Tissue Regeneration

The present article describes the state of the art in the rapidly developing field of bone tissue engineering, where many disciplines, such as material science, mechanical engineering, clinical medicine and genetics, are interconnected. The main objective is to restore and improve the function of bone tissue by scaffolds, providing a suitable environment for tissue regeneration and repair. Strategies and materials used in oral regenerative therapies correspond to techniques generally used in bone tissue engineering. Researchers are focusing on developing and improving new materials to imitate the native biological neighborhood as authentically as possible. The most promising is a combination of cells and matrices (scaffolds) that can be fabricated from different kinds of materials. This review summarizes currently available materials and manufacturing technologies of scaffolds for bone-tissue regeneration.

Improved osteogenic differentiation of umbilical cord blood MSCs using custom made perfusion bioreactor

Background

3D cell culture is an appropriate method to develop engineered bone tissue, where different bioreactors have been designed to mitigate the challenges in 3D culture. Currently, we tailored a perfusion reactor to witness human mesenchymal stem cells (MSCs) proliferation and differentiation over polylactic acid-polyethylene glycol (PLA/PEG) composite scaffolds.

Methods

The composite scaffolds with different weight ratios of PLA and PEG were prepared using solvent casting-particulate leaching technique. Human umbilcal card blood MSCs were cultured under dynamic and static conditions to elucidate the role of dynamic fluid flow in osteogenesis of MSCs.

Results

The human MSCs distribution over the scaffolds was confirmed with fluorescent microscopy. Alkaline phosphatase (ALP), calcium mineralization, and collagen formation were found to be higher in PLA90 scaffolds than PLA100 and PLA75. PLA90 scaffolds with better cell adhesion/proliferartion were considered for bioreactor studies and they exhibited enhanced ALP, Ca⁺² mineralization and collagen formation under dynamic perfusion than static culture. We further confirmed our observation by looking at expression levels of osteogenic marker (Runx2 and osteonectin) in differentiated MSCs subjected to perfusion culture compared to static culture.

Conclusion

The results of the current investigation once again proves that dynamic perfusion cultures improve the osteogenic differentiation of MSCs over hybrid polymer scaffolds (PLA90) for effective bone regeneration.