Fabrication Of 3D Scaffolds Research Articles

The Application of Polycaprolactone in Three-Dimensional Printing Scaffolds for Bone Tissue Engineering.

Bone tissue engineering commonly encompasses the use of three-dimensional (3D) scaffolds to provide a suitable microenvironment for the propagation of cells to regenerate damaged tissues or organs. 3D printing technology has been extensively applied to allow direct 3D scaffolds manufacturing. Polycaprolactone (PCL) has been widely used in the fabrication of 3D scaffolds in the field of bone tissue engineering due to its advantages such as good biocompatibility, slow degradation rate, the less acidic breakdown products in comparison to other polyesters, and the potential for loadbearing applications. PCL can be blended with a variety of polymers and hydrogels to improve its properties or to introduce new PCL-based composites. This paper describes the PCL used in developing state of the art of scaffolds for bone tissue engineering. In this review, we provide an overview of the 3D printing techniques for the fabrication of PCL-based composite scaffolds and recent studies on applications in different clinical situations. For instance, PCL-based composite scaffolds were used as an implant surgical guide in dental treatment. Furthermore, future trend and potential clinical translations will be discussed.

Direct 3D Printing of Seashell Precursor toward Engineering a Multiphasic Calcium Phosphate Bone Graft

Multiphasic calcium phosphate (Ca-P) has widely been explored for bone graft replacement. This study represents a simple method of developing osteoinductive scaffolds by direct printing of seashell resources. The process demonstrates a coagulation-assisted extrusion-based three-dimensional (3D) printing process for rapid fabrication of multiphasic calcium phosphate-incorporated 3D scaffolds. These scaffolds demonstrated an interconnected open porous architecture with improved compressive strength and higher surface area. Multiphasic calcium phosphate (Ca-P) and hydroxyapatite present in the multi-scalar naturally resourced scaffold displayed differential protein adsorption, thus facilitating cell adhesion, migration, and differentiation, resulting in enhanced deposition of the extracellular matrix. The microstructural and physicochemical attributes of the scaffolds also lead to enhanced stem cell differentiation as witnessed from gene and protein expression analysis. Furthermore, the histological study of subcutaneous implantation evidently portrays promising biocompatibility without foreign body reaction. Neo-tissue in-growth was manifested with abundant blood vessels, thus indicative of excellent vascularization. Notably, cartilaginous and proteoglycan-rich tissue deposition indicated ectopic bone formation via an endochondral ossification pathway. The hierarchical interconnected porous architectural tribology accompanied with multiphasic calcium phosphate composition manifests its successful implication in enhancing stem cell differentiation and promoting excellent tissue in-growth, thus making it a plausible alternative in bone tissue engineering applications.

Solution-Based Processing for Scaffold Fabrication in Tissue Engineering Applications: A Brief Review.

The fabrication of 3D scaffolds is under wide investigation in tissue engineering (TE) because of its incessant development of new advanced technologies and the improvement of traditional processes. Currently, scientific and clinical research focuses on scaffold characterization to restore the function of missing or damaged tissues. A key for suitable scaffold production is the guarantee of an interconnected porous structure that allows the cells to grow as in native tissue. The fabrication techniques should meet the appropriate requirements, including feasible reproducibility and time- and cost-effective assets. This is necessary for easy processability, which is associated with the large range of biomaterials supporting the use of fabrication technologies. This paper presents a review of scaffold fabrication methods starting from polymer solutions that provide highly porous structures under controlled process parameters. In this review, general information of solution-based technologies, including freeze-drying, thermally or diffusion induced phase separation (TIPS or DIPS), and electrospinning, are presented, along with an overview of their technological strategies and applications. Furthermore, the differences in the fabricated constructs in terms of pore size and distribution, porosity, morphology, and mechanical and biological properties, are clarified and critically reviewed. Then, the combination of these techniques for obtaining scaffolds is described, offering the advantages of mimicking the unique architecture of tissues and organs that are intrinsically difficult to design.

Double network laminarin-boronic/alginate dynamic bioink for 3D bioprinting cell-laden constructs

The design of dynamically crosslinked hydrogel bioinks for three-dimensional (3D) bioprinting is emerging as a valuable strategy to advance the fabrication of mechanically tuneable cell-laden constructs for 3D in vitro disease modelling and tissue engineering applications. Herein, a dynamic bioink comprising boronic acid-functionalised laminarin and alginate is explored for bioprinting 3D constructs under physiologically relevant conditions. The formulated bioink takes advantage of a double crosslinked network that combines covalent but reversible boronate ester bonds and ionic gelation via divalent cations. Moreover, it exhibits suitable rheological properties and improved mechanical features owing to its modular crosslinking chemistry, yielding stable constructs with user-programmable architecture. We explored such dynamic bioink as a supporting matrix for different cell classes, namely osteoblast precursors, fibroblasts and breast cancer cells. The resulting cell-laden bioprinted hydrogels display a homogeneous cell distribution post-printing and exceptional cell viability (>90%) that can be maintained for prolonged time periods in culture (14 days) for all cell lines. This simple and chemically versatile approach is envisaged to accelerate the development of multifunctional bioinks and contribute towards the fabrication of biomimetic 3D scaffolds with applicability in a wide range of predictive or exploratory biomedical platforms.

Structure-function assessment of 3D-printed porous scaffolds by a low-cost/open source fused filament fabrication printer

Additive manufacturing encompasses a plethora of techniques to manufacture structures from a computational model. Among them, fused filament fabrication (FFF) relies on heating thermoplastics to their fusion point and extruding the material through a nozzle in a controlled pattern. FFF is a suitable technique for tissue engineering, given that allows the fabrication of 3D-scaffolds, which are utilized for tissue regeneration purposes. The objective of this study is to assess a low-cost/open-source 3D printer (In-House), by manufacturing both solid and porous samples with relevant microarchitecture in the physiological range (100–500 μm pore size), using an equivalent commercial counterpart for comparison. For this, compressive tests in solid and porous scaffolds manufactured in both printers were performed, comparing the results with finite element analysis (FEA) models. Additionally, a microarchitectural analysis was done in samples from both printers, comparing the measurements of both pore size and porosity to their corresponding computer-aided design (CAD) models. Moreover, a preliminary biological assessment was performed using scaffolds from our In-House printer, measuring cell adhesion efficiency. Finally, Fourier transform infrared spectroscopy – attenuated total reflectance (FTIR–ATR) was performed to evaluate chemical changes in the material (polylactic acid) after fabrication in each printer. The results show that the In-House printer achieved generally better mechanical behavior and resolution capacity than its commercial counterpart, by comparing with their FEA and CAD models, respectively. Moreover, a preliminary biological assessment indicates the feasibility of the In-House printer to be used in tissue engineering applications. The results also show the influence of pore geometry on mechanical properties of 3D-scaffolds and demonstrate that properties such as the apparent elastic modulus (Eapp) can be controlled in 3D-printed scaffolds.

Boosting in vitro cartilage tissue engineering through the fabrication of polycaprolactone-gelatin 3D scaffolds with specific depth-dependent fiber alignments and mechanical stimulation

Due to the limited self-healing ability of natural cartilage, several tissue engineering strategies have been explored to develop functional replacements. Still, most of these approaches do not attempt to recreate in vitro the anisotropic organization of its extracellular matrix, which is essential for a suitable load-bearing function. In this work, different depth-dependent alignments of polycaprolactone-gelatin electrospun fibers were assembled into three-dimensional scaffold architectures to assess variations on chondrocyte response under static, unconfined compressed and perfused culture conditions. The in vitro results confirmed that not only the 3D scaffolds specific depth-dependent fiber alignments potentiated chondrocyte proliferation and migration towards the fibrous systems, but also the mechanical stimulation protocols applied were able to enhance significantly cell metabolic activity and extracellular matrix deposition, respectively.

Integrated Design Strategy for Additively Manufactured Scaffolds in Tissue Engineering

AbstractAdditive manufacturing technologies allow for the direct fabrication of 3D scaffolds with improved properties for tissue regeneration. In this scenario, design strategies and 3D fiber deposition technique are considered to develop advanced scaffolds with different lay‐down patterns, tailored mechanical and biological properties. 3D poly(ε‐caprolactone) scaffolds are manufactured and surface‐modified (i.e., aminolysis). The effect of surface modification on the mechanical and biological performances of the designed 3D scaffolds is assessed.

Zein as a versatile biopolymer: different shapes for different biomedical applications.

In recent years, the interest regarding the use of proteins as renewable resources has deeply intensified. The strongest impact of these biomaterials is clear in the field of smart medicines and biomedical engineering. Zein, a vegetal protein extracted from corn, is a suitable biomaterial for all the above-mentioned purposes due to its biodegradability and biocompatibility. The controlled drug delivery of small molecules, fabrication of bioactive membranes, and 3D assembly of scaffold for tissue regeneration are just some of the topics now being extensively investigated and reported in the literature. Herein, we review the recent literature on zein as a biopolymer and its applications in the biomedical world, focusing on the different shapes and sizes through which it can be manipulated.

Fabrication of 3D Scaffolds Displaying Biochemical Gradients along Longitudinally Oriented Microchannels for Neural Tissue Engineering.

Biochemical and physical guidance cues are both pivotal for axonal guidance and nerve regeneration. However, fabrication of a platform that can integrate biochemical gradients and topographical guidance cues remains challenging, especially in a three-dimensional (3D) scaffold that closely mimics in vivo axonal outgrowth conditions and ready to be used for in vivo nerve repair. In this study, a new method was introduced to construct 3D scaffolds displaying continuous biochemical gradients along longitudinally oriented microchannels by combining the modified 3D printing and directional freezing techniques. Fluorescence analysis and ELISA results demonstrated that a continuous biochemical gradient was formed, and scanning electron microscopy revealed a longitudinally oriented microstructure. Dorsal root ganglia explants seeded on the longitudinal sections of the newly developed scaffold (scaffold with nerve growth factor gradient along oriented microstructure, G-NGF + OS) showed that 81.3 ± 4.5% of neurites oriented within ±10°, 0.3 ± 0.1 of guidance ratio, and 1.5-fold of the average length of neurites on the high-nerve growth factor (NGF) concentration side compared to that on the low-NGF concentration side, which were significantly higher than those in the other groups. In addition, the G-NGF + OS scaffold was used to repair a 15 mm sciatic nerve defect in rats. Immunofluorescence staining, Fluoro-Gold retrograde tracing, and transmission electron microscopy results confirmed that the G-NGF + OS scaffold enhanced nerve regeneration to the distal target and promoted myelination of regenerated axons. More importantly, the sciatic functional index and the von Frey test demonstrated that the G-NGF + OS scaffold accelerated sensory and motor functional recovery. These results provide new insights into the importance of combining topographical guidance cues with bioactive molecule gradient cues for neural tissue engineering. The 3D scaffold displaying biochemical gradients along longitudinally oriented microchannels represents a promising platform for the development of advanced devices for severe nervous system injuries.

Electroless Deposition of Ni-Fe Alloys on Scaffolds for 3D Nanomagnetism.

3D magnetic nanostructures are of great interest due to the possibility to design novel properties and the benefits for both technological applications such as high-density data storage, as well as more fundamental studies. One of the main challenges facing the realization of these three-dimensional systems is their fabrication, which includes the deposition of magnetic materials on 3D surfaces. In this work, the electroless deposition of Ni-Fe on a 3D-printed, non-conductive microstructure is presented. The deposited films exhibit low coercivity, with the saturation magnetization and composition corresponding to the archetypal soft magnetic material permalloy. For fundamental studies of 3D micromagnetism, this new development in fabrication offers the possibility to combine the flexibility of 3D nanofabrication techniques such as two-photon lithography for the fabrication of 3D scaffolds with a homogeneous soft ferromagnetic thin film, and thus represents an important step toward exploring the rich physics of complex 3D magnetic architectures with tailored properties and the development of advanced applications.

Fabrication of strontium-substituted hydroxyapatite scaffolds using 3D printing for enhanced bone regeneration

The use of porous three-dimensional (3D) bioceramic scaffolds to facilitate the regeneration of bone defects has attracted great attention because their structures closely mimic the natural extracellular matrix. 3D printing is a versatile method for the fabrication of 3D scaffolds. In this study, 3D strontium-substituted hydroxyapatite (Sr-HA) bioceramic scaffolds were prepared by simple precipitation and 3D printing method. The resulting scaffolds exhibited interconnected microporous structures of strands and a single-phase crystal due to HA, meaning that no changes in the phase composition and microstructure of the scaffolds with the Sr content were observed. However, their dissolution rate and biological performance were substantially influenced by changes in the Sr content of the scaffolds. The optimal Sr content in the Sr-HA scaffolds for enhanced proliferation and differentiation of cells were identified by comparing four compositions of the Sr-HA scaffolds. The results of in vitro bioactivity tests demonstrated that the Sr5-HA scaffold with 0.05 of Sr/(Ca + Sr) molar ratio promoted more rapid cell proliferation, osteogenic differentiation, and cellular mineralization compared with the other scaffolds. Therefore, Sr-HA scaffolds have the potential for application in bone regeneration as new bone graft substitutes.

4D printing of self-folding and cell-encapsulating 3D microstructures as scaffolds for tissue-engineering applications

Technology of tissue-engineering advanced rapidly in the last decade and motivated numerous studies in cell-engineering and biofabrication. Three-dimensional (3D) tissue-engineering scaffolds play a critical role in this field, as the scaffolds provide the biomimetic microenvironments that could stimulate desired cell behaviors for regeneration. However, despite many achievements, the fabrication of 3D scaffold remains challenging due to the difficulty of encapsulating cells in 3D scaffolds, controlling cell-cell organization in 3D, and being adapted by users unfamiliar with 3D biofabrication. In this study, we circumvent these obstacles by creating a four-dimensional (4D) inkjet-printing platform. This platform produces micropatterns that self-fold into a 3D scaffold. Seeding live cells uniformly onto the micropatterns before self-folding leads to cell-encapsulating 3D scaffolds with layer-wise cell-cell organization. Photo-crosslinkable biomaterial-inks of distinct swelling rates were synthesized from gelatin, and the biomaterial-inks were patterned by a customized high-precision inkjet-printer into bilayer micropatterns that were capable of self-folding into 3D microstructures. A mathematical model was developed to help design self-folding and to aid the understanding of the self-folding mechanism. Human umbilical vein endothelial cells (HUVECs) were embedded in self-folded microtubes to mimic microvessels. HUVECs in the microtube spread, proliferated, showed high cell viability, and engrafted on the microtube’s inner wall mimicking the native endothelial cells. For physician and biologist end-users, this 4D printing method provides an easy-to-use platform that supports standard two-dimensional cell-seeding protocol while enabling the users to customize 3D cellularized scaffold as desired. This work demonstrated 4D printing as a promising tool for tissue-engineering applications.

Robust Fabrication of Composite 3D Scaffolds with Tissue-Specific Bioactivity: A Proof-of-Concept Study.

The basic requirement of any engineered scaffold is to mimic the native tissue extracellular matrix (ECM). Despite substantial strides in understanding the ECM, scaffold fabrication processes of sufficient product robustness and bioactivity require further investigation, owing to the complexity of the natural ECM. A promising bioacive platform for cardiac tissue engineering is that of decellularized porcine cardiac ECM (pcECM, used here as a soft tissue representative model). However, this platform's complexity and batch-to-batch variability serve as processing limitations in attaining a robust and tunable cardiac tissue-specific bioactive scaffold. To address these issues, we fabricated 3D composite scaffolds (3DCSs) that demonstrate comparable physical and biochemical properties to the natural pcECM using wet electrospinning and functionalization with a pcECM hydrogel. The fabricated 3DCSs are non-immunogenic in vitro and support human mesenchymal stem cells' proliferation. Most importantly, the 3DCSs demonstrate tissue-specific bioactivity in inducing spontaneous cardiac lineage differentiation in human induced pluripotent stem cells (hiPSC) and further support the viability, functionality, and maturation of hiPSC-derived cardiomyocytes. Overall, this work illustrates the technology to fabricate robust yet tunable 3D scaffolds of tissue-specific bioactivity (with a proof of concept provided for cardiac tissues) as a platform for basic materials science studies and possible future R&D application in regenerative medicine.

Three-dimensional porous composite scaffolds for in vitro marrow microenvironment simulation to screen leukemia drug

The traditional 2D culture medium used for simulating the in vitro microenvironment for leukemia cells usually leads to 95% of the drug test results being different to the subsequent clinical results. Unlike this 2D culture, 3D scaffolds are more similar to the bone marrow microenvironment so can better simulate the drug effect on leukemia cells, which can benefit the preliminary screening of drugs for clinical use. For this purpose, the freeze-drying method was proposed for the fabrication of 3D scaffolds of graphene oxide/silk fibroin/carboxymethyl chitosan (GO/SF/CMCS). Experimental results show that these 3D scaffolds exhibit a better swelling ratio because of the embedding of GO. The improved hydrophilicity of the scaffolds brings about promoted adhesion and proliferation of leukemia cells. In contrast to the traditional 2D culture, leukemia cells in this 3D culture show stronger drug resistance, which is consistent with the previously reported clinical results. It implies that these 3D GO/SF/CMCS scaffolds can simulate well the in vivo bone marrow microenvironment, making it a promising platform for preliminary drug screening for clinical use.

Fabrication of calcium phosphate 3D scaffolds for bone repair using magnetic levitational assembly

The calcium phosphate particles can be used as building blocks for fabrication of 3D scaffolds intended for bone tissue engineering. This work presents for the first time a rapid creation of 3D scaffolds using magnetic levitation of calcium phosphate particles. Namely, tricalcium phosphate particles of equal size and certain porosity are used, which undergo the process of recrystallization after magnetic levitational assembly of the scaffold to ensure stitching of the scaffold. Label-free levitational assembly is achieved by using a custom-designed magnetic system in the presence of gadolinium salts, which allows the levitation of calcium phosphate particles. Chemical transformation of tricalcium- to octacalcium phosphate under the condition of magnetic levitation in non-homogeneous magnetic field is also demonstrated. This approach allows obtaining rapidly the octacalcium phosphate phase in the final 3D product, which is biocompatible.

Abstract P3-02-11: Topographical ues overlaid with fructose-like molecules to assess breast cancer recruitment in nanofiber scaffolds

Abstract Tumorigenesis is a complex process involving numerous cellular signaling cascades and environmental factors. While 2D cultures for stiffness measurements and more recently 3D cultures to demonstrate differences in cell structures have been reported, very little is known about the impact of sugars in cell recruitment. In this study, we report the fabrication of 3D-scaffolds with different morphologies obtained by electrospinning with fluorescent fructose-like molecular probes to study cancer cell proliferation and migration. Using a FDA approved, biocompatible and biodegradable polymer Polycaprolactone (PCL), we electrospun nanofiber scaffolds having random, aligned, and honeycomb morphologies. Scaffolds with similar morphology without the fructose mimicking analogs were fabricated and used as controls. The degradation rate of the scaffolds was also characterized to ensure long-term availability of probes and mechanical stability of PCL. Cell viability, cell morphology, formation of colonies with changes in morphology were investigated. The changes in biophysical properties of tumor microenvironment with change in morphology of the scaffolds were investigated. In vitro tests for proliferation, alignment and migration of normal breast epithelial cells (184B5), adenocarcinoma (MCF-7), pre-malignant (MCF10AneoT) and triple-negative (MDAMB231 on the scaffolds on days 1, 2, and 3 were carried out. The morphology of the scaffolds was characterized using FE-SEM; cell proliferation was assessed using CellTiter-Blue® Viability Assay; migration and cell-scaffold interactions were investigated using phalloidin for F-Actin and fructose response was determined by immunostaining for facilitative fructose transporter GLUT-5. Our data indicates that while topographical features affected cell adhesion and proliferation, cell lines that responded to the fructose-like probes tended to be more invasive. Furthermore, the preference to a specific scaffold was greatly altered by the presence of the probes with MDAMB231 showing least preference after 72 hours and pre-malignant AneoT showing highest preference. However, there was no significant difference in the cell numbers between scaffolds with probes and those without for the pre-malignant cells while this difference was noticeable in the control cell lines. Further investigation into specific response to glucose and fructose uptake through their major transporters GLUT2 and GLUT5 are currently ongoing. Citation Format: Carolynn Que, Samerender Nagam Hanumantharao, Brennan Vogl, Marina Tanasova, Smitha Rao. Topographical ues overlaid with fructose-like molecules to assess breast cancer recruitment in nanofiber scaffolds [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P3-02-11.

Controlling Fluid Diffusion and Release through Mixed-Molecular-Weight Poly(ethylene) Glycol Diacrylate (PEGDA) Hydrogels.

Due to their inherent ability to swell in the presence of aqueous solutions, hydrogels offer a means for the delivery of therapeutic agents in a range of applications. In the context of designing functional tissue-engineering scaffolds, their role in providing for the diffusion of nutrients to cells is of specific interest. In particular, the facility to provide such nutrients over a prolonged period within the core of a 3D scaffold is a critical consideration for the prevention of cell death and associated tissue-scaffold failure. The work reported here seeks to address this issue via fabrication of hybrid 3D scaffolds with a component fabricated from mixed-molecular-weight hydrogel formulations capable of storing and releasing nutrient solutions over a predetermined time period. To this end, poly(ethylene) glycol diacrylate hydrogel blends comprising mixtures of PEGDA-575 Mw and PEGDA-2000 Mw were prepared via UV polymerization. The effects of addition of the higher-molecular-weight component and the associated photoinitiator concentration on mesh size and corresponding fluid permeability have been investigated by diffusion and release measurements using a Theophylline as an aqueous nutrient model solution. Fluid permeability across the hydrogel films has also been determined using a Rhodamine B solution and associated fluorescence measurements. The results indicate that addition of PEGDA-2000 Mw to PEGDA-575 Mw coupled with the use of a specific photoinitiator concentration provides a means to change mesh size in a hydrogel network while still retaining an overall microporous material structure. The range of mesh sizes created and their distribution in a 3D construct provides for the conditions required for a more prolonged nutrient release profile for tissue-engineering applications.

Fabrication of 3D scaffolds reproducing intestinal epithelium topography by high-resolution 3D stereolithography

The small intestine is a complex tissue with a crypt/villus architecture and high tissue polarity. Maintenance of tissue integrity and function is supported by a constant renewal of the epithelium, with proliferative cells located in the crypts and differentiated cells migrating upward to the top of villi. So far, most in vitro studies have been limited to 2D surfaces or 3D organoid cultures that do not fully recapitulate the tissue 3D architecture, microenvironment and cell compartmentalization found in vivo. Here, we report the development of a 3D model that reproduces more faithfully the architecture of the intestinal epithelium in vitro. We developed a new fabrication process combining a photopolymerizable hydrogel that supports the growth of intestinal cell lines with high-resolution stereolithography 3D printing. This approach offers the possibility to create artificial 3D scaffolds matching the dimensions and architecture of mouse intestinal crypts and villi. We demonstrate that these 3D culture models support the growth and differentiation of Caco-2 cells for 3 weeks. These models may constitute a complementary approach to organoid cultures to study intestinal homeostasis by allowing guided self-organization and controlled differentiation, as well as for in vitro drug screening and testing.

Fabrication and multiscale characterization of 3D silver containing bioactive glass-ceramic scaffolds

In this work, we fabricated and characterized bioactive 3D glass-ceramic scaffolds with inherent antibacterial properties. The sol-gel (solution-gelation) technique and the sacrificial template method were applied for the fabrication of 3D highly porous scaffolds in the 58.6SiO2 - 24.9CaO - 7.2P2O5 - 4.2Al2O3 – 1.5Na2O −1.5K2O – 2.1Ag2O system (Ag-BG). This system is known for its advanced bioactive and antibacterial properties. The fabrication of 3D scaffolds has potential applications that impact tissue engineering. The study of the developed scaffolds from macro-characteristics to nano-, revealed a strong correlation between the macroscale properties such as antibacterial action, bioactivity with the microstructural characteristics such as elemental analysis, crystallinity. Elemental homogeneity, morphological, and microstructural characteristics of the scaffolds were studied by scanning electron microscopy associated with energy dispersive spectroscopy (SEM-EDS), transmittance electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and UV-visible spectroscopy methods. The compressive strength of the 3D scaffolds was measured within the range of values for glass-ceramic scaffolds with similar compositions, porosity, and pore size. The capability of the scaffolds to form an apatite-like phase was tested by immersing the scaffolds in simulated body fluid (SBF) and the antibacterial response against methicillin-resistant Staphylococcus aureus (MRSA) was studied. The formation of an apatite phase was observed after two weeks of immersion in SBF and the anti-MRSA effect occurs after both direct and indirect exposure.

A Study on the Fabrication of 3D Scaffolds Using the Solid Freeform Method

A Study on the Fabrication of 3D Scaffolds Using the Solid Freeform Method