Direct ink writing of vancomycin-loaded polycaprolactone/ polyethylene oxide/ hydroxyapatite 3D scaffolds

Novel inks were formulated by dissolving polycaprolactone (PCL), a hydrophobic polymer, in organic solvent systems; polyethylene oxide (PEO) was incorporated to extend the range of hydrophilicity of the system. Hydroxyapatite (HAp) with a weight ratio of 55–85% was added to the polymer-based solution to mimic the material composition of natural bone tissue. The direct ink writing (DIW) technique was applied to extrude the formulated inks to fabricate the predesigned tissue scaffold structures; the influence of HAp concentration was investigated. The results indicate that in comparison to other inks containing HAp (55%, 75%, and 85%w/w), the ink containing 65% w/w HAp had faster ink recovery behavior; the fabricated scaffold had a rougher surface as well as better mechanical properties and wettability. It is noted that the 65% w/w HAp concentration is similar to the inorganic composition of natural bone tissue. The elastic modulus values of PCL/PEO/HAp scaffolds were in the range of 4–12 MPa; the values were dependent on the HAp concentration. Furthermore, vancomycin as a model drug was successfully encapsulated in the PCL/PEO/HAp composite scaffold for drug release applications. This paper presents novel drug-loaded PCL/PEO/HAp inks for 3D scaffold fabrication using the DIW printing technique for potential bone scaffold applications.     

Investigation of oleic acid as a dispersant for hydroxyapatite powders for use in ceramic filled photo-curable resins for stereolithography

Stereolithography allows production of porous hydroxyapatite scaffolds for bone regeneration but is limited by the challenging rheology of ceramic filled resins. Oleic acid, a natural fatty acid, was applied in concentrations of 0.0–0.3 wt% to improve the rheological properties of HAp resins for the fabrication of solid cylinders and scaffolds by digital light processing (DLP) printing in a wiperless system. Bonding by chemisorption was confirmed by FTIR analysis. The powders were then incorporated into a photo-curable resin of 1–6 hexanediol diacrylate at 18–30 vol%. The shear viscosity and sedimentation rates of photocurable resins containing HAp powder decreased with increasing concentration of oleic acid. The curing depth and width of resins containing the HAp were unchanged as a result of the presence of oleic acid. Oleic acid improved the printing behaviour of the resins allowing the fabrication of scaffolds with continuous macro-porosity on a wiperless DLP system.     

Effects of pore size on the mechanical and biological properties of stereolithographic 3D printed HAp bioceramic scaffold

In this study, hydroxyapatite (HAp) scaffolds with the pore size of 400, 500, and 600 μm were prepared by stereolithographic 3D printing (SL-3DP). The effects of pore size on mechanical and biological properties of the HAp scaffolds were investigated. Firstly, the macro- and microstructure of the HAp scaffolds were observed. Then, the compressive strength of the HAp scaffolds were tested. Finally, the biological properties of the HAp scaffolds were further characterized in vitro by the synthetic body fluid (SBF) solution immersion testing, as well as by using the cell proliferation and 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. From this study, it was found that the HAp scaffold with a pore size of 600 μm had the most promising application prospect.     

Preparation and characterization of Chitosan and PLGA‐based scaffolds for tissue engineering applications

Three dimensional (3D) biodegradable porous scaffolds play a crucial role in bone tissue repair. In this study, four types of 3D polymer/hydroxyapatite (HAp) composite scaffolds were prepared by freeze drying technique in order to mimic the organic/inorganic nature of the bone. Chitosan (CH) and poly(lactic acid‐co‐glycolic acid) (PLGA) were used as the polymeric part and HAp as the inorganic component. Properties of the resultant scaffolds, such as morphology, porosity, degradation, water uptake, mechanical and thermal stabilities were examined. 3D scaffolds having interconnected macroporous structure and 77–89% porosity were produced. The pore diameters were in the range of 6 and 200 µm. PLGA and HAp containing scaffolds had the highest compressive modulus. PLGA maintained the strength by decreasing water uptake but increased the degradation rate. Scaffolds seeded with SaOs‐2 osteoblast cells showed that all scaffolds were capable of encouraging cell adhesion and proliferation. The presence of HAp particles caused an increase in cell number on CH‐HAp scaffolds compared to CH scaffolds, while cell number decreased when PLGA was incorporated in the structure. CH‐PLGA scaffolds showed highest cell number on days 7 and 14 compared to others. Based on the properties such as interconnected porosity, high mechanical strength, and in vitro cell proliferation, blend scaffolds have the potential to be applied in hard tissue treatments. POLYM. COMPOS., 36:1917–1930, 2015. © 2014 Society of Plastics Engineers     

Effect of graphene reinforcement on hybrid bioceramic coating deposited on the produced porous Ti64 alloys

Porous-Ti64 alloys (P-Ti64), produced at various porosities by hot-pressing technique with the help of Mg spacer, were coated by hybrid-Graphene Oxide (rGO) reinforced-hydroxyapatite (HAp), using the sol–gel method. The synthesized rGO powder was used in reinforcing HAp by the Modified Hummers method having 30 µm particle size and nano (nm) scale layer thickness. Hybrid coatings were executed on Ti64 substrates in four different groups as single-HAp, HAp reinforced with 0.5 wt%, 1.0 wt% and 1.5 wt% rGO for three different porosities (41, 52, and 64%) were characterized by FT-IR, Raman, XRD and SEM. The average 21 µm coating film thicknesses were obtained and desirably, the only superficial pores of the substrates were closed by coating material rather than the inner connected open pores. It was also shown that 0.5 wt% and 1.0 wt% rGO reinforcements into HAp prevented crack formation on the Ti64 surfaces, whereas 1.5 wt% rGo reinforcement and single-HAp coatings caused. The highest adhesion strength values were achieved at low porosities (41–52%) and of 0.5–1.0 wt% rGO reinforcements through the adhesion tests.

     

LAS glass–ceramic scaffolds by three-dimensional printing

Highly porous (>60% open porosity) glass–ceramic scaffolds with remarkable mechanical properties (compression strength of ～15 MPa) were produced by indirect 3D printing. Precursor glass powders were printed into 3D ordered structures and then heat treated to sinter and develop crystalline phases. The final glass–ceramic contained a β-spodumene solid solution together with a secondary phase of lithium disilicate.The precision of the printed geometry and the density of the struts in the scaffold depended on several processing parameters (e.g. powder size and flowability, layer thickness) and were improved by increasing the binder saturation and drying time. Two types of powders with different particle size distribution (PSD) and flowability were used. Powders with a larger PSD, could be processed within a wider range of printing parameters due to their good flowability; however, the printing precision and the struts density were lower compared to the scaffolds printed using the powder in a smaller average PSD.     

Synthesis of ultralong hydroxyapatite micro/nanoribbons and their application as reinforcement in collagen scaffolds for bone regeneration

Ultralong hydroxyapatite (HAp) micro/nanoribbons were successfully synthesized by a simple hydrothermal method without using any organic solvents and templates. The ultralong HAp micro/nanoribbons were up to several hundred micrometers in length and 100–400?nm in width. The growth process and mechanism of this micro/nanoribbons were also analyzed in this study. Moreover, the ultralong HAp micro/nanoribbons were used as reinforcement in collagen scaffolds and the HAp/collagen composite scaffolds were fabricated by freeze-drying process without cross-linking. The morphological results demonstrated homogeneous interconnected porous structure in 20?wt% and 35?wt% HAp reinforced scaffolds. The compressive modulus of the 35?wt% HAp/collagen composite was about 6 times that of the pure collagen scaffold. The ultralong HAp reinforced collagen scaffold possesses a porous structure, good flexibility as well as elasticity, and thus it is promising for used as bone repair material.     

Modification of hydroxyapatite (HA) powder by carboxymethyl chitosan (CMCS) for 3D printing bioceramic bone scaffolds

The poor mechanical properties of 3D printed HA bone scaffold is always a challenge in tissue engineering, to address this issue, carboxymethyl chitosan (CMCS) was proposed to modify HA bone scaffolds by a physical blending method in this research. A series of HA and HA/CMCS composite ceramic scaffolds were printed by using piezoelectric inkjet 3D printing technology, and their properties were investigated in terms of forming quality, structural morphology, mechanical properties, degradability, cytotoxicity, and cell adhesion growth. The results of forming quality and structural morphology show that with the increase of CMCS content, the forming quality of the samples deteriorated, the pore size and porosity increased. However, when the content of CMCS reached 5 wt%, obvious cracks appeared on the surface of the sample, and the forming quality was relatively poor. The mechanical testing results indicated the toughness of composites could be enhanced by incorporating CMCS into HA, which was attributed to the higher strength connections of the CMCS polymer network between HA particles and the stronger interaction between HA and CMCS molecules. FTIR spectra further revealed the strong hydrogen bonding interaction between CMCS and HA. Moreover, the degradation rate and mineralization ability of the sample increased with the content of CMCS, but the compressive strength during degradation increased with the CMCS content, indicating that incorporating CMCS into HA cannot only improve the mechanical property and biological activity of the scaffold but also makes up the defect of slow degradation of pure HA scaffold. Finally, the cytotoxicity, cell adhesion, and cell proliferation tests show that HA and HA/CMCS composite samples had good cytocompatibility, HA/CMCS sample with 3 wt% CMCS possessed the best bioactivity. In summary, HA/CMCS composite powder with 3 wt% CMCS content is the optimal matrix material for 3D printing bone scaffolds.     

Rapid microwave-assisted synthesis of gold loaded hydroxyapatite collagen nano-bio materials for drug delivery and tissue engineering application

A rapid microwave assisted facile synthetic technique was adopted to load gold nanoparticles (Au) on hydroxyapatite (HAp) surface. HAp nanoparticles were primarily synthesized by wet precipitation technique and further used for gold loading and successive collagen coating for biomedical applications. The microwave-assisted controlled synthesis technique with three heating cycles allows the very fast growing of Au seeds over HAp facets. Different sophisticated analytical techniques and spectroscopic characterization were employed to confirm the structural, chemical, and morphological features. The synthesized different concentration “Au” loaded hetero nanostructures coated with collagen (Au–HAp–Col) optimized for drug (Doxorubicin: DOX) loading and releasing purposes for biomedical applications. The maximum drug-loading efficiency of ~58.22% and a pH responsive releasing of ~53% (at pH 4.5) was obtained for 0.1?wt% Au–HAp–Col nanoparticles. To study the cytotoxic effects from the hetero nanostructures, MG-63 osteoblast-like cells were exposed to different concentration ranges on Au–HAp, Au–HAp–Col, and DOX loaded Au–HAp–Col nanoparticles. The non-toxic and bioactive properties of the synthesized nanoparticle-fabricated scaffold promotes cellular attachment, growth, and proliferation. These results indicated that optimized Au–HAp–Col nanoparticles may be promising drug delivery and scaffold materials for multifunctional biomedical applications.     

The effect of filler content on mechanical properties and cell response of elastomeric PGS/apatite foam scaffolds

Poly(glycerol sebacate) (PGS) is a novel polymeric material intended for applications in tissue engineering (TE). This study involves synthesizing the PGS prepolymer (pPGS) and subsequent manufacturing of porous PGS-based scaffolds with an addition of hydroxyapatite (HAp) by means of thermally induced phase separation followed by thermal cross-linking and salt-leaching (TIPS-TCL-SL). The study aims to investigate the effect of the apatite filler content on properties and morphology of porous PGS/HAp scaffolds. The emphasis is put on the mechanical behavior of the material characterized by means of compression tests and dynamic thermal mechanical analysis (DMTA). In addition to the reference polymer scaffold, the composites with filler contents of 10, 20 and 30 wt% have been examined. Our research revealed that the HAp content does not affect the mechanical properties in a directly proportional manner. The 30 wt% addition of HAp resulted in frayed structure and decrease in the mechanical parameters in comparison to other tested specimens. On the other hand, an addition of 10% did not sufficiently boost the properties. Therefore, a 20% addition of HAp was concluded to have superior mechanical properties in comparison to other analyzed specimens. A similar relationship results from the DMTA studies. Moreover, the strain sweep and frequency sweep tests confirmed the stability of the mechanical parameters in various conditions, as well as the elastomeric nature of the materials. Finally, the material did not exhibit cytotoxicity against standard L929 fibroblasts and cells readily populated the scaffolds.     

Controlled anisotropy in 3D printing of silica-based ceramic cores through oxidization reaction of aluminum powders

Ceramic cores are key components to form inner hollow structures in aero-engine blades, and 3D printing is an ideal molding technology for ceramic cores. In this work, silica-based ceramic cores are fabricate via 3D printing of digital light processing (DLP) stereolithography, and the anisotropy in microstructure and property are controlled by aluminum powders. The ceramic cores without aluminum powders exhibit anisotropic microstructure with interlayer gaps, which get narrower and disappear with doping of 7.5–10 wt% of aluminum powders, due to the volume expansion during oxidization reaction of aluminum powders filling the interlayer gaps. The anisotropy in mechanical property is rely on the printing direction, and the ratio of strength in different directions (σ_V/σ_H) is put forward to value the mechanical anisotropy; the ratios rise from 0.40 to 0.92 at room temperature and 0.51 to 0.97 at 1540 °C, as 7.5 wt% of aluminum is doped, and the optimized ceramic cores show high-temperature strengths of 16.6 MPa and 16.1 MPa in different printing directions. Even though ceramic cores with 10 wt% of aluminum show uniform microstructure and higher σ_V/σ_H ratio, the weak particle bonding within printing layers limits their mechanical property, and the strengths decrease to 13.8 MPa and 13.4 MPa at 1540 °C. This work inspires a new technique to excellent high-temperature mechanical properties with anisotropy control in 3D printing of ceramic cores.     

Mechanical properties and biocompatibility of MgO / Ca3(PO4)2 composite ceramic scaffold with high MgO content based on digital light processing

Magnesium oxide-calcium phosphate (MgO/Ca3(PO4)2) composite ceramic materials are considered a promising class of bioactive materials, expected to be used in artificial bone scaffolds. However, there are few pieces of research on the content of magnesium oxide in composite ceramic scaffolds. To study the effect of magnesium oxide content on the biocompatibility and mechanical properties of magnesium oxide-calcium phosphate composite ceramic scaffolds, six groups of scaffolds with magnesium oxide content of 10 wt%, 20 wt%, 30 wt%, 40 wt%, 100 wt%, and 0 wt% were produced by digital light processing (DLP) printing technology. And scaffolds’ pores size and porosity percentage were 0.6–1 mm and 50%, respectively. The compressive strength of the scaffold increased with the magnesium oxide proportion, and the 40 wt% group was almost twice that of the 0 wt% magnesium oxide group. The 40 wt% and 0 wt% magnesium oxide groups performed better for biocompatibility. Comprehensive analysis of the biocompatibility and mechanical properties of the scaffold confirmed that the 40 wt% magnesium oxide group was the best. The results show that high magnesium oxide content enhanced the mechanical properties and achieved well biocompatibility of the composite scaffolds, broadening the scope of future experimental research.     

3D printing of cordierite materials from raw reactive mixtures

Porous cordierite materials are 3D printed by robocasting from two kaolin containing raw materials mixtures. Water suspensions of both mixtures at variable solid concentrations (40–67 wt%) are characterized by rheological measurements, showing good printability for concentrations >60 wt% without the need of any printing additive. The mixtures react during sintering (at 1250 °C) giving indialite as the main phase in the structures, which differ in minor phases. Three types of lattices are printed for both compositions with a logpile inner structure. Properties of interest like the coefficient of thermal expansion (CTE), the thermal conductivity (K_T) and the compression strength (σ) of the printed cordierites are determined and compared with published data. Results evidence that printing of clay containing reactive mixtures is a straightforward and cost-effective way to achieve porous complex shaped cordierite with CTE～ 2–3 x10^?6 K^-1, K_T ～ 0.4–0.6 W m^?1 K^?1 and maximum σ of 24 MPa.     

Highly filled poly(l-lactic acid)/hydroxyapatite composite for 3D printing of personalized bone tissue engineering scaffolds

The designing of new biodegradable polymer composites is one of the most promising areas of modern orthopedics and regenerative surgery. At present, a number of methods have been proposed for designing and processing biodegradable polymer composites via various 3D printing technologies; however, the homogeneity of filler distribution together with mechanical properties of scaffolds made of such composites are far from those required for clinical use. In this study, the method for producing biodegradable composite material based on poly(l -lactic acid) (PLLA) solution in organic solvent and hydroxyapatite (HAp) powder was proposed. The influence of HAp weight fraction and additional annealing on PLLA matrix crystallinity was investigated. It was shown that crystallinity of PLLA decreases from 58.84 ± 1.21 to 17.33 ± 1.69 as HAp weight fraction increased from 0 to 50 wt%. However, HAp filler promoted PLLA crystallites growth according to the X-ray powder diffraction analysis. The results of nanoindentation showed Young's modulus values of the 3D-printed scaffolds with 50 wt% of HAp at the level of human femur and tibia.     

Adsorption of cationic dyes within spherical particles of poly(N-isopropylacrylamide) hydrogel containing smectite

Spherical particle of poly(N-isopropylacrylamide) hydrogel containing smectite clay (a synthetic saponite) was prepared by the polymerization of N-isopropylacrylamide in aqueous clay suspension. The diameter of the gel particle is 800–1300 nm and the clay content is 11 wt.% (clay/poly(N-isopropylacrylamide)). The gel particle was shown to be useful adsorbent of cationic species from water as a result of strong electrostatic interactions between smectites and the cationic species. Due to the fact that the cation adsorption capacity to the present hybrid hydrogel particles is determined by the cation exchange capacity of clay, the hydrogel particles containing clay are a useful scaffold to immobilize various cationic species to construct functional hybrid gel particles.     

Enhanced mechanical properties of 3D printed alumina ceramics by using sintering aids

Stereolithography based 3D printing provides an efficient pathway to fabricate alumina ceramics, and the exploration on the mechanical properties of 3D printed alumina ceramics is crucial to the development of 3D printing ceramic technology. However, alumina ceramics are difficult to sinter due to their high melting point. In this work, alumina ceramics were prepared via stereolithography based 3D printing technology, and the improvement in the mechanical properties was investigated based on the content, the type and the particle size of sintering aids (TiO₂, CaCO₃, and MgO). The flexural strength of the sintered ceramics increased greatly (from 139.2 MPa to 216.7 MPa) with the increase in TiO₂ content (from 0.5 wt% to 1.5 wt%), while significant anisotropy in mechanical properties (216.7 MPa in X-Z plane and 121.0 MPa in X–Y plane) was observed for the ceramics with the addition of 1.5 wt TiO₂. The shrinkage and flexural strength of the ceramics decreased with the increase in CaCO₃ content due to the formation of elongated grains, which led to the formation of large-sized residual pores in the ceramics. The addition of MgO help decrease the anisotropic differences in shrinkage and flexural strength of the sintered ceramics due to the formation of regularly shaped grains. This work provides guidance on the adjustment in flexural strength, shrinkage, and anisotropic behavior of 3D printed alumina ceramics, and provides new methods for the fabrication of 3D printed alumina ceramics with superior mechanical properties.     

Improved 3D Printing and Cell Biology Characterization of Inorganic-Filler Containing Alginate-Based Composites for Bone Regeneration: Particle Shape and Effective Surface Area Are the Dominant Factors for Printing Performance

The use of organic–inorganic 3D printed composites with enhanced properties in biomedical applications continues to increase. The present study focuses on the development of 3D printed alginate-based composites incorporating inorganic fillers with different shapes (angular and round), for bone regeneration. Reactive fillers (bioactive glass 13–93 and hydroxyapatite) and non-reactive fillers (inert soda–lime glass) were investigated. Rheological studies and the characterization of various extrusion-based parameters, including material throughput, printability, shape fidelity and filament fusion, were carried out to identify the parameters dominating the printing process. It was shown that the effective surface area of the filler particle has the highest impact on the printing behavior, while the filler reactivity presents a side aspect. Composites with angular particle morphologies showed the same high resolution during the printing process, almost independent from their reactivity, while composites with comparable amounts of round filler particles lacked stackability after printing. Further, it could be shown that a higher effective surface area of the particles can circumvent the need for a higher filler content for obtaining convincing printing results. In addition, it was proven that, by changing the particle shape, the critical filler content for the obtained adequate printability can be altered. Preliminary in vitro biocompatibility investigations were carried out with the bioactive glass containing ink. The 3D printed ink, forming an interconnected porous scaffold, was analyzed regarding its biocompatibility in direct or indirect contact with the pre-osteoblast cell line MC3T3-E1. Both kinds of cell tests showed increased viability and a high rate of proliferation, with complete coverage of the 3D scaffolds’ surface already after 7 d post cell-seeding.     

DLP 3D printing porous β-tricalcium phosphate scaffold by the use of acrylate/ceramic composite slurry

Digital light processing (DLP) 3D printing has been utilized to fabricate controlled porous β-tricalcium phosphate (β-TCP) scaffolds, which promote cell adhesion and angiogenesis during bone regeneration. However, the current limitation of DLP 3D printing for the fabrication of β-TCP scaffold is how to prepare a low viscosity ceramic slurry and remove the toxicity of residual non-polymerized slurry. The present study has developed a low viscosity ceramic slurry system by mixing β-TCP with photosensitive acrylate resin, and the viscosity of slurry is about 3 Pa s and the solid content of β-TCP can be as high as 60 wt%. After optimizing the ratio of slurry, printing, degreasing and sintering processes, the maximum compressive strength of the DLP printed scaffolds reaches up to 9.89 MPa, while the porosity keeps ca. 40%. According to the proliferation of cells, it confirms the preserved biocompatibility of DLP-fabricated β-TCP scaffolds. These porous scaffolds made by DLP 3D printing technology is of great significance for bone regeneration, and will also help to expand the application of DLP technology in biomedical field.     

Highly Organized Porous Gelatin-Based Scaffold by Microfluidic 3D-Foaming Technology and Dynamic Culture for Cartilage Tissue Engineering

A gelatin-based hydrogel scaffold with highly uniform pore size and biocompatibility was fabricated for cartilage tissue engineering using microfluidic 3D-foaming technology. Mainly, bubbles with different diameters, such as 100 μm and 160 μm, were produced by introducing an optimized nitrogen gas and gelatin solution at an optimized flow rate, and N₂/gelatin bubbles were formed. Furthermore, a cross-linking agent (1-ethyl-3-(3-dimethyl aminopropyl)-carbodiimide, EDC) was employed for the cross-linking reaction of the gelatin-based hydrogel scaffold with uniform bubbles, and then the interface between the close cells were broken by degassing. The pore uniformity of the gelatin-based hydrogel scaffolds was confirmed by use of a bright field microscope, conjugate focus microscope and scanning electron microscope. The in vitro degradation rate, mechanical properties, and swelling rate of gelatin-based hydrogel scaffolds with highly uniform pore size were studied. Rabbit knee cartilage was cultured, and its extracellular matrix content was analyzed. Histological analysis and immunofluorescence staining were employed to confirm the activity of the rabbit knee chondrocytes. The chondrocytes were seeded into the resulting 3D porous gelatin-based hydrogel scaffolds. The growth conditions of the chondrocyte culture on the resulting 3D porous gelatin-based hydrogel scaffolds were evaluated by MTT analysis, live/dead cell activity analysis, and extracellular matrix content analysis. Additionally, a dynamic culture of cartilage tissue was performed, and the expression of cartilage-specific proteins within the culture time was studied by immunofluorescence staining analysis. The gelatin-based hydrogel scaffold encouraged chondrocyte proliferation, promoting the expression of collagen type II, aggrecan, and sox9 while retaining the structural stability and durability of the cartilage after dynamic compression and promoting cartilage repair.     

Enhanced in vitro inhibition of MCF-7 and magnetic properties of cobalt incorporated calcium phosphate (HAp and β-TCP) nanoparticles

The Co²⁺ (0.1 M) incorporated hydroxyapatite (HAp) and beta tricalcium phosphate (β-TCP) nanoparticles were synthesized by the microwave assisted technique and sintering of HAp respectively. The samples were thermally treated at temperatures ranging from 200 to 1000°C. The partial substitutions of Co²⁺ at the Ca²⁺ site of HAp were confirmed from the slight shift (～0.2°) in the (002) and (211) XRD peaks. The morphology of the nanoparticles was transformed from nanospheres to twinned particles on thermal treatment. In addition, the particle size of Co-600 was increased (from ～50 nm to ～100 nm) due to the recrystallization process. Further, the thermal treatment enhanced the crystallinity (41.15 to 90.16%), retentivity (M_r) and coercivity (H_c) of the nanoparticles. The cobalt incorporated HAp and β-TCP possessed paramagnetic property. The excellent bioactivity of β-TCP has been confirmed by the mineralization in simulated body fluid (SBF). Compared to HAp, β-TCP possessed better compatibility towards C2C12 cells on cobalt incorporation as evidenced by the in vitro cell viability. Moreover, both HAp and β-TCP have significantly inhibited the growth of MCF-7 on increasing the interaction time (72 h). Hence, the inhibition characteristics of Co²⁺ incorporated calcium phosphate (CaP) towards MCF-7 (without affecting the normal cells) demonstrate its competency as a potential material for cancer therapy over the already existing nanoparticles.