Background: Naturally derived polymeric substances have recently gained much attention in tissue engineering applications due to their unique biological activities. The present work deals with fucoidan's isolation, characterizations, and osteogenic differentiation. The fucoidan has been used for several biological and biomedical applications. The research on fucoidan concerning its application mainly in osteogenic differentiation is scanty. Thus, the study examines the osteogenic differentiation property of purified fucoidan from Sargassum ilicifolium. Methods: The isolation of fucoidan was performed by using probe-sonication combined with microwave extraction and hot water extraction methods. The probe sonication-microwave procedure provides a 1.5X higher yield than the hot water extraction method. The probe sonication-microwave derived crude fucoidan was further purified with DEAE-Cellulose anion-exchange chromatography. The structural characterization of purified fucoidan was carried out by UV-Visible spectroscopy, X-Ray diffraction, Fourier transform infrared spectroscopy, Thermogravimetric analysis, and (NMR)-N-1H analysis. In addition, the osteogenic differentiation ability was studied by performing cell proliferation, alkaline phosphatase activity, mineralization, and expression of osteoblast markers with murine mesenchymal stem cells (C3H10T1/2). Significant findings: The findings of the structural study confirm the presence of sulfates and hydroxyl groups in the isolated fucoidan. The (NMR)-N-1H results confirm the occurrence of fucose residues. The in vitro study results demonstrate that the purified fucoidan significantly scavenges the formation of free radicles and induces the alkaline phosphatase activity, mineralization, and the expression of osteoblast-specific genes. The findings indicate that the fucoidan from Sargassum ilicifolium can be a potential biomaterial for bone regeneration.

About 2.2 million bone graft operations are performed per year worldwide to treat bone defects caused by motor defects, congenital disabilities, bone tumors, and other causes. Autografts, allografts, and synthetic grafts are widely used for bone graft substitutes. Even though autograft is the gold standard for treating bone defects, there is a problem with insufficient donor sites and secondary surgical procedures. Therefore, synthetic graft construction has received a lot of attention to mimicking the autograft technique. With the development of artificial synthetic bone graft replacement, biopolymers in combination with bioceramics play an essential role in the construction of bone tissue. In this article, we have discussed the role of polymeric substances, polyglycolic acid, polylactic acid, poly (caprolactone), poly (lactic-co-glycolic acid), chitosan, alginate, cellulose, dextran, hyaluronic acid, pectin, starch, carrageenan, and fucoidan, for bone tissue engineering applications. These polymers in the composite biomaterials have better mechanical properties, improved porosity, enhanced cellular function in gene expression, and biomineral formations for bone tissue engineering applications.

Globally, millions of bone graft procedures are being performed by clinicians annually to treat the rising prevalence of bone defects. Here, the study designed a fucoidan from Sargassum ilicifolium incorporated in an osteo-inductive scaffold comprising calcium crosslinked sodium alginate-nano hydroxyapatite-nano graphene oxide (Alg-HA-GO-F), which tends to serve as a bone graft substitute. The physiochemical characterization that includes FT-IR, XRD, and TGA confirms the structural integration between the materials. The SEM and AFM reveal highly suitable surface properties, such as porosity and nanoscale roughness. The incorporation of GO enhanced the mechanical strength of the Alg-HA-GO-F. The findings demonstrate the slower degradation and improved protein adsorption in the fucoidan-loaded scaffolds. The slow and sustained release of fucoidan in PBS for 120 h provides the developed system with an added advantage. The apatite formation ability of Alg-HA-GO-F in the SBF solution predicts the scaffold’s osteointegration and bone-bonding capability. In vitro studies using C3H10T1/2 revealed a 1.5X times greater cell proliferation in the fucoidan-loaded scaffold than in the control. Further, the results determined the augmented alkaline phosphatase and mineralization activity. The physical, structural, and enriching osteogenic potential results of Alg-HA-GO-F indicate that it can be a potential bone graft substitute for orthopedic applications.

Dental caries is a common problem in adolescents, leading to permanent loss of teeth or cavitation. Caries is a continuous process wherein demineralization and remineralization occur regularly. Hydroxyapatite (HA) is one of the most biocompatible and bioactive materials, as it closely resembles the mineral composition of teeth. The present study deals with isolating hydroxyapatite from fish bone (Epinephelus chlorostigma) by alkaline hydrolysis and thermal calcination. The isolated nano HA was characterized using FT-IR, XRD, TGA, FE-SEM-EDX, and HR-TEM analysis. The nano HA isolated by alkaline hydrolysis is nontoxic, and the cells are viable. The isolated HA enhances the proliferation of L929 cells. The remineralization potential of the extracted nano HA was evaluated in healthy premolars by DIAGNOdent/laser fluorescence quantification, surface microhardness test, and SEM-EDX analysis. Surface morphological observations in SEM and EDX analyses show that thermally calcined HA and alkali-treated HA can induce mineralization and deposit minerals. Therefore, HA obtained from Epinephelus chlorostigma could be a potential biomaterial for treating early caries.

Hydrocolloids are natural polymeric substances which are commonly isolated from marine macroalgae. From the last four decades, hydrocolloids have played a significant role in food, cosmeceuticals, nutraceuticals, and pharmaceutical applications due to their excellent properties as thickeners, for hydrogel formation, for moisture retention, etc. As concern with the global food demand grows, these hydrocolloids play a vital role in the next generation food industries to meet global food consumption. Major hydrocolloids from the marine macroalgae are alginate, agar, carrageenan, etc. In this chapter, we discuss the isolation procedure, common sources, chemical composition, and structural and physio-chemical properties of hydrocolloids derived from marine macroalgae. Different kinds of isolation techniques and applications are also discussed. In conclusion, the proper isolation techniques and appropriate utilization of these hydrocolloids will be promising in food-related applications.

Over 2.2 million bone graft transplantations are performed by clinicians worldwide annually. The development of synthetic bone graft substitute for the treatment of bone defects is still an utmost challenge in bone tissue engineering. In the current study, we have fabricated calcium ion cross-linked alginate (Alg), alginate-graphene oxide (Alg-GO) and alginate-graphene oxide-dexamethasone (Alg-GO-Dex) composite microspheres as an alternative bone graft substitute. Various properties of developed microspheres were investigated using appropriate characterization tools including Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy combined with energy dispersive X-ray diffraction. In vitro biomineralization study was performed using simulated body fluid (SBF) solution. Biocompatibility of the developed microspheres was studied with osteoblast-like cells (MG-63). The developed microspheres showed more than 80% of porosity and dispersion of GO in the alginate matrix was uniform. The size of developed microspheres is in the range of 1.5 +/- 0.5 mm, and Dex drug was released from the microspheres in sustainable manner. Excellent apatite formation was observed on the surface of the microspheres using SBF solution which is useful for bone tissue regeneration. In vitro studies using osteoblast like MG-63 cells revealed profound biocompatibility. Thus, the developed AlgGO-Dex composite microspheres have potential applications in drug delivery system towards bone tissue engineering applications.