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Apatite layers formed by simulated body fluid (SBF) on the surface of calcium-based scaffolds have been proven to enhance the osteoblastic activity of pre-osteoblasts and osteogenic activity of bone marrow-derived stem cell (BM-SCs). Previously developed Alginate/Cockle shell powder nanobiocomposite bone scaffold (Alg/nCP) has been shown to possess excellent osteoconductive properties. The effect of pre-mineralization of the scaffold surface towards the growth and differentiation of BM-SCs’ were evaluated using microscopic and biochemical methods in scaffolds divided into SBF pre-treated and control groups at two time points. MTT proliferation assay showed statistically significant decrease in cell proliferation in SBF group for both culture periods. SEM observation revealed growth of BM-SCs and scaffold surface mineralisation and calcium deposition in both groups with higher intensity observable in the control group. Supporting biochemical studies showed a significant decrease in alkaline phosphatase (ALP) level indicating a lesser osteogenic differentiation in the SBF group as compared to control. Pre-mineralisation of scaffolds in SBF produced a contradicting result in which it did not provide a better environment for growth and proliferation of BM-SCs. However, the Alg/nCP scaffold did show potentials in supporting the osteogenic differentiation of the stem cells.

Cockle shells contribute to a large amount of waste product in South East Asia due to the extensive culturing of the mollusc for consumption. These nacreous materials in the recent years have been gaining wider popularity due to its potential use as biomaterials. As shown in various studies, cockle shell powder consists of 95-98% aragonite form of calcium carbonate (CaCO3). The calcium carbonate obtained from cockle shells are easily converted into nanoparticles, which have shown encouraging results in bone tissue grafting. With the recent advancement in bone tissue engineering and development of a newer generation of biomaterial based bone scaffolds, the cockle shell powder has promising applications in the near future to be used in the formulation of bone grafting materials. In this review, the use of biomaterials in bone tissue grafting and nacreous materials as potential biomaterials with a focus on the cockle shell and its recent advancement as the main component in the formulation of a nanobiocomposite bone scaffold is discussed.

The present study investigates the involvement of the l-arginine-Nitric Oxide-cGMP-K⁺ ATP pathways responsible for the action of anti-allodynic and antihyperalgesic activities of zerumbone in chronic constriction injury (CCI) induced neuropathic pain in mice. The role of l-arginine-NO-cGMP-K⁺ was assessed by the von Frey and the Randall-Selitto tests. Both allodynia and hyperalgesia assessments were carried out on the 14th day post CCI, 30 min after treatments were given for each respective pathway. Anti-allodynic and antihyperalgesic effects of zerumbone (10 mg/kg, i.p) were significantly reversed by the pre-treatment of l-arginine (10 mg/kg), 1H [1,2,4]Oxadiazole[4,3a]quinoxalin-1-one (ODQ), a soluble guanosyl cyclase blocker (2 mg/kg i.p.) and glibenclamide (ATP-sensitive potassium channel blocker) (10 mg/kg i.p.) (p < 0.05). Taken together, these results indicate that systemic administration of zerumbone produces significant anti-allodynic and antihyperalgesic activities in neuropathic pain in mice possibly due to involvement of the l-arginine-NO-cGMP-PKG-K⁺ ATP channel pathways in CCI model.

Neuropathic pain arises from the injury of nervous system. The condition is extremely difficult to be treated due to the ineffectiveness and presence of various adverse effects of the currently available drugs. In the present study, we investigated the antiallodynic and antihyperlagesic properties of cardamonin, a naturally occurring chalcone in chronic constriction injury (CCI)-induced neuropathic pain mice model. Our findings showed that single and repeated dose of intra-peritoneal administration of cardamonin (3, 10, 30 mg/kg) significantly inhibited (P<0.001) the chronic constriction injury-induced neuropathic pain using the Hargreaves plantar test, Randall-Selitto analgesiometer test, dynamic plantar anesthesiometer test and the cold plate test in comparison with the positive control drug used (amitriptyline hydrochloride, 20 mg/kg, i.p.). Pre-treatment with naloxone hydrochloride (1 mg/kg, i.p.) and naloxone methiodide (1 mg/kg, s.c) significantly reversed the antiallodynic and antihyperalgesic effects of cardamonin in dynamic plantar anesthesiometer test and Hargreaves plantar test, respectively. In conclusion, the current findings demonstrated novel antiallodynic and antihyperalgesic effects of cardamonin through the activation of the opioidergic system both peripherally and centrally and may prove to be a potent lead compound for the development of neuropathic pain drugs in the future.

A novel porous three-dimensional bone scaffold was developed using a natural polymer (alginate/Alg) in combination with a naturally obtained biomineral (nano cockle shell powder/nCP) through lyophilization techniques. The scaffold was developed in varying composition mixture of Alg-nCP and characterized using various evaluation techniques as well as preliminary in vitro studies on MG63 human osteoblast cells. Morphological observations using SEM revealed variations in structures with the use of different Alg-nCP composition ratios. All the developed scaffolds showed a porous structure with pore sizes ideal for facilitating new bone growth; however, not all combination mixtures showed subsequent favorable characteristics to be used for biological applications. Scaffolds produced using the combination mixture of 40% Alg and 60% nCP produced significantly promising results in terms of mechanical strength, degradation rate, and increased cell proliferation rates making it potentially the optimum composition mixture of Alg-nCP with future application prospects.

Shells are comparable to bones of vertebrates due to the similarities in mechanical properties and strength. The cockle shell material may act as an anolog of calcium carbonate in an in vivo condition that makes it a potential bone grafting material. The present study involves the development and evaluation of a novel three-dimensional alginate/nano cockle shell powder biocomposite bone scaffold prepared through lyophilization and divalent cation cross-linking methods. Element analysis revealed that the shell material consisted of 96% of calcium carbonate with no traces of toxic elements while physiochemical analysis revealed a predominantly aragonite form of calcium carbonate polymorph. The cockle shell powder was converted to nano particles using a biomineralization catalyst through a simple chemical method and was used as a representative of the inorganic phase while sodium alginic acid (alginate) was used as the organic phase in the development of the nano-biocomposite scaffold. The scaffold mixture was prepared in varying composition ratios, characterized and evaluated through various characterization studies. Scanning electron microscopy (SEM) analysis revealed the micro architecture of the scaffolds with pore size ranging from 10 – 336 μm diameters. The porosity of the scaffolds was found to be above 60%. Mechanical properties of the tested scaffolds showed the composition ratio of 40% alginate and 60% nano cockle powder (Alg:nCP=40:60) possesed favorable mechanical properties ranging between the spongy bone structures compressive strength. Swelling ratio of the scaffolds showed an average of 30% medium uptake ability with 20 – 30% changes in diameter. Enzymatic degradation test revealed an increase in structural stability proportional to the amount of nano cockle shell powder within the composition while pH changes observed during degradation studies revealed a neutralizing effect of nano cockle shell powder towards the potential acidification of the solutio