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 (CaCO 3). 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.

Biocompatibility and growth of osteoblast on bone scaffolds play an important role towards their therapeutic application.

Improvement in bone tissue engineered scaffolds plays an important role in determining the healing outcome. This study aims to investigate the functional performance of previously developed nanobiocomposite bone scaffolds using bone morphogenetic protein-2 (BMP-2) for comparative analysis. The structural morphology and porosity of the scaffolds were analysed using scanning electron microscopy prior to dividing them into two groups, BMP-2 treated and control, for the surface mineralization study, in vitro and in vivo evaluation. The surface mineralization study showed the presence of plate-like calcium and phosphorus apatite crystallites in both groups indicative of the mineralization process. Osteoblasts (MC3T3-E1 subclone 4) cultured on the scaffold showed changes in the surface morphology with the presence of mineralization elements and the extensive presence of collagen fibres in BMP-2 scaffolds compared to the control. This was supported by a significant increase in calcium and alkaline phosphatase (ALP) activity showing enhancement in osteoconductiveness. In vivo studies conducted on 20 male ICR albino mice through subcutaneous dorsum implantation of scaffolds for 2 and 4 weeks showed a significant increase in the histological score for inflammatory cells, scaffold degradation and neovascularization at week 4 compared to week 2 for the BMP-2 scaffold. These findings are supported by a significant decrease in ALP activity indicative of scaffold mineralization. There were no significant differences between BMP-2 and control scaffolds within the period of this study. In conclusion, the functional performance of the scaffolds was mildly accelerated in BMP-2 compared to the control scaffold which showed promising properties in supporting osteogenesis without the use of any promoting factors.

Kalsium karbonat (CaCO 3) memainkan peranan yang penting dalam merangsang pertumbuhan osteoblas. Kajian ini dijalankan untuk membandingkan prestasi perancah nanobiokomposit alginat/kulit kerang (nCP) yang mengandungi CaCO 3 dari sumber semula jadi dan perancah alginat/kalsium karbonat (CC) yang mengandungi CaCO 3 sintetik terhadap pertumbuhan osteoblas melalui kajian in vitro dan pemerhatian awal kebioserasian in vivo. Perancah tulang berbentuk tiga dimensi dibangunkan dengan menggunakan campuran 40% Alginat dan 60% serbuk kulit kerang bersaiz nano (perancah nCP) atau serbuk CaCO 3 sintetik (perancah CC). Kajian in vitro terhadap pembebasan kalsium dan aktiviti enzim alkalin fosfatase (ALP) pada kedua-dua perancah yang telah dibenihkan dengan osteoblas ditentukan pada hari ketiga, kelima dan ketujuh pengkulturan. Kajian in vivo dijalankan dengan implantasi subkutan perancah yang telah dibenihkan dengan osteoblas pada bahagian dorsum lapan ekor mencit selama 21 hari. Setelah 21 hari, perancah dikeluarkan dari mencit untuk pemerhatian histologi menggunakan pewarnaan H&E and von Kossa. Hasil kajian in vitro menunjukkan peningkatan secara signifikan (p < 0.05) perembesan kalsium dan aktiviti enzim ALP pada perancah nCP pada hari ketujuh berbanding perancah CC pada hari ketiga dan kelima. Pemerhatian histologi terhadap kedua-dua perancah menunjukkan infiltrasi dan proliferasi osteoblas serta pembentukan tisu tulang peringkat awal. Pembentukan saluran darah juga dapat dikenal pasti pada perancah nCP. Kedua-dua perancah menunjukkan potensi untuk menyokong dan membantu pertumbuhan osteoblas namun perancah nCP didapati menunjukkan potensi yang lebih baik secara keseluruhan. Kesimpulannya, CaCO 3 dari sumber semula jadi iaitu kulit kerang dan bersaiz nano berpotensi untuk dijadikan sebagai biobahan di dalam aplikasi kejuruteraan tisu tulang.

Establishing experimental models to study neuropathic pain has been challenging due to the complex mechanism underlying the condition. Although in vivo models have been useful in the observation of behavioural pain responses, it should be acknowledged that species-to-species variance can lead to differences in terms of molecular mechanism and genetic expression. The study of molecular and signal transduction of neuropathic pain using in vivo models faces limitations due to ethical considerations involving pain induction in animals and the intricacy of molecular interactions in the pathophysiology of the condition. Hence, developing relevant in vitro models to study neuropathic pain is important, as it considers the physiological microenvironment and reduces the use of experimental animals. Several considerations should be taken into account in developing an in vitro model of neuropathic pain, including the use of either primary culture of cell lines with considerations to their origins; human or animal, the method of neuropathic pain-like induction and the relevant assays to assess pain. This review recapitulates previous research employing in vitro models in investigating the molecular mechanism of neuropathic pain, intending to provide an alternative to the growing concerns on in vivo neuropathic pain models.