Evaluasi Pengaruh Suhu Sintering terhadap Karakteristik Gugus Fungsional Hidroksipatit dari Cangkang Kerang Bambu (Solen Spp.) untuk Regenerasi Tulang

Abstract

Introduction: Hydroxyapatite (HAp) is a calcium phosphate–based bioceramic with high biocompatibility and a chemical structure similar to human bone minerals, making it highly promising for bone tissue engineering applications. One of the environmentally friendly and cost-effective natural sources of HAp is the bamboo clam shell (Solen spp.), which contains approximately 92–97% calcium carbonate (CaCO₃). However, synthesized hydroxyapatite generally still exhibits low crystallinity and an imperfect crystal structure. Therefore, the sintering process is carried out to improve the crystal structural order and stability of hydroxyapatite. Methods: This laboratory experimental study utilized the hydrothermal method by reacting calcium carbonate (CaCO₃) derived razor clam with ammonium dihydrogen phosphate ((NH₄)H₂PO₄) in a hydrothermal autoclave at a 1:6 molar ratio, heated at 180°C for 16 hours. The obtained hydroxyapatite was then sintered using a furnace at 800°C, 1000°C, and 1100°C for one hour before being analyzed using Fourier Transform Infrared Spectroscopy (FTIR) within the wavelength range of 500–4500 cm⁻¹ to identify functional groups. Results: The FTIR analysis results showed that all samples contained the characteristic functional groups of hydroxyapatite, namely –OH, CO₃²⁻, and PO₄³⁻. In the sample before sintering, the absorption bands appeared broad with relatively moderate intensity, indicating that the structure was still amorphous or less ordered. At 800°C, HAp remained in a semi-amorphous phase, as indicated by the still broad absorption bands, although an increase in structural order had begun to occur. Increasing the sintering temperature to 1000°C resulted in hydroxyapatite with higher crystallinity, as evidenced by sharper absorption bands, reflecting improved crystal structural order. At 1100°C, the absorption bands remained sharp and became narrower, indicating a more stable crystal structure, and no formation of secondary phases such as tricalcium phosphate (TCP) was observed. Consclusion: Sintering temperature influences the functional group characteristics of hydroxyapatite synthesized from bamboo clam shells (Solen spp.). Increasing the sintering temperature causes changes in the FTIR absorption bands, from broad to sharper peaks, indicating an improvement in the structural order and crystallinity of hydroxyapatite. All samples exhibit the characteristic functional groups of hydroxyapatite, namely – OH, CO₃²⁻, and PO₄³⁻, and no indication of secondary phase formation such as tricalcium phosphate (TCP) was observed. These findings demonstrate that bamboo clam shells (Solen spp.) have potential as a source of hydroxyapatite for biomaterial applications.