Tissue engineering research has been primarily focused on the development of customizable 3D scaffolds capable of promoting natural tissue regeneration while providing robust structural support. Synthetic polymer-based composites have garnered significant attention in recent years for biocompatibility and biodegradability, particularly in hard tissue engineering. In this study, we have chosen to combine the synthetic polymer PLA with natural silica as Diatomaceous earth for creating a customizable biomaterial tailored for bone tissue engineering applications. To create the PLA-Diatom composites, we employed melt mixing and hot-press methods, using two different types of diatoms: calcinated and raw diatoms. To enhance the compatibility of PLA, PEG and PEG/POSS were introduced as plasticizers/compatibilizers. Various concentrations of these plasticizers and reinforcing agents were meticulously applied to the PLA matrix to fine-tune the properties of the PLA biomaterial. Our comprehensive characterization involved SEM for morphology, mechanical testing, rheological analysis, AFM for roughness, contact angle analysis for surface wettability, swelling property, and FTIR for chemical structure. Our findings revealed that 3% diatom addition into PLA significantly improved tensile strength (32,72±0,27 for PLA and 51,51±4,15 for calcinated to 55,33±0,97 MPa for raw diatom), slight decrease in modulus (2277±45,65 for PLA to 2183,11 MPa for calcinated and 2246,43±24,19 for raw diatom), and reduced strain with higher diatom concentrations. Rheological analysis indicated a shift towards more liquid-like behaviour in PLA-Diatom composites, further enhanced by plasticizers, ensuring stable viscosities. Surface roughness increased with pure and plasticized PLA with diatom application. Surface wettability and water uptake capacity improved significantly compared to pure PLA.