## 3 Discussion
However, the growth was less efficient compared to tissue culture plastic. Cells on GPP exhibited notably higher proliferation and metabolic activity than those on VSCM, especially in the first week. This outcome is in line with the recent study showing that PDL stem cells achieved high proliferation rates on hybrid PCL/GE materials [28]. It is mentionable that the nanoscale surface structure of GE-blended scaffolds could significantly enhance the proliferation of PDL stem cells [29]. Cell proliferation/viability and metabolic activity results correspond with the findings of microscopy experiments, showing a higher cell density on GPP compared to VSCM. Periodontium is a complex heterogeneous structure consisting of a combination of hard and soft tissues. An effective periodontal regeneration requires the regeneration of all types of tissues, which makes fabricating the appropriate scaffold quite challenging. Therefore, we have investigated the effect of two scaffolds on the gene expression of various factors associated with the formation of different periodontal tissues. Periostin is specifically present in the periodontal ligament, where it fulfills a variety of functions in tissue development and periodontal disease [30]. We found that GPP had a more favorable effect on periostin expression in hPDL-MSCs than cells on VSCM after 7 days of culture, which implies that GPP has a stronger influence in prompting the hPDL-MSCs to differentiate into periodontal ligament cell populations. This finding agrees with recent research demonstrating that the trilayered bioscaffold produced from hybrid PCL and GE increased the expression of POSTN in PDL stem cells after 14 days of culture [28]. In addition to the ligament region, restoration and reconstruction of the cement tissue are essential for ensuring the integrity of attachment structures. The innate capacity of cementum repair is limited, and when the structures are absent and replaced by fibrous or bone tissue, root resorption or ankylosis is likely to occur [31]. CAP facilitates the attachment of collagen to the root surface and influences the migration and adherence of surrounding ligament fibroblasts [32,33]. CEMP1 is known to induce the differentiation of multiple cell types into cementoblast-like phenotypes and promote the formation of new cementum [34]. In this study, both biomaterials effectively promoted the expression of CEMP1 and CAP, from the early stage of culture, suggesting that they have the potential to support cementoblasts-like cell differentiation and cementogenesis. The earlier study has also shown that electrospun scaffolds combining GE and PCL enhance the expression levels of these proteins in PDL stem cells by day 7 [28]. The alveolar bone, being the principal supportive tissue of the periodontal complex, is regarded as the indispensable basis for both the functional and structural aspects of periodontal regeneration. Osteocalcin, as a key factor in the late stage of osteogenesis, is closely linked to the mineralization of bone tissue and the homeostasis of calcium ions [35]. [PERSON] et al. found that hMSCs grown on PCL/GE electrospun scaffold revealed increased OCN expression after 1 week [36]. We did not detect the OCN expression within the first week, which can be because hPDL-MSCs are progenitor undifferentiated cells. Moreover, a previous study showed that CEMP1 might downregulated OCN expression in PDL cells [31]. However, by day 14, both biomaterials seemed to have a positive regulatory effect on OCN expression, with VSCM showing a more noticeable impact. This observation might imply that at this point, hPDL-MSCs start to differentiate into bone cells, with VSCM showing a more noticeable impact than GPP. Collagen 1 is the primary organic component of ligaments, bone, and cementum; the proportion of COL1 in periodontal ligament even determines the health and functionality of the ligament's structure [37, 31].