3D cell culture is an increasingly reliable method to mimic the in vivo environment in vitro and offers a robust platform for several investigations ranging from disease modelling, regenerative medicine to drug discovery and development. In addition, having more physiologically relevant 3D models of both healthy and diseased tissues will allow the better understanding of the key cellular processes and a more reliably development of safer and more effective therapies.
Advancement in preclinical in vitro 3D models such as spheroids and organoids has made use of biomaterials to mimic the complex in vivo environment; however, some widely used biomaterials have limitations as they are animal derived and lack of tuneability to faithfully mimic the in vivo counterpart. Recent advances in the use of tuneable synthetic peptide hydrogels, such as PeptiGels®, have shown potential to overcome these limitations by better simulating tissue microenvironments for enhanced research, allowing the generation of more physiologically and clinically relevant data.
Tuneable PeptiGels® were optimised (matrix stiffness and functionality) for the growth and culture of mesenchymal stem cells, pancreatic (Suit-2) and breast cancer cells (MCF-7, MDA-MB-231). The cultured cells were characterised by analysing their viability (live/dead assay), integrity and homogeneity using imaging techniques (brightfield and immunofluorescence). Mesenchymal stem cells cultured in PeptiGels® were differentiated towards osteogenic lineages. The differentiated cells were phenotyped (Immunocytochemistry and confocal imaging) for key bone markers (collagen-I, osteocalcin, alkaline phosphatase). Pancreatic and breast cancer cells cultured in PeptiGels® were examined for key tumour features (hypoxia and invasion) and drug penetration and efficacy.
Findings here demonstrated the use of tuneable PeptiGels® for the growth of cells to develop complex models such as organoids, tumour models, and their applications more broadly within regenerative medicine and drug discovery. PeptiGels® provided a 3-dimensional platform to support the growth and differentiation of mesenchymal stem cells into osteoblasts. The differentiated cells remain viable, proliferated throughout the duration of culture and displayed key functional capabilities by the deposition of key proteins (Col-1), osteocalcin, and alkaline phosphatase in addition to the presence of mineralization within the hydrogel, indicating that PeptiGels® can support the differentiation of stem cells into lineages of interest and has potential for tissue regeneration in different disease contexts.
The use of PeptiGels® also generated physiologically relevant in vitro 3D breast and pancreatic cancer models to replicate healthy and diseased human tissues. PeptiGels® were fine-tuned to recapitulate the tumour microenvironment and study cancer-specific biology such as pH modulation, hypoxia and changes in the mechanical properties involved in cancer cell activation and survival. PeptiGel®-based breast cancer 3D models allowed drug penetration and were resistant to Taximofen treatment when compared to scaffold-free 2D models, potentially offering a suitable physiologically relevant model for advanced drug discovery and development.
In conclusion, these tuneable peptide hydrogels - PeptiGels® are non-toxic, biocompatible, biodegradable and are tuneable to simulate different tissue microenvironments to provide physiologically and clinically relevant data.