ABSTRACT
Despite recent advances in the development of scaffold-based three-dimensional (3D) cell models, challenges persist in imaging and monitoring cell behavior within these complex structures due to their heterogeneous cell distribution and geometries. Incorporating sensors into 3D scaffolds provides a potential solution for real-time, in situ sensing and imaging of biological processes such as cell growth and disease development. We introduce a 3D printed hydrogel-based scaffold capable of supporting both surface-enhanced Raman scattering (SERS) biosensing and imaging of 3D breast cancer cell models. The scaffold incorporates plasmonic nanoparticles and SERS tags, for sensing and imaging, respectively. We demonstrate the scaffold's adaptability and modularity in supporting breast cancer spheroids, thereby enabling spatial and temporal monitoring of tumor evolution.
Subject(s)
Spectrum Analysis, Raman , Humans , Spectrum Analysis, Raman/methods , Breast Neoplasms/pathology , Breast Neoplasms/diagnostic imaging , Hydrogels/chemistry , Surface Properties , Cell Line, Tumor , Biosensing Techniques/methods , Tissue Scaffolds/chemistry , Metal Nanoparticles/chemistry , Spheroids, Cellular/pathologyABSTRACT
With the ever-increasing use of 3D cell models toward studying bio-nano interactions and offering alternatives to traditional 2D in vitro and in vivo experiments, methods to image biological tissue in real time and with high spatial resolution have become a must. A suitable technique therefore is surface-enhanced Raman scattering (SERS)-based microscopy, which additionally features reduced photocytotoxicity and improved light penetration. However, optimization of imaging and postprocessing parameters is still required. Herein we present a method to monitor cell proliferation over time in 3D, using multifunctional 3D-printed scaffolds composed of biologically inert poly(lactic-co-glycolic acid) (PLGA) as the base material, in which fluorescent labels and SERS-active gold nanoparticles (AuNPs) can be embedded. The combination of imaging techniques allows optimization of SERS imaging parameters for cell monitoring. The scaffolds provide anchoring points for cell adhesion, so that cell growth can be observed in a suspended 3D matrix, with multiple reference points for confocal fluorescence and SERS imaging. By prelabeling cells with SERS-encoded AuNPs and fluorophores, cell proliferation and migration can be simultaneously monitored through confocal Raman and fluorescence microscopy. These scaffolds provide a simple method to follow cell dynamics in 4D, with minimal disturbance to the tissue model.
