The emerging field of biomedical and tissue engineering requires novel surface fabrication approaches to impart advancements for a range of applications <i>viz.</i> medical implants, cell culture tools, regenerative medicines etc. Variation in the topographical features along with different chemistries has always been a popularly explored strategy to get control over mammalian cell responses. This research work investigates the generation of potential biomaterial surface coatings fabricated with binary colloidal crystal (BCC) layers containing large (L) micro- and small (s) colloidal nano-spheres, thereby giving rise to 2D or 3D surface micro-/nanotopographies. We apply a covalent binding approach to conjugate different chemical entities such as non-fouling polymers (e.g. PEG) or integrin binding RGD peptide, being involved in promoting cellular attachment, to large silica (Si) particles. Afterwards, we utilize a variety of pre-modified Si and smaller sized polymeric particles in different aspect ratios, chemical compositions and varied colloidal layer numbers to generate well-ordered BCC topographical features. A range of physico-chemical characterization techniques including zeta potential, x-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and atomic force microscopy (AFM) were employed to optimize these tunable cell-culture substrates. Four different well-defined BCC combinations presenting cues for controlled bio-interfacial interactions via PEG and RGD were chosen to perform cellular behavioural studies. We used epifluorescence microscopy and found that well controlled surface chemistry of the BCC layers can induce significant impact on the adhesion, proliferation and spreading behaviour of MG63 osteoblasts in conjunction with distinguishable cellular morphology changes. Thus, PEG grafted BCCs can be useful where cell adhesion is needed in a limited and controllable manner (for instance cell spheroids for use in drug screening of controlled differentation in 3D microenvironments) while RGD grafted BCCs are able to exhibit significantly higher cell count, greater spreading area and induced lineage-specific gene expression.

Polyethylene glycol and RGD immobilized binary colloidal crystal nanostructures as tunable substrates for cell culture

2019 Spring National Meeting

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