Bi-functionalization of glass surfaces with poly-L-lysine conjugated silica particles and polyethylene glycol for selective cellular attachment and proliferation

Fabrication of microstructured patterns serves as a powerful tool for studying the cellular responses toward synthetic materials at the material–cell interface for tissue engineering. Silica particles can effectively act as a substrate for cellular attachment and growth owing to its biocompatible nature and facile surface chemistry. In the current study, a non-lithographic microfabrication method for patterning of particles was devised using silica particles (~ 600 nm) and epoxy-silane-functionalized glass surfaces. Poly-L-lysine (PLL) was covalently attached to modified silica particles which were subsequently patterned onto the functionalized glass surfaces. PLL played a dual role. Firstly, it served as a bi-linker by covalently attaching modified particles on epoxy functionalized glass surfaces. Secondly, it facilitated cellular attachment on the pattern via electrostatic interactions. The vacant unpatterned regions were passivated with methoxy-polyethylene glycol-amino (MPA) to avoid non-specific cellular attachments. A549 cells were found to grow specifically on the monolayered silica patterns having lower packing density and exhibited stretched morphology, indicating cellular attachment to the substrate, whereas the MPA passivated areas were capable of blocking cell adhesion successfully. The highlight of the reported novel method lies in the dual use of PLL which not only provided necessary control over the surface chemistry by allowing fabrication of desired patterns but also facilitated selective cellular attachment on the generated patterns. Therefore, we report a simple process for micropatterning the cells on desired patterns via surface bi-functionalization for selective cellular attachment and proliferation.