The finding suggested that the nanoposts density might be capable of directly regulating cytoskeletal stiffness and the dynamic changes in stiffness correlated with the differentiation of hMSC into osteogenic or adipogenic lineages. Using spatially ordered and disordered arrays of nanopatterned c-RGDfK peptide with well-defined interpattern distances that ranged from 55 to 100 nm against a non-adhesive background, Huang et al. further characterized the influence of nanospacing on adhesion and spreading.24 When osteoblasts were cultured on nano-engineered substrates, it was found that a critical lateral inter-distance of 70 nm was required for effective clustering of integrins, beyond which (>70 nm) the cells were unable to spread effectively. It was proposed that an inability to cross-link the integrins at the cytoplasmic end by proteins such as talin and α-actin to a comparable size (60 nm) might be the reason for this limitation.