Pectins, complex plant-derived polysaccharides, are novel candidates for biomaterial nanocoatings. Pectic rhamnogalacturonan-I regions (RG-I) can be enzymatically treated to so-called modified hairy regions (MHR). We surveyed the growth and differentiation of murine preosteoblastic MC3T3-E1 cells on Petri dishes coated with RG-Is from native or genetically engineered potato tubers. Uncoated tissue culture polystyrene (TCPS) and aminated (AMI) dishes served as controls. MHRPTR_GAL sample was depleted of galactose (9 mol % galactose; 23 mol % arabinose) and MHRPTR_ARA of arabinose (61 mol % galactose; 6 mol % arabinose). Wild-type (modified hairy region from potato pectin (MHRP)_WT) fragment contained default amounts (58 mol % galactose; 13 mol % arabinose) of both sugars. Focal adhesions (FAs) indicating cellular attachment were quantified. Reverse transcriptase polymerase chain reaction (RT-PCR) of alkaline phosphatase and osteocalcin genes indicating osteoblastic differentiation was performed along with staining the produced calcium with tetracycline as an indicator of osteoblastic differentiation. Osteoblasts proliferated on all the samples to some extent. The control surfaces performed better than any of the pectin samples, of which the MHRP_WT seemed to function best. FA length was greater on MHRPTR_GAL than on other pectin samples, otherwise the mutants did not significantly deviate. RT-PCR results indicate that differences between the samples at the gene expression level might be even subtler. However, tetracycline-stained calcium-containing mineral was detected merely only on uncoated TCPS. These results indicate the possibility to affect bone cell growth with in vivo-modified pectin fragments, consecutively providing information on the significance of certain monosaccharides on the biocompatibility of these polysaccharides. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2012.