Warayuth SajomsangPattarapond GonilUracha Rungsardthong RuktanonchaiMaleenart PetchsangsaiPraneet OpanasopitSatit PuttipipatkhachornThailand National Science and Technology Development AgencySilpakorn UniversityMahidol University2018-11-092018-11-092014-04-15Carbohydrate Polymers. Vol.104, No.1 (2014), 17-22014486172-s2.0-84893202558https://repository.li.mahidol.ac.th/handle/20.500.14594/33623Methylated N-pyridylmethyl chitosan chlorides (M-PyMeChCs) with a similar total degree of quaternization (DQT) and molecular weight but different N-pyridinium positions were synthesized by reductive amination and methylation, respectively. The effect of N-pyridinium positions on transfection efficiency and cytotoxicity was investigated in human hepatoma (Huh7) cell lines. The results revealed that M-PyMeChCs are able to form a complete complex formation with DNA since there is an N/P ratio of 5. The particle sizes of M-PyMeChCs/DNA nanopolyplexes were approximately 300 nm and indicated a positive charge. The morphology of these nanopolyplexes was found to be in a spherical shape which was investigated by using the transmission electron microscopy (TEM). The M4-PyMeChC/DNA nanopolyplexes showed highest in vitro transfection efficiency in Huh7 cells at N/P ratio of 20 compared to M2-PyMeChC/DNA and M3-PyMeChC/DNA nanopolyplexes. In comparison to M3-PyMeChC/DNA nanopolyplexes, M2-PyMeChC/DNA and M4-PyMeChC/DNA nanopolyplexes showed lower cytotoxicity in Huh7 cells. Our result demonstrated that N-pyridinium positions of M-PyMeChCs are related to transfection efficiency and cytotoxicity. © 2014 Elsevier Ltd.Mahidol UniversityChemistryMaterials ScienceMedicineArticleSCOPUS10.1016/j.carbpol.2013.12.077