Biodegradable chitosan nanogels crosslinked with genipin

► Chitosan was crosslinked with genipin in reverse microemulsion medium. ► Chitosan-genipin crosslinking reaction was quantitatively evaluated by UV-vis and 1H NMR. ► Chitosan-genipin nanogels showed improved water solubility at neutral pHs. ► Swelling behaviour of the nanogels was studied as function of crosslinking degree and pH.