Fig. 6: Safety assessment of MNs. | Nature Communications

Fig. 6: Safety assessment of MNs.

From: Catechol-based chemistry for hypoglycemia-responsive delivery of zinc-glucagon via hydrogel-based microneedle patch technology

Fig. 6

A In vitro, cytotoxicity study of the MN, MN containing Z-GCN and released Z-GCN in HaCaT keratinocytes (n = 5 independent samples, mean ± SD). B The estimated amount of leachable comonomers released from the MN patch as detected by RP-HPLC. C Histological staining of rat skin up to 7 days post-patch application. The MN patch was applied on shaven rat skin for 12 h and removed thereafter. The treated area of the skin was excised one (day 1), three (day 3), and seven (day 7) days post-patch removal. Excised skin was stained with Hematoxylin and Eosin (H&E), Masson’s Trichrome (MTC), and CD68 antibodies. Dashed red line boxes show an area with higher magnification, scale bars = 500 μm. No significant signs of skin inflammation were observed across seven days post-patch application. D Photograph and (E) histological analysis of H&E-stained tissue section of rat skin following Trypan blue dye loaded-MN insertion through the stratum corneum. Three biologically independent experiments were performed and representative result is shown.

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