The studies included in this review evaluated a variety of different TNT applications, and the data could not be analyzed quantitatively due to heterogeneity. However, the findings of the studies are summarized to provide an overview of the progress and role of TNT. According to the studies included, TNT is effective in the following aspects:
1. Tissue Nano-transfection enabled the delivery of Ascl1, Brn2, and Myt1l (TNTABM), which converted skin fibroblasts into neuronal cells. TNTABM enriched skin stroma, increased NGF and other co-regulated neurotrophic factors such as Nt3, and prevented PGP9.5+ loss in diabetic mice. Thus, using TNT to deliver certain reprogramming factors can protect pre-existing nerve fibers from loss in diabetic patients (4).
2. A TNT-based topical CRISPR/dCas9 strategy was used to develop chimeric versions of dCas9 fused with TET to achieve TP53 demethylation.TP53 demethylation improved wound closure. This proves that TNT can be employed to improve topical wound closure (7).
3. TNT can be used to label exosomes by delivering three plasmids encoding for CD9, CD63, and CD81 with an "in frame" GFP reporter, resulting in GFP expression in exosomes and allowing these exosomes to be easily identified and isolated for further processing(8).
4. As in the mouse tail lymphoma model, TNT can be used to deliver genetic cargo to the site of lymphatic injury. TNT holds great promise for the delivery of gene-based therapies (9).
5. TNT can be used to deliver reprogramming factors genes Etv2, Foxc2, and Fli1 (EFF) to crushed nerves, which results in increased vascularity and better recovery. Tissue Nano transfection, when compared to Bulk Electroporation (BEP), does not hinder toe-spread and pinprick response and does not affect electrophysiological parameters, whereas BEP can cause nerve damage and increase macrophage overexpression(10).
6. TNT is used to treat ischemic stroke in mice by delivering reprogramming factors (Etv2, Foxc2, and Fli1 (EFF)) which are vasculogenic cell therapies. These treatment methods lead to increased vascularity and revealed infract resolution, indicating that TNT is a particularly promising future approach to treat ischemic stroke (11).
7. TNT was used to deliver reprogramming factors to the skin in 2 injury-induced ischemia mouse models, which resulted in the formation of vascular networks that successfully anastomosed with the systemic circulation, recovered tissue, and managed to rescue the entire limb of mice, implying that TNT could be used to rescue necrotizing tissue (12).TNT could also be employed to develop tissue early intervention measures to deal with severe tissue ischemia since ischemic tissue can be saved using polymerized hemoglobin (PolyHb)-based oxygen Nanocarriers and Tissue Nano-Transfection (TNT) (6).