Covalent Amide-Bonded Nanoflares for High-Fidelity Intracellular Sensing and Targeted Therapy: A Superstable Nanosystem Free of Nonspecific Interferences.

A nanoflare, a conjugate of Au nanoparticles (NPs) and fluorescent nucleic acids, is believed to be a powerful nanoplatform for diagnosis and therapy. However, it highly suffers from the nonspecific detachment of nucleic acids from the AuNP surface because of the poor stability of Au-S linkages, thereby leading to the false-positive signal and serious side effects. To address these challenges, we report the use of covalent amide linkage and functional Au@graphene (AuG) NP to fabricate a covalent conjugate system of DNA and AuG NP, label-rcDNA-AuG. Covalent coating of abundant amino groups (-NH2) onto the graphitic shell of AuG NP efficiently facilitates the coupling with carboxyl-labeled capture DNA sequences through simple, but strong, amide bonds. Importantly, such an amide-bonded nanoflare possesses excellent stability and anti-interference capability against the biological agents (nuclease, DNA, glutathione (GSH), etc.). By accurately monitoring the intracellular miR-21 levels, this covalent nanoflare is able to identify the positive cancer cells even in a mix of cancer and normal cells. Moreover, it allows for efficient photodynamic therapy of the targeted cancer cells with minimized side effects on normal cells. This work provides a facile approach to develop a superstable nanosystem showing promising potential in clinical diagnostics and therapy.

[Expression of Bcl-2 and Bax proteins in rat liver fibrosis model and the role of IFN-gamma].

OBJECTIVE: To study the expression of Bcl-2 and Bax in rat liver fibrosis model induced by CCl4 and the role of IFN-gamma. METHODS: Liver fibrosis was induced in rats by subcutaneous injection of CCl4. The rats were divided into fibrosis model group, Bie-Jia-Ruan-Gan-Tablet treatment group and IFN-gamma treatment group (0.2 MU.kg.d, i. m. for 12 weeks), and another 10 rats without any treatment were used as normal control. Bcl-2 and Bax proteins expression were detected by immunohistochemistry. RESULTS: Bcl-2 was expressed weakly in the homogenate of hepatocytes and hepatic sinusoid in normal control rats, and it was expressed stronger in fibrous septae, portal area, hepatic sinusoid, the homogenate and membrane of hepatocytes and central vein in fibrosis model rats (3.87%+/-2.37% vs 9.46%+/-4.29%, t=2.83, P<0.05). Bax was expressed slightly in central vein and the hepatic sinusoid around, and it was expressed stronger in the homogenate of hepatocytes, hepatic sinusoid, fibrous septae, membrane of hepatocytes and epithelial cells of bile duct (3.50%+/-1.88% vs 9.80%+/-3.75%, t=3.72, P<0.01). Compared with that in fibrosis model rats, the expression of Bax was significantly lower in rats treated with IFN-gamma (9.80%+/-3.75% vs 5.85%+/-2.35%, t=2.98, P<0.01), but the expression of Bcl-2 was not significantly different (t=1.49, P>0.05), however it was significantly lower in fibrous septae in IFN-gamma-treated group than in model group (6.58%+/-4.13% vs 9.46%+/-4.29%, t=2.80, P<0.05). CONCLUSION: The expression of Bcl-2 and Bax increases in liver fibrosis model rats, and IFN-gamma can promote myofibroblasts apoptosis