Smart Carbon Nanotubes with Laser-Controlled Behavior in Gene Delivery and Therapy through a Non-Digestive Trafficking Pathway.

Near-infrared (NIR) laser-controlled gene delivery presents some benefits in gene therapy, inducing enhanced gene transfection efficiency. In this study, a "photothermal transfection" agent is obtained by wrapping poly(ethylenimine)-cholesterol derivatives (PEI-Chol) around single-walled carbon nanotubes (SWNTs). The PEI-Chol modified SWNTs (PCS) are effective in compressing DNA molecules and protecting them from DNaseI degradation. Compared to the complexes formed by PEI with DNA (PEI/DNA), complexes of PCS and DNA that are formed (PCS/DNA) exhibit a little lower toxicity to HEK293 and HeLa cells under the same PEI molecule weight and weight ratios. Notably, caveolae-mediated cellular uptake of PCS/DNA occurs, which results in a safer intracellular transport of the gene due to the decreased lysosomal degradation in comparison with that of PEI/DNA whose internalization mainly depends on clathrin rather than caveolae. Furthermore, unlike PEI/DNA, PCS/DNA exhibits a photothermal conversion ability, which promotes DNA release from PCS under NIR laser irradiation. The NIR laser-mediated photothermal transfection of PCS10K /plasmid TP53 (pTP53) results in more apoptosis and necrosis of HeLa cells in vitro than other groups, and achieves a higher tumor-growth inhibition in vivo than naked pTP53, PEI25K /pTP53, and PCS10K /pTP53 alone. The enhanced transfection efficiency of PCS/DNA can be attributed to more efficient DNA internalization into the tumor cells, promotes detachment of DNA from PCS under the mediation of NIR laser and higher DNA stability in the cells due to caveolae-mediated cellular uptake of the complexes.

IGF-PLGA microspheres promote angiogenesis and accelerate skin flap repair and healing by inhibiting oxidative stress and regulating the Ang 1/Tie 2 signaling pathway.

Random flaps are widely used in the treatment of injuries, tumors, congenital malformations, and other diseases. However, postoperative skin flaps are prone to ischemic necrosis, leading to surgical failure. Insulin-like growth factor- 1(IGF-1) belongs to the IGF family and exerts its growth-promoting effects in various tissues through autocrine or paracrine mechanisms. Its application in skin flaps and other traumatic diseases is relatively limited. Poly (lactic-co-glycolic acid) (PLGA) is a degradable high-molecular-weight organic compound commonly used in biomaterials. This study prepared IGF-PLGA sustained-release microspheres to explore their impact on the survival rate of flaps both in vitro and in vivo, as well as the mechanisms involved. The research results demonstrate that IGF-PLGA has a good sustained-release effect. At the cellular level, it can promote 3T3 cell proliferation by inhibiting oxidative stress, inhibit apoptosis, and enhance the tube formation ability of human umbilical vein endothelial cells (HUVEC) . At the animal level, it accelerates flap healing by promoting vascularization through the inhibition of oxidative stress. Furthermore, this study reveals the role of IGF-PLGA in activating the Angiopoietin-1(Ang1)/Tie2 signaling pathway in promoting flap vascularization, providing a strong theoretical basis and therapeutic target for the application of IGF-1 in flaps and other traumatic diseases.

Preparation of artificial red cell and its application on alleviation of tumor hypoxia.

Hemoglobin-based oxygen carriers were developed as an alternative for blood transfusion. However, the research progress for their further clinic applications was slow in recent several years. Hypoxia is found in most solid tumors, which is responsible for the tumor formation, increased metastasis, drug resistance during therapeutic process as well as poor patient survival. In this work, novel hemoglobin (Hb) loaded nanoliposomes, as artificial red cells for oxygen delivery, were optimized by screening various types of phospholipids and analyzing different mole ratio of phospholipid to cholesterol. The nanoliposomes presented a high encapsulating efficiency to hemoglobin and also significantly enhanced its stability. The obtained hemoglobin loaded nanoliposome (HLL) could be lyophilized for long term storage. HLL did not cause significant cell death in the concentration range of 0-100µg equivalent Hb/mL under normoxia and hypoxia incubation conditions, suggesting the low cytotoxicity and high biocompatibility of HLL. Importantly, HLL could efficiently accumulate into subcutaneous and deep orthotopic tumors, inducing a significant decrease of hypoxia-inducible factors 1α subunits (HIF-1α) in the tumors and remarkably reduced expression of vascular endothelial growth factor (VEGF). The study of acute and chronic toxicity indicated that HLL did not induce obvious damage to main organs of mice after intravenous injections with total Hb dose of 120mg/kg. We presented a promising method for relieving the hypoxia degree in solid tumors and down-regulating HIF-1α protein by directly delivering oxygen into tumors, which will be very helpful for subsequent cancer therapy.