Nanoparticles are used to solve the current drug delivery problem. We present a high-performance method for efficient and selective action on nucleic acid target in cells using unique TiO2·PL-DNA nanocomposites (polylysine-containing DNA fragments noncovalently immobilized onto TiO2 nanoparticles capable of transferring DNA). These nanocomposites were used for inhibition of human influenza A (H3N2) virus replication in infected MDCK cells. They showed a low toxicity (TC50 ≈ 1800 μg/ml) and a high antiviral activity (>99.9% inhibition of the virus replication). The specificity factor (antisense effect) appeared to depend on the delivery system of DNA fragments. This factor for nanocomposites is ten-times higher than for DNA in the presence of lipofectamine. IC50 for nanocomposites was estimated to be 1.5 μg/ml (30 nM for DNA), so its selectivity index was calculated as ~1200. Thus, the proposed nanocomposites are prospective for therapeutic application.
In this study we examine the possibility that TiO 2 nanoparticles and their conjugates can penetrate into cultivated cells without any special transfection procedures. Oligonucleotides and their derivates were conjugated with the TiO 2 nanoparticles, which were obtained as colloidal solutions at a concentration of TiO 2 0.3M by TiCl 4 hydrolysis. The electronic microscopy of various cell cultures (KCT, Vero, and MDCK) treated with nanoparticle solutions (20 µg/µl) showed that nanoparticles could enter the cells and accumulate in the vacuoles and phagosomes and form inclusions in cytoplasm. Thus, we demonstrated the penetration of TiO 2 nanoparticles and their oligonucleotide conjugates into intracellular space without any auxiliary operations. Most other researches used electroporation techniques for similar purposes [1, 2, 5].
The effect of crab collagenase on the healing of thermal burns of uninfected rats is studied morphologically. The enzyme is applied to the wounds using a polyethylene oxide gel with antibiotics. Protease with antibiotics is more effective than Laevomecol ointment.Proteolytic enzymes, such as trypsin, chymotrypsin, and collagenase, are often used in the treatment of thermal burns to accelerate the rejection of scab and necrotic tissues [2]. An enzymatic agent exhibiting both collagenolytic and caseinolytic activities [3,4] has been prepared from the hepatopancreas of the king crab Paralithodes camtschatica. The reported effect of crab collagenase on wound healing [1] prompted us to investigate the effect of collagenase ointment on the healing of uninfected thermal bum in rats.
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