This study inquired about the influences on the gene delivery efficiency of polyethylenimine. pSVbeta plasmids were transferred into COS-7 and NIH3T3 cells with polyethylenimine. Influences of plasmids factor, albumin, serum, cell density, operation methods and polyethylenimine/DNA preserve factors on transfection efficiency were investigated. Inhibitors of biological activities in plasmids could be removed by ultrafiltration with cutoff molecular weight of 3000 or 10000. Linear plasmids lowered transfection efficiency. Serum and albumin in the culture medium decreased the transfection efficiency of polyethylenimine/DNA. Cell density was associated with PEI/DNA transfection efficiency. Incubation of PEI/DNA complexes with the cells for 8 h and then aspiration for removal of the complexes could obtain an optimal transfection effect. Freezing of PEI/DNA complexes significantly decreased transfection efficiency. In conclusion, polyethylenimine could obtain optimal and reduplicate transfection results by controlling related factors.
3T3 Cells ; Animals ; COS Cells ; Cercopithecus aethiops ; DNA ; genetics ; Genetic Vectors ; genetics ; Mice ; Plasmids ; genetics ; Polyethyleneimine ; chemistry ; Transfection ; Ultrafiltration

Objective To investigate different antigens detected by a novel labelled reagent‐quantum dots(QDs) in the colorectal cancer tissues microarray(TMA) .Methods Depend on QDs streptavidin conjugate(QDs‐SA) combined specially with biotinylation IgG ,immune of luorescent histochemistry was utilized to examine expression of K‐ras ,matrix‐remodeling associated 5(MXRA5) proteins in the colorectal cancer TMA ,where the protein accurate location was observed .Results K‐ras ,matrix‐remodeling associ‐ated 5(MXRA5) proteins were high expressed in colorectal cancer tissue and located accurately in the cell membrane and nucleus of colorectal cancer cells ,respectively .Conclusion QDs exhibit excellent photostability ,broad emission spectrum and long fluorescence lifetime .Modified with streptavidin could accurately detect different protein locations in the colorectal cancer TMA .This is a novel approach for studying targeted imaging of colorectal cancer in vivo and vitro clinical diagnosis .

Objective To investigate the application valve of real-time fluorescence quantitative polymerase chain reaction(RT-PCR) for the detection of tumor M2-pyruvate kinase(tM2-PK) DNA in patients with colorectal cancer(CRC).Methods Fragment of tM2-PK DNA(162 bp) was amplified and inserted into PGM-T vector to construct recombinant plasmid,which was used to develop RT-PCR method.Sensitivity,specificity and repeatability of RT-PCR for the detection of tM2-PK were analyzed.From Jan.2014 to Jun.2016,200 CRC patients and 100 healthy subjects were enrolled and detected for fecal and serum tM2-PK DNA by using RT-PCR,and the detected results were compared with those detected by using enzyme linked immunosorbent assay(ELISA).Results Recombinant plasmid was successfully constructed,which was certified by sequencing.The sensitivity of RT-PCR for the detection of tM2-PK DNA was 10 copy/mL,with high specificity and 0.3%-2.9% of coefficient of variation.In patients,the positive rate of fecal tM2-PK DNA,detected by RT-PCR,was 92.50%,and that of ELISA to detect tM2-PK was 80.00%.Fecal and serum levels of tM2-PK were correlated with the pathologic stages of tumour.Conclusion Self-established RT-PCR could be specificity and sensitivity for the detection of fecal tM2-PK,which could be used for the early diagnosis of CRC.