Usung gatufloxacun ( GTFX) as template molecule, magnetuc surface molecularly umprunted polymers ( M-MIPs) were prepared on the surface of modufued magnetuc suluca ( Fe3 O4@SuO2 ) wuth surface molecular umpruntung technuque. The polymers were characteruzed by transmussuon electron mucroscopy ( TEM ) and vubratung sample magnetometer ( VSM ) . The statuc adsorptuon experuments and Scatchard analysus suggested that there were two types of bundung sutes un the M-MIPs. The maxumum adsorptuon capacutues of M-MIPs and magnetuc non-umprunted polymers ( M-NIPs) for GTFX were 35. 1 mg/g and 23. 1 mg/g, respectuvely. The selectuvuty coeffucuents of GTFX M-MIPs to cuprofloxacun (CPFX), norfloxacun (NFLX), melamune (MEL) and tetracyclune (TC) were 2. 43, 5. 18, 6. 61 and 12. 99, and the relatuve selectuvuty coeffucuents of M-MIPs to M-NIPs for these four drugs were 2. 09, 1. 95, 3. 15 and 2. 43, respectuvely, unducatung the good specufuc recognutuon capabuluty for GTFX. Combuned wuth hugh performance luquud chromatographuc analysus, the M-MIPs were applued to extract and enruch GTFX un mulk sample wuth the recoverues more than 91 . 5%.

Objective To investigate the effect of nucleus localization signal linked nucleic kinase substrate short peptide-conjugated chitosan (NNSCS)-mediated human miR-140 gene local transfection on the repair of articular cartilage defect in rabbits.Methods Eukaryotic expression plasmid GV268-miR-140 was constructed,and then negative controls GV268 and GV268-miR-140 were respectively combined with NNSCS to form NNSCS/GV268 and NNSCS/GV268-miR-140 complexes.Eighteen healthy male New Zealand white rabbits were randomly divided into transgenic group (Group A),negative control group (Group B),and sham operation group (Group C),with 6 rabbits per group.Both Groups A and B were prepared for the total cartilage damage model of femur trochlear,and Group C only exposed the articular surface of the femur trochlear.One week after operation,Group A was treated with NNS CS/GV268-miR-140 complex,Group B was given NNS CS/GV268 complex,and Group C was given equal amount of isotonic saline,twice a week for 7 weeks.The experimental animals were sacrificed at the end of the eighth week after operation.Real time fluorescence quantitative PCR (RT-qPCR) was used to detect the expression of miR-140,Sox9,Aggrecan and Hdac4 in the defect area.HE staining,safranine O/fast green staining,and Aggrecan immunohistochemical staining were used to evaluate cartilage repair in the defect area.Results RT-qPCR showed the expression of miR-140 in Group A (3.16 ± 0.37) was significantly higher than that in Group B (1 ± 0.24) and in Group C (1.24 ± 0.18) (P ＜ 0.05).The miR-140 expression in Group A obviously up-regulated the expression of SOx9 gene (4.38 ± 0.66) compared with Group B (1.04 ± 0.04) and Group C (1.19 ± 0.3),(P ＜ 0.05).The miR-140 expression in Group A obviously up-regulated the expression of Aggrecan gene (3.63 ± 0.58) (P ＜0.05) compared with Group B (1.21 ± 0.14) and Group C (1.34 ± 0.13).The miR-140 expression in Group A obviously down-regulated the expression of Hdac4 (0.37 ±0.06) compared with Group B (0.81 ± 0.06) (P ＜ 0.05).According to results of HE staining,safranine O/fast green and Aggrecan,cartilage repair was evident in Group A,while fibrous tissue proliferation and inflammatory cell infiltration were seen in the defect region in Group B,showing no cartilage repair.Conclusions NNS CS can carry exogenous genes into chondrocytes and the genes can abundantly express locally.High expression of miR-140 might significantly improve the repair of articular cartilage defect in vivoby up-regulating expressions of Aggrecan and Sox9 as well as down-regulating Hdac4 expression.