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Objective To fabricate an immunofluorescence probe system of carbon dots conjugated antibody based on antigen-antibody reaction principles.Methods A green one-step microwave assisted pyrolysis method was applied to preparing fluorescent carbon dots (CDs) using aminoglucose as carbon source and the obtained CDs were conjugated with antibody via EDC/NHS reactions to build CDs based fluorescent probe.Furthermore,the properties of CDs and CDs based probe system were evaluated by Fourier transform infrared (FTIR) spectra,transmission electron microscopy (TEM),UV-vis absorption and so on.Results The as-prepared CDs showed excellent fluorescence and hydrophilicity and CDs based immunofluorescence probe exhibited the capability of quick detection of E.coli O157:H7.Cinclusion Fluorescent CDs as one new emerging environment-friendly nanomaterial has great potential in biosensors.
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Objective To evaluate the detection rates of colorectal polyps and cancer in the elderly and characterize the pathological features of the colorectal neoplasm in DongLi District in Tianjin.Method Totally,46 743 subjects aged 60-74 were recruited from the national colorectal cancer screening program,including subjects registered from November 2012 to April 2013 in DongLi District in Tianjin.Each subject completed a questionnaire and a fecal occult blood test.Colonoscopies were conducted in 434 subjects with high risk for colorectal cancer.Results Among all the subjects,2 880 were at high risk for colorectal cancer which accounts for 6.16％ (2 880/46 743) of the total subjects.Among the subjects who underwent the colonoscopy,165 (men:105,women:60) were colorectal polyps accounting for 5.73％ (165/2 880)in the total risk,with 51 subjects (1.77％) advanced neoplasms and 4 subjects (0.14％) cancer.The detection rates of colorectal polyps is 0.35％ (165/46 743),and colorectal cancer is 8.6/105(4/46 743).More polyps were found on the left colon compared with the right.More tubular adenoma was found compared with the other pathological types.Most of the polyps were smaller than 0.5 cm.Colorectal polyps and advanced neoplasms were more frequent in men than women [45.45％ (105/231) vs 29.56％ (60/203),16.02％ (37/231) vs 6.90％ (14/203),all P ＜ 0.01].Multiple polyps (P ＜ 0.05) and polyps with diameter larger than 1.0 cm (P ＜ 0.01) were more often in men than in women.Men tended to have more colorectal polyps in right colon and higher detection rate for moderate or sever atypical hyperplasia than women(all P ＜ 0.05).Conclusion There is a higher incidence of colorectal polyps in the elderly.It is important to establish the national sequential colorectal cancer screening program for the early diagnoses of colorectal polyps and cancer in the elderly.