Enzyme-conjugated hybridization chain reaction for magneto-controlled immunoassay of squamous cell carcinoma antigen with pH meter

A nanoparticle-based potentiometric immunoassay was designed for the sensitive detection of squamous cell carcinoma antigen(SCCA;cervical carcinoma marker) on a portable pH meter coupling enzyme-labeled hybridization chain reaction(HCR) with two alternating hairpin DNA probes for the signal amplification. Initially, a sandwich-type immunoreaction was carried out between anti-SCCA capture antibody-conjugated magnetic bead and detection antibody/initiator strand-coated gold nanoparticle(AuNP). Then, the HCR reaction was readily executed between two glucose oxidase(GOx)-labeled hairpins through the initiator strand to form numerous GOx concatamers on the AuNP via the long nicked double-helix. The concatenated GOx oxidized glucose into gluconic acid and hydrogen peroxide, thus resulting in the pH change of the detection solution on a handheld pH meter. Several labeling protocols including GOx-antibody, GOx-AuNP-antibody and GOx-HCR-AuNP-antibody were investigated for detection of target SCCA, and improved analytical features were obtained with the immune-HCR assay. Under optimum conditions, the immune-HCR assay exhibited good pH responses for the determination of SCCA at a concentration as low as 5.7 pg/mL. Additionally, the immune-HCR assay had good precision and reproducibility, high specificity, and acceptable accuracy for analyzing human serum specimens.

Epidemiological studies of women under age 30 infectedwith human papillomavirus

The aim of this paper was to investigate the prevalence of human papilloma virus(HPV)infection in women under 30 years old with cervical intraepithelial neoplasia(CIN)or cervical cancer,in order to provide a basis for cervical cancer prevention and treatment.We recruited 2052 female cases from the education system in Futian District,Shenzhen city,from April 2006 to April 2008,with age ranging from 22 to 60 years old.Second-generation hybrid capture test was done for detection of female genital tract HPV and cervical colposcopy for screening CIN or cervical cancer.The prevalence of HPV and cervical precancerous lesions or cervical cancer was evaluated in different age groups of women.The HPV positive rate was 247/2052(12.00%),and 35/2052(1.71%)of the cases were≥CIN I by pathological diagnosis.In the 22–29-year-old age group,there were 291 cases,including 39 HPV-positive cases(13.40%)and one case of pathological diagnosis≥CIN I(0.34%),and there were 1761 cases in the 30–60-year-old age group,including 208 HPV-positive cases(11.81%)and 34 cases of pathological diagnosis≥CIN I(1.93%).The HPV-positive rate of 22–29-year-old age group was higher than that of 30–60-year-old age group,but the difference was not significant(χ2=0.5967,P=0.4398);the CIN and cervical cancer detection rate of the former group was lower than that of the latter one,and the difference was not significant either(χ2=3.7519,P=0.0527).The cases in 30–60-year-old age group were divided intofive age sub-groups,and the HPV-positive rate of the 22–29-year-old age group was compared with the remaining groups,and it was found that the HPV-positive rate of the former group(13.40%)was lower than that of the 40–44-year-old age group(14.70%)but higher than that of the other four groups.Moreover,the difference in the HPV-positive rate between the 22–29-year age group and the 50–60-year-old age group(6.06%)was significant(χ2=5.545,P=0.018),but the difference between the 22–29-year-old age group and each of the other four groups was not significant(P>0.05).In addition,the CIN and cervical cancer detection rate of the 22–29-year-old age group(0.34%)was lower than that of the remainingfive groups,and the difference between the 22–29-year-old age group and the 35–39-year-old age group(2.26%),and between 22–29-year-old age group and 40–44-year-old age group(2.30%)was significant(χ2=4.446,P=0.0035;χ2=4.525,P=0.0363,respectively),but the difference between the 22–29-year-old age group and each of other three groups was not significant(P>0.05).Furthermore,80.00%(28/35)cases of pathological diagnosis≥CIN I and 90.91%(10/11)lesions of pathological diagnosis≥CIN II occurred at 35–49 years of age.For many young women below the age of 30 who were infected with high-risk HPV were one-off infections,so it was not appropriate to recommend HPV detection as cervical precancerous lesions or cancer screening program for women less than 30 years old.The prevention and treatment of cervical cancer should be focused on those women more than 35 years of age.