All-carbon sandwich-type self-powered biosensor for ultrasensitive detection of femtomolar miRNA-141.

The latest research shows that the expression level of microRNA-141 can predict the number of prostate cancer cells in the human body and has become an important biomarker. In this paper, an all-carbon sandwich self-powered biosensor based on graphene and carbon cloth is constructed for the highly sensitive detection of the prostate tumor marker miRNA-141. First, gold nanoparticles modified carbon cloth is applied for substrate electrode, and bilirubin oxidase is then immobilized on it to prepare the biocathode of the biofuel cell. Then, aptamer 1 is immobilized on gold nanoparticles-modified carbon cloth as the electrode substrate. The bioconjugate is prepared by immobilizing the aptamer 2-glucose oxidase complex on gold nanoparticles/graphene. In the biofuel cell-based self-powered sensing system, when the target microRNA-141 is present, it undergoes complementary base pairing with aptamer 1 and aptamer 2, and the bioconjugates are immobilized on the anode to form the sandwich structure. The enzyme on the anode undergoes an oxidation reaction to catalyze the reduction of oxygen, and the electrochemical respond of the system increases significantly. The results show that the concentration of microRNA-141 is proportional to the open-circuit voltage value ranging from 0.0001 to 1000 pmol/L with a detection limit of 50 amol/L (S/N = 3). The method has high sensitivity and excellent selectivity and can be applied to sensitively detect tumor marker microRNA-141 in biological matrix.

[Clinical investigation on intravesical instillation of high-dose pirarubicin during perioperative period to prevent bladder carcinoma recurrence].

OBJECTIVE: To evaluate the efficacy and safety of intravesical instillation of high-dose pirarubicin during perioperative period to prevent bladder carcinoma recurrence. METHODS: A prospective randomized controlled clinical trial was carried out. A total of 120 patients with bladder transitional cell carcinoma (TNM I-II) underwent partial cystectomy or transurethral resection of bladder tumour were randomly divided into 2 groups, which were chosen from the patients were hospitalized during June 2003 to May 2009. There were 62 patients were in group A and 58 patients were in group B. In group A, intravesical instillation of high-dose pirarubicin during perioperative period was conducted. In group B, intravesical perfusion of pirarubicin was performed regularly after operation. All the patients were followed up in order to record the relapse rates and adverse reaction. RESULTS: No significant difference was found between group A and group B from gender, age, pathological stage and operation methods (P > 0.05). The recurrence rates were 8.1% in group A, and 20.7% in group B. The adverse effect rates of urethrostenosis in group A and group B were 3.2% and 18.9%. The adverse effect rates of cystic stimulation including irritation signs of bladder and hematuria in group A and group B were 4.8% and 27.6%. There were significant differences in recurrence rates and adverse effect rates between the two groups (P > 0.05). CONCLUSION: Intravesical instillation of high-dose pirarubicin during perioperative period is an effective procedure for the prevention of bladder cancer recurrence.