Search

In this work, a microfluidic chip using Au@SiO2 array–based highly active SERS substrates was developed for quantitative detection of squamous cell carcinoma antigen (SCCA) and carcinoembryonic antigen (CEA) associated with cervical cancer. The chip consisted of six functional units with pump-free design, enabling parallel detection of multiple samples in an automatic manner without external pumps and improving the portability. Ag nanocubes (AgNCs) were labeled with Raman reporters and coupled with antibodies (labeling) to prepare SERS tags, while the Au nanoparticle–modified SiO2 microsphere (Au@SiO2) array was conjugated with antibodies (coating) to generate the highly SERS-active capturing substrate. In the presence of target biomarkers, they were captured by SERS tags and capturing substrate, resulting in the formation of "sandwich" structures which were trapped in the detection chamber. As the immune reaction proceeded, a large number of "hot spots" were generated by the proximity of the Au@SiO2 array substrate and AgNCs, greatly amplifying SERS signals. With this chip, the limits of detection of the SCCA and CEA levels in human serum were estimated to be as low as 0.45 pg mL−1 and 0.36 pg mL−1, respectively. Furthermore, the good selectivity and reproducibility of this chip were confirmed. Finally, clinical serum samples were analyzed by this chip, and the outcomes were consistent with those of enzyme-linked immunosorbent assay (ELISA). Thus, the proposed microfluidic chip can be potentially applied for the clinical diagnosis of cervical cancer. [ABSTRACT FROM AUTHOR]

Objective: To explore the microbiological profiles and antibiotic susceptibility patterns of organisms isolated from diabetic foot ulcers so as to provide selection rationales of antibiotics., Methods: A retrospective study was conducted on the microbiological profiles and antibiotic susceptibilities in 754 strains of pathogens isolated from 519 patients with diabetic foot ulcers at our hospital from January 2010 to August 2013. The inter-group data were compared by Chi-square test., Results: There were 322 (62.0%) males and 197 (38.0%) females. Their mean age was (67.7 ± 12.3) (30-93) years, duration of diabetes 10 (0-40) years, duration of lower-limb lesion 1.0 (0.0-72.0) months and HbA1c (9.09% ± 2.28%). Among 444 (85.5%) cases, a total of 754 strains of pathogens were isolated. Gram-positive aerobes were the most frequently isolated (47.3%, 357 strains) and followed by gram-negative aerobes and fungus (40.3% vs 12.3%, 304 vs 93 strains respectively). With rising Wagner's grades, bacterial floras transformed from Gram-positive cocci to Gram-negative rods while fungus and composite infections increased. And 122 strains were of multi drug resistant organisms (MDRO). Among 357 strains of Gram-positive bacteria, Staphylococcus aureus, Staphylococcus epidermidis and Enterococcus faecalis were dominating floras. Staphylococcus was highly resistant to penicillin G, erythromycin, and oxacillin while vancomycin and linezolid were the most effective agents against gram-positive bacteria. Among 304 strains of gram-negative bacteria, enterobacteria were the most prevalent, including 48 strains of Escherichia coli, 34 strains of Proteus mirabilis and 31 strains of Proteus vulgaris. And there were 29 strains of Pseudomonas aeruginosa. Enterobacteria were highly resistant to ampicillin, followed by bactrim and furadantin while meropenem, imipenem, piperacillin/sulbactam, sulperazone and cefepime were the most effective agents. The predominant fungus was Blastomyces albicans., Conclusions: In patients with severe diabetic foot ulcers, Gram-negative rods predominate while the prevalence of fungus and composite infections increases. Vancomycin and imipenem maintain highly antibacterial activity. It is essential to pay attention to pathogen survey and use antibiotics more rationally.