On-chip dual detection of cancer biomarkers directly in serum based on self-assembled magnetic bead patterns and quantum dots.

A sandwich immunoassay method for rapid detection of dual cancer biomarkers in serum on a magnetic field controllable microfluidic chip (MFCM-Chip) was established. A nickel pattern was used to generate high magnetic field gradients to increase the magnetic force on the superparamagnetic beads (SPMBs), which enabled the rapid generation of controllable SPMB patterns in microfluidic channels. The SPMB patterns could keep stable during the fast continuous washing process even at a flow rate of 50 µL/min. This approach demonstrated excellent specificity because the fast continuous washing could remove non-specifically adsorptive contaminants more efficiently than fixed volume batch washing. This approach was used to simultaneously detect carcinoma embryonic antigen (CEA) and α-fetoprotein (AFP) directly in serums. The whole on-chip detection was finished within 40 min, which was much faster than conventional enzyme-linked immunosorbent assay (ELISA) method. High luminescent streptavidin modified QDs (SA-QDs) were used as fluorescence indicators, and the detection limits were 3.5 ng/mL and 3.9 ng/mL for CEA and AFP, respectively. The linear ranges were from 10.0 ng/mL to 800.0 ng/mL. With the high sensitivity, high selectivity and short assay time, this approach could be used for rapid, high throughput detection of cancer biomarkers in clinical trials.

Zirconium arsenate-modified silica nanoparticles for specific capture of phosphopeptides and direct analysis by matrix-assisted laser desorption/ionization mass spectrometry.

In this paper, we report, as far as we are aware, the first use of zirconium arsenate-modified silica nanoparticles (ZrAs-SNPs) for specific capture of phosphopeptides, followed by matrix-assisted laser desorption/ionization mass spectrometric (MALDI MS) analysis. Under the optimized enrichment conditions, the efficiency and specificity of ZrAs-SNPs were evaluated with tryptic digests of four standard proteins (α-casein, ß-casein, ovalbumin, and bovine serum albumin) and compared with those of titanium arsenate-modified silica nanoparticles (TiAs-SNPs). The results showed that more selective enrichment of multiply phosphorylated peptides was observed with ZrAs-SNPs than with TiAs-SNPs whereas TiAs-SNPs resulted in slightly better recovery of singly phosphorylated peptides. ZrAs-SNPs were chosen for direct capture of phosphopeptides from diluted human serum of healthy and adenocarcinoma individuals. Our experimental profiling of serum phosphopeptides revealed that the level of phosphorylated fibrinogen peptide A was up-regulated in the serum of adenocarcinoma patients in comparison with healthy adults. This suggests the possibility of using ZrAs-SNPs for discovery of biomarkers of the pathogenesis process of tumors.

Quantum dots-based double-color imaging of HER2 positive breast cancer invasion.

It has been well recognized that human epidermal growth factor receptor 2 (HER2) level in breast cancer (BC) is closely related to the malignant biologic behaviors of the tumor, including invasion and metastasis. Yet, there has been a lack of directly observable evidence to support such notion. Here we report a quantum dots (QDs)-based double-color imaging technique to simultaneously show the HER2 level on BC cells and the type IV collagen in the tumor matrix. In benign breast tumor, the type IV collagen was intact. With the increasing of HER2 expression level, there has been a progressive decrease in type IV collagen around the cancer nest. At HER2 (3+) expression level, there has virtually been a total destruction of type IV collagen. Moreover, HER2 (3+) BC cells also show direct invasion into the blood vessels. This novel imaging method provides direct observable evidence to support the theory that the HER2 expression level is directly related to BC invasion.

[Expression of human papillomavirus type 16/18 in human cervical carcinomas by the quantum dot fluorescent in-situ hybridization].

OBJECTIVE: To investigate fluorescence in situ hybridization labeled with quantum dots (QDs) for the detection of human papillomavirus 16/18 (HPV16/18) infection in cervical carcinoma patients. METHODS: A total of 80 biopsy samples of squamous carcinoma of cervix were assayed for HPV 16/18 infection by using quantum dot labeled fluorescent in situ hybridization (QD-FISH) and chromogenic in situ hybridization (CISH) techniques, respectively. The results obtained by using two different methods were statistically analyzed. RESULTS: The positive rate for HPV16/18 by QD-FISH was 88.8% (71/80), higher than that (80.0%) by CISH, however, the result was statistically not significant (P=0.127). The positive detection rates for HPV16/18 by using both methods increased coincidentally with raising of the tumor grading stage. CONCLUSION: The sensitivity and specificity of HPV infection detectable by QD-FISH is higher than that by the CISH technique.

Detection of EBV in nasopharyngeal carcinoma by quantum dot fluorescent in situ hybridization.

AIMS: Nasopharyngeal carcinoma (NPC) is a common cancer in Southeast Asia and is frequently associated with Epstein-Barr virus (EBV) infection. The primary aim of this study was to improve the method of EBV detection by exploring quantum dots in FISH detection, and compare QD-based FISH with conventional ISH. MATERIALS AND METHODS: Biopsy specimens were retrospectively retrieved from 35 NPC patients as paraffin-embedded tissue blocks. QD-FISH was developed to detect the presence of EBV encoded small RNA (EBER) using biotin-labeled EBER oligonucleotide probe indirectly labeled with streptavidin-conjugated quantum dots. Conventional ISH was also performed using a commercial kit to assess concordance between the two methods. RESULTS: All the 35 NPC cases were nonkeratinizing carcinoma (7 differentiated and 28 undifferentiated subtypes). EBER-positive signals were detected in 91.43% (32/35) and 80% (28/35) cases by QD-FISH and ISH, respectively. There was no significant difference in the number of EBER-positive cases by the two methods. A moderate concordance was found between QD-FISH and ISH for EBER status (κ=0.55). Four EBER-negative cases by ISH showed EBER-positive signals when detected by QD-FISH. CONCLUSIONS: EBV is closely associated with NPC in Chinese patients. QD-FISH is a novel effective method for EBER detection, and has a moderate concordance with conventional ISH.

The quantitative detection of total HER2 load by quantum dots and the identification of a new subtype of breast cancer with different 5-year prognosis.

Accurate classification is fundamental for breast cancer (BC) personalized care. Current BC classification based on the either traditional morphological staging or molecular signatures seems inefficient to reveal the"true"behaviors of invasive BC evolution. An appropriate approach combining the macro- and micro-pathologic information might be more useful academically as well as clinically. Here we explore a holistic approach by integrating a key molecular prognostic indicator of BC, HER2, with quantitative determination using quantum dots (QDs)--based nanotechnology and spectral analysis, and a key macropathologic indicator, tumor size, resulting a new indicator, total HER2 load. This indicator might better reveal BC heterogeneity and new subtypes of BC with different 5-year disease-free survival compared with current methods, which could be helpful in formulating a more personalized targeted therapy for BC. Furthermore, this mode integrating macro- and micro-pathological indicators might help gain new insights into invasive BC biological behaviors.

Quantum dots-based immunofluorescence technology for the quantitative determination of HER2 expression in breast cancer.

HER2 detection is important for breast cancer (BC) treatment and prognosis, but the detection methods currently used have some disadvantages. Quantum dots (QDs)-based probes provide a potentially important new method for HER2 detection in clinical practice. This potential is examined in this paper. A QDs HER2 probe kit and QDs image acquisition and analysis software were developed and applied to 94 clinical samples of BC. Compared to conventional immunohistochemistry techniques, this method provided a superior accurate and sensitive method for the detection of HER2 in clinical breast cancer diagnosis.

Evidence of human papilloma virus infection and its epidemiology in esophageal squamous cell carcinoma.

AIM: To look for the evidence of human papilloma virus (HPV) infection in esophageal squamous cell carcinomas (ESCC) and to investigate the potential role and epidemiology of HPV infection in the pathogenesis of esophageal carcinomas in Henan emigrants. METHODS: Papilloma virus(PV) and HPV were determined by Ultrasensive S-P immunohistochemistry (IHC) and in situ hybridization (ISH)in esophageal carcinoma tissues (82 cases) and the normal mucosa (40 cases). RESULTS: IHC revealed that the positive rate of PV was 75.0%, 68.18% and 72.5% respectively while the HPV (16/18-E6) positive rate was 45.0%,36.36%, 37.5%, respectively in esophageal carcinoma tissue specimens from Henan emigrants,the local citizens and patients in Hubei Cancer Hospital. The PV and HPV (16/18-E6) were negative in all normal esophageal mucosa specimens. No correlation was found between HPV in esophageal squamous cell carcinoma tissues and in grade 1-3 esophageal squamous cell carcinoma cells. In situ hybridization showed that the HPV (16/18) DNA positive rate was 30.0%, 31.8%, 25.0%, respectively in the 3 groups of samples. No positive hybridization signal was found in 40 normal esophageal mucosa specimens. The positive rate of HPV (16/18) DNA in the esophageal carcinoma specimens was significantly higher than that in normal mucosa specimens (P<0.05). The positive rate was not different among the 3 groups of esophageal carcinoma tissue specimens (P>0.05). CONCLUSION: HPV infection is high in esophageal carcinoma of Henan emigrants, local residents and patients in Hubei Cancer Hospital.HPV is closely related with esophageal squamous cell carcinoma. HPV infection may play an important role in esophageal squamous cell carcinoma.

[DNA content and its correlation with biological behavior of non-small cell lung cancer].

OBJECTIVE: To analyze the relationship between DNA content and biological behavior and its prognostic significance in non-small cell lung cancer. METHODS: Tumor DNA content was determined by flow cytometry in the specimens from 58 patients with resected non-small cell lung cancer. The DNA content of each cell subpopulation was expressed as the DNA index (DI), and an internal standard was provided by the normal pulmonary parenchymal cells in the same specimen. The prognostic value of DNA content in non-small cell lung cancer was assessed by Cox's model analysis. RESULTS: In qualitative analysis, there was no relationship between DNA ploidy (diploidy or aneuploidy) and the following factors: tumor size, metastasis of lymph node, clinical stage, pathologic type, pathologic grade or survival. In quantitative analysis, high DNA index was observed in tumor size > 3 cm, metastasis of lymph node, stage III/IV, adenocarcinoma and shorter survival, which was statistically significant. Cox's model analysis showed that DNA index was a prognostic factor in non-small cell lung cancer and DNA index > 2.0 was an independent prognostic factor. CONCLUSION: DNA index analysis is useful for the evaluation of the biological behavior and the prognosis of non-small cell lung cancer.