Irreversible Bonding of Polydimethylsiloxane-Lithium Niobate using Oxygen Plasma Modification for Surface Acoustic Wave based Microfluidic Application: Theory and Experiment.

Acoustic microfluidic chips, fabricated by combining lithium niobate (LiNbO3 ) with polydimethylsiloxane (PDMS), practically find applications in biomedicine. However, high-strength direct bonding of LiNbO3 substrate with PDMS microchannel remains a challenge due to the large mismatching of thermal expansion coefficient at the interface and the lack of bonding theory. This paper elaborately reveals the bonding mechanisms of PDMS and LiNbO3 , demonstrating an irreversible bonding method for PDMS-LiNbO3 heterostructures using oxygen plasma modification. An in-situ monitoring strategy by using resonant devices is proposed for oxygen plasma, including quartz crystal microbalance (QCM) covered with PDMS and surface acoustic wave (SAW) fabricated by LiNbO3 . When oxygen plasma exposure occurs, surfaces are cleaned, oxygen ions are implanted, and hydroxyl groups (-OH) are formed. Upon interfaces bonding, the interface will form niobium-oxygen-silicon covalent bonds to realize an irreversible connection. A champion bonding strength is obtained of 1.1 MPa, and the PDMS-LiNbO3 acoustic microfluidic chip excels in leakage tests, withstanding pressures exceeding 60 psi, outperforming many previously reported devices. This work addresses the gap in PDMS-LiNbO3 bonding theory and advances its practical application in the acoustic microfluidic field.

Retrospective analysis of 4761 cases who underwent amniocentesis in southeast China.

The aim of this study was to examine the clinical and cytogenetic results of 4761 amniocentesis (AS) cases retrospectively in our clinic in southeast China. The prenatal diagnosis indications, detected chromosomal anomalies and the detection rate of chromosomal abnormalities were studied in 4761 patients who underwent AS between June 2014 and July 2016 retrospectively. Chromosomal abnormality was detected in 137 (2.88%) of the 4761 samples (89.1% numerical, 10.9% structural). The most frequent numerical chromosomal abnormality was trisomy 21 (59.0%). Clinically insignificant polymorphisms were the most frequent structural changes (n = 284). In our study, the frequency and proportion of abnormal karyotypes varied substantially across different maternal AS indications. Impact statement What is already known on this subject: Several studies on amniocentesis indications and results have been reported from China and from other countries. It has been known that the most common indications were the increased risk at maternal serum screenings (MSS) and advanced maternal age (AMA). What the results of this study add: In our study we make a conclusion that the indications and results of AS cases from our centre indicated the significance of genetic screening. What the implications are of these findings for clinical practice and/or further research: Our data could offer informative data for proper prenatal genetic counselling of pregnant women and their partners in Wuxi, China.

Novel rapid molecular diagnosis of fetal chromosomal abnormalities associated with recurrent pregnancy loss.

INTRODUCTION: Labor-intensive karyotyping is used as the reference standard diagnostic test to identify copy number variants (CNVs) in the fetal genome after recurrent pregnancy loss. Our aim was to present and evaluate a novel molecular assay called CNVplex that could potentially be used as an alternative method to conventional karyotyping for diagnosing fetal chromosomal abnormalities associated with recurrent pregnancy loss. MATERIAL AND METHODS: Using karyotyping as the reference standard, CNVplex was performed to identify fetal chromosomal abnormalities in the chorionic villus samples from 76 women experiencing at least two pregnancy losses. Its diagnostic accuracy, sensitivity, and specificity were evaluated to detect aneuploidies associated with recurrent pregnancy loss. Turnaround time and costs of CNVplex were also measured. RESULTS: Diagnostic accuracy of CNVplex in aneuploidies that are associated with recurrent pregnancy loss was 1.0 (95% CI 0.94-1.0), sensitivity was 100% (95% CI 0.89-1.0), and specificity was 100% (95% CI 0.875-1.0). Diagnostic accuracy of CNVplex was similar to that of karyotyping. Both karyotyping and CNVplex assay detected 27 autosomal trisomies, three 45,X monosomies, and three polyploidies. CNVplex also detected additional novel structural abnormalities of the fetal genome. Compared with karyotyping, CNVplex significantly (p = 0.001) reduced the waiting time by 13.98 days (95% CI 13.88-14.08) and the cost by US $241 (95% CI 234.53-247.47). CONCLUSIONS: CNVplex is a novel effective assay for diagnosing fetal chromosomal abnormalities associated with recurrent pregnancy loss. In the routine clinical work-up of recurrent pregnancy loss, diagnostic accuracy of CNVplex is comparable to that of conventional karyotyping but it requires less waiting time and has lower cost.