Self-partitioning SlipChip for slip-induced droplet formation and human papillomavirus viral load quantification with digital LAMP

Human papillomavirus (HPV) is one of the most common sexually transmitted infections worldwide, and persistent HPV infection can cause warts and even cancer. Nucleic acid analysis of HPV viral DNA can be very informative for the diagnosis and monitoring of HPV. Digital nucleic acid analysis, such as digital PCR and digital isothermal amplification, can provide sensitive detection and precise quantification of target nucleic acids, and its utility has been demonstrated in many biological research and medical diagnostic applications. A variety of methods have been developed for the generation of a large number of individual reaction partitions, a key requirement for digital nucleic acid analysis. However, an easily assembled and operated device for robust droplet formation without preprocessing devices, auxiliary instrumentation or control systems is still highly desired. In this paper, we present a self-partitioning SlipChip (sp-SlipChip) microfluidic device for the slip-induced generation of droplets to perform digital loop-mediated isothermal amplification (LAMP) for the detection and quantification of HPV DNA. In contrast to traditional SlipChip methods, which require the precise alignment of microfeatures, this sp-SlipChip utilized a design of “chain-of-pearls” continuous microfluidic channel that is independent of the overlapping of microfeatures on different plates to establish the fluidic path for reagent loading. Initiated by a simple slipping step, the aqueous solution can robustly self-partition into individual droplets by capillary pressure-driven flow. This advantage makes the sp-SlipChip very appealing for the point-of-care quantitative analysis of viral load. As a proof of concept, we performed digital LAMP on an sp-SlipChip to quantify human papillomaviruses (HPVs) 16 and 18 and tested this method with fifteen anonymous clinical samples

Self-partitioning SlipChip for slip-induced droplet formation and human papillomavirus viral load quantification with digital LAMP

Human papillomavirus (HPV) is one of the most common sexually transmitted infections worldwide, and persistent HPV infection can cause warts and even cancer. Nucleic acid analysis of HPV viral DNA can be very informative for the diagnosis and monitoring of HPV. Digital nucleic acid analysis, such as digital PCR and digital isothermal amplification, can provide sensitive detection and precise quantification of target nucleic acids, and its utility has been demonstrated in many biological research and medical diagnostic applications. A variety of methods have been developed for the generation of a large number of individual reaction partitions, a key requirement for digital nucleic acid analysis. However, an easily assembled and operated device for robust droplet formation without preprocessing devices, auxiliary instrumentation or control systems is still highly desired. In this paper, we present a self-partitioning SlipChip (sp-SlipChip) microfluidic device for the slip-induced generation of droplets to perform digital loop-mediated isothermal amplification (LAMP) for the detection and quantification of HPV DNA. In contrast to traditional SlipChip methods, which require the precise alignment of microfeatures, this sp-SlipChip utilized a design of “chain-of-pearls” continuous microfluidic channel that is independent of the overlapping of microfeatures on different plates to establish the fluidic path for reagent loading. Initiated by a simple slipping step, the aqueous solution can robustly self-partition into individual droplets by capillary pressure-driven flow. This advantage makes the sp-SlipChip very appealing for the point-of-care quantitative analysis of viral load. As a proof of concept, we performed digital LAMP on an sp-SlipChip to quantify human papillomaviruses (HPVs) 16 and 18 and tested this method with fifteen anonymous clinical samples

Multiplex Digital Polymerase Chain Reaction on a Droplet Array SlipChip for Analysis of <i>KRAS</i> Mutations in Pancreatic Cancer

Pancreatic cancer is a terminal disease with high mortality and very poor prognosis. A sensitive and quantitative analysis of KRAS mutations in pancreatic cancer provides a tool not only to understand the biological mechanisms of pancreatic cancer but also for diagnosis and treatment monitoring. Digital polymerase chain reaction (PCR) is a promising tool for KRAS mutation analysis, but current methods generally require a complex microfluidic handling system, which can be challenging to implement in routine research and point-of-care clinical diagnostics. Here, we present a droplet-array SlipChip (da-SlipChip) for the multiplex quantification of KRAS G12D, V, R, and C mutant genes with the wild-type (WT) gene background by dual color (FAM/ROX) fluorescence detection. This da-SlipChip is a high-density microwell array of 21,696 wells of 200 pL in 4 by 5424 microwell format with simple loading and slipping operation. It does not require the same precise alignment of microfeatures on the different plates that are acquired by the traditional digital PCR SlipChip. This device can provide accurate quantification of both mutant genes and the WT KRAS gene. We collected tumor tissue, paired normal pancreatic tissue, and other normal tissues from 18 pancreatic cancer patients and analyzed the mutation profiles of KRAS G12D, V, R, and C in these samples; the results from the multiplex digital PCR on da-SlipChip agree well with those of next-generation sequencing (NGS). This da-SlipChip moves digital PCR closer to the practical point-of-care applications not only for detecting KRAS mutations in pancreatic cancer but also for other applications that require precise nucleic acid quantification with high sensitivity

Morbidity and maternal and infant outcomes of hypertensive disorder in pregnancy in China in 2018

Abstract Hypertensive disorder in pregnancy is a disease that occurs during pregnancy. We aimed to analyze the morbidity and maternal and infant outcomes with respect to the hypertensive disorder in pregnancy in China in 2018. Clinical data of 38 590 cases from 161 hospitals were retrospectively collected. The differences in morbidity and maternal and infant mortality among the major regions and provinces were compared. The overall national average morbidity was 4.74%, and the ratios of gestational hypertension, preeclampsia, eclampsia, chronic hypertension, and chronic hypertension with superimposed preeclampsia were 29.17%, 55.02%, 0.66%, 6.53%, and 8.62%, respectively. The overall maternal mortality was 0.61/100 000, and the case fatality was 0.13%. Morbidity associated with hypertensive disorder in pregnancy was 7.74% in North China, 6.62% in Northwest China, 6.40% in Central China, 5.83% in Northeast China, 4.28% in East China, 3.85% in South China, and 2.88% in Southwest China. The morbidity in each province was 1.62‐11.28%. The overall perinatal mortality was 3.59% (81.09% for stillbirths; 18.91% for neonatal deaths). Perinatal mortality decreased with increasing gestational weeks from 24 to 37 + 6 weeks. Perinatal mortality for delivery at 32 weeks of gestation in all regions of the country was <10%. Morbidity varied across regions in China, with the lowest in Southwest and the highest in North China. The low maternal mortality is related to the large‐scale development of standardized maternal health care in China. For severe hypertensive disorder patients, gestation should be prolonged to 32 weeks as often as possible for better neonatal survival rates