Smartphone-Based Droplet Digital LAMP Device with Rapid Nucleic Acid Isolation for Highly Sensitive Point-of-Care Detection

Abstract

While advances in microfluidics have enabled rapid and highly integrated detection of nucleic acid targets, the detection sensitivity is still unsatisfactory in the current POC (point-of-care) detection systems, especially for low abundance samples. In this study, a chip that integrates rapid nucleic acid extraction based on IFAST (immiscible phase filtration assisted by surface tension) and digital isothermal detection was developed to achieve highly sensitive POC detection within 60 min. Based on the interface theory, the factors influencing the interface stability of the IFAST process were studied, and the IFAST nucleic acid extraction conditions were optimized to increase the nucleic acid extraction recovery rate to 75%. Spiral mixing channel and flow-focusing droplet generation structure were designed to achieve the mixing and sample partitioning by applying negative pressure. A portable microdroplet fluorescence detection device was developed based on smartphone imaging. Validation tests were carried out for quantification of low-abundance cfDNA and detection of mutations.

A novel genomic model for predicting the likelihood of delayed graft function in DCD kidney transplantation

“…Meanwhile, patients with lower DGF risk may benefit from a shorter intensive monitoring period, therefore resulting in shorter overall hospital stays and lower medical costs (32). However, it is worth noting that the timeliness of gene expression quantification is key to the utility of the genomic model in clinical practice, which relies on the further development of rapid nucleic acid quantification technology and the optimization of whole processes of gene detection, including specimen collection and preparation, nucleic acid quantification and results return (33). On the other hand, given the limited recipient-based interventions for DGF, a more objective, reliable, and accurate quality assessment of DCD kidney grafts before KT may have greater practical significance (26).…”

“…On the other hand, given the limited recipient-based interventions for DGF, a more objective, reliable, and accurate quality assessment of DCD kidney grafts before KT may have greater practical significance (26). Fortunately, the ongoing improvement of NMP and rapid nucleic acid quantification undoubtedly enhances the feasibility and prospects of the genomic model in clinical practice for DGF prediction prior to DCD KT (17,33). The accurate risk stratification of DGF before transplantation based on the genomic model may not only guide comprehensive quality evaluation of DCD kidneys, reasonable allocation or discard of DCD kidneys and recipient-based preventive interventions (such as induction therapy by anti-thymocyte globulin), but also contribute to the speedy development of extracorporeal targeted therapies for DCD kidneys in the context of NMP, therefore preventing or minimizing the impact of DGF and effectively expanding the donor pool.…”

A Digital CRISPR-based Method for the Rapid Detection and Absolute Quantification of Viral Nucleic Acids

“…Additionally, the isothermal feature of our digital CRISPRbased detection assay confers faster amplification of the viral target using a simple constant-temperature heat bath, enabling rapid viral detection that can be deployed even in low-resource areas. In recent years, other digital isothermal methods, such as RPA-or LAMP-based digital PCR methods, have been developed for detecting a variety of DNA targets [49][50][51][52] . However, these methods are limited by their low specificity, due to the inherent tolerance of RPA/LAMP-based methods for base-pair mismatches as compared to traditional PCR methods [53][54][55][56][57][58] .…”

A Cross-Disciplinary View of Testing and Bioinformatic Analysis of SARS-CoV-2 and Other Human Respiratory Viruses in Pandemic Settings

“…Of note, the amount of DNA produced in LAMP reactions is higher than many conventional PCR reactions and the results can be visible to the naked eye [36][37][38]. The detection sensitivity is improved by a customized chip to integrate rapid nucleic acid extraction based on an immiscible phase filtration method assisted by surface tension and digital isothermal amplification [39].…”