Microfluidic electrical cell lysis for high-throughput and continuous production of cell-free varicella-zoster virus

Rapid Cryptococcus electroporated-lysis and sensitive detection on a miniaturized platform

Fast and accurate detection of Cryptococcus and precise differentiation of its subtypes is of great significance in protecting people from cryptococcal disease and preventing its spread in populations. However, traditional Cryptococcus identification and detection techniques still face significant challenges in achieving high analysis speed as well as high sensitivity. In this work, we report an electric microfluidic biochip. Compared to conventional methods that take several hours or even a day, this chip can detect Cryptococcus within 20 min, and achieve its maximum detection limit within 1 h, with the ability to differentiate between the Cryptococcus neoformans (NEO) and rare Cryptococcus gattii (GAT) efficiently, which accounts for nearly 100%. This device integrated two functional zones of an electroporation lysis (EL) zone for rapid cell lysis (<30 s) and an electrochemical detection (ED) zone for sensitive analysis of the released nucleic acids. The EL zone adopted a design of microelectrode arrays, which obtains a large electric field intensity at the constriction of the microchannel, addressing the safety concerns associated with high-voltage lysis. The device enables a limit of detection (LOD) of 60 pg/mL for NEO and 100 pg/mL for GAT through the modification of nanocomposites and specific probes. In terms of the detection time and sensitivity, the integrated microfluidic biochip demonstrates broad potential in Cryptococcus diagnosis and disease prevention.

Microfluidic-based technologies for diagnosis, prevention, and treatment of COVID-19: recent advances and future directions

The COVID-19 pandemic has posed significant challenges to existing healthcare systems around the world. The urgent need for the development of diagnostic and therapeutic strategies for COVID-19 has boomed the demand for new technologies that can improve current healthcare approaches, moving towards more advanced, digitalized, personalized, and patient-oriented systems. Microfluidic-based technologies involve the miniaturization of large-scale devices and laboratory-based procedures, enabling complex chemical and biological operations that are conventionally performed at the macro-scale to be carried out on the microscale or less. The advantages microfluidic systems offer such as rapid, low-cost, accurate, and on-site solutions make these tools extremely useful and effective in the fight against COVID-19. In particular, microfluidic-assisted systems are of great interest in different COVID-19-related domains, varying from direct and indirect detection of COVID-19 infections to drug and vaccine discovery and their targeted delivery. Here, we review recent advances in the use of microfluidic platforms to diagnose, treat or prevent COVID-19. We start by summarizing recent microfluidic-based diagnostic solutions applicable to COVID-19. We then highlight the key roles microfluidics play in developing COVID-19 vaccines and testing how vaccine candidates perform, with a focus on RNA-delivery technologies and nano-carriers. Next, microfluidic-based efforts devoted to assessing the efficacy of potential COVID-19 drugs, either repurposed or new, and their targeted delivery to infected sites are summarized. We conclude by providing future perspectives and research directions that are critical to effectively prevent or respond to future pandemics.

A simple transwell-based infection system for obtaining pure populations of VZV-infected cells

Varicella-Zoster virus (VZV) is a human herpesvirus and causes chickenpox and shingles. Research into its molecular virology has been hampered by a lack of methods for generation of high-titre, cell-free infectious virus preparations. VZV propagation and infection in vitro are therefore commonly achieved by co-culture of uninfected 'target' cells with infected 'inoculum' cells. A major drawback of this approach is that it results in mixed cell populations after infection. To overcome this limitation we developed a transwell-based VZV infection system. Infected inoculum cells and uninfected target cells are spatially separated by a transwell membrane. While cell-cell contact and VZV spread can occur through membrane pores, the two cell populations do not mix. This simple protocol requires no special instrumentation or reagents. We successfully used this system for infection of a range of target cells and obtained pure populations for downstream analyses such as flow cytometry and RT-qPCR. In sum, we developed a broadly applicable approach to study the molecular and cellular biology as well as host-pathogen interactions of VZV.

Bonding Strategies for Thermoplastics Applicable for Bioanalysis and Diagnostics

Microfluidics is a multidisciplinary science that includes physics, chemistry, engineering, and biotechnology. Such microscale systems are receiving growing interest in applications such as analysis, diagnostics, and biomedical research. Thermoplastic polymers have emerged as one of the most attractive materials for microfluidic device fabrication owing to advantages such as being optically transparent, biocompatible, cost-effective, and mass producible. However, thermoplastic bonding is a key challenge for sealing microfluidic devices. Given the wide range of bonding methods, the appropriate bonding approach should be carefully selected depending on the thermoplastic material and functional requirements. In this review, we aim to provide a comprehensive overview of thermoplastic fabricating and bonding approaches, presenting their advantages and disadvantages, to assist in finding suitable microfluidic device bonding methods. In addition, we highlight current applications of thermoplastic microfluidics to analyses and diagnostics and introduce future perspectives on thermoplastic bonding strategies.

Recent Advances in Microscale Electroporation

Electroporation (EP) is a commonly used strategy to increase cell permeability for intracellular cargo delivery or irreversible cell membrane disruption using electric fields. In recent years, EP performance has been improved by shrinking electrodes and device structures to the microscale. Integration with microfluidics has led to the design of devices performing static EP, where cells are fixed in a defined region, or continuous EP, where cells constantly pass through the device. Each device type performs superior to conventional, macroscale EP devices while providing additional advantages in precision manipulation (static EP) and increased throughput (continuous EP). Microscale EP is gentle on cells and has enabled more sensitive assaying of cells with novel applications. In this Review, we present the physical principles of microscale EP devices and examine design trends in recent years. In addition, we discuss the use of reversible and irreversible EP in the development of therapeutics and analysis of intracellular contents, among other noteworthy applications. This Review aims to inform and encourage scientists and engineers to expand the use of efficient and versatile microscale EP technologies.

Investigating host-virus interaction mechanism and phylogenetic analysis of viral proteins involved in the pathogenesis

Since the emergence of yellow fever in the Americas and the devastating 1918 influenza pandemic, biologists and clinicians have been drawn to human infecting viruses to understand their mechanisms of infection better and develop effective therapeutics against them. However, the complex molecular and cellular processes that these viruses use to infect and multiply in human cells have been a source of great concern for the scientific community since the discovery of the first human infecting virus. Viral disease outbreaks, such as the recent COVID-19 pandemic caused by a novel coronavirus, have claimed millions of lives and caused significant economic damage worldwide. In this study, we investigated the mechanisms of host-virus interaction and the molecular machinery involved in the pathogenesis of some common human viruses. We also performed a phylogenetic analysis of viral proteins involved in host-virus interaction to understand the changes in the sequence organization of these proteins during evolution for various strains of viruses to gain insights into the viral origin's evolutionary perspectives.