Microfluidic enrichment of bacteria coupled to contact-free lysis on a magnetic polymer surface for downstream molecular detection

Magnetic nanoparticles fabricated/integrated with microfluidics for biological applications: A review

Nanostructured materials have gained significant attention in recent years for their potential in biological applications, such as cell and biomolecular sorting, as well as early detection of metastatic cancer. Among these materials, magnetic nanoparticles (MNPs) stand out for their easy functionalization, high specific surface area, chemical stability, and superparamagnetic properties. However, conventional fabrication methods can lead to inconsistencies in MNPs' characteristics and performance, highlighting the need for a cost-effective, controllable, and reproducible synthesis approach. In this review, we will discuss the utilization of microfluidic technology as a cutting-edge strategy for the continuous and regulated synthesis of MNPs. This approach has proven effective in producing MNPs with a superior biomedical performance by offering precise control over particle size, shape, and surface properties. We will examine the latest research findings on developing and integrating MNPs synthesized through continuous microfluidic processes for a wide range of biological applications. By providing an overview of the current state of the field, this review aims to showcase the advantages of microfluidics in the fabrication and integration of MNPs, emphasizing their potential to revolutionize diagnostic and therapeutic methods within the realm of biotechnology.

Advances in the use of nanomaterials for nucleic acid detection in point-of-care testing devices: A review

The outbreak of the coronavirus (COVID-19) has heightened awareness of the importance of quick and easy testing. The convenience, speed, and timely results from point-of-care testing (POCT) in all vitro diagnostic devices has drawn the strong interest of researchers. However, there are still many challenges in the development of POCT devices, such as the pretreatment of samples, detection sensitivity, specificity, and so on. It is anticipated that the unique properties of nanomaterials, e.g., their magnetic, optical, thermal, and electrically conductive features, will address the deficiencies that currently exist in POCT devices. In this review, we mainly analyze the work processes of POCT devices, especially in nucleic acid detection, and summarize how novel nanomaterials used in various aspects of POCT products can improve performance, with the ultimate aims of offering new ideas for the application of nanomaterials and the overall development of POCT devices.

Technique Evolutions for Microorganism Detection in Complex Samples: A Review

Rapid detection of microorganisms is a major challenge in the medical and industrial sectors. In a pharmaceutical laboratory, contamination of medical products may lead to severe health risks for patients, such as sepsis. In the specific case of advanced therapy medicinal products, contamination must be detected as early as possible to avoid late production stop and unnecessary costs. Unfortunately, the conventional methods used to detect microorganisms are based on time-consuming and labor-intensive approaches. Therefore, it is important to find new tools to detect microorganisms in a shorter time frame. This review sums up the current methods and represents the evolution in techniques for microorganism detection. First, there is a focus on promising ligands, such as aptamers and antimicrobial peptides, cheaper to produce and with a broader spectrum of detection. Then, we describe methods achieving low limits of detection, thanks to Raman spectroscopy or precise handling of samples through microfluids devices. The last part is dedicated to techniques in real-time, such as surface plasmon resonance, preventing the risk of contamination. Detection of pathogens in complex biological fluids remains a scientific challenge, and this review points toward important areas for future research.

Multifunctional magnetic nanoparticle cloud assemblies for in situ capture of bacteria and isolation of microbial DNA

We investigate the formation of suspended magnetic nanoparticle (MNP) assemblies (M-clouds) and their use for in situ bacterial capture and DNA extraction. M-clouds are obtained as a result of magnetic field density variations when magnetizing an array of micropillars coated with a soft ferromagnetic NiP layer. Numerical simulations suggest that the gradient in the magnetic field created by the pillars is four orders of magnitude higher than the gradient generated by the external magnets. The pillars therefore serve as the sole magnetic capture sites for MNPs which accumulate on opposite sides of each pillar facing the magnets. Composed of loosely aggregated MNPs, the M-cloud can serve as a porous capture matrix for target analyte flowing through the array. The concept is demonstrated by using a multifunctional M-cloud comprising immunomagnetic NPs (iMNPs) for capture of Escherichia coli O157:H7 from river water along with silica-coated NPs for subsequent isolation and purification of microbial DNA released upon bacterial lysis. Confocal microscopy imaging of fluorescently labeled iMNPs and E. coli O157:H7 reveals that bacteria are trapped in the M-cloud region between micropillars. Quantitative assessment of in situ bacterial capture, lysis and DNA isolation using real-time polymerase chain reaction shows linear correlation between DNA output and input bacteria concentration, making it possible to confirm E. coli 0157:H7 at 10³ cells per mL. The M-cloud method further provides one order of magnitude higher DNA output concentrations than incubation of the sample with iMNPs in a tube for an equivalent period of time (e.g., 10 min). Results from assays performed in the presence of Listeria monocytogenes (at 10⁶ cells per mL each) suggest that non-target organisms do not affect on-chip E. coli capture, DNA extraction efficiency and quality of the eluted sample.

Leapfrogging laboratories: the promise and pitfalls of high-tech solutions for antimicrobial resistance surveillance in low-income settings

The scope and trajectory of today’s escalating antimicrobial resistance (AMR) crisis is inadequately captured by existing surveillance systems, particularly those of lower income settings. AMR surveillance systems typically collate data from routine culture and susceptibility testing performed in diagnostic bacteriology laboratories to support healthcare. Limited access to high quality culture and susceptibility testing results in the dearth of AMR surveillance data, typical of many parts of the world where the infectious disease burden and antimicrobial need are high. Culture and susceptibility testing by traditional techniques is also slow, which limits its value in infection management. Here, we outline hurdles to effective resistance surveillance in many low-income settings and encourage an open attitude towards new and evolving technologies that, if adopted, could close resistance surveillance gaps. Emerging advancements in point-of-care testing, laboratory detection of resistance through or without culture, and in data handling, have the potential to generate resistance data from previously unrepresented locales while simultaneously supporting healthcare. Among them are microfluidic, nucleic acid amplification technology and next-generation sequencing approaches. Other low tech or as yet unidentified innovations could also rapidly accelerate AMR surveillance. Parallel advances in data handling further promise to significantly improve AMR surveillance, and new frameworks that can capture, collate and use alternate data formats may need to be developed. We outline the promise and limitations of such technologies, their potential to leapfrog surveillance over currently available, conventional technologies in use today and early steps that health systems could take towards preparing to adopt them.

Review of Microfluidic Methods for Cellular Lysis

Cell lysis is a process in which the outer cell membrane is broken to release intracellular constituents in a way that important information about the DNA or RNA of an organism can be obtained. This article is a thorough review of reported methods for the achievement of effective cellular boundaries disintegration, together with their technological peculiarities and instrumental requirements. The different approaches are summarized in six categories: chemical, mechanical, electrical methods, thermal, laser, and other lysis methods. Based on the results derived from each of the investigated reports, we outline the advantages and disadvantages of those techniques. Although the choice of a suitable method is highly dependent on the particular requirements of the specific scientific problem, we conclude with a concise table where the benefits of every approach are compared, based on criteria such as cost, efficiency, and difficulty.

Scalable COVID-19 Detection Enabled by Lab-on-Chip Biosensors

Introduction

The emergence of a novel coronavirus, SARS-CoV-2, has highlighted the need for rapid, accurate, and point-of-care diagnostic testing. As of now, there is not enough testing capacity in the world to meet the stated testing targets, which are expected to skyrocket globally for broader testing during reopening

Aim

This review focuses on the development of lab-on-chip biosensing platforms for diagnosis of COVID-19 infection.

Results

We discuss advantages of utilizing lab-on-chip technologies in response to the current global pandemic, including their potential for low-cost, rapid sample-to-answer processing times, and ease of integration into a range of healthcare settings. We then highlight the development of magnetic, colorimetric, plasmonic, electrical, and lateral flow-based lab-on-chip technologies for the detection of SARS-CoV-2, in addition to other viruses. We focus on rapid, point-of-care technologies that can be deployed at scale, as such devices could be promising alternatives to the current gold standard of reverse transcription-polymerase chain reaction (RT-PCR) diagnostic testing.

Conclusion

This review is intended to provide an overview of the current state-of-the-field and serve as a resource for innovative development of new lab-on-chip assays for COVID-19 detection.