Detecting sepsis by observing neutrophil motility

Advancing cell-based therapy in sepsis: An anesthesia outlook

ABSTRACT

Sepsis poses a health challenge globally owing to markedly high rates of morbidity and mortality. Despite employing bundle therapy over two decades, approaches including transient organ supportive therapy and clinical trials focusing on signaling pathways have failed in effectively reversing multiple organ failure in patients with sepsis. Prompt and appropriate perioperative management for surgical patients with concurrent sepsis is urgent. Consequently, innovative therapies focusing on remedying organ injuries are necessitated. Cell therapy has emerged as a promising therapeutic avenue for repairing local damage to vital organs and restoring homeostasis during perioperative treatment for sepsis. Given the pivotal role of immune cell responses in the pathogenesis of sepsis, stem cell-based interventions that primarily modulate immune responses by interacting with multiple immune cells have progressed into clinical trials. The strides made in single-cell sequencing and gene-editing technologies have advanced the understanding of disease-specific immune responses in sepsis. Chimeric antigen receptor (CAR)-immune cell therapy offers an intriguing option for the treatment of sepsis. This review provides a concise overview of immune cell therapy, its current status, and the strides made in the context of sepsis research, discussing potential strategies for the management of patients with sepsis during perioperative stages.

Colorimetric Detection of Sepsis-Derived Hyperdegranulation with Plasmonic Nanosensors

Hyperdegranulation of neutrophilic granulocytes is a common finding in sepsis that directly contributes to the heightened immune response leading to organ dysfunction. Currently, cell degranulation is detected by flow cytometry, which requires large infrastructure that is not always available at the point of care. Here, we propose a plasmonic assay for detecting the degranulation status of septic cells colorimetrically. It is based on triggering the aggregation of gold nanoparticles with cationic granule proteins. Cells from septic patients contain fewer granules and therefore release less cationic proteins than healthy cells. This results in red-colored assays than can be easily detected by eye. The assay can selectively detect cationic granule proteins even in the presence of an excess of unrelated proteins, which is key to detect degranulation with high specificity. Coupling this signal generation mechanism with a magnetic purification step enabled the identification of septic cells with the same performance as flow cytometry. This makes the proposed method a promising alternative for diagnosing sepsis in decentralized healthcare schemes.

High resolution and rapid separation of bacteria from blood using elasto-inertial microfluidics

Improved sample preparation has the potential to address unmet needs for fast turnaround sepsis tests. In this work, we report elasto-inertial based rapid bacteria separation from diluted blood at high separation efficiency. In viscoelastic flows, we demonstrate novel findings where blood cells prepositioned at the outer wall entering a spiral device remain fully focused throughout the channel length while smaller bacteria migrate to the opposite wall. Initially, using microparticles, we show that particles above a certain size cut-off remain fully focused at the outer wall while smaller particles differentially migrate toward the inner wall. We demonstrate particle separation at 1 μm resolution at a total throughput of 1 mL/min. For blood-based experiments, a minimum of 1:2 dilution was necessary to fully focus blood cells at the outer wall. Finally, Escherichia coli spiked in diluted blood were continuously separated at a total flow rate of 1 mL/min, with efficiencies between 82 and 90% depending on the blood dilution. Using a single spiral, it takes 40 min to process 1 mL of blood at a separation efficiency of 82%. The label-free, passive, and rapid bacteria isolation method has a great potential for speeding up downstream phenotypic and genotypic analysis.

Point-of-critical-care diagnostics for sepsis enabled by multiplexed micro and nanosensing technologies

Sepsis is responsible for the highest economic and mortality burden in critical care settings around the world, prompting the World Health Organization in 2018 to designate it as a global health priority. Despite its high universal prevalence and mortality rate, a disproportionately low amount of sponsored research funding is directed toward diagnosis and treatment of sepsis, when early treatment has been shown to significantly improve survival. Additionally, current technologies and methods are inadequate to provide an accurate and timely diagnosis of septic patients in multiple clinical environments. For improved patient outcomes, a comprehensive immunological evaluation is critical which is comprised of both traditional testing and quantifying recently proposed biomarkers for sepsis. There is an urgent need to develop novel point-of-care, low-cost systems which can accurately stratify patients. These point-of-critical-care sensors should adopt a multiplexed approach utilizing multimodal sensing for heterogenous biomarker detection. For effective multiplexing, the sensors must satisfy criteria including rapid sample to result delivery, low sample volumes for clinical sample sparring, and reduced costs per test. A compendium of currently developed multiplexed micro and nano (M/N)-based diagnostic technologies for potential applications toward sepsis are presented. We have also explored the various biomarkers targeted for sepsis including immune cell morphology changes, circulating proteins, small molecules, and presence of infectious pathogens. An overview of different M/N detection mechanisms are also provided, along with recent advances in related nanotechnologies which have shown improved patient outcomes and perspectives on what future successful technologies may encompass. This article is categorized under: Diagnostic Tools > Biosensing.

Design of a Multiplexed Analyte Biosensor using Digital Barcoded Particles and Impedance Spectroscopy

Multiplexing allows quantifying multiple analytes in a single step, providing advantages over individual testing through shorter processing time, lower sample volume, and reduced cost per test. Currently, flow cytometry is the gold standard for biomedical multiplexing, but requires technical training, extensive data processing, and expensive operational and capital costs. To solve this challenge, we designed digital barcoded particles and a microfluidic architecture for multiplexed analyte quantification. In this work, we simulate and model non-fluorescence-based microfluidic impedance detection with a single excitation and detection scheme using barcoded polymer microparticles. Our barcoded particles can be designed with specific coding regions and generate numerous distinct patterns enabling digital barcoding. We found that signals based on adhered microsphere position and relative orientation were evaluated and separated based on their associated electrical signatures and had a 7 µm microsphere limit of detection. Our proposed microfluidic system can enumerate micron-sized spheres in a single assay using barcoded particles of various configurations. As representation of blood cells, the microsphere concentrations may provide useful information on disease onset and progression. Such sensors may be used for diagnostic and management of common critical care diseases like sepsis, acute kidney injury, urinary tract infections, and HIV/AIDS.