BCMA-Directed MRD Detection as a Predictor of Relapse after BCMA CAR T in Multiple Myeloma.

Background: Recent approvals of chimeric antigen receptor T-cells (CAR T) and bispecific antibody therapies offer new hope for relapsed refractory multiple myeloma (RRMM) patients, with superior efficacy over standard regimens observed in clinical trials. However, relapse after BCMA-directed therapy is common and requires further investigation.

Patients And Methods: We conducted a retrospective cohort study on 57 RRMM patients treated with BCMA-directed CAR T.

Novel thermoplastic microvalves based on an elastomeric cyclic olefin copolymer.

Microfluidic systems combine multiple processing steps and components to perform complex assays in an autonomous fashion. To enable the integration of several bio-analytical processing steps into a single system, valving is used as a component that directs fluids and controls introduction of sample and reagents. While elastomer polydimethylsiloxane has been the material of choice for valving, it does not scale well to accommodate disposable integrated systems where inexpensive and fast production is needed.

Microfluidic Isolation of Neuronal-Enriched Extracellular Vesicles Shows Distinct and Common Neurological Proteins in Long COVID, HIV Infection and Alzheimer's Disease.

Long COVID (LongC) is associated with a myriad of symptoms including cognitive impairment. We reported at the beginning of the COVID-19 pandemic that neuronal-enriched or L1CAM+ extracellular vesicles (nEVs) from people with LongC contained proteins associated with Alzheimer's disease (AD). Since that time, a subset of people with prior COVID infection continue to report neurological problems more than three months after infection.

In-plane Extended Nano-coulter Counter (XnCC) for the Label-free Electrical Detection of Biological Particles.

We report an in-plane extended nanopore Coulter counter (XnCC) chip fabricated in a thermoplastic via imprinting. The fabrication of the sensor utilized both photolithography and focused ion beam milling to make the microfluidic network and the in-plane pore sensor, respectively, in Si from which UV resin stamps were generated followed by thermal imprinting to produce the final device in the appropriate plastic (cyclic olefin polymer, COP). As an example of the utility of this in-plane extended nanopore sensor, we enumerated SARS-CoV-2 viral particles (VPs) affinity-selected from saliva and extracellular vesicles (EVs) affinity-selected from plasma samples secured from mouse models exposed to different ionizing radiation doses.

High Sensitivity Extended Nano-Coulter Counter for Detection of Viral Particles and Extracellular Vesicles.

We present a chip-based extended nano-Coulter counter (XnCC) that can detect nanoparticles affinity-selected from biological samples with low concentration limit-of-detection that surpasses existing resistive pulse sensors by 2-3 orders of magnitude. The XnCC was engineered to contain 5 in-plane pores each with an effective diameter of 350 nm placed in parallel and can provide high detection efficiency for single particles translocating both hydrodynamically and electrokinetically through these pores. The XnCC was fabricated in cyclic olefin polymer (COP) via nanoinjection molding to allow for high-scale production.

Assessing Breast Cancer Molecular Subtypes Using Extracellular Vesicles' mRNA.

Extracellular vesicles (EVs) carry RNA cargo that is believed to be associated with the cell-of-origin and thus have the potential to serve as a minimally invasive liquid biopsy marker for supplying molecular information to guide treatment decisions (i.e., precision medicine).

Nanofluidic devices for the separation of biomolecules.

Over the last 30-years, microchip electrophoresis and its applications have expanded due to the benefits it offers. Nanochip electrophoresis, on the other hand, is viewed as an evolving area of electrophoresis because it offers some unique advantages not associated with microchip electrophoresis. These advantages arise from unique phenomena that occur in the nanometer domain not readily apparent in the microscale domain due to scale-dependent effects.

Microfluidic affinity selection of active SARS-CoV-2 virus particles.

We report a microfluidic assay to select active severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral particles (VPs), which were defined as intact particles with an accessible angiotensin-converting enzyme 2 receptor binding domain (RBD) on the spike (S) protein, from clinical samples. Affinity selection of SARS-CoV-2 particles was carried out using injection molded microfluidic chips, which allow for high-scale production to accommodate large-scale screening. The microfluidic contained a surface-bound aptamer directed against the virus's S protein RBD to affinity select SARS-CoV-2 VPs.

System Modularity Chip for Analysis of Rare Targets (SMART-Chip): Liquid Biopsy Samples.

Liquid biopsies are becoming popular for managing a variety of diseases due to the minimally invasive nature of their acquisition, thus potentially providing better outcomes for patients. Circulating tumor cells (CTCs) are among the many different biomarkers secured from a liquid biopsy, and a number of efficient platforms for their isolation and enrichment from blood have been reported. However, many of these platforms require manual sample handling, which can generate difficulties when translating CTC assays into the clinic due to potential sample loss, contamination, and the need for highly specialized operators.

Affinity enrichment of extracellular vesicles from plasma reveals mRNA changes associated with acute ischemic stroke.

Currently there is no in vitro diagnostic test for acute ischemic stroke (AIS), yet rapid diagnosis is crucial for effective thrombolytic treatment. We previously demonstrated the utility of CD8(+) T-cells' mRNA expression for AIS detection; however extracellular vesicles (EVs) were not evaluated as a source of mRNA for AIS testing. We now report a microfluidic device for the rapid and efficient affinity-enrichment of CD8(+) EVs and subsequent EV's mRNA analysis using droplet digital PCR (ddPCR).

Liquid biopsy markers for stroke diagnosis.

Introduction: There is a short time window (4.5 h) for the effective treatment of acute ischemic stroke (AIS), which uses recombinant tissue plasminogen activator (rt-PA). Unfortunately, this short therapeutic timeframe is a contributing factor to the relatively small number of patients (~7%) that receive rt-PA.

Visible photorelease of liquid biopsy markers following microfluidic affinity-enrichment.

We detail a heterobifunctional, 7-aminocoumarin photocleavable (PC) linker with unique properties to covalently attach Abs to surfaces and subsequently release them with visible light (400-450 nm). The PC linker allowed rapid (2 min) and efficient (>90%) release of CTCs and EVs without damaging their molecular cargo.

Label-free counting of affinity-enriched circulating tumor cells (CTCs) using a thermoplastic micro-Coulter counter (μCC).

Coulter counters are used for counting particles and biological cells. Most Coulter counters are designed to analyze a sample without the ability to pre-process the sample prior to counting. For the analysis of rare cells, such as circulating tumor cells (CTCs), it is not uncommon to require enrichment before counting due to the modest throughput of μCCs and the high abundance of interfering cells, such as blood cells.

Microfluidic-based solid phase extraction of cell free DNA.

Cell-free DNA (cfDNA) is a liquid biopsy marker that can carry signatures (i.e., mutations) associated with certain pathological conditions.

Molecular Profiling of Liquid Biopsy Samples for Precision Medicine.

In the context of oncology, liquid biopsies consist of harvesting cancer biomarkers, such as circulating tumor cells, tumor-derived cell-free DNA, and extracellular vesicles, from bodily fluids. These biomarkers provide a source of clinically actionable molecular information that can enable precision medicine. Herein, we review technologies for the molecular profiling of liquid biopsy markers with special emphasis on the analysis of low abundant markers from mixed populations.

Isolation of circulating plasma cells from blood of patients diagnosed with clonal plasma cell disorders using cell selection microfluidics.

Blood samples from patients with plasma cell disorders were analysed for the presence of circulating plasma cells (CPCs) using a microfluidic device modified with monoclonal anti-CD138 antibodies. CPCs were immuno-phenotyped using a CD38/CD56/CD45 panel and identified in 78% of patients with monoclonal gammopathy of undetermined significance (MGUS), all patients with smouldering and symptomatic multiple myeloma (MM), and none in the controls. The burden of CPCs was higher in patients with symptomatic MM compared with MGUS and smouldering MM (p < 0.

Materials and microfluidics: enabling the efficient isolation and analysis of circulating tumour cells.

We present a critical review of microfluidic technologies and material effects on the analyses of circulating tumour cells (CTCs) selected from the peripheral blood of cancer patients. CTCs are a minimally invasive source of clinical information that can be used to prognose patient outcome, monitor minimal residual disease, assess tumour resistance to therapeutic agents, and potentially screen individuals for the early diagnosis of cancer. The performance of CTC isolation technologies depends on microfluidic architectures, the underlying principles of isolation, and the choice of materials.

Discrete microfluidics for the isolation of circulating tumor cell subpopulations targeting fibroblast activation protein alpha and epithelial cell adhesion molecule.

Circulating tumor cells consist of phenotypically distinct subpopulations that originate from the tumor microenvironment. We report a circulating tumor cell dual selection assay that uses discrete microfluidics to select circulating tumor cell subpopulations from a single blood sample; circulating tumor cells expressing the established marker epithelial cell adhesion molecule and a new marker, fibroblast activation protein alpha, were evaluated. Both circulating tumor cell subpopulations were detected in metastatic ovarian, colorectal, prostate, breast, and pancreatic cancer patients and 90% of the isolated circulating tumor cells did not co-express both antigens.

Microfluidics for the detection of minimal residual disease in acute myeloid leukemia patients using circulating leukemic cells selected from blood.

We report a highly sensitive microfluidic assay to detect minimal residual disease (MRD) in patients with acute myeloid leukemia (AML) that samples peripheral blood to search for circulating leukemic cells (CLCs). Antibodies immobilized within three separate microfluidic devices affinity-selected CLC subpopulations directly from peripheral blood without requiring pre-processing. The microfluidic devices targeted CD33, CD34, and CD117 cell surface antigens commonly expressed by AML leukemic cells so that each subpopulation's CLC numbers could be tracked to determine the onset of relapse.

Enzymatic cleavage of uracil-containing single-stranded DNA linkers for the efficient release of affinity-selected circulating tumor cells.

We report a novel strategy to enzymatically release affinity-selected cells, such as circulating tumor cells (CTCs), from surfaces with high efficiency (∼90%) while maintaining cell viability (>85%). The strategy utilizes single-stranded DNAs that link a capture antibody to the surfaces of a CTC selection device. The DNA linkers contain a uracil residue that can be cleaved.

Arrays of High-Aspect Ratio Microchannels for High-Throughput Isolation of Circulating Tumor Cells (CTCs).

Microsystem-based technologies are providing new opportunities in the area of in vitro diagnostics due to their ability to provide process automation enabling point-of-care operation. As an example, microsystems used for the isolation and analysis of circulating tumor cells (CTCs) from complex, heterogeneous samples in an automated fashion with improved recoveries and selectivity are providing new opportunities for this important biomarker. Unfortunately, many of the existing microfluidic systems lack the throughput capabilities and/or are too expensive to manufacture to warrant their widespread use in clinical testing scenarios.