Application of Droplet Digital PCR Technology in Muscular Dystrophies Research

Comparative genetic diagnostic evaluation of pediatric neuromuscular diseases in a consanguineous population

Neuromuscular diseases (NMD) are a group of neurological diseases that manifest with various clinical symptoms affecting different components of the peripheral nervous system, which play a role in voluntary body movements control. The primary objective of this study is to explore the diagnostic efficacy of a combined genetic and biochemical testing approach for patients with neuromuscular diseases with diverse presentations in a population with high rate of consanguinity. Genetic testing was performed using selected Next Generation Sequencing (NGS) gene panels and whole exome sequencing on the peripheral blood sample from the patients. The study results revealed that the majority of patients in our cohort had a history of consanguinity (83%). Genetic testing through gene panels and Whole Exome Sequencing yielded similar result. Out of the patients tested, 66% underwent gene panels testing, 56% had Whole Exome Sequencing, 32% received array Comparative Genomic Hybridization (CGH) assays, and 40% underwent metabolic testing. Overall, 58 patients (61%) received definitive results after following all tests. Among the remaining 36 patients, 19 exhibited variants of unknown significance (VOUS) (21%).

Transformation gap from research findings to large-scale commercialized products in microfluidic field

The field of microfluidics has experienced rapid growth in the last several decades, yet it isn't considered to be a large industry comparable to semiconductor and consumer electronics. In this review, we analyzed the entire process of the transformation from research findings to commercialized products in microfluidics, as well as the significant gap during the whole developing process between microchip fabrication in R&D and large-scale production in the industry. We elaborated in detail on various materials in the microfluidics industry, including silicon, glass, PDMS, and thermoplastics, discussing their characteristics, production processes, and existing products. Despite challenges hindering the large-scale commercialization of microfluidic chips, ongoing advancements and applications are expected to integrate microfluidic technology into everyday life, transforming it into a commercially viable field with substantial potential and promising prospects.

An Integrated Micro-Heating System for On-Chip Isothermal Amplification of African Swine Fever Virus Genes

The loop-mediated isothermal amplification (LAMP) is widely used in the laboratory to facilitate rapid DNA or RNA detection with a streamlined operational process, whose properties are greatly dependent on the uniformity and rise rate of temperature in the reaction chambers and the design of the primers. This paper introduces a planar micro-heater equipped with an embedded micro-temperature sensor to realize temperature tunability at a low energy cost. Moreover, a control system, based on the Wheatstone bridge and proportional, integral, and derivative (PID) control, is designed to measure and adjust the temperature of the micro-heater. The maximum temperature rise rate of the designed micro-heater is ≈8 °C s-1, and it only takes ≈60 s to reach the target temperature. Furthermore, a designed plasmid, containing the B646L gene of African Swine Fever Virus (ASFV), and a set of specific primers, are used to combine with the designed micro-heating system to implement the LAMP reaction. Finally, the lateral flow assay is used to interpret the amplification results visually. This method can achieve highly sensitive and efficient detection of ASFV within 40 min. The sensitivity of this on-chip gene detection method is 8.4 copies per reaction, holding great potential for applications in DNA and RNA amplification.

Comparison of microbial molecular diagnosis efficiency within unstable template metagenomic DNA samples between qRT-PCR and chip-based digital PCR platforms

Accurate and efficient microbial diagnosis is crucial for effective molecular diagnostics, especially in the field of human healthcare. The gold standard equipment widely employed for detecting specific microorganisms in molecular diagnosis is quantitative real-time polymerase chain reaction (qRT-PCR). However, its limitations in low metagenomic DNA yield samples necessitate exploring alternative approaches. Digital PCR, by quantifying the number of copies of the target sequence, provides absolute quantification results for the bacterial strain. In this study, we compared the diagnostic efficiency of qRT-PCR and digital PCR in detecting a particular bacterial strain (Staphylococcus aureus), focusing on skin-derived DNA samples. Experimentally, specific primer for S. aureus were designed at transcription elongation factor (greA) gene and the target amplicon were cloned and sequenced to validate efficiency of specificity to the greA gene of S. aureus. To quantify the absolute amount of microorganisms present on the skin, the variable region 5 (V5) of the 16S rRNA gene was used, and primers for S. aureus identification were used to relative their amount in the subject's skin. The findings demonstrate the absolute convenience and efficiency of digital PCR in microbial diagnostics. We suggest that the high sensitivity and precise quantification provided by digital PCR could be a promising tool for detecting specific microorganisms, especially in skin-derived DNA samples with low metagenomic DNA yields, and that further research and implementation is needed to improve medical practice and diagnosis.

Laboratory testing for mitochondrial diseases: biomarkers for diagnosis and follow-up

The currently available biomarkers generally lack the specificity and sensitivity needed for the diagnosis and follow-up of patients with mitochondrial diseases (MDs). In this group of rare genetic disorders (mutations in approximately 350 genes associated with MDs), all clinical presentations, ages of disease onset and inheritance types are possible. Blood, urine, and cerebrospinal fluid surrogates are well-established biomarkers that are used in clinical practice to assess MD. One of the main challenges is validating specific and sensitive biomarkers for the diagnosis of disease and prediction of disease progression. Profiling of lactate, amino acids, organic acids, and acylcarnitine species is routinely conducted to assess MD patients. New biomarkers, including some proteins and circulating cell-free mitochondrial DNA, with increased diagnostic specificity have been identified in the last decade and have been proposed as potentially useful in the assessment of clinical outcomes. Despite these advances, even these new biomarkers are not sufficiently specific and sensitive to assess MD progression, and new biomarkers that indicate MD progression are urgently needed to monitor the success of novel therapeutic strategies. In this report, we review the mitochondrial biomarkers that are currently analyzed in clinical laboratories, new biomarkers, an overview of the most common laboratory diagnostic techniques, and future directions regarding targeted versus untargeted metabolomic and genomic approaches in the clinical laboratory setting. Brief descriptions of the current methodologies are also provided.