Solid-phase extraction methods for nucleic acid separation. A review

Novel poly-deep eutectic solvent-functionalized magnetic graphene oxide nanomaterials for high-performance solid-phase extraction of trypsin

Three novel polymethacrylic acid-based deep eutectic solvent (DES)-functionalized magnetic graphene oxide composites were designed and successfully synthesized via the radical polymerization method. The aim was to achieve the selective solid-phase extraction of trypsin (Tryp). Among them, the magnetic extractant (MGO@PDES2) functionalized with a poly-deep eutectic solvent composed of tetraethylammonium chloride and methylpropionic acid at a molar ratio of 1 : 2 exhibited the highest extraction efficiency for Tryp. Owing to the high specific surface area of MGO and the abundant carboxyl functional groups in PDES2, the prepared MGO@PDES2 exhibited excellent selectivity and stability for Tryp extraction. Under optimal conditions, the extraction capacity of Tryp by MGO@PDES2 reached 708.85 mg g-1. The extraction driving forces between MGO@PDES2 and Tryp were hydrogen-bonding interactions and electrostatic interactions. Among the seven biomacromolecules, MGO@PDES2 displayed outstanding selectivity for Tryp. In addition, the results of cycling experiments indicated that MGO@PDES2 could be reused many times without a significant change in extraction capacity. Moreover, the proposed method was successfully applied to extract Tryp from the crude extract of bovine pancreas, yielding satisfactory results. All the results suggest that MGO@PDES2 is a promising magnetic extractant, which is expected to provide new ideas for the extraction and separation of proteins.

A Review on Optical Biosensors for Monitoring of Uric Acid and Blood Glucose Using Portable POCT Devices: Status, Challenges, and Future Horizons

The growing demand for real-time, non-invasive, and cost-effective health monitoring has driven significant advancements in portable point-of-care testing (POCT) devices. Among these, optical biosensors have emerged as promising tools for the detection of critical biomarkers such as uric acid (UA) and blood glucose. Different optical transduction methods, like fluorescence, surface plasmon resonance (SPR), and colorimetric approaches, are talked about, with a focus on how sensitive, specific, and portable they are. Despite considerable advancements, several challenges persist, including sensor stability, miniaturization, interference effects, and the need for calibration-free operation. This review also explores issues related to cost-effectiveness, data integration, and wireless connectivity for remote monitoring. The review further examines regulatory considerations and commercialization aspects of optical biosensors, addressing the gap between research developments and clinical implementation. Future perspectives emphasize the integration of artificial intelligence (AI) and healthcare for improved diagnostics, alongside the development of wearable and implantable biosensors for continuous monitoring. Innovative optical biosensors have the potential to change the way people manage their health by quickly and accurately measuring uric acid and glucose levels. This is especially true as the need for decentralized healthcare solutions grows. By critically evaluating existing work and exploring the limitations and opportunities in the field, this review will help guide the development of more efficient, accessible, and reliable POCT devices that can improve patient outcomes and quality of life.

Studying Cationic Liposomes for Quick, Simple, and Effective Nucleic Acid Preconcentration and Isolation

To ensure high quality of food and water, the identification of traces of pathogens is mandatory. Rapid nucleic acid-based tests shorten traditional detection times while maintaining low detection limits. Challenging is the loss of nucleic acids during necessary purification processes, since elution off solid surfaces is not efficient. We therefore propose the development of a vanishing surface strategy in which cationic liposomes efficiently capture nucleic acids. A lipoplex is formed that can be easily centrifuged down and washed if needed. Adding the lipoplex to detergent solutions or nucleic acid amplification reactions dissolves the liposomes, releasing 100% of the nucleic acid into the reaction. After initial protocol optimization, it was applied to isolate DNA from Escherichia coli, Staphylococcus aureus, and adenovirus in buffer followed by qPCR detection. This enabled the detection of these pathogens down to concentrations of 1 CFU or 1 PFU/mL, respectively. Comparing it to a standard commercial DNA extraction kit, it was superior, as evidenced by lower Ct-values in the qPCR for all pathogen concentrations. Scaling up to larger volumes, samples containing bacteria were first concentrated through nitrocellulose filters (pore size = 0.45 μm). Tap water, lake water, and rinse water of fresh produce were investigated, leading to relevant limits of detection of 100 CFU in 100 mL of tap water, 1000 CFU in 100 mL of lake water, and 100 CFU in 10 g of iceberg lettuce, respectively. Since the liposome protocol is a homogeneous, simple incubation step, it is a valuable alternative to standard commercial nucleic acid extraction kits.

Modular Microfluidic Sensor Integrating Nucleic Acid Extraction, CRISPR/Cas13a, and Electrochemiluminescence for Multichannel RNA Detection

Rapid and accurate screening of pathogens is crucial for disease detection. Here, a modular microfluidic sensor has been constructed for RNA detection, with integrated nucleic acid extraction, clustered regularly interspaced short palindromic repeats (CRISPR)/Cas13a reaction, and electrochemiluminescence (ECL) detection. The sensor consists of nucleic acid processing and detection modules. The nucleic acid processing module is used for nucleic acid extraction, RNA distribution, and the CRISPR/Cas reaction. Specifically, immiscible filtration assisted by surface tension is employed for nucleic acid extraction, significantly reducing the extraction time. Magnetic force is utilized for RNA distribution and transportation, minimizing the need for microstructures, such as microvalves and micropumps. Multichannel CRISPR/Cas13a reactions enable biological recognition, signal amplification, and multiplex detection. The fiber material-based detection module controls fluid flow and performs dry chemistry-based ECL detection. A novel multichannel closed bipolar electrode-based ECL (MCBPE-ECL) system is employed, with simplified experimental operations and enhanced sensitivity. Together, the multichannel CRISPR/Cas13a reactions and MCBPE-ECL enable the sensor's multiplexed detection. Under optimized conditions, the sensor can complete RNA extraction and detection in 30 min, with a detection limit of 0.372 fM for Escherichia coli 16S rRNA. Furthermore, in human blood samples, the detection limit for E. coli is 63.8 cfu/mL. Notably, the sensor can simultaneously determine the growth curves of single colonies of E. coli and Staphylococcus aureus strains in the same culture medium, demonstrating its multiplexed detection capability.

One-pot hydrothermal synthesis of polyethyleneimine-coated magnetic nanoparticles for high-efficient DNA extraction of pathogenic bacteria

For separation of deoxyribonucleic acid (DNA), positively charged amino-modified magnetic nanoparticles (MN) can effectively adsorb negatively charged DNA through electrostatic interaction. However, the reported preparation of amino-modified MN is usually tedious and time-consuming. Therefore, a simple synthesis method of amino-modified MN is necessary for DNA extraction. Herein, a novel polyethyleneimine-coated MN (PMN) was fabricated by one-pot hydrothermal synthesis for high-efficient DNA extraction. The fabricated PMN showed numerous exposed amino groups, which not only could effectively capture DNA through electrostatic interaction, but also limited the aggregation of PMN during application. Under optimized adsorption conditions, the maximum adsorption capacity of PMN for DNA could reach 192.4 μg m g-1. Shigella flexneri (S. flexneri) has the highest mortality rate among Shigella species and has been selected as target model pathogenic bacteria. Based on the optimized extraction conditions, PMN-based magnetic solid-phase microextraction (MSPE) and quantitative real-time PCR (qPCR) were integrated for detection of S. flexneri. The limit of detection of the proposed strategy was 2.4 × 102 CFU mL-1 and obviously lower than the commercial kit. To prove the practicability, the PMN-based MSPE combined qPCR strategy was successfully used in the determination of S. flexneri in spiked real sample, and the recovery values were in the range of 95.1 % to 102.1 % for apple juice, 60.4 % to 85.7 % for pickled vegetable, 97.8 % to 99.5 % for pig liver and 95.1 % to 102.1 % for pig colon, respectively. Therefore, we believe that the resultant PMN have great potential to become a universal magnetic adsorbent for high-efficient DNA extraction from complex biological samples.

Innovations in Transgene Integration Analysis: A Comprehensive Review of Enrichment and Sequencing Strategies in Biotechnology

Understanding the integration of transgene DNA (T-DNA) in transgenic crops, animals, and clinical applications is paramount for ensuring the stability and expression of inserted genes, which directly influence desired traits and therapeutic outcomes. Analyzing T-DNA integration patterns is essential for identifying potential unintended effects and evaluating the safety and environmental implications of genetically modified organisms (GMOs). This knowledge is crucial for regulatory compliance and fostering public trust in biotechnology by demonstrating transparency in genetic modifications. This review highlights recent advancements in T-DNA integration analysis, specifically focusing on targeted DNA enrichment and sequencing strategies. We examine key technologies, such as polymerase chain reaction (PCR)-based methods, hybridization capture, RNA/DNA-guided endonuclease-mediated enrichment, and high-throughput resequencing, emphasizing their contributions to enhancing precision and efficiency in transgene integration analysis. We discuss the principles, applications, and recent developments in these techniques, underscoring their critical role in advancing biotechnological products. Additionally, we address the existing challenges and future directions in the field, offering a comprehensive overview of how innovative DNA-targeted enrichment and sequencing strategies are reshaping biotechnology and genomics.

A novel nucleic acid extraction system integrating a switching valve-assisted microfluidic cartridge and a constant pressure pump

BACKGROUND

Nucleic acid extraction (NAE) is essential in molecular diagnostics, genetic engineering, and DNA sequencing. While advances in switching valve-assisted, self-contained microfluidic (S2M) cartridges have improved the NAE processes, challenges persist in streamlining workflows, reducing processing times, and enhancing multi-target detection. Achieving these objectives requires precise control of on-chip fluid dynamics and efficient transfer of nucleic acid solutions (NAS) to detection areas. However, research on novel S2M cartridge designs and compatible fluid control systems is still limited.

RESULT

This study presented an innovative NAE system that integrated an S2M cartridge, a constant pressure (CP) pump, a metal heating bath, a rotating lever, and a magnet. The S2M cartridge contained the reagents for both NAE and detection, while the CP pump provided stable, precise, and rapid fluid delivery, outperforming traditional peristaltic and injection pumps, especially for handling small volumes and reducing pulsation. A custom rotating lever connects reagent chambers, facilitating mixing, cleaning, elution, and NAS transfer. This system showed advantages over manual methods, achieving all processes in 20 min. The CP pump-assisted S2M cartridge enabled rapid MBs re-suspension with a recovery rate of 80 %. The system's sensitivity, repeatability, and ease of use were also confirmed. The NAE system can extract Escherichia coli DNA (50 CFU mL^-1) from food and serum samples and viral DNA (HBV, HCV, HIV) at 200 copies mL^-1 from serum samples.

SIGNIFICANCE

This study highlighted the need for an efficient fluid system in the S2M cartridge for stable NAE. By streamlining NAE and facilitating on-chip reagent preparation, the system enhanced point-of-care diagnostics. Although manual steps remain, the CP pump effectively managed fluid processes, paving the way for automated pathogen detection. Moreover, when combined with visual detection reagents, the NAE system showed promise as a direct molecular diagnostic tool.

Highly Sensitive Molecular Diagnostic Platform for Scrub Typhus Diagnosis Using O. tsutsugamushi Enrichment and Nucleic Acid Extraction

Scrub typhus is caused by the Gram-negative obligate intracellular bacterium Orientia tsutsugamushi, and this tick-borne disease is difficult to distinguish from other acute febrile illnesses as it typically presents with symptoms such as rash, crusting at the bite site, headache, myalgia, lymphadenopathy, and elevated liver transaminases. It can often be diagnosed clinically, but not all patients present with characteristic symptoms, so serological diagnosis and molecular techniques may be required. However, existing diagnostic tests often have low sensitivity and specificity, making early detection difficult. This study presents a nucleic acid extraction method using large volumes of plasma and buffy coat to increase sensitivity, as well as an improved detection method using two target genes. Using the I-PULL device, nucleic acids can be extracted from up to 4 mL of sample in 30 min, avoiding contamination. The extracted DNA detects two genes of O. tsutsugamushi, increasing sensitivity compared to single-gene detection. Clinical validation in 38 patient samples showed 100% specificity and 95.24% sensitivity for the single target gene, with specificity and sensitivity rising to 100% when both genes are analyzed. This molecular diagnostic platform can be useful for distinguishing scrub typhus from similar diseases.

Fabrication of micron-sized boronate-decorated polyethyleneimine-grafted magnetic agarose beads for specific enrichment of ribonucleic acid

Exploiting high-performance magnetic beads for specific enrichment of ribonucleic acid (RNA) has important significance in the biomedical research field. Herein, a simple strategy was proposed for fabricating boronate-decorated polyethyleneimine-grafted magnetic agarose beads (BPMAB), which can selectively isolate cis-diol-containing substances through boronate affinity. The size of the basic magnetic agarose beads was controlled through the emulsification of the water-in-oil emulsion with a high-speed shear machine, which enhanced the specific surface area of BPMAB. Subsequently, to modify more boronic acid ligands, branched PEI with excellent hydrophilicity and numerous reaction sites was grafted. 2,4-Difluoro-3-formylphenyl boronic acid (2,4-DFPBA) was covalently immobilized for selectively capturing cis-diol-containing substances under physiological condition (pH 7.4). The BPMAB with a diameter range from 1.86 μm to 11.60 μm possessed clearly spherical structure, and excellent magnetic responsiveness and suspension ability in aqueous solution. β-Nicotinamide adenine dinucleotide (β-NAD), a short-chain cis-diol carrying agent, was selected as a target molecule for evaluating the adsorption property of BPMAB and the maximum adsorption capacity of BPMAB for β-NAD could reach 205.11 mg g-1. In addition, the BPMAB as adsorbent was used to selectively enrich RNA from mammalian cells. The maximum adsorption capacity of BPMAB for RNA was 140.50 mg g-1. Under optimized conditions, the BPMAB-based MSPE successfully enriched the high-quality total RNA with 28S to 18S ribosomal RNA ratios ranging from 2.06 to 2.16. According to the PCR analysis of GADPH gene, the extracted total RNA was successfully reverse transcribed into cDNA. Therefore, we believe that the BPMAB-based MSPE could be applicable for the specific enrichment of RNA from complex biological systems.

Development and validation of a rapid five-minute nucleic acid extraction method for respiratory viruses

BACKGROUND

The rapid transmission and high pathogenicity of respiratory viruses significantly impact the health of both children and adults. Extracting and detecting their nucleic acid is crucial for disease prevention and treatment strategies. However, current extraction methods are laborious and time-consuming and show significant variations in nucleic acid content and purity among different kits, affecting detection sensitivity and efficiency. Our aim is to develop a novel method that reduces extraction time, simplifies operational steps, and ensures high-quality acquisition of respiratory viral nucleic acid.

METHODS

We extracted respiratory syncytial virus (RSV) nucleic acid using reagents with different components and analyzed cycle threshold (Ct) values via quantitative real-time polymerase chain reaction (qRT-PCR) to optimize and validate the novel lysis and washing solution. The performance of this method was compared against magnetic bead, spin column, and precipitation methods for extracting nucleic acid from various respiratory viruses. The clinical utility of this method was confirmed by comparing it to the standard magnetic bead method for extracting clinical specimens of influenza A virus (IAV).

RESULTS

The solution, composed of equal parts glycerin and ethanol (50% each), offers an innovative washing approach that achieved comparable efficacy to conventional methods in a single abbreviated cycle. When combined with our A Plus lysis solution, our novel five-minute nucleic acid extraction (FME) method for respiratory viruses yielded superior RNA concentrations and purity compared to traditional methods. FME, when used with a universal automatic nucleic acid extractor, demonstrated similar efficiency as various conventional methods in analyzing diverse concentrations of respiratory viruses. In detecting respiratory specimens from 525 patients suspected of IAV infection, the FME method showed an equivalent detection rate to the standard magnetic bead method, with a total coincidence rate of 95.43% and a kappa statistic of 0.901 (P < 0.001).

CONCLUSIONS

The FME developed in this study enables the rapid and efficient extraction of nucleic acid from respiratory samples, laying a crucial foundation for the implementation of expedited molecular diagnosis.

Optimization of Total DNA Extraction from Dried Blood Samples

While dried blood spots are a convenient source of genetic material, they are usually associated with a lower DNA yield than from a native sample. The study evaluated the DNA yield from dried blood samples prepared on glass fibre and cellulose membranes and investigated the reasons for the yield reduction. The extraction of total DNA from membrane-dried blood samples was optimized by spin-column extraction method. It was shown that preliminary short-term (20 min) solubilization of a dried matrix in an aqueous medium, followed by standard extraction protocols for the mixture of the eluate with membranes, provides the highest DNA yield. The yield of DNA from a glass fibre membrane was 40-50% lower compared to a native sample, but on average, two times higher than from a conventional cellulose membrane (filter paper). The reduction of DNA yield when using a dried sample was found to be due to partial retention of nucleic acids by the membrane material during the lysis stage.

The surface modification of the silica-coated magnetic nanoparticles and their application in molecular diagnostics of virus infection

The study presents a series of examples of magnetic nanoparticle systems designed for the diagnosis of viral diseases. In this interdisciplinary work, we describe one of the most comprehensive synthetic approaches for the preparation and functionalization of smart nanoparticle systems for rapid and effective RT-PCR diagnostics and isolation of viral RNA. Twelve different organic ligands and inorganic porous silica were used for surface functionalization of the Fe3O4 magnetic core to increase the number of active centres for efficient RNA binding from human swab samples. Different nanoparticle systems with common beads were characterized by HRTEM, SEM, FT-IR, XRD, XPS and magnetic measurements. We demonstrate the application of the fundamental models modified to fit the experimental zero-field cooling magnetization data. We discuss the influence of the nanoparticle shell parameters (morphology, thickness, ligands) on the overall magnetic performance of the systems. The prepared nanoparticles were tested for the isolation of viral RNA from tissue samples infected with hepatitis E virus-HEV and from biofluid samples of SARS-CoV-2 positive patients. The efficiency of RNA isolation was quantified by RT-qPCR method.

Biomonitoring urinary pesticide metabolites in preschool children by supported liquid extraction and ultra-high performance liquid chromatography-tandem mass spectrometry and their association with oxidative stress

Investigating pesticide exposure and oxidative stress in preschool children is essential for elucidating the determinants of environmental health in early life, with human biomonitoring of urinary pesticide metabolites serving as a critical strategy for achieving this objective. This study demonstrated biomonitoring of 2 phenoxyacetic acid herbicides, 2 organophosphorus pesticide metabolites, and 4 pyrethroid pesticide metabolites in 159 preschool children and evaluated their association with oxidative stress biomarker 8-hydroxydeoxyguanosine. An enzymatic deconjugation process was used to release urinary pesticide metabolites, which were then extracted and enriched by supported liquid extraction, and quantified by ultra-high performance liquid chromatography-tandem mass spectrometry with internal standard calibration. Dichloromethane: methyl tert‑butyl ether (1:1, v/v) was optimized as the solvent for supported liquid extraction, and we validated the method for linear range, recovery, matrix effect and method detection limit. Method detection limit of the pesticide metabolites ranged from 0.01 μg/L to 0.04 μg/L, with satisfactory recoveries ranging from 70.5 % to 95.5 %. 2,4,5-Trichlorophenoxyacetic acid was not detected, whereas the other seven pesticide metabolites were detected with frequencies ranging from 10.1 % to 100 %. The concentration of urinary pesticide metabolites did not significantly differ between boys and girls, with the median concentrations being 9.39 μg/L for boys and 4.90 μg/L for girls, respectively. Spearman correlation analysis indicated that significant positive correlations among urinary metabolites. Bayesian kernel machine regression revealed a significant positive association between urinary pesticide metabolites and 8-hydroxydeoxyguanosine. Para-nitrophenol was the pesticide metabolite that contributed significantly to the elevated level of oxidative stress.

A quadratic isothermal amplification fluorescent biosensor without intermediate purification for ultrasensitive detection of circulating tumor DNA

Circulating tumor DNA (ctDNA) is an auspicious tumor biomarker released into the bloodstream by tumor cells, offering abundant information concerning cancer genes. It plays a crucial role in the early diagnosis of cancer. However, due to extremely low levels in body fluids, achieving a simple, sensitive, and highly specific detection of ctDNA remains challenging. Here, we constructed a purification-free fluorescence biosensor based on quadratic amplification of ctDNA by combining nicking enzyme mediated amplification (NEMA) and catalytic hairpin assembly (CHA) reactions. After double isothermal amplification, this biosensor achieved an impressive signal amplification of nearly 107-fold, enabling it to detect ctDNA with ultra-sensitivity. And the detection limit of this biosensor is as low as 2 aM. In addition, we explored the influence of human serum on the performance of the biosensor and found that it showed favorable sensitivity in the presence of serum. This biosensor eliminates the need for an intermediate purification step, resulting in enhanced sensitivity and convenience. Thus, our purification-free fluorescent biosensor exhibits ultra-high sensitivity when compared to other biosensors and has the potential to serve as an effective diagnostic tool for early detection of cancer.

High-efficient separation of deoxyribonucleic acid from pathogenic bacteria by hedgehog-inspired magnetic nanoparticles microextraction

Efficient separation of deoxyribonucleic acid (DNA) through magnetic nanoparticles (MN) is a widely used biotechnology. Hedgehog-inspired MNs (HMN) possess a high-surface-area due to the distinct burr-like structure of hedgehog, but there is no report about the usage of HMN for DNA extraction. Herein, to improve the selection of MN and illustrate the performance of HMN for DNA separation, HMN and silica-coated Fe3O4 nanoparticles (Fe3O4@SiO2) were fabricated and compared for the high-efficient separation of pathogenic bacteria of DNA. Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) are typical Gram-negative and Gram-positive bacteria and are selected as model pathogenic bacteria. To enhance the extraction efficiency of two kinds of MNs, various parameters, including pretreatment, lysis, binding and elution conditions, have been optimized in detail. In most separation experiments, the DNA yield of HMN was higher than that of Fe3O4@SiO2. Therefore, a HMN-based magnetic solid-phase microextraction (MSPE) and quantitative real-time PCR (qPCR) were integrated and used to detect pathogenic bacteria in real samples. Interestingly, the HMN-based MSPE combined qPCR strategy exhibited high sensitivity with a limit of detection of 2.0 × 101 CFU mL-1 for E. coli and 4.0 × 101 CFU mL-1 for S. aureus in orange juice, and 2.8 × 102 CFU mL-1 for E. coli and 1.1 × 102 CFU mL-1 for S. aureus in milk, respectively. The performance of the proposed strategy was significantly better than that of commercial kit. This work could prove that the novel HMN could be applicable for the efficient separation of DNA from complex biological samples.

Numerical and experimental investigation on the performance of rapid ultrasonic-assisted nucleic acid extraction based on dispersive two-phase flow

BACKGROUND

Nucleic acid extraction (NAE) is an essential step in the whole process of nucleic acid detection (NAT). Traditional manual extraction methods are time-consuming and laborious, unfavorable to the point-of-care testing of nucleic acids. Ultrasound has been emphasized due to its noncontact and easy-to-manipulate characteristics, and integration with microfluidic chip can realize rapid NAE through acoustic streaming effect. The uniformity of magnetic bead mixing in this process is a critical factor affecting the extraction effect. In this study, we developed an ultrasound-assisted NAE technique based on the magnetic bead method and optimized the chip structure to achieve rapid NAE.

RESULT

We use ultrasonic-assisted coupled with magnetic bead method for ultra-fast NAE. The mixing process of magnetic beads driven by acoustic streaming is simulated by a dispersive two-phase flow model, and the ultrasonic incidence angle (θin), cone structure aspect ratio (Dc/Hc) and sheet structure thickness (Hp) are optimized to enhance the mixing performance. Furthermore, the effectiveness of NAE is validated by utilizing quantitative real-time PCR (qPCR) detection. The findings reveal that a θin value of 10° yields superior mixing performance compared to other incidence angles, resulting in a maximum increase of 84 % in mixing intensity. When Dc/Hc = 0.5 and Hp = 0.5 mm, the maximum mixing index in the localized region of the chamber after 1 s of ultrasound action can reach 83.6 % and 92.5 %, respectively. Compared to the original chamber, the CT values extracted after 5 s of ultrasound action shifted forward by up to 1.9 ct and 4.1 ct, respectively.

SIGNIFICANCE

The dispersed two-phase flow model can effectively simulate the mixing process of magnetic beads, which plays an important role in assisting the structural design of chip extraction chambers. The single-step mixing of ultrasound-assisted NAE takes only 15s to achieve an extraction performance comparable to manual extraction. The extraction process can be completed within 7 min after integrating this technology with microfluidic chips and automated equipment, providing a solution for automated and efficient NAE.

On-line extraction and determination of coumarins compounds from mouse plasma based on a homemade phenyl-hybrid monolithic adsorbent

A phenyl-hybrid monolithic adsorbent was prepared using an organic monomer of ethylene glycol phenyl ether acrylate and inorganic monomers of tetramethoxysilane and vinyltrimethoxysilane, via polycondensation and polymerization in a stainless-steel column, which shows porous structure and multiple functional groups, according to the measurements of scanning electron microscopy, nitrogen adsorption-desorption method and infrared spectroscopy. The resulting hybrid phenyl-based monolith was used as a solid-phase extraction column, combining with an analytical column in conjunction with high-performance liquid chromatography system for the on-line extraction and determination of coumarins (praeruptorin A and praeruptorin B) in Peucedani Radix from mouse plasma. The homemade hybrid monolithic solid-phase extraction column exhibits good removal ability for the sample matrices, as well as unique selectivity for the two praeruptorins. Methodology validation results indicate that the present method is applicable for the on-line extraction and quantitative analysis of praeruptorin A and praeruptorin B in Peucedani Radix from mouse plasma with a limit of quantitation 0.06 μg/mL and a linear range 0.06-5 μg/mL (r＞0.999), thus indicating the present method is a promising and alternative method for the quantitative determination of similar target components with micro or trace concentration from complex extract solution and plasma.

Abridged solid-phase extraction with alkaline Poly(ethylene) glycol lysis (ASAP) for direct DNA amplification

Complexity of sample preparation decelerate the development of sample-in-answer-out devices for point-of-need nucleic acid amplification testing. Here, we present the consolidation of alkaline poly(ethylene) glycol-based lysis and solid-phase extraction for rapid and simple sample preparation compatible with direct on-bead amplification. Simultaneous cell lysis and binding of DNA were achieved using an optimised reagent comprising 15% PEG8000, 0.5 M NaCl, and 3.5 mM KOH. This was combined with direct, on-bead amplification using 1.5 μg beads per 20 μL PCR reaction mix. The novel single reagent, 5-min method improved the detection limit by 10 and 100-fold compared with commercial DNA extraction kits and the original alkaline PEG lysis method, respectively. The sensitivity can be further enhanced by one amplification cycle with an ethanol wash or by extending the incubation to 10 min before collecting the magnetic particles. Both methods successfully detected a single copy of Escherichia coli DNA. In biological fluids (saliva, sweat, and urine), the 5-min method was delayed by about one cycle compared to the 15-min method. The proposed methods are attractive for incorporation in the workflow for point-of-need testing of biological samples by providing a practical and chemical method for simple alternative DNA sample preparation.

Integrated Three-Dimensional Microdevice with a Modified Surface for Enhanced DNA Separation from Biological Samples

Functional interfaces and devices for rapid adsorption and immobilization of nucleic acids (NAs) are significant for relevant bioengineering applications. Herein, a microdevice with poly(acrylic acid) (PAA) photosensitive resin was integrated by three-dimensional (3D) printing, named DPAA for short. Precise microscale structures and abundant surface carboxyl functional groups were fabricated for fast and high-throughput deoxyribonucleic acid (DNA) separation. Surface modification was then done using polydopamine (PDA) and poly(ethylene glycol) (PEG) to obtain modified poly(acrylic acid) (PAA)-based devices DPDA-PAA and DPEG-PAA rich in amino and hydroxyl groups, respectively. The fabricated device DPAA possessed superior printing accuracy (40-50 μm). Functionalization of amino and hydroxyl was successful, and the modified devices DPDA-PAA and DPEG-PAA maintained a high thermal stability like DPAA. Surface potential analysis and molecular dynamics simulation indicated that the affinity for DNA was in the order of DPDA-PAA > DPEG-PAA > DPAA. Further DNA separation experiments confirmed the high throughput and high selectivity of DNA separation performance, consistent with the predicted affinity results. DPDA-PAA showed relatively the highest DNA extraction yield, while DPEG-PAA was the worst. An acidic binding system is more favorable for DNA separation and recovery. DPDA-PAA showed significantly better DNA extraction performance than DPAA in a weakly acidic environment (pH 5.0-7.0), and the average DNA yield of the first elution was 2.16 times that of DPAA. This work validates the possibility of modification on integrated 3D microdevices to improve their DNA separation efficiency effectively. It also provides a new direction for the rational design and functionalization of bioengineering separators based on nonmagnetic methods. It may pave a new path for the highly efficient polymerase chain reaction diagnosis.

Early monitoring-to-warning Internet of Things system for emerging infectious diseases via networking of light-triggered point-of-care testing devices

Early monitoring and warning arrangements are effective ways to distinguish infectious agents and control the spread of epidemic diseases. Current testing technologies, which cannot achieve rapid detection in the field, have a risk of slowing down the response time to the disease. In addition, there is still no epidemic surveillance system, implementing prevention and control measures is slow and inefficient. Motivated by these clinical needs, a sample-to-answer genetic diagnosis platform based on light-controlled capillary modified with a photocleavable linker is first developed, which could perform nucleic acid separation and release by light irradiation in less than 30 seconds. Then, on site polymerase chain reaction was performed in a handheld closed-loop convective system. Test reports are available within 20 min. Because this method is portable, rapid, and easy to operate, it has great potential for point-of-care testing. Additionally, through multiple device networking, a real-time artificial intelligence monitoring system for pathogens was developed on a cloud server. Through data reception, analysis, and visualization, the system can send early warning signals for disease control and prevention. Thus, anti-epidemic measures can be implemented effectively, and deploying and running this system can improve the capabilities for the prevention and control of infectious diseases.

Point-of-Care Testing for Hepatitis Viruses: A Growing Need

Viral hepatitis, caused by hepatitis A virus (HAV), hepatitis B virus (HBV), hepatitis C virus (HCV), hepatitis D virus (HDV), or hepatitis E virus (HEV), is a major global public health problem. These viruses cause millions of infections each year, and chronic infections with HBV, HCV, or HDV can lead to severe liver complications; however, they are underdiagnosed. Achieving the World Health Organization's viral hepatitis elimination goals by 2030 will require access to simpler, faster, and less expensive diagnostics. The development and implementation of point-of-care (POC) testing methods that can be performed outside of a laboratory for the diagnosis of viral hepatitis infections is a promising approach to facilitate and expedite WHO's elimination targets. While a few markers of viral hepatitis are already available in POC formats, tests for additional markers or using novel technologies need to be developed and validated for clinical use. Potential methods and uses for the POC testing of antibodies, antigens, and nucleic acids that relate to the diagnosis, monitoring, or surveillance of viral hepatitis infections are discussed here. Unmet needs and areas where additional research is needed are also described.

Chemometric assisted natural DES based VA-DLLME-LC-MS/MS method for the quantitative determination of Garcinol in biofluids/tissues: A practical application to pharmacokinetics and biodistribution studies

Garcinol (GAR) is a polyisoprenylated benzophenone obtained from Garcinia indica used as anti-oxidant and anti-inflammatory in traditional medicine and due to these activities, it possesses anticancer properties. It is considered to be a next generation epigenetic drug. A green solvent based analytical method which is efficient, sophisticated, and highly enriched has been developed for the quantitative analysis of GAR in biological samples (plasma, liver, kidney and spleen) with the use of deep eutectic solvent (DES) for its extraction. A series of 23 DESs were synthesized and out of which, Thymol (Th)-Terpeniol (T), 2:1 molar ratio with a more hydrophobic environment and high interaction efficiency between GAR and DES was identified for the better extraction from mice plasma and tissue samples. The Design of Experiment approaches like placket-burmann design and central composite design were used to optimize the method conditions. The method validation characteristics, such as limit of detection (0.193-0.237 ng/mL), limit of quantification (0.644-0.697 ng/mL), lower limit of quantification (0.5 ng/mL), broad range of linearity with R2 (0.9994-0.9997) with a percent recovery not less than 87% was observed, which are well within the acceptance criteria for a bioanalytical method. The enrichment factor is upto 53-60 folds, with high extraction efficiency (89-97%). The measurement uncertainty was estimated with an expanded uncertainty ranged between 10.9%-19.0%. The method developed and validated was effectively applied to examine the pharmacokinetic and biodistribution patterns for GAR in mice.

Magnetic Janus origami robot for cross-scale droplet omni-manipulation

The versatile manipulation of cross-scale droplets is essential in many fields. Magnetic excitation is widely used for droplet manipulation due to its distinguishing merits. However, facile magnetic actuation strategies are still lacked to realize versatile multiscale droplet manipulation. Here, a type of magnetically actuated Janus origami robot is readily fabricated for versatile cross-scale droplet manipulation including three-dimensional transport, merging, splitting, dispensing and release of daughter droplets, stirring and remote heating. The robot allows untethered droplet manipulation from ~3.2 nL to ~51.14 μL. It enables splitting of droplet, precise dispensing (minimum of ~3.2 nL) and release (minimum of ~30.2 nL) of daughter droplets. The combination of magnetically controlled rotation and photothermal properties further endows the robot with the ability to stir and heat droplets remotely. Finally, the application of the robot in polymerase chain reaction (PCR) is explored. The extraction and purification of nucleic acids can be successfully achieved.

A dual paper-based nucleic acid extraction method from blood in under ten minutes for point-of-care diagnostics

Nucleic acid extraction (NAE) plays a crucial role for diagnostic testing procedures. For decades, dried blood spots (DBS) have been used for serology, drug monitoring, and molecular studies. However, extracting nucleic acids from DBS remains a significant challenge, especially when attempting to implement these applications to the point-of-care (POC). To address this issue, we have developed a paper-based NAE method using cellulose filter papers (DBSFP) that operates without the need for electricity (at room temperature). Our method allows for NAE in less than 7 min, and it involves grade 3 filter paper pre-treated with 8% (v/v) igepal surfactant, 1 min washing step with 1× PBS, and 5 min incubation at room temperature in 1× TE buffer. The performance of the methodology was assessed with loop-mediated isothermal amplification (LAMP), targeting the human reference gene beta-actin and the kelch 13 gene from P. falciparum. The developed method was evaluated against FTA cards and magnetic bead-based purification, using time-to-positive (min) for comparative analysis. Furthermore, we optimised our approach to take advantage of the dual functionality of the paper-based extraction, allowing for elution (eluted disk) as well as direct placement of the disk in the LAMP reaction (in situ disk). This flexibility extends to eukaryotic cells, bacterial cells, and viral particles. We successfully validated the method for RNA/DNA detection and demonstrated its compatibility with whole blood stored in anticoagulants. Additionally, we studied the compatibility of DBSFP with colorimetric and lateral flow detection, showcasing its potential for POC applications. Across various tested matrices, targets, and experimental conditions, our results were comparable to those obtained using gold standard methods, highlighting the versatility of our methodology. In summary, this manuscript presents a cost-effective solution for NAE from DBS, enabling molecular testing in virtually any POC setting. When combined with LAMP, our approach provides sample-to-result detection in under 35 minutes.

Rapid automatic nucleic acid purification system based on gas-liquid immiscible phase

The continuous expansion of nucleic acid detection applications has resulted in constant developments in rapid, low-consumption, and highly automated nucleic acid extraction methods. Nucleic acid extraction using magnetic beads across an immiscible phase interface offers significant simplification and parallelization potential. The gas-liquid immiscible phase valve eliminates the requirement for complicated cassettes and is suitable for automation applications. By analyzing the process of magnetic beads crossing the gas-liquid interface, we utilized a low magnetic field strength to drive large magnetic bead packages to cross the gas-liquid interface, providing a solution of high magnetic bead recovery rate for solid-phase extraction with a low-surfactant system based on gas-liquid immiscible phase valve. The recovery rate of magnetic beads was further improved to 90%-95% and the carryover of the reagents was below 1%. Consequently, a chip and an automatic system were developed to verify the applicability of this method for nucleic acid extraction. The Hepatitis B virus serum standard was used for the extraction test. The extraction of four samples was performed within 7 minutes, with nucleic acid recovery maintained above 80% and good purity. Thus, through analysis and experiments, a fast, highly automated, and low-consumption nucleic acid recovery method was proposed in this study.

Magnetic/Zeolitic Imidazolate Framework-67 Nanocomposite for Magnetic Solid-Phase Extraction of Five Flavonoid Components from Chinese Herb Dicranopteris pedata

A magnetically functionalized Fe₃O₄@ZIF-67 metal-organic framework (MOF) was prepared by electrostatic self-assembly using magnetic Fe₃O₄ nanoparticles as the core and ZIF-67 as the shell. The composite was characterized by electron microscopy, X-ray diffraction, Fourier- transform infrared spectroscopy, and Brunauer-Emmett-Teller measurements. Magnetic solid-phase extraction (MSPE) was performed on five flavonoids from Dicranopteris pedata using Fe₃O₄@ZIF-67 as an adsorbent. The developed MSPE method was combined with high-performance liquid chromatography-ultraviolet detection to preconcentrate and separate five flavonoids (rutin, quercitrin, kaempferol-3-O-α-L-rhamnoside, quercetin, and kaempferol) from Dicranopteris pedata. The factors affecting the extraction, such as the amount of Fe₃O₄@ZIF-67 adsorbent, salt ion concentration in the sample solution, vortex time, type and amount of desorbing solvent, concentration of formic acid to acidify the desorbing solvent, and acetonitrile ratio, were optimized. The developed method showed good linearity over the concentration range of 1.09-70.0 μg∙mL^-1 for the five flavonoids, with R² values between 0.9901 and 0.9945. The limits of detection and average recoveries for the five flavonoids were in the ranges of 39.5-56.2 ng∙mL^-1 and 92.2-100.7%, respectively. The method presented herein is simple, efficient, and sensitive; it can be used for enrichment analysis of the five flavonoids in Dicranopteris pedata.

Recent advancements in nucleic acid detection with microfluidic chip for molecular diagnostics

The coronavirus disease 2019 (COVID-19) has extensively promoted the application of nucleic acid testing technology in the field of clinical testing. The most widely used polymerase chain reaction (PCR)-based nucleic acid testing technology has problems such as complex operation, high requirements of personnel and laboratories, and contamination. The highly miniaturized microfluidic chip provides an essential tool for integrating the complex nucleic acid detection process. Various microfluidic chips have been developed for the rapid detection of nucleic acid, such as amplification-free microfluidics in combination with clustered regularly interspaced short palindromic repeats (CRISPR). In this review, we first summarized the routine process of nucleic acid testing, including sample processing and nucleic acid detection. Then the typical microfluidic chip technologies and new research advances are summarized. We also discuss the main problems of nucleic acid detection and the future developing trend of the microfluidic chip.

Integrating magnetic metal-organic frameworks-based sample preparation with microchannel resistance biosensor for rapid and quantitative detection of aflatoxin B1

Aflatoxin B₁, a secondary metabolite produced by fungi, is one of the most toxic mycotoxins that poses a major food security and public health threat worldwide. Effective sample pretreatment and high sensitivity detection techniques are urgently needed due to its trace amount in complex samples. Herein, an integrated detection strategy was developed by combining Mg/Zn-metal organic framework-74 modified Fe₃O₄ magnetic nanoparticles (Mg/Zn-MOF-74 @Fe₃O₄ MNPs)-based sample preparation and microchannel resistance biosensor for rapid and highly sensitive detection of aflatoxin B₁ in food samples. The synthesis and characterization of Mg/Zn-MOF-74 @Fe₃O₄ MNPs was reported, which exhibited efficient separation and enrichment capacity when exposed to complex grain samples. The competitive immunoassay-based microchannel resistance biosensor enabled specific and high-sensitive analysis of aflatoxin B₁ by using current as a readout, which caused by the blocking effect between the functionalized-polystyrene microspheres and microchannel. Under optimized conditions, this biosensor was capable to quantitatively analysis aflatoxin B₁ from 10 pg/mL to 20 ng/mL, and with a limit of detection of 4.75 pg/mL. This integrated detection strategy has been tested for the quantitative detection of aflatoxin B₁ in grain samples that is a potential protocol for food safety control and environmental monitoring.

Magnetic Nylon 6 Nanocomposites for the Microextraction of Nucleic Acids from Biological Samples

Magnetic Fe3O4 nanoparticles (MNPs) have great potential for nucleic acid separation, detection, and delivery. MNPs are considered a valuable tool in biomedicine due to their cost-effectiveness, stability, easy surface functionalization, and the possibility of the manipulations under a magnetic field. Herein, the synthesis of magnetic nylon 6 nanocomposites (MNPs@Ny6) was investigated. Transmission electron microscopy (TEM) was used for morphology and size analysis. A new method of UV-induced immobilization of oligonucleotides on MNPs@Ny6 for nucleic acid magnetic separation was proposed. MNPs@Ny6 shows a high oligonucleotide binding capacity of 2.2 nmol/mg with 73.3% loading efficiency. The proposed system has been applied to analyze model mixtures of target RNA on the total yeast RNA background. The RNA target isolation efficiency was 60% with high specificity. The bind RNA release was 88.8% in a quantity of 0.16 nmol/mg. The total RNA capture efficiency was 53%. Considering this, the MNPs@Ny6 is an attractive candidate for nucleic acids-specific magnetic isolation.

Integrated ultrasound-assisted magnetic solid-phase extraction for efficient determination and pre-concentration of polycyclic aromatic hydrocarbons from high-consumption soft drinks and non-alcoholic beers in Iran

In the present research, an ultrasound-assisted magnetic solid-phase extraction coupled with a gas chromatography-mass spectrometry hybrid system was developed for extraction/determination of trace amounts of polycyclic aromatic hydrocarbons in high-consumption soft drinks and non-alcoholic beers in Iran using magnetite graphene oxide adsorbent. The magnetite graphene oxide was characterized by scanning electron microscope, transmission electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, and vibrating-sample magnetometer techniques. The highest extraction recovery (73.05 to 95.56%) and enrichment factor (90.65 to 106.38) were obtained at adsorbent mass: 10 mg, adsorption time: 30 min, salt addition: sodium chloride 10% w/v, desorption time: 20 min, eluent type: hexane: acetone (1:1, v/v), and desorption solvent volumes: 200 μL. Under optimum conditions, the linearity range for polycyclic aromatic hydrocarbons determination was 0.2-200 ng mL^-1  with coefficient of determination> 0.993, limit of detection = 0.09-0.21 ng mL^-1 , limit of quantitation = 0.3-0.7 ng mL^-1 , and relative standard deviation < 8.1%, respectively. Relative recoveries in spiked real samples ranged from 94.67 to 109.45 % with standard deviation < 6.05%. The proposed method is effective, sensitive, reusable and it is promising for the analysis of polycyclic aromatic hydrocarbons residues in environmental samples. This article is protected by copyright. All rights reserved.