Pipette Tip Research Articles

Magnetic relaxation switch biosensor for detection of Vibrio parahaemolyticus based on photocleavable hydrogel

BackgroundFoodborne pathogens, particularly Vibrio parahaemolyticus (VP) found in seafood, pose significant health risks, including abdominal pain, nausea, and even death. Rapid, accurate, and sensitive detection of these pathogens is crucial for food safety and public health. However, existing detection methods often require complex sample pretreatment, which limits their practical application. This study aims to overcome these limitations by developing a label-free magnetic relaxation switch (MRS) biosensor for the detection of VP, utilizing a photocleavable sol-gel phase transition system for improved efficiency and accuracy. ResultsIn this work, a tag-free magnetic relaxation switch (MRS) biosensor was designed for the detection of Vibrio parahaemolyticus (VP), based on a photocleavable sol-gel phase transition system. A large amount of lithium acyl hypophosphite (LAP), gold nanoparticles (AuNPs), and single-stranded DNA (ssDNA) loaded on the surface of Ti3C2Tx MXene acted as the signal unit LAP-MXene@AuNPs-ssDNA. The pipette tip served as a reaction vessel, and when VP was present, Apt specifically captured VP and released the signal units. The released signal units were then injected into the low-field nuclear magnetic resonance (LF-NMR) test solution, a gel formed by crosslinking of disulfide bonds. The gel was cleaved by LAPs on the signal units under ultraviolet (UV) irradiation, triggering a gel-sol phase transition, which increased transverse relaxation time (T2), thus enabling the detection of VP. Under the optimal experimental conditions, the linear range and detection limit for VP were 102 ∼ 108 CFU/mL and 10 CFU/mL, respectively. Significance and NoveltyThe simplified biometric identification process in the pipette tip reduces errors from multiple sample transfers, enhancing efficiency. The use of photocleavable hydrogel for signal output eliminates issues associated with magnetic material aggregation, significantly improving detection precision. The assay is of good selectivity, stability reproducibility, and convenience, having a broad application prospect in the rapid detection of pathogenic bacteria in the field.

Development of a novel second-generation polyester dendritic functionalized graphene oxide for efficient pipette tip micro solid-phase extraction and detection of venlafaxine and desvenlafaxine in urine

Development of a novel second-generation polyester dendritic functionalized graphene oxide for efficient pipette tip micro solid-phase extraction and detection of venlafaxine and desvenlafaxine in urine

Fabrication and application of aminated metal–organic cages doped monolithic column for pipette tip micro solid-phase extraction of eight phenolic compounds in milk

A Zr-based metal–organic tetrahedron (ZrT-1-NH2) doped monolithic column was sythesized and applied for pipette tip micro solid-phase extraction (PT-μSPE) of 8 phenolic compounds. Scanning electron microscopy, energy dispersive spectrometry, Fourier transform infrared spectroscopy, thermogravimetric analysis and N2 adsorption and desorption experiment were employed to characterize the morphology, composition, structure and thermal stability of the monolithic column. The experimental results showed that the monolithic column had good stability and excellent adsorption selectivity for phenolic compounds. The adsorption mechanism was speculated to be π-π stacking and H-bond interaction based on ESP maps. After the extraction conditions were optimized, a PT-μSPE-high performance liquid chromatography-ultraviolet detector (HPLC-UV) method was established for the detection of 8 phenolic compounds in milk. The PT-μSPE-HPLC-UV method has wide linearities (0.3–1000 μg L−1) (R2 > 0.997), low limits of detection (0.1–0.3 μg L−1), satisfactory recoveries (80.5–113.6 %) and high precision (RSDs < 6.7 %). Thus, the ZrT-1-NH2 doped monolithic column is an ideal medium for the separation and determinaton of phenolic compounds in milk.

Optimization of a disposable pipette tips extraction (DPX) for the analysis of psychoactive substances in sweat specimens using Design of Experiments.

Novel psychoactive substances (NPS) continue to emerge in the marketplace and are often found as substances in traditional illicit drug materials, and users are often unaware of the presence of other drugs. The proper identification and confirmation of the exposure to a drug is made possible when a biological specimen is collected and tested. Sweat is an alternative biological matrix of great interest for clinical, and forensic analysis. One of the reasons is attributed to its expanded drug detection window, enabling a greater monitoring capacity, and provision of information on prospective drug use. However, the concentrations of drugs in sweat samples are often low, which requires highly sensitive and selective methods. Disposable pipette tips extraction (DPX) is a new miniaturized solid phase extraction technique capable of efficiently extracting analytes from biological specimens, providing high recoveries, and requiring minimized solvent use. This study describes the development and optimization of two methods for the extraction of basic and neutral psychoactive substances from sweat samples using GC-MS and Design of Experiments (DoE). The following extraction parameters were optimized by DoE techniques: sample volume, elution solvent volume, washing solvent volume, sample aspiration time, elution solvent aspiration time, and number of cycles performed, including the elution step. It was possible to design a simple extraction protocol that provided optimized recoveries for both basic and neutral compounds. The sum of analyte areas increased at a rate of 54.7% for compounds of basic character and 39.2% for compounds of neutral character. Therefore, our results were satisfactory, demonstrating that DPX can be successfully used for extracting the target drugs from sweat samples.

Development of an Automated, Ultra-Rapid Bottom-Up Proteomics Workflow Utilizing Alginate-Based Hydrogels.

A new approach to sample preparation and enzymatic digestion in bottom-up proteomics has been developed using alginate-based hydrogel entrapment of enzymes. This hydrogel facilitates rapid and room-temperature digestions with multienzyme capabilities. Three methodologies were tested: within microcentrifuge tubes, in situ pipette tips, and automated robotic liquid handling. Factorial experimental design identified a 1 h, room temperature, pepsin-trypsin dual-enzyme digestion as optimal for sequence coverage and protein group identification, comparable to a gold-standard overnight proteomic protocol. This method promises significant advancements in proteomic analysis by enhancing reusability, speed, throughput, convenience, and cost-effectiveness, without hindering digestion efficiency.

Effect of capillary action and gravitational force on resistive pulse sensing with nanopipettes

In Resistive Pulse Sensing, nanoparticles dispersed in solution are individually detected and characterized during their translocation through a narrow pore or channel. Electrophoretic force and fluid flow can be precisely adjusted to direct nanoparticles toward the sensing zone. The impact of various factors on nanoparticle translocation dynamics, including solution ionic strength, pH, applied potential difference, and pipette tip geometry, has been extensively investigated. In this work, we focus on the role of pipette filling height, an experimental parameter often overlooked despite its significant impact on the overall pressure gradient and the resulting flow through the pipette tip. We used a solution of NaCl 150 mM plus 0.1 % v/v Triton X-100 at pH 7.2, a pipette with radius of approximately 200 nm and a voltage of ± 200 mV. Our findings reveal that the pipette filling height emerges as the critical factor dictating the translocation direction of negatively charged 160 nm PMMA particles and surpassing the combined effect of electrokinetic forces. Ultimately, our results indicate that considering the pipette filling level could enhance the accurate interpretation of experimental results, offering an additional parameter for fine-tuning nanoparticles dynamics, thus providing a valuable tool to researchers in this field.

Insights into type 2 diabetes mellitus in atrial fibrillation patients: a proteomics approach

Abstract Introduction Atrial fibrillation (AF) and Type 2 Diabetes Mellitus (T2DM) are two closely interconnected conditions, sharing a complex relationship within cardiac pathophysiology. Common risk factors such as obesity, hypertension, inflammation, and endothelial dysfunction contribute to their coexistence. T2DM is known to drive cardiac fibrosis and promote electrical and structural remodeling of the heart, creating a substrate conducive to AF onset, while AF in T2DM patients increases the risk of adverse cardiovascular outcomes, such as stroke. Understanding this complex relationship is pivotal for improving the therapeutic and preventive strategies for these patients. This study aims to examine the proteomic differences between AF patients with and without T2DM, providing novel insights into pathophysiological mechanisms and identifying novel therapeutic targets and biomarkers. Methods In total, 14 AF patients undergoing open-heart surgery, comprising of 6 T2DM individuals and 8 non-T2DM individuals have been included. The mean age of the T2DM patients was 69.5 ± 10 years, while the non-T2DM was 69.3 ± 8.2 and BMI was 29.2 ± 2.9 and 29.5 ± 3 respectively. Right atrial appendages (RAA) from these patients were obtained in an RNA stabilization solution during open-heart surgery and processed using the phenol-based method for protein extraction. The proteins were digested with trypsin to generate peptides, followed by an additional clean-up step using C18 pipette tips. The prepared peptide samples were analyzed by employing a label-free-based quantitative (LFQ) approach, using a C18 (75cmx75cm) column. Proteomic analysis was performed using a Nano liquid chromatography system coupled to tandem mass spectrometer (nano LC-MS/MS), followed by a comprehensive bioinformatics analysis, using appropriate software. Results A total of 1548 proteins were identified, of which 899 could be quantified using LFQ analysis. Applying strict significance criteria, including FDR &amp;lt;0.1 and Abundance ratio (AR)&amp;gt;2 or &amp;lt;0.5, we identified 100 differential expressed proteins, with 21 upregulated and 79 downregulated in T2DM (Fig.1). Most notably, DPP9 and ATP1A2 were overexpressed in hearts of AF patients with T2DM (AR=100), while INPPL1 and ARID5A were underexpressed (AR=0.01), thereby representing attractive therapeutic targets. In pathway enrichment analysis (Fig.2), the dysregulated proteins participate in noteworthy pathways, including Non-alcoholic fatty liver disease (NAFLD), Type II diabetes mellitus, and Insulin signaling pathway. Conclusion Given the increased morbidity associated with the coexistence of AF and T2DM, there is a pressing need for novel therapeutic strategies tailored to this patient population. While AF and T2DM share certain molecular characteristics in the heart, this study emphasizes the necessity for further evaluation and validation of the distinct proteomic signatures identified.Fig.1:Volcano PlotFig.2:Protein Enrichment Network

An Experimental Device with Different Widths for Wound Healing Assay

Introduction: Cellular wound healing assay is an important experimental technique for detecting cell migration in vitro. Scratching on monolayer cells using a pipette tip is commonly used. However, it is difficult to guarantee the scratch with the same width, and the initial scratch width has a large impact on the experimental results for different treatment factors or different cell types. To optimize this assay for diverse experimental requirements, we developed an experimental device capable of generating scratches with variable widths. Methods: Our device offers the flexibility of selecting among four widths to create cell scratches, enabling the choice of an optimal initial scratch width for specific cell types and experimental conditions. Results: This device produced straight, clean wounds with precise widths. Comparing cell growth in the four width wounds, Hepa1-6 and HUMSCs showed the greatest difference in 0.6 cm wound, 143B at 0.9 cm wound and urine-derived stem cells at 1.2 cm wound were significantly different, which suggests that the width of the wounds has a huge impact on the experimental results. Compared to other wound inserts on the market, our device is more efficient and economical. Conclusion: This versatile and practical device provides a valuable solution for studying cell migration, facilitating a deeper understanding of cellular behaviors and the development of therapeutic strategies.

Automated kapok fiber-based pipette-tip solid-phase extraction coupled with liquid chromatography-tandem mass spectrometry for rapid and sensitive analysis of tyrosine kinase inhibitors in plasma

This study delineates the development of a novel automated pipette-tip solid-phase extraction (SPE) methodology, employing kapok fiber as a naturally efficient and cost-effective adsorbent for the selective extraction of eleven tyrosine kinase inhibitors (TKIs) from plasma. The uniqueness of this method lies in its assembly, where kapok fibers are ingeniously wrapped around a stainless-steel spring within the pipette tip, ensuring an obstruction-free central space for effortless solution aspiration and dispensation. This design significantly minimizes backpressure, enhancing operational efficiency and ensuring compatibility with pipettors, including the implementation of an electric pipettor to streamline the sample preparation process and facilitate automation. The method's analytical performance, rigorously validated through liquid chromatography-tandem mass spectrometry, exhibits outstanding linearity in ranges of 0.1/0.5–200 ng mL-1 (R² > 0.993), commendable accuracy (86.3%–114.8%), and consistent precision (3.4–11.3%), alongside remarkably low detection limits that span from 0.024 to 0.130 ng mL-1. The assembly of kapok fiber within the pipette tip, in this unique configuration, results in a practical, cost-effective, eco-friendly, and automated pipette-tip SPE method. This innovation signifies a significant advancement in bioanalytical methodologies, offering an efficient and sustainable approach for extracting analytes from complex biological samples. This process notably enhances both the sensitivity and selectivity of subsequent instrumental analyses.

A multicommuted flow system with a solid–liquid extraction chamber to extract and quantify total phenolic compounds from solid samples

Multicommutation significantly enhances the versatility of flow systems by integrating solenoid micro-pumps or valves. In this novel approach, the flow system was fitted with four solenoid micro-pumps to enhance mixing conditions, minimize reagent use and waste production, and quantify total phenolic compounds (TPC) via the Folin-Ciocalteu method. The extraction module was constructed with a 1000 µL pipette tip, a frit, and cotton used as a filter. The fluidized bed column was continuously agitated with a vibratory shaker, the extraction solution (ethanol 5 % (v/v)), and the solid samples (50 mg). The extraction of TPC was started by pumping the extraction solution through P1 (150 pulses). The analytical cycle was established by delivering the extraction solution and reagents through P1 (4 pulses), P3 (Folin-Ciocalteu 20 % (v/v); 1 pulse), and P4 (sodium carbonate 2 % (w/v); 1 pulse). These aliquots were rapidly mixed at the interfaces, initiating the first sampling cycle. This process was repeated seven times to create the sample zone and was directed towards detection at 740 nm by activating P2. Under optimized experimental conditions, a linear response was observed from 1 to 20 mg L-1 gallic acid, as described by the equation Absorbance = 0.023 + 0.028C (mg L-1), r = 0.997. At a 99.7 % confidence level, the detection limit, coefficient of variation (n = 11; 10 mg L-1), and sampling rate were determined to be 188 µg L-1, 0.1 %, and 100 determinations per hour, respectively. The consumption of reagents for each determination was estimated at 0.95 mg of sodium carbonate and 9.5 µL of Folin-Ciocalteu, resulting in 3.4 mL of waste generated. Phenolic compounds were quantified between 694 and 1760 mg in 100 g−1 food flour dry samples. Results obtained by the proposed process agreed with those obtained with batch extractions (95 % confidence level). Typical characteristics of systems that use solenoid micro-pumps are portability, cost-effectiveness, low energy consumption, improved mixing, and reproducibility in handling micro-volume solutions. The proposed procedure demonstrates its versatility and effectiveness by offering a practical alternative for extracting and quantifying total phenolic compounds in various solid matrices. This approach proves to be a superior option compared to existing methodologies.

A Polyacrylate Cotton-based Pipette Tip Micro-solid-phase Extraction Technique Coupled with High-performance Liquid Chromatography for Carvedilol Determination in Aqueous Media

Introduction: In this work, a polyacrylate polymer was synthesized into a pipette tip containing cotton fibers and used to extract carvedilol from water and urine samples. Methods: A high-performance liquid chromatography-ultraviolet detection method was developed, which demonstrated the suitability of the purposed pipette tip micro-solid-phase extraction device. Factors affecting the fabrication procedure and polymer quality were studied and optimized. In the next step, the sample preparation process (including extraction and desorption) was fully optimized, and the optimized method was validated. Results: A coating with suitable mechanical and chemical stability was achieved. Its structure was successfully characterized by Fourier transform infrared spectroscopy and scanning electron microscopy. Within-batch and between-batch fabrication reproducibility were obtained at 3.0 and 9.0 %, respectively. The developed method displayed a limit of detection of 1.1 µg L-1 when 1.5 mL of sample was processed, and it was linear in the concentration range of 3.3-350 µg L-1 with LLOQ of 5 µg L-1 . The polyacrylate cotton-based pipette tip was finally used to extract carvedilol from aqueous media with acceptable recoveries of 92-106%. Conclusion: The proposed method is simple and fast and requires low sample volumes. In addition, this method has been evaluated in terms of greenness with three different tools, and the evaluation results with all three tools have shown that this method is one of the green and environmentally friendly methods.

First Report of Strawberry Anthracnose Crown Rot Caused by Colletotrichum siamense in New England.

In the summer of 2023, the Connecticut Agricultural Experiment Station was contacted by a farm in southern Connecticut due to reports of strawberry (Fragaria × ananassa) plants showing signs of severe wilting and crown rot across multiple fields, covering ~20 hectares. Cut crowns from diseased plants had marbled red and white lesions typically associated with anthracnose crown rot (ACR). Symptomatic plants were collected from five June-bearing cultivars (cvs. AC Valley Sunset, Lyla, Dickens, and Allstar) spanning four non-adjacent fields with incidence ranging from 5-90% and severity ranging mild wilting in low incidence fields to severe wilting/mortality in high incidence fields. Internal tissue from diseased crowns was surface sterilized in 0.6% NaOCL for 3 minutes, rinsed with sterile water, and plated on potato dextrose agar. After one-week, hyphal tips of fungi were transferred to fresh plates which formed dense mycelial mats of fluffy, greyish-white hyphae. Orange spore masses formed near the center of the colonies, each of which contained numerous cylindrical and fusiform straight conidia, matching spores within the genus Colletotrichum (De Silva et al. 2019). Average conidia (n=192) length was 15.7 ± 1.6 µm and width was 5.4 ± 0.7 µm. Fungi matching this morphology were isolated from 83% of the collected symptomatic crowns and hyphae were collected from two isolates, CT5-1 and CT23-1, for DNA extraction using the GeneJET Plant Genomic DNA Purification Kit. PCR was performed using primers targeting actin (ACT), calmodulin (CAL), β-tubulin (TUB2), GAPDH (gpdA), and ITS, followed by Sanger sequencing, which yielded identical sequences for both isolates (CT5-1 Accessions numbers: PP002078-81, OR999066)(Carbone and Kohn 1999; Hassan et al. 2018; Templeton et al. 1992). These were combined with sequences from fourteen Colletotrichum genomes, all of which were aligned, trimmed, and concatenated using Mega11 (Tamura, Stecher, and Kumar 2021). Model selection was conducted using IQ-TREE and selected parameters were used to generate maximum-likelihood trees from all five loci individually and the concatenated sequence, all of which placed the isolates in a high confidence cluster with Colletotrichum siamense (Nguyen et al. 2015). To confirm the pathogenicity of the pathogen, strawberry plants (cv. Jewel) (n=5) five weeks after bare root transplant were infected. The base of each crown was penetrated 5 mm deep with a sterile 20 µL pipette tip and then inoculated with 10 µL of spores at a concentration of 106 spores/mL. Control plants (n=5) were inoculated with 10 µL of sterile water. Plants were maintained at 30°C day (16-hour)/20°C night (8-hour) in a growth chamber and assessed after 14-days. Four of the five inoculated plants had visible wilt symptoms and bisected crowns revealed the marbled red and white lesions typifying ACR. Control plants had no clear wilting and bisected crowns were visibly healthy. C. siamense re-isolated from infected tissue presented with identical hyphal /spore morphology and ITS/Tub2 were re-amplified and sequenced, yielding identical sequences to CT5-1. Plant inoculations with the same variety were repeated, yielding identical symptom development and crown lesions. C. siamense has been a dominant source of ACR throughout the southeastern US but has not previously been a major problem in the Northeast. Given the extent of the field infection, it is likely that these isolates can survive the colder winter temperatures of New England, but further experimentation is necessary to determine the extent of the pathogen's winter hardiness.

Enhanced detection of catecholamines in human urine using Cis-diol-microporous organic networks with PT-SPE and HPLC-MS/MS

A novel cis-diol-microporous organic networks (MONs-2OH) material was synthesized via room temperature and Sonogashira coupling reactions, which exhibits exceptional adsorption properties for catecholamines (CAs). MONs-2OH demonstrates robust hydrogen bonding and π-π stacking interactions, crucial for effective adsorption. The MONs-2OH was incorporated into pipette tip solid-phase extraction and developed a new method for detecting CAs in human urine using HPLC-MS/MS. Characterization of the adsorbent revealed its high stability, large specific surface area, abundant phenolic hydroxyl groups, rapid extraction speed, and superior adsorption efficiency. The method achieved a wide linear range (0.5–500 ng/mL), low detection limits (0.06–0.26 ng/mL), high accuracy (90.4 %-99.4 %), and excellent precision (RSD ≤ 10 %). Comparative studies showed MONs-2OH outperforms commercial adsorbents in terms of recovery and adsorption capacity. The results underscore the potential of MONs-2OH for rapid and sensitive CAs determination, offering significant advantages for the auxiliary diagnosis of depression and enhancing the application of PT-SPE in sample pretreatment.

Preparation and evaluation of polymeric ionic liquid functionalized microparticles as the efficient adsorbent for pipette tip solid phase extraction of sulfonamides

Sulfonamides (SAs) residues are commonly found in environmental samples, which is highly concerning for public safety and environmental protection. The detection of SAs is quite important but challenging. In this work, a kind of polymeric ionic liquid functionalized microparticles (PIL-FM) was synthesized via a simple free radical polymerization reaction, and applied as the adsorbent for pipette tip solid phase extraction (PT-SPE) of three SAs from river water, milk powder and honey samples. The adsorption performance of PIL-FM on SAs were evaluated using adsorption kinetics and adsorption isotherms, and the results showed that PIL-FM had the best selectivity for SMZ with the maximum adsorption capacity was as high as 45.05 mg·g−1. The extraction process was optimized and the adsorption mechanism was preliminarily discussed. PIL-FM has the excellent selectivity for SAs mainly because of the strong π-π interaction, and the electrostatic repulsion between them in the elution step also has a positive impact. Under optimal conditions, combined with HPLC, this PT-SPE method had wide linearity (0.2–100 μg·L−1, R2 ≥ 0.9998) and low limits of detection (0.06–0.08 μg·L−1). The intra-day and inter-day repeatability were found to be 3.7 %–4.6 % and 4.5 %–6.2 %, respectively. The suggested PT-SPE method is simple, low cost, rapid, and efficient to extract SAs, and can be applied for the monitoring of SAs residues in the aquatic environment and in food.

Surface amphiphilic hybrid porous polymers based on cage-like organosiloxanes for pipette tip solid-phase extraction of microcystins in water

The occurrence of microcystins (MCs) during harmful algal blooms (HABs) represents a major threat to freshwater environments. In this work, a novel surface amphiphilic hybrid porous polymers based on cage-like organosiloxanes (PCSs) was prepared for the enrichment of MCs. The copolymerization of bifunctional amphiphilic monomers, 2-methacryloyloxyethyl phosphorylcholine (MPC) and N-benzylquininium chloride (BQN), with the cross-linker methacryl substituted polyhedral oligomeric silsesquioxane (POSS) was achieved in an ionic liquid-based porogenic medium. The hierarchical porous structure, a variety of surface functional groups and weak hydrophilicity were well characterized on the prepared materials using scanning electron microscopy, nitrogen adsorption/desorption analysis, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, zeta potential analysis and water contact angle testing, respectively. The as-prepared surface amphiphilic PCSs was used as an adsorbent for pipette tip solid-phase extraction (PT-SPE) to enrich microcystins (MCs) from surface waters before their analysis by capillary electrochromatography (CEC) and liquid chromatography-mass spectrometry (LC-MS). Under the optimal conditions, the established PT-SPE-LC-MS method exhibited a wide linear range (10–10,000 ng L−1), low limits of detection (4.0–8.0 ng L−1) and satisfactory recoveries (89.5–102.8 %) for MCs. An adsorption mechanism involving electrostatic interactions, hydrogen bonding, hydrophilic interactions, and π-π stacking has been proposed. The findings suggest that the use of surface amphiphilic PCSs materials as adsorbents in the PT-SPE platform facilitates efficient enrichment of MCs for subsequent chromatographic analysis. These investigations offer a new perspective on the simple and uncomplicated pretreatment of complex environmental samples.

First Report of Stem Blight of Mungbean (Vigna radiata) Caused by Diaporthe longicolla in the United States.

Mungbean (Vigna radiata) is primarily grown in Asia and directly consumed by humans. U.S. consumers embraced mungbean as a plant-based protein in vegan eggs and meat substitutes. New cultivars are being developed for American farmers because of the crop's tolerance to heat and drought, and its adaptability to current farming infrastructure. Mungbean's short season complements various cropping systems such as intercropping, alternative cropping, and green manure. With rotations and inclusion with soybean systems, there is a concern about the overlap of common pathogens for soybean and mungbean. During August 2022 when mungbeans reached full maturity (growth stage R6), reddish-brown and necrotic stem lesions with linear rows of black pycnidia were observed on Berken and OK2000 cultivars at fields located in Hancock County, IA and Story County, IA in the United States. Pycnidia measured 0.5-0.6mm in length. Disease incidence was approximately 10% of plants in Hancock County, IA and less than 3% of plants in Story County, IA. Pycnidia from 16 plants were excised and immersed in a 0.5% NaOCl solution for 1 min, rinsed with autoclaved distilled water, and placed onto potato dextrose agar (PDA). Eighteen isolates were hyphal tipped and grown on PDA and were stored at 25°C. Isolates were then visually identified by culture and conidia morphology (Hobbs et al. 1985, Santos et al. 2011). Colonies were cream to white, dense, and floccose. Large black stromata were formed in a concentric pattern or scattered; alpha conidia were ellipsoidal. Template DNA for PCR amplification of the internal transcribed spacer region of the nuclear ribosomal DNA operon (ITS) and the beta-tubulin gene (TUB) was extracted from 18 isolates by scraping mycelia with a sterile pipette tip and transferring it into 50 ul of PrepMan Ultra Sample Reagent (Applied Biosystems, Foster City, California, USA). Fungal primers were ITS1 and ITS4 (White et al. 1990) and Bt-2F/Bt-2R (Udayanga et al. 2014). Sequences of isolates obtained from fields in both counties were identical, providing no species diversity. GenBank accession numbers for the ITS region were PP105598 and PP105599; PP108254 and PP108255 for TUB sequences. BLAST results showed the ITS 550/550 base pairs with type specimen D. longicolla ATCC 60326 GB NR_144924 and the TUB 446/446 base pairs with type specimen D. longicolla ATCC 60325 GB KJ610883. Thus, the isolates were identified as Diaporthe longicolla (Hobbs) J.M. Santos, Vrandecic & A.J.L. Phillips based on morphology and molecular characters (Santo et al 2011; Udayanga et al. 2014). To confirm the pathogenicity of the D. longicolla isolates, twenty mungbean plants (cv. Berken and OK2000) were grown in the greenhouse at 85% RH and 16hr light for 20 days. Inoculum was prepared by placing sterile toothpicks on 1/3 PDA with a single representative isolate from each field location for 21 days (Ghimire et al. 2019). Mungbean plants were grown in a 10cm-by-10cm pot containing a greenhouse professional growing mix (Sungrow, Agawam, Massachusetts, USA) and grown for 30 days post emergence. After 12 days of growing, a 3mm segment of the infested toothpick was inserted into a stem wound below the first trifoliate and sealed with parafilm. A sterile toothpick was inserted into the control plants. After 14 days, red lesions extended downward 1 to 3 cm from the inoculation site, and white mycelial was present in the wound. At 21 days red lesions spanned 3 to 9 cm upward and downward from the inoculation site. Pycnidia were present on collapsed stem tissue, and leaves became chlorotic. Damage was limited to 2mm from the mock-inoculation site, with no discoloration in the control plants. Symptomatic tissues were plated and compared to the original isolates. Alpha conidia were ellipsoidal with the base end rounded. To our knowledge, this is the first report of Diaporthe longicolla causing disease on mungbean within the U.S. and worldwide. The presence of this disease in two locations suggests the potential for Diaporthe longicolla to be a serious disease of mungbean in the future.

Melt-blown polypropylene nonwoven as an efficient and eco-economic sorbent for pipette tip micro-solid phase extraction for the determination of tyrosine kinase inhibitors

BackgroundThe detection of tyrosine kinase inhibitors (TKIs) in biological fluids is essential due to their critical role in cancer therapy and the variability in individual drug metabolism, which necessitates precise dosing. Traditional methods for analyzing TKIs in biological fluids, such as blood plasma, typically involve complex sample preparation techniques that can be resource-intensive, environmentally burdensome, and not sufficiently sensitive for low-concentration analytes. There is a pressing need for more efficient, economical, and environmentally friendly methods that can enhance sensitivity and throughput without compromising accuracy. ResultsThis study explores the use of melt-blown polypropylene nonwoven (MBPP), commonly found in face masks, as a novel sorbent for pipette-tip micro-solid phase extraction (PT-μSPE). MBPP demonstrated excellent hydrophobicity and significant mesoporous adsorption capacity. An extraction device was fashioned by inserting a segment of MBPP (15 mg) into a 200 μL disposable plastic pipette tip, which was then attached to a 2.5 mL disposable plastic syringe. The MBPP's fabric form removes the need for a frit, allowing the extraction process to be completed in just 3 min through simple plunger manipulation. The method achieved extraction recoveries ranging from 60.5 % to nearly 100 %. Subsequent method validation using liquid chromatography-tandem mass spectrometry (LC-MS/MS) showed satisfactory linearity (coefficient of determination R2 > 0.993), accuracy (relative recoveries: 86.3%–114.8 %), and precision (relative standard deviation: 3.4%–11.3 %), with detection limits between 0.022 and 0.135 ng mL−1. SignificanceThe introduction of MBPP for PT-μSPE represents a significant advancement in the bioanalytical detection of TKIs, offering a highly efficient, cost-effective, and environmentally sustainable method. It compares favorably with existing techniques, offering advantages in terms of cost, environmental impact, and ease of use. This approach has the potential to be widely adopted for routine monitoring of TKIs in clinical settings.

Interactions of per- and polyfluoroalkyl substances with polypropylene plastic and borosilicate glass: Resolving key uncertainties for accurate analysis

This study addresses critical uncertainties regarding the interactions of per- and polyfluoroalkyl substances (PFAS) with plastic (e.g., polypropylene, PP) and borosilicate glass materials, which are either recommended or advised against by prevalent analytical methods. Our results indicate that borosilicate glass minimally adsorbs short-chain, moderate-chain, and some long-chain PFAS with <11 perfluorinated carbons, maintaining the integrity of PFAS solutions. The ratios of PFAS concentrations in solutions contained in borosilicate glass compared to those in solutions unaffected by laboratory ware interaction showed minimal deviation, with most compounds displaying values within the established acceptable limits of 87 % to 107 % for C3‒C10 PFAS. Similarly, PP tubes, syringes, and pipette tips also demonstrated minimal or moderate interactions: perfluorooctanoate (PFOA) and perfluorooctanesulfonate (PFOS) showed relatively consistent recoveries in PP syringes and pipette tips, ranging from 96 % to 107 % and minimal adsorption to PP centrifuge tubes during a 105-h contact period. Both materials, however, showed significant adsorption of the longest-chain PFAS in this study (C11), pointing to enhanced adsorption due to their hydrophobic nature. However, microfilters demonstrate significant adsorption of long-chain PFAS, including PFOA and PFOS. We developed a Gradient Flush Syringe Method to mitigate adsorption losses on syringe filters, achieved a significant reduction in C11 PFAS retention on filters from >90 % to nearly 0.01 %. Methanol-induced matrix effects were also studied, showed that increasing methanol concentrations led to artificially increasing the analyzed concentration of short-chain PFAS from the true concentration.

On-site extraction of phenoxycarboxylic acid herbicides in environmental waters utilizing monolith-based in-tip microextraction technique

On-site extraction plays a significant role in the reliable quantification of strong polar phenoxycarboxylic acid herbicides (PCAs) in aqueous samples. In current study, a new technique for the field sample preparation of PCAs was developed by means of three channels in-tip microextraction device (TCIM). To capture PCAs effectively, an extraction phase based on monolith (EPM) using vinylimidazole and divinylbenzene/ethylene dimethacrylate as monomer and cross-linkers, respectively, was in-situ synthesized in pipette tips. The EPM fabricated at optimal conditions were characterized by a series of techniques and employed as the adsorbent of TCIM for the on-site extraction of PCAs. The adsorption isotherm was studied so as to inspect the extraction behaviors of EPM towards PCAs. Results revealed that the proposed EPM/TCIM presented satisfactory extraction performance towards PCAs through multiple interactions. The enrichment factors and adsorption capacity were 74–277 and 20 mg g-1, respectively. Under the most beneficial extraction parameters, the developed EPM/TCIM was successfully employed to on-site extract PCAs, and then combining with HPLC equipped with diode array detector to monitor trace PCAs in actual waters. The limits of detection (LODs) towards investigated PCAs varied from 0.071 μg/L to 0.30 μg/L. In addition, the accuracy of established approach was inspected with documented method. Compared with existing lab-based sample preparation approaches, the introduced field sample preparation technique exhibits some merits such as avoidance of transporting large volume of water, prevention of analytes loss during sampling procedure, less usage of organic solvent and achievement of satisfactory efficient in sample preparation.

MonoTip C18 pipette tip solid-phase extraction coupled with liquid chromatography-tandem mass spectrometry enables rapid and automated therapeutic drug monitoring of tyrosine kinase inhibitors

This work presents an advanced automated monolithic C18 pipette-tip solid-phase extraction (PT-SPE) method seamlessly integrated with liquid chromatography-tandem mass spectrometry (LC-MS/MS) for precise therapeutic drug monitoring of eleven tyrosine kinase inhibitors (TKIs) in biological samples. Commercially available MonoTip C18 columns facilitate superior extraction efficiency and selectivity from complex biological matrices owing to their large surface areas and enhanced mass transfer capabilities. The sample preparation process, conducted by aspirating and dispensing solutions using a pipettor, completes the overall extraction process within 3 min. The method validation demonstrated excellent linearity within the range of 0.2/0.5/0.8 to 200 ng/mL, with detection limits ranging from 0.049 to 0.206 ng/mL. The method exhibited outstanding accuracy and precision, with intraday relative recovery rates ranging from 96.3 % to 115.0 % and interday recovery rates ranging from 95.0 % to 115.7 %, with coefficient of variation values consistently below 13.8 %. The proposed method is distinguished by its exceptional efficiency, reduced solvent use, enhanced environmental sustainability, and streamlined automation—key advantages in the realm of clinical therapeutic drug monitoring of TKIs. Overall, the MonoTip C18 PT-SPE technique, coupled with LC-MS/MS, offers a formidable, eco-friendly, and effective strategy for the TDM of TKIs, marking a significant advancement in the field.