Challenges and opportunities in blood flow through porous substrate: A design and interface perspective of dried blood spot

Liquid-liquid extraction solvent selection for comparing illegal drugs in whole blood and dried blood spot with LC-MS-MS

This study focused on the simultaneous detection of amphetamine, 3,4-methylenedioxy methamphetamine, morphine, benzoylecgonine, and 11-nor-9-carboxy-tetrahydrocannabinol in whole blood and dried blood spot (DBS). It is aimed to select a solvent mixture for liquid-liquid extraction technique employing liquid chromatography-tandem mass spectrometry (LC-MS-MS). The obtained DBS results were compared with the whole blood samples results. A simple, rapid, and reliable LC-MS-MS method was developed and validated for all analytes in whole blood and DBS. LC was performed on a Hypersil Gold C18 column with an initial gradient of 0.01% formic acid, 5 mM ammonium format buffer in water, and acetonitrile at 0.3 ml/min with 7.5 min runtime. A methanol:acetonitrile (40:60 v/v) mixture was selected for both matrices. Limit of quantitation (LOQ) values were 10-25 ng/mL; linear ranges were LOQ-500 ng/ml for all analytes; correlation coefficients were greater than 0.99, and all calibrator concentrations were within 20%. Analytical recovery in blood and DBS ranged from 84.9% to 113.2% of the expected concentration for both intra- and inter-day. Analytes were stable for 1, 10, and 30 days after three freeze/thaw cycles. It was determined that the variances of the results obtained with the two matrices in the comparison study were equal for each analyte, and the results were highly correlated (r = 0.9625). A sensitive, accurate, and reliable chromatographic method was developed to determine amphetamine, 3,4-methylenedioxy methamphetamine, morphine, benzoylecgonine, and cannabis, by performing the same preliminary steps with whole blood and dried blood spots. It was observed that the results obtained in these two matrices were compatible and interchangeable when statistically compared.

Blood-clotting model and simulation analysis of polyvinyl alcohol-chitosan composite hemostatic materials

The blood-clotting performance and characteristics of hemostatic materials are critical for their development and actual application. Based on the theory of porous media and characteristics of a non-Newtonian fluid, this study proposed an adsorption factor to characterize the porosity generation and blood coagulation process of hemostatic materials. On this basis, we constructed a physical model of blood coagulation in a porous medium integrated with the power-law fluid model to study the proposed poly(vinyl alcohol)-chitosan (PVA-CS) composite hemostatic material. Moreover, we simulated the dynamic blood flow process and blood coagulation process in the PVA-CS hemostatic material by introducing the physical model. The simulation results show that the blood begins to coagulate, which affects the porosity and permeability of the blood-containing area, resulting in changing the porosity after blood flowed into the hemostatic material. The porosity, permeability, and blood flow rate will approach zero until the generated blood coagulation entirely blocked the porous medium. Besides, simulation can provide the pressure and velocity distribution varying in the coagulation process of hemostatic materials. The temperature will also influence the hemostatic performance of the PVA-CS material. In all, the proposed simulation method enabled the coagulation mechanism of PVA-CS to be revealed from the perspective of blood flow in porous media combined with the adsorption factor.

In vitro testing of the hemaPEN microsampling device for the quantification of acetaminophen in human blood

Background: The hemaPEN is a liquid microsampling device for the reproducible collection and storage of blood samples as dried blood spots, for subsequent quantitative analysis. Materials & methods: We examined the device’s ability to collect accurate and precise blood volumes, at different hematocrit levels, via in vitro studies using acetaminophen in human blood. We also investigated the impact of different user training approaches on device performance. Results: The hemaPEN demonstrated acceptable volumetric accuracy and precision, regardless of the training medium used. Issues with apparent hematocrit-dependent bias were found to be associated with the extraction process, rather than the volumetric performance of the device. Conclusion: The hemaPEN is capable of readily producing high quality blood microsamples for reproducible and accurate quantitative bioanalysis.

Liquid Spreading Induced by In Situ Generation of Metallic Nanoparticles

Spreading or pinning of a liquid drop on a solid substrate is determined by the surface energy of solid and liquid, topography of substrate surface, and different external forces like electric field, magnetic field, and vibration. Here we present a novel mechanism of depinning, driven by in situ generation of a species following reaction between a constituent of the droplet and one in the substrate. In particular, fluoro-carbon (FC) functionalized agarose and pHEMA gels are used as the substrates; the substrate is soaked with chloroauric acid. A drop of poly(dimethylsiloxane) (PDMS) mixed with the cross-linking agent is dispensed on it. The drop does not spread in absence of the salt, but as the salt concentration increases, the spreading diameter increases with decrease in the contact angle. The Si-H group, present as a constituent in the cross-linking agent, reduces the salt, leading to in situ generation of gold nanoparticles, that mitigates the pinning effect of the drop and the drop spreads.

Technological advancement in dry blood matrix microsampling and its clinical relevance in quantitative drug analysis

In the past few decades, dried blood matrix biosampling has witnessed a marvelous interest among the researcher due to its user-friendly operation during blood sampling in preclinical and clinical applications. It also complies with the basic 3Rs (reduce, reuse and recycle) philosophy. Because of comparative simplicity, a huge number of researchers are paying attention to its technological advancements for widespread application in the bioanalysis and diagnosis arena. In this review, we have explained different approaches to be considered during dried blood matrix based microsampling including their clinical relevance in therapeutic drug monitoring. We have also discussed various strategies for avoiding and minimizing major unwanted analytical interferences associated with this technique during drug quantification. Further, various recent technological advancement in microsampling devices has been discussed correlating their clinical applications.

What the lab can and cannot do: clinical interpretation of drug testing results

Urine drug testing is one of the objective tools available to assess adherence. To monitor adherence, quantitative urinary results can assist in differentiating "new" drug use from "previous" (historical) drug use. "Spikes" in urinary concentration can assist in identifying patterns of drug use. Coupled chromatographic-mass spectrometric methods are capable of identifying very small amounts of analyte and can make clinical interpretation rather challenging, specifically for drugs that have a longer half-life. Polypharmacy is common in treatment and rehabilitation programs because of co-morbidities. Medications prescribed for comorbidities can cause drug-drug interaction and phenoconversion of genotypic extensive metabolizers into phenotypic poor metabolizers of the treatment drug. This can have significant impact on both pharmacokinetic (PK) and pharmacodynamic properties of the treatment drug. Therapeutic drug monitoring (TDM) coupled with PKs can assist in interpreting the effects of phenoconversion. TDM-PKs reflects the cumulative effects of pathophysiological changes in the patient as well as drug-drug interactions and should be considered for treatment medications/drugs used to manage pain and treat substance abuse. Since only a few enzyme immunoassays for TDM are available, this is a unique opportunity for clinical laboratory scientists to develop TDM-PK protocols that can have a significant impact on patient care and personalized medicine. Interpretation of drug screening results should be done with caution while considering pharmacological properties and the presence or absence of the parent drug and its metabolites. The objective of this manuscript is to review and address the variables that influence interpretation of different drugs analyzed from a rehabilitation and treatment programs perspective.

Metabolomic profiling of bloodstains on various absorbent and non-absorbent surfaces

Bloodstains found at crime scenes contain immense information about the crime; thus, studies involving analysis of small molecules in bloodstains have been conducted. However, most of these studies have not accounted for the difference in the results of small molecule analysis due to the surface of bloodstains. To evaluate the "surface effect," we prepared bloodstains on seven surfaces, including both absorbent and non-absorbent surfaces, and performed global small molecule analysis by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). We used three indicators: (1) count recovery rate (%) of molecular features (MFs), (2) the number of MFs extracted from the surface without bloodstains, and (3) difference in abundance recovery rate (%) of MFs, to determine the ranking of the seven surfaces in the order of their similarity with blood. We also confirmed the correlation between each surface and blood through multivariate analysis. We found that the non-absorbent surfaces ranked better than the absorbent surfaces; wooden flooring was ranked as the most efficient surface, followed by stainless, vinyl flooring, glass, tile, filter paper, and mixed cotton. This study will help in the selection of the most efficient surface for collection of bloodstains for small molecule analysis from a crime scene. This is the first study to identify the effects of surface on extraction of global small molecules from bloodstains; it will help forensic scientists in obtaining more accurate information from small molecules present in the bloodstains collected at the field. Graphical abstract.