Analysis Of Biomedical Samples Research Articles

On-site detection and laboratory verification of the presence of nerve agent biomarkers using dried blood spots

The analysis of biomedical samples is important for the investigation of the alleged exposure to chemical warfare agents. The present study aims to use dried blood spots for portable detection and laboratory verification of organophosphate poisoning. After in-vitro incubation of blood with Novichok A-230, A-232 and A-234 and sarin, a volume of 25 and 50 µL was spotted on a protein saver card. Subsequently, the dried spots were extracted and analyzed by a mobile cholinesterase test kit. In addition, butyrylcholinesterase (BChE) was isolated and digested by pepsin followed by analysis with liquid chromatography tandem mass spectrometry (LC-MS/MS). The fluoride-activated samples were analyzed by gas chromatography tandem mass spectrometry (GC–MS/MS) and LC-MS/MS. It was found that the CWA induced cholinesterase inhibition was remarkably stable in dried blood spots. Even after at least one month storage under ambient conditions, the same linear reduction was visible as function of nerve agent exposure. Additionally, nonapeptide adducts were identified by LC-MS/MS one month after exposure. Also, intact Novichok nerve agents and regenerated sarin were observed by GC–MS/MS. In addition to the stability of the sample, important benefits of the proposed method include the less invasive sample collection and safer and easier shipping and storage conditions. In conclusion, this study shows the feasibility of using on-site detection and state-of-the-art laboratory analysis of dried blood spots for unambiguous verification of nerve agent exposure.

Double Trap Interface: A novel gas interface for high throughput analysis of biomedical samples by AMS

Although Accelerator Mass Spectrometry (AMS) offers unparalleled sensitivity by investigating the fate of 14C-labeled compounds within the organism, its widespread use in ADME (absorption, distribution, metabolism, excretion) studies is limited. Conventional approaches based on Liquid Scintillation Counting (LSC) are still preferred, in particular because of complexity and costs associated with AMS measurements. Progress made over the last decade towards more compact AMS systems increased the interest in a combustion-based AMS approach allowing the analysis of samples in gaseous form. Thus, a novel gas Double Trap Interface (DTI) was designed, providing high sample throughput for the analysis of biomedical samples. DTI allows the coupling of an Elemental Analyzer (EA) for sample combustion to the hybrid ion source of a MICADAS (MIni CArbon DAting System) AMS system. The performance was evaluated in two studies through the analysis of more than 1000 samples from 14C-labeled biomatrices and fractions collected after liquid chromatography (LC). The covered activity ranged from 1 to 1000 mBq/g for labeled biomatrices and from 1 to 10000 mBq/g(C) for LC fractions. The implemented routine allows automated measurements requiring less than 5 min per sample (12–13 analyses per hour) without the need for sample conversion to graphite.

Mass spectrometric analysis of adducts of sulfur mustard analogues to human plasma proteins: approach towards chemical provenancing in biomedical samples.

The primary aim of this study was to identify biomarkers of exposure to some so-called Schedule 1 sulfur mustard (HD) analogues, in order to facilitate and expedite their retrospective analysis in case of alleged use of such compounds. Since these HD analogues can be regarded as model compounds for possible impurities of HD formed during synthesis processes, the secondary aim was to explore to which extent these biomarkers can be used for chemical provenancing of HD in case biomedical samples are available. While the use of chemical attribution signatures (CAS) for neat chemicals or for environmental samples has been addressed quite frequently, the use of CAS for investigating impurities in biomedical samples has been addressed only scarcely. Human plasma was exposed to each of the five HD analogues. After pronase or proteinase K digestion of precipitated protein and sample work-up, the histidine (His) and tripeptide (CPF) adducts to proteins were analyzed, respectively. Adducts of the analogues could still be unambiguously identified next to the main HD adducts in processed plasma samples after exposure to HD mixed with each of the analogues, at a 1% level relative to HD. In conclusion, we have identified plasma protein adducts of a number of HD analogues, which can be used as biomarkers to assess an exposure to these Schedule 1 chemicals. We have shown that adducts of these analogues can still be analyzed after work-up of plasma samples which had been exposed to these analogues in a mixture with HD, supporting the hypothesis that biomedical sample analysis might be useful for chemical provenancing.

The assessment of the usability of selected instrumental techniques for the elemental analysis of biomedical samples

The fundamental role of major, minor and trace elements in different physiological and pathological processes occurring in living organism makes that elemental analysis of biomedical samples becomes more and more popular issue. The most often used tools for analysis of the elemental composition of biological samples include Flame and Graphite Furnace Atomic Absorption Spectroscopy (F-AAS and GF-AAS), Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Each of these techniques has many advantages and limitations that should be considered in the first stage of planning the measurement procedure. Their reliability can be checked in the validation process and the precision, trueness and detection limits of elements belong to the most frequently determined validation parameters. The main purpose of this paper was the discussion of selected instrumental techniques (F-AAS, GF-AAS, ICP-OES and ICP-MS) in term of the achieved validation parameters and the usefulness in the analysis of biological samples. The focus in the detailed literature studies was also put on the methods of preparation of the biomedical samples. What is more based on the own data the usefulness of the total reflection X-ray fluorescence spectroscopy for the elemental analysis of animal tissues was examined. The detection limits of elements, precision and trueness for the technique were determined and compared with the literature data concerning other of the discussed techniques of elemental analysis. Reassuming, the following paper is to serve as a guide and comprehensive source of information concerning the validation parameters achievable in different instrumental techniques used for the elemental analysis of biomedical samples.

Synthesis and μ-Opioid Activity of the Primary Metabolites of Carfentanil.

Carfentanil is a synthetic opioid significantly more potent than clinically prescribed fentanyl. The primary metabolites of carfentanil, generated from human liver microsomes, were structurally confirmed through chemical synthesis. The synthesized compounds were evaluated for μ-opioid receptor (MOR) functional activity. Of the six metabolites assayed, a major metabolite showed comparable activity to the parent opioid. Three other metabolites showed significant MOR functional activity. The availability of the metabolites could aid improvements in the analysis of biomedical samples obtained from suspected human exposures to carfentanil and development of treatment protocols.

Synthesis of the Tripeptides Tyr-Thr-Lys Phosphorylated with Isopropyl Methyl- and (Deuteromethyl)phosphonochloridates as Reference Standards for the Analysis of Biomedical Samples

A procedure for the phosphorylation of the tripeptide Tyr-Thr-Lys with isopropyl methyl- or (deuteromethyl)phosphonochloridate is developed. The phosphorylated tripeptides are intended for use as reference standards in the analysis of blood samples of people suspected to have been exposed to acetylcholinesterase inhibitors. Conditions of hromatographic separation and purification of the synthesized compounds are determined and optimized, which ensures the preparation of high-purity phosphorylated tripeptides.

Focus on pre-processing step to ensure the clinical transferability of Raman data acquired on lymphocytes in different experimental and instrumental conditions

The efficiency of Raman spectroscopy for the analysis of biomedical samples has been largely demonstrated at the proof-of-concept stage during one-off measurement campaigns. However, bringing these results to the patient bedside requires to fill the gap for transferability of Raman data acquired in different experimental and instrumental conditions during multicentric measurement campaigns. In this study, we propose to evaluate a solution consisting in the application of Raman data preprocessing specifically developed to remove the spectral variability induced by such different conditions. For this purpose, we compared Raman data of lymphocytes acquired during two independent measurement campaigns from fresh unstained glass blood smears originating from healthy individuals and patients with a B-cell chronic lymphocytic leukemia (CLL) at an advanced stage. The differences between these campaigns were i) the instrumental configuration of the Raman devices, ii) the hospital partner, iii) the smear preparation method. A preprocessing developed previously and efficient for a specific measurement campaign is shown obsolete for these multicentric data. A second preprocessing based on Extended Multiplicative Signal Correction is able to homogenize the data by neutralizing the signal variability between the two measurement campaigns. These conclusions are drawn from the analysis of the data by Principal Component Analysis to study the source of variability between the two campaigns and by Partial Least Squares – Discriminant Analysis to assess the separability between healthy and CLL patients.

Adductomics: a promising tool for the verification of chemical warfare agents' exposures in biological samples.

Humans are constantly exposed to a wide range of reactive and toxic chemicals from the different sources in everyday life. Identification of the exposed chemical helps in the detection and understanding the exposure associated adverse health effects. Covalent adducts of proteins and DNA formed after xenobiotics exposure may serve as readily measurable indicators of these exposures. Measuring the exposed chemicals with focus on adducts resulting from the nucleophilic interactions with blood proteins is useful in the development of diagnostic markers. Particularly, the most abundant proteins such as albumin and hemoglobin acts as dominant scavengers for many reactive chemicals in blood and can serve as excellent diagnostic candidates to determine the type of chemical exposure. This review focuses on the potential application of an adductomics approach for the screening of bimolecular adducts of chemical warfare agents (CWAs). Recent incidents of CWAs use in Syria, Malaysia, and the UK illustrate the continuing threat of chemical warfare agents in the modern world. Detection of CWAs and their metabolites in blood or in other body fluids of victims depends on immediate access to victims. Concentrations of intact CWAs in body fluids of surviving victims may decline rapidly within a few days. Certain CWAs, particularly nerve agents and vesicants, form covalent bonds with certain amino acids to form CWA-protein adducts. Proteins that are abundant in the blood, including albumin and hemoglobin, may carry these adducts longer after the original exposure. We searched MEDLINE and ISI Web of Science databases using the key terms "adductomics" "adducts of CWAs," "CWAs adducts detection in the biological samples," "protein adducts of CWAs," alone and in combination with the keywords "detection" "intoxication" "exposure" "adverse effects" and "toxicity." We also included non-peer-reviewed sources such as text books, relevant newspaper reports, and applicable Internet resources. We screened bibliographies of identified articles for additional relevant studies including non-indexed reports. These searches produced 1931 citations of which only relevant and nonduplicate citations were considered for this review. The analysis of biomedical samples has several purposes including detecting and identifying the type of chemical agent exposed, understanding the biological mechanism, assists in giving adequate treatment, determining the cause of death and providing evidence in a court of justice for forensic investigations. Rapid advances in the mass spectrometry to acquire high-quality data with greater resolution enabled the analysis of protein and DNA adducts of xenobiotics including CWAs and place the rapidly advancing 'adductomics' next to the other "-omics" technologies. Adductomics can serve as a powerful bioanalytical tool for the verification of CWAs exposure. This review mostly describes the protein adducts for nerve agents and vesicants, outlines the procedures for measuring adducts, and suggests the evolving (or future) use of adducts in the detection and verification of CWAs.

Synthesis of O-tyrosine Phosphorylated Adducts of Methylphosphonic and Phosphoric Acid Derivatives as Reference Compounds for the Analysis of Biomedical Samples

Organophosphorus chemical agents are included in the 1st List of the Annex on Chemicals of the Convention on the Prohibition of the Development, Production, Stockpiling and Use of Chemical Weapons and on Their Destruction (Chemical Weapons Convention, CWC). For the purposes of verification of compliance with the provisions of the CWC, special methods, which are considered the most informative at determining the retrospective effects of organophosphorus toxicants on the body, are necessary. Typical long-lived biomarkers of organophosphate toxic agents are tyrosine phosphorylation products, the presence of which in biomedical samples clearly indicates the exposure to sarin, soman, tabun and V-series agents. We have elaborated methods for the synthesis and isolation of tyrosine adducts derivatives of methylphosphonic and phosphoric acids, used as reference samples. The synthesis scheme included the consecutive protection of carboxyl and amino groups of tyrosine, its O-phosphorylation by the corresponding alkylphosphonates and phosphates, the removal of protective groups with the release of corresponding O-phosphorylated tyrosine adducts. Their purification from im purities was carried out, using column chromatography (SiO2, eluent: dichloromethane/ethyl acetate 1:1). The purity of the obtained products was more than 90 %, so it was possible to involve them in further transformations with the use of catalyst without the threat of its «poisoning». Benzyl and carboxybenzyl protection of phosphorylated L-tyrosines (12–17) was removed by means of catalytic hydrogenation by molecular hydrogen under atmospheric pressure. Target adducts of phosphorylated reagents and L-tyrosin were obtained (63–82 %) in form of crystal white substances, readily soluble in water and ethanol, and poorly – in dichloromethane and acetonitrile

Advice on chemical weapons sample stability and storage provided by the Scientific Advisory Board of the Organisation for the Prohibition of Chemical Weapons to increase investigative capabilities worldwide

The Scientific Advisory Board (SAB) of the Organisation for the Prohibition of Chemical Weapons (OPCW) has provided advice on the long-term storage and stability of samples collected in the context of chemical weapons investigations. The information they compiled and reviewed is beneficial to all laboratories that carry out analysis of samples related to chemical warfare agents and is described herein. The preparation of this report was undertaken on request from the OPCW Director-General. The main degradation products for chemicals on the Schedules in the Annex on Chemicals of the Chemical Weapons Convention are tabulated. The expertise of the 25 scientists comprising the SAB, a review of the scientific literature on environmental and biomedical sample analysis, and answers to a questionnaire from chemists of nine OPCW Designated Laboratories, were drawn upon to provide the advice. Ten recommendations to ensure the long-term storage and stability of samples collected in relation to the potential use of chemical weapons were provided and are repeated here for the consideration of all laboratories worldwide.

Organisation for the Prohibition of Chemical Weapons' New Approaches to Laboratory Support for Control over Non-Proliferation

The development of scientific research methods and dual-use production technologies, the widening of the range of new toxic chemicals, as well as technical possibilities for the development of a new generation of poisonous substances, formally not forbidden by the acting Convention on the Prohibition of the Development, Production, Stockpiling and Use of Chemical Weapons and on their Destruction, pose a new level of threats to nonproliferation of chemical weapons. Under these circumstances, it is necessary to possess not only legal possibility, but also appropriate laboratory equipment and services for the effective non-proliferation control. Considerable attention in this sphere has been paid earlier to environmental samples for toxic chemicals analysis, including samples of air, soil, vegetation and water. But at the present time the Organisation for the Prohibition of Chemical Weapons (OPCW) gives special emphasis to analysis of biomedical samples (blood, urine) in the context of non-proliferation and investigations of alleged use of chemical weapons and toxic chemicals. The proper sensitivity during the detection and identification of biomarkers of exposure to chemical agents and toxic chemicals can be achieved by gas chromatography- mass spectrometry (GC/MS) and gas chromatography-tandem mass spectrometry (GC/MS/MS) methods. Efforts in this sphere are now focused on three main tasks – sample preparation, the optimization of the conditions of chromatographic separation of samples, storage and interpretation of mass-spectra characteristics. The article provides examples of how the above mentioned techniques are used in the detection of signs and evidence of exposure to organic phosphorus compounds and sulfur mustard

Accumulation of intact sulfur mustard in adipose tissue and toxicokinetics by chemical conversion and isotope-dilution liquid chromatography-tandem mass spectrometry.

Sulfur mustard (SM) is a powerful vesicant and one of the most harmful chemical warfare agents. Although having been studied for a long time, it is still difficult to fully elucidate the mechanisms of SM poisoning, and there is no effective antidote or specific treatment for SM injury. The investigations on toxicokinetics and tissue distribution of SM will help to understand its toxicity and provide a theoretical basis for pretreatment and therapy of SM poisoning. But the metabolic trajectory or fate of intact SM in vivo remains unclear, and there are insufficient experimental data to elucidate, due to its high reactivity and difficulty in biomedical sample analysis. In this paper, a sensitive method for the detection and quantification of intact SM in blood or tissues using isotope-dilution LC-MS/MS coupled with chemical conversion was developed. By transforming highly reactive SM into stable derivative product, the real concentration of intact SM in biological samples was obtained accurately. The toxicokinetics and tissue distribution studies of intact SM in rats were successfully profiled by the novel method after intravenous (10mg/kg) or cutaneous administration (1, 3 and 10mg/kg). The SM level in blood with peak time at 30-60min determined in cutaneous exposure experiment was found much higher than previously reported, and the mean residence time in blood extended to 1-1.5h. A significant accumulation of intact SM was observed in adipose tissues, including the perirenal fat, epididymal fat, subcutaneous fat and brown fat, in which the concentrations of SM were at least 15 times greater than those in non-adipose tissues in cutaneous exposed rats. The recovery of SM in body fat was calculated as 3.3% of bioavailable SM (the bioavailability after cutaneous exposure was evaluated as 16%). Thus, the adipose tissue was important for SM distribution and toxicity, which may pioneer a new model for both the prevention and treatment of SM exposure.

Solid-Phase Extraction of Sulfur Mustard Metabolites Using an Activated Carbon Fiber Sorbent.

A novel solid-phase extraction method using activated carbon fiber (ACF) was developed and validated. ACF has a vast network of pores of varying sizes and microporous structures that result in rapid adsorption and selective extraction of sulfur mustard metabolites according to the pH of eluting solvents. ACF could not only selectively extract thiodiglycol and 1-methylsulfinyl-2-[2-(methylthio)-ethylsulfonyl]ethane eluting a 9:1 ratio of dichloromethane to acetone, and 1,1'-sulfonylbis[2-(methylsulfinyl)ethane] and 1,1'-sulfonylbis- [2-S-(N-acetylcysteinyl)ethane] eluting 3% hydrogen chloride in methanol, but could also eliminate most interference without loss of analytes during the loading and washing steps. A sample preparation method has been optimized for the extraction of sulfur mustard metabolites from human urine using an ACF sorbent. The newly developed extraction method was applied to the trace analysis of metabolites of sulfur mustard in human urine matrices in a confidence-building exercise for the analysis of biomedical samples provided by the Organisation for the Prohibition of Chemical Weapons.

An improved method for retrospective quantification of sulfur mustard exposure by detection of its albumin adduct using ultra-high pressure liquid chromatography-tandem mass spectrometry.

Sulfur mustard (HD) adduct to human serum albumin (ALB) at Cys-34 residue has become an important and long-term retrospective biomarker of HD exposure. Here, a novel, sensitive, and convenient approach for retrospective quantification of HD concentration exposed to plasma was established by detection of the HD-ALB adduct using ultra-high pressure liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) with a novel non-isotope internal standard (IS). The HD-ALB adduct was isolated from HD-exposed plasma with blue Sepharose. The adduct was digested with proteinase K to form sulfur-hydroxyethylthioethyl ([S-HETE])-Cys-Pro-Phe tripeptide biomarker. The tripeptide adduct could be directly analyzed by UHPLC-MS/MS without an additional solid phase extraction (SPE), which was considered as a critical procedure in previous methods. The easily available 2-chloroethyl ethylsulfide (2-CEES) as HD surrogate was first reported to be used as IS in place of traditional d8-HD for quantification of HD exposure. Furthermore, 2-CEES was also confirmed to be a good IS alternative for quantification of HD exposure by investigation of product ion spectra for their corresponding tripeptide adducts which exhibited identical MS/MS fragmentation behaviors. The method was found to be linear between 1.00 and 250 ng•mL(-1) HD exposure (R(2)>0.9989) with precision of <4.50% relative standard deviation (%RSD), accuracy range between 96.5% and 114%, and a calculated limit of detection (LOD) of 0.532 ng•mL(-1). The lowest reportable limit (LRL) is 1.00 ng•mL(-1), over seven times lower than that of the previous method. The entire method required only 0.1 mL of plasma sample and took under 7 h without special sample preparation equipment. It is proven to be a sensitive, simple, and rugged method, which is easily applied in international laboratories to improve the capabilities for the analysis of biomedical samples related to verification of the Chemical Weapon Convention (CWC).

Non-Destructive Label-Free Monitoring of Drug Intake in Live Cells using ATR FT-IR Spectroscopy

Drug resistance is one of the major challenges in treatment of cancer. The study of the intake of drugs by cancer cells therefore is vital for elucidating the mechanism of drug resistance. Currently to quantify the intake of drugs involve destructive methods such as lysing the cell at each time point of analysis followed by UV-Vis or fluorescence measurements. With this approach, different batches of cell are used for each time point, increasing the biological variability, and it is not possible to perform further analysis on the same cell sample. Attenuated total reflection Fourier transform infrared (ATR FT-IR) is a promising non-destructive label-free while chemically specific technique for analysis of biomedical samples. In this work we demonstrated the quantification of drugs (e.g. doxorubicin), in situ, using the ATR FT-IR method to obtain the drug diffusion profile in the live cell. HeLa cells grown on a multi-bounce ATR crystal were treated with 20 micromolar of doxorubicin, a concentration level that is relevant to cancer studies, and FT-IR spectra were collected in a time course using a MCT detector. Quantification of doxorubicin in the cell was made using the signature peak at 1284 cm-1 showing the accumulation of the drug in cells as a function of time.The results from the ATR FT-IR measurements have shown that the doxorubicin concentration in the living cell increases from 0 to >50 micromolar after 2 hours of treatment demonstrating the partitioning effect of the drug in the cell. Furthermore, the cells also present a signature spectrum, which allows to follow the cell viability in parallel with the drug intake. This is a fast, cost-effective and chemically selective method which does not require sophisticated equipment and can be adapted easily.

Automated combustion accelerator mass spectrometry for the analysis of biomedical samples in the low attomole range.

The increasing role of accelerator mass spectrometry (AMS) in biomedical research necessitates modernization of the traditional sample handling process. AMS was originally developed and used for carbon dating, therefore focusing on a very high precision but with a comparably low sample throughput. Here, we describe the combination of automated sample combustion with an elemental analyzer (EA) online coupled to an AMS via a dedicated interface. This setup allows direct radiocarbon measurements for over 70 samples daily by AMS. No sample processing is required apart from the pipetting of the sample into a tin foil cup, which is placed in the carousel of the EA. In our system, up to 200 AMS analyses are performed automatically without the need for manual interventions. We present results on the direct total (14)C count measurements in <2 μL human plasma samples. The method shows linearity over a range of 0.65-821 mBq/mL, with a lower limit of quantification of 0.65 mBq/mL (corresponding to 0.67 amol for acetaminophen). At these extremely low levels of activity, it becomes important to quantify plasma specific carbon percentages. This carbon percentage is automatically generated upon combustion of a sample on the EA. Apparent advantages of the present approach include complete omission of sample preparation (reduced hands-on time) and fully automated sample analysis. These improvements clearly stimulate the standard incorporation of microtracer research in the drug development process. In combination with the particularly low sample volumes required and extreme sensitivity, AMS strongly improves its position as a bioanalysis method.

Improvements to the Fluoride Reactivation Method by Simple Organic Extraction for Retrospective Detection of Exposure to the Organophosphorus Nerve Agents in Human Plasma

A rapid and simple organic extraction method for the determination of the chemical warfare agent, isopropyl methylphosphonofluoridate (sarin, GB) in human plasma has been developed using gas chromatography-tandem mass spectrometry (GC-MS/MS). In the course of method development, several organic solvents have been screened and chloroform show a low background and increase signal to noise ratio of GB among other organic solvents. Especially, the organic extraction method of reactivated GB from the human plasma has a 30% greater recovery yield than solid-phase ex-traction (SPE). This simple extraction method was successfully applied to the trace analysis of nerve agents in human plasma in the 3rd Organisation for the Prohibition of Chemical Weapons (OPCW) confidence building exercise on biomedical sample analysis.

A New High Performance Liquid Chromatography Tandem Mass Spectrometric Method for Quantitative Determination of Soman-tyrosine Adduct in Exposed Rat Plasma

Towards the urgent need of accurately retrospective analysis of biomedical samples exposed by nerve agent soman( GD),we developed a new quantitative method of GD-tyrosine adduct( GD-Tyr) in exposed rat plasma by liquid chromatography( LC)-tandem mass spectrometry( MS/MS) with high sensitivity and high specificity.After a series of pretreatment procedures including extraction of albumin by affinity chromatography and ultrafiltration,enzymatic hydrolysis by pronase,and solid phase extraction,we qualitatively and quantitatively determined soman-tyrosine adduct by reversed-phase LC-triple quadrupole MS in the positive electrospray ionization and multiple reactions monitoring mode.The monitored transitions were m/z 260/214( GD-Tyr) and m/z 293/247( internal standard).A good linearity was obtained in the range of0.1-500 μg/L for GD-Tyr( R2=0.999) with a limit of detection of 0.02 μg/L and a limit of quantification of 0.05 μg/L.The recovery of GD-Tyr was in the range of 90.1%-103.5%,and the RSD of this method was less than 3%.We then investigated the toxicokinetics of GD-Tyr for GD exposed SD rat( n=5) in an intraperitoneal injection way.An obvious time and dose dependent relationship between GD-Tyr and the dose of soman was observed.We suggest that GD-tyrosine adduct can be used as an exposure biomarker to the retrospective detection of soman after exposure.

Signal Enhancement in Disperse Solutions for the Analysis of Biomedical Samples by Photothermal Spectroscopy

Photothermal lens spectrometry not only shows high sensitivity of colored heme protein determination, but also provides a change in the sensitivity compared to the theoretical values due to changes in the heat transfer in dispersed media. This can be used for estimating the size of disperse particles exemplified by hemoglobin cyanide, photothermal examination of the state of existence of hemoglobin in highly saline solutions by changes in photothermal properties upon dissociation of hemoglobin tetramers into dimers and monomers. The example of determination of contrast agents (dyes) in blood as the versification of the platform of photoacoustic/photothermal measurement of circulating blood volume is shown.

Distributed Medical Image Analysis and Diagnosis through Crowd-Sourced Games: A Malaria Case Study

In this work we investigate whether the innate visual recognition and learning capabilities of untrained humans can be used in conducting reliable microscopic analysis of biomedical samples toward diagnosis. For this purpose, we designed entertaining digital games that are interfaced with artificial learning and processing back-ends to demonstrate that in the case of binary medical diagnostics decisions (e.g., infected vs. uninfected), with the use of crowd-sourced games it is possible to approach the accuracy of medical experts in making such diagnoses. Specifically, using non-expert gamers we report diagnosis of malaria infected red blood cells with an accuracy that is within 1.25% of the diagnostics decisions made by a trained medical professional.