Parallel detection of multiple biomarkers in a point-of-care-competent device for the prediction of exacerbations in chronic inflammatory lung disease.

Sudden aggravations of chronic inflammatory airway diseases are difficult-to-foresee life-threatening episodes for which advanced prognosis-systems are highly desirable. Here we present an experimental chip-based fluidic system designed for the rapid and sensitive measurement of biomarkers prognostic for potentially imminent asthma or COPD exacerbations. As model biomarkers we chose three cytokines (interleukin-6, interleukin-8, tumor necrosis factor alpha), the bacterial infection marker C-reactive protein and the bacterial pathogen Streptococcus pneumoniae-all relevant factors in exacerbation episodes. Assay protocols established in laboratory environments were adapted to 3D-printed fluidic devices with emphasis on short processing times, low reagent consumption and a low limit of detection in order to enable the fluidic system to be used in point-of-care settings. The final device demonstrator was validated with patient sample material for its capability to detect endogenous as well as exogenous biomarkers in parallel.

Simple, Fast and Convenient Magnetic Bead-Based Sample Preparation for Detecting Viruses via Raman-Spectroscopy.

We introduce a magnetic bead-based sample preparation scheme for enabling the Raman spectroscopic differentiation of severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2)-positive and -negative samples. The beads were functionalized with the angiotensin-converting enzyme 2 (ACE2) receptor protein, which is used as a recognition element to selectively enrich SARS-CoV-2 on the surface of the magnetic beads. The subsequent Raman measurements directly enable discriminating SARS-CoV-2-positive and -negative samples. The proposed approach is also applicable for other virus species when the specific recognition element is exchanged. A series of Raman spectra were measured on three types of samples, namely SARS-CoV-2, Influenza A H1N1 virus and a negative control. For each sample type, eight independent replicates were considered. All of the spectra are dominated by the magnetic bead substrate and no obvious differences between the sample types are apparent. In order to address the subtle differences in the spectra, we calculated different correlation coefficients, namely the Pearson coefficient and the Normalized cross correlation coefficient. By comparing the correlation with the negative control, differentiating between SARS-CoV-2 and Influenza A virus is possible. This study provides a first step towards the detection and potential classification of different viruses with the use of conventional Raman spectroscopy.

Moving the Brazilian ischaemic stroke pathway to a value-based care: introduction of a risk-adjusted cost estimate model for stroke treatment.

The unsustainable increases in healthcare expenses and waste have motivated the migration of reimbursement strategies from volume to value. Value-based healthcare requires detailed comprehension of cost information at the patient level. This study introduces a clinical risk- and outcome-adjusted cost estimate model for stroke care sustained on time-driven activity-based costing (TDABC). In a cohort and multicentre study, a TDABC tool was developed to evaluate the costs per stroke patient, allowing us to identify and describe differences in cost by clinical risk at hospital arrival, treatment strategies and modified Rankin Score (mRS) at discharge. The clinical risk was confirmed by multivariate analysis and considered patients' National Institute for Health Stroke Scale and age. Descriptive cost analyses were conducted, followed by univariate and multivariate models to evaluate the risk levels, therapies and mRS stratification effect in costs. Then, the risk-adjusted cost estimate model for ischaemic stroke treatment was introduced. All the hospitals collected routine prospective data from consecutive patients admitted with ischaemic stroke diagnosis confirmed. A total of 822 patients were included. The median cost was I$2210 (interquartile range: I$1163-4504). Fifty percent of the patients registered a favourable outcome mRS (0-2), costing less at all risk levels, while patients with the worst mRS (5-6) registered higher costs. Those undergoing mechanical thrombectomy had an incremental cost for all three risk levels, but this difference was lower for high-risk patients. Estimated costs were compared to observed costs per risk group, and there were no significant differences in most groups, validating the risk and outcome-adjusted cost estimate model. By introducing a risk-adjusted cost estimate model, this study elucidates how healthcare delivery systems can generate local cost information to support value-based reimbursement strategies employing the data collection instruments and analysis developed in this study.

Dysphagia is a strong predictor of death and functional dependence at three months post-stroke / Disfagia é um forte preditor de morte e dependência funcional três meses após acidente vascular cerebral

ABSTRACT Background: Few Brazilian studies investigated risk factors for dysphagia and associated complications in a large cohort. Objective: To investigate frequency, predictors, and associated outcomes of dysphagia in patients up to three months post-stroke. Methods: Prospective cohort study of consecutively admitted patients in a specialized center for acute stroke. Patients with a transient ischemic attack, subarachnoid hemorrhage, cerebral venous thrombosis, hemorrhagic stroke with secondary cause, non-acute stroke, or those who did not consent to participate were excluded. Swallowing was evaluated by speech language pathologists using Volume-Viscosity Swallow Test. General function at three months post-stroke was assessed using the following instruments: Modified Rankin scale, Barthel Index and Functional Independence Measure. Results: A total of 831 patients were admitted and 305 patients were included according to the inclusion and exclusion criteria. The mean age of patients was 63.6±13.3 years, mean time from stroke to swallowing assessment was 4.2±4.1 days, and 45.2% of the patients had dysphagia. Age (OR=1.02; 95%CI 1.00-1.04; p=0.017), known medical history of obstructive sleep apnea (OR=5.13; 95%CI 1.74-15.15; p=0.003), and stroke severity at hospital admission (OR=1.10; 95%CI 1.06-1.15; p<0.001) were independently associated with dysphagia. Dysphagia (OR=3.78; 95%CI 2.16-6.61; p<0.001) and stroke severity (OR=1.05; 95%CI 1.00-1.09; p=0.024) were independently associated with death or functional dependence at three months. Conclusions: Dysphagia was present in almost half of stroke patients. Age, obstructive sleep apnea, and stroke severity were predictors of dysphagia, which was independently associated with death or functional dependence at three months.

RESUMO Antecedentes: Poucos estudos brasileiros investigaram fatores de risco para disfagia e suas complicações associadas em uma grande coorte. Objetivo: Investigar frequência, preditores e desfechos associados da disfagia em pacientes até três meses após acidente vascular cerebral (AVC). Métodos: Selecionamos pacientes admitidos consecutivamente em um centro especializado em AVC agudo. Excluímos pacientes com ataque isquêmico transitório, hemorragia subaracnóidea, trombose venosa cerebral, AVC hemorrágico de causa secundária, AVC não agudo ou aqueles que não consentiram em participar. A deglutição foi avaliada por fonoaudiólogos, por meio do teste de deglutição de volume-viscosidade. A função geral foi avaliada usando-se escala de Rankin modificada, índice de Barthel e medida de independência funcional. Resultados: Foram admitidos 831 pacientes e incluídos 305. A idade média foi 63,6±13,3 anos, o tempo médio da avaliação foi 4,2±4,1 dias e 45,2% apresentavam disfagia. Idade (razão de chances [OR] 1,02; intervalo de confiança [IC95%] 1,00-1,04; p=0,017), história médica conhecida de apneia obstrutiva do sono (OR=5,13; IC95% 1,74-15,15; p=0,003) e gravidade do AVC na admissão hospitalar (OR=1,10; IC95% 1,06-1,15; p<0,001) foram independentemente associados à disfagia. Disfagia (OR=3,78; IC95% 2,16-6,61; p<0,001) e gravidade do AVC (OR=1,05; IC95% 1,00-1,09; p=0,024) foram independentemente associadas com morte ou dependência funcional em três meses. Conclusões: A disfagia esteve presente em quase metade dos pacientes com AVC. Idade, apneia obstrutiva do sono e gravidade do AVC foram preditores de disfagia, que esteve independentemente associada com morte ou dependência funcional em três meses.

Dysphagia is a strong predictor of death and functional dependence at three months post-stroke.

BACKGROUND: Few Brazilian studies investigated risk factors for dysphagia and associated complications in a large cohort. OBJECTIVE: To investigate frequency, predictors, and associated outcomes of dysphagia in patients up to three months post-stroke. METHODS: Prospective cohort study of consecutively admitted patients in a specialized center for acute stroke. Patients with a transient ischemic attack, subarachnoid hemorrhage, cerebral venous thrombosis, hemorrhagic stroke with secondary cause, non-acute stroke, or those who did not consent to participate were excluded. Swallowing was evaluated by speech language pathologists using Volume-Viscosity Swallow Test. General function at three months post-stroke was assessed using the following instruments: Modified Rankin scale, Barthel Index and Functional Independence Measure. RESULTS: A total of 831 patients were admitted and 305 patients were included according to the inclusion and exclusion criteria. The mean age of patients was 63.6±13.3 years, mean time from stroke to swallowing assessment was 4.2±4.1 days, and 45.2% of the patients had dysphagia. Age (OR=1.02; 95%CI 1.00-1.04; p=0.017), known medical history of obstructive sleep apnea (OR=5.13; 95%CI 1.74-15.15; p=0.003), and stroke severity at hospital admission (OR=1.10; 95%CI 1.06-1.15; p<0.001) were independently associated with dysphagia. Dysphagia (OR=3.78; 95%CI 2.16-6.61; p<0.001) and stroke severity (OR=1.05; 95%CI 1.00-1.09; p=0.024) were independently associated with death or functional dependence at three months. CONCLUSIONS: Dysphagia was present in almost half of stroke patients. Age, obstructive sleep apnea, and stroke severity were predictors of dysphagia, which was independently associated with death or functional dependence at three months.

Isolation of pathogenic bacteria from sputum samples using a 3D-printed cartridge system.

Within this contribution we introduce a 3D-printed cartridge system enabling the convenient and cost-efficient sample preparation from sputum for subsequent PCR based detection schemes. The developed fluidic system operates on pneumatic actuations. The closed system ensures a very low probability for contamination during sample processing, which is crucial when using a highly sensitive detection method such as PCR. The enrichment of the bacterial cells is achieved using different types of amine-functionalized particles. Our particle-based sample preparation approach yields intact and viable bacterial cells. Accordingly, not only PCR-based detection schemes can be employed, but also spectroscopic methods and biochemical tests, which require cultivation steps, are possible. The cartridge design in principle is compatible with magnetic and non-magnetic particle types. We investigated both variants and found that the performance of expanded glass beads is superior over the magnetic particles within the cartridge. Owing to the rather large size of the expanded glass beads, the dimensions of the channels can be enlarged, leading to lower hydrodynamic resistances, which is beneficial when processing viscous samples such as sputum. We verified the performance of our system using both artificial and real sputum samples containing Escherichia coli and Moraxella catarrhalis.

Noise Sources and Requirements for Confocal Raman Spectrometers in Biosensor Applications.

Raman spectroscopy probes the biochemical composition of samples in a non-destructive, non-invasive and label-free fashion yielding specific information on a molecular level. Nevertheless, the Raman effect is very weak. The detection of all inelastically scattered photons with highest efficiency is therefore crucial as well as the identification of all noise sources present in the system. Here we provide a study for performance comparison and assessment of different spectrometers for confocal Raman spectroscopy in biosensor applications. A low-cost, home-built Raman spectrometer with a complementary metal-oxide-semiconductor (CMOS) camera, a middle price-class mini charge-coupled device (CCD) Raman spectrometer and a laboratory grade confocal Raman system with a deeply cooled CCD detector are compared. It is often overlooked that the sample itself is the most important "optical" component in a Raman spectrometer and its properties contribute most significantly to the signal-to-noise ratio. For this purpose, different representative samples: a crystalline silicon wafer, a polypropylene sample and E. coli bacteria were measured under similar conditions using the three confocal Raman spectrometers. We show that biosensor applications do not in every case profit from the most expensive equipment. Finally, a small Raman database of three different bacteria species is set up with the middle price-class mini CCD Raman spectrometer in order to demonstrate the potential of a compact setup for pathogen discrimination.

Simple and rapid peptide nanoprobe biosensor for the detection of Legionellaceae.

This study demonstrates the development of a sensitive, specific, and quantitative peptide-based nanoprobe prototype assay for the detection of Legionellaceae in a simple way and in a short time. In this work, proteases present in the culture supernatants of Legionella spp. were used as a biomarker. Fluorogenic peptide substrates, specific to Legionella strains culture supernatant proteases, were identified. Peptidases produced a significant increase in the fluorescence intensity following the cleavage of the dipeptide fluorogenic substrates. The specific substrates were identified and coupled with carboxyl-terminated nano-magnetic particles (NMPs). On the other hand, the C-terminal was conjugated with the cysteine residue to covalently integrate with a gold sensing platform via the Au-S linkage. Four different sensors were fabricated from the four specific substrates, which were treated with the protesase of six different species of Legionella. In the presence of specific protease, the peptide sequence is digested and the magnetic nanobeads moved out of the gold surface, resulting in the apparence of gold color. One of the nanoprobes sensitivity detects as low as 60 CFU mL-1 of Legionella anisa, Legionella micdadei, and Fluoribacter dumoffii. The cross-reactivity of the sensors was tested using other closely associated bacterial species and no significant cross-reactivity of the sensors was found. It is envisaged that this assay could be useful for screening purposes or might be supportive for the fast and easy detection of Legionella protease activity for water monitoring purposes.

Low-cost colorimetric diagnostic screening assay for methicillin resistant Staphylococcus aureus.

The timely diagnosis of MRSA in clinical samples helps to reduce the attendant morbidity/mortality associated with infection due to the organism. The early institution of appropriate therapy or deployment of infection control protocols are dependent on a timely report from the microbiology laboratory. Various assays currently used in the identification of MRSA are associated with inherent shortcomings, thus there is a need to explore newer diagnostic frontiers that can eliminate some of these short comings at a relatively cheap, timely, specific and sensitive manner. We present in this study a MRSA specific optical immunosensor to detect the presence of the pathogen on contaminated surface using control and patient strains. Results revealed a detection limits of 103 CFU mL-1 upon visual observation, and 29 CFU mL-1 as determined by the linear regression equation, following the use of ImageJ to quantify activated cotton swab color intensity. The specificity of the sensor was examined by blind testing a panel of non-MRSA bacteria (E. coli, S. aureus and S. epidermis). Negative visual read-out was observed for all tested non-specific bacteria except for MRSA. Assay takes an average of 5 min and presents a powerful point-of-care diagnostic platform for the detection of MRSA.

Aptasensor for the detection of Methicillin resistant Staphylococcus aureus on contaminated surfaces.

There is mounting evidence that contaminated hospital environment plays a crucial role in the transmission of nosocomial pathogens such as MRSA. The institution of infection control protocols is predicated on the early laboratory detection of the pathogen from relevant samples. Processing of environmental samples for the presence of bacterial contaminants in the clinical environment is poorly standardized when compared with analysis of clinical samples. The various laboratory methods available for processing environmental samples are difficult to standardized and most require a long turnaround time before results are available. In this study, we present a report of the performance of a novel pathogen aptasensor swab designed to qualitatively and quantitatively detect MRSA, on contaminated non-absorbable surfaces. The visual detection limit of the MRSA aptasensor swab was less than 100 CFU/ml and theoretically using a standard curve, was 2 CFU/ml. A relatively short turnaround time of 5 min was established for the assay while the linear range of quantitation was 102-105 CFU/ml. Engineered aptasensor targets MRSA selectively and binds to none of the other tested bacterial pathogen, on a multi-contaminated surface. This novel detection tool was easy to use and relatively cheap to produce.

Development of rapid colorimetric assay for the detection of Influenza A and B viruses.

The flu viruses are respiratory pathogens which, according to the World Health Organization (WHO), infect 5-10% of the world population resulting in 3-5 million cases of severe illness and 290,000 to 650,000 annual deaths. Early diagnosis and therapeutic intervention can ameliorate symptoms of infection and reduce mortality. The conventional diagnosis of viral infections, including flu viruses, has evolved over the years with diverse approaches, however, there are inherent short comings associated with these testing. There is an urgent need for rapid and low-cost diagnostic assays, due to the enormous annual burden of influenza diseases and its associated mortality. In this study, novel, low cost and easy to use colorimetric flu virus biosensor assay was developed. The sandwich assay format was utilized using antibodies immobilized onto cotton swabs, for the rapid detection of flu A and B viruses. These swabs serve as sample collection, analytes pre-concentration as well as sensing tool. The proof of concept was established for this assay in buffer and mucus samples. The limit of detection (LOD) of the colorimetric assay was 0.04 ng mL-1 for Flu A and Flu B respectively and with linear dynamic range between 0.04 ng ml-1 to 40 ng ml for both viruses in mucous samples. The assay can be performed at the patient's bed side by minimally skilled hospital personnel without the need for instrumentation. Cross-reactivity assays testing was done using Flu viruses specific activated swabs reacted with other common respiratory viral pathogens' antigen, in order to assess the specificity of the swabs.

Translation and Validation of the TOR-BSST© into Brazilian Portuguese for Adults with Stroke.

Brazil has a higher rate of dysphagia in stroke patients compared to developed countries, but does not have a fully validated method for early identification of dysphagia in this population. The aim of this study is to translate the TOR-BSST© into Brazilian Portuguese and assess the newly translated version for reliability and validity with Brazilian adult patients with stroke. The translation of the TOR-BSST© followed a multi-step process, according to the International Quality of Life Assessment project. For validation, we included patients with age ≥ 18 years and stroke diagnosis confirmed by neuroimaging and tolerance for videofluoroscopic swallowing assessment. The BR-PTfinal TOR-BSST© was administered by two trained screeners within two hours of videofluoroscopy. All assessors were independent and blinded. Estimates for reliability used the intraclass correlation coefficient (ICC) and for accuracy both sensitivity (SN) and negative predictive (NP) values were used, along with 95% confidence intervals (CI). Sixty patients were enrolled and tested for a mean (SD) of 14.4 (6.9) days from last seen normal. Of all the patients, 41 (68.3%) failed the BR-PTfinal TOR-BSST© and 21 (35%) were scored to have dysphagia on videofluoroscopy, of which 11 (52.4%) had mild dysphagia. The overall reliability between screeners was satisfactory (ICC = 0.59; 95% CI 0.32 to 0.76). The SN and NP values for the BR-PTfinal TOR-BSST© were 85.7% (95% CI 0.62-0.96) and 84.2% (95% CI 0.72-0.95), respectively. The TOR-BSST© was successfully translated to Brazilian Portuguese with the BR-PTfinal TOR-BSST© proven to have high sensitivity and negative predictive values when compared to gold standard videofluoroscopy.

Raman Signal Enhancement Tunable by Gold-Covered Porous Silicon Films with Different Morphology.

The ease of fabrication, large surface area, tunable pore size and morphology as well surface modification capabilities of a porous silicon (PSi) layer make it widely used for sensoric applications. The pore size of a PSi layer can be an important parameter when used as a matrix for creating surface-enhanced Raman scattering (SERS) surfaces. Here, we evaluated the SERS activity of PSi with pores ranging in size from meso to macro, the surface of which was coated with gold nanoparticles (Au NPs). We found that different pore diameters in the PSi layers provide different morphology of the gold coating, from an almost monolayer to 50 nm distance between nanoparticles. Methylene blue (MB) and 4-mercaptopyridine (4-MPy) were used to describe the SERS activity of obtained Au/PSi surfaces. The best Raman signal enhancement was shown when the internal diameter of torus-shaped Au NPs is around 35 nm. To understand the role of plasmonic resonances in the observed SERS spectrum, we performed electromagnetic simulations of Raman scattering intensity as a function of the internal diameter. The results of these simulations are consistent with the obtained experimental data.

Mapping the binding region of aptamer targeting small molecule: Dabigatran etexilate, an anti-coagulant.

Aptamers are single-stranded DNA or RNA, which have attracted considerable scientific interest due to their characteristic of specific and selective binding to target molecules. They are evolved from the in vitro process known as systematic evolution of ligands by exponential enrichment (SELEX). This paper reports a simple experimental approach to elucidate the binding region of small targets binding aptamers. A previously isolated 60-mer aptamer for the anti-coagulant dabigatran etexilate (DBG) was used for this investigation. Complimentary sequences labelled with a fluorophore and a quencher were used for testing the binding region by change in the fluorescence signal. The full-length aptamer was truncated to multiple shorter copies including a 38 nucleotides sequence that showed 47 fold high affinity compared to the original aptamer. Circular dichroism spectroscopy (CD) measurements indicate that the 38-mer is remarkably more sensitive than the parent aptamer. The truncated 38-mer sequence was used to construct a turn-on fluorescence sensor with the detection limit of 1 nM. The performance of the sensor was examined in blood serum samples and showed excellent recovery percentages exceeding 98%. The reported screening protocol could be applied to the growing small targets aptasensors that require efficient binding aptamer sequences coupled with optimum signal transduction methods.

Liquid-liquid extraction-assisted SERS-based determination of sulfamethoxazole in spiked human urine.

The determination of antibiotic levels in body fluids is of great importance in the field of personalized medicine and therapeutic drug monitoring. We report on the determination of sulfamethoxazole (SMX), an antibacterial drug of the sulfanilamide class, in spiked human urine. The protocol is based on the combination of surface-enhanced Raman spectroscopy (SERS) and liquid-liquid extraction (LLE-SERS analysis). First, the urine was diluted to reduce its buffer properties and the influence of the intrinsic urine components on the background SERS signal. Second, the acidification of the diluted urine and SMX extracts was performed to facilitate SMX extraction by chloroform and suppress the background signal, respectively. Finally, the SMX determination process was performed using hydroxylamine-stabilized silver nanoparticles as the SERS substrate. The efficiency and reliability of the LLE-SERS analysis were studied using spiked urine samples obtained from healthy volunteers with an SMX content within the therapeutically relevant concentration range (10-200 µg mL-1). Additionally, the verification of the analysis protocol was done using spiked urine samples obtained from oncology patients. The results of the verification demonstrate the applicability of the analysis for quantitative therapeutic drug monitoring due to the (i) strong suppression of the background SERS signal, which occurs as the result of LLE, dilution, and pH adjusting, (ii) satisfactory limit of detection of 1.7 µg mL-1, and (iii) simple, relatively fast (∼30 min), and cost-effective sample pretreatment.

Rapid detection of the aspergillosis biomarker triacetylfusarinine C using interference-enhanced Raman spectroscopy.

Triacetylfusarinine C (TAFC) is a siderophore produced by certain fungal species and might serve as a highly useful biomarker for the fast diagnosis of invasive aspergillosis. Due to its renal elimination, the biomarker is found in urine samples of patients suffering from Aspergillus infections. Accordingly, non-invasive diagnosis from this easily obtainable body fluid is possible. Within our contribution, we demonstrate how Raman microspectroscopy enables a sensitive and specific detection of TAFC. We characterized the TAFC iron complex and its iron-free form using conventional and interference-enhanced Raman spectroscopy (IERS) and compared the spectra with the related compound ferrioxamine B, which is produced by bacterial species. Even though IERS only offers a moderate enhancement of the Raman signal, the employment of respective substrates allowed lowering the detection limit to reach the clinically relevant range. The achieved limit of detection using IERS was 0.5 ng of TAFC, which is already well within the clinically relevant range. By using an extraction protocol, we were able to detect 1.4 µg/mL TAFC via IERS from urine within less than 3 h including sample preparation and data analysis. We could further show that TAFC and ferrioxamine B can be clearly distinguished by means of their Raman spectra even in very low concentrations.

Towards Raman spectroscopy of urine as screening tool.

For the screening purposes urine is an especially attractive biofluid, since it offers easy and noninvasive sample collection and provides a snapshot of the whole metabolic status of the organism, which may change under different pathological conditions. Raman spectroscopy (RS) has the potential to monitor these changes and utilize them for disease diagnostics. The current study utilizes mouse models aiming to compare the feasibility of the urine based RS combined with chemometrics for diagnosing kidney diseases directly influencing urine composition and respiratory tract diseases having no direct connection to urine formation. The diagnostic models for included diseases were built using principal component analysis with linear discriminant analysis and validated with a leave-one-mouse-out cross-validation approach. Considering kidney disorders, the accuracy of 100% was obtained in discrimination between sick and healthy mice, as well as between two different kidney diseases. For asthma and invasive pulmonary aspergillosis achieved accuracies were noticeably lower, being, respectively, 77.27% and 78.57%. In conclusion, our results suggest that RS of urine samples not only provides a solution for a rapid, sensitive and noninvasive diagnosis of kidney disorders, but also holds some promises for the screening of nonurinary tract diseases.

Nanobore fiber focus trap with enhanced tuning capabilities.

Confinement in fiber traps with two optical fibers facing one another relies on balancing the optical forces originating from the interaction of a scattering micro-object with the light beams delivered through the fibers. Here we demonstrate a novel type of dual fiber trap that involves the use of nanobore fibers, having a nano-channel located in the center of their fiber cores. This nano-element leads to a profound redistribution of the optical intensity and to considerably higher field gradients, yielding a trapping potential with greatly improved tuning properties compared to standard step-index fiber types. We evaluate the trap performance as a function of the fiber separation and find substantially higher stiffness for the nanobore fiber trap, especially in the range of short inter-fiber separations, while intermediate distances exhibit axial stiffness below that of the standard fiber. The results are in agreement with theoretical predictions and reveal that the exploitation of nanobore fibers allows for combinations of transverse and axial stiffness that cannot be accessed with common step-index fibers.

Rapid Isolation and Identification of Pneumonia-Associated Pathogens from Sputum Samples Combining an Innovative Sample Preparation Strategy and Array-Based Detection.

With this study, an innovative and convenient enrichment and detection strategy for eight clinically relevant pneumonia pathogens, namely, Acinetobacter baumannii, Escherichia coli, Haemophilus influenzae, Klebsiella pneumoniae, Moraxella catarrhalis, Pseudomonas aeruginosa, Staphylococcus aureus, and Streptococcus pneumoniae is introduced. Bacteria were isolated from sputum samples with amine-modified particles exploiting pH-dependent electrostatic interactions between bacteria and the functionalized particle surface. Following this, an asymmetric polymerase chain reaction as well as subsequent stringent array-based hybridization with specific complementary capture probes were performed. Finally, results were visualized by an enzyme-induced silver nanoparticle deposition, providing stable endpoint signals and consequently an easy detection possibility. The assay was optimized using spiked samples of artificial sputum with different strains of the abovementioned bacterial species. Furthermore, actual patient sputum samples with S. pneumoniae were successfully analyzed. The presented approach offers great potential for the urgent need of a fast, specific, and reliable isolation and identification platform for important pneumonia pathogens, covering the complete process chain from sample preparation up to array-based detection within only 4 h.