Paper membrane-based SERS platform for the determination of glucose in blood samples

SULUDERE, ZEKIYE/0000-0002-1207-5814; Cetin, Demet/0000-0003-1186-4229WOS: 000362974100010PubMed: 26363778In this report, we present a paper membrane-based surface-enhanced Raman scattering (SERS) platform for the determination of blood glucose level using a nitrocellulose membrane as substrate paper, and the microfluidic channel was simply constructed by wax-printing method. The rod-shaped gold nanorod particles were modified with 4-mercaptophenylboronic acid (4-MBA) and 1-decanethiol (1-DT) molecules and used as embedded SERS probe for paper-based microfluidics. The SERS measurement area was simply constructed by dropping gold nanoparticles on nitrocellulose membrane, and the blood sample was dropped on the membrane hydrophilic channel. While the blood cells and proteins were held on nitrocellulose membrane, glucose molecules were moved through the channel toward the SERS measurement area. Scanning electron microscopy (SEM) was used to confirm the effective separation of blood matrix, and total analysis is completed in 5 min. In SERS measurements, the intensity of the band at 1070 cm(-1) which is attributed to B-OH vibration decreased depending on the rise in glucose concentration in the blood sample. The glucose concentration was found to be 5.43 +/- 0.51 mM in the reference blood sample by using a calibration equation, and the certified value for glucose was 6.17 +/- 0.11 mM. The recovery of the glucose in the reference blood sample was about 88 %. According to these results, the developed paper-based microfluidic SERS platform has been found to be suitable for use for the detection of glucose in blood samples without any pretreatment procedure. We believe that paper-based microfluidic systems may provide a wide field of usage for paper-based applications.Scientific and Technological Research Council of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [Cost MP 1205-111T983]The authors acknowledge The Scientific and Technological Research Council of Turkey (TUBITAK) with the project number Cost MP 1205-111T983 for funding

Glucose determination based on a two component self-assembled monolayer functionalized surfaceenhanced Raman spectroscopy (SERS) probe

Dudak, Fahriye Ceyda/0000-0003-4998-0460; Tamer, Ugur/0000-0001-9989-6123WOS: 000338438500022In this report, we present a new detection method for blood glucose, using gold nanorod SERS, a surface enhanced Raman scattering probe embedded in two component self-assembled monolayers (SAMs). Gold nanorod particles and a gold coated slide surface were modified with the two component SAMs consisting of 3-mercaptophenylboronic acid (3-MBA) and 1-decanethiol (1-DT). The immobilization of 3-MBA/1-DT surface-functionalized gold nanoparticles onto 3-MBA/1-DT modified gold-coated slide surfaces was achieved by the cooperation of hydrophobic forces. Two component SAM functionalized substrates were used as SERS probes, by means of the boronic acid and the alkyl spacer functional groups that serve as the molecular recognition and penetration agents, respectively. The SERS platform surface was characterized by cyclic voltammetry, contact angle measurements, AFM (atomic force microscopy) and Raman spectroscopy. Optimum values of the parameters such as pH, time and (3-MBA/1-DT) molar ratio were also examined for the glucose determination. The analytical performance was evaluated and linear calibration graphs were obtained in the glucose concentration range of 2-16 mM, which is also in the range of the blood glucose levels, and the detection limit was found to be 0.5 mM. As a result, the SERS platform was also used for the determination of glucose in plasma samples.Scientific and Technological Research Council of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [Cost MP 1205-111T983]The authors acknowledge The Scientific and Technological Research Council of Turkey (TUBITAK) with the project number Cost MP 1205-111T983 for funding. The authors would like to thank Prof. Nihal Aydogan and Hande Unsal (Hacettepe University, Department of Chemical Engineering, Turkey) for AFM measurements

Traumatic lung pathologies confused with COVID-19

While the COVID-19 pandemic affected the whole world, lung radiologic imaging has become widely used for diagnosis. Ground glass opacity is the most detected radiologic findings in pulmonary tomography. However, in the first 6-8 hours of CT scans of patients admitted to the hospital with injuries affecting the chest cavity, single or multiple patchy and/or diffuse ground-glass parenchymal infiltrates can be seen usually. Due to these appearances, it is necessary to eliminate COVID-19 in cases with a lung contusion. This study aims to evaluate the clinical and laboratory characteristics of patients who presented with pulmonary trauma and were suspected of COVID-19 due to lung images. Between the March 2020 and December 2020 pandemic period, patients who applied to our hospital in emergency services due to trauma and who were discharged or hospitalized in COVID services or followed in intensive care units because COVID-19 could not be excluded due to lung tomography findings were included in the study. It was evaluated retrospectively with laboratory tests and thoracic CTs in patients over 18 years old. Fourteen cases were included in the study, seven of them were males (50%), with a mean age of 45 (19-74). The COVID-19 PCR result was negative for all patients except one patient (case 11) with lymphopenia. Peripherally located ground-glass opacity (GGO) (92.9%), subpleural line (85.7%), air bronchogram (64.3%), pleural thickening (64.3%), atelectasis (% 64.3), consolidation (50%), ground glass mixed consolidation (42.9%) was detected in chest CT cases. Eleven cases (78.6%) were hospitalized to the COVID service or intensive care unit. Thoracic CT images of patients with lung trauma may be confused with COVID-19. It is appropriate to evaluate the cases together with epidemiological data, clinical and laboratory findings. Lymphopenia may help physicians to consider the diagnosis of COVID-19 in trauma patients. [Med-Science 2022; 11(2.000): 712-6

Immunomagnetic separation and Listeria monocytogenes detection with surfaceenhanced Raman scattering

Background/aim: We aimed to develop a rapid method to enumerate Listeria monocytogenes (L. monocytogenes) utilizing magnetic nanoparticle based preconcentration and surface-enhanced Raman spectroscopy measurements. Materials and methods: Biological activities of magnetic Au-nanoparticles have been observed to have the high biocompatibility, and a sample immunosensor model has been designed to use avidin attached Au-nanoparticles for L. monocytogenes detection. Staphylococcus aureus (S. aureus) and Salmonella typhimurium (S. typhimurium) bacteria cultures were chosen for control studies. Antimicrobial activity studies have been done to identify bio-compatibility and bio-characterization of the Au-nanoparticles in our previous study and capturing efficiencies to bacterial surfaces have been also investigated. Results: We constructed the calibration graphs in various population density of L. monocytogenes as 2.2 x 10(1) to 2.2 x 10(6) cfu/mL and the capture efficiency was found to be 75\%. After the optimization procedures, population density of L. monocytogenes and Raman signal intensity showed a good linear correlation (12 2 - 0.991) between 10(2) to 10(6) cfu/ml, L. monocylogenes. The presented sandwich assay provides low detection limits and limit of quantification as 12 cfu/mL and 37 cfu/mL, respectively. We also compared the experimental results with reference plate-counting methods and the practical utility of the proposed assay is demonstrated using milk samples. Conclusion: It is focused on the enumeration of L. monocytogenes in milk samples and the comparision of results of milk analysis obtained by the proposed SERS method and by plate counting method stay in food agreement. In the present study, all parameters were optimized to select SERS-based immunoassay method for L. monocytogenes bacteria to ensure LOD, selectivity, precision and repeatablity

Homozygosity mapping and targeted genomic sequencing reveal the gene responsible for cerebellar hypoplasia and quadrupedal locomotion in a consanguineous kindred

The biological basis for the development of the cerebro-cerebellar structures required for posture and gait in humans is poorly understood. We investigated a large consanguineous family from Turkey exhibiting an extremely rare phenotype associated with quadrupedal locomotion, mental retardation, and cerebro-cerebellar hypoplasia, linked to a 7.1-Mb region of homozygosity on chromosome 17p13.1–13.3. Diffusion weighted imaging and fiber tractography of the patients' brains revealed morphological abnormalities in the cerebellum and corpus callosum, in particular atrophy of superior, middle, and inferior peduncles of the cerebellum. Structural magnetic resonance imaging showed additional morphometric abnormalities in several cortical areas, including the corpus callosum, precentral gyrus, and Brodmann areas BA6, BA44, and BA45. Targeted sequencing of the entire homozygous region in three affected individuals and two obligate carriers uncovered a private missense mutation, WDR81 p.P856L, which cosegregated with the condition in the extended family. The mutation lies in a highly conserved region of WDR81, flanked by an N-terminal BEACH domain and C-terminal WD40 beta-propeller domains. WDR81 is predicted to be a transmembrane protein. It is highly expressed in the cerebellum and corpus callosum, in particular in the Purkinje cell layer of the cerebellum. WDR81 represents the third gene, after VLDLR and CA8, implicated in quadrupedal locomotion in humans