Ellipsometric measurement of skin refractive index in vivo

Vegetable tars are newly formed resinous products extracted by pyrolysis from wood or bark. Since prehistoric times, they have been used for their adhesive, water-repellent, repellent and finally medicinal properties. This work investigated the use of these vegetable tars as sources of bio-fungicides. The physicochemical properties of the tars obtained in the labor-atories showed a significant yield of 1.22%, 0.66% and 0.51% respectively for the wood of (Jeniperus phoenicea, Olea europeae sylvestris and Acacia torti-lis Sub raddiana). They also showed a density value of 1.22 and a refractive index of about 1.5115 for J.phoenicea, an acid number of 0.39 and a dry matter ratio of 19.86% for A. tortilis Sub raddiana. Considerable antifungal activity of the acetate of three tars against certain fungal phytopathogens (Fusarium) was observed with the most remarkable MIC values ranging from 0.1 mg / ml to 0.46 mg / ml. The J. phoenicea extracts were more active against F. oxysporum f sp albedinis (FOA) strains. The growth of F. solani was more sensitive to acetate extracts from O. europeae. Dichloromethane ex-tracts of A. tortilis Sub raddiana yielded with an average MIC of 0.16 and 1.02 mg / ml, respectively for strains of F. oxysporum and F. graminearum. The bioautography test revealed the presence of 3 antifusaric molecules of interest. These MIC results further merit in vivo tests for the development of future biofungicides.

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Etched Fiber Bragg Grating Biosensor Functionalized with Aptamers for Detection of Thrombin

Sensors ◽

10.3390/s18124298 ◽

2018 ◽

Vol 18 (12) ◽

pp. 4298 ◽

Cited By ~ 21

Author(s):

Aliya Bekmurzayeva ◽

Kanat Dukenbayev ◽

Madina Shaimerdenova ◽

Ildar Bekniyazov ◽

Takhmina Ayupova ◽

...

Keyword(s):

Refractive Index ◽

Fiber Bragg Grating ◽

Chemical Vapor ◽

Bragg Grating ◽

Clinical Settings ◽

Long Period Grating ◽

Bragg Wavelength ◽

Sensing System ◽

Index Unit

A biosensor based on an etched Fiber Bragg Grating (EFBG) for thrombin detection is reported. The sensing system is based on a Fiber Bragg Grating (FBG) with a Bragg wavelength of 1550 nm, wet-etched in hydrofluoric acid (HF) for ~27 min, to achieve sensitivity to a refractive index (RI) of 17.4 nm/RIU (refractive index unit). Subsequently, in order to perform a selective detection of thrombin, the EFBG has been functionalized with silane-coupling agent 3-(aminopropyl)triethoxysilane (APTES) and a cross-linker, glutaraldehyde, for the immobilization of thrombin-binding aptamer. The biosensor has been validated for thrombin detection in concentrations ranging from 10 nM to 80 nM. The proposed sensor presents advantages with respect to other sensor configurations, based on plasmonic resonant tilted FBG or Long Period Grating (LPG), for thrombin detection. Firstly, fabricating an EFBG only requires chemical etching. Moreover, the functionalization method used in this study (silanization) allows the avoidance of complicated and expensive fabrications, such as thin film sputtering or chemical vapor deposition. Due to their characteristics, EFBG sensors are easier to multiplex and can be used in vivo. This opens new possibilities for the detection of thrombin in clinical settings.

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