Severity: Warning
Message: file_get_contents(https://...@gmail.com&api_key=61f08fa0b96a73de8c900d749fcb997acc09): Failed to open stream: HTTP request failed! HTTP/1.1 429 Too Many Requests
Filename: helpers/my_audit_helper.php
Line Number: 143
Backtrace:
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 143
Function: file_get_contents
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 209
Function: simplexml_load_file_from_url
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 3098
Function: getPubMedXML
File: /var/www/html/application/controllers/Detail.php
Line: 574
Function: pubMedSearch_Global
File: /var/www/html/application/controllers/Detail.php
Line: 488
Function: pubMedGetRelatedKeyword
File: /var/www/html/index.php
Line: 316
Function: require_once
Severity: Warning
Message: Attempt to read property "Count" on bool
Filename: helpers/my_audit_helper.php
Line Number: 3100
Backtrace:
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 3100
Function: _error_handler
File: /var/www/html/application/controllers/Detail.php
Line: 574
Function: pubMedSearch_Global
File: /var/www/html/application/controllers/Detail.php
Line: 488
Function: pubMedGetRelatedKeyword
File: /var/www/html/index.php
Line: 316
Function: require_once
The use of nucleic acid tests (NAT) for sensitive and rapid detection of pathogens relevant to human health has increased due to the ubiquity of nucleic acid amplification techniques such as polymerase chain reaction. The use of such tools for detection of amplified nucleic acid (NA) in field and clinical settings is limited by the need for complex instrumentation and trained users. To address these limitations we developed a rapid, robust, and instrument-free colorimetric detection method for nucleic acids using a visible region dye, Nile Blue (NB). NB is a cationic benzophenoxazine dye with well-known binding interactions with NA and has been used in instrumental methods for DNA quantification. When combined with dsDNA, the color of NB shifts from blue to purple. Images of this color shift are collected and are subjected to image analysis. Observed changes in the red and green colorimetric intensities are linked to the ratio of dsDNA to NB. By titrating solutions of dsDNA against a series of NB concentrations, we found it possible to quantitate dsDNA at concentrations ranging from 10-100 μg mL using a -means cluster analysis method. This range is comparable to that of NA concentrations quantified using gold-standard UV-Visible spectroscopy and to the concentrations of NA in biological samples after amplification. Unknown concentrations of dsDNA from yeast extracts were correctly identified within ±5 μg mL of true concentration. Preliminary experiments demonstrate use of the developed NB method on paper-based analytical devices. As an instrument-free detection method, NB allows for rapid and robust quantification of dsDNA in field settings.
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Source |
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http://dx.doi.org/10.1039/d1ay01598b | DOI Listing |
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