title: A paper strip based non-invasive glucose biosensor for salivary analysis.
abstract: In our present study, we developed an optical biosensor for direct determination of salivary glucose by using immobilized glucose oxidase enzyme on filter paper strip (specific activity 1.4 U/strip) and then reacting it with synthetic glucose samples in presence of co-immobilized color pH indicator. The filter paper changed color based on concentration of glucose in reaction media and hence, by scanning this color change (using RGB profiling) through an office scanner and open source image processing software (GIMP) the concentration of glucose in the reaction medium could be deduced. Once the biosensor was standardized, the synthetic glucose sample was replaced with human saliva from donors. The individual's blood glucose level at the time of obtaining saliva was also measured using an Accuchek(™) active glucometer (Roche Inc.). In this preliminary study, a correlation of nearly 0.64 was found between glucose levels in saliva and blood of healthy individuals and in diabetic patients it was nearly in the order of 0.95, thereby validating the importance of salivary analysis. The RGB profiling method obtained a detection range of 9-1350 mg/dL glucose at a response time of 45 s and LOD of 22.2 mg/dL.
authors.affiliation: Centre for Biomedical Engineering, Indian Institute of Technology Delhi, New Delhi 110016, India.
authors.forename: Anuradha
authors.initials: A
authors.lastname: Soni
authors.affiliation: Centre for Biomedical Engineering, Indian Institute of Technology Delhi, New Delhi 110016, India. Electronic address: sandeepjha@cbme.iitd.ac.in.
authors.forename: Sandeep Kumar
authors.initials: SK
authors.lastname: Jha
mesh_terms: D015374:Biosensing Techniques; D001786:Blood Glucose; D003920:Diabetes Mellitus; D004800:Enzymes, Immobilized / Q000737:chemistry; D005947:Glucose / Q000737:chemistry / Q000302:isolation & purification*; D005949:Glucose Oxidase / Q000737:chemistry; D006801:Humans; D010209:Paper; D012463:Saliva / Q000737:chemistry*
chemical_list: D001786:Blood Glucose; D004800:Enzymes, Immobilized; D005949:Glucose Oxidase; D005947:Glucose
keywords: Glucose biosensor; Non-invasive biosensor; Paper strip immobilization; Saliva glucose; Smartphone based biosensor