title: Paper-based α-amylase detector for point-of-care diagnostics.
abstract: We report the fabrication of a paper-sensor for quantitative detection of α-amylase activity in human blood serum. Pieces of filter papers were coated with starch-iodine solution leading to an intense blue coloration on the surface. Dispensing α-amylase solution on the starch-iodine coated paper reduced the intensity of the color because of starch-hydrolysis catalyzed by amylase. The variation in the intensity of the color with the concentration of amylase was estimated in three stages: (i) initially, the paper-surface was illuminated with a light emitting diode, (ii) then, the transmitted (reflected) rays emitted through (from) the paper were collected on a photoresistor, and (iii) the variations in the electrical resistance of the photoresistor were correlated with the amylase concentration in analyte. The resistance of photoresistor decreased monotonically with an increase in amylase concentration because the intensity of the reflected (transmitted) rays collected from (through) the paper increased with reduction in the color intensity on the paper surface. Since a specific bio-reaction was employed to detect the activity of amylase, the sensor was found to be equally efficient in detecting unknown quantities of amylase in human blood serum. The reported sensor has shown the potential to graduate into a point-of-care detection tool for α-amylase.
authors.affiliation: Department of Chemical Engineering, Indian Institute of Technology, Guwahati, Assam 781039, India.
authors.forename: Satarupa
authors.initials: S
authors.lastname: Dutta
authors.affiliation: Centre for Nanotechnology, Indian Institute of Technology, Guwahati, Assam 781039, India.
authors.forename: Nilanjan
authors.initials: N
authors.lastname: Mandal
authors.affiliation: Department of Chemical Engineering, Indian Institute of Technology, Guwahati, Assam 781039, India; Centre for Nanotechnology, Indian Institute of Technology, Guwahati, Assam 781039, India. Electronic address: dipban@iitg.ernet.in.
authors.forename: Dipankar
authors.initials: D
authors.lastname: Bandyopadhyay
mesh_terms: D015374:Biosensing Techniques; D006801:Humans; D006868:Hydrolysis; D010209:Paper; D019095:Point-of-Care Systems; D013213:Starch / Q000031:analogs & derivatives / Q000737:chemistry; D000516:alpha-Amylases / Q000097:blood* / Q000737:chemistry
chemical_list: C055509:iodinated starch; D013213:Starch; D000516:alpha-Amylases
keywords: Amylase; Bio-sensor; Diagnostic tool; Paper; Photoresistor; Point-of-care device