title: Non-invasive, in vitro analysis of islet insulin production enabled by an optical porous silicon biosensor.
abstract: A label-free porous silicon (pSi) based, optical biosensor, using both an antibody and aptamer bioreceptor motif has been developed for the detection of insulin. Two parallel biosensors were designed and optimised independently, based on each bioreceptor. Both bioreceptors were covalently attached to a thermally hydrosilylated pSi surface though amide coupling, with unreacted surface area rendered stable and low fouling by incorporation of PEG moieties. The insulin detection ability of each biosensor was determined using interferometric reflectance spectroscopy, using a range of different media both with and without serum. Sensing performance was compared in terms of response value, response time and limit of detection (LOD) for each platform. In order to demonstrate the capability of the best performing biosensor to detect insulin from real samples, an in vitro investigation with the aptamer-modified surface was performed. This biosensor was exposed to buffer conditioned by glucose-stimulated human islets, with the result showing a positive response and a high degree of selectivity towards insulin capture. The obtained results correlated well with the ELISA used in the clinic for assaying glucose-stimulated insulin release from donor islets. We anticipate that this type of sensor can be applied as a rapid point-of-use biosensor to assess the quality of donor islets in terms of their insulin production efficiency, prior to transplantation.
authors.affiliation: ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Future Industries Institute, University of South Australia, Mawson Lakes, South Australia 5095, Australia.
authors.forename: Rinku
authors.initials: R
authors.lastname: Chhasatia
authors.affiliation: Experimental Therapeutics Laboratory, Hanson Institute and Samson Institute, School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, SA 5000, Australia.
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Sweetman
authors.affiliation: ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Future Industries Institute, University of South Australia, Mawson Lakes, South Australia 5095, Australia.
authors.forename: Frances J
authors.initials: FJ
authors.lastname: Harding
authors.affiliation: St. Vincent's Institute of Medical Research, Victoria 3065, Australia.
authors.forename: Michaela
authors.initials: M
authors.lastname: Waibel
authors.affiliation: St. Vincent's Institute of Medical Research, Victoria 3065, Australia.
authors.forename: Tom
authors.initials: T
authors.lastname: Kay
authors.affiliation: St. Vincent's Institute of Medical Research, Victoria 3065, Australia.
authors.forename: Helen
authors.initials: H
authors.lastname: Thomas
authors.affiliation: St. Vincent's Institute of Medical Research, Victoria 3065, Australia.
authors.forename: Thomas
authors.initials: T
authors.lastname: Loudovaris
authors.affiliation: ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Future Industries Institute, University of South Australia, Mawson Lakes, South Australia 5095, Australia. Electronic address: nico.voelcker@unisa.edu.au.
authors.forename: Nicolas H
authors.initials: NH
authors.lastname: Voelcker
mesh_terms: D055910:Antibodies, Immobilized / Q000737:chemistry*; D052157:Aptamers, Nucleotide / Q000737:chemistry*; D001483:Base Sequence; D015374:Biosensing Techniques / Q000295:instrumentation*; D002478:Cells, Cultured; D005947:Glucose / Q000378:metabolism; D006801:Humans; D007328:Insulin / Q000032:analysis* / Q000378:metabolism; D007368:Interferometry / Q000295:instrumentation; D007515:Islets of Langerhans / Q000737:chemistry* / Q000378:metabolism; D057230:Limit of Detection; D055096:Optical Devices; D016062:Porosity; D012825:Silicon / Q000737:chemistry; D013057:Spectrum Analysis / Q000295:instrumentation
chemical_list: D055910:Antibodies, Immobilized; D052157:Aptamers, Nucleotide; D007328:Insulin; D005947:Glucose; D012825:Silicon
keywords: Aptamer; Insulin; Interferometric reflectance spectroscopy; Islet; Optical biosensor; Porous silicon