title: Gold nanoparticle chemiresistors operating in biological fluids.
abstract: Functionalised gold nanoparticle (Au(NP)) chemiresistors are investigated for direct sensing of small organic molecules in biological fluids. The principle reason that Au(NP) chemiresistors, and many other sensing devices, have limited operation in biological fluids is due to protein and lipid fouling deactivating the sensing mechanism. In order to extend the capability of such chemiresistor sensors to operate directly in biofluids, it is essential to minimise undesirable matrix effects due to protein and lipidic components. Ultrafiltration membranes were investigated as semi-permeable size-selective barriers to prevent large biomolecule interactions with Au(NP) chemiresistors operating in protein-loaded biofluids. All of the ultrafiltration membranes protected the Au(NP) chemiresistors from fouling by the globular biomolecules, with the 10 kDa molecular weight cut-off size being optimum for operation in biofluids. Titrations of toluene in different protein-loaded fluids indicated that small molecule detection was possible. A sensor array consisting of six different thiolate-functionalised Au(NP) chemiresistors protected with a size-selective ultrafiltration membrane successfully identified, and discriminated the spoilage of pasteurised bovine milk. This proof-of-principle study demonstrates the on-chip protein separation and small metabolite detection capability, illustrating the potential for this technology in the field of microbial metabolomics. Overall, these results demonstrate that a sensor array can be protected from protein fouling with the use of a membrane, significantly increasing the possible application areas of Au(NP) chemiresistors ranging from the food industry to health services.
authors: CSIRO, Materials Science and Engineering, Sydney, NSW 2070, Australia. lee.hubble@csiro.au
authors: Lee J
authors: LJ
authors: Hubble
authors: Edith
authors: E
authors: Chow
authors: James S
authors: JS
authors: Cooper
authors: Melissa
authors: M
authors: Webster
authors: Karl-Heinz
authors: KH
authors: Müller
authors: Lech
authors: L
authors: Wieczorek
authors: Burkhard
authors: B
authors: Raguse
mesh_terms: D000818:Animals; D001419:Bacteria / Q000378:metabolism; D002417:Cattle; D016002:Discriminant Analysis; D006046:Gold / Q000737:chemistry*; D008567:Membranes, Artificial; D055442:Metabolome; D053768:Metal Nanoparticles / Q000737:chemistry*; D008839:Microelectrodes; D008892:Milk / Q000737:chemistry*; D011506:Proteins / Q000737:chemistry / Q000302:isolation & purification; D013438:Sulfhydryl Compounds / Q000737:chemistry; D014050:Toluene / Q000737:chemistry / Q000302:isolation & purification; D014462:Ultrafiltration
chemical_list: D008567:Membranes, Artificial; D011506:Proteins; D013438:Sulfhydryl Compounds; D014050:Toluene; D006046:Gold