A paper based graphene-nanocauliflower hybrid composite for point of care biosensing

Abstract

Graphene paper has diverse applications in printed circuit board electronics, bioassays, 3D cell culture, and biosensing. Although development of nanometal-graphene hybrid composites is commonplace in the sensing literature, to date there are only a few examples of nanometal-decorated graphene paper for use in biosensing. In this manuscript, we demonstrate the synthesis and application of Pt nano cauliflower-functionalized graphene paper for use in electrochemical biosensing of small molecules (glucose, acetone, methanol) or detection of pathogenic bacteria (Escherichia coli O157:H7). Raman spectroscopy, scanning electron microscopy and energy dispersive spectroscopy were used to show that graphene oxide deposited on nanocellulose crystals was partially reduced by both thermal and chemical treatment. Fractal platinum nanostructures were formed on the reduced graphene oxide paper, producing a conductive paper with an extremely high electroactive surface area, confirmed by cyclic voltammetry and electrochemical impedance spectroscopy. To show the broad applicability of the material, the platinum surface was functionalized with three different biomaterials: 1) glucose oxidase (via chitosan encapsulation); 2) a DNA aptamer (via covalent linking), or 3) a chemosensory protein (via his linking). We demonstrate the application of this device for point of care biosensing. The detection limit for both glucose (0.08 ± 0.02 μM) and E. coli O157:H7 (1.3 ± 0.1 CFU mL-1) were competitive with, or superior to, previously reported devices in the biosensing literature. The response time (6 sec for glucose and 10 min for E. coli) were also similar to silicon biochip and commercial electrode sensors. The results demonstrate that the nanocellulose-graphene-nanoplatinum material is an excellent paper-based platform for development of electrochemical biosensors targeting small molecules or whole cells for use in point of care biosensing.

Novel impedimetric aptasensor for label-free detection of Escherichia coli O157:H7

“…The reported detection limit was 4.5 x 10 3 cfu•mL -1 . Recently, Burrs et al (Burrs et al 2016) have presented the development of platinum nanocauliflower-graphene hybrids on paper for amperometric detection of pathogenic E. coli O157:H7 using a RNA aptamer. However, the majority of the reported aptasensors require indirect methods that complicate the detection process.…”

Development of a disposable paper-based potentiometric immunosensor for real-time detection of a foodborne pathogen

“…Table S4.3 in Supporting Information compares the emerging methods in the literature -including other paper-based devices -for foodborne pathogens detection. Comparing with other electrochemical immunosensors (Altintas et al, 2018;Bhardwaj et al, 2017;Burrs et al, 2016;Khan et al, 2018) we can assume similar or higher time resolution of method, such as a higher range of quantification. Lower LOD values were attained with potentiometric aptamer resorting to the SWCNTs and graphene as ion-to-electron transducers (Hernández et al, 2014;Zelada-Guillén et al 2009 and nonporous gold modified platforms (Ranjbar et al, 2018), although this is the first time that such low LOD is reached for foodborne pathogens resorting to a potentiometric paper-based strip electrode.…”

Emerging Biorecognition and Transduction Schemes for Rapid Detection of Pathogenic Bacteria in Food

“…For example, a 64‐mer for capturing E. coli O157:H7 based on binding to the number of O‐antigens specific to O157:H7 lipopolysaccharides was used to develop an ELISA immunosensor with a LOD of 10 CFU/mL (no preconcentration) and a response time of 20 min (Lee and others ). Burrs and others () extended this concept and used the same aptamer to develop a disposable (<$4/assay) paper‐based electrochemical aptasensor for measuring E. coli O157:H7 in vegetable broth; the device had a LOD of 4 CFU/mL and a response time of 12 min with no preconcentration (10 min for incubation and 2 min for impedance measurement).…”

“…Science Foundation Nanobiosensors program (C. Gomes and E.S. McLamore; Grant No. 1511953/1512659-Nanobiosensing), and the Colombian funding agencies Colfuturo and Colciencias (D.C. Vanegas) for support.…”