title: Lytic enzymes as selectivity means for label-free, microfluidic and impedimetric detection of whole-cell bacteria using ALD-Al2O3 passivated microelectrodes.
abstract: Point-of-care (PoC) diagnostics for bacterial detection offer tremendous prospects for public health care improvement. However, such tools require the complex combination of the following performances: rapidity, selectivity, sensitivity, miniaturization and affordability. To meet these specifications, this paper presents a new selectivity method involving lysostaphin together with a CMOS-compatible impedance sensor for genus-specific bacterial detection. The method enables the sample matrix to be directly flown on the polydopamine-covered sensor surface without any pre-treatment, and considerably reduces the background noise. Experimental proof-of-concept, explored by simulations and confirmed through a setup combining simultaneous optical and electrical real-time monitoring, illustrates the selective and capacitive detection of Staphylococcus epidermidis in synthetic urine also containing Enterococcus faecium. While providing capabilities for miniaturization and system integration thanks to CMOS compatibility, the sensors show a detection limit of ca. 10(8) (CFU/mL).min in a 1.5 μL microfluidic chamber with an additional setup time of 50 min. The potentials, advantages and limitations of the method are also discussed.
authors.affiliation: ICTEAM Institute, Université catholique de Louvain (UCL), Place du levant 3-L5.03.02, 1348 Louvain-la-Neuve, Belgium. Electronic address: numa.couniot@uclouvain.be.
authors.forename: N
authors.initials: N
authors.lastname: Couniot
authors.affiliation: ELI Institute Applied Microbiology (ELIM), Université catholique de Louvain (UCL), Croix du Sud 2-L7.05.12, 1348 Louvain-la-Neuve, Belgium.
authors.forename: T
authors.initials: T
authors.lastname: Vanzieleghem
authors.affiliation: ICTEAM Institute, Université catholique de Louvain (UCL), Place du levant 3-L5.03.02, 1348 Louvain-la-Neuve, Belgium.
authors.forename: J
authors.initials: J
authors.lastname: Rasson
authors.affiliation: ICTEAM Institute, Université catholique de Louvain (UCL), Place du levant 3-L5.03.02, 1348 Louvain-la-Neuve, Belgium.
authors.forename: N
authors.initials: N
authors.lastname: Van Overstraeten-Schlögel
authors.affiliation: ICTEAM Institute, Université catholique de Louvain (UCL), Place du levant 3-L5.03.02, 1348 Louvain-la-Neuve, Belgium.
authors.forename: O
authors.initials: O
authors.lastname: Poncelet
authors.affiliation: ELI Institute Applied Microbiology (ELIM), Université catholique de Louvain (UCL), Croix du Sud 2-L7.05.12, 1348 Louvain-la-Neuve, Belgium.
authors.forename: J
authors.initials: J
authors.lastname: Mahillon
authors.affiliation: ICTEAM Institute, Université catholique de Louvain (UCL), Place du levant 3-L5.03.02, 1348 Louvain-la-Neuve, Belgium.
authors.forename: L A
authors.initials: LA
authors.lastname: Francis
authors.affiliation: ICTEAM Institute, Université catholique de Louvain (UCL), Place du levant 3-L5.03.02, 1348 Louvain-la-Neuve, Belgium.
authors.forename: D
authors.initials: D
authors.lastname: Flandre
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry; D058491:Bacterial Load / Q000295:instrumentation* / Q000379:methods; D015374:Biosensing Techniques / Q000295:instrumentation; D058266:Dielectric Spectroscopy / Q000295:instrumentation*; D004595:Electroplating; D004867:Equipment Design; D019544:Equipment Failure Analysis; D056656:Lab-On-A-Chip Devices / Q000295:instrumentation*; D008839:Microelectrodes; D013194:Staining and Labeling / Q000379:methods; D013212:Staphylococcus epidermidis / Q000302:isolation & purification*; D013499:Surface Properties; D016482:Urinalysis / Q000295:instrumentation*
chemical_list: D000537:Aluminum Oxide
keywords: Impedance spectroscopy; Interdigitated microelectrodes; Lytic enzymes; Real-time capacitive biosensor; Urinary infections; Whole-cell bacteria