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Billeberga, Sweden

Liu Y.,Lund University | Chen D.,Lund University | Fan X.,Lund University | Mattiasson B.,Lund University | Mattiasson B.,CapSenze HB
Biosensors and Bioelectronics | Year: 2014

To meet urgent needs for solving serious worldwide drug-resistance problems, a sensitive label-free capacitive sensor developed in our group was investigated as a tool to be applied in the field of antibiotic resistance genotyping, for instance the detection of ampicillin resistance gene (ampR). Proof-of-concept data demonstrated its detection sensitivity of pico-molar without any signal amplification step and a dynamic range of at least three orders of magnitude. The detection limits of less than 1. pM for the single-stranded ampR oligonucleotide and 4. pM for the double-stranded target can reliably be achieved after only 2.5. min sample reaction. Reusability of the probe-functionalized disposable electrode was investigated by comparing different regeneration solutions; mix of 25. mM NaOH/30% formamide was employed to regenerate the electrode for at least six cycles without significant loss of sensing ability. Assay is performed automatically and result is retrieved in 20. min. The developed sensitive genotyping tool is expected to provide simple, fast and affordable screening for monitoring spread of antibiotic resistances, which is suitable for testing in field setting. © 2014 Elsevier B.V. Source

Lebogang L.,Lund University | Hedstrom M.,Lund University | Mattiasson B.,Lund University | Mattiasson B.,CapSenze HB
Analytica Chimica Acta | Year: 2014

The harmful effects of cyanotoxins in surface waters have led to increasing demands for accurate early warning methods. This study proposes a capacitive immunosensor for broad-spectrum detection of the group of toxic cyclic peptides called microcystins (~80 congeners) at very low concentration levels. The novel analytical platform offers significant advances compared to the existing methods. Monoclonal antibodies (mAbs, clone AD4G2) that recognize a common element of microcystins were used to construct the biosensing layer. Initially, a stable insulating anchor layer for the mAbs was made by electropolymerization of tyramine onto a gold electrode surface, with subsequent incorporation of gold nanoparticles (AuNPs) on the glutaraldehyde (5%) activated polytyramine surface. The biosensor responded linearly to microcystin concentrations from 1×10-13M to 1×10-10M MC-LR standard with a limit of detection of 2.1×10-14M. The stability of the biosensor was evaluated by repeated measurements of the antigen and by determining the capacitance change relative to the original response, which decreased below 90% after the 30th cycle. © 2014 Elsevier B.V. Source

Gutierrez R A.V.,Lund University | Gutierrez R A.V.,Higher University of San Andres | Hedstrom M.,Lund University | Hedstrom M.,CapSenze HB | And 2 more authors.
Biotechnology Reports | Year: 2015

A capacitive biosensor was used for detection of aflatoxin B1. Two different methods for cleaning gold electrodes were evaluated using cyclic voltammetry in the presence of ferricyanide as redox couple. The methods involve use of a sequence of cleaning steps avoiding the use of Piranha solution and plasma cleaner. Anti-aflatoxin B1 was immobilized on self-assembled monolayers (SAM). The immune-capacitive biosensor is able to detect aflatoxin B1 concentrations in a linear range of 3.2 × 10-12 M to 3.2 × 10-9 M when thiourea was used to form the SAM; 3.2 × 10-9 M to 3.2 × 10-7 M when thioctic acid was used. When the gold surface was isolated with tyramine-electropolymerization linear ranges of 3.2 × 10-13 M to 3.2 × 10-7 M and 3.2 × 10-9 M to 3.2 × 10-7 M where obtained, respectively. The results obtained show the difference in linear range, limit of detection, and limit of quantification when different self-assembled monolayers are used for aflatoxin B1 detection. © 2015 The Author. Source

Erturk G.,Lund University | Erturk G.,Hacettepe University | Berillo D.,Lund University | Hedstrom M.,Lund University | And 3 more authors.
Biotechnology Reports | Year: 2014

An analytical method is presented, combining novel microcontact imprinting technique and capacitive biosensor technology for the detection of BSA. Glass cover slips were used for preparation of protein stamps. The microcontact-BSA imprinted gold electrodes were prepared in the presence of methacrylic acid (MAA) and poly-ethylene glycol dimethacrylate (PEGDMA) as the cross-linker by bringing the protein stamp and the gold electrode into contact under UV-polymerization. Real-time BSA detection studies were performed in the concentration range of 1.0 × 10-20-1.0 × 10-8 M with a limit of detection (LOD) of 1.0 × 10-19 M. Cross-reactivity towards HSA and IgG were 5 and 3%, respectively. The electrodes were used for >70 assays during 2 months and retained their binding properties during all that time. The NIP (non-imprinted) electrode was used as a reference. The microcontact imprinting technology combined with the biosensor applications is a promising technology for future applications. © 2014 The Authors. Source

Erturk G.,Lund University | Erturk G.,Hacettepe University | Hedstrom M.,Lund University | Hedstrom M.,CapSenze HB | And 4 more authors.
Analytica Chimica Acta | Year: 2015

Prostate specific antigen (PSA) is a valuable biomarker for early detection of prostate cancer, the third most common cancer in men. Ultrasensitive detection of PSA is crucial to screen the prostate cancer in an early stage and to detect the recurrence of the disease after treatment. In this report, microcontact-PSA imprinted (PSA-MIP) capacitive biosensor chip was developed for real-time, highly sensitive and selective detection of PSA. PSA-MIP electrodes were prepared in the presence of methacrylic acid (MAA) as the functional monomer and ethylene glycol dimethacrylate (EGDMA) as the cross-linker via UV polymerization. Immobilized Anti-PSA antibodies on electrodes (Anti-PSA) for capacitance measurements were also prepared to compare the detection performances of both methods. The electrodes were characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM) and cyclic voltammetry (CV) and real-time PSA detection was performed with standard PSA solutions in the concentration range of 10 fg mL-1-100 ng mL-1. The detection limits were found as 8.0 × 10-5 ng mL-1 (16 × 10-17 M) and 6.0 × 10-4 ng mL-1 (12 × 10-16 M) for PSA-MIP and Anti-PSA electrodes, respectively. Selectivity studies were performed against HSA and IgG and selectivity coefficients were calculated. PSA detection was also carried out from diluted human serum samples and finally, reproducibility of the electrodes was tested. The results are promising and show that when the sensitivity of the capacitive system is combined with the selectivity and reproducibility of the microcontact-imprinting procedure, the resulting system might be used successfully for real-time detection of various analytes even in very low concentrations. © 2015 Elsevier B.V. Source

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