{"entity": "researcher", "timestamp": "2026-07-22T17:37:32.926Z", "family": "Xu", "given": "Xingxing", "initials": "X", "orcid": "0000-0002-1769-4382", "affiliations": ["Division of Solid-State Electronics, Department of Engineering Sciences, \u00c5ngstr\u00f6m Laboratory , Uppsala University , P.O. Box 534, SE-751 21 Uppsala , Sweden."], "links": {"self": {"href": "https://publications.scilifelab.se/researcher/c0585b665e994ac5990b4911b0cc5cfa.json"}, "display": {"href": "https://publications.scilifelab.se/researcher/c0585b665e994ac5990b4911b0cc5cfa"}}, "publications": [{"entity": "publication", "iuid": "7aa9a011dfae4264bb5ed7dbf3b4c135", "links": {"self": {"href": "https://publications.scilifelab.se/publication/7aa9a011dfae4264bb5ed7dbf3b4c135.json"}, "display": {"href": "https://publications.scilifelab.se/publication/7aa9a011dfae4264bb5ed7dbf3b4c135"}}, "title": "Estimating Detection Limits of Potentiometric DNA Sensors Using Surface Plasmon Resonance Analyses.", "authors": [{"family": "Xu", "given": "Xingxing", "initials": "X", "orcid": "0000-0002-1769-4382", "researcher": {"href": "https://publications.scilifelab.se/researcher/c0585b665e994ac5990b4911b0cc5cfa.json"}}, {"family": "Makaraviciute", "given": "Asta", "initials": "A"}, {"family": "Abdurakhmanov", "given": "Eldar", "initials": "E"}, {"family": "Wermeling", "given": "Fredrik", "initials": "F"}, {"family": "Li", "given": "Shiyu", "initials": "S", "orcid": "0000-0003-4948-8353", "researcher": {"href": "https://publications.scilifelab.se/researcher/eaafe0529dbc46fb904b20cb943dad09.json"}}, {"family": "Danielson", "given": "U Helena", "initials": "UH", "orcid": "0000-0003-2728-0340", "researcher": {"href": "https://publications.scilifelab.se/researcher/b2bf7dffedf44237807c23718c72efa6.json"}}, {"family": "Nyholm", "given": "Leif", "initials": "L", "orcid": "0000-0001-9292-016X", "researcher": {"href": "https://publications.scilifelab.se/researcher/b7be3793cb034f04a7303a3ba8d0d4bf.json"}}, {"family": "Zhang", "given": "Zhen", "initials": "Z", "orcid": "0000-0003-4317-9701", "researcher": {"href": "https://publications.scilifelab.se/researcher/b84c807f13484a2abf4ab92ab77e37ec.json"}}], "type": "journal article", "published": "2020-01-24", "journal": {"title": "ACS Sens.", "issn": "2379-3694", "issn-l": "2379-3694", "volume": "5", "issue": "1", "pages": "217-224"}, "abstract": "As the signals of potentiometric-based DNA ion-selective field effect transistor (ISFET) sensors differ largely from report to report, a systematic revisit to this method is needed. Herein, the hybridization of the target and the probe DNA on the sensor surface and its dependence on the surface probe DNA coverage and the ionic strength were systematically investigated by surface plasmon resonance (SPR). The maximum potentiometric DNA hybridization signal that could be registered by an ISFET sensor was estimated based on the SPR measurements, without considering buffering effects from any side interaction on the sensing electrode. We found that under physiological solutions (200 to 300 mM ionic strength), the ISFET sensor could not register the DNA hybridization events on the sensor surface due to Debye screening. Lowering the salt concentration to enlarge the Debye length would at the same time reduce the surface hybridization efficiency, thus suppressing the signal. This adverse effect of low salt concentration on the hybridization efficiency was also found to be more significant on the surface with higher probe coverage due to steric hindrance. With the method of diluting buffer, the maximum potentiometric signal generated by the DNA hybridization was estimated to be only around 120 mV with the lowest detection limit of 30 nM, occurring on a surface with optimized probe coverage and in the tris buffer with 10 mM NaCl. An alternative method would be to achieve high-efficiency hybridization in the buffer with high salt concentration (1 M NaCl) and then to perform potentiometric measurements in the buffer with low salt concentration (1 mM NaCl). Based on the characterization of the stability of the hybridized DNA duplexes on the sensor surface in low salt concentration buffer solutions, the estimated maximum potentiometric signal could be significantly higher using the alternative method. The lowest detection limit for this alternative method was estimated to be around 0.6 nM. This work can serve as an important quantitative reference for potentiometric DNA sensors.", "doi": "10.1021/acssensors.9b02086", "pmid": "31833355", "labels": {"Drug Discovery and Development": "Technology development"}, "xrefs": [], "notes": [], "created": "2020-01-07T13:59:48.906Z", "modified": "2025-10-17T13:05:08.079Z"}, {"entity": "publication", "iuid": "8ccac0ee2a5541a0a004b8a69d5dc52d", "links": {"self": {"href": "https://publications.scilifelab.se/publication/8ccac0ee2a5541a0a004b8a69d5dc52d.json"}, "display": {"href": "https://publications.scilifelab.se/publication/8ccac0ee2a5541a0a004b8a69d5dc52d"}}, "title": "Structural Changes of Mercaptohexanol Self-Assembled Monolayers on Gold and Their Influence on Impedimetric Aptamer Sensors.", "authors": [{"family": "Xu", "given": "Xingxing", "initials": "X", "orcid": "0000-0002-1769-4382", "researcher": {"href": "https://publications.scilifelab.se/researcher/c0585b665e994ac5990b4911b0cc5cfa.json"}}, {"family": "Makaraviciute", "given": "Asta", "initials": "A", "orcid": "0000-0003-3843-7198", "researcher": {"href": "https://publications.scilifelab.se/researcher/9f14031ff310417f9af2b54cc63b905d.json"}}, {"family": "Kumar", "given": "Shalen", "initials": "S"}, {"family": "Wen", "given": "Chenyu", "initials": "C", "orcid": "0000-0003-4395-7905", "researcher": {"href": "https://publications.scilifelab.se/researcher/e2fdf123d31543d2a22fb1eaee3eab0d.json"}}, {"family": "Sj\u00f6din", "given": "Martin", "initials": "M", "orcid": "0000-0003-4126-4347", "researcher": {"href": "https://publications.scilifelab.se/researcher/3abc615673734cadbacd8e6ed1de8829.json"}}, {"family": "Abdurakhmanov", "given": "Eldar", "initials": "E"}, {"family": "Danielson", "given": "U Helena", "initials": "UH", "orcid": "0000-0003-2728-0340", "researcher": {"href": "https://publications.scilifelab.se/researcher/b2bf7dffedf44237807c23718c72efa6.json"}}, {"family": "Nyholm", "given": "Leif", "initials": "L", "orcid": "0000-0001-9292-016X", "researcher": {"href": "https://publications.scilifelab.se/researcher/b7be3793cb034f04a7303a3ba8d0d4bf.json"}}, {"family": "Zhang", "given": "Zhen", "initials": "Z", "orcid": "0000-0003-4317-9701", "researcher": {"href": "https://publications.scilifelab.se/researcher/b84c807f13484a2abf4ab92ab77e37ec.json"}}], "type": "journal article", "published": "2019-11-19", "journal": {"title": "Anal. Chem.", "issn": "1520-6882", "volume": "91", "issue": "22", "pages": "14697-14704", "issn-l": "0003-2700"}, "abstract": "Despite a large number of publications describing biosensors based on electrochemical impedance spectroscopy (EIS), little attention has been paid to the stability and reproducibility issues of the sensor interfaces. In this work, the stability and reproducibility of faradaic EIS analyses on the aptamer/mercaptohexanol (MCH) self-assembled monolayer (SAM)-functionalized gold surfaces in ferri- and ferrocyanide solution were systematically evaluated prior to and after the aptamer-probe DNA hybridization. It is shown that the EIS data exhibited significant drift, and this significantly affected the reproducibility of the EIS signal of the hybridization. As a result, no significant difference between the charge transfer resistance ( RCT) changes induced by the aptamer-target DNA hybridization and that caused by the drift could be identified. A conditioning of the electrode in the measurement solution for more than 12 h was required to reach a stable RCT baseline prior to the aptamer-probe DNA hybridization. The monitored drift in RCT and double layer capacitance during the conditioning suggests that the MCH SAM on the gold surface reorganized to a thinner but more closely packed layer. We also observed that the hot binding buffer used in the following aptamer-probe DNA hybridization process could induce additional MCH and aptamer reorganization, and thus further drift in RCT. As a result, the RCT change caused by the aptamer-probe DNA hybridization was less than that caused by the hot binding buffer (blank control experiment). Therefore, it is suggested that the use of high temperature in the EIS measurement should be carefully evaluated or avoided. This work provides practical guidelines for the EIS measurements. Moreover, because SAM-functionalized gold electrodes are widely used in biosensors, for example, DNA sensors, an improved understanding of the origin of the observed drift is very important for the development of well-functioning and reproducible biosensors.", "doi": "10.1021/acs.analchem.9b03946", "pmid": "31650834", "labels": {"Drug Discovery and Development": "Technology development"}, "xrefs": [], "notes": [], "created": "2020-01-07T14:01:17.339Z", "modified": "2025-10-17T13:05:08.088Z"}]}