RESUMEN
Photoelectrochemical (PEC) sensing is an emerging technological innovation for monitoring small substances/molecules in biological or non-biological systems. In particular, there has been a surge of interest in developing PEC devices for determining molecules of clinical significance. This is especially the case for molecules that are markers for serious and deadly medical conditions. The increased interest in PEC sensors to monitor such biomarkers can be attributed to the many apparent advantages of the PEC system, including an enhanced measurable signal, high potential for miniaturization, rapid testing, and low cost, amongst others. The growing number of published research reports on the subject calls for a comprehensive review of the various findings. This article is a review of studies on electrochemical (EC) and PEC sensors for ovarian cancer biomarkers in the last seven years (2016-2022). EC sensors were included because PEC is an improved EC; and a comparison of both systems has, expectedly, been carried out in many studies. Specific attention was given to the different markers of ovarian cancer and the EC/PEC sensing platforms developed for their detection/quantification. Relevant articles were sourced from the following databases: Scopus, PubMed Central, Web of Science, Science Direct, Academic Search Complete, EBSCO, CORE, Directory of open Access Journals (DOAJ), Public Library of Science (PLOS), BioMed Central (BMC), Semantic Scholar, Research Gate, SciELO, Wiley Online Library, Elsevier and SpringerLink.
Asunto(s)
Técnicas Biosensibles , Neoplasias Ováricas , Humanos , Femenino , Biomarcadores de Tumor , Inmunoensayo , Neoplasias Ováricas/diagnóstico , Técnicas Electroquímicas , Límite de DetecciónRESUMEN
The reaction of 5,5'-dithiobis(2-nitrobenzoate), DTNB, with hemoglobin sulfhydryl groups is linked to three negatively contributing Bohr effect groups: His2ß is present in all avian hemoglobins but absent in some mammalian hemoglobins; His77ß and His143ß are absent in avian but present in nearly all mammalian hemoglobins. To probe the consequences of these differences, we determined the influence of inositol hexakisphosphate (inositol-P6) on the DTNB affinities of avian and mammalian carbonmonoxyhemoglobins. Inositol-P6decreases by two orders of magnitude the DTNB affinity of guinea pig hemoglobin, which has His2ß and the R2 quaternary structure. It decreases, or has no effect on, the DTNB affinities of hemoglobins that have His2ß and whose structures lie along the R2 â R quaternary equilibrium. Finally, inositol-P6increases by one to two orders of magnitude the DTNB affinities of hemoglobins that lack His2ß. Thus His2ß, DTNB and inositol-P6, in combination, distinguish the R2 from the R quaternary structure.
Asunto(s)
Carboxihemoglobina/antagonistas & inhibidores , Ácido Ditionitrobenzoico/química , Ácido Fítico/farmacología , Animales , Carboxihemoglobina/química , Pollos , Cobayas , Concentración de Iones de Hidrógeno , Ácido Fítico/química , Estructura Cuaternaria de ProteínaRESUMEN
We have measured the affinity of the CysF9[93]ß sulfhydryl group of human deoxyhemoglobin and oxyhemoglobin for 5,5'-dithiobis(2-nitrobenzoate), DTNB, between pH ≈5.6 and 9 in order to understand the basis of the reported reduction of the Bohr effect induced by chemical modification of the sulfhydryl. We analyzed the results quantitatively on the basis of published data indicating that the sulfhydryl exists in two conformations that are coupled to the transition between two tertiary structures of hemoglobin in dynamic equilibrium. Our analyses show that the ionizable groups linked to the DTNB reaction have lower pKas of ionization in deoxyhemoglobin compared to oxyhemoglobin. So these ionizable groups should make negative contributions to the Bohr effect. We identify these groups as HisNA2[2]ß, HisEF1[77]ß and HisH21[143]ß. We provide explanations for the finding that hemoglobin, chemically modified at CysF9[93]ß, has a lower Bohr effect and a higher oxygen affinity than unmodified hemoglobin.