Breaking barriers in electrochemical biosensing using bioinspired peptide and phage probes.

Electrochemical biosensing continues to advance tirelessly, overcoming barriers that have kept it from leaving research laboratories for many years. Among them, its compromised performance in complex biological matrices due to fouling or receptor stability issues, the limitations in determining toxic and small analytes, and its use, conditioned to the commercial availability of commercial receptors and the exploration of natural molecular interactions, deserved to be highlighted. To address these challenges, in addition to the intrinsic properties of electrochemical biosensing, its coupling with biomimetic materials has played a fundamental role, among which bioinspired phage and peptide probes stand out. The versatility in design and employment of these probes has opened an unimaginable plethora of possibilities for electrochemical biosensing, improving their performance far beyond the development of highly sensitive and selective devices. The state of the art offers robust electroanalytical biotools, capable of operating in complex samples and with exciting opportunities to discover and determine targets regardless of their toxicity and size, the commercial availability of bioreceptors, and prior knowledge of molecular interactions. With all this in mind, this review offers a panoramic, novel, and updated vision of both the tremendous advances and opportunities offered by the combination of electrochemical biosensors with bioinspired phage and peptide probes and the challenges and research efforts that are envisioned in the immediate future.

First bioelectronic immunoplatform for quantitative secretomic analysis of total and metastasis-driven glycosylated haptoglobin.

The glycosylation status of proteins is increasingly used as biomarker to improve the reliability in the diagnosis and prognosis of diseases as relevant as cancer. This feeds the need for tools that allow its simple and reliable analysis and are compatible with applicability in the clinic. With this objective in mind, this work reports the first bioelectronic immunoplatforms described to date for the determination of glycosylated haptoglobin (Hp) and the simultaneous determination of total and glycosylated Hp. The bioelectronic immunoplatform is based on the implementation of non-competitive bioassays using two different antibodies or an antibody and a lectin on the surface of commercial magnetic microcarriers. The resulting bioconjugates are labeled with the horseradish peroxidase (HRP) enzyme, and after their magnetic capture on disposable electroplatforms, the amperometric transduction using the H2O2/hydroquinone (HQ) system allows the single or multiple detection. The developed immunoplatform achieves limits of detection (LODs) of 0.07 and 0.46 ng mL-1 for total and glycosylated Hp in buffer solution, respectively. The immunoplatform allows accurate determination using simple and relatively short protocols (approx. 75 min) of total and glycosylated Hp in the secretomes of in vitro-cultured colorectal cancer (CRC) cells with different metastatic potentials, which is not feasible, due to lack of sensitivity, by means of some commercial ELISA kits and Western blot methodology.

Short- and long-term prognostic factors associated with functional recovery in elderly patients with hip fracture: A systematic review.

This systematic review aimed to identify short- and long-term associated factors to functional recovery of elderly hip fracture patients after discharge. We identified 43 studies reporting 74 associated factors to functional recovery; most of them were biological, sociodemographic, or inherent factors to patients' baseline characteristics, including their pre-facture functional capacity. PURPOSE: This systematic review aimed to identify short- and long-term associated factors to functional recovery of elderly hip fracture patients after hospital discharge. We assessed the use of the hip fracture core-set and key-performance indicators for secondary fracture reduction. METHODS: A search was performed in seven electronic databases. Observational studies reporting predictors after usual care of elderly patients with hip fracture diagnoses receiving surgical or conservative treatment were included. Primary outcomes considered were part of the domains corresponding to functional capacity. RESULTS: Of 3873 references identified, and after the screening and selection process, 43 studies were included. Sixty-one functional measures were identified for ten functional outcomes, including BADLs, IADLs, ambulation, and mobility. Biological characteristics such as age, sex, comorbidities, cognitive status, nutritional state, and biochemical parameters are significantly associated. Determinants such as contact and size of social network and those related to institutional care quality are relevant for functional recovery at six and 12 months. Age, pre-fracture function, cognitive status, and complications continue to be associated five years after discharge. We found 74 associated factors to functional recovery of elderly hip fracture patients. Ten of the studies reported rehabilitation programs as suggested in KPI 9; none used the complete hip fracture core-set. CONCLUSION: Most of the associated factors for functional recovery of elderly hip fracture were biological, sociodemographic, or inherent factors to patients' baseline characteristics, including their pre-facture functional capacity. For the core-set and KPI's, we found an insufficient use and report. This study reports 61 different instruments to measure functional capacity. REGISTRATION NUMBER: PROSPERO (CRD42020149563).

Anticipating metastasis through electrochemical immunosensing of tumor hypoxia biomarkers.

Metastasis is responsible for about 90% of cancer-associated deaths. In the context of solid tumors, the low oxygen concentration in the tumor microenvironment (hypoxia) is one of the key factors contributing to metastasis. Tumor cells adapt to these conditions by overexpressing certain proteins such as programmed death ligand 1 (PD-L1) and hypoxia-inducible factor 1 alpha (HIF-1α). However, the determination of these tumor hypoxia markers that can be used to follow-up tumor progression and improve the efficiency of therapies has been scarcely addressed using electrochemical biosensors. In this work, we report the first electrochemical bioplatform for the determination of PD-L1 as well as the first one allowing its simultaneous determination with HIF-1α. The target proteins were captured and enzymatically labeled on magnetic microbeads and amperometric detection was undertaken on the surface of screen-printed dual carbon electrodes using the hydrogen peroxide/peroxidase/hydroquinone system. Sandwich immunoassays were implemented for both the HIF-1α and PD-L1 sensors and the analytical characteristics were evaluated providing LOD values of 86 and 279 pg mL-1 for the amperometric determination of PD-L1 and HIF-1α standards, respectively. The developed electrochemical immunoplatforms are competitive versus the only electrochemical immunosensor reported for the determination of HIF-1α and the "gold standard" ELISA methodology for the single determination of both proteins in terms of assay time, compatibility with the simultaneous determination of both proteins making their use suitable for untrained users at the point of attention. The dual amperometric immunosensor was applied to the simultaneous determination of HIF-1α and PD-L1 in cancer cell lysates. The analyses lasted only 2 h and just 0.5 µg of the sample was required.

Evidence based Latin American Guidelines of clinical practice on prevention, diagnosis, management and treatment of glucocorticoid induced osteoporosis. A 2022 update : This manuscript has been produced under the auspices of the Committee of National Societies (CNS) and the Committee of Scientific Advisors (CSA) of the International Osteoporosis Foundation (IOF).

Guidelines and recommendations developed and endorsed by the International Osteoporosis Foundation (IOF) are intended to provide guidance for particular pattern of practice for physicians who usually prescribe glucocorticoid (GC) therapy, and not to dictate the care of a particular patient. Adherence to the recommendations within this guideline is voluntary and the ultimate determination regarding their application should be made by the physician in light of each patient's circumstances. Guidelines and recommendations are intended to promote a desirable outcome but cannot guarantee any specific outcome. This guideline and its recommendations are not intended to dictate payment, reimbursement or insurance decisions. Guidelines and recommendations are subjected to periodic revisions as a consequence of the evolution of medicine, technology and clinical practice. A panel of Latin American (LATAM) experts specialized in osteoporosis with recognized clinical experience in managing patients with glucocorticoid-induced osteoporosis (GIO) met to produce evidence-based LATAM recommendations for the diagnosis and management of GIO. These guidelines are particularly intended to general practitioners and primary care physicians who prescribe GC treatments in LATAM to guide their daily clinical practice in terms of evaluation, prevention and treatment of GIO. These recommendations were based on systematic literature review using MEDLINE, EMBASE, SCOPUS and COCHRANE Library database during the period from 2012 to 2021. Randomized clinical trials (RCT), systematic reviews of RCT, controlled observational studies, guidelines and consensus were considered. Based on the review and expert opinion the panel members voted recommendations during two successive rounds of voting by panel members. Agreements for each statement were considered if a concordance of at least 70% was achieved following Delphi methodology. Grading of recommendations was made according to the Oxford Centre for the Evidence-based Medicine (EBM) criteria. Among five GIO guidelines and consensus initially identified, two of them (American College of Rheumatology 2017 and the Brazilian Guidelines 2021) were selected for comparison considering the latter as the most current guides in the LATAM region. Based on this methodology fifty statements were issued. All of them but four (1.20, 1.21, 1.23 and 4.2) attained agreement.

What is the quality of life of adults with vitiligo in Mexico?

INTRODUCTION: Vitiligo is an incurable, slowly progressive skin condition, the prevalence of which ranges from 0.4 to 2.0%. Health-related quality of life (HRQoL) refers to self-perceived well-being associated with the presence of a disease and its treatment. METHODS: Cross-sectional study at a dermatological center. Adults with non-segmental vitiligo (NSV) were included, while patients with other pigmentary disorders and other types of vitiligo were excluded. The VitiQoL questionnaire (0 = no skin involvement, 90 = maximum skin involvement), the Vitiligo Extent Score (VES) and the Vitiligo Area Scoring Index (VASI) were applied. RESULTS: 492 patients did participate; 63% were women. An average score of 32.6 was obtained on VitiQoL (95% CI = 30.6-34.5). Self-perception of severity and HRQoL were correlated (r = 0.568, p < 0.001). Age, the female gender, lower education and higher self-perceived severity were associated with poorer HRQoL. The proportion of subjects who reported an addiction was similar in the worst and best HRQoL groups (28% vs. 32%, p = 0.23). CONCLUSION: Poorer HRQoL is explained by severity self-perception, concern about disease progression, appearance of the skin and necessary actions to avoid sun exposure during recreation.

INTRODUCCIÓN: El vitiligo es incurable, lentamente progresivo, su prevalencia varía de 0.4 a 2.0 %. La calidad de vida relacionada con la salud (CVRS) se refiere al bienestar autopercibido asociado a la presencia de una enfermedad y su tratamiento. MÉTODOS: Estudio transversal en un centro dermatológico. Se incluyeron adultos con vitiligo no segmentario (VNS), en tanto que se excluyeron pacientes con otros trastornos pigmentarios y otros tipos de vitiligo. Se aplicó el cuestionario VitiQoL (0 = sin afectación, 90 = máxima afectación), el Vitiligo Extent Score (VES) y el Vitiligo Area Scoring Index (VASI). RESULTADOS: Participaron 492 pacientes, 63 % mujeres. Se obtuvieron 32.6 puntos de promedio en el VitiQoL (IC 95 % = 30.6-34.5). La autopercepción de gravedad y la CVRS se correlacionaron (r = 0.568, p < 0.001). La edad, el sexo femenino, la menor educación y la mayor gravedad autopercibida se asociaron a peor CVRS. La proporción de personas que reportaron una adicción fue similar en los grupos con peor y mejor CVRS (28 % versus 32 %, p = 0.23). CONCLUSIÓN: La peor CVRS se explica por la autopercepción de gravedad, preocupación por la progresión de la enfermedad, aspecto de la piel y acciones necesarias para evitar la exposición al sol durante la recreación.

Disposable immunoplatforms for the simultaneous determination of biomarkers for neurodegenerative disorders using poly(amidoamine) dendrimer/gold nanoparticle nanocomposite.

Early diagnosis in primary care settings can increase access to therapies and their efficiency as well as reduce health care costs. In this context, we report in this paper the development of a disposable immunoplatform for the rapid and simultaneous determination of two protein biomarkers recently reported to be involved in the pathological process of neurodegenerative disorders (NDD), tau protein (tau), and TAR DNA-binding protein 43 (TDP-43). The methodology involves implementation of a sandwich-type immunoassay on the surface of dual screen-printed carbon electrodes (dSPCEs) electrochemically grafted with p-aminobenzoic acid (p-ABA), which allows the covalent immobilization of a gold nanoparticle-poly(amidoamine) (PAMAM) dendrimer nanocomposite (3D-Au-PAMAM). This scaffold was employed for the immobilization of the capture antibodies (CAbs). Detector antibodies labeled with horseradish peroxidase (HRP) and amperometric detection at - 0.20 V (vs. Ag pseudo-reference electrode) using the H2O2/hydroquinone (HQ) system were used. The developed methodology exhibits high sensitivity and selectivity for determining the target proteins, with detection limits of 2.3 and 12.8 pg mL-1 for tau and TDP-43, respectively. The simultaneous determination of tau and TDP-43 was accomplished in raw plasma samples and brain tissue extracts from healthy individuals and NDD-diagnosed patients. The analysis can be performed in just 1 h using a simple one-step assay protocol and small sample amounts (5 µL plasma and 2.5 µg brain tissue extracts). Graphical abstract.

Development and Validation of a New Scoring Tool to Evaluate the Clinical Evolution of Adult Patients with Nonsegmental Vitiligo.

BACKGROUND: Vitiligo has an unpredictable course and a variable response to treatment. Furthermore, the improvement of some vitiligo lesions cannot be considered a guarantee of a similar response to the other lesions. Instruments for patient-reported outcome measures (PROM) can be an alternative to measure complex constructions such as clinical evolution. OBJECTIVE: The aim of this study was to validate a PROM that allows to measure the clinical evolution of patients with nonsegmental vitiligo in a simple but standardized way that serves to gather information for a better understanding of the disease. METHODS: The instrument was created through expert consensus and patient participation. For the validation study, a prospective cohort design was performed. The body surface area affected was measured with the Vitiligo Extension Score (VES), the extension, the stage, and the spread by the evaluation of the Vitiligo European Task Force assessment (VETFa). Reliability was determined with test-retest, construct validity through hypothesis testing, discriminative capacity with extreme groups, and response capacity by comparing initial and final measurements. RESULTS: Eighteen semi-structured interviews and 7 cognitive interviews were conducted, and 4 dermatologists were consulted. The instrument Clinical Evolution-Vitiligo (CV-6) was answered by 119 patients with a minimum of primary schooling. A wide range was observed in the affected body surface; incident and prevalent cases were included. The average time to answer the CV-6 was 3.08 ± 0.58 min. In the test-retest (n = 53), an intraclass correlation coefficient was obtained: 0.896 (95% CI 0.82-0.94; p < 0.001). In extreme groups, the mean score was 2 (2-3) and 5 (4-6); p < 0.001. The initial CV-6 score was different from the final one and the change was verified with VES and VETFa (p < 0.05, n = 92). CONCLUSIONS: The CV-6 instrument allows patient collaboration, it is simple and brief, and it makes it easier for the doctor to focus attention on injuries that present changes at the time of medical consultation.

Amperometric Bioplatforms To Detect Regional DNA Methylation with Single-Base Sensitivity.

This work reports the first bioplatform able to determine electrochemically 5-hydroxymethylcytosine (5-hmC) methylation events at localized sites and single-base sensitivity. The described bioplatform relies on a specific antibody (anti-5-hmC), further conjugated with commercial bioreagents loaded with multiple horseradish peroxidase (HRP) molecules, recognizing the epimark in a target DNA, captured through hybridization onto streptavidin-magnetic microbeads (Strep-MBs) modified with a complementary DNA capture probe. The electrochemical detection is performed by amperometry (-0.20 V vs Ag pseudoreference electrode) at disposable screen-printed carbon electrodes (SPCEs) in the presence of H2O2/hydroquinone (HQ) upon magnetic capture of the modified MBs onto the SPCE. The use of the commercial bioreagents ProtA-polyHRP80 and Histostar, very scarcely explored so far in electrochemical biosensors, provides high sensitivities for a synthetic target DNA sequence with a unique 5-hmC in the promoter region of MGMT tumor suppressor gene. Amplification factors of 43.6 and 55.2 were achieved using ProtA-polyHRP80 or Histostar, respectively, compared to the conventional secondary antibody labeling. This amplification was crucial to detect methylation events at single-nucleotide resolution achieving limits of detection (LODs) of 23.0 and 13.2 pM, respectively, without any target DNA amplification. The ProtA-polyHRP80-based bioplatform, selected as a compromise between sensitivity and cost per determination, exhibited full discrimination toward the target 5-hmC against the closely related 5-mC. In addition, the bioplatform detected 5-hmC at the regional level (MGMT promoter region) in just 10 ng of genomic DNA (gDNA, ∼2700 genomes) extracted from cancer cells and tissues from colorectal cancer (CRC) patients within 60 min.

A novel peptide-based electrochemical biosensor for the determination of a metastasis-linked protease in pancreatic cancer cells.

Proteases are involved in cancer' taking part in immune (dis)regulation, malignant progression and tumour growth. Recently, it has been found that expression levels of one of the members of the serine protease family, trypsin, is upregulated in human cancer cells of several organs, being considered as a specific cancer biomarker. Considering the great attention that electrochemical peptide sensors have nowadays, in this work, we propose a novel electroanalytical strategy for the determination of this important biomolecule. It implies the immobilization of a short synthetic peptide sequence, dually labelled with fluorescein isothiocyanate (FITC) and biotin, onto neutravidin-modified magnetic beads (MBs), followed by the peptide digestion with trypsin. Upon peptide disruption, the modified MBs were incubated with a specific fluorescein Fab fragment antibody labelled with horseradish peroxidase (HRP-antiFITC) and magnetically captured on the surface of a screen-printed carbon electrode (SPCE), where amperometric detection was performed using the hydroquinone (HQ)/HRP/H2O2 system. The biosensor exhibited a good reproducibility of the measurements (RSD 3.4%, n = 10), and specificity against other proteins and proteases commonly found in biological samples. This work reports the first quantitative data so far on trypsin expression in human cell lysates. The developed bioplatform was used for the direct determination of this protease in lysates from pancreatic cancer, cervix carcinoma and kidney cells in only 3 h and 30 min using low amounts (~ 0.1 µg) of raw extracts. Graphical abstract.

A novel zinc finger protein-based amperometric biosensor for miRNA determination.

This paper reports a simple electrochemical strategy for the determination of microRNAs (miRNAs) using a commercial His-Tag-Zinc finger protein (His-Tag-ZFP) that binds preferably (but non-sequence specifically) RNA hybrids over ssRNAs, ssDNAs, and dsDNAs. The strategy involves the use of magnetic beads (His-Tag-Isolation-MBs) as solid support to capture the conjugate formed in homogenous solution between His-Tag-ZFP and the dsRNA homohybrid formed between the target miRNA (miR-21 selected as a model) and a biotinylated synthetic complementary RNA detector probe (b-RNA-Dp) further conjugated with a streptavidin-horseradish peroxidase (Strep-HRP) conjugate. The electrochemical detection is carried out by amperometry at disposable screen-printed carbon electrodes (SPCEs) (- 0.20 V vs Ag pseudo-reference electrode) upon magnetic capture of the resultant magnetic bioconjugates and H2O2 addition in the presence of hydroquinone (HQ). The as-prepared biosensor exhibits a dynamic concentration range from 3.0 to 100 nM and a detection limit (LOD) of 0.91 nM for miR-21 in just ~ 2 h. An acceptable discrimination was achieved between the target miRNA and other non-target nucleic acids (ssDNA, dsDNA, ssRNA, DNA-RNA, miR-122, miR-205, and single central- or terminal-base mismatched sequences). The biosensor was applied to the analysis of miR-21 from total RNA (RNAt) extracted from epithelial non-tumorigenic and adenocarcinoma breast cells without target amplification, pre-concentration, or reverse transcription steps. The versatility of the methodology due to the ZFP's non-sequence-specific binding behavior makes it easily extendable to determine any target RNA only by modifying the biotinylated detector probe.

Nanozymes in electrochemical affinity biosensing.

Over the past decade, artificial nanomaterials that exhibit properties similar to those of enzymes are gaining attraction in electrochemical biosensing as highly stable and low-cost alternatives to enzymes. This review article discusses the main features of the various nanomaterials (metal oxide, metal, and carbon-based materials) explored so far to mimic different kinds of enzymes. The unprecedented opportunities imparted by these functional nanomaterials or their nanohybrids, mostly providing peroxidase-like activity, in electrochemical affinity biosensing are critically discussed mainly in connection with their use as catalytic labels or electrode surface modifiers by highlighting representative strategies reported in the past 5 years with application in the food, environmental, and biomedical fields. Apart from outlining the pros and cons of nanomaterial-based enzyme mimetics arising from the impressive development they have experienced over the last few years, current challenges and future directions for achieving their widespread use and exploiting their full potential in the development of electrochemical biosensors are discussed. Graphical abstract.

Beyond Sensitive and Selective Electrochemical Biosensors: Towards Continuous, Real-Time, Antibiofouling and Calibration-Free Devices.

Nowadays, electrochemical biosensors are reliable analytical tools to determine a broad range of molecular analytes because of their simplicity, affordable cost, and compatibility with multiplexed and point-of-care strategies. There is an increasing demand to improve their sensitivity and selectivity, but also to provide electrochemical biosensors with important attributes such as near real-time and continuous monitoring in complex or denaturing media, or in vivo with minimal intervention to make them even more attractive and suitable for getting into the real world. Modification of biosensors surfaces with antibiofouling reagents, smart coupling with nanomaterials, and the advances experienced by folded-based biosensors have endowed bioelectroanalytical platforms with one or more of such attributes. With this background in mind, this review aims to give an updated and general overview of these technologies as well as to discuss the remarkable achievements arising from the development of electrochemical biosensors free of reagents, washing, or calibration steps, and/or with antifouling properties and the ability to perform continuous, real-time, and even in vivo operation in nearly autonomous way. The challenges to be faced and the next features that these devices may offer to continue impacting in fields closely related with essential aspects of people's safety and health are also commented upon.

Systematic Review of Clinimetric Instruments to determine the severity of Non-segmental Vitiligo.

This systematic review of measurement instruments for vitiligo outcomes included validation articles published from 2011 to May 2018. According to the PRISMA statement, the search was carried out in EMBASE (via OvidSP); MEDLINE (via OvidSP and PubMed). The COSMIN taxonomy will be used to define the measurement properties. Inclusion criteria were original studies reporting measuring properties. Exclusion criteria were clinical trials using scales whose measurement properties were not assessed, studies of cross-cultural adaptation, scales focused on other aspects of the disease such as quality of life, satisfaction, disease's burden. Fourteen studies were identified, which described 15 instruments to measure vitiligo outcomes. Nine of them, measured properties related to the severity of the disease: Vitiligo extent score (VES), Self-Assessment Vitiligo Extent Score (SA-VES), Self-Assessed Vitiligo Area Scoring Index (SAVASI), Vitiligo Area Scoring Index (VASI), Vitiligo European Task Force assessment (VETFa), Vitíligo Noticeability Scale (VNS), Koebner's phenomenon in vitiligo score (K-VSCOR), Vitiligo Extent Tensity Index (VETI), Potential Repigmentation Index (PRI). The most effective tool to asses affected Body Surface Area (BSA) is VES. The VASI is useful to stratify by severity. There is not enough evidence to recommend the use of SAVASI. The VETFa does not offer any difference to calculate the affected BSA compared with the rule of 9's. The VNS and K-VSCOR lack of reliability evidence.

Opportunities, Challenges, and Prospects in Electrochemical Biosensing of Circulating Tumor DNA and its Specific Features.

Nowadays, analyzing circulating tumor DNA (ctDNA), a very small part of circulating free DNA (cfDNA) carried by blood, is considered to be an interesting alternative to conventional single-site tumor tissue biopsies, both to assess tumor burden and provide a more comprehensive snapshot of the time-related and spatial heterogeneity of cancer genetic/epigenetic scenery. The determination of ctDNA and/or mapping its characteristic features, including tumor-specific mutations, chromosomal aberrations, microsatellite alterations, and epigenetic changes, are minimally invasive, powerful and credible biomarkers for early diagnosis, follow-up, prediction of therapy response/resistance, relapse monitoring, and tracking the rise of new mutant subclones, leading to improved cancer outcomes This review provides an outline of advances published in the last five years in electrochemical biosensing of ctDNA and surrogate markers. It emphasizes those strategies that have been successfully applied to real clinical samples. It highlights the unique opportunities they offer to shift the focus of cancer patient management methods from actual decision making, based on clinic-pathological features, to biomarker-driven treatment strategies, based on genotypes and customized targeted therapies. Also highlighted are the unmet hurdles and future key points to guide these devices in the development of liquid biopsy cornerstone tools in routine clinical practice for the diagnosis, prognosis, and therapy response monitoring in cancer patients.

Antifouling (Bio)materials for Electrochemical (Bio)sensing.

(Bio)fouling processes arising from nonspecific adsorption of biological materials (mainly proteins but also cells and oligonucleotides), reaction products of neurotransmitters oxidation, and precipitation/polymerization of phenolic compounds, have detrimental effects on reliable electrochemical (bio)sensing of relevant analytes and markers either directly or after prolonged incubation in rich-proteins samples or at extreme pH values. Therefore, the design of antifouling (bio)sensing interfaces capable to minimize these undesired processes is a substantial outstanding challenge in electrochemical biosensing. For this purpose, efficient antifouling strategies involving the use of carbon materials, metallic nanoparticles, catalytic redox couples, nanoporous electrodes, electrochemical activation, and (bio)materials have been proposed so far. In this article, biomaterial-based strategies involving polymers, hydrogels, peptides, and thiolated self-assembled monolayers are reviewed and critically discussed. The reported strategies have been shown to be successful to overcome (bio)fouling in a diverse range of relevant practical applications. We highlight recent examples for the reliable sensing of particularly fouling analytes and direct/continuous operation in complex biofluids or harsh environments. Opportunities, unmet challenges, and future prospects in this field are also pointed out.

Rapid Electrochemical Assessment of Tumor Suppressor Gene Methylations in Raw Human Serum and Tumor Cells and Tissues Using Immunomagnetic Beads and Selective DNA Hybridization.

We report a rapid and sensitive electrochemical strategy for the detection of gene-specific 5-methylcytosine DNA methylation. Magnetic beads (MBs) modified with an antibody for 5-methylcytosines (5-mC) are used for the capture of any 5-mC methylated single-stranded (ss)DNA sequence. A flanking region next to the 5-mCs of the captured methylated ssDNA is recognized by hybridization with a synthetic biotinylated DNA sequence. Amperometric transduction at disposable screen-printed carbon electrodes (SPCEs) is employed. The developed biosensor has a dynamic range from 3.9 to 500 pm and a limit of detection of 1.2 pm for the methylated synthetic sequence of the tumor suppressor gene O-6-methylguanine-DNA methyltransferase (MGMT) promoter region. The method is applied in the 45-min analysis of specific methylation in the MGMT promoter region directly in raw spiked human serum samples and in genomic DNA extracted from U-87 glioblastoma cells and paraffin-embedded brain tumor tissues without any amplification and pretreatment step.

Non-Invasive Breast Cancer Diagnosis through Electrochemical Biosensing at Different Molecular Levels.

The rapid and accurate determination of specific circulating biomarkers at different molecular levels with non- or minimally invasive methods constitutes a major challenge to improve the breast cancer outcomes and life quality of patients. In this field, electrochemical biosensors have demonstrated to be promising alternatives against more complex conventional strategies to perform fast, accurate and on-site determination of circulating biomarkers at low concentrations in minimally treated body fluids. In this article, after discussing briefly the relevance and current challenges associated with the determination of breast cancer circulating biomarkers, an updated overview of the electrochemical affinity biosensing strategies emerged in the last 5 years for this purpose is provided highlighting the great potentiality of these methodologies. After critically discussing the most interesting features of the electrochemical strategies reported so far for the single or multiplexed determination of such biomarkers with demonstrated applicability in liquid biopsy analysis, existing challenges still to be addressed and future directions in this field will be pointed out.

Magnetic Beads-Based Sensor with Tailored Sensitivity for Rapid and Single-Step Amperometric Determination of miRNAs.

This work describes a sensitive amperometric magneto-biosensor for single-step and rapid determination of microRNAs (miRNAs). The developed strategy involves the use of direct hybridization of the target miRNA (miRNA-21) with a specific biotinylated DNA probe immobilized on streptavidin-modified magnetic beads (MBs), and labeling of the resulting heteroduplexes with a specific DNA-RNA antibody and the bacterial protein A (ProtA) conjugated with an horseradish peroxidase (HRP) homopolymer (Poly-HRP40) as an enzymatic label for signal amplification. Amperometric detection is performed upon magnetic capture of the modified MBs onto the working electrode surface of disposable screen-printed carbon electrodes (SPCEs) using the H2O2/hydroquinone (HQ) system. The magnitude of the cathodic signal obtained at -0.20 V (vs. the Ag pseudo-reference electrode) demonstrated linear dependence with the concentration of the synthetic target miRNA over the 1.0 to 100 pM range. The method provided a detection limit (LOD) of 10 attomoles (in a 25 µL sample) without any target miRNA amplification in just 30 min (once the DNA capture probe-MBs were prepared). This approach shows improved sensitivity compared with that of biosensors constructed with the same anti-DNA-RNA Ab as capture instead of a detector antibody and further labeling with a Strep-HRP conjugate instead of the Poly-HRP40 homopolymer. The developed strategy involves a single step working protocol, as well as the possibility to tailor the sensitivity by enlarging the length of the DNA/miRNA heteroduplexes using additional probes and/or performing the labelling with ProtA conjugated with homopolymers prepared with different numbers of HRP molecules. The practical usefulness was demonstrated by determination of the endogenous levels of the mature target miRNA in 250 ng raw total RNA (RNAt) extracted from human mammary epithelial normal (MCF-10A) and cancer (MCF-7) cells and tumor tissues.

[Diagnóstico tardío de psoriasis: motivos y consecuencias]. / Late diagnosis of psoriasis: Reasons and consequences.

BACKGROUND: Psoriasis is an autoimmune skin disease that may be associated with articular manifestations, and the most common clinical presentation is the variety "in plaques". In Mexico, in the Centro Dermatológico Pascua, it is the eighth leading cause of consultation. The aim of this study was to determine the diagnostic process of patients in a reference center for diseases of the skin. METHODS: Performing an analytical cross-sectional study that included 100 patients where the diagnostic process was questioned, clinimetric scales were applied and evaluated anthropometric. RESULTS: It was found that 70% of patients had taken over a month to get medical care (median: 3 months; IQR: 11 months), having consulted in 61% to a general physician as a doctor of first contact and 89% being diagnosed by a dermatologist. Eighty-eight percent of the patients were overweight or obese. We found as a factor of delay, a partnership with the variable of having an Institutional Medical Service (p = 0.019; U = 695.5). CONCLUSION: it is necessary to design a system to shorten the diagnostic process, not only in psoriasis, in addition to emphasizing dermatological education.