Nucleic acid-based biosensors: analytical devices for prevention, diagnosis and treatment of diseases

BACKGROUND : Biosensing techniques have been the subject of exponentially increasing interest due to their performance advantages such as high selectivity and sensitivity, easy operation, low cost, short analysis time, simple sample preparation, and real-time detection. Biosensors have been developed by integrating the unique specificity of biological reactions and the high sensitivity of physical sensors. Therefore, there has been a broad scope of applications for biosensing techniques, and nowadays, they are ubiquitous in different areas of environmental, healthcare, and food safety. Biosensors have been used for environmental studies, detecting and quantifying pollutants in water, air, and soil. Biosensors also showed great potential for developing analytical tools with countless applications in diagnosing, preventing, and treating diseases, mainly by detecting biomarkers. Biosensors as a medical device can identify nucleic acids, proteins, peptides, metabolites, etc.; these analytes may be biomarkers associated with the disease status. Bacterial food contamination is considered a worldwide public health issue; biosensor-based analytical techniques can identify the presence or absence of pathogenic agents in food. OBJECTIVES: The present review aims to establish state-of-the-art, comprising the recent advances in the use of nucleic acid-based biosensors and their novel application for the detection of nucleic acids. Emphasis will be given to the performance characteristics, advantages, and challenges. Additionally, food safety applications of nucleic acid-based biosensors will be discussed. METHODS: Recent research articles related to nucleic acid-based biosensors, biosensors for detecting nucleic acids, biosensors and food safety, and biosensors in environmental monitoring were reviewed. Also, biosensing platforms associated with the clinical diagnosis and food industry were included. RESULTS: It is possible to appreciate that multiple applications of nucleic acid-based biosensors have been reported in the diagnosis, prevention, and treatment of diseases, as well as to identify foodborne pathogenic bacteria. The use of PNA and aptamers opens the possibility of developing new biometric tools with better analytical properties. CONCLUSIONS: Biosensors could be considered the most important tool for preventing, treating, and monitoring diseases that significantly impact human health. The aptamers have advantages as biorecognition elements due to the structural conformation, hybridization capacity, robustness, stability, and lower costs. It is necessary to implement biosensors in situ to identify analytes with high selectivity and lower detection limits.

Optimization of ozone concentration and storage time in green asparagus (Asparagus officinalis L.) using response surface methodology

Background: Asparagus (Asparagus officinalis L.) green is a vegetable with a great demand worldwide, and likewise, it is highly perishable due to its high respiration rate that accelerates its senescence. Disinfection of vegetables after their harvest is an obligatory practice that can reduce losses by decomposition due to the attack of microorganisms. Therefore, it is vital to preserving its microbiological and sensory characteristics to reach the final consumer. Objective: To evaluate the effect of gaseous ozone (0 to 10 ppm) and storage time (0 to 30 days) on phenol content, overall appearance, count of molds, psychrophilic bacteria, and viable mesophilic aerobes. Methods: the response surface methodology was used, applying a rotatable central composite design. Results: The results indicated that there was a significant influence (p <0.05) of the independent variables on the characteristics studied, as well as an adequate lack of fit of the quadratic regression model (p> 0.05). By means of the contour superposition technique, it was determined that the optimal conditions for the highest retention of phenol content (16.99 mg/g) and overall appearance (7.61 points) and lower counts of viable aerobic mesophilic bacteria (5.3 x 103 CFU/g) they corresponded to 10 ppm of gaseous ozone up to 25.91 days of storage, with adequate quality characteristics in the shoots. Conclusion: the region of interest was determined for optimal retention of phenol content and overall appearance, and a lower count of viable aerobic mesophilic bacteria in green asparagus during postharvest, suggesting to use the initial application of ozone gas at 10 ppm allowing 25.9 days storage at 1 °C. The results indicate that this technology is a good alternative in the conservation of fresh vegetables.

Comparison of the Effectiveness of Leaf Extracts of Anredera cordifolia, Psidium guajava and Pogostemon cablin on Inhibitory Power Over Escherichia coli Bacteria

Background: the current research studies why it is effective using Anredera cordifolia, Psidium guajava, and Pogostemon cablin by the local community as a traditional medicine for diarrhea treatment caused by Escherichia colibacteria. Objectives: We compared the inhibitor effectiveness of three leaf extracts against Escherichia coli; we also identified the anti-bacterial substances contained in leaf extracts. Methods: We determined the bacterial test activity using the "agar diffusion" method and the thin layer chromatography (TLC) as qualitative analysis for determining the anti-bacterial substances contained in the extract. Results: The Pogostemon cablin leaf extract contained terpenoids, phenolic, and flavonoids compound as bacterial inhibitors, and the comparison showed that Pogostemon cablin leaf extract had the greatest bacterial inhibition power. Conclusion: The antibiotic substances found in the leaf extracts of Anredera cordifolia, Psidium guajava, and Pogostemon cablin can be used as traditional medicine. The breakthrough was evidenced by the ability to inhibit Escherichia coli bacteria. This research shows that traditional medicine has ancient knowledge used by this paper

Gliptins vs. Milk-derived Dipeptidyl-Peptidase IV Inhibiting Biopeptides: Physicochemical Characterization and Pharmacokinetic Profiling

Background: Milk-derived biopeptides have reported in vitro dipeptidyl-peptidase IV (DPP-IV) inhibition, suggesting a glycemic-regulatory effect in Type 2 Diabetes Mellitus (T2DM). Nonetheless, the therapeutic application of these nutraceuticals is limited by the scarcity of knowledge regarding their pharmacokinetic profile. Objective: This study aimed to characterize and assess the pharmacokinetics of milk-derived biopeptides. Through an in silico comparative analysis with gliptins, we expected to identify enhanced properties in food-hydrolysates and suitable DPP-IV inhibiting peptides as candidates for T2DM therapy. Methods: A comparison between gliptins and biopeptides was conducted based on in silico evaluation of drug-likeness, physicochemical properties, pharmacokinetics, and synthetic accessibility. Suitable target proteins for gastrointestinal-absorbable biopeptides were determined as well. Data collection was performed on SwissADME, ADMETlab, DrugBank, SwissTargetPrediction, ChemDes, and BIOPEP-UWM platforms. Statistical analysis was carried out using a one-way ANOVA test. Results: Drug-likeness compliance showed no significant difference between gliptins and biopeptides (p>0.05) in three out of nine assessed rules, though gastrointestinal-absorbable biopeptides exhibited no significant difference with gliptins in five drug-likeness guidelines. The physicochemical evaluation revealed a significant difference (p<0.05) between both groups, with peptides exhibiting enhanced solubility, flexibility, and polarity. Nine out of thirty-six assessed biopeptides reported being likely gastrointestinal-absorbable molecules, from which six displayed ≥30% predicted bioavailability, two reported CYP450 interactions, and all were determined to be blood confined. Biopeptides showed a slightly lower clearance than gliptins yet counteracted by a significantly lower half-life. Moreover, synthetic accessibility scores indicated higher synthetic ease for biopeptides. In addition, absorbable bioactive peptides reported a considerable binding affinity to DPP-IV and Calpain-I. Conclusions: Compared to gliptins, gastrointestinal-absorbable biopeptides exhibit superior physicochemical properties (higher solubility, flexibility, and polarity), lesser CYP450 interactions, higher synthetic ease, and some reported an important affinity for DPP-IV and Calpain-I. Only a small fraction of milk-derived biopeptides are suitable drug-like compounds and feasible candidates for T2DM therapy; yet, testing their therapeutic potency remains subject to further studies.

Wound healing activity of Allium cepa L. bulbs in a second-degree burn wound model in Holtzman rats

Background: The bulb of Allium cepa Linnaeus (onion) is used in traditional medicine as an antidiabetic, antioxidant, antihypertensive, anti-inflammatory, and antihyperlipidemic, among others. The lack of information or little knowledge about the effects of Allium cepa L. on skin lesions, specifically burn wounds, arouses interest in studying its effects on these skin disorders. Objective: This study assessed the wound healing activity of Allium cepa L. on second-degree burns induced in Holtzman rats. Method: Thirty-two albino rats were randomly distributed into four groups of 8 rats each, including the Healthy group, the Control group, the Experimental group (Allium cepa L.), and the Standard group (1% silver sulfadiazine). Burn wounds were induced, and topical treatments were performed daily for 21 days. The reduction of the burned body area (mm2) was determined during the experimental time. Albino rats were sacrificed with an excess of surgical anesthesia to obtain tissue samples for histopathological analysis. Results: Standard and experimental groups significantly reduced burned body area (p<0.01) compared to the control group. Histopathological studies showed hyperemic chorion in the Control group, fibroblasts, and collagen in the Standard group, and dermis composed of a reticular stratum of fibroblasts, collagen, and few blood vessels in the Experimental group. Conclusion: Allium cepa L. revealed wound-healing activity on burns induced in Holtzman rats and reduced the damage produced by burns.

Validation of a method employing liquid chromatography to identify and quantify glycomacropeptide of casein in raw milk

BACKGROUND: The information on official testing methods, or regulatory methods in Colombia to test whey in milk is limited; this restriction of information goes against the possibility of mitigating the risk of food fraud. OBJECTIVES: The validation of an HPLC method to determine casein glycomacropeptide (c-GMP), a protein that countries such as Brazil, Spain, and Ecuador have used as an indicator of raw milk adulteration with whey, was carried out. METHODS: A 10mL sample of raw milk is precipitated with 24% TCA using ultrasound, a process followed by filtration. The collected fraction ensured the separation of c-GMP and then injected into the liquid chromatography. RESULTS: A 30 minutes analysis allowed the determination of c-GMP with a retention time of 12.9 ± 0.5 minutes. The performance characteristics method in the validation exercise were: recovery percentage 99.97%, linearity R2> 0.95; % RSD accuracy <5.3%. CONCLUSION, the method exhibits desirable attributes for the intended purpose.

Iodine deficiency in women of childbearing age in Brazil: systematic review and meta-analysis

Background: Despite current policies of salt iodination, iodine deficiency is still a global public health problem, especially in women. So far, conflicting evidence has been suggested for the prevalence of iodine deficiency in Brazil. Objective: To estimate the prevalence of iodine deficiency and associated factors in women of childbearing age in Brazil. Methods: A systematic review was conducted using databases (PubMed, LILACS, WHO, Scopus, and Capes’ dissertation and thesis), from inception to May 2020. Meta-analyses of proportions were performed using the variance inverse for the fixed model. Reporting and methodological quality were assessed using the Joanna Briggs Institute tool to prevalence studies. Results: Our review identified seven studies published between 2002 e 2017, including 1354 participants, especially pregnant women. All studies presented at least one quality limitation, mainly regarding the sampling method (i.e., convenience) and small sample size. The prevalence of iodine deficiency ranged among studies from 16% to 62%. In contrast, the meta-analysis identified a mean prevalence of 40% (95% confidence interval, CI 37%-43%) for pregnant women and 13% (95% CI 4%-24%) for non-pregnant women. Cumulative meta-analysis suggests a tendency of higher iodine deficiency prevalence from 2018 in pregnant women. Conclusions: Although this systematic review identified studies with poor methodological and reporting quality, a high prevalence of iodine deficiency was identified in pregnant women, reinforcing the importance of national nutritional policies for monitoring iodine status in this population. Future studies should consider random probabilistic sampling, appropriate sample size, and pre-defined subgroup analysis to adequately inform the prevalence of iodine deficiency and associated factors in women of childbearing age and support health policies.

Voltammetric Determination of Ascorbic Acid in Pharmaceutical Formulations Using Modified Iodine-Coated Platinum Electrode

Background: Despite the high reactivity of the platinum electrode, the iodine-coated platinum electrode shows obvious inertness toward adsorption and surface processes. For that, iodine-coated platinum electrodes accommodate themselves to interesting voltammetric applications. Objectives: This study reports using the modified iodine-coated polycrystalline platinum electrode as a voltammetric sensor for ascorbic acid determination in pharmaceutical formulations. Methods: The developed voltammetric method based on recording cyclic voltammograms of ascorbic acid at iodine-coated electrode The optimized experimental parameters for the determination of ascorbic acid were using 0.1 M KCl as a supporting electrolyte with a scan rate of 50mV/s. Results: The anodic peak related to ascorbic acid oxidation was centered at nearly 0.28V. An excellent and extended linear dependence of the oxidative peak current on the concentration of ascorbic acid was observed in the range 2.84x10-3 - 5.68 mM. The limit of detection (LOD) and limit of quantitation (LOQ) were 1.0 µM and 3.01 µM, respectively, attesting to the method’s sensitivity. The investigation for the effect of potential interference from multivitamin tablet ingredients (vitamins B1, B6, B12, folic acid, citric acid, sucrose, glucose, and zinc) indicated specific selectivity toward ascorbic acid and the absence of any electrochemical response toward these components. Recovery results in the range 98.93±2.78 - 99.98±5.20 for spiked standard ascorbic acid in pharmaceutical formulations further confirmed the potential applicability of the developed method for the determination of ascorbic acid in real samples. Conclusions: The developed method was successfully applied to the analysis of ascorbic acid (vitamin C), and the obtained results were in good agreement with the labeled values; besides, the statistical tests indicated no significant difference at p=0.05 with a 95% confidence level.

In vitro antimicrobial activity of Caesalpinia coriaria (Jacq.) Willd extracts on Streptococcus pyogenes and Candida albicans

Background: “Dividivi” Caesalpinia coriaria (Jacq.) Willd fruits are traditionally used by the Wayuú community in La Guajira (Colombia) to treat oral and skin cavity diseases caused by bacteria and fungi. Streptococcus pyogenes is a gram-positive cocci of group A (beta-hemolytic) that is the cause of pharyngeal disease, scarlet fever, cellulitis, erysipelas, or toxic shock-like syndrome. Alternatively, Candida albicans is a yeast-like fungus that is a normal flora of the digestive tract, vagina, or skin folds; it has been known to be the root cause of opportunistic diseases such as diaper rash, oral and esophagus thrush, or vulvovaginitis. Objective: This study evaluated the antimicrobial activity of methanolic and ethanolic extracts of C. coriaria (Jacq.) Willd dry fruits on S. pyogenes ATCC 12384 and C. albicans ATTC 14053. Method: C. coriaria extracts were obtained from the Soxhlet method using two solvents (methanol and ethanol 98%) prepared from pulverized fruits. A phytochemical test and an antimicrobial activity assay were performed using the obtained extracts and tested using S. pyogenes ATCC 12384 and C. albicans ATTC 14053 strains. Results: A phytochemical profile was performed, examining the presence of bioactive metabolites (tannins, alkaloids, glycosides, saponins, and anthraquinones) from each extract. Antimicrobial susceptibility tests showed that the ethanolic extract inhibited S. pyogenes ATCC 12384, causing inhibition halos of 14.1 ± 0.1 mm and a Minimum Inhibitory Concentration (MIC) of 172 mg/ml, and C. albicans test shows inhibition halos of 16.1 ± 0.2 mm and MIC of 212 mg/ml. Additionally, the methanolic extract inhibited S. pyogenes with inhibition halos of 15.2 ± 0.2 mm and MIC of 152 mg/ml; no inhibitory effect was observed on C. albicans. Conclusion: This study revealed that C. coriaria has an antimicrobial effect on the tested species opening the field of its possible use as a therapeutic agent.

Consumption of osmo-dehydrated Andean Berry (Vaccinium meridionale Swartz) decreases levels of pro-inflammatory biomarkers of overweight and obese adults

Background: A Body Mass Index (BMI) greater than 24.9 Kg/m2 promotes chronic inflammation due to increased secretion of pro-inflammatory adipokines. Consuming fruits rich in bioactive compounds such as berries is a promising strategy to counteract this effect. Objectives: Determine the effect of osmo-dehydrated Andean Berry consumption on inflammatory biomarkers (TNF-α, IL-6, IL-1β, and adiponectin) and plasma antioxidant capacity in overweight and obese adults after 21 days. Methods: Andean Berry was osmo-dehydrated in 70% sucrose syrup. Antioxidant activity, proximal composition, phenolic content, microbiological analysis, and sensory analysis of the product were determined. Twenty-five obese and overweight subjects consumed 35g of osmo-dehydrated berry for 21 days. Inflammatory biomarkers and antioxidant capacity in plasma were evaluated at the beginning and end of the study. Results: Osmo-dehydrated Andean Berry presented a total phenolic content of 692.7 ± 47.4 mg Gallic Acid Equivalents/100 g. All biomarkers evaluated in the subjects showed statistically significant differences (p> 0.05), except for CRP, before and after the study. IL-6 presented the more significant reduction among all pro-inflammatory adipokines with an effect size of 18.4 Conclusions: Regular consumption of osmo-dehydrated Andean Berry contributes to decreasing pro-inflammatory biomarkers and improves the plasma antioxidant capacity of overweight and obese adults.