Lactate is one of the major biomarkers to assess the physical fitness of human in clinical or sports medicine. The proper and well‐timed lactate determination can avoid some exigent conditions including hemorrhage, respiratory distress, sepsis, and hypoxia. Therefore, rapid, facile, selective, and reliable detection of lactate have gained appreciation lately. Among the various lactate detection methods, electrochemical method is the most rapid, convenient, and sensitive technique. Specifically, nanomaterial‐based nonenzymatic electrochemical lactate sensors are much desirable to solve the demerits and stability issues of enzymatic lactate sensors. Numerous materials including metal and metal oxide nanoparticles, metal–organic frameworks, molecularly imprinted polymers, and carbons were used as electrocatalysts to achieve highly sensitive lactate sensors. This present review mainly focuses on the recent developments of these materials for enzyme‐free lactate oxidation and the future prospective of electrode modification catalysts for lactate sensors.
Granzyme B (GzmB) is a cytotoxic protease found in the granules of natural killer (NK) cells and cytotoxic T lymphocytes (CTLs), which participates in inducing apoptosis of target cells for NK cells and cytotoxic CD8+ lymphocytes [1]. GzmB is the major effector of the CTLs and NK cells in its killing attack on cancer cells, although the level of GzmB expression and its cytotoxic potential decrease significantly in the presence of cancer. This decrement is due to a ‘pro-cancer’ environment, where the cancer cells secrete soluble mediators that could inhibit and thus contribute to the decreased GzmB by CD8+ T cells and a reduction in their ability to cause apoptosis of the cancer cells. Once GzmB is secreted from cytotoxic cells, it can be discovered in two different host compartments, namely inside the target cell or extracellularly [2]. Due to this, the change of GzmB level in blood plasma may serve as indication of the patient’s cancer cure progress. Hence, we developed a disposable amperometric GzmB sensor for the blood plasma samples. In developing a robust electrochemical sensing platform, an efficient device is required. To enhance the electrochemical response, catalytic nanoparticles can be used as the electrode material, particularly nanocomposites composed of functionalized conducting polymers. They have been well-thought-of as the candidate of electrode substrate materials for the electrochemical sensing platform due to their ability to augment the electrical conductivity, electron-transfer rate, mechanical strength, surface area, and binding affinity to a specific molecule [3]. Therefore, 3’-(2-aminopyrimidyl)-2,2’:5’,2’’-terthiophene (PATT) bearing an amine group was electro-polymerized onto gold nanoparticles (AuNPs) modified electrode. Then, the stabilized immobilization of antibody on the SPCE/AuNPs/pPATT layer was accomplished through the formation of an amide bond between amine groups of the polymer and carboxylic acid groups of the antibody. In this study, a disposable amperometric immunosensor composed of a sensing probe and a bioconjugate was developed for the detection of GzmB. The sensing probe was fabricated by immobilizing the GzmB monoclonal antibody (Ab1) on the polyPATT/AuNPs layer. The bioconjugate particle was synthesized by self-assembling the monomer mixture of 2,2:5,2-terthiophene-3-(p-benzoic acid) (TBA) and PATT onto AuNPs, then covalently bonding brilliant cresyl blue (BCB) on pTBA and GzmB polyclonal antibody (Ab2) on pPATT layer, respectively. The sensing layers were characterized using the surface analysis, cyclic voltammetry, impedance spectroscopy, and X-ray photoelectron spectroscopy. A redox peak of the bioconjugate (Ab2-SAM-BCB) in the presence of GzmB in the sample was observed at -0.35/-0.37 V, corresponding to the redox reaction of the redox indicator BCB. Optimization of experimental parameters were carried out in terms of temperature (35°C), pH (7.4), the concentration of antibody (300 μg/ml), applied potential (-0.38 (reduction)), and binding time (20 min). At the optimized conditions, the developed immunosensor showed a dynamic range from 3.0 to 50.0 pg/ml and from 50.0 to 1000.0 pg/ml in two slops, with a detection limit of 1.75 ± 0.14 pg/ml. Interference effect, stability, and reproducibility were also evaluated. Reliability of the proposed immunosensor was evaluated through comparison of the results among GzmB concentration of lung cancer patients before and after medicine treatment, and healthy volunteer using human blood plasma samples, where the low level of GzmB was present in the blood plasma of lung cancer patients before medicine treatment (10.50 ± 1.02 pg/ml), which slightly increased level in patients after medicine treatment (15.85 ± 1.99 pg/ml), and the significantly higher level was present in the normal healthy individual (39.62 ± 0.79 pg/ml). Conclusively, the progress of cancer before and after the cure of the patients has been evaluated through monitoring GzmB concentration in the blood plasma. [1] Kurschus, F.C., Jenne, D.E., 2010. Immuno. Rev. 235, 159-171. [2] Boivin, W.A., Cooper, D.M., Granville, D.J., 2009. Lab. Invest. 89, 1195-1220. [3] Naveen, M.H., Gurudatt, N.G., Shim, Y.-B., 2017. Appl. Mater. Today 9, 419–433.
Background: Low-dose computed tomography (LDCT) has improved the early detection of lung cancer.However, LDCT scans present several disadvantages, including the abundance of false-positive results, which lead to a high socioeconomic cost, psychological burden, and repeated exposure to radiation. Therefore, the identification of complementary biomarkers is needed to select high-risk individuals for LDCT. Here, we showed that granzyme B testing with the novel immunosensor has diagnostic value for identifying patients with lung cancer. Methods:We enrolled 44 patients with lung cancer and 51 health controls at Pusan National University Yangsan Hospital in Korea between March 2018 and September 2019. The immunosensor analyzed serum granzyme B levels, and their association with lung cancer detection was evaluated with machine learning models.Results: Serum granzyme B levels were assessed in samples from patients with lung cancer and healthy individuals. Granzyme B testing showed 100% sensitivity, 80% specificity, and an area under the curve of 0.938 for lung cancer detection. After combining granzyme B testing with clinical predictors such as age, smoking status, or pack-years, results from the five-fold cross-validation with random forest model improved diagnostic accuracy of 92.1%, with a sensitivity, specificity, and area under the curve of 92.0%, 92.1%, and 0.977, respectively.Conclusions: This feasibility study suggested that granzyme B may be utilized to detect lung cancer.
Bacillus subtilis is a bacterial contaminant widely discovered in laboratories and used in educational needs. Synthetic media are relatively expensive, which makes it difficult for microbiology laboratories to meet large-scale bacterial growth media demands. This has encouraged researchers to find alternative media with cheaper and easily available prices, namely Mung Beans, which are known to contain protein nutrients that are good for bacterial growth, which is as much as 24%. The purpose of this study was to determine the potential of mung beans’ alternative media as a medium for bacterial growth. This research is a descriptive study and the sample used is 1 tube of a pure isolate of Bacillus subtilis. The variable of this research is mung beans as an alternative medium for the growth of Bacillus subtilis. The results were obtained by observed macroscopically and microscopically, followed by a carbohydrate fermentation test and an IMViC test. Then showed that the colonies growing on the alternative medium of mung beans were in accordance with the characteristics of the colonies growing on Nutrient Agar medium (control), which indicated that these characteristics were Bacillus subtilis. Based on the research that has been done, it can be concluded that there is a qualitative growth of Bacillus subtilis in mung beans alternative media, which means that mung beans alternative media has the potential as a growth medium for Bacillus subtilis.
According to regulation number 722/MENKES/Per/IX/88 of the Minister of Health of the Republic of Indonesia, Rhodamine B is one of the dangerous dyes, and its use in food products is prohibited. Rhodamine B can cause adverse health effects including irritation, impaired liver function, and liver cancer. Although it has been banned, the use of Rhodamine B is still prevalent in the community's food supply, including shrimp paste. This can be observed in some of the shrimp pastes sold at the Ciroyom market in Bandung, which are bright red, uneven, and comprised of lumps. This study aims to determine the Rhodamine B content of shrimp paste sold at Ciroyom Market in Bandung, West Java, Indonesia. This research is descriptive in nature and employed a total sampling technique. Rhodamine B was analyzed in ten samples of commercially available red shrimp paste using a UV-Vis Spectrophotometer with a 565 nm wavelength. The results indicate that Rhodamine B was found in all samples, with concentrations ranging from 1.79 ppm to 3.999 ppm. Therefore, it can be concluded that widespread abuse of Rhodamine B in food ingredients persists among the residents of Bandung City, West Java, Indonesia.
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