Silver-doped hydroxyapatite for formaldehyde determination by digital-image colorimetry

Electrochemical and Optical Sensors for the Detection of Chemical Carcinogens Causing Leukemia

The incidence and mortality due to neoplastic diseases have shown an increasing tendency over the years. Based on GLOBOCAN 2020 published by the International Agency for Research on Cancer (IARC), leukemias are the thirteenth most commonly diagnosed cancer in the world, with 78.6% of leukemia cases diagnosed in countries with a very high or high Human Development Index (HDI). Carcinogenesis is a complex process initiated by a mutation in DNA that may be caused by chemical carcinogens present in polluted environments and human diet. The IARC has identified 122 human carcinogens, e.g., benzene, formaldehyde, pentachlorophenol, and 93 probable human carcinogens, e.g., styrene, diazinone. The aim of the following review is to present the chemical carcinogens involved or likely to be involved in the pathogenesis of leukemia and to summarize the latest reports on the possibility of detecting these compounds in the environment or food with the use of electrochemical sensors.

Cost-effective formaldehyde assay platform for multi-sample analysis in one run based on pervaporation coupled with a biodegradable sensor and a simple heat control unit

A novel, cost-effective platform using a biodegradable sensor and a simple heat control unit was proposed for multi-sample formaldehyde (FA) assay in one run based on pervaporation. The biodegradable sensor was a composite starch gel attached to paper and immobilized with a mixture of color agents of modified 4-amino-3-hydrazino-5-mercapto-1,2,4-triazol (AHMT). The sensor was situated on the cap of a vial that served for pervaporation. Two types of heat control units were specially designed using the concepts of aluminum block and water bath heating. With these two designs, multi-sample assays together with standard calibration could be performed in the same run under the same conditions. An FA solution was placed in the vial of the pervaporation unit. After a heating period, FA vapor would change the color of the sensor to purple due to the reaction between AHMT and FA. As a result, the color intensity was proportional to the FA concentration. The change of the color (green or G intensity) was monitored using a smartphone camera and image processing software. Factors affecting the sensitivity of the assay, pervaporation time, pervaporation temperature, FA solution volume, and humidity, were studied. Under the chosen condition, the developed procedure, with a calibration of G intensity = 7.93[FA] + 198, R² = 0.98, was applied to analyze real samples of seafood and mushrooms available in local markets in Thailand. As there were 24 pervaporation units in the proposed platform, 5 working standards and 9 samples with duplicates could be included in a 1-run assay either in the laboratory or on-site. The developed assay offers green chemical analysis with a simple, cost-effective approach. This serves the UN-SDGs of #2, #3, #7, #10, and #12.

Green Synthesis of Antibacterial Nanocomposite of Silver Nanoparticle-Doped Hydroxyapatite Utilizing Curcuma longa Leaf Extract and Land Snail (Achatina fulica) Shell Waste

Preparation of green synthesized silver nanoparticle (AgNPs)-doped hydroxyapatite (Ag/HA) utilizing Curcuma longa leaf extract and land snail (Achatina fulica) shell waste was performed. Physicochemical characteristics and antibacterial activity of Ag/HA composite as a function of Ag content was studied. Instrumental analysis such as XRD, SEM-EDX, TEM, and XPS were employed to characterize the nanocomposites. The physicochemical study revealed the maintained porous structure of HA after Ag immobilization, and from TEM analyses, it was found that the distributed spherical particles are associated with the dispersed Ag and have a particle diameter of around 5-25 nm. Antibacterial activity of the nanocomposite was evaluated against Escherichia coli, Staphylococcus aureus, Kliebsiella, pneumonia, and Streptococcus pyogenes. The results showed that the varied Ag content (1.0; 1.6; and 2.4% wt) influenced the nanoparticle distribution in the nanocomposite and enhanced the antibacterial feature.

A novel signal-on fluorometric sensor based on metal ion-mediated carbon dots for formaldehyde determination and lysosome-targeted bioimaging

Preparation of Ag-M-NSCDs for the fluorometric detection of formaldehyde and lysosome-targeted bioimaging.