Utilizing Carbon Dots Derived from Waste Face Masks for Pentachlorophenol Detection Dilek Öztürk, Mahmut Durmuş Journal of Fluorescence, 2025 Pentachlorophenol is a very toxic chemical that is used as a pesticide, fungicide, herbicide, wood preservative, etc., and it should be monitored in terms of human health and environmental production. Another environmental problem is the increase in the use of facemasks, especially during the COVID-19 pandemic. This study provides a value added chemicals to sustainability of recycling process. Fluorescent carbon dots (CDs) were synthesized from waste facemasks and investigated their fluorescence sensor performances. UV-Vis and fluorescence spectra of the synthesized carbon dots were recorded in different organic solvents. The sensor properties of these carbon dots against pesticides were investigated, and a ‘turn-off’ response was observed toward pentachlorophenol. The limit of detection was found 8.5 µM in the linear range from 43.3 µM to 375 µM. This study showed that waste plastics such as facemasks can be recycled to obtain carbon dots, which are used in different technological areas such as photocatalysis, bioimaging, etc., as well as in sensors. Graphical Abstract
N-Doped carbon quantum dot–based ratiometric fluorescent nanosensor platforms for detection of gastric cancer-associated Helicobacter pylori genes Dilek Öztürk, Mahmut Durmuş Microchimica Acta, 2025 Carbon quantum dot (CQD)–based fluorescent nanosensor platforms were developed using gastric cancer-associated Heliobacter pylori (H. pylori) genes. N-doped CQDs were synthesized using two different organic acids (citric acid and malic acid) and ethylenediamine by the microwave method. The photophysical and photochemical properties of the synthesized CQDs were investigated by ultraviolet–visible, fluorescence, and Fourier-transform infrared spectra. The surface of the synthesized N-doped CQDs was conjugated with single-stranded DNA (ssDNA), which is specific for gastric cancer. Ethidium bromide, a selective dye, shows enhanced fluorescence intensity upon intercalating with DNA. In the blue-emissive CQD-ssDNA nanoprobe system, the fluorescence intensity was quenched by ethidium bromide due to Förster resonance energy transfer (FRET) processes. When complementary ssDNA was introduced, the ethidium bromide strongly intercalated with the newly formed double-stranded DNA, shifting to a red emission. Using this ratiometric system, the detection method was improved for gastric cancer–associated genes, achieving a limit of detection (LOD) of 0.098 µM, within a concentration range 1.30 to 11.49 µM. Spike and recovery tests were also conducted to evaluate the precision of the presented method in synthetic saliva solutions, with recoveries ranging from 93.06% to 101.85% The performance of the nanosensors was compared using two different synthesized CQDs. Graphical abstract
Photophysicochemical and electrochemical properties of pyrene-BODIPY platforms İpek Ömeroğlu, Baybars Köksoy, Dilek Öztürk, Lubna Salah, Saad Maksheed, Mahmut Durmuş New Journal of Chemistry, 2024 The photochemical, photophysical, and electrochemical properties of novel BODIPY compounds substituted with iodine or pyrene groups at the 2-, 6-, or 8-positions (meso) were thoroughly investigated.
Click Chemistry for Nanoparticle-Modification Dilek Öztürk, Mahmut Durmuş Click Chemistry Volume 2 Emerging Applications and Challenges, 2024 Nanotechnology is a new class of material science that has been given great attention by scientists. Nanoparticle materials are formed by the combination of chemistry, materials, and nanotechnology sciences. Nanomaterials find different applications area in almost all science and industrial areas such as food, machines, electronics, chemistry, drugs, etc. One of the most important reasons for the use of nanomaterials in many areas is the ease of chemical modification of the surface of these materials. In chemistry, it is possible to produce a new molecule and modifications by making different combinations with many molecules in the presence of suitable catalysts. “Click” chemistry is one of the significant chemical reactions for the chemical modification of nanomaterials. It is a special reaction in which a series of chemical reactions occur together producing a highly efficient product and minimal by-products. “Click” chemistry, awarded the Nobel Prize in Chemistry in 2022, is widely used in bioconjugation, surface modification, and materials science. In this chapter, information about “click” chemistry methods used in the modification of nanoparticles will be discussed.
“Click” Chemistry for Biosensors İpek Ömeroğlu, Dilek Öztürk, Mahmut Durmuş Click Chemistry Volume 2 Emerging Applications and Challenges, 2024 “Click” chemistry is used for molecular fitting in the widest possible range of applications impacts practically all branches of chemical science. It is a series of chemical reactions that efficiently and rapidly combine small units with heteroatom bonds to form stable new substances. This chemical reaction is mostly used in the modification of biomolecules because it provides advantages such as mild reaction conditions and high synthesis efficiency, fast reaction, and high selectivity. Biosensors are based on the interaction between a molecular probe with a specific affinity and the target analyte. Also, they can be classified as electrochemical, optical, piezoelectric, thermal, etc. according to the measurement method. Biosensors are miniature devices that can replace heavy, difficult-to-use, special, and complex devices that require specialists in industry and clinical studies according to the advancement of technology. Multifunctional materials developed with the advantages of “click” chemistry are also widely used as biosensors. The materials used in biosensors are modified to increase their selectivity and specificity using the “click” chemistry. In this chapter, information about the developed biosensor materials prepared by “click” chemistry and their responses and functionalities will be discussed.
