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While the World Health Organization has declared the end of the SARS-CoV-2 public health emergency, studies related to corona viruses are still under course. As of 2024, the severity of COVID-19 has diminished with current treatments and vaccinations. However, individuals can still face severe complications, highlighting the importance of ongoing research into innovative treatments for current and future coronavirus-related diseases. This study approaches the mechanism of viral entrance into the host cells and the current evidence on the use of sulfhydryl groups for the COVID-19 treatment. Certain thiol drugs, a key contributor to inflammatory processes, exhibit both viral inhibition properties and the potential to regulate cellular oxidative stress by scavenging free radicals. Herein, we developed biocompatible thiol-functionalized carbon dots (CDs) and investigated the correlation between the number of thiols and pseudo-SARS-CoV-2 inhibition, reactive oxygen species (ROS) scavenging, and anti-inflammatory response. The free-radical scavenging experiment and the ROS cellular assay indicate that thiolated CDs serve as effective reducing agents and potential regulators of cellular oxidative stress. The CDs also demonstrated good cell viability alongside significant antiviral capabilities, with inhibition levels up to 60.4%. Furthermore, the flow cytometry results suggest that in an inflammatory environment, the presence of thiolated CDs promotes an anti-inflammatory response. Overall, the results demonstrate a strong correlation between the number of thiols and the increased efficacy observed across experiments, presenting thiolated CDs as promising candidates to prevent and treat COVID-19 infection.

In two phase 3 trials for first-line therapy in adults with HIV-1, doravirine showed non-inferior efficacy, a favourable safety profile, and a superior lipid profile to darunavir and efavirenz through to 48 and 96 weeks. Here we report 192-week results from both studies.

Graphitic carbon nitride (g-C3N4) can trigger the photocatalytic partial oxidation of HMF to produce 2,5-diformylfuran (DFF), yet limitations still exist in improving its performance. Herein, Pd nanoparticles were deposited over thermally exfoliated g-C3N4(Ex-g-C3N4) to boost its activity. Graphitic sheets with a thickness of ∼1.2–1.6 nm were obtained and then decorated with spherical Pd nanoparticles with a size of 2.0–2.5 nm. A maximum concentration of DFF (148.5 ± 4.9 μM) was obtained over the Ex-g-C3N4/Pd with 6% (w/w) deposited Pd with a product selectivity toward DFF of 42.9 ± 0.6%. Our results revealed that the extent of DFF production is directly proportional to the Pd content until 6% (w/w), and beyond that it declines. Trapping experiments and EPR analysis showed that singlet oxygen is the dominant species responsible for the selective oxidation of HMF to DFF. Our mechanistic study suggests that triplet excitons are generated via intersystem crossing, which then react with molecular oxygen to produce singlet oxygen. Furthermore, intrinsic reaction coordinate and energy barrier calculations indicated that the reaction is thermodynamically allowable. Our study reveals that singlet oxygen is capable of abstracting hydrogen atoms from the α carbon and hydroxyl moiety of HMF to eventually produce DFF. This work provides deep insight into the benefits of exploiting Pd nanoparticles to enhance production of singlet oxygen over g-C3N4, which in turn enhances the production of DFF.

In recent years, many researchers have struggled to obtain carbon dots (CDs) that possess strong photoluminescence in the red region of light. Success in this area has been limited, although the past few years have brought several promising reports on this topic. The most successful efforts in this area still seem to struggle from a lack of dispersibility/reduced emission in water. This work endeavors to understand the formation process of CDs that do not possess strong performance in an aqueous environment and to improve their capabilities in bioimaging. o-Phenylenediamine (o-PDA) is used along with various precursors in several different solvents (varying acidic and oxidative strengths) to understand the formation process behind the structure leading to red emission that is sensitive to water. These results showed that the combination of acid properties and oxidation is essential for this process, and the important reactions are oligomerization of o-PDA and the crosslinking of these oligomers to form aromatic structural segments of CDs. These CDs are shown to be capable of quantitatively detecting water in organic solvents. Additionally, we have shown that conjugation with transferrin remarkably enhances the biocompatibility of these CDs. Transferrin-conjugated CDs with better biocompatibility were applied to bioimaging studies of neuroblastoma cell lines with N-mycand non-N-mycgene amplification, for the first time. Furthermore, CDs showed versatile bioimaging capability toward a highly aggressive neuroblastoma subgroup of tumors. The importance of creating red-emissive CDs has been well established, and this work is an important step toward understanding their formation and realizing their use in biological systems.

This work investigates the physicochemical properties of mixed stearic acid (HSt)/phenylalanine dehydrogenase enzyme (PheDH) Langmuir films and their immobilization onto solid supports as Langmuir–Blodgett (LB) films. PheDH from the aqueous subphase enters the surfactant matrix up to an exclusion surface pressure of 25.3 mN/m, leading to the formation of stable and highly condensed mixed Langmuir monolayers. Hydrophobic interactions between the enzyme and HSt nonpolar groups tuned the secondary structure of PheDH, evidenced by the presence of β-sheet structures as demonstrated by infrared and circular dichroism spectra. The floating monolayers were successfully transferred to solid quartz supports, yielding Y-type LB films, and then characterized employing fluorescence, circular dichroism, and microscopic techniques, which indicated that PheDH was co-immobilized with HSt proportionally to the number of transferred layers. The enzyme fluidized the HSt monolayers, reducing their maximum dipoles when condensed to their maximum, and disorganized the alkyl chains of the fatty acid, as detected with infrared spectroscopy. The stability of the mixed floating monolayers enabled their transfer to solid supports as LB films, which is important for producing optical and electrochemical sensors for phenylalanine whose molecular architecture can be controlled with precision.

Carbon dots (CDs) are a novel class of nanoparticles with excellent properties. The development of CDs involves versatile synthesis, characterization, and various applications. However, the importance of surface chemistry of CDs, especially in applications, is often underestimated. In fact, the study of the surface chemistry of CDs is of great significance in the explanation of the unique properties of CDs as well as the pursuit of potential applications. In this feature article, we do not only introduce the development of CDs in our group but also highlight their applications where surface chemistry plays a critical role.

Carbon dots (CDs) are zero-dimensional carbon-based spherical nanoparticles with diameters less than 10 nm. Here, we report for the first time CDs forming stable Langmuir monolayers at the air–subphase interface. Langmuir monolayers are of great interest both fundamentally to study the interactions at the interfaces and for many applications such as the development of sensors. However, CDs usually do not form Langmuir monolayers because of their highly hydrophilic nature. In this study, amphiphilic CDs were prepared through hydrothermal carbonization using saccharides as the precursors. The surface chemistry behavior and optical properties of CDs at the air–subphase interface were studied. CDs derived from saccharides consistently formed stable Langmuir monolayers which show all essential phases, namely, gas, liquid-expanded, liquid-condensed, and solid phases. The compression–decompression cycle method showed minimum hysteresis (4.3%), confirming the retaining capacity of the CDs as a monolayer. Limiting CD areas from surface pressure–area isotherm at the air–subphase interface were used to calculate the average diameter of the CDs at the air–subphase interface. UV/vis absorption spectra of CDs dispersed in water and in Langmuir monolayers had the same bands in the UV region. The intensity of the UV/vis absorption increases with increasing surface pressure at the air–subphase interface. Interestingly, photoluminescence (PL) of the Langmuir monolayer of CDs was excitation-independent, whereas the same CDs had excitation-dependent PL when dispersed in water.

Fumonisin B1 (FB1), the most abundant component of the fumonisin family, is highly responsible for fungal infections. In this paper, our main aim is to study the surface chemistry and spectroscopic properties of the FB1 molecule and observe the impact of green LED light on the FB1 Langmuir monolayer. From the surface chemistry and spectroscopic studies, we found that the FB1 molecule forms a self-assembled Langmuir monolayer which is sufficient to mimic its interaction with the corneal tissues. The irradiation of green LED light on the FB1 Langmuir monolayer showed the degradation of the FB1 when compared to that in the absence of light. This observation reveals that FB1 molecules lose their tendency to stay as a Langmuir monolayer. The degradation observed on the interface was compared with the bulk phase of FB1. The bulk phase observation also indicated the degradation tendency which reinforced the observed interfacial property of FB1.

Carbon dots have often been studied to investigate their unique optical properties such as excitation wavelength-independence emission. Carbon dots have also been shown to undergo electron transfer in different situations. This study endeavors to investigate the properties of carbon dots’ photoluminescence and electron transfer. Herein, the preparation and characterization of carbon dots which exhibit long wavelength photoluminescence has been reported. These carbon dots exhibit quenching when exposed to metal ions in proportion to the reduction potential of the metal, which experimental evidence has shown for the first time. This property of metal ion reduction potential-dependent quenching has been studied to show the collisional electron transfer from amine groups in carbon dots to the metal ions. Therefore, the photoluminescence in these carbon dots is directly related to organic functional groups on the surface of the carbon dots.

In contrast to the recent immense attention in carbon nitride quantum dots (CNQDs) as a heteroatom-doped carbon quantum dot (CQD), their biomedical applications have not been thoroughly investigated. Targeted cancer therapy is a prominently researched area in the biomedical field. Here, the ability of CNQDs as a selective bioimaging nanomaterial was investigated to assist targeted cancer therapy. CNQDs were first synthesized using four different precursor sets involving urea derivatives, and the characteristics were compared to select the best candidate material for bioapplications. Characterization techniques such as UV–vis, luminescence, X-ray photoelectron spectroscopy, nuclear magnetic resonance spectroscopy, and transmission electron microscopy were used. These CNQDs were analyzed in in vitrostudies of bioimaging and labeling using pediatric glioma cells (SJGBM2) for possible selective biolabeling and nanodistribution inside the cell membrane. The in vitrocellular studies were conducted under long-wavelength emission without the interference of blue autofluorescence. Thus, excitation-dependent emission of CNQDs was proved to be advantageous. Importantly, CNQDs selectively entered SJGBM2 tumor cells, while it did not disperse into normal human embryonic kidney cells (HEK293). The distribution studies in the cell cytoplasm indicated that CNQDs dispersed into lysosomes within approximately 6 h after the incubation. The CNQDs exhibited great potential as a possible nanomaterial in selective bioimaging and drug delivery for targeted cancer therapy.

Cancers and many other diseases, such as hepatocellular carcinoma (HCC) and cardiovascular diseases (CVD), have threatened human lives for centuries. Therefore, a novel technique for such disease prediction is in an urgent demand for timely treatment. Biomarkers, alpha-L-fucosidase (AFU) for HCC and cardiac troponin I (cTnI) for CVD, have proven to be essential in the role of disease detection. Herein, we report on an ultrasensitive plasmonic biosensor that converts plasmonic absorption to electrical current in order to detect AFU and cTnI using whole human blood in a real-time and parallel fashion. The detection limit was calculated to be 0.016 U/L for AFU and 0.015 ng/mL for cTnI, respectively. Combined with the versatility of the strategies for different biomarkers, these results demonstrate that the developed biosensor exhibits a promising application for the prediction of cancers and many other diseases.