Dual mode detection and sunlight-driven photocatalytic degradation of tetracycline with tailor-made N-doped carbon dots.

Carbon dots have emerged as one of the most promising materials with various potential applications derived from their unique photophysical and chemical properties. The present work investigates the electrochemical and photochemical properties of one-pot synthesized carbon dots for environmental sustainability. Facile microwave-assisted pyrolysis of urea and glucose yielded nitrogen doped carbon dots (N-doped carbon dots) with blue fluorescence and a quantum yield of 14.9%. As synthesized N- doped carbon dot had intense fluorescence, stability, water solubility, and biocompatibility. In the sensing studies, N-doped carbon dots appeared as a dual sensor for drug tetracycline with excellent sensitivity and selectivity. Beyond sense, the carbon dots have the potential to act as a photocatalyst for the degradation of tetracycline. Further, N-doped carbon dot could bring exhaustive degradation of tetracycline (>95%) within 10 min in the absence of any additives. This is the first time report on the utilization of raw non-metal doped carbon dots as a photocatalyst for the degradation of tetracycline.

Biomass-derived carbon dots as a sensitive and selective dual detection platform for fluoroquinolones and tetracyclines.

A novel carbon dot (CD) was synthesized through the facile and simple hydrothermal method from Curcuma amada, as the precursor for the first time. These CDs with an average diameter of 4.6 nm display blue fluorescence, with excitation/emission maxima at 360/445 nm and a quantum yield of 14.1%. It exhibited high stability under different conditions and was characterized using various techniques. These CDs can be employed as a dual-sensing platform to detect tetracyclines and fluoroquinolones, two antibiotic classes. Even though antibiotics are regarded as an inevitable commodity, overuse and improper management of discarded antibiotics pose a severe threat to the environment. Herein, we developed a dual-sensing, biocompatible sensor with high selectivity and sensitivity to detect antibiotics. CD was employed as a fluorescence probe and detected tetracycline and fluoroquinolone antibiotic through inner filter effect-based fluorescence quenching and hydrogen bonding-based enhancement process, respectively. The linear range was 0-16 µM and the detection limit was 33 nM for tetracycline and 2 nM for fluoroquinolone antibiotic. As an electrochemical probe, CD selectively detected tetracycline with a lower detection limit of 0.5 nM over a linear range of 0-16 µM. Using both methods, a real sample analysis of the developed sensor exhibited accurate reliability and precision.

Carrageenan-based sustainable biomaterials for intelligent food packaging: A review.

This article explores the use of carrageenan-based biomaterials in developing sustainable and efficient intelligent food packaging solutions. The research in this field has seen a notable surge, evident from >1000 entries in databases such as Web of Science, PubMed and Science Direct between 2018 and 2023. Various film preparation techniques are explored, including solvent casting, layer-by-layer (LbL) assembly, and electrospinning. Solvent casting is commonly used to incorporate active compounds, while LbL assembly and electrospinning are favored for enhancing mechanical properties and solubility. Carrageenan's film-forming characteristics enable the production of transparent films, ideal for indicator films that facilitate visual inspection for color changes indicative of pH variations, crucial for detecting food spoilage. Surface properties can be modified using additives like plant extracts to regulate moisture interaction, affecting shelf life and food safety. These materials' antioxidant and antimicrobial attributes are highlighted, demonstrating their efficacy against pathogens such as E. coli.

Effect of green synthesized nano-titanium synthesized from Trachyspermum ammi extract on seed germination of Vigna radiate.

The current work investigates the conditional influence on Vigna radiate seed germination in vitro and in vivo using the green chemistry approach for the manufacture of titanium dioxide nanoparticles (TiO2 NPs) from seed extract of Trachyspermum ammi (T. ammi). Ultraviolet spectroscopy (UV-Vis), Fourier transform infrared spectroscopy (FTIR), Transmission electron microscopy (TEM), and X-ray diffraction (XRD) were used to analyze the TiO2 NPs produced. The crystalline nature of TiO2 NP was revealed by XRD data, and TEM investigation revealed an irregularity in TiO2 NP shape with a size of 17.5 nm. UV absorbance at 315 nm for the TiO2 NPs was observed using Ultraviolet-visible spectrophotometer. The antioxidant potential of the synthesized nanoparticle was discovered to be good. In case of seed germination studies, six concentrations (25, 50 100, 150, 200, and 250 µg mL- 1) of TiO2 NPs were examined along with the control on Vigna radiata seeds. Germination parameters such as seed vigor index (SVI), germination percentage (GP), germination value (GV) root length (RL) and shoot length (SL) of the Vigna radiata seedlings were observed and results revealed that the green synthesized TiO2 NPs were significantly improved. The results indicated that the TiO2 NP affected the plant growth more specifically at lower concentration (50 µg mL-1) of TiO2 NPs. Overall, the findings of this present study stipulated that the green TiO2 NP production can enhance the growth of Vigna radiate under in vitro and in vivo conditions.

Green synthesis of titanium dioxide nanoparticles using plant biomass and their applications- A review.

Biosynthesized nanoparticles have sparked a lot of interest as rapidly growing classes of materials for different applications. Plants are considered to be one of the most suitable sources for Green synthesis (GS) as they follow the environment-friendly route of biosynthesis of nanoparticles (NPs). This article focuses on the excavation of Titanium dioxide (TiO2) NP from different parts of plants belonging to a distinct classification of taxonomic groups. During the process of biological synthesis of titanium NPs from plants, the extract derived from plant sources such as from root, stem, leaves, seeds, flowers, and latex possesses phytocompounds that tend to serve as both capping as well as reducing agents. TiO2NP is one of the most commonly used engineered nanomaterials in nanotechnology-based consumer products. This article will provide an overview of the GS and characterization of TiO2NPs from plant extracts of different taxonomic groups. Lastly, this review summarizes the current applications of TiO2NPs.

Restraint stress fails to modulate cutaneous hypersensitivity responses in mice lacking the adenosine A1 receptor.

Psychological stress has long been associated with effects on immune function and disease. In particular, differential effects of acute and chronic stress on skin immunity occur in the rodent restraint stress model, with acute stress enhancing and chronic stress suppressing cutaneous hypersensitivity. Extracellular levels of adenosine are known to modulate diverse biological activities in the CNS and peripheral tissues and serve an important protective function against physiological stressors such as inflammation and ischemia. In this study, we utilized the restraint stress model and the skin sensitizer dinitrofluorobezene to test the hypothesis that perceived stress influences contact hypersensitivity through an adenosine A(1) receptor-mediated mechanism. We subjected hapten-sensitized A(1) receptor knockout (A1 KO) mice and their wild-type (WT) littermates to either acute (2.5 h) or chronic (5 h daily × 4 weeks) restraint stress, followed by hapten re-challenge of the pinna. Daily measurements of the resulting pinna swellings from each group were compared to reactions in non-stressed controls. In WT mice, pinna swelling was augmented in acutely stressed mice and suppressed in the chronically stressed group. In contrast, contact hypersensitivity responses in the A1 KO mice failed to be affected by either acute or chronic stress. Absence of the adenosine A(1) receptor did not affect levels of plasma corticosterone or urine catecholamines under these stressful conditions but did lead to reduced numbers of circulating neutrophil granulocytes compared to stressed WT animals. These results suggest that the adenosine A(1) receptor pathway plays a role in the process by which perceived psychological stress influences the contact hypersensitivity response.

The anergic state in sarcoidosis is associated with diminished dendritic cell function.

Sarcoidosis is a chronic inflammatory disease of unknown cause, characterized by granuloma formation similar to tuberculosis, but without clear evidence of a microbial infection. Because sarcoidosis is linked with clinical anergy and other evidence of diminished cellular immunity, we hypothesized that decreased skin delayed-type hypersensitivity (DTH) responses to recall Ags in affected individuals would be associated with decreased function of their blood dendritic cells (DCs). Our study involved ex vivo isolation, phenotyping, and functional testing of myeloid DCs (mDCs), plasmacytoid DCs, and T lymphocytes from blood of normal healthy volunteers and sarcoidosis subjects with active, untreated pulmonary disease. We found mDC function in the allogeneic MLR directly corresponded to the magnitude of skin DTH reactions to recall Ags in both sarcoidosis subjects and normal volunteers. However, both of these outcomes were significantly decreased in the sarcoidosis group. Diminished mDC function occurred despite up-regulated costimulatory and maturation markers. Clinical relevance is suggested by the inverse relationship between both mDC allogeneic responses and skin DTH responses with clinical disease severity as measured by chest radiograms. Because granulomas form when cellular immunity fails to clear antigenic stimuli, attenuated mDC function in sarcoidosis may contribute to susceptibility and persistence of the chronic inflammation characteristic of this disease.

Neurotoxic prostaglandin J2 enhances cyclooxygenase-2 expression in neuronal cells through the p38MAPK pathway: a death wish?

The role of the proinflammatory and inducible form of cyclooxygenases (COX-2) in neurodegeneration is not well defined. Some of its metabolic products, such as prostaglandins (PG) of the J2 series, are known to be neurotoxic. Here we demonstrate that PGJ2 enhances COX-2 gene expression without elevating COX-1 levels in neuronal cells. PGJ2 also increased PGE2 production, establishing that the de novo synthesized COX-2 is enzymatically active. PGJ2 derivatives, such as 15d-PGJ2, are known activators of PPARgamma, a nuclear receptor that activates gene expression. However, the selective PPARgamma agonist ciglitazone failed to up-regulate COX-2, indicating that the PGJ2 effect on COX-2 is PPARgamma independent. Furthermore, PGJ2 stabilized IkappaBalpha levels, indicating that NFkappaB is not active under these conditions. The blocking of neuronal NFkappaB activity by PGJ2 may be an important contributor to its neurotoxicity, insofar as NFkappaB transactivation seems to be required for neuronal survival in the CNS. Interleukin-1 (IL1) is a proinflammatory cytokine known to stimulate the expression of genes associated with inflammation, including COX-2. Notably, IL1 mRNA levels in the neuronal cells were increased by PGJ2 treatment. The proinflammatory cytokine may mediate COX-2 up-regulation by PGJ2 through p38MAPK and not JNK activation, in that only an inhibitor of the former prevented the COX-2 increase. Thiol-reducing agents, such as N-acetylcysteine, protected the neuronal cells from the deleterious effects of PGJ2, whereas ascorbic acid did not. Collectively, our findings suggest that proinflammatory conditions that lead to COX-2 up-regulation and the concomitant production of PGJ2 initiate a mechanism of self-destruction through an autotoxic loop between PGJ2 and COX-2 that may exacerbate neurodegeneration beyond a point of no return. Thiol-reducing antioxidants may offer an optimal strategy for halting this neurodegenerative process.