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In this study, Cetraria islandica polysaccharide (CIPs) was extracted by hot water extraction method and its effect on structural modification of immunomodulatory activities was investigated. This polysaccharide mainly consisted of carbohydrates (97.0%), Sulfate (1.2%) with one type of glucose. The average molecular weight (328.7 × 103 g/mol) was determined by size exclusion chromatography. The structure of the polysaccharide was found to be composed of (1→3) and (1→4)-β-D-glucopyranosyl units. The immunomodulatory activities of the crude polysaccharide and its derivatives, over-sulfated (OS1,2,3) and hydrolyzed (H1,2,3), were tested against NK-92 cells and RAW264.7 cells. The results obtained clearly demonstrated that over-sulfated (OS1,2,3)-treated NK-92 cells induced cytotoxicity in HeLa cells through the expressions of IFN-γ, NKp44, NKp30, and FasL. On the other hand, the hydrolyzed derivatives (H1,2,3) activated RAW264.7 cells through production of nitric oxide (NO) and mRNA expression of iNOS, IL-1, TNF-α, IL-6, IL-10 and IL-12 through the nuclear factor kappa-B (NF-κB) and mitogen activated protein kinases (MAPK) pathways. Our findings suggest that the presence of sulfate in the polysaccharide played a pivotal role in NK-92 cell however the Mw was a determinant factor in RAW264.7 cell activation, in which both cells were activated through the CR3 and TLR-4 signaling pathways.

The aqueous polysaccharide from Polygonatum sibiricum was extracted and fractionated using anion-exchange chromatography to obtain F1 fraction. The F1 was chemically sulfated and partially acid-hydrolyzed for the production of its over-sulfated (OS1,2,3) and hydrolyzed (HP1,2,3) derivatives, in which the sulfate content of OS1,2,3 was 7.5–17.1%, and the Mw of HP1,2,3 ranged from 18.2 × 103 to 57.3 × 103 g/mol. Considerable RAW264.7 cell activation was observed by HP1,2,3 with NO production of 34.9, 44.3 and 42.7 μM, respectively, as well as the mRNA expression of cytokines (IL-1β, IL-6, IL-10 and IL-12). NK cell cytotoxicity against HT-29 cell was facilitated by OS1,2,3 treatment with the increased gene expressions of INF-γ, Granzyme-B, perforin, NKG2D, and FasL. RAW264.7 cells appeared to be activated via MR and TLR4 mediated signaling pathway, but CR3 and TRL2 might play a main role in stimulating NK cells. Overall, the present study suggests the potential application of polysaccharides from P. sibiricum in functional foods and pharmacological industries.

The concentration of L-cysteine (Cys), a sulfur-containing amino acid, acts as an indicator and biomarker for various diseases in humans. Therefore, the identification and detection of abnormal concentrations of Cys are critically important for determining human health. In this study, excitation-dependent multiple emission nitrogen and sulfur co-doped carbon dots (NS-CDs) are synthesized using a one-pot hydrothermal method. The prepared NS-CDs exhibit a small particle size, good optical properties with high quantum yield, excellent stability, and excitation-dependent photoluminescence (PL) property. The synthesized NS-CDs display a narrow diameter ranging from 3 to 7 nm with a relatively higher quantum yield (QY) up to 11.4%. Under optimal conditions, these NS-CDs show good selectivity for Cys over other biologically relevant species and even other similar (di)thiols (GSH/DTT). The synthesized NS-CDs show excellent selectivity and sensitivity to Cys, with a low detection limit of 23 nM and a linear detection range from 0 to 10 μM. The NS-CDs and NS-CDs/Cys are used for cell imaging, showing low toxicity to HCT116 cells and exhibits green fluorescence when observed by confocal microscopy. Furthermore, the controllable and strong photoluminescent emission properties of the NS-CDs and NS-CDs/Cys are visualized as green photoluminescent ink under UV light illumination. The present study is an attractive and innovative perception into the biomedical applications of NS-CDs with controllable photoluminescence.

Uridine (UdN) is a pyrimidine nucleoside drug that is widely applied in the pharmaceutical industry. The solubility and biological activity of UdN have been enhanced by the formation of inclusion complexes with β-cyclodextrin derivatives (β-CDs), namely, hydroxypropyl-β-cyclodextrin (HPβ-CD) and sulfobutyl-ether-β-cyclodextrin (SBEβ-CD). Optical spectroscopy studies suggested the formation of 1:1 inclusion complexes between UdN and the β-CDs at 303 K, as determined from the Benesi–Hildebrand plot. The solid complexes of UdN and the β-CDs were prepared and characterized by various spectroscopic techniques, and the results indicated the inclusion of UdN in the β-CD cavity. The energetically favored binding interaction of UdN with the β-CDs was confirmed by molecular modeling studies. In addition, the investigations on the antibiofilm and antioxidant activities indicated that the β-CD/UdN complexes exhibited better fungicidal, cytotoxic, and cellular uptake activities than UdN.

Highly selective and rapid sensing of adenosine (AdN) based on novel photoluminescent vanadium nanoclusters (VNCs) anchored on molybdenum disulfide nanosheets (MoS2-NS) are reported for the first time. The remarkably photoluminescent VNCs features excellent water solubility, ultra-small size, and bright photoluminescence. The VNCs on the MoS2-NS (MoS2-NS/VNCs) are well dispersed in aqueous solution and features a remarkable increase in bandgap energy (2.67 eV) compared to MoS2-NS (2.10 eV). The photoluminescence of VNCs was quenched by MoS2-NS via photoluminescence resonance energy transfer (PRET) mechanism. Furthermore, MoS2-NS/VNCs exhibit high selectivity and sensitivity toward AdN over other AdN analogues, biomolecules, and metal ions. Consequently, the absorption spectral maxima appeared at 650 nm and emission significantly enhanced in intensity at 525 nm. Interestingly, the stronger binding of AdN with MoS2-NS/VNCs was fast with nearly 65.7 % photoluminescence restored in less than 5 min. The PL lifetime of MoS2-NS/VNCs (τ1 = 8.20 ns, τ2 = 0.68 ns) increased (τ1 = 10.48 ns, τ2 = 0.79 ns) in the presence of AdN. The observed limit of detection was 29 pM. This VNCs sensor system can be constructed as XNOR logic gate with MoS2 and AdN as chemical inputs by examining the mode of emission. Finally, this probe was used to detect AdN in live cells and human serum samples with satisfactory results.

The aim of the present study was to evaluate the effect of water-soluble polysaccharides from Cuminum cyminum to induce inflammatory response in immune cells and understand their underlying mechanisms. Weight average molecular weight (Mw) of polysaccharides varied between 191.4–512.2 × 103 g/mol. Polysaccharides induced RAW264.7 cells to release nitric oxide and express TNF-α, IL-1β, IL-6 and IL-12 inflammatory cytokines. Polysaccharides activated NK-92 cells to produce TNF-α, IFN-γ, perforin, granzyme B, NKG2D and FasL. Activations of RAW264.7 and NK-92 cells were through NF-κB and MAPKs signal pathways indicated by the presence of phosphorylated NF-κB, ERK, JNK and p38 proteins. The polysaccharide structure was mainly constituted of →4)-Galp-(1→, →3)-Galp-(1→, →2)-Arap-(1→ and →2)-Arap-(1→ glycosidic linkages. Overall results suggested that polysaccharides from C. cyminum possessing lower MW and greater expanded conformation more effectively stimulate RAW264.7 and NK-92 cells and thus could be considered for further studies on their biomedical applications.