Surface plasmon resonance (SPR) sensors based on a silver film suffer from signal degradation due to silver oxidation in aqueous sensing environments. To overcome this limitation, we fabricated the planar plasmonic substrate employing an atomic MoS2 layer on a silver surface. Successful production of a large-area MoS2 monolayer blocks the penetration of oxygen and water molecules. In addition, we theoretically and experimentally found that MoS2 layer on the silver film can improve the SPR sensitivity and stability significantly. In this study, the proposed SPR substrate has the potential to provide highly enhanced sensor platforms for surface-limited molecular detections.
We synthesized a fluorogenic disulfide-based naphthalimide thiol probe (ER-Naph) with a hydrophilic endoplasmic reticulum (ER)-guiding glibenclamide unit. Its ER targeting ability and high selectivity to GSH over thioredoxin, a potent competitor, were clearly demonstrated, both in solution and in vitro. Finally, a confocal microscopic investigation revealed that GSH levels in the ER were dramatically decreased under thapsigargin, brefeldin A, and tunicamycin-induced ER stress models.
20(S)-Protopanaxadiol 20-O-D-glucopyranoside, also called compound K (CK), exerts antidiabetic effects that are mediated by insulin secretion through adenosine triphosphate (ATP)-sensitive potassium (KATP) channels in pancreatic β-cells. However, the antidiabetic effects of CK may be limited because of its low bioavailability. In this study, we aimed to enhance the antidiabetic activity and lower the toxicity of CK by including it with β-cyclodextrin (CD) (CD-CK), and to determine whether the CD-CK compound enhanced pancreatic islet recovery, compared to CK alone, in an alloxan-induced diabetic zebrafish model. Furthermore, we confirmed the toxicity of CD-CK relative to CK alone by morphological changes, mitochondrial damage, and TdT-UTP nick end labeling (TUNEL) assays, and determined the ratio between the toxic and therapeutic dose for both compounds to verify the relative safety of CK and CD-CK. The CD-CK conjugate (EC50 = 2.158μM) enhanced the recovery of pancreatic islets, compared to CK alone (EC50 = 7.221μM), as assessed in alloxan-induced diabetic zebrafish larvae. In addition, CD-CK (LC50 = 20.68μM) was less toxic than CK alone (LC50 = 14.24μM). The therapeutic index of CK and CD-CK was 1.98 and 9.58, respectively. The CD-CK inclusion complex enhanced the recovery of damaged pancreatic islets in diabetic zebrafish. The CD-CK inclusion complex has potential as an effective antidiabetic efficacy with lower toxicity.