Large-scale fabrication of nanodimple arrays for surface-enhanced Raman scattering.

Here we report a simple bottom-up technology for scalably fabricating gold nanodimple arrays with tunable nanostructures for surface-enhanced Raman scattering (SERS). Double-layer silica colloidal crystal-polymer nanocomposites with an unusual non-close-packed structure created using a spin-coating technique are utilized as structural templates. A variety of nanodimple structures, including simple monolayer voids, nanoring-like nanodimples, and binary-void nanodimples, can be reproducibly templated over wafer-sized areas by simply controlling the conditions during an oxygen plasma etching process. Normal-incidence specular reflection measurements show that the resulting gold nanodimple arrays exhibit tunable surface plasmon properties. The efficient electromagnetic coupling between neighboring nanodimples and inner-outer walls of nanoring-like nanodimples leads to high SERS enhancement factors (>10(8)). Numerical simulations based on a finite-difference time-domain model complement the experimental measurements, showing the spatial distribution of electromagnetic "hot spots" surrounding the periodic gold nanodimple arrays.

High surface plasmon resonance sensitivity enabled by optical disks.

We report a systematic, experimental, and theoretical investigation on the surface plasmon resonance (SPR) sensing using optical disks with different track pitches, including Blu-ray disk (BD), digital versatile disk (DVD), and compact disk (CD). Optical reflection measurements indicate that CD and DVD exhibit much higher SPR sensitivity than BD. Both experiments and finite-difference time-domain simulations reveal that the SPR sensitivity is significantly affected by the diffraction order of the SPR peaks and higher diffraction order results in lower sensitivity. Numerical simulations also show that very high sensitivity (∼1600 nm per refractive index unit) is achievable by CDs.

Effectiveness of platelet-rich plasma injection in patients with temporomandibular joint osteoarthritis: a systematic review and meta-analysis of randomized controlled trials.

OBJECTIVE: The aim of this study was to investigate the effectiveness of platelet-rich plasma (PRP) injection after arthrocentesis or arthroscopy in patients with temporomandibular joint osteoarthritis. STUDY DESIGN: Electronic databases (PubMed, EMBASE, Scopus, and Cochrane Library) were searched for reports up to July 30, 2018. We included all published or unpublished randomized controlled trials (RCTs). The primary outcome was pain reduction, and the secondary outcome was the improvement of maximal mouth opening. Weighted mean differences were utilized for random-effect meta-analysis. RESULTS: Five RCTs were enrolled in the meta-analysis, comparing PRP injection to placebo (hyaluronic acid [HA] injection, saline injection, or no injection). The results revealed that PRP injection was more effective than placebo in pain reduction, but no in the improvement of maximal mouth opening, in the long term. In the subgroup analysis, PRP injection yielded better outcome only in pain reduction comparing to HA injection (Weighted mean difference 1.34, 95% confidence interval [CI] 0.95-1.73). CONCLUSIONS: This meta-analysis demonstrated that PRP injection provided adjuvant efficacy to arthrocentesis or arthroscopy in pain reduction for temporomandibular joint osteoarthritis in the long term. Furthermore, PRP injection significantly reduced pain better compared with HA injection, saline injection, or no injection.

Connective tissue growth factor differentially binds to members of the cystine knot superfamily and potentiates platelet-derived growth factor-B signaling in rabbit corneal fibroblast cells.

AIM: To study the binding of connective tissue growth factor (CTGF) to cystine knot-containing ligands and how this impacts platelet-derived growth factor (PDGF)-B signaling. METHODS: The binding strengths of CTGF to cystine knot-containing growth factors including vascular endothelial growth factor (VEGF)-A, PDGF-B, bone morphogenetic protein (BMP)-4, and transforming growth factor (TGF)-ß1 were compared using the LexA-based yeast two-hybrid system. EYG48 reporter strain that carried a wild-type LEU2 gene under the control of LexA operators and a lacZ reporter plasmid (p80p-lacZ) containing eight high affinity LexA binding sites were used in the yeast two-hybrid analysis. Interactions between CTGF and the tested growth factors were evaluated based on growth of transformed yeast cells on selective media and colorimetric detection in a liquid ß-galactosidase activity assay. Dissociation constants of CTGF to VEGF-A isoform 165 or PDGF-BB homo-dimer were measured in surface plasma resonance (SPR) analysis. CTGF regulation in PDGF-B presentation to the PDGF receptor ß (PDGFRß) was also quantitatively assessed by the SPR analysis. Combinational effects of CTGF protein and PDGF-BB on activation of PDGFRß and downstream signaling molecules ERK1/2 and AKT were assessed in rabbit corneal fibroblast cells by Western analysis. RESULTS: In the LexA-based yeast two-hybrid system, cystine knot motifs of tested growth factors were fused to the activation domain of the transcriptional factor GAL4 while CTGF was fused to the DNA binding domain of the bacterial repressor protein LexA. Yeast co-transformants containing corresponding fusion proteins for CTGF and all four tested cystine knot motifs survived on selective medium containing galactose and raffinose but lacking histidine, tryptophan, and uracil. In liquid ß-galactosidase assays, CTGF expressing cells that were co-transformed with the cystine knot of VEGF-A had the highest activity, at 29.88 ± 0.91 fold above controls (P < 0.01). Cells containing the cystine knot of BMP-4 expressed the second most activity, with a 24.77 ± 0.47 fold increase (P < 0.01). Cells that contained the cystine knot of TGF-ß1 had a 3.80 ± 0.66 fold increase (P < 0.05) and the ones with the cystine knot of PDGF-B had a 2.64 ± 0.33 fold increase of ß-galactosidase activity (P < 0.01). Further SPR analysis showed that the association rate between VEGF-A 165 and CTGF was faster than PDGF-BB and CTGF. The calculated dissociation constant (KD) of CTGF to VEGF165 and PDGF-BB was 1.8 and 43 nmol/L respectively. PDGF-BB ligand and PDGFRß receptor formed a stable complex with a low dissociation constant 1.4 nmol/L. Increasing the concentration of CTGF up to 263.2 nmol/L significantly the ligand/receptor binding. In addition, CTGF potentiated phosphorylation of PDGFRß and AKT in rabbit corneal fibroblast cells stimulated by PDGF-BB in tissue culture condition. In contrast, CTGF did not affect PDGF-B induced phosphorylation of ERK1/2. CONCLUSION: CTGF has a differential binding affinity to VEGF-A, PDGF-B, BMP-4, and TGF-ß. Its weak association with PDGF-B may represent a novel mechanism to enhance PDGF-B signaling.

Nanopyramid surface plasmon resonance sensors.

We report the achievement of sensitive chemical and biological sensing using periodic gold nanopyramids with nanoscale sharp tips created by a simple and scalable colloidal templating approach. The sharp tips and the long-range periodic structure of the nanopyramid arrays enable the excitement of both localized and propagating surface plasmons. The optical reflection and the detection sensitivity of the templated nanopyramid surface plasmon resonance sensors agree reasonably well with the theoretical predictions using a finite-difference time-domain model. We have also demonstrated that specific antigen-antibody binding can be detected by using nanopyramid arrays in a real-time and label-free manner.