Atomic Force Microscope Guided SERS Spectra Observation for Au@Ag-4MBA@PVP Plasmonic Nanoparticles.

Recently polymer encapsulated surface-enhanced-Raman-scattering (SERS) probes with internal noble metal core-shell structure has found growing applications in biomedical applications. Here we studied the SERS spectra of Au@Ag-4MBA@PVP (4MBA: 4-mercaptobenzoic acid; PVP: polyvinylpyrrolidone) plasmonic nanoparticles produced from a chemical reduction method. By linking the atomic force microscope (AFM) with the homebuilt confocal Raman spectrometer thus to use AFM images as guidance, we realized the measurement of the SERS spectra from separated nanoparticles. We investigated the cases for single nanoparticles and for dimer structures and report several observed results including SERS spectra linearly scaled with laser power, abrupt boosting and abnormal shape changing of SERS spectra for dimer structures. Based on the finite element method simulation, we explained the observed ratio of SERS signals between the dimer structure and the single nanoparticle, and attributed the observed abnormal spectra to the photothermal effect of these plasmonic nanoparticles. Our study provides valuable guidance for choosing appropriate laser power when applying similar SERS probes to image biological cells.

A modified preauricular-temporal approach for fixing comminuted and redisplaced zygomatic arch fractures with the resorbable bone plate.

OBJECTIVE: To evaluate the effectiveness of the rigid internal fixation for comminuted and redisplaced zygomatic arch fractures by modified preauricular-temporal approach with the resorbable bone fixation. METHODS: Totally twenty patients aged from 14 to 68 years and admitted to our hospital between September 2006 and June 2011 were reviewed, of whom seventeen had a unilateral comminuted zygomatic arch fracture and three re-displaced arch fracture after failed closed reduction. The fracture segments were aligned to restore the preinjury form of the arch by rigid fixation with resorbable plates and screws through a modified preauricular-temporal incision. RESULTS: The fractures were well reduced, preauricular-temporal scar and lateral facial contour were aesthetically satisfying, and no case had limited mouth opening as well as facial palsy. The resorbable plates were not palpated one year after the operation. CONCLUSION: The rigid internal fixation through the preauricular-temporal approach with the resorbable bone is an effective method for the comminuted and redisplaced zygomatic arch fractures.

Structured light spots projected by a Dammann grating with high power efficiency and uniformity for optical sorting.

We report a method for microfluidic multiple trapping and continuous sorting of microparticles using an optical potential landscape projected by a Dammann grating, enabling a high power-efficient approach to forming a composite two-dimensional spots array with high uniformity. The Dammann grating is fabricated in a photoresist by optical lithography. It is employed to create an optical lattice for multiple optical trapping and sorting in a mixture of polymer particles (n = 1.59) and silica particles (n = 1.42) with the same diameters of 3.1 µm. In addition to the exponential selectivity by the projected optical landscapes, the proposed microfluidic sorting system has advantages in terms of high power efficiency and high uniformity due to the Dammann grating.

Encapsulation of photosensitizer into multilayer microcapsules by combination of spontaneous deposition and heat-induced shrinkage for photodynamic therapy.

Annealing of PDADMAC/PSS multilayer microcapsules assembled on PSS-doped CaCO(3) particles at 80 °C for 30 min reduces their size dramatically from 6.9 ± 0.3 to 3.1 ± 0.5 µm. Methylene blue molecules are encapsulated by spontaneous deposition and post-annealing with a concentration of 22 mg · mL(-1), which is 1000 times higher than the feeding value. The unreleased MB molecules are retained stably for a long time, which are then protected by the capsules against reductive enzymes and keep their photodynamic activity. The viability of HeLa cells incubated with the MB-loaded capsules decreases sharply from ≈ 75 (dark cytotoxicity) to ≈ 20% after irradiation with a laser at 671 nm and 60 J · cm(-2) for 75 s.

Preparation of polypyrrole-coated magnetic particles for micro solid-phase extraction of phthalates in water by gas chromatography-mass spectrometry analysis.

In this work, polypyrrole (PPy)-coated Fe(3)O(4) magnetic microsphere were successfully synthesized, and applied as a magnetic sorbent to extract and concentrate phthalates from water samples. The PPy-coated Fe(3)O(4) magnetic microspheres had the advantages of large surface area, convenient and fast separation ability. The PPy coating of magnetic microspheres contributed to preconcentration of phthalates from water sample, due to the π-π bonding between PPy coating and the analytes. Also, the coating could prevent aggregation of the microspheres, and improve their dispersibility. In this study, seven kinds of phthalates were selected as model analytes, including dimethyl phthalate (DMP), diethyl phthalate (DEP), di-iso-butyl phthalate (DIBP), di-n-butyl phthalate (DBP), benzylbutyl phthalate (BBP), di-(2-ethylhexyl) phthalate (DEHP) and di-n-octyl phthalate (DNOP), and gas chromatography-mass spectrometry (GC-MS) was introduced to detect the phthalates after sample pretreatment. Important parameters of the extraction procedure were investigated, and optimized including eluting solvent, the amount of Fe(3)O(4)@PPy particles, and extraction time. After optimization, the procedure took only 15 min to extract and concentrate analytes with high efficiency. Validation experiments showed that the optimized method had good linearity (0.985-0.998), precision (3.4-11.7%), high recovery (91.1-113.4%), and the limits of detection were from 0.006 to 0.068 µg/L. The results indicated that the novel method had advantages of convenience, good sensitivity, high efficiency, and it could also be applied successfully to analyze phthalates in real water sample.

[The clinical application of acellular dermal matrix to repair the defect of oral mucosa].

OBJECTIVE: To evaluate the clinical effect of acellular dermal matrix allograft in repairing the defect of oral mucosa. METHODS: Forty-two cases of large superficial defects in oral cavity were repaired by acellular dermal matrix. Defect areas included vestibule, tongue, the floor of mouth, buccal mucosa, palate, gingival and lip. Defect size was between 2.25 cm(2) and 12 cm(2). The basement membrane side of acellular dermal matrix was exposed to oral cavity, and another side was attached to the surgical wound surface. It was fixed by suture, reverse strapping and prepared template to overlaid large superficial defect of oral mucosa. The patients were followed up from 3 months to 1 year after operation. RESULTS: The wounds were completely healed in 40 cases, partially healed in 2 cases. There was no failure case. The healing was divided into two types: epithelialization healing pattern in 12 cases, attached healing pattern in 30 cases. Contraction of grafts occurred at 2 - 4 weeks. The contraction rate was 3.7% +/- 1.1% at fourth week. Scarring did not appear. CONCLUSION: The clinical result of acellular dermal matrix allograft in repair the defect of oral mucosa is good. Acellular dermal matrix can be taken as a substitute to autograft of skin.