Plasmon Coupling Enhanced Micro-Spectroscopy and Imaging for Sensitive Discrimination of Membrane Domains of a Single Cell.

Different cell membrane domains play different roles in many cell processes, and the discrimination of these domains is of considerable importance for the elucidation of cellular functions. However, the strategies available for distinguishing these cell membrane domains are limited. A novel technique called plasmon coupling enhanced micro-spectroscopy and imaging to discriminate basal and lateral membrane domains of a single cell combines the application of an additional plasmonic silver film for surface plasmon (SP) excitation to selectively excite and enhance the basal membranes in the near-field with directional enhanced microscopic imaging and spectroscopy. The SP and critical evanescent fields are induced upon excitation through a silver-coated semitransparent coverslip at the surface plasmon resonance and critical angles, respectively. The basal and lateral membrane domains located within the SP and critical evanescent fields can be selectively excited and distinguished by adjusting the incident angle of laser irradiation. Moreover, the brighter images and more intense spectra of membrane-targeting fluorescence-Raman probes under directional excitation than in conventional EPI mode allow clear identification of the membrane domains.

Intrinsic and acquired resistance to CDK4/6 inhibitors and potential overcoming strategies.

Abnormal activation of the cyclin-dependent kinases (CDKs), which result in aberrant cell proliferation, is one of the inherent characteristics of tumor. Thus targeting the activity of CDKs represents a promising tumor therapeutic strategy. Currently, the specific inhibitors that target CDK4 and CDK6 have been approved for the treatment of estrogen receptor positive, human epidermal growth factor receptor 2 negative (ER+ HER2-) breast cancer in combination with endocrine therapy; other combination strategies are being tested in a number of clinical trials. However, the acquired resistance to CDK4/6 inhibitors has emerged. As the cell cycle is orchestrated by a series of biological events, the alterations of other molecular events that regulate the cell cycle progression may be involved in intrinsic resistance to CDK4/6 inhibitors. In this review we mainly discuss the mechanisms underlying intrinsic resistance and acquired resistance to CDK4/6 inhibitors as well as combination strategies with other signal pathway inhibitors being tested in clinical and pre-clinical studies, to extend the use of CDK4/6 inhibitors in tumor treatment.

In situ and sensitive monitoring of configuration-switching involved dynamic adsorption by surface plasmon-coupled directional enhanced Raman scattering.

Surface adsorption studies play a crucial role in numerous fields from surface catalysis to molecular separation. However, investigation on adsorption mechanisms has been restricted to limited analytes and approaches, which calls for an in situ and sensitive surface analysis technique capable of revealing the mechanisms as well as discriminating different adsorbates and their geometry at different adsorption stages. In this study, we employed surface plasmon-coupled directional enhanced Raman scattering (SPCR), a novel technique developed by coupling surface plasmon-coupled emission with SERS, to study conformation-switching involved dynamic adsorption with background suppression and improved sensitivity (nearly 30-fold). We obtained the isotherms for a conformation-changing Raman model analyte, malachite green. An S-type Langmuir model was fitted from the time-resolved SPCR signals sensitively and without any interference from the bulk solution. The reorientation of the analyte from a predominantly parallel configuration to a perpendicular one was captured by the dramatic increase in the intensity ratios of the adsorption-related peaks to the adsorption-unrelated peak. We believe that this new sensitive and selective SPCR technique will be a promising tool for surface adsorption kinetics analysis.

Variable-Angle Nanoplasmonic Fluorescence Microscopy: An Axially Resolved Method for Tracking the Endocytic Pathway.

The study of endocytosis, which encompasses diverse mechanisms in biology, requires the utilization of high axial resolution to monitor molecular behavior on both the cell surface and interior of the cell. We have designed a novel axially resolved fluorescence microscopic technique, termed variable-angle nanoplasmonic fluorescence microscopy. The proof-of-principle of this approach is achieved by selectively following the events in the vicinity of a cell membrane or in a cell. We use a 30 nm Au-coated semitransparent coverslip as the nanoplasmonic chip to achieve both surface plasmon resonance excitation and critical angle excitation by tuning the incident angles. This approach leads to improved axial resolution compared to total internal reflection fluorescence microscopy, which is a common imaging technique in cell biology. It offers a unique opportunity to semiquantitatively determine fluorophore axial distributions in the cell. Observing the epidermal growth factor receptor-mediated endocytosis in Caski cells clearly demonstrates the potential application of this new method for cell biology studies.

[The SERS Detection of Sudan I by Using AAO as Template to Prepare the Substrate].

The large-scale controllable, ordered two-dimensional arrays of gold nanostructure with hot-spot were prepared together with chemical molecules were modified on the surface to concentrate Sudan I within the zone of the SERS effect, which lead to analytical detection of Sudan I in high resolution. The vapor of gold was deposed on anodic aluminum oxide(AAO) template by -200 nm thickness to replicate its nanochannels, and the negative structure i. e. large-scale ordered gold nano-hemisphere array, was obtained after the removal of the template of AAO by NaOH solution. Au nano-hemisphere array was modified by 1-Dodecanethiol which can be self-assembled monolayer on the surface and concentrate Sudan I within the zone of the SERS detection, which can facilitate the measurement of Sudan I. Due to the order and regularity of Au nano-hemisphere array, the signal of Sudan I in the range of laser illumination is stable and uniform, and the quantitative analysis of Sudan I was realized. The SERS intensity of Sudan I is logistic proportional to the concentration in the range of 10(-7) to 5 x 10(-4) mol x L(-1). The corresponding correlation coefficient of the liner equation is 0.99, the recoveries of Sudan I are between 77% - 117%. The limit of detection for Sudan I is 4 x 10(-1) mol x L(-1), comparable to that of HPLC of Chinese national standard method.

[Self-assembled film of gold nanoparticles at a air/water interface used as a SERS substrate to detect melamine].

Self-assembled monolayer film of gold nanoparticles (55 nm) was formed at air-water interface by the driving force of wettability-shift of gold nanoparticles from hydrophilic property to hydrophobic property when encapsulated with 1-dodecanethiol. SEM image shows that the structure of the surface is nearly monolayer with closed arrays of uniform particle size when the film is transferred onto Si wafer. The substrate can be used for SERS substrate to realize semiquantitative analysis of melamine and the detection limit can reach l x 10(-9) g x L(-1). This SERS substrate is of wide application, not only for melamine but also for nonpolar molecule such as polycyclic aromatic hydrocarbons.

Smart pH-Modulated Two-Way Photoswitch Based on a Polymer-Modified Single Nanochannel.

In this article, we have demonstrated a smart pH-modulated two-way photoswitch that can reversibly switch ion transport under alternating light exposure over a wide pH range. This photoswitch was prepared by functionalizing the interior of a single conical glass nanochannel with a poly-spiropyran-linked methacrylate (P-SPMA) polymer through surface-initiated atom transfer radical polymerization. The P-SPMA polymer brushes comprise functional groups that are responsive to light and pH, which can cause configuration and charge changes to affect the properties of the nanochannel wall. The SPMA polymer-modified nanochannel not only reversibly controlled ion transport under alternating light irradiation but also efficiently and flexibly regulated the direction and extent of the ion transport based on the pH. This two-way photoswitch exhibits the considerable potential of photoresponsive polymers for the advancement of "intelligent" bionic nanochannel devices for ion screening and optical sensing in various applications.

Excitation-Emission Synchronization-Mediated Directional Fluorescence: Insight into Plasmon-Coupled Emission at Vibrational Resolution.

Light-matter interactions have always been a fundamentally significant topic that has attracted much attention. It is important to reveal a fluorophore-plasmon interaction on the nanoscale. However, as a powerful investigative tool, fluorescence spectroscopy still suffers from a limited spectral resolution and the susceptibility to interfering substances. In this work, excitation-emission synchronization-mediated surface-plasmon-coupled emission (EES-SPCE) is proposed to break the bottleneck. By actively screening the energy transitions for observation, an improved spectral resolution has been achieved, which is advantageous to the investigation of the fluorophore-plasmon interactions under different coupling modes. The spectral information related to the plasmonic interactions through tuning vibrational energy levels is clearly distinguished at directional emission angles. EES-SPCE is demonstrated to selectively and efficiently extract the coupled emission from the vibrational resolution, which would open up the opportunity to improve the capability of spectral feature identification and signal collection for practical applications of plasmonic fluorescence spectroscopy.

Surface Plasmon Coupled Fluorescence-Enhanced Interfacial "Molecular Beacon" To Probe Biorecognition Switching: An Efficient, Versatile, and Facile Signaling Biochip.

Integrating probes and a substrate together, a fluorescence-enhanced interfacial "molecular beacon" (FEIMB) is demonstrated, based on directional surface plasmon coupled emission. Through this simple yet efficient interfacial modulation engineering to create an interfacial quencher (graphene oxide)-enhancer (gold nanofilm) pair, the quenching-to-enhancing region of FEIMB can be actively tuned. Therefore, it provides a spatial match between signal transduction and interface-mediated biorecognition switching. Via combination of strong quenching and efficient plasmonic coupling, a synergistically amplified signal-to-background ratio of >1000-fold has been achieved. FEIMBs have been employed in protein and DNA detection, creating a high-performance and universal chip-based plasmon-mediated fluorescence sensing platform.

In Situ Monitoring of Fluorescent Polymer Brushes by Angle-Scanning Based Surface Plasmon Coupled Emission.

Fluorescent polymers have attracted interest in many fields such as sensing, diagnostics, imaging, and organic electronic devices. Real-time techniques to monitor and understand the polymerization process are important for obtaining controllable fluorescence polymers. We present a new technique to in situ monitor the growth process of fluorescent polymer brushes by using angle-scanning based surface plasmon coupled emission (AS-SPCE) approach during electrochemically mediated atom-transfer radical polymerization. The polymer thickness was determined by modeling the location of SPCE emission angle(s) with theoretical calculation. The advantages of unique angle distribution patterns, thickness dependence and effective background rejection of AS-SPCE guarantee the success in the real-time investigation for controllable fabrication of fluorescent polymers.

The synergistic enhancement of silver nanocubes and graphene oxide on surface plasmon-coupled emission.

The enhancement of surface plasmon-coupled emission (SPCE) by the synergistic effect of silver nanocubes (AgNCs) and graphene oxide (GO) on gold film has been observed with the enhancement factor over 30. The enhancement mechanisms were investigated through simulating the electromagnetic (EM) field patterns of near field and testing different concentration of AgNCs and thickness of dye layer. The enhancement was mainly triggered by the high electromagnetic field of AgNCs, the interaction between localized surface plasmons (LSP) and propagating surface plasmons (PSP) and the assistance of GO. This synergistic enhancement strategy provides a simple way to increase SPCE signal and enable develop a new fluorescence-based detection system.

[Adsorption of Pb2+ and Cd2+ from Aqueous Solution Using Vermicompost Derived from Cow Manure and Its Biochar].

Using vermicompost (CV) as raw material, its biochar (CVC350) was prepared at 350℃ and then their physio-biochemical properties were characterized. Furthermore, adsorption studies were performed in a batch system for removing Pb2+ and Cd2+ ions from solution. The characterization results revealed much higher surface area, smaller pore size, greater aromaticity and nonpolarity of CVC350 as compared to CV. Batch adsorption experiments revealed that both the adsorption of Pb2+ and Cd2+ onto CV or CVC350 fitted Langmuir isotherm model very well, and the maximum adsorption capacity of Pb2+ was in the order of CVC350>CV, but no difference was observed for the adsorption capacity of Cd2+ between CV and CVC350. The desorption studies showed that both CV and CVC350 had much higher adsorption rate for Pb2+ than that for Cd2+, and the Cd2+ adsorbed could be more easily desorbed from CV and CVC350 compared with that for the Pb2+ adsorbed. Both the dynamic adsorption process of Pb2+ onto CV and CVC350 was a rapid process, however, the adsorption process of Cd2+ onto CV and CVC350 could be separated into the first rapid step and the second slower step. The adsorption capacity of Pb2+ or Cd2+ onto CV and CVC350 was only affected by the much lower initial pH of the solution, besides, the adsorption capacity of Cd2+ onto CV and CVC350 was relatively more influenced by the initial pH compared with that of Pb2+. Moreover, FTIR analysis showed that the adsorption of Pb2+ and Cd2+on CV depended on the active sites such as aliphatic alcohol, aliphatic acid,carbonates as well as phosphate while that on CVC350 mainly relied on aromatic alcohol, aromatic acid and carbonates.

[Application of bridge wire splint fixation on ankle dorsiflexion in femoral shaft fractures in young children].

OBJECTIVE: To explore the technique and therapeutic effect of bridge wire splint fixation with ankle dorsiflexion for the treatment of femoral shaft fractures in young children. Methods:From June 2006 to June 2012,45 young children with femoral shaft fractures were treated by bridge wire splint fixation with ankle dorsiflexion,which was designed according to arch bridge mechanical principle and structure. There were 31 males and 14 females with an average age of 3.2 years old ranging from 8 months to 5.5 years old; 14 cases were upper 1/3 femoral fractures,26 cases were middle 1/3 femoral fractures,5 cases were lower 1/3 femoral fractures; 20 cases were transverse fractures, 14 cases were oblique fractures,6 cases were spiral frac- tures, and 5 cases were comminuted fractures. X-ray, follow-up imaging changes,clinical curative effect and complications were assessed. RESULTS: Forty-five patients were followed up for 6 to 21 months (averaged 12 months). All fractures were reached clinical bone healing after 5 to 7 weeks (averaged 6 weeks) fixation. Seven cases appearred limb soft tissue complications, including buttocks bedsore,dorsal foot and Achilles tendon epidermal necrosis, and healed after dressing and removal of external fixation. During follow-up,the original overlap angle and lateral displacement were remodeled, and limbs were restored to the normal line of force and bone structure. According to Flynn standard, 35 cases got excellent results, 8 cases good, 2 cases fair. CONCLUSION: The bridge wire splint fixation with ankle dorsiflexion for the treatment of femoral. shaft fractures in young children (less than 6 years old) is safe,feasible, simple,and has raliable effect, which can be applied in primary hospitals.

[Concentrations and distribution of organochlorine pesticides in the surface sediments of Jiaozhou Bay, Taozi Bay and Sishili Bay].

Forty-eight surface sediment samples collected from Jiaozhou Bay, Taozi Bay and Sishili Bay were analyzed for organochlorine pesticides (OCPs) by Gas Chromatography. Results showed that average concentrations of HCHs, HCB and DDTs in marine sediments were 0.33, 0.31 and 10.33 ng x g(-1) in Jiaozhou Bay and 0.26, 0.10 and 4.56 ng x g(-1) in Taozi Bay and Sishili Bay, respectively. Contamination status of OCPs was relatively higher in Jiaozhou Bay than in other inland coastal regions, especially for the levels of DDTs; however, OCPs concentrations were relatively low in Taozi Bay and Sishili Bay. The source of HCHs could be mainly attributed to the heavy historical application in agricultural areas and late transport to coastal region through surface runoff or riverine discharge, and DDTs were primarily originated from the use of technical DDTs. Fresh input of lindane and dicofol-type DDTs were found in several sites, such as Qingdao Port. High concentrations of DDTs in Jiaozhou Bay should arouse much attention.

[Comparison of efficacy between bridge wire splints and Bryant traction for the treatment of femoral shaft fractures in children].

OBJECTIVE: To compare clinical effects between bridge wire splint fixation and traditional Bryant traction for the treatment of femoral shaft fractures in children. METHODS: From June 2006 to June 2009,38 children with femoral shaft fractures were treated with bridge wire splint fixation and Bryant traction. In bridge wire splint group, there were 15 males and 6 females, ranging in age from 8 months to 5.3 years, with an average of (2.3 +/- 0.6) years. According to fracture site classification, 5 patients were upper 1/3 femoral fractures, 9 patients were middle 1/3 femoral fractures,and 7 patients were lower 1/3 femoral fractures. In Bryant traction group,there were 10 males and 7 females, ranging in age from 10 months to 3.2 years, with an average of (2.2 +/- 0.4) years. According to fracture site classification, 4 cases were upper 1/3 femoral fractures, 10 patients were middle 1/3 femoral fractures, 3 patients were lower 1/3 femoral fractures. The clinical features, X-ray healing time,weight-bearing time and complications of the two groups were compared. RESULTS: Comparison of fracture healing time: bridge wire splint group was (6.0 +/- 0.3) weeks and Bryant traction group was (6.2 +/- 0.4) weeks; the time of weight-bearing in bridge wire splint group was (6.1 +/- 1.0) weeks and in Bryant traction group was (6.4 +/- 1.2) weeks; there was no significant difference between two groups. There was a significant difference in soft tissue complication between bridge wire splint group occurred in 3 cases and 13 cases in Bryant traction group. According to the criteria of clinical efficacy,in Bryant traction group, 12 patients got an excellent result, 4 good and 1 fair; in bridge wire splint group, the data were 17, 3 and 1 respectively,and there was no significant difference between the two groups. CONCLUSION: Both of bridge wire splint fixation and traditional Bryant traction for the treatment of femoral shaft fractures in children have good efficacy. Compared with Bryant traction,bridge wire splint fixation is simple, safe and has reliable effect.