Monitoring the penetration and accumulation of gold nanoparticles in rat skin ex vivo using surface-enhanced Raman scattering spectroscopy

Contamination by accidental cutaneous contact with the commercial products and the air pol-hutants raised a considerable health and safety issue.This study aimed to trace the dynamics of the 20 nm gold nanopartide(GNP)penetration and accumulation in rat skin tissues using a surface-enhanced Raman scattering(SERS)techmique.After the topical application of GNPs on rat skin surface,the SERS spectra were recorded for every 15 pum to an overall depth of 75 pum from skin surface for 150 min.The processes of GNP penetration in rat skin were accompanied by aggregation of GNPs,which affected SERS spectra.The results revealed that 20 nm GNPs can penetrate through stratum corneum layer,viable epidermis layer,and then into dermis layer.This study demonstrated for the first time the potential of SERS spectroscopy to monitor the penetration and accumulation of GNPs in rat skin.

Effect of Low Energy Electron Exposure on Ion Scattering Spectroscopy

The effect of low energy electron (LEE) exposure on ISS, including on the sputter peak and scatter peak as well as on ion neutralization, has been investigated for different samples. Some new results are discussed.

Characterization of gold nanoparticle bioconjugation by resonance light scattering correlation spectroscopy

Gold nanoparticles （GNPs） have been widely used as probes and nanomaterials in certain biological and biomedical fields thanks to its special physical and chemical properties. However, it is still difficult to characterize GNPs-bioconjugates in solution, which has greatly limited further bioapplications of GNPs. In this study, we reported a single particle method for characterizing GNPs- biomolecules in solution using resonance light scattering correlation spectroscopy （RLSCS）. The interaction of GNPs with bovine serum albumin （BSA） and thiol-modified oligonucletides were investigated.

Advancing Energy Systems with In-Situ and Operando Surface-Enhanced Raman Scattering Spectroscopy

Surface-enhanced Raman scattering spectroscopy(SERS)has emerged as a powerful analytical technique to enable nanoscale investigations of energy systems.This mini-review focuses on the applications of in-situ and operando SERS in energy-related research,highlighting its unique capabilities and significant contributions to understanding energy storage and conversion processes.We first introduce the fundamental principles of SERS,key SERS-derived techniques,and commonly employed platforms.Subsequently,we delve into the diverse applications of in-situ and operando SERS across various energy systems,encompassing photocatalytic and electrocatalytic systems,fuel cells,solar cells,and batteries.Finally,we conclude with our perspective on the current challenges and prospects in this area.We hope thismini-review serves as an essential overview to guide the design and implementation of in-situ and operando SERS studies of energy systems.

Optical spectroscopy study of damage evolution in 6H-SiC by H_(2)^(+)implantation

Lattice defects induced by ion implantation into SiC have been widely investigated in the decades by various techniques.One of the non-destructive techniques suitable to study the lattice defects in SiC is the optical characterization.In this work,confocal Raman scattering spectroscopy and photoluminescence spectrum have been used to study the effects of 134-keV H_(2)^(+)implantation and thermal treatment in the microstructure of 6H-SiC single crystal.The radiation-induced changes in the microstructure were assessed by integrating Raman-scattering peaks intensity and considering the asymmetry of Raman-scattering peaks.The integrated intensities of Raman scattering spectroscopy and photoluminescence spectrum decrease with increasing the fluence.The recovery of the optical intensities depends on the combination of the implantation temperature and the annealing temperature with the thermal treatment from 700℃to 1100℃.The different characterizations of Raman scattering spectroscopy and photoluminescence spectrum are compared and discussed in this study.

Characterization of the Diamond-like Carbon Based Functionally Gradient Film

Diamond-like carbon coatings have been used as solid lubricating coatings in vacuum technology for their good physical and chemical properties. In this paper, the hybrid technique of unbalanced magnetron sputtering and plasma immersion ion implantation (Plll) was adopted to fabricate diamond-like carbon-based functionally gradient film, N/TiN/Ti(N,C)/DLC, on the 304 stainless steel substrate. The film was characterized by using Raman spectroscopy and glancing X-ray diffraction (GXRD), and the topography and surface roughness of the film was observed using AFM. The mechanical properties of the film were evaluated by nano-indentation. The results showed that the surface roughness of the film was approximately 0.732 nm. The hardness and elastic modulus, fracture toughness and interfacial fracture toughness of N/TiN/Ti(N,C)/DLC functionally gradient film were about 19.84 GPa, 190.03 GPa, 3.75 MRa.m1/2 and 5.68 MPa.m1/2, respectively. Compared with that of DLC monolayer and C/TiC/DLC multilayer, this DLC gradient film has better qualities as a solid lubricating coating.

Microwave Synthesis of Au Nanoparticles with the System of AuCl_4-CH_3CH_2OH

The Au nanoparticles has been prepared by microwave high-pressure procedure with alcohol as the reducing agent. The color of colloidal Au nanoparticles is blue-violet. The maximum absorption spectrum of colloidal Au is at 580 nm, and the resonance scattering peak is at 580 nm. Using this method, the colloidal Au of long-time stability can be prepared Simply and quickly.

Structural evolution and bandgap modulation of layeredβ-GeSe_(2)single crystal under high pressure

Germanium diselenide(GeSe_(2))is a promising candidate for electronic devices because of its unique crystal structure and optoelectronic properties.However,the evolution of lattice and electronic structure ofβ-GeSe_(2)at high pressure is still uncertain.Here we prepared high-qualityβ-GeSe_(2)single crystals by chemical vapor transfer(CVT)technique and performed systematic experimental studies on the evolution of lattice structure and bandgap ofβ-GeSe_(2)under pressure.High-precision high-pressure ultra low frequency(ULF)Raman scattering and synchrotron angle-dispersive x-ray diffraction(ADXRD)measurements support that no structural phase transition exists under high pressure up to 13.80 GPa,but the structure ofβ-GeSe_(2)turns into a disordered state near 6.91 GPa and gradually becomes amorphous forming an irreversibly amorphous crystal at 13.80 GPa.Two Raman modes keep softening abnormally upon pressure.The bandgap ofβ-GeSe_(2)reduced linearly from 2.59 eV to 1.65 eV under pressure with a detectable narrowing of 36.5%,and the sample under pressure performs the piezochromism phenomenon.The bandgap after decompression is smaller than that in the atmospheric pressure environment,which is caused by incomplete recrystallization.These results enrich the insight into the structural and optical properties ofβ-GeSe_(2)and demonstrate the potential of pressure in modulating the material properties of two-dimensional(2D)Ge-based binary material.

REAL-TIME ASSESSMENT OF MICROWAVE ABLATION EFFICACY BY NIR SPECTROSCOPIC TECHNIQUE

Microwave ablation(MWA)status monitoring in real time plays a key role in assessment of therapeutic fectiveness.As a novel realtime assessment method,near infrared spectroscopy(NIRs)was used to evaluate the ablation eficacy.MWA experiments were carried out on in vitroporcine livers.An optical measurement system for biological tissue is developed by our lab tomonitor reduced scattering coefficient(μ')at 690 nm of the coagulation zones.It is noted that p's of liver tissue,which increases as the liver tissue being ablated,is clearly related with the co-agulation status.μ's of normal tissue and coagulated tissue is 3-5 and 17-19 cm-1,respectively.Continuous changes ofμ's demonstrate that optical parameter can be used as an efficacy evaluation factor because it essentially indicates the degree of thermal damage.Compared withtemperat ure,optical parameter is more sensitive and accurate,which is promising for real-timetherapeutic eficacy assessment in MWA.

Multispectral light scattering endoscopic imaging of esophageal precancer

Esophageal adenocarcinoma is the most rapidly growing cancer in America.Although the prognosis after diagnosis is unfavorable,the chance of a successful outcome increases tremendously if detected early while the lesion is still dysplastic.Unfortunately,the present standard-of-care,endoscopic surveillance,has major limitations,since dysplasia is invisible,often focal,and systematic biopsies typically sample less than one percent of the esophageal lining and therefore easily miss malignancies.To solve this problem we developed a multispectral light scattering endoscopic imaging system.It surveys the entire esophageal lining and accurately detects subcellular dysplastic changes.The system combines light scattering spectroscopy,which detects and identifies invisible dysplastic sites by analyzing light scattered from epithelial cells,with rapid scanning of the entire esophageal lining using a collimated broadband light beam delivered by an endoscopically compatible fiber optic probe.Here we report the results of the first comprehensive multispectral imaging study,conducted as part of routine endoscopic procedures performed on patients with suspected dysplasia.In a double-blind study that characterized the system’s ability to serve as a screening tool,55 out of 57 patients were diagnosed correctly.In addition,a smaller double-blind comparison of the multispectral data in 24 patients with subsequent pathology at locations where 411 biopsies were collected yielded an accuracy of 90%in detecting individual locations of dysplasia,demonstrating the capability of this method to serve as a guide for biopsy.

Resonance Scattering Spectral Determination of HSA with a New Scattering Enhanced Reagent of K_3[Fe(CN)_6]

A new resonance scattering spectral (RSS) method for the determination of human serum album (HSA) has been proposed with the resonance scattering enhanced reagent of K 3[Fe-(CN) 6]. In the medium of HCl (2.0×10 -3 mol/L), HSA may combine with 3- by intermolecular forces (mainly by electrostatic force) to form { 3- n-HSA m+} k nanoparticle of the ion-association complexes of HSA m+- 3- n. There is a strongest resonance scattering intensity at 351 nm, owing to the existence of the resonance scattering of the nanoparticle, 3- molecular absorption and the non-distribution of the emission intensity of Xe lamp in the range of 200-1000 nm. In addition, two resonance scattering peaks at 470 and 700 nm were observed. The HSA concentration in the range of 0-12 μg/mL is linear to the resonance scattering intensity at 351 nm. The determination limit of this method is 0.1 μg/mL HSA, about ten-fold lower than that of Coomassie brilliant blue protein assay. This method has been used for the determination of HSA in human serum and synthetic samples with satisfactory results. The mechanism of enhanced resonance scattering light, the TEM of the particle, the concepts of quasi-elastic absorption and un-elastic absorption were also discussed.

Macroscopic Ag nanostructure array patterns with high-density hotspots for reliable and ultra-sensitive SERS substrates

Syn thesis of metal nano structures arrays with large amounts of small nano-gaps on a homoge nous macroscale is of significant in terest and importa nee in chemistry,biotech no logy,physics,and nan otech no logy because of their enhan ced properties.However,the fabricatio n of uncovered nano-gaps with high-density and uniformity is rather difficult due to the complex and multiple synthetic steps.In this research,a facile and low-cost approach is demonstraind for the synthesis of high-density small nano-gaps(about 3.4 nm)between silver nanostructure array patter ns(SNAPs)over a large area.Uniform nan o?hole patter ns were periodically gen erated over an entire substrate using nano-impri nt lithography.Electrochemical reacti on at the high over-potential produced multiple silver nano crystals inside the nano-hole patter ns,gen erati ng a high-de nsity of small and un covered nano-gaps.Finally,we fully dem on strate their applicati on in the rapid detectio n of rhodamine 6G(R6G)molecules by surface-enhaneed Raman scattering(SERS)spectroscopy with a very low detection limit(1 fM)as well as excellent signal uniformity(RSD<8.0%±2.5%),i ndicati ng an extra ordinary capability for single-molecule detecti on.