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Silicon‐Based Laser Desorption Ionization Mass Spectrometry for the Analysis of Biomolecules: A Progress Report
摘要： Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is widely used in the biomedical field for the label-free analysis of molecules such as drugs, lipids, peptides, proteins, and biological tissues for molecular imaging. However, organic matrices used in traditional MALDI-MS applications introduce excessive interferences in the low m/z range. For this reason, nanostructured materials—and in particular silicon-based LDI strategies—have become a promising alternative, since they provide a much weaker background. Herein, the recent developments in fabrication, functionalization, and practical applications of silicon-based LDI-MS methods are reviewed. Also the basic requirements of silicon-based substrates for optimal LDI analysis by providing an overview of the LDI mechanisms that use silicon-based substrates instead of organic matrices are reported. Finally, the considerable potential of silicon-based substrates is discussed, giving suggestions for topics for future research.
关键词： silicon nanostructures,laser desorption ionization (LDI),surface functionalization,mass spectrometry imaging (MSI)
更新于2025-09-19 17:13:59
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Ultra-fast laser micro processing by multiple laser spots
摘要： In the direct processing of three dimensional micro structures for surface functionalization, usp-lasers provide the necessary resolution and quality. The increasing resolution brings along a rising machining time which leads to the unavoidable demand of multiple spots. In this paper a newly developed high compact ps-laser with repetition rates of up to 8 MHz and an average power of 500 W was distributed by a diffractive element on a 16 channel acousto optical modulator that individually modulates each of the 16 spots. The typical laser based micro processing method was enhanced to reach a machining technology in which 16 different layers could be processed within one path. In a further step, 4 of these high compact beam deliveries could be integrated in one cylinder micro processing system to generate at least 64 individual acting laser spots. Different functional structures were processed and shown in this paper.
关键词： surface functionalization,Three dimensional micro strucutures,Mulit-Spot,Diffractive Optical Element DOE,usp-laser
更新于2025-09-16 10:30:52
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Covalent Surface Modification Effects on Singlea??Walled Carbon Nanotubes for Targeted Sensing and Optical Imaging
摘要： Optical nanoscale technologies often implement covalent or noncovalent strategies for the modification of nanoparticles, whereby both functionalizations are leveraged for multimodal applications but can affect the intrinsic fluorescence of nanoparticles. Specifically, single-walled carbon nanotubes (SWCNTs) can enable real-time imaging and cellular delivery; however, the introduction of covalent SWCNT sidewall functionalizations often attenuates SWCNT fluorescence. Recent advances in SWCNT covalent functionalization chemistries preserve the SWCNT’s pristine graphitic lattice and intrinsic fluorescence, and here, such covalently functionalized SWCNTs maintain intrinsic fluorescence-based molecular recognition of neurotransmitter and protein analytes. The covalently modified SWCNT nanosensor preserves its fluorescence response towards its analyte for certain nanosensors, presumably dependent on the intermolecular interactions between SWCNTs or the steric hindrance introduced by the covalent functionalization that hinders noncovalent interactions with the SWCNT surface. These SWCNT nanosensors are further functionalized via their covalent handles with a targeting ligand, biotin, to self-assemble on passivated microscopy slides, and these dual-functionalized SWCNT materials are explored for future use in multiplexed sensing and imaging applications.
关键词： single-walled carbon nanotubes,biosensing,fluorescence,imaging,surface functionalization
更新于2025-09-16 10:30:52
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Hydrophilic to ultrahydrophobic transition of Al 7075 by affordable ns fiber laser and vacuum processing
摘要： A lot of research efforts have been invested in the fabrication of superhydrophobic surfaces in recent years due to many protentional applications in science and industry including anti-icing, self-cleaning and anti-corrosive surfaces. Laser as a non-polluting, precise and flexible tool can be applied to replicate surface microstructures of extremely water repellent lotus leave surface. In this study, a common nanosecond laser source is used to fabricate a super/ultrahydrophobic surfaces with different microstructure designs, contact angles above 170° and sliding angles below 5°. The freshly processed surface is hydrophilic and becomes hydrophobic and superhydrophobic in a certain time period, which could be dramatically reduced by storing samples in high vacuum. The transformation in wetting properties are analysed with respect to surface geometry and surface chemistry.
关键词： Surface functionalization,fiber laser,vacuum processing,ultrahydrophobicity
更新于2025-09-12 10:27:22
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Surface functionalization under water using picosecond and femtosecond laser pulses – first observations and novel effects
摘要： Functionalization by changing the topography of workpiece surfaces is interesting for many applications. Lasers – especially ultrashort pulse lasers – are flexible tools for this kind of tasks. Besides deterministic structures they allow for processing surfaces in a way that stochastic structures appear. Ripple and spike structures can be fabricated in air. In liquids, however, there are only a few investigations and many open questions. The idea of this paper is to check how water in contact to the workpiece surface affects femtosecond laser surface processing and what kind of structures appear. Results obtained with a picosecond laser are presented for comparison.
关键词： ultrashort pulse laser,surface functionalization,spike structures,material processing in liquids
更新于2025-09-12 10:27:22
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Effects of laser processing conditions on wettability and proliferation of Saos-2 cells on CoCrMo alloy surfaces
摘要： Any processing disturbances in laser surface texturing (LST) could compromise the resulting surface topography and their desired functional response. Disturbances such as focal plane offsets and beam incident angle variations are always present in LST processing of 3D parts and can affect the surface morphology. In this research the effects of these laser processing disturbances in producing laser induced surface structures (LIPSS) on CoCrMo alloy substrates were investigated. In particular, these two disturbances were considered as laser processing variables to determine their effects on functional responses of LIPSS treated surfaces, i.e. surface wettability and the proliferation of Saos-2 osteoblast-like cells were evaluated. It was found that the changes of laser processing conditions led to a decrease in surface wettability and Saos-2 cells proliferation. In addition, a correlation between surface wettability and cell proliferation on LIPSS treated surface was identified and conclusions made about the effects of investigated process disturbances on the functional response of LIPSS treated CoCrMo substrates.
关键词： cobalt chrome molybdenum,surface functionalization,laser induced periodic surface structures,osseointegration,laser surface texturing
更新于2025-09-11 14:15:04
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Vacuum-UV of polyetheretherketone (PEEK) as a surface pre-treatment for structural adhesive bonding
摘要： Polyetheretherketone (PEEK) is known for its poor wettability and poor adhesive properties. Hence, for the creation of reliable high-strength structural adhesive bonded joints, surface treatment of PEEK is required. In this work high strength bondable PEEK surfaces were achieved through a vacuum-UV (VUV) treatment. Samples of amorphous and semi-crystalline PEEK films were exposed to different VUV radiation doses. Additionally oxygen low-pressure plasma (LPP) and untreated (as received) PEEK samples were investigated for comparison. Surfaces were characterized using x-ray photoelectron spectroscopy (XPS), contact angle measurements (CA), atomic force microscopy (AFM) and confocal laser scanning microscopy (CLSM). Tensile tests of the PEEK films were carried out, to investigate changes in the mechanical properties in the bulk of the PEEK films due to the VUV exposure. The adhesive bond strength of treated specimen was determined through two different test methods (tensile and shear). These strengths were compared to the created surface properties. A strong correlation between the contact angle and the creation of functional groups was observed. VUV radiation appears as a suitable pre-treatment method for PEEK, as adhesive bonds of high strength were achieved after 5 seconds. Additionally, the usage of a VUV excimer lamp is simple, cheap and easy for automation.
关键词： X-ray photoelectron spectroscopy,Vacuum-UV (VUV),contact angles,chemical surface functionalization,structural adhesive bonding,Polyetheretherketone (PEEK),atomic force microscopy
更新于2025-09-11 14:12:44
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Gram Scale Synthesis of Isolated Monodisperse Gold Nanorods
摘要： While the gold nanorods (AuNRs) possess a strong potential application in nanotechnology, plasmonics and sensing, the scale-up synthesis of isolated AuNRs in gram quantity remains a challenge. Nearly all previously reported methods produce aqueous solutions of CTAB-coated AuNRs in milligram quantities with the yield of ~20-30 % in terms of Au (I) to Au (0) conversion. In addition, it is difficult to remove CTAB bilayer from the surface of AuNRs and yet make them soluble and functionalized for further processing and chemical modification. This report describes the synthesis of monodisperse functionalized AuNRs (σ~5%) in gram quantities. Our approach is to increase the concentration of HAuCl4.3H20 in the growth solution to produce larger quantities of starting AuNRs and further reduce the remaining Au (I) ions onto the surface of AuNRs. The slow and controlled addition of reducing agent ascorbic acid (AA) continues to Au (0) (via disproportionation reaction) onto the surface of nanorods maintaining their uniform morphology without creating any unwanted impurities of various shapes. In addition, this approach significantly narrows the size distribution due to the continuous growth of partially grown AuNRs during the initial stage of the synthesis. To isolate one-gram quantity of AuNRs and make them functionalized for further chemical reactions, a ligand exchange approach was utilized where surfactant CTAB was replaced with 4-mercaptophenol. The thiol group from 4-mercaptophenol forms a covalent bond to the surface of AuNRs leaving free functional OH groups available for further chemical coupling reactions. For the ligand exchange process, a concentrated solution of 4-mercaptophenol in tetrahydrofuran (THF) solution was introduced into the AuNRs solution. Pure AuNRs, functionalized with 4-mercaptophenol were isolated by dispersion and rinsing with excess of THF, followed by centrifugation.
关键词： Amplification,Surface Functionalization,Gram Scale,Monodisperse,Gold Nanorods
更新于2025-09-10 09:29:36
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Express and portable label-free DNA detection and recognition with SERS platform based on functional Au grating
摘要： Label-free SERS-based detection of DNA is considered as one of the most prospective analytical methods for portable and express bioanalysis. In this work, the SERS platform based on the functional surface plasmon polariton supported ordered structure is proposed as an extremely convenient and effective tool for the detection of specific DNA sequences. The designed SERS structure makes possible DNA analyses in near-real time using the portable Raman spectrometer, with high reproducibility and accuracy of the results and the detection limits of the order of 10-14 M. In order to overcome challenges, connected to meticulous affiliation and evaluation of Raman signals, principal component analysis (PCA) of raw SERS data was used for data evaluation. SERS results reproducibility was achieved through the creation of a periodical structure with homogenous distribution of plasmon energy, when the analysis functionality was implemented through the grafting of the oligonucleotide to gold surface and its further interaction with complementary, mispaired and noncomplementary oligonucleotides. It was demonstrated experimentally that with the SERS platform it is possible not only to detect and recognize pure DNA but also the simultaneous presence of complementary and mispaired DNA with estimation of their relative concentrations. Moreover, the developed SERS sensor demonstrated the perfect stability over 3 months storage period without loss of functionality.
关键词： surface functionalization,DNA recognition,label-free,plasmonic substrate,SERS
更新于2025-09-09 09:28:46
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Simultaneous reduction and surface functionalization of graphene oxide for highly conductive and water dispersible graphene derivatives
摘要： A simple and effective preparation method for the simultaneous reduction and functionalization of graphene oxide (rGO) by 2,4-diamino benzene sulfonic acid has been developed. The derivatives exhibit excellent conductivity and high dispersibility in various solvents. The successful preparation of rGO and the presence of the sulfonated aromatic diamine on rGO surface has been confirmed by infrared and X-ray photoelectron spectroscopy, while, the analysis by micro-Raman spectroscopy indicated that the reduction/functionalization alters the lattice structure of GO by the increment the defect density when the 2,4-diamino benzene sulfonic acid is used. Moreover, the study of the dried products by X-ray diffraction spectroscopy suggested the turbostratic restacking of the exfoliated rGO into graphite-like nanostructures. The obtained derivative of simultaneous reduction and functionalization of GO was used for the preparation of highly conductive water-based gravure ink, which in turn, was successfully applied in printing on various flexible substrates, demonstrating its great potentiality in graphene-based flexible and printed electronics applications.
关键词： Conductive inks,Printed electronics,Surface functionalization,Gravure,Reduced graphene oxide
更新于2025-09-09 09:28:46