Effects of Nano-patterning Modification on the Cell Proliferation and Adhesion in Burn Wound Healing of Regenerated Silk Fibroin Membrane

Objective:To investigate the effect of nano-patterning modification on the cell proliferation and adhesion in burn wound healing of regenerated silk fibroin membrane.Methods:A total of 60 healthy SD mice were randomly divided into three groups:group A received treatment involving nano-patterning on the surface of regenerated silk fibroin membrane,group B received treatment with recombinant human epidermal growth factor gel,and group C received the same treatment with recombinant human epidermal growth factor gel,with 20 cases in each group.Wound healing,surface structure,protein adsorption,cell proliferation and adhesion were assessed at intervals of 5th,15th and 25th d after treatment.Results:The findings indicated that:(1)The duration and pace of wound healing in groups A and B surpassed those of group C,with group A exhibiting superior results compared to group B(P<0.05);(2)Histopathological analysis revealed a progressive increase in neovascularization and fibroblast count in wound tissue across the 5th,15th,and 25th days for all three groups,with group C exhibiting a higher count of neovascularization and fibroblasts in unhealed tissue compared to groups A and B.(3)The levels of basic calponin expression in group A and group B showed an increase on the 5th and 15th day,followed by stabilization on the 25th day.In group C,the expression of basic calponin was initially high on the 5th day,and then stabilized on the 15th and 25th day(P<0.05);(4)The expression of fibroblast proliferating cell nuclear antigen in the wound tissue of mice in all three groups peaked on the 15th day and subsequently declined.The expression of PCNA in group A and group B was higher than that in group C at each time point,with group A exhibiting higher levels than group B(P<0.05);(5)As wounds healed,there was a reduction in apoptotic cells within the wound tissues of mice across three groups,with group a exhibiting a lower count compared to groups B and C(P<0.05).Conclusion:Nanopatterning on the surface of regenerated silk fibroin membrane can enhance the biocompatibility of burn wound treatment and promote the proliferation and adhesion of reparative cells.

Application of nano-patterned InGaN fabricated by selfassembled Ni nano-masks in green InGaN/GaN multiple quantum wells

The nano-patterned InGaN film was used in green InGaN/GaN multiple quantum wells(MQWs)structure,to relieve the unpleasantly existing mismatch between high indium content InGaN and GaN,as well as to enhance the light output.The different self-assembled nano-masks were formed on InGaN by annealing thin Ni layers of different thicknesses.Whereafter,the InGaN films were etched into nano-patterned films.Compared with the green MQWs structure grown on untreated InGaN film,which on nano-patterned InGaN had better luminous performance.Among them the MQWs performed best when 3 nm thick Ni film was used as mask,because that optimally balanced the effects of nano-patterned InGaN on the crystal quality and the light output.

Electroluminescence Orientation in InGaN/GaN LED on Nano-patterned Sapphire by MOCVD

A 385 nm InGaN/GaN LED on the sapphire with the nano-pattem was fabricated and its electroluminescence property was investigated in a three-dimensional （3D） space. The experimental results showed that the luminescent intensity of the LED was obviously oriented based on the nano-pattem of the sapphire substrate. And the optical interference was used to explain the luminescence orientation of the LED on the nano-pattemed substrate.

Evolution of microstructure, stress and dislocation of AlN thick film on nanopatterned sapphire substrates by hydride vapor phase epitaxy

A crack-free AlN film with 4.5 μm thickness was grown on a 2-inch hole-type nano-patterned sapphire substrates(NPSSs) by hydride vapor phase epitaxy(HVPE). The coalescence, stress evolution, and dislocation annihilation mechanisms in the AlN layer have been investigated. The large voids located on the pattern region were caused by the undesirable parasitic crystallites grown on the sidewalls of the nano-pattern in the early growth stage. The coalescence of the c-plane AlN was hindered by these three-fold crystallites and the special triangle void appeared. The cross-sectional Raman line scan was used to characterize the change of stress with film thickness, which corresponds to the characteristics of different growth stages of AlN. Threading dislocations(TDs) mainly originate from the boundary between misaligned crystallites and the c-plane AlN and the coalescence of two adjacent c-plane AlN crystals, rather than the interface between sapphire and AlN.

Sorting Gold and Sand(Silica) Using Atomic Force Microscope-Based Dielectrophoresis

Additive manufacturing-also known as 3D printing-has attracted much attention in recent years as a powerful method for the simple and versatile fabrication of complicated three-dimensional structures.However,the current technology still exhibits a limitation in realizing the selective deposition and sorting of various materials contained in the same reservoir,which can contribute significantly to additive printing or manufacturing by enabling simultaneous sorting and deposition of different substances through a single nozzle.Here,we propose a dielectrophoresis(DEP)-based material-selective deposition and sorting technique using a pipette-based quartz tuning fork(QTF)-atomic force microscope(AFM) platform DEPQA and demonstrate multi-material sorting through a single nozzle in ambient conditions.We used Au and silica nanoparticles for sorting and obtained 95% accuracy for spatial separation,which confirmed the surfaceenhanced Raman spectroscopy(SERS).To validate the scheme,we also performed a simulation for the system and found qualitative agreement with the experimental results.The method that combines DEP,pipette-based AFM,and SERS may widely expand the unique capabilities of 3D printing and nano-micro patterning for multi-material patterning,materials sorting,and diverse advanced applications.

Bacterial Surface Layer Proteins: A Promising Nano-Technological Tool for Bio-Sensing Applications

The phenomenal rise in the demand of biosensors accelerated their rapid development and immersive applications in the myriads of fields. The essential requirement of developing efficient bio-sensing platform is to find stable well organized interfacial architecture that can serve as an excellent matrix for binding and recognizing biomolecules. In this context, the enormous potential has been envisaged in surface layer proteins that represented themselves as most primitive and simplest self-assembled system with repetitive physicochemical properties for the molecular functionalization of surfaces and various interfaces. The prominence of S-layer proteins has been broadened by integrating genetic engineering approaches for the fine tuning of functional groups and protein domains in geometrically well-defined manner. The efficient and stable binding of various nanomaterials with S-layers in regular arrays has led to paradigmatic shift in their nano-biotechnological sensing applications. More recently, functional S-layer supported lipid membranes have been generated through covalent binding of lipid molecules either with native or recombinant S-layer proteins at nano-scale dimensions serving as “proof of concept” for the development of bio-sensing platform. Thus, in the light of benefits conferred by surface layer proteins for the development of highly efficient biosensors, an exciting path has been opened for broadening their translational applications in drug delivery, disease diagnosis, vaccines development, lab-on-chip devices etc. Therefore, this review intends to describe about the importance of surface layer proteins in the development of biosensors.

Fabrication of Anti-reflecting Si Nano-structures with Low Aspect Ratio by Nano-sphere Lithography Technique

Nano-structured photon management is currently an interesting topic since it can enhance the optical absorption and reduce the surface reflection which will improve the performance of many kinds of optoelectronic devices, such as Si-based solar cells and light emitting diodes. Here, we report the fabrication of periodically nano-patterned Si structures by using polystyrene nano-sphere lithography technique. By changing the diameter of nano-spheres and the dry etching parameters, such as etching time and etching power, the morphologies of formed Si nano-structures can be well controlled as revealed by atomic force microscopy.A good broadband antireflection property has been achieved for the formed periodically nano-patterned Si structures though they have the low aspect ratio(<0.53). The reflection can be significantly reduced compared with that of flat Si substrate in a wavelength range from 400 nm to 1200 nm. The weighted mean reflection under the AM1.5 solar spectrum irradiation can be as low as 3.92% and the corresponding optical absorption is significantly improved, which indicates that the present Si periodic nano-structures can be used in Si-based thin film solar cells.

Progress and prospects of GaN-based LEDs using nanostructures

Progress with GaN-based light emitting diodes （LEDs） that incorporate nanostructures is reviewed, especially the re- cent achievements in our research group. Nano-patterned sapphire substrates have been used to grow an A1N template layer for deep-ultraviolet （DUV） LEDs. One efficient surface nano-texturing technology, hemisphere-cones-hybrid nanostruc- tures, was employed to enhance the extraction efficiency of InGaN flip-chip LEDs. Hexagonal nanopyramid GaN-based LEDs have been fabricated and show electrically driven color modification and phosphor-free white light emission because of the linearly increased quantum well width and indium incorporation from the shell to the core. Based on the nanostruc- tures, we have also fabricated surface plasmon-enhanced nanoporous GaN-based green LEDs using AAO membrane as a mask. Benefitting from the strong lateral SP coupling as well as good electrical protection by a passivation layer, the EL intensity of an SP-enhanced nanoporous LED was significantly enhanced by 380%. Furthermore, nanostructures have been used for the growth of GaN LEDs on amorphous substrates, the fabrication of stretchable LEDs, and for increasing the 3-dB modulation bandwidth for visible light communication.

GaN grown on nano-patterned sapphire substrates

High-quality gallium nitride （GaN） film was grown on nano-pattemed sapphire substrates （NPSS） and investigated using XRD and SEM. It was found that the optimum thickness of the GaN bulter layer on the NPSS is 15 nm, which is thinner than that on micro-patterned sapphire substrates （MPSS）. An interesting phenomenon was observed for GaN film grown on NPSS：GaN mainly grows on the trench regions and little grows on the sidewalls of the patterns at the initial growth stage, which is dramatically different from GaN grown on MPSS. In addition. the electrical and optical properties of LEDs grown on NPSS were characterized.

Different micro/nano-scale patterns of surface materials influence osteoclastogenesis and actin structure

The surface topography of a material can influence osteoclast activity.However,the surface structural factors that promote osteoclast activity have not yet been investigated in detail.Therefore,we investigated osteoclastogenesis by testing various defined patterns with different dimensions and shapes.The systematic patterns,made of a cyclo-olefin polymer,were prepared at a micron-,submicron-,and nano-scale with a groove,hole,or pillar shape with a 1:1 pitch ratio.RAW264.7 cells were cultured on these patterns in the presence of the receptor activator of NF-κB ligand(RANKL).Osteoclast formation was induced in the order:pillar>groove≥hole.The two-dimensional factors also indicated that submicron-sized patterns strongly induced osteoclast formation.The optimal pillar dimension for osteoclast formation was 500 nm in diameter and 2μm in height.Furthermore,we observed two types of characteristic actin structure,i.e.,belt-like structures with small hollow circles and isolated ring-like structures,which formed on or around the pillars depending on size and height.Furthermore,resorption pits were observed mainly on the top of calcium phosphate-coated pillars.Thus,osteoclasts prefer convex shapes,such as pillars for differentiation and resorption.Our results indicate that osteoclastogenesis can be controlled by designing surfaces with specific morphologies.