Surface Functionalization of Microporous Polypropylene Membrane with Polyols for Removal of Boron Acid from Aqueous Solution

Affinity membranes are fabricated for boric acid removal by the surface functionalization of microporous polypropylene membrane(MPPM)with lactose-based polyols.The affinity is based on specific complexation between boric acid and saccharide polyols.A photoinduced grafting-chemical reaction sequence was used to prepare these affinity membranes.Poly(2-aminoethyl methacrylate hydrochloride)[poly(AEMA)]was grafted on the surfaces of MPPM by UV-induced graft polymerization.Grafting in the membrane pores was visualized by dying the cross-section of poly(AEMA)-grafted MPPM with fluorescein disodium and imaging with confocal laser scanning microscopy.It is concluded that lactose ligands can be covalently immobilized on the external surface and in the pores by the subsequent coupling of poly(AEMA)with lactobionic acid(LA).Physical and chemical properties of the affinity membranes were characterized by field emission scanning electron microscopy and Fourier Transform Infrared/Attenuated Total Refraction spectroscopy(FT-IR/ATR).3-Aminophenyl boric acid(3-APBA)was removed from aqueous solution by a single piece of lactose-functionalized MPPM in a dynamic filtration system.The results show that the 3-APBA removal reaches an optimal efficiency(39.5%)under the alkaline condition(pH9.1),which can be improved by increasing the immobilization density of LA.Regeneration of these affinity membranes can be easily realized through acid-base washing because the complexation of boric acid and saccharide polyol is reversible.

The role of surface functionalization of silica nanoparticles for bioimaging

Among the several types of inorganic nanoparticles available,silica nanoparticles(SNP)have earned their relevance in biological applications namely,as bioimaging agents.In fact,uorescent SNP(FSNP)have been explored in this-eld as protective nanocarriers,overcoming some limitations presented by conventional organic dyes such as high photobleaching rates.A crucial aspect on the use of uorescent SNP relates to their surface properties,since it determines the extent of interaction between nanoparticles and biological systems,namely in terms of colloidal stability in water,cellular recognition and internalization,tracking,biodistribution and speci-city,among others.Therefore,it is imperative to understand the mechanisms underlying the interaction between biosystems and the SNP surfaces,making surface functionalization a relevant step in order to take full advantage of particle properties.The versatility of the surface chemistry on silica platforms,together with the intrinsic hydrophilicity and biocompatibility,make these systems suitable for bioimaging applications,such as those mentioned in this review.

Surface functionalization of SPR chip for specific molecular interaction analysis under flow condition

Surface functionalization of sensor chip for probe immobilization is crucial for the biosensing applications of surface plasmon resonance(SPR)sensors.In this paper,we report a method circulating the dopamine aqueous solution to coat polydopamine film on sensing surface for surface functionalization of SPR chip.The polydopamine film with available thickness can be easily prepared by controlling the circulation time and the biorecognition elements can be immobilized on the polydopamine film for specific molecular interaction analysis.These opera-tions are all performed under flow condition in the fuidic system,and have the advantages of easy implementation,less time consuming,and low cost,because the reagents and devices used in the operations are routinely applied in most laboratories.In this study,the specific absorption between the protein A probe immobilized on the sensing surface and human immunoglobulin G in the buffer is monitored based on this surface functionalization strategy to demonstrated its feasibility for SPR biosensing applications.

Laser surface functionalization to achieve extreme surface wetting conditions and resultant surface functionalities

Wetting condition of micro/nanostructured surface has received tremendous attention due to the potential applications in commercial,industrial,and military areas.Surfaces with extreme wetting properties,e.g.,superhydrophobic or superhydrophilic,are extensively employed due to their superior anti-icing,drag reduction,enhanced boiling heat transfer,self-cleaning,and anti-bacterial properties depending on solid-liquid interfacial interactions.Laser-based techniques have gained popularity in recent years to create micro/nano-structured surface owing to their high flexibility,system precision,and ease for automation.These techniques create laser induced periodic surface structures(LIPSS)or hierarchical structures on substrate material.However,micro/nanostructures alone cannot attain the desired wettability.Subsequent modification of surface chemistry is essentially needed to achieve target extreme wettability.This review paper aims to provide a comprehensive review for both laser texturing techniques and the following chemistry modification methods.Recent research progress and fundamental mechanisms of surface structure generation via different types of lasers and various chemistry modification methods are discussed.The complex combination between the laser texturing and surface chemistry modification methods to decide the final wetting condition is presented.More importantly,surface functionalities of these surfaces with extreme wetting properties are discussed.Lastly,prospects for future research are proposed and discussed.

Molecular surface functionalization of In_(2)O_(3) to tune interfacial microenvironment for enhanced catalytic performance of CO_(2) electroreduction

Indium-based materials(e.g.,In_(2)O_(3))are a class of promising non-noble metal-based catalysts for electroreduction of carbon dioxide(CO_(2)).However,competitive hydrogen reduction reaction(HER)on indium-based catalysts hampers CO_(2) reduction reaction(CO_(2)RR)process.We herein tune the interfacial microenvironment of In_(2)O_(3) through chemical graft of alkyl phosphoric acid molecules using a facile solution-processed strategy for the first time,which is distinguished from other researches that tailor intrinsic activity of In_(2)O_(3) themselves.The surface functionalization of alkyl phosphoric acids over In_(2)O_(3) is demonstrated to remarkably boost CO_(2) conversion.For example,octadecylphosphonic acid modified In_(2)O_(3) exhibits Faraday efficiency for H_(2) H_(2) H_(2)(FE)of as low as 6.6%and FEHCOOH of 86.5%at-0.67 V vs.RHE,which are far superior to parent In_(2)O_(3) counterparts(FE of 24.0%and FEHCOOH of 63.1%).Moreover,the enhancing effect of alkyl phosphoric acid functionalization is found to be closely related to the length of alkyl chains.By virtue of comprehensive experimental characterizations and molecular dynamics simulations,it is revealed that the modification of alkyl phosphoric acids significantly alters the interface microenvironment of the electrocatalyst,which changes the electrocatalyst surface from hydrophilic and aerophobic to hydrophobic and aerophilic.In this case,the water molecules are pushed away and more CO_(2) molecules are trapped,increasing local CO_(2) concentration at In_(2)O_(3) active sites,thus leading to the significantly enhanced CO_(2)RR and suppressed HER.This work highlights the importance of regulating the interfacial microenvironment of inorganic catalysts by molecular surface functionalization as a means for promoting the electrochemical performance in electrosynthesis and beyond.

3D Printing of Tough Hydrogel Scaffolds with Functional Surface Structures for Tissue Regeneration

Hydrogel scaffolds have numerous potential applications in the tissue engineering field.However,tough hydrogel scaffolds implanted in vivo are seldom reported because it is difficult to balance biocompatibility and high mechanical properties.Inspired by Chinese ramen,we propose a universal fabricating method(printing-P,training-T,cross-linking-C,PTC&PCT)for tough hydrogel scaffolds to fill this gap.First,3D printing fabricates a hydrogel scaffold with desired structures(P).Then,the scaffold could have extraordinarily high mechanical properties and functional surface structure by cycle mechanical training with salting-out assistance(T).Finally,the training results are fixed by photo-cross-linking processing(C).The tough gelatin hydrogel scaffolds exhibit excellent tensile strength of 6.66 MPa(622-fold untreated)and have excellent biocompatibility.Furthermore,this scaffold possesses functional surface structures from nanometer to micron to millimeter,which can efficiently induce directional cell growth.Interestingly,this strategy can produce bionic human tissue with mechanical properties of 10 kPa-10 MPa by changing the type of salt,and many hydrogels,such as gelatin and silk,could be improved with PTC or PCT strategies.Animal experiments show that this scaffold can effectively promote the new generation of muscle fibers,blood vessels,and nerves within 4 weeks,prompting the rapid regeneration of large-volume muscle loss injuries.

Plenty more room on the glass bottom： Surface functionalization and nanobiotechnology for cell isolation

Surface functionalization is a widely adopted technique for surface modification which allows researchers to customize surfaces to integrate with their research. Surface functionalization has been used recently to adapt surfaces to integrate with biological materials specifically to isolate cells or mimic biological tissues through cell patterning. Cell isolation and cell patterning both can be integrated with extant techniques or surfaces to customize the research to whatever needs to be tested. Substrates such as metals, biologically mimicking surfaces, environmental responsive surfaces, and even three-dimensional surfaces such as hydrogels have all been adapted to allow for functionalization for both patterning and isolation. In this review we have described both the advantages and disadvantages of these techniques and the related chemistries to better understand these tools and how best to apply them in the hope that we can further expand upon the research in the field.

Bioinspired surface functionalization of biodegradable mesoporous silica nanoparticles for enhanced lubrication and drug release

Osteoarthritis is associated with the significantly increased friction of the joint,which results in progressive and irreversible damage to the articular cartilage.A synergistic therapy integrating lubrication enhancement and drug delivery is recently proposed for the treatment of early-stage osteoarthritis.In the present study,bioinspired by the self-adhesion performance of mussels and super-lubrication property of articular cartilages,a biomimetic self-adhesive dopamine methacrylamide-poly(2-methacryloyloxyethyl phosphorylcholine)(DMA-MPC)copolymer was designed and synthesized via free radical polymerization.The copolymer was successfully modified onto the surface of biodegradable mesoporous silica nanoparticles(bMSNs)by the dip-coating method to prepare the dual-functional nanoparticles(bMSNs@DMA-MPC),which were evaluated using a series of surface characterizations including the transmission electron microscope(TEM),Fourier transform infrared(FTIR)spectrum,thermogravimetric analysis(TGA),X-ray photoelectron spectroscopy(XPS),etc.The tribological test and in vitro drug release test demonstrated that the developed nanoparticles were endowed with improved lubrication performance and achieved the sustained release of an anti-inflammatory drug,i.e.,diclofenac sodium(DS).In addition,the in vitro biodegradation test showed that the nanoparticles were almost completely biodegraded within 10 d.Furthermore,the dual-functional nanoparticles were biocompatible and effectively reduced the expression levels of two inflammation factors such as interleukin-1β(IL-1β)and interleukin-6(IL-6).In summary,the surface functionalized nanoparticles with improved lubrication and local drug release can be applied as a potential intra-articularly injected biolubricant for synergistic treatment of early-stage osteoarthritis.

Surface Functionalization of PEO Nanofibers Using a TiO_(2) Suspension as Sheath Fluid in a Modified Coaxial Electrospinning Process

Convenient and integration fabrication process is a key issue for the application of functional nanofibers.A surface functionalization method was developed based on coaxial electrospinning to produce ultraviolet(UV)protection nanofibers.The titanium dioxide(TiO_(2))nanoparticles suspension was delivered through the shell channel of the coaxial spinneret,by which the aggregation of TiO_(2) nanoparticles was overcome and the distribution uniformity on the surface of polyethylene oxide(PEO)nanofiber was obtained.With the content of TiO_(2) increasing from 0 to 3%(mass fraction),the average diameter of nanofibers increased from(380±30)nm to(480±100)nm.The surface functionalization can be realized during the electrospinning process to gain PEO/TiO_(2) composite nanofibers directly.The uniform distribution of TiO_(2) nanoparticles on the surface of nanofibers enhanced the UV absorption and resistance performance.The maximum UV protection factor(UPF)value of composite nanofibers reaches 2751.This work presented a novel surface-functionalized way for the preparation of composite nanofiber,which has great application potential in the field of micro/nano system integration fabrication.

SURFACE FUNCTIONALIZATION OF POLYSTYRENE TO BIND WITH FMRF PEPTIDES FOR NOVEL BIOCOMPATIBILITY

A generic method was described to change surface biocompatibihty by introducing reactive functional groups onto surfaces of polymeric substrates and covalently binding them with biomolecules.A block copolymer with protected carboxylic acid functionality,poly（styrene-b-tert-butyl acrylate）（PS-PtBA）,was spin coated from solutions in toluene on a bioinert polystyrene（PS） substrate to form a bilayer structure：a surface layer of the poly（tert-butyl acrylate）（PtBA） blocks that order at the air-polymer interface and a bottom layer of the PS blocks that entangle with the PS substrate.The thickness of the PtBA layer and the area density of tert-butyl ester groups of PtBA increased linearly with the concentration of the spin coating solution until a 2 nm saturated monolayer coverage of PtBA was achieved at the concentration of 0.4%W/W.The protected carboxylic acid groups were generated by exposing the tert-butyl ester groups of PtBA to trifluoroacetic acid （TFA） for bioconjugation with FMRF peptides via amide bonds.The yield of the bioconjugation reaction for the saturated surface was calculated to be 37.1%based on X-ray photoelectron spectroscopy（XPS） measurements.The success of each functionalization step was demonstrated and characterized by XPS and contact angle measurements.This polymer functionalization/modification concept can be virtually applied to any polymeric substrate by choosing appropriate functional block copolymers and biomolecules to attain novel biocompatibility.

A facile strategy for tuning the density of surface-grafted biomolecules for melt extrusion-based additive manufacturing applications

Melt extrusion-based additive manufacturing(ME-AM)is a promising technique to fabricate porous scaffolds for tissue engi-neering applications.However,most synthetic semicrystalline polymers do not possess the intrinsic biological activity required to control cell fate.Grafting of biomolecules on polymeric surfaces of AM scaffolds enhances the bioactivity of a construct;however,there are limited strategies available to control the surface density.Here,we report a strategy to tune the surface density of bioactive groups by blending a low molecular weight poly(ε-caprolactone)5k(PCL5k)containing orthogonally reactive azide groups with an unfunctionalized high molecular weight PCL75k at different ratios.Stable porous three-dimensional(3D)scaf-folds were then fabricated using a high weight percentage(75 wt.%)of the low molecular weight PCL 5k.As a proof-of-concept test,we prepared films of three different mass ratios of low and high molecular weight polymers with a thermopress and reacted with an alkynated fluorescent model compound on the surface,yielding a density of 201-561 pmol/cm^(2).Subsequently,a bone morphogenetic protein 2(BMP-2)-derived peptide was grafted onto the films comprising different blend compositions,and the effect of peptide surface density on the osteogenic differentiation of human mesenchymal stromal cells(hMSCs)was assessed.After two weeks of culturing in a basic medium,cells expressed higher levels of BMP receptor II(BMPRII)on films with the conjugated peptide.In addition,we found that alkaline phosphatase activity was only significantly enhanced on films contain-ing the highest peptide density(i.e.,561 pmol/cm^(2)),indicating the importance of the surface density.Taken together,these results emphasize that the density of surface peptides on cell differentiation must be considered at the cell-material interface.Moreover,we have presented a viable strategy for ME-AM community that desires to tune the bulk and surface functionality via blending of(modified)polymers.Furthermore,the use of alkyne-azide“click”chemistry enables spatial control over bioconjugation of many tissue-specific moieties,making this approach a versatile strategy for tissue engineering applications.

Double-sided surface functionalization: An effective approach to stabilize and modulate the electronic structure of graphene-like borophene

Graphene-like borophene was theoretically proposed and recently synthesized on Al(111)surface,however,how to conquer its structural instability is still an open question.By means of density functional theory computations,we theoretically predicted that honeycomb borophene can be well stabilized by double-sided surface passivation with monovalent functional groups(X=F,Cl,Br,I,OH,and NH2)due to the electron redistributions.The system undergoes the transition from metallic to semiconducting upon functionalization,while the energy gap depends on the choice of functional groups.Under external strain,the gap values can be manipulated over a broad range.Our further calculations indicated that the functionalized borophene possesses moderate and anisotropic carrier mobility,which is comparable to or even higher than some 2D materials such as MoS2 and phosphorene.Our work provides a feasible strategy to effectively stabilize the graphene-like borophene and tune the electronic properties with great potentials for electronic applications.

Review on the Fabrication of Surface Functional Structures for Enhancing Bioactivity of Titanium and Titanium Alloy Implants

Titanium and its alloys have been widely applied in many biomedical fields because of its excellent mechanical properties,corrosion resistance and good biocompatibility.However,problems such as rejection,shedding and infection will occur after titanium alloy implantation due to the low biological activity of titanium alloy surface.The structures with specific functions,which can enhance osseointegration and antibacterial properties,are fabricated on the surface of titanium implants to improve the biological activity between the titanium implants and human tissues.This paper presents a comprehensive review of recent developments and applications of surface functional structure in titanium and titanium alloy implants.The applications of surface functional structure on different titanium and titanium alloy implants are introduced,and their manufacturing technologies are summarized and compared.Furthermore,the fabrication of various surface functional structures used for titanium and titanium alloy implants is reviewed and analyzed in detail.Finally,the challenges affecting the development of surface functional structures applied in titanium and titanium alloy implants are outlined,and recommendations for future research are presented.

Selective removal of heavy metal ions from aqueous solutions with surface functionalized silica nanoparticles by different functional groups

The industrial silica fume pretreated by nitric acid at 80 °C was re-used in this work. Then, the obtained silica nanoparticles were surface functionalized by silane coupling agents, such as(3-Mercaptopropyl) triethoxysilane(MPTES) and(3-Amincpropyl) trithoxysilane(APTES). Some further modifications were studied by chloroaceetyl choride and 1,8-Diaminoaphalene for amino modified silica. The surface functionalized silica nanoparticles were characterized by Fourier transform infrared(FI-IR) and X-ray photoelectron spectroscopy(XPS). The prepared adsorbent of surface functionalized silica nanoparticles with differential function groups were investigated in the selective adsorption about Pb2+, Cu2+, Hg2+, Cd2+ and Zn2+ions in aqueous solutions. The results show that the(3-Mercaptopropyl) triethoxysilane functionalized silica nanoparticles(SiO2-MPTES) play an important role in the selective adsorption of Cu2+ and Hg2+, the(3-Amincpropyl) trithoxysilane(APTES) functionalized silica nanoparticles(SiO2-APTES) exhibited maximum removal efficiency towards Pb2+ and Hg2+, the 1,8-Diaminoaphalene functionalized silica nanoparticles was excellent for removal of Hg2+ at room temperature, respectively.

Basic Functionalization of Hexagonal Mesoporous Silica

Aminopropyltriethoxysilane (AM), 3-ethyldiaminopropyltrimethoxysilane (ED) and 3-piperazinylpropyltriethoxysilane (PZ), were used to chemically couple with the silanol groups of calcined hexagonal and hexagonal-like mesoporous silica SBA-3 and HMS, respectively, to produce functionalised alkaline mesoporous materials. The increase in the dosage of organosilanes, or in reaction temperature, or in the humidity (i.e., water content) of support, is favorable to the grafting of functional molecules on the surface. When functionalization conditions are the same, the order of loadings on SBA-3 and DDA-HMS is ED>AM>PZ. However, on ODA-HMS, the loading of AM is similar to that of ED.

Ultrashort pulsed laser induced complex surface structures generated by tailoring the melt hydrodynamics

We present a novel approach for tailoring the laser induced surface topography upon femtosecond(fs)pulsed laser irradiation.The method employs spatially controlled double fs laser pulses to actively regulate the hydrodynamic microfluidic motion of the melted layer that gives rise to the structures formation.The pulse train used,in particular,consists of a previously unexplored spatiotemporal intensity combination including one pulse with Gaussian and another with periodically modulated intensity distribution created by Direct Laser Interference Patterning(DLIP).The interpulse delay is appropriately chosen to reveal the contribution of the microfluidic melt flow,while it is found that the sequence of the Gaussian and DLIP pulses remarkably influences the surface profile attained.Results also demonstrate that both the spatial intensity of the double pulse and the effective number of pulses per irradiation spot can further be modulated to control the formation of complex surface morphologies.The underlying physical processes behind the complex patterns’generation were interpreted in terms of a multiscale model combining electron excitation with melt hydrodynamics.We believe that this work can constitute a significant step forward towards producing laser induced surface structures on demand by tailoring the melt microfluidic phenomena.

Structural characteristics of surface-functionalized nitrogen-doped diamond-like carbon films and effective adjustment to cell attachment

Nitrogen-doped diamond-like carbon （DLC：N） films prepared by the filtered cathodic vacuum arc technology are functionalized with various chemical molecules including dopamine （DA）, 3-Aminobenzeneboronic acid （APBA）, and adenosine triphosphate （ATP）, and the impacts of surface functionalities on the surface morphologies, compositions, microstructures, and cell compatibility of the DLC：N films are systematically investigated. We demonstrate that the surface groups of DLC：N have a significant effect on the surface and structural properties of the film. The activity of PC12 cells depends on the particular type of surface functional groups of DLC：N films regardless of surface roughness and wettability. Our research offers a novel way for designing functionalized carbon films as tailorable substrates for biosensors and biomedical engineering applications.

Extremum response surface method of reliability analysis on two-link flexible robot manipulator

In order to present a new method for analyzing the reliability of a two-link flexible robot manipulator,Lagrange dynamics differential equations of the two-link flexible robot manipulator were established by using the integrated modal method and the multi-body system dynamics method.By using the Monte Carlo method,the random sample values of the dynamic parameters were obtained and Lagrange dynamics differential equations were solved for each random sample value which revealed their displacement,speed and acceleration.On this basis,dynamic stresses and deformations were obtained.By taking the maximum values of the stresses and the deformations as output responses and the random sample values of dynamic parameters as input quantities,extremum response surface functions were established.A number of random samples were then obtained by using the Monte Carlo method and then the reliability was analyzed by using the extremum response surface method.The results show that the extremum response surface method is an efficient and fast reliability analysis method with high-accuracy for the two-link flexible robot manipulator.

Effect of acidic surface functional groups on Cr(Ⅵ) removal by activated carbon from aqueous solution

The activated carbon with high surface area was prepared by KOH activation.It was further modified by H2SO4 and HNO3 to introduce more surface functional groups.The pore structure of the activated carbons before and after modification was analyzed based on the nitrogen adsorption isotherms.The morphology of those activated carbons was characterized using scanning electronic microscopy （SEM）.The surface functional groups were determined by Fourier transform infrared spectroscopy （FTIR）.The quantity of those groups was measured by the Boehm titration method.Cr（VI） removal by the activated carbons from aqueous solution was investigated at different pH values.The results show that compared with H2SO4,HNO3 destructs the original pore of the activated carbon more seriously and induces more acidic surface functional groups on the activated carbon.The pH value of the solution plays a key role in the Cr（VI） removal.The ability of reducing Cr（VI） to Cr（III） by the activated carbons is relative to the acidic surface functional groups.At higher pH values,the Cr（VI） removal ratio is improved by increasing the acidic surface functional groups of the activated carbons.At lower pH values,however,the acidic surface functional groups almost have no effect on the Cr（VI） removal by the activated carbon from aqueous solution.

Synthesis of fractal geometry and CAGD models for multi-scale topography modelling of functional surfaces

In order to support the functional design and simulation and the final fabrication processes for functional surfaces,it is necessary to obtain a multi-scale modelling approach representing both macro geometry and micro details of the surface in one unified model.Based on the fractal geometry theory,a synthesized model is proposed by mathematically combining Weierstrass-Mandelbrot fractal function in micro space and freeform CAGD model in macro space.Key issues of the synthesis,such as algorithms for fractal interpolation of freeform profiles,and visualization optimization for fractal details,are addressed.A prototype of the integration solution is developed based on the platform of AutoCAD's Object ARX,and a few multi-scale modelling examples are used as case studies.With the consistent mathematic model,multi-scale surface geometries can be represented precisely.Moreover,the visualization result of the functional surfaces shows that the visualization optimization strategies developed are efficient.