Modification Of Functional Groups Research Articles

Setting behavior, apatite-forming ability, mechanical strength of polymethylmethacrylate bone cement through bioactivity modification of phosphate functional groups combined with Ca2+ ions

Bioactivity modification helps polymethylmethacrylate (PMMA) bone cement to reinforce its interfacial adhesion to bone tissues through the chemical bonding of apatite. Since Si-OH groups combined with Ca2+ ions have succeeded in inducing apatite formation, more combinations of functional groups and active ions are being explored. In this study, Bis[2-(methacryloyloxy)ethyl] phosphate (B2meP) containing phosphate (=PO4H) groups and Ca(CH3COO)2 supplying Ca2+ ion were adopted to investigate the feasibility of equipping PMMA bone cement with apatite-forming ability in vitro, more effects under designed contents on setting behavior, injectability, contact angle, cytotoxicity and mechanical strength were also investigated. Results showed B2meP copolymerized with MMA and became one section of PMMA chains, surface = PO4H groups and released Ca2+ ions pushed spherical apatite individuals nucleating and agglomerating into layer horizontally, Increasing B2meP content lowered the contact angle and the peak temperature, enhanced the cell viability of MC3T3-E1, but prolonged apatite forming period. Injectability rate performed a similar trend to setting time. Lower adding content and deposited apatite layer contributed to reduce the strength loss in soaking. Taking biological performance and other properties into balance, cement added with B2meP of 10 wt% in MMA and Ca(CH3COO)2 of 20 wt% in PMMA performed better.

Mussel-inspired polydopamine functionalized recyclable coconut shell derived carbon nanocomposites for efficient adsorption of methylene blue

Relatively cheap or at no cost, easily available, renewable agricultural waste has been given a new purpose. Using coconut shells as the raw material, and being obtained from agricultural, industry by-products, or even waste materials were used as carbon resource. Acid etching coconut shells carbon (AC) rendered micro/nanoscale hierarchical structures and made the surface available for further modification. Then, the surface of acidified coconut shell carbon was engineered via mussel inspired chemistry. The polydopamine functionalized AC composites (AC-PDA) were applied for efficient removal of methylene blue (MB) dye. Further, the surface morphology, and chemical structure were evaluated by means of scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FT-IR). Through the combination of acid etching and mussel inspired chemistry, organic functional groups can be successfully introduced onto the surface of the coconut shells carbon. The improvement of adsorption capacity of AC-PDA compared with AC is probably due to the increased number of active binding sites resulting from surface modification and formation of new functional groups.

A facile chemical cross-linking approach toward the fabrication of a sustainable porous ulvan scaffold

Ulvans represent one of the most abundant marine-derived macromolecular sulfated polysaccharides accounting for numerous biological applications including in one of the fastest growing field of biomedical sciences. Tissue engineering based on biologically inspired and naturally derived polymers has been one of the prime focuses of regenerative medicine. The present investigation is intended to explore an ionic cross-linking approach at higher pH lead by the calcium ions for casting cell growth promoting scaffolds out of the raw ulvan. The characterization studies using attenuated total reflectance infrared spectroscopy represent specific absorptions at 2950, 980, and 600 cm−1, whereas the x-ray diffraction showed a total absence of major crystalline peaks presenting significant shift to an amorphous state. The 1H nuclear magnetic resonance study revealed functional group modifications in the backbone that might be potentially derived from calcium interactions with glucurorhamnose 3-sulfate and iduronorhamnose 3-sulfate. The atomic force microscopy together with field emission scanning electron microscopy and energy dispersive x-ray spectroscopy mapping revealed the resultant surface changes, whereas confocal microscopy z-stacking showed the cell proliferative activity as evident by the attainment of complete morphology. The combined chemical and biological response of the scaffold makes it a well suitable support for its cell culture and tissue engineering applications.

Comparative Evaluation of Chemical Treatment on the Physical and Mechanical Properties of Areca Frond, Banana, and Flax Fibers

ABSTRACT The present work aims to understand the effect of chemical treatment on the physical and mechanical characteristics of the natural fibers, namely, areca frond fibers, banana, and flax fibers. Chemical reagents viz. sodium bicarbonate, potassium permanganate, and chromium sulfate were used for surface modifications. Tensile strength of the fibers was determined for analyzing the influence of treatments. Scanning electron microscopy was adopted to visualize the surface morphology. Fourier transform infrared spectroscopy was performed on the fiber specimen to interpret functional group modifications. The research results indicated a decrease in fiber diameter with increase in density of fibers post treatments. For areca frond and flax fibers, chromium sulfate treatment was the most effective while that for banana fibers sodium bicarbonate based treatment turned out to be most effective over the others. Scanning electron microscopy images confirmed clear visibility of fiber inner cell structure, protruding secondary fibrils for treated fibers, reagent coating on the fiber surface was also observed in the case of chromium sulfate-treated samples. Fourier transform infrared spectroscopy analysis showed distinct bands indicating functional group modifications corresponding to cellulose, hemicellulose, and lignin.

The mechanism of V-modification in Li2CoSiO4 cathode material for Li-ion batteries: A combined first-principles and experimental study

Lithium cobalt silicate Li2CoSiO4 (LCSO) is a unique cathode candidate that has the potential to simultaneously achieve both high energy-density and high safety. However, it was plagued with poor electrochemical performances owing to limited effective modification of its polymorphic and electronic structures. Functional groups modification has long been proven to be effective approaches for enhancing chemical/physical properties that are highly desirable for energy storage systems. Here the multivalent vanadium (V) doping to modify the tetrahedral functional groups in LCSO was proposed. Based on density functional theory calculations and experimental analysis, V prefers to be doped at Si site, which improves both the electronic and ionic conductivities of LCSO. First-principles modeling with Madelung matrix analysis reveals that the V3d-O2p orbital overlaps largely account for the reduction of the electronic energy gap by ∼1.40 eV and the lithium migration energy barrier by ∼0.20 eV Li2CoV0.1Si0.9O4/C shows the highest initial discharge capacity of 220.1 mAh g−1, compared to only 135.0 mAh g−1 for Li2CoSiO4/C. The discharge rate and cycling stability are also improved. Electrochemical impedance spectroscopy indicates that charge transfer resistance and Li diffusion resistance are reduced by 22.8% and 53.2%, respectively, after V-modification.

Silver and titanium oxides for the removal of phenols from pharmaceutical wastewater

This study is focused on the removal of total phenols from pharmaceutical effluent using an adsorbent of silver and titanium oxides-doped activated carbon. The adsorbent was biosynthesized by reducing AgNO3 and Ti (NO3)4·4H2O into their oxides by whole extracts of Shea butter leaves and subsequently doped on activated carbon. The properties of the adsorbent were investigated for its morphology, elemental composition, crystallinity, and surface functional group modifications using HRSEM, EDS, XRD, and FTIR respectively. It was found to exhibit high crystallinity from rutile titania, with particle sizes in the sub – 200 nm range, and surface-modified with aromatics, nitrates, and nitramines that favor adsorption. Batch adsorption studies were performed at different contact time (20–230 min.), temperature (35–50 °C), and adsorbent dosage (0.1–0.5 g/50 mL). An optimum percent phenol removal of 99.86% (conc. 0.3299 mg/L) was obtained at 3 h. 42 min., temperature of 35 °C, and adsorbent dosage of 0.1 g/50 mL. Using the Ag/Ti co-doped activated carbon, removal of phenol from pharmaceutical effluent followed pseudo-second order model, and fitted the Langmuir isotherm.

Fundamentals and Applications of Photo-Cross-Linking in Bioprinting.

This review provides a detailed overview of the rapidly advancing field of biofabrication, particularly with regards to the use of photo-cross-linking (i.e., light-based) techniques. The major emphasis of this review is on the fundamentals of photo-cross-linking and key criteria identified for the successful design and implementation of photo-cross-linked bioinks and bioresins in extrusion-based and lithography-based bioprinting. The general mechanisms associated with photo-cross-linking (e.g., free-radical chain polymerization, thiol-ene, photomediated redox) of natural and synthetic materials are described to inform bioink and bioresin design, which includes the selection of polymers, functional group modifications, photoinitiators, and light sources that enable facile and cytocompatible photo-cross-linking. Depending on material selection and the bioprinting technique of interest, we describe the specific bioink or bioresin properties and criteria that must be achieved to ensure optimal printability and utility. Finally, examples of current state-of-the-art applications of light-based bioprinting for in vitro tissue models, tissue engineering, and regenerative medicine are provided to further motivate future opportunities within the bioprinting landscape that are facilitated with light.

Functional‐Group Modification of Kraft Lignin for Enhanced Supercapacitors

The present efforts to improve the capacitances of Kraft lignin (KL) in supercapacitors have mainly focused on screening a KL substrate which could either compensate the poor conductivity of KL or directly contribute certain capacitance. While, enlarging the pseudocapacitance contributed by KL itself via hydroquinone/quinone redox cycles, remains a challenge due to roughly fixed content of hydroquinone species in natural KL. Herein we greatly improve such capacitance using a functionalized modification strategy in which methoxyls involved in KL are selectively transferred into phenolic hydroxyls which facilitate formation of additional hydroquinones and thus create higher pseudocapacitances. The oxidized KL materials own a maximum 25.6% enhancement of the phenolic hydroxyls in comparison to the raw KL, which results in 21.9% capacitance improvement from 322 to 390 F g -1 at 0.5 A g -1 in an acidic system.

Review of surface treatment methods for polyamide films for potential application as smart packaging materials: surface structure, antimicrobial and spectral properties

Abstract Background Antimicrobial packaging is currently one of the emerging technologies being pursued to extend the shelf-life of food products. Polyamides (PA) are widely used in food packaging, principally in laminate constructions, where they are used alone or combined with other materials. PA can be surface-treated using UV, plasma and corona treatments to create active film surfaces for various industrial applications. Scope and Approach the object of this article was to review different surface treatment methods for the potential manufacture of smart packaging materials including antimicrobial application in particular and to review the necessary spectral characteristics deemed necessary to achieve this. Key Findings and Conclusions XPS and AFM methods are useful tools in the identification of film surface analysis. For UV treatment, different light sources, including lasers, can be applied to create antimicrobially-active packaging materials. UV-treated PA films possess antimicrobial properties and offer potential for industrial and medical packaging applications, however, the application of such packaging materials to foods needs some special consideration. Different plasma treatment methodologies can be used for modification of PA surfaces, followed by attachment of antimicrobial coatings which are very limited in literature. Surface studies have shown that plasma-treated PA surfaces possess spectral properties similar to those for UV-treated samples. Corona treatment, like UV and plasma treatments, induce the modification of functional groups on PA film surfaces. Corona treatment has the capacity to activate polymeric surfaces for adhesion of a variety of functional coatings and should be explored further in terms of creating special antimicrobial coatings.

Molecular Tagging for the Molecular Characterization of Natural Organic Matter.

Natural organic matter (NOM) is the product of microbial and abiotic decay of plant and animal remains in terrestrial and aquatic ecosystems. On a molecular level, NOM is a complex mixture of organic molecules, of which the vast majority of structures are unknown. By identifying these molecules, our understanding of the many functions of NOM could be greatly enhanced. However, given that they are chromatographically inseparable and number in the thousands, traditional analytical techniques have proven unable to achieve this goal. A promising approach to enumerate functional groups and elucidate molecular structures within NOM is based on a combination of molecular tagging and high resolution spectroscopic techniques, such as nuclear magnetic resonance spectroscopy and mass spectrometry. Molecular tagging involves the selective modification of particular functional groups, inserting nuclei to act as reporters on their surrounding chemical environment. This allows examination of only the tagged molecules within NOM, thereby reducing the complexity of the mixture. In this review, the effectiveness of molecular tagging methods incorporating carbon, silicon, nitrogen, phosphorus, and deuterium into NOM are discussed. Some potential tagging methods which have not yet been applied to NOM are also presented.

Catalytic Lignin Depolymerization to Aromatic Chemicals.

In recent decades, research on lignin depolymerization and its downstream product transformation has drawn an enormous amount of attention from academia to industry worldwide, aiming at harvesting aromatic compounds from this abundant and renewable biomass resource. Although the lignin conversion can be traced back to the 1930s and various noncatalytic and catalytic methods have been explored to depolymerize lignin via direct lignin conversion research or lignin models conversion studies, the complexity of the lignin structure, various linkages, the high stability of lignin bonds, and the diverse fragments condensation process make lignin depolymerization to monomers a highly challenging task. For the potential practical utilization of lignin, compared with lignin conversion to liquid fuel with extra H2 consumption, maintaining the aromatic structure and preparing high-value aromatic chemicals from renewable lignin is more profitable. Therefore, lignin depolymerization to easy-to-handle aromatic monomers with acceptable conversion and selectivity is of great importance. In this article, we present our recent studies on lignin's catalytic conversion to aromatic chemicals. First, we introduce our research on protolignin depolymerization via a fragmentation-hydrogenolysis process in alcohol solvents. Then, focusing on the catalytic cleavage of lignin C-C and C-O bonds, we shed light on a recapitulative adjacent functional group modification (AFGM) strategy for the conversion of lignin models. AFGM strategy begins with the adjacent functional group modification of the target C-C or C-O bond to directly decrease the bond dissociation enthalpy (BDE) of targeted bonds or generate new substrate sites to introduce the cleavage reagent for further conversion. Subsequently, on the basis of these two concepts from AFGM, we summarize our strategies on lignin depolymerization, which highlight the effects of lignin structure, catalyst character, and reaction conditions on the efficiency of strategies. In short, the key point for lignin depolymerization to aromatics is promoting the lignin conversion and restraining the condensation. Compared with the complex research on direct lignin conversion, this bottom-up research approach, beginning with lignin model research, can make the conversion mechanism study clear and provide potential methods for the protolignin/technical lignin conversion. In addition, one of our perspectives for lignin utilization is that the products from lignin conversion can be used as monomers for artificial polymerization, such as the simple phenol (PhOH) and other potential acid compounds, or that lignin derivative molecules can be used to synthesize high-value synthetic building blocks.

Delonix regia heterogeneous catalyzed two-step biodiesel production from Pongamia pinnata oil using methanol and 2-propanol

The study described here was focussed on preparing heterogeneous catalysts (acid and base) by H2SO4 and KOH wet impregnation technique from raw Delonix regia pods after carbonization and steam activation, which was used in converting free fatty acids and glycerides in karanja oil into fuel-grade esters. Resistance to thermal degradation of the precursor material was evaluated by TGA analysis, while catalyst characterization was done through BET, EDAX, FT-IR, SEM and XRD. These helped in estimating efficient surface modification and efficient doping of functional groups. Optimization of both esterification and transesterification steps is done through L16 Taguchi matrices, with the following process parameters: agitation speed, alcohol to oil ratio, catalyst concentration, reaction duration, reaction temperature. With a maximum FFA conversion of 99.86%, the biodiesel yield was 99.39%. Fuel characterization tests and GC analyses for residual glycerides showed that the fuel has acceptable physico-chemical properties according to ASTM standards with low residual glycerides. Catalysts show significant reusability with sulfonated (H2SO4 impregnated) catalyst retaining efficiency up to 3 uses and base catalyst (KOH doped) up to 7 uses. A cost analysis of catalyst preparation shows that the indigenously developed catalysts reduce production costs by a significant margin, proving to be lucrative for commercialization.

Formation of boron – silica based mesoporous and studies of its adsorption ability for curcuminoids

The development aims of mesoporous silica formation in pharmaceutical fields were its uses as a drug delivery vehicle and in separation. It is possible because of the large particle surface area, the presence of pores, and the possibility to modify functional groups in the mesoporous materials. In this study, the formation of silica-based mesoporous and boron-silica-based mesoporous materials was carried out by sol-gel techniques and modification of functional groups was carried out by the co-condensation method. Mesoporous material characterization was carried out using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Fourier transform infrared (FTIR). Adsorption ability of curcuminoid onto the mesoporous was carried out through isotherm adsorption study approaches using adsorption models including Langmuir, Freundlich, and Temkin model. The results of the isotherm adsorption study showed that the Freundlich model is the best model for isotherm adsorption with an r2 value of 0.997.

One Pot Aqueous Synthesis of L-Histidine Amino Acid Capped Mn: ZnS Quantum Dots for Dopamine Sensing

Background: Mn doped ZnS is selected as the right element which is prominent among quantum dot for its high luminescent and quantum yield property and also non toxicity while comparing with other organometallic quantum dot synthesized by using different capping agents. Methods: An interesting observation based on colorimetric sensing of dopamine using manganese doped zinc sulfide quantum dot is discussed in this study. Mn doped ZnS quantum dot surface passivated with capping agents such as L-histidine and also in polymers like chitosan, PVA and PVP were studied and compared. The tunable fluorescence effect was also observed in different polymers and amino acid as capping agents. Optical characterization studies like UV-Visible spectroscopy and PL spectroscopy have been carried out. The functional group modification of Quantum dot has been analyzed using FTIR and size and shape analysis was conducted by using HRTEM image. Result: The strong and broad peak of FTIR in the range of 3500-3300 cm-1 confirms the presence of O-H bond. It is also observed that quenching phenomena in the luminescent peak are due to weaker confinement effect. The average size of the particle is shown to be around 4-5 nm. Changes in color of the quantum dot solution from transparent to dark brown has been due to the interaction with dopamine. Conclusion: Finally, L-Histidine amino acid capped Mn:ZnS shows better results in luminescence and size confinement properties. Hence, it was chosen for dopamine sensing due to its colloidal nature and inborn affinity towards dopamine, a neurotransmitter which is essential for early diagnosis of neural diseases

Food grade carboxymethyl cellulose preparation from African star apple seed (<i>Chrysophyllum albidum</i>) shells: optimization and characterization

α-cellulose isolated from African star apple seed shell (ASASS) was used as the raw material for the production of food-grade carboxymethyl cellulose (CMC). Preparation of CMC from ASASS cellulose was carried out by an etherification process, using sodium hydroxide and monochloroacetic acid (MCA) at various temperature. The cellulose and CMC were characterized by FTIR, XRD and SEM techniques. Degree of substitution (DS) was determined using potentiometric titration. Solubility increased with DS of CMC increased together with varied conditions but decreased at a certain level. The optimum results of varied conditions were 0.8015 DS for 30% NaOH concentrations; 0.6259 DS for 50℃ temperature and 0.9254 DS for the amount of MCA. The FTIR spectra revealed the functional group modification of native cellulose to CMC, with absorptions at 1409.49 cm-1 and 1640.05 cm-1 indicating ether and carboxyl functional group respectively. The results of XRD analysis showed that crystallinity of isolated cellulose decreased in the CMC and SEM showed the elongated long fibres in cellulose while the fibrils in CMC are short and rough. The obtained product is well suited for pharmaceutical and food additives.Keywords: Food grade, carboxymethyl cellulose, cellulose, optimization, degree of substitution, characterization.

Identification of putative Type-I sex pheromone biosynthesis-related genes expressed in the female pheromone gland of Streltzoviella insularis.

Species-specific sex pheromones play key roles in moth sexual communication. Although the general pathway of Type-I sex pheromone biosynthesis is well established, only a handful of genes encoding enzymes involved in this pathway have been characterized. Streltzoviella insularis is a destructive wood-boring pest of many street trees in China, and the female sex pheromone of this species comprises a blend of (Z)-3-tetradecenyl acetate, (E)-3-tetradecenyl acetate, and (Z)-5-dodecenyl acetate. This organism therefore provides an excellent model for research on the diversity of genes and molecular mechanisms involved in pheromone production. Herein, we assembled the pheromone gland transcriptome of S. insularis by next-generation sequencing and identified 74 genes encoding candidate key enzymes involved in the fatty acid biosynthesis, β-oxidation, and functional group modification. In addition, tissue expression patterns further showed that an acetyl-CoA carboxylase and two desaturases were highly expressed in the pheromone glands compared with the other tissues, indicating possible roles in S. insularis sex pheromone biosynthesis. Finally, we proposed putative S. insularis biosynthetic pathways for sex pheromone components and highlighted candidate genes. Our findings lay a solid foundation for understanding the molecular mechanisms underpinning S. insularis sex pheromone biosynthesis, and provide potential targets for disrupting chemical communication that could assist the development of novel pest control methods.

Quantitative Understanding of Charge-Transfer-Mediated Fe3+ Sensing and Fast Photoresponse by N-Doped Graphene Quantum Dots Decorated on Plasmonic Au Nanoparticles.

The formation of a heterostructure with plasmonic nanoparticles drastically alters the optoelectronic properties of graphene quantum dots (GQDs), resulting in exceptional properties. In the present work, we prepare nitrogen-doped GQDs decorated on gold nanoparticles (Au@N-GQDs) by a one-step green reduction method and study its extraordinary fluorescence and photoresponse characteristics. The as-prepared Au@N-GQDs show more than one order of magnitude enhancement in the fluorescence intensity as compared to the bare N-GQDs, which is attributed to hot electron generation and improved absorption in N-GQDs by local field enhancement and the modification of the edge functional groups. Because of the selective coordination to Fe3+ ions, the Au@N-GQDs exhibit extraordinary quenching of fluorescence, with ultrahigh sensitivity for the detection of Fe3+ (<1 nM). A new model for the charge-transfer dynamics is developed involving the Langmuir's law of adsorption to explain the unusual quenching, which strongly deviates from the known models of static/dynamic quenching. The proposed sensor is successfully implemented for the ultrasensitive detection of Fe3+ ions in human serum and Brahmaputra river water samples, representing its high potential applications in clinical as well as environmental diagnosis. Additionally, because of its high absorption in the UV-vis-NIR region and high charge density with long life excitons, the Au@N-GQDs are utilized as photodetectors with ∼104 times faster response than that of bare N-GQDs. The Au@N-GQD-based photodetector possesses a high responsivity of ∼1.36 A/W and a remarkably high external quantum efficiency of ∼292.2%, which is much superior to the GQD-based photodetectors reported till date. The underlying mechanism of ultrafast photoresponse is ascribed to the transfer of hot electrons along with the tunneling of the electrons from Au NPs to N-GQDs as well as the defect reduction of N-GQDs by the incorporation of Au NPs. Without the use of any charge transporting layer, the outstanding performance of N-GQD-based plasmonic photodetector opens up unique opportunities for future high-speed optoelectronic devices.

Hierarchical Porous Manganese- and Nitrogen-Codoped Carbon Nanosheets Derived from Surface Modified Biomass as Efficient Oxygen Reduction Catalysts for Al-Air Batteries

Oxygen reduction reaction (ORR) is essential for metal-air batteries and fuel cells, and it is urgent to develop non-precious metal catalysts with low cost and high performance for ORR. Here we propose a new general strategy for preparing hieratical porous manganese- and nitrogen-codoped carbon (Mn–N–C) derived from low cost biomass. This strategy demonstrates that pre-oxidation of the biomass with an optimized temperature plays an essential role in forming the unique structure of Mn–N–C due to the modification of surface functional groups on biomass. The resultant Mn–N–C displays superior ORR performance in both alkaline and neutral electrolytes, which is comparable or even higher than that of the commercial Pt/C catalyst. The superior electrocatalytic performance is ascribed to the intrinsically efficient Mn-Nx active sites and the high surface area together with the hieratical pores exposing more active sites, which is also confirmed by the density functional theory calculation. Furthermore, the Al-air battery based on the Mn–N–C cathode shows a high working voltage and maximum power density, demonstrating promising potential for practical application. This approach provides a new insight for low-cost and high performance electrocatalysts for metal-air batteries.

Seed Extract of Dypsis lutescens as Ecofriendly Corrosion Inhibitor for Mild Steel in Hydrochloric Acid Medium

The seed extract of Dypsis lutescens, had been analyzed for mild steel corrosion inhibition in acid medium with weight loss, thermodynamic, adsorption and electrochemical parameters. The results reflected that the extract is a potential corrosion inhibitor. IR spectra and SEM photographs recorded for functional group and surface modification analysis of mild steel, were agreeing with other parameters. Entire study revealed that the inhibitor works through adsorption of its molecules over the mild steel. From this study it is inferred that the seed extract of D. lutescens is an efficient, eco-friendly and alternate corrosion inhibitor for mild steel in acid medium.

Surface functional group modification induced partial Fermi level pinning and ohmic contact at borophene-MoS2 interfaces.

Large Schottky barrier at the electric contact interface drastically hinders the performance of two-dimensional (2D) semiconductor devices, because of which it is crucial to develop better methods to achieve the ohmic contact. Recently, a new field effect transistor (FET) device was constructed by the popular 2D channel material MoS2 and an electrode material borophene was detected theoretically, but the large Schottky barrier still existed. Hence, we used surface functional groups modification on the borophene surface to regulate this Schottky barrier, based on ab initio electronic structure calculations and quantum transport simulations. Our study shows that this method makes it possible to obtain tunable metal work functions in a wide range, and the ohmic contact can still be realized. Although van der Waals (vdW) contacts were observed at all the interfaces between the 2D borophene-based metals and the monolayer MoS2, the Fermi level pinning (FLP) effect was still obvious, and existed in our proposed system with the ohmic contact. Moreover, we also discuss the origin of the FLP with varying degrees. It was found that the interface dipole and metal-induced gap states (MIGS) would be responsible for the FLP of vertical and lateral directions, respectively. More precisely, we find that the size of MIGS is dependent on the relative orientation between the functional group and metal-MoS2 interface. This work not only suggests that surface functional group modification is effective in forming ohmic contact with MoS2, but also holds some implication in the fundamental research on metal-semiconductor contacts with the vdW type.