Bacterial adhesion to biomaterials/tissues can lead to inevitable infection, inflammation, and even death, posing a serious threat to human health. An in-depth understanding of interactions between bacteria and biomaterial surfaces could provide effective strategies for inhibiting bacterial adhesion. Adhesion behavior can be quantified using adhesion forces measured by atomic force microscopy (AFM)-based force spectroscopy. Although AFM-based force spectroscopy has been applied to investigate bacterial adhesion, the effect of biomaterials (including metals, ceramics, polymers, and cells) and surface modifications (including patterning and coating) on bacterial adhesion forces has not been systematically summarized. Therefore, this review provides a comprehensive overview of recent developments in bacterial adhesion on biomaterials, focusing on the use of AFM-based force spectroscopy with bacterial probes. Surface topography on metals and ceramics reduces the contact area and inhibits bacterial adhesion. Coatings and chemical modifications on ceramic surfaces can either inhibit or promote bacterial adhesion, depending on the surface properties. The discussion about the bacterial adhesion on different biomaterial surfaces would benefit the inhibition of adhesion and the rational surface design for enhanced antibacterial properties. Statement of Significance The growing threat of antimicrobial resistance has led to increased interest in developing antibacterial materials with tailored surface properties. A critical aspect of understanding bacterial adhesion on surfaces is quantifying bacterial adhesion forces, often using atomic force microscopy (AFM)-based force spectroscopy. While numerous studies have explored how biomaterials and surface modifications influence bacterial adhesion, a systematic review focusing on the nanomechanical aspects of adhesion forces is lacking. Here, a broad overview of the state-of-the-art research addresses this gap by summarizing the influence of biomaterials and surface modifications on bacterial adhesion forces in the context of AFM-based force spectroscopy. It will be of interest to researchers designing more effective antimicrobial materials and surfaces.

Bacterial adhesion is a critical process in many fields, such as implant infections, microbiologically influenced corrosion and bioelectricity generation in microbial fuel cells. During bacterial adhesion, the contact area between the attached bacteria and the patterned surface plays an important role. In this study, different surface topographies and treatments were employed to simulate three circumstances with different contact areas. A nanostripe structure with a period of 576.9 nm and a height of 203.5 nm was fabricated on pure titanium by femtosecond laser ablation. Bacteria in liquid attached to the peaks of the nanostripe structure and were stretched on the two adjacent nanostripes. Compared with the polished surface, the contact area between bacteria and the nanostripe surface was reduced to 50%, resulting in a reduction (about 50%) in the coverage rate of attached bacteria. In addition, the nanostripe surface was a hydrophobic surface with a water contact angle (WCA) of 112.1°, and the surface potential of the nanostripe surface was higher than that of the polished surface. However, the surface potential and wettability of the nanostripe surface played a minor role in the bacterial adhesion due to the reduced contact area. Upon drying, the attached bacteria on the nanostripe surface sank into the valley region and the contact area was about 40% larger than that on the polished surface. The lateral strength of bacterial adhesion on nanostripe surfaces was higher than that on polished surfaces, due to the larger contact area. Upon applying a lateral force of 10.0 nN, the percentage of bacteria remaining on the nanostripe surface (31.1%) was higher than that on the polished surface (11.9%). Hence, the bacterial adhesion on the nanopatterned surface was mainly determined by the contact area. The in-depth exploration of the relation between bacterial adhesion on the nanopatterned surface and the contact area enables the rational surface designs of biomaterials to regulate bacterial adhesion.

Groundwater serving as a drinking water resource usually contains manganese ions (Mn2+) that exceed drinking standards. Based on the Mn biogeochemical cycle at the hydrosphere scale, bioprocesses consisting of aeration, biofiltration, and disinfection are well known as a cost-effective and environmentally friendly ecotechnology for removing Mn2+. The design of aeration and biofiltration units, which are critical components, is significantly influenced by coexisting iron and ammonia in groundwater; however, there is no unified standard for optimizing bioprocess operation. In addition to the groundwater purification, it was also found that manganese-oxidizing bacteria (MnOB)-derived biogenic Mn oxides (bioMnOx), a by-product, have a low crystallinity and a relatively high specific surface area; the MnOB supplied with Mn2+ can be developed for contaminated water remediation. As a result, according to previous studies, this paper summarized and provided operational suggestions for the removal of Mn2+ from groundwater. This review also anticipated challenges and future concerns, as well as opportunities for bioMnOx applications. These could improve our understanding of the MnOB group and its practical applications.

Bacterial adhesion and biofilm formation impose a heavy burden on the medical system. Bacterial adhesion on implant materials would induce inflammation and result in implant failure. The adhesion of bacteria on food-processing and handling equipment may lead to food-borne illness. To reduce and even prevent bacterial adhesion, some bacterial anti-adhesion surface designs have been developed. However, the effect of some surface properties (including surface patterning, roughness and wettability) on bacterial adhesion has not been systematically summarized. In this review, a comprehensive overview of bacterial anti-adhesion surface design is presented. Modifying the surface pattern and roughness could reduce the contact area between bacteria and surfaces to weaken the initial adhesion force. Fabricating superhydrophobic surface or modifying hydrophilic functional groups could hinder the bacterial adhesion. The analysis and discussion about influencing factors of bacterial anti-adhesion surfaces provide basic guidelines on antibacterial surface design for future researches.

Bacterial infections on implants cause an inflammatory response and even implant failure. Bacterial adhesion is an initial and critical step during implant infection. The prevention of bacterial adhesion to implant materials has attracted much attention, especially for biodegradable metals. A deep understanding of the mechanisms of bacterial adhesion to biodegradable metals is urgently needed. In this work, a bacterial probe based on atomic force spectroscopy was employed to determine the bacterial adhesion to Zn alloy, which depended on surface charge, roughness, and wettability. Negative surface charges of Zn, Zn-0.5Li, and 316L generated electrostatic repulsion force towards bacteria. The surface roughness of Zn-0.5Li was significantly increased by localized corrosion. Bacterial adhesion forces on Zn, Zn-0.5Li, and 316L were 325.2 pN, 519.1 pN, and 727.7 pN, respectively. The density of attached bacteria (early-stage bacterial adhesion) on these samples exhibited a positive correlation with the bacterial adhesion force. The bacterial adhesion force and adhesion work provide a quantitative determination of the interactions between bacteria and biodegradable alloys. These results provide a deeper understanding of early bacterial adhesion on Zn alloys, which can further guide the antibacterial surface design of biodegradable materials for clinical application.

Protein could adsorb on the surfaces when biomedical metals contact with body fluids and then affect the corrosion behavior of metals. In vitro results demonstrate that protein adsorption retards metal dissolution, while the detachment of metal-protein complex from the surface accelerates the corrosion or its deposition could impede the metal corrosion. Protein adsorption and its influences on the metal corrosion are related to many factors, such as the type and content of proteins as well as the property of metals. Therefore, consensus has not been made on the influences of protein on metal corrosion. However, as one of most important components in the body fluids, it should be taken into consideration for the effects of protein on the corrosion behavior of metals in vitro. So that we can find the discrepancy between in vivo and in vitro tests and find the suitable simulated environment in vitro. This will help predict reasonably the corrosion behavior of biomedical metals in the human body.

Localized corrosion makes Zn vulnerable to unpredictable fracture under stress loading, resulting in mechanical failure when used as implants in human body. This study reveals that 0.8 wt.% Li alloying suppresses pitting corrosion of Zn significantly in simulated body fluid, resulting in 290 times less of localized corrosion volume after immersion for 30 days. A corrosion layer with two sub-layers forms on the alloy surface. The 10-nm-thick inner layer consists of amorphous Li2O/LiOH and ZnO/Zn(OH)(2), while the 55-nm-thick outer sub-layer consists of Li2CO3 polycrystals, which is very effective to suppress pitting corrosion by blocking chloride ion penetration.

Self-healing hydrogel systems usually suffer from poor mechanical performance stemmed from weaker and reversible non-covalent interactions or dynamic chemical bonds, which hamper their practical applications. This issue is addressed by adopting a double-crosslinking design involving both dynamic Schiff base bonds and non-dynamic photo-induced crosslinking. This leads to the formation of a special topological structure which simultaneously provide good self-healing capability and enhanced mechanical performance (elastic recovery and tensile modulus of 157.4 kPa, close to modulus of native skin). The quaternary ammonium and protonated amino groups can provide superior antibacterial capability; and Schiff base formation between residual aldehyde groups and amino groups on tissue surface contribute to hydrogel's adhesion to tissues (5.9 kPa). Furthermore, the multifunctional hydrogels with desirable mechanical performance, self-healing capability, superior antibacterial capability and tissue adhesion can significantly promote healing of infectious cutaneous wound, tissue remodeling and regeneration.

Fluorescent carbon nanodots (CNDs) have exhibited attractive potential for biomedical applications due to their intriguing luminescent properties and good biocompatibility. One interesting property of CNDs is that they typically show different emission colors upon optical excitation using different wavelengths. However, it is still a challenge to obtain emissions covering the entire visible spectrum with comparable intensity with only one type of CND. Herein, CNDs with tunable full-color luminescence are successful prepared by a solvothermal approach, show broad absorption (200-700 nm) and fluorescence emission (nearly cover the entire visible region: from 400 to 700 nm) with comparable fluorescence intensities. The oxidation (o-CNDs) and reduction (r-CNDs) of CNDs surface would lead to the shifting of photoluminescence band into blue/green and red-light region, respectively. Further spectroscopic analyses and structural characterizations of CNDs (pristine state), o-CNDs (oxidation state) and r-CNDs (reduction state) demonstrate that O-related defect states (C=O) and N-related defect states (C=N) on surface of CNDs should be responsible for blue/green and red fluorescence emissions, respectively. Moreover, the CNDs are found to be biocompatible, as verified by in vitro cells assay and in vivo histological analysis. In vivo fluorescence imaging assay demonstrates that CNDs can be excreted through intestine and bladder system. The tunable full-color emission, good biocompatibility and metabolism suggest that the CNDs are promising fluorescent probes for biomedical applications. (C) 2020 Elsevier Ltd. All rights reserved.

Most photocrosslinkable hydrogels have inadequacy in either mechanical performance or biodegradability. This issue is addressed by adopting a novel hydrogel design by introducing two different chitosan chains (catechol-modified methacryloyl chitosan, CMC; methacryloyl chitosan, MC) via the simultaneous crosslinking of carbon-carbon double bonds and catechol-Fe3+ chelation. This leads to an interpenetrating network of two chitosan chains with high crosslinking-network density, which enhances mechanical performance including high compressive modulus and high ductility. The chitosan polymers not only endow the hydrogels with good biodegradability and biocompatibility, they also offer intrinsic antibacterial capability. The quinone groups formed by Fe3+ oxidation and protonated amino groups of chitosan polymer further enhance antibacterial property of the hydrogels. Serving as one of the two types of crosslinking mechanisms, the catechol-Fe3+ chelation can covalently link with amino, thiol, and imidazole groups, which substantially enhance the hydrogel's adhesion to biological tissues. The hydrogel's adhesion to porcine skin shows a lap shear strength of 18.1 kPa, which is 6-time that of the clinically established Fibrin Glue's adhesion. The hydrogel also has a good hemostatic performance due to the superior tissue adhesion as demonstrated with a hemorrhaging liver model. Furthermore, the hydrogel can remarkably promote healing of bacteria-infected wound.

An integrated and effective method to realize simultaneous desulfurization and denitrification by the Spray Dryer Absorption (SDA) method combined with the NaClO2 was carried out in this paper. The optimum conditions on desulfurization were verified, as well as the cooperative effect and removal mechanism between SO2 and NO was speculated. The results showed that the best desulphurization efficiency was obtained when NaOH was added into the slurry with a liquid-solid ratio of 6:1. At the same time, the stirring speed was 250 r/min and the rotational speed of the atomizer was 250 r/s. In addition, NaClO2 was selected as the liquid oxidizer to remove NO, and the efficiencies ranged from 65% to 90% with different concentration. When the flue gas temperature was 70 degrees C, the denitrification efficiency was the best. The concentration of NaClO2 was 1.5%, and the slurry stirring speed and atomizer speed was 250 r/min and 300 r/s, respectively. When SO2 and NO coexisted in the flue gas, not only did SO2 removal efficiency remain high, but NO removal efficiency also exceeded 80%. Obviously, SO2 had an obvious positive effect on the removal of NO, and the related mechanisms as well as some theories were studied in this research.

BACKGROUND A novel semi-dry method called SDA (spray drying absorption) for the simultaneous removal of mercury (Hg-0) and sulfur dioxide (SO2) have been proposed in this article, in which Hg-0 was initially oxidized by gaseous oxidant (O-3) and liquid oxidant (K2S2O8, H2O2, and NaClO2), after which SO2 and Hg2+ were absorbed by Ca(OH)(2). RESULTS The effects on different process conditions and additives on Hg-0 removal were explored at first, and the results indicated that the Hg removal efficiency could be improved by oxidizing or extending the residence time of the liquid phase reaction. When SO2 and Hg coexist in the atmosphere, additives including oxidants or composite additives were added into the mixed system, and the results indicated that the best removal efficiency of SO2 and Hg was about 99.5% and 51% respectively. CONCLUSION Since SO2 has good water solubility, it would affect the oxidation of Hg and the removal of Hg. When there was nitric oxide (NO) in the atmosphere, a new stable product was generated which contributed to the removal of Hg, and the removal efficiency of SO2 and Hg was about 99.5% and 57% respectively. (c) 2020 Society of Chemical Industry

BACKGROUND In order to improve the desulfurization and denitrification performance of Al2O3@TiO2-Ce adsorbent, ultrasound-assisted surface modification using different pore-forming agents (CTAB (Cetyl Trimethyl Ammonium Bromide), NH4NO3, and Urea) was introduced into the preparation process of Al2O3@TiO2-Ce core-shell structure adsorbent. RESULTS Among the adsorbent modified by various pore-forming agent, CTAB modified Al2O3@TiO2-Ce adsorbent showed the best denitrification efficiency, and the ultrasound-assisted modification of CTAB had a positive effect on the removal efficiency of SO2 and NOx. The adsorption performance increased with the increase of addition amount of CTAB in the range of 5% to 10% but decreased with the increase of CTAB addition amount in the range of 10% to 20%. Petal-like wrinkles appeared on the surface of CTAB modified adsorbent, and the distribution of the pores on the surface was dispersed uniformly by ultrasound. CONCLUSION The petal-like wrinkle could effectively increase the specific surface area and pore volume of the adsorbent, and pore size distribution was more evenly, which was considered to be the key to improve the adsorption performance. The SO2 and NOx adsorption followed the pseudo-first order rate expression, and the adsorption process was limited by both external diffusion and intraparticle diffusion. This work provides an experimental and theoretical basis for the surface modification of simultaneous desulfurization and denitrification adsorbents. (c) 2020 Society of Chemical Industry

Over the years, the combined Non-thermal Plasma (NTP) denitrification process which is used for decomposition of NOx has have become an application technology with great potential. And the formation of byproducts, such as N 2 O and O 3 , which is an important factor that interfere with NO removal efficiency, has a high research value. In present study, HZSM-5 molecular sieve was selected as the packed material in dielectric barrier discharge reactor to investigate the effect of reaction conditions, such as with/without packed bed, discharge power, inner electrode diameter, electrode shape and operation time, on formation and conversion characteristics of byproducts (N 2 O and O 3 ). Results showed that the presence of HZSM-5 pellets in discharge zone increases the discharge power, NO removal efficiency and the concentration of the byproducts in the outlet. The optimization of electrode diameter and the utilization of screw thread electrode increased the NO removal efficiency and the yield of N 2 O and O 3 . The pellets temperature increases with the operation time and the enhancement of input energy, which has different effects on O 3 and N 2 O. These results provide some new methods for improving the NTP-assisted catalytic denitrification process.

In this work, a series of Mn-Co rod-like layered catalysts self-assembled from porous rod aggregates were fabricated by a simple solvothermal approach. Compared with Mn-Co particles, Mn-Co rods exhibited a much better SCR performance (achieving >93% NOx conversion at 75 degrees C) and high N-2 selectivity. The outstanding catalytic performance was mainly attributed to the large specific surface area and unique rod-like mesoporous structures, which could provide more active sites and reaction centers for the reaction gas to further promote the de-NOx performance of the catalyst. In addition, the high atomic ratio of Mn4+/Mn on the catalyst surface, strong acid strength, and large acidity amount also had positive effects on its catalytic activity. Moreover, Mn-Co rods possessed a better catalytic cycle performance and more surface acid sites due to the synergistic effect between Co and Mn species.

BACKGROUND The combined Adsorption-Nonthermal Plasma Catalytic process (A-NTP-C) which is used for decomposition of NOx has become a technical approach of high research value.Many studies have shown that the better the adsorption performance of the catalyst in the A-NTP-C process, the higher the conversion of NO. The type of Cu precursors will affect the chemical/physical properties of Cu-based catalysts, thus influencing the adsorption performance of catalysts. In this study, an ion exchange process was used to prepare Cu/ZSM-5 catalysts with three Cu precursors, namely copper acetate (AC-Cu), copper nitrate (N-Cu) and copper sulfate (S-Cu). Results Different Cu precursors led to differences in Cu ion exchange capacity of Cu/ZSM-5; the Cu content of AC-Cu/ZSM-5 was the highest. Furthermore, even with the same Cu content as N-Cu/ZSM-5 and S-Cu/ZSM-5, the AC-Cu/ZSM-5 catalyst showed the best adsorption performance. Conclusion X-ray photoelectron spectroscopy results indicated that CuO and isolated tetrahedron-coordinating Cu(II) were the main forms of Cu species on Cu/ZSM-5. The results of in situ DRIFTs indicated that NO was oxidized by CuO and the generated NO2 was adsorbed by H+ and isolated Cu (II). The AC-Cu/ZSM-5 catalysts had the largest amount of tetrahedron-coordinating isolated Cu (II) and the strongest H+ electrophilic ability, giving it the best NOx adsorption performance. The different precursors had little effect on the ZSM-5 structure, but did cause differences in pore volume, which might influence the adsorption capacity of NOx to some extent. These conclusions provide new ideas and methods for optimizing the adsorption capacity of Cu/ZSM-5. (c) 2019 Society of Chemical Industry (c) 2019 Society of Chemical Industry

Magnesium oxide (MgO) with different morphologies was prepared by oxalic acid sol-gel method and the MgO were used to prepare three different kinds of adsorbents for simultaneous SO2 and NOx removal from coal-fired flue gas. It was found that the core-shell coated adsorption material MgO@CeO2-MnOx prepared from MgO formed by calcination of magnesium oxalate at 650. had the best performance. The MgO@CeO2-MnOx exhibited an adsorption breakthrough time up to 50 min and dynamic adsorption capacity of 0.3507 mmol/g and 0.1407 mmol/g for SO2 and NOx respectively. This is better than any other composite material. The N-2 adsorption-desorption isotherms result showed that core-shell structure material possessed the largest specific surface area, which could be its basic advantage for efficient adsorption. According to different operating conditions tests, it was found that the adsorption of SO2 and NOx by the adsorbent was dominated by chemisorption. Therefore, the surface metal material (MnOx, CeO2) played an important role in the adsorption process. According to FTIR and DRIFTS analysis, it was observed that the SO2 and NO were oxidized by hydroxyl groups on the absorbent surface and the oxidation was further aggravated by the presence of Mn4+, Mn3+, Ce3+ and Ce4+. Core-shell materials successfully prepared can reduce or weaken the adsorption competition between SO2 and NOx in three aspects: 1. The surface oxidation ability is strengthened and it is easy to adsorb the two substances, which makes the metal oxides on the shell surface interact fully with the adsorbents; 2. More and more effective adsorption sites are provided; 3. The adsorbent provides greater specific surface area and appropriate pore size.

The Al2O3@TiO2 core-shell structure adsorbent was designed, prepared, and used to reduce the competitive adsorption between SO2 and NO. The result showed that gamma-Al2O3 and anatase were obtained in this study, and Al2O3 was well wrapped by TiO2 to form the core-shell structure. The Al2O3@TiO2 core-shell structure adsorbent with the core-shell mole ratio of 1: 1 showed the best capacity of simultaneous desulfurization and denitrification, and the capacity was much better than Al2O3, Al2O3 + TiO2, and TiO2. NOx is easier to get though the pore of the shell material because of the smaller molecular diameter of NOx comparing with SO2, and the special structure of the core-shell adsorbent can be used to change the partial pressure of NOx and SO2 on the surface of the core material, thereby reducing the competitive adsorption. NO and SO2 would be catalytically oxidized to NO2 and SO3 on the shell structure, then SO3 was adsorbed by the shell material, and NOx was adsorbed by the core. Al-O and Ti-O were the adsorption sites, and the product of chemisorption was nitrate and sulfate radical.

A series of transition binary metal oxides were derived from Mg-Al, Ni-Al and Co-Al hydrotalcite-like compounds (HTLCs) with the intervention of ultrasound during the crystallization process, and the toluene removal rate of the hydrotalcite-derived oxides (HTOs) was investigated. The results of the toluene oxidation test showed that the conversion efficiency of ultrasonic intervened samples was higher than those of untreated samples. Focus solely on the elements difference, the conversion efficiency of CoAl-HTO is the highest among all samples, followed by NiAl-HTO, and MgAl-HTO is the lowest for both ultrasonic-treated and untreated samples. However, the conversion efficiency of ultrasonic treated NiAl-HTO (T-90=275 degrees C) is higher than that of untreated CoAl-HTO (T-90=300 degrees C) but still lower than that of treated CoAl-HTO (T-90=270 degrees C), inferred the positive influence of the ultrasonic intervention to the HTOs on toluene degradation. The properties of those samples were characterized by XRD, XPS, SEM, H-2-TPR and physisorption equipment. The characterization results showed that the better toluene degradation ability might be attributed to the more reactive Co2+ and abundant oxygen vacancies exposed on the sample's surface which revealed by the ultrasonic intervention, as well as the large surface area and the high Oads/Olatt. This work provided novel evidence for the influence of ultrasonic intervention on the material surface modification and toluene degradation which corresponding to the Mars-van Krevelen mechanism.

Using glucose and polyvinylpyrrolidone as raw materials, MgO-organic component materials were prepared by a one-step hydrothermal method. The material is used to improve the efficiency of simultaneous removal of SO2 and NOx, and to reduce the competitive adsorption of both. In the experiments, the adsorption of SO2 and NOx in simulated coal-fired flue gas was tested with MgO-organic component/pure MgO/MgO (PVP modified)/MgO (glucose modified), and the test results were compared. It is very noteworthy that the SO2 dynamic adsorption capacity of the MgO-organic component (the glucose/polyvinylpyrrolidone ratio is 1:3) was 0.3627 mmol/g; while that of NOx was 0.2176 mmol/g, and the adsorption breakthrough time (time taken when the NOx removal rate was 50%) was as long as 60 min (the total flow rate of simulated flue gas is 200 ml/min, the space velocity is 24000 h(-1), the reaction temperature is 100 degrees C, the concentration of SO2 and NOx is 500 ppm and 300 ppm, respectively). In this study, the organic component enhances the simultaneous desulfurization and denitration performance of MgO from three aspects and is verified by different characterization tests. There are an increase in specific surface area, an increase in surface energy and the insert of active functional groups. In particular, the insert of C=O can greatly improve the adsorption efficiency of NOx. Meanwhile, the adsorption process under different operating conditions is discussed in order to provide theoretical support for industrial practice. The work presented here has profound implications for future studies of simultaneous desulfurization and denitration field. Moreover, the economy and sustainability of the technology meet the basic requirements of waste reduction in cleaner production. (C) 2019 Published by Elsevier Ltd.