Performance and biocompatibility of OSTEMER 322 in cell-based microfluidic applicationsAubrecht, Petr; Smejkal, Jiří; Panuška, Petr; Španbauerová, Klára; Neubertová, Viktorie; Kaule, Pavel; Matoušek, Jindřich; Vinopal, Stanislav; Liegertová, Michaela; Štofik, Marcel; Malý, Jan
doi: 10.1039/d3ra05789epmid: 38268545
The Off-Stoichiometry Thiol–ene and Epoxy (OSTE+) polymer technology has been increasingly utilised in the field of microfluidics and lab-on-a-chip applications. However, the impact of OSTEMER polymers, specifically the OSTEMER 322 formulation, on cell viability has remained limited. In this work, we thoroughly explored the biocompatibility of this commercial OSTEMER formulation, along with various surface modifications, through a broad range of cell types, from fibroblasts to epithelial cells. We employed cell viability and confluence assays to evaluate the performance of the material and its modified variants in cell culturing. The properties of the pristine and modified OSTEMER were also investigated using surface characterization methods including contact angle, zeta potential, and X-ray photoelectron spectroscopy. Mass spectrometry analysis confirmed the absence of leaching constituents from OSTEMER, indicating its safety for cell-based applications. Our findings demonstrated that cell viability on OSTEMER surfaces is sufficient for typical cell culture experiments, suggesting OSTEMER 322 is a suitable material for a variety of cell-based assays in microfluidic devices.
Research progress on the catalytic and thermal decomposition of ammonium dinitramide (ADN)Tian, Yubo; Xu, Weibin; Cong, Weimin; Bi, Xueqian; He, Jiahui; Song, Zhe; Guan, Hongling; Huang, Chuande; Wang, Xiaodong
doi: 10.1039/d3ra08053fpmid: 38268549
Ammonium dinitramide (NH4N(NO3)2, ADN) is regarded as a promising oxidizer due to its low signature and high specific impulse. Generally, ADN undergoes exothermic decomposition above 140 °C accompanied by the byproduct of ammonium nitrate (AN). The inevitable endothermic decomposition of AN decreases the overall heat release, and so there is a need to develop efficient catalysts to guide ADN decomposition along desired pathways with a lower decomposition temperature and higher heat release. A suitable catalyst should be able to withstand the harsh conditions in a thruster to achieve a stable thrust force, which poses a huge obstacle for manufacturing a stable and active catalyst. This review gives a comprehensive summary of the thermal and catalytic decomposition pathways of ADN for the first time, which is expected to deepen the understanding of its reaction mechanism and provide useful guidance for designing prospective catalysts toward efficient ADN decomposition.
Rheological and radioactive decontamination properties of ethyl cellulose sols in green solvents at a temperature below 0 °CPan, Xunhai; Lin, Xiaoyan; Zhang, Hao; Liang, Lili; Pang, Chunxia; Gu, Kai; Hu, Yang; Xi, Hailing
doi: 10.1039/d3ra06641jpmid: 38268552
Strippable film decontamination has been considered one of the best prospects for radioactive surface decontamination due to its high decontamination effect and less secondary pollution. However, research into strippable films has until now focused on radioactive decontamination at room temperature. Therefore, it is vital to seek a suitable degradable material for preparing strippable films in removing contaminants in an extremely cold region, as it will face the problem of the freezing of the detergent. Ethyl cellulose (EC) is a kind of degradable biopolymer which is easily dissolved in volatile green organic solvents to form a sol below 0 °C which is advantageous for forming a film. Therefore, it would be the best choice for preparing a strippable film detergent. In this study, EC sols were obtained by placing EC powder into the green solvents anhydrous ethanol and ethyl acetate. The steady and dynamic rheological behavior of EC sols was investigated with a rotary rheometer with the temperature ranging from −10 °C to 0 °C to disclose their spraying performance. Moreover, the radioactive decontamination effect of EC sols and the mechanism were also investigated. The results showed that the EC sols were pseudoplastic fluids which obeyed the Ostwald–de Waele power law below 0 °C. Furthermore, the viscosity of EC sols could be reduced by stirring, which is convenient for large-area spraying during decontamination below 0 °C. At −10 °C, the comprehensive decontamination rates of all plates were over 85%. Therefore, EC sols could be used as a basic material for strippable film decontamination below 0 °C.
Resonant Raman scattering on graphene: SERS and gap-mode TERSKurus, N. N.; Kalinin, V.; Nebogatikova, N. A.; Milekhin, I. A.; Antonova, I. V.; Rodyakina, E. E.; Milekhin, A. G.; Latyshev, A. V.; Zahn, D. R. T.
doi: 10.1039/d3ra07018bpmid: 38268550
Nanoscale deformations and corrugations occur in graphene-like two-dimensional materials during their incorporation into hybrid structures and real devices, such as sensors based on surface-enhanced Raman scattering (SERS-based sensors). The structural features mentioned above are known to affect the electronic properties of graphene, thus highly sensitive and high-resolution techniques are required to reveal and characterize arising local defects, mechanical deformations, and phase transformations. In this study, we demonstrate that gap-mode tip-enhanced Raman Scattering (gm-TERS), which offers the benefits of structural and chemical analytical methods, allows variations in the structure and mechanical state of a two-dimensional material to be probed with nanoscale spatial resolution. In this work, we demonstrate locally enhanced gm-TERS on a monolayer graphene film placed on a plasmonic substrate with specific diameter gold nanodisks. SERS measurements are employed to determine the optimal disk diameter and excitation wavelength for further realization of gm-TERS. A significant local plasmonic enhancement of the main vibrational modes in graphene by a factor of 100 and a high spatial resolution of 10 nm are achieved in the gm-TERS experiment, making gm-TERS chemical mapping possible. By analyzing the gm-TERS spectra of the graphene film in the local area of a nanodisk, the local tensile mechanical strain in graphene was detected, resulting in a split of the G mode into two components, G+ and G−. Using the frequency split in the positions of G+ and G− modes in the TERS spectra, the stress was estimated to be up to 1.5%. The results demonstrate that gap-mode TERS mapping allows rapid and precise characterization of local structural defects in two-dimensional materials on the nanoscale.
The use of banana peel as a low-cost adsorption material for removing hexavalent chromium from tannery wastewater: optimization, kinetic and isotherm study, and regeneration aspectsAmeha, Bereket; Nadew, Talbachew Tadesse; Tedla, Tsegaye Sissay; Getye, Belay; Mengie, Destaw Agumass; Ayalneh, Shiferaw
doi: 10.1039/d3ra07476epmid: 38268547
When the concentration of hexavalent chromium (Cr(vi)) in the environment is greater than a certain limit, it becomes a global concern. Thus, the aim of this study was to use banana peel as an adsorbent to remove heavy metals, specifically Cr(vi) ions from wastewater. Banana peel (BP) was activated in a furnace for 2 h (h) at 450 °C and 50% humidity. Subsequently, the activated BP was characterized by proximate analysis, elemental analysis, scanning-electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Brunauer Emmett Teller (BET) analysis, and thermogravimetric analysis (TGA). According to the characterization results, the activated BP possessed a porous surface and high surface area of 200 m2 g−1, which are important adsorption parameters. Additionally, the removal efficiency for Cr(vi) was evaluated in terms of pH, contact time, initial concentration, and adsorbent dose. Consequently, the optimal operating conditions for removing 94% of Cr(vi) were found to be an adsorption time of 92 min, adsorbent dose of 1.5 g L−1, pH of 3, and initial Cr(vi) concentration of 38 mg L−1. In addition, the adsorption kinetics and isotherms were examined. The pseudo-first-order model with an R2 of 0.996 and the Langmuir isotherm with an R2 of 0.997 were found to be the most effective mathematical representations of the rate and nature of Cr(vi) adsorption on the surface of the activated BP, respectively. Furthermore, it was discovered that the activated BP could be reused six times before its removal efficiency was reduced to less than 70%.
Evaluation of sustained drug release performance and osteoinduction of magnetron-sputtered tantalum-coated titanium dioxide nanotubesZhan, Jing; Li, Li; Yao, Lili; Cao, Zheng; Lou, Weiwei; Zhang, Jianying; Liu, Jinsong; Yao, Litao
doi: 10.1039/d3ra08769gpmid: 38268551
Modifying the drug-release capacity of titanium implants is essential for maintaining their long-term functioning. Titanium dioxide nanotube (TNT) arrays, owing to their drug release capacity, are commonly used in the biomaterial sphere. Their unique half open structure and arrangement in rows increase the drug release capacity. However, their rapid drug release ability not only reduces drug efficiency but also produces excessive local and systemic deposition of antibiotics. In this study, we designed a tantalum-coated TNT system for drug-release optimization. A decreased nanotube size caused by the tantalum nanocoating was observed through SEM and analyzed (TNT: 110 nm, TNT-Ta1: 80 nm, TNT-Ta3: 40 nm, TNT-Ta5: 20 nm, TNT-Ta7: <5 nm). XPS analysis revealed the distribution of the chemical components, especially that of the tantalum element. In vitro experiments showed that the tantalum nanocoating enhanced cell proliferation; in particular, TNT-Ta5 possessed the best cell viability (about 1.18 of TNT groups at 7d). It also showed that the tantalum nanocoating had a positive effect on osteogenesis (especially TNT-Ta5 and TNT-Ta7). Additionally, hydrophilic/hydrophobic drug (vancomycin/raloxifene) release results indicated that the TNT-Ta5 group possessed the most desirable sustained release capacity. Moreover, in this drug release system, the hydrophobic drug showed more sustained release capacity than the hydrophilic drug (vancomycin: sustained release for more than 48 h, raloxifene: sustained release for more than 168 h). More importantly, TNT-Ta5 is proved to be an appropriate drug release system, which possesses cytocompatibility, osteogenic capacity, and sustained drug release capacity.
New insights on the optical properties and upconversion fluorescence of Er-doped CoAl2O4 nanocrystalsKien, N. T.; Lam, V. D.; Duong, P. V.; Hien, N. T.; Luyen, N. T.; Do, P. V.; Binh, N. T.; Ca, N. X.
doi: 10.1039/d3ra07928gpmid: 38268546
In this study, Er-doped CoAl2O4 nanocrystals (NCs) were synthesized via co-precipitation. All the NCs were crystallized in the form of a single phase with a spinel structure and Er3+ ions replaced Al3+ ions in the formation of the CoAl2−xErxO4 alloy structure. The optical characteristics of the Er3+ ion-doped CoAl2O4 NCs were thoroughly investigated by analyzing both the UV-VIS and photoluminescence spectra, using the Judd–Ofelt theory. The effect of Er doping content on the luminescent properties of the CoAl2O4 pigment (using lasers emitting at wavelengths of 413 and 978 nm) has been studied. The values of Judd–Oflet intensity parameters (Ω2, Ω4, and Ω6) were determined from the absorption spectra using the least square fitting method. The J–O parameters were calculated and compared with those of other host materials; the values of the Ω2, Ω4, and Ω6 parameters decreased with an increase in Er concentration. This suggests that the rigidity and local symmetry of the host materials become weaker as the concentration of Er3+ ions increases. The highest value of the Ω2 parameter, when compared with Ω4 and Ω6, suggests that the vibrational frequencies in the given samples are relatively low. The upconversion fluorescence phenomenon was observed and explained in detail under an excitation wavelength of 978 nm when the excitation power was varied.
Cross aldol OPAL bioconjugation outcompetes intramolecular hemiaminal cyclisation of proline adjacent N-terminal α-oxo aldehydes at acidic pHTufail, Afzaal; Akkad, Saeed; Hatton, Natasha E.; Yates, Nicholas D. J.; Spears, Richard J.; Keenan, Tessa; Parkin, Alison; Signoret, Nathalie; Fascione, Martin A.
doi: 10.1039/d3ra08776jpmid: 38268544
Novel methods to construct small molecule–protein bioconjugates are integral to the development of new biomedicines for a variety of diseases. C–C linked bioconjugates are increasingly desirable in this application due to their in vivo stability and can be accessed through cross aldol bioconjugation of reactive α-oxo aldehyde handles easily introduced at the N-terminus of proteins by periodate oxidation. We previously developed an organocatalyst-mediated protein aldol ligation (OPAL) for chemical modification of these reactive aldehydes, but the efficiency of this method was limited when a proline residue was directly adjacent to the N-terminus due to intramolecular hemiaminal formation. Herein we explore the competition between this cyclisation and the OPAL modification and demonstrate bioconjugation can be favoured through use of acidic pH for both oxidation and OPAL, and optimisation of reaction conditions and organocatalyst. We then showcase the utility of this acidic-OPAL in modification of the cholera toxin B-subunit (CTB), a homo-pentameric protein of biomedical promise.