Synergistic Adsorption and In Situ Catalytic Conversion of SO2 by Transformed Bimetal-Phenolic Functionalized Biomass.

SO2 removal is critical to flue gas purification. However, based on performance and cost, materials under development are hardly adequate substitutes for active carbon-based materials. Here, we engineered biomass-derived nanostructured carbon nanofibers integrated with highly dispersed bimetallic Ti/CoOx nanoparticles through the thermal transition of metal-phenolic functionalized industrial leather wastes for synergistic SO2 adsorption and in situ catalytic conversion. The generation of surface-SO32- and peroxide species (O22-) by Ti/CoOx achieved catalytic conversion of adsorbed SO2 into value-added liquid H2SO4, which can be discharged from porous nanofibers. This approach can also avoid the accumulation of the adsorbed SO2, thereby achieving high desulfurization activity and a long operating life over 6000 min, preceding current state-of-the-art active carbon-based desulfurization materials. Combined with the techno-economic and carbon footprint analysis from 36 areas in China, we demonstrated an economically viable and scalable solution for real-world SO2 removal on the industrial scale.

Potassium assisted pyrolysis of Chinese Baijiu distillers' grains to prepare biochar as controlled-release K fertilizer.

A novel K-loaded biochar as controlled-release K fertilizer was prepared through K assisted pyrolysis of distillers' grains (DGs, typical solid-byproducts of Chinese Baijiu) under different atmospheres (N2 and CO2) and temperatures (400 and 800 °C). The fabricated DGs-based biochar exhibited high K loading (200.20-232.33 mg/g), and the release kinetics and column leaching experiments suggested that K-loaded biochar exhibited excellent controlled release performance in a long term. Compared with other biochar, the K-loaded biochar prepared at CO2 and 400 °C has lower cumulative release ratio of 82.35 %, and could retain the durative K release at ~0.5 % for 25 d. The release kinetics suggested that the K release behavior was dominated by dissolution, electrostatic attraction, adsorption, confinement effect, and chemical interaction. Furthermore, pot experiments revealed that K-loaded biochar could promote the growth of Komatsuna, in which the fresh weight and chlorophyll relative content of Komatsuna cultivated with biochar prepared at CO2 and 400 °C reached 0.146 g and 41.95 after 25 d growth, respectively. The above results suggested that the K-loaded biochar exhibited excellent utilization potential as a controlled-release K fertilizer, facilitating the sustainable development and resource valorization of Baijiu industry.

Polyphenol modified natural collagen fibrous network towards sustainable and antibacterial microfiltration membrane for efficient water disinfection.

Because of their low-cost and high bacterial interception efficiency, large-scale membrane separation technologies like microfiltration (MF) have been widely implemented for water disinfection. However, lack of antibacterial ability and low sustainability are two major drawbacks of most petroleum-based MF membranes, which are normally associated with hazardous issues including biofouling and nonbiodegradable waste. In this work, abundant animal hides, which are by-products of the meat processing industry, were proposed as raw materials to fabricate a sustainable MF membrane due to their natural, hierarchical, and renewable collagen fibrous network (CFN) with inherent biodegradability. After the removal of non-collagen compositions from animal hides, such as hair and fat, through a facile pretreating process base on green chemistry principles, a thin CFN based membrane (CFN-M) with a similar micropore size to that of commercial MF membranes could be produced. Furthermore, inspired by conventional leather tanning technology, tannic acids (TA) were selected as plant polyphenol tanning agent to modify collagen fibers based on tanning chemistry to improve the thermal stability of CFN-M. Moreover, the TA cross-linked CFN-M (TA@CFN-M) exhibited excellent antibacterial properties due to the production of reactive oxygen species (ROS) by the catechol functional group. The resulting TA@CFN-M achieved >99.9% water disinfection efficiency with a flux of ∼150 L m-2 h-1 via gravity-driven operation, while simultaneously showing admirable anti-biofouling ability. Different from the commercial MF membrane, based on the green chemistry principle, this work may shed light on designing new sustainable and antibacterial membranes for anti-biofouling water disinfection.

Hierarchical collagen fibers complexed with tannic acid and Fe3+ as a heterogeneous catalyst for enhancing sulfate radical-based advanced oxidation process.

Efficient sulfate radical-based advanced oxidation processes (SR-AOPs) are important for treating organic contaminants of industrial wastewater. To achieve this goal, tannic acid (TA)-modified skin collagen fibers (CFs) were prepared for the enhanced immobilization of Fe3+ based on multiple complexation interactions, resulting in a heterogeneous catalyst with more catalytic sites (defined as TA-Fe-CFs) for activating peroxymonosulfate (PMS). During the removal of an organic dye (rhodamine B, RhB) from water, the hierarchical TA-Fe-CFs exhibited excellent adsorption capacity at the early stage before the introduction of PMS, which can be ascribed to the π-π interaction between TA and aromatic RhB. Such improved mass transfer of target contaminants into the catalytic support was proved to be beneficial for improving the utilization efficiency of sulfate radicals in subsequent SR-AOPs. After introducing PMS, the reductive TA moieties of the heterogeneous catalyst were able to accelerate the redox cycle of Fe3+/Fe2+ in Fenton reactions, facilitating the activation of PMS to generate sulfate radicals for the degradation of organic RhB.

Polyethyleneimine/hydrated titanium oxide-functionalized fibrous adsorbent for removing cobalt: Adsorption performance and irradiation stability.

Radionuclides of 60Co often encountered in the fields of radiation therapy, medical preparation, and equipment sterilization, which have been considered fatal. Therefore, developing efficient and irradiation-stable adsorbents for the removal of 60Co in wastewater is urgently needed. An irradiation-stable fibrous adsorbent was fabricated through the surface functionalization of collagen fibers (CFs) by polyethyleneimine (PEI) and hydrated titanium oxide (TiO) (PEI-TiO-CFs). PEI-TiO-CFs, including their adsorption performance and irradiation stability, were systematically investigated. Results showed that PEI-TiO-CFs exhibit a maximum adsorption capacity of 0.5575 mmol g-1. In addition, the adsorption capacity of PEI-TiO-CFs only demonstrated a slight decrease in the selectivity investigation of Co2+ mixed with another coexisting ion, such as Na+, K+, and NO3-, Cl-. Furthermore, breakthrough point of PEI-TiO-CFs in column is high at 80 BV (bed volume) and the PEI-TiO-CF column can be mostly regenerated using 12 BV of Na2EDTA solution. Excellent irradiation stability of PEI-TiO-CFs was confirmed by the maintained morphology and adsorption capacity after irradiation at 350 kGy of 60Co γ-ray. Results indicated that PEI-TiO-CFs are an effective adsorbent for radioactive cobalt removal from aqueous solutions.

Natural polyphenol-based nanoengineering of collagen-constructed hemoperfusion adsorbent for the excretion of heavy metals.

Designing a hemoperfusion adsorbent for the excretion therapy of toxic heavy metals still remains a great challenge due to the biosafety risks of non-biological materials and the desired highly efficient removal capacity. Herein, inspired from the homeostasis mechanism of plants, natural polyphenols are integrated with collagen matrix to construct a polyphenol-functionalized collagen-based artificial liver (PAL) for heavy metals excretion and free radicals scavenging therapy. PAL presents high adsorption capacities for Cu2+, Pb2+, and UO22+ ions, up to 76.98 µmol g-1, 106.70 µmol g-1, and 252.48 µmol g-1, respectively. Remarkably, PAL possesses a high binding affinity for UO22+, Pb2+, and Cu2+ ions even in the complex serum environment with the presence of biologically-relevant ions (e.g., Mg2+, Ca2+ ions). Low hemolysis ratio (1.77%), high cell viability (> 85%), high plasma recalcification time (17.4 min), and low protein adsorption (1.02 µmol g-1) indicate outstanding biocompatibility of this material. This natural polyphenol/collagen-based fully bio-derived hemoperfusion adsorbent provides a novel and potentially applicable strategy for constructing a hemoperfusion adsorbent for heavy metal ions excretion therapy with efficiency and biosafety.

Irradiation-stable hydrous titanium oxide-immobilized collagen fibers for uranium removal from radioactive wastewater.

Developing efficient adsorbents with radiation stability for uranium removal from nuclear wastewater is greatly important for resource sustainability and environmental safety in manufacturing nuclear fuel. A novel adsorbent of hydrous titanium oxide-immobilized collagen fibers (HTO/CFs) with good radiation stability for UO22+ removal was developed. Results showed that the adsorption capacity of HTO/CFs for UO22+ was 1.379 mmol g-1 at 303 K and pH 5.0 when the initial concentration of UO22+ was 2.5 mmol L-1. Moreover, HTO/CFs showed high selectivity for U(VI) in bilateral mixed solution including UO22+ with another coexisting ion, such as Cl-, NO3-, Zn2+, and Mg2+. The adsorption behavior of UO22+ from radioactive wastewater on HTO/CF column was also investigated, and the breakthrough point was approximately 250 BV (bed volume). Notably, the HTO/CFs column can be rapidly regenerated by using only 4.0 BV of 0.1 mol L-1 HNO3 solution. The regenerated HTO/CFs column exhibited slight change in the breakthrough curve, suggesting its excellent reapplication ability. Furthermore, after irradiation under 60Co γ-ray at total doses of 10-350 kGy, HTO/CFs still preserved fibrous morphology and adsorption capacity, indicating significant radiation stability. These results demonstrate that HTO/CFs are industrial scalable adsorbents for the adsorptive recovery of uranium.

Lightweight and Flexible Bi@Bi-La Natural Leather Composites with Superb X-ray Radiation Shielding Performance and Low Secondary Radiation.

A high-shielding, low secondary radiation, lightweight, flexible, and wearable X-ray protection material was prepared by coimpregnating La2O3 and Bi2O3 nanoparticles in natural leather (NL) with an additional Bi2O3 coating at the bottom surface of the leather. The prepared Bi28.2@Bi3.48La3.48-NL (28.2 and 3.48 mmol·cm-3 are the loading contents of elements) showed excellent X-ray shielding ability (65-100%) in a wide energy range of 20-120 keV with reduced scattered secondary radiation (30%). The bottom surface coating played a critical role in enhancing the X-ray attenuation and reducing the scattered secondary radiation by reflecting and deflecting incident X-ray photons. Excellent mechanical property with superb bending resistance of the NL matrix was properly maintained, and its tensile strength and tearing load were 15.39 MPa and 25.81 N·mm-1, respectively. This lightweight and wearable high-performance protection material can facilitate safety and comfortability during intensive activities of practitioners in the health care industry.

Collagen Peptide Provides Saccharomyces cerevisiae with Robust Stress Tolerance for Enhanced Bioethanol Production.

Efficient production of bioethanol is desirable for bioenergy large-scale applications, but it is severely challenged by ethanol and sugar stresses. Here, collagen peptide (CP), as a renewable nitrogen-containing biomass, remarkably enhanced the stress resistance of Saccharomyces cerevisiae SLL-510 against ethanol challenge, based on its unique amino acid composition. Transcriptome analysis showed that the energy, lipid, cofactor, and vitamin metabolism may involve in stress tolerance provided by CP. When CP was added into the media containing 249.99 mg/mL glucose, the bioethanol yield increased from 8.03 to 12.25% (v/v) and 11.35 to 12.29% (v/v) at 43 and 120 h, respectively. Moreover, at 286.79 mg/mL glucose, the highest yield reached 14.48% (v/v), with 99.58% glucose utilization rate. The protection and promotion effects of CP were also shown by four other industrial S. cerevisiae strains. These results coupled with the advantages of abundant reserves, cleanliness, and renewability revealed that CP is a promising economically viable and industrially scalable enhancer for bioethanol fermentation.

Research on X-ray shielding performance of wearable Bi/Ce-natural leather composite materials.

Natural leather (NL) based composite protection materials with lightweight, flexibility, wearability and high shielding efficiency will remarkably innovate the current research on X-ray protection materials. A co-doped Bi/Ce-NL composite with outstanding X-ray attenuation in the energy range of 20-120 keV is successfully fabricated. The uniform distribution of Bi2O3 and CeO2 nanoparticles in the hierarchical structure of natural leather significantly promotes the X-ray attenuation by improving the weak absorption region of Bi with Ce via synergistic effects of the two elements. The fabricated Bi/Ce-NL loading with 0.755 mmol cm-3 Bi2O3 and 1.51 mmol cm-3 CeO2 achieves approximately 100% X-ray shielding when the energy below 40 keV. Thus, the fabricated Bi/Ce-NL with superb X-ray attenuation can safely and comfortably protect human from the risk of X-ray exposure with low bulk density, high water vapor permeability, exceptional mechanical properties and excellent bending resistance, presenting significant advantages in wearability and flexibility compared to both traditional lead-based and polymer-based protection materials.

Advanced X-ray Shielding Materials Enabled by the Coordination of Well-Dispersed High Atomic Number Elements in Natural Leather.

Nowadays, X-rays are playing increasingly important roles in daily life and industrial manufacture, which calls for effective and mobile shielding materials. However, it seems to be a paradox to prepare shielding materials simultaneously achieving excellent X-ray attenuation properties and superior mechanical strength. Here, an advanced leather-based X-ray shielding material containing bismuth and iodine (BiINP-LM) is prepared, and the stable and well-dispersed loading of high-Z element components is enabled by favorable interactions between bismuth iodide and leather, i.e., coordination, hydrogen bonds, and electrostatic attractions. A piece of BiINP-LM with 1.00 mm thickness displays an excellent X-ray attenuation efficiency of more than 90% in the photon energy range below 50 keV and 65% at 83 keV, which averagely exceeds ∼3% than that of the 0.25 mm lead plate and ∼5% than that of the 0.65 mm commercial lead apron. Additionally, the coordination between bismuth and leather provides an enhanced tensile and tear strength of ∼10-fold and 3-fold compared with the lead apron. It is worth mentioning that BiINP-LM also displays extra high water-vapor permeability, which is ∼50-fold more than the lead apron. Overall, this work opens up a new prospect for preparing advanced X-ray shielding materials with both excellent X-ray attenuation and outstanding physiomechanical performances.

Prevention of Bacterial Colonization Based on Self-Assembled Metal-Phenolic Nanocoating from Rare-Earth Ions and Catechin.

Clinically related infection is a critical risk for human health and is usually caused by biofilm formation on medical devices. Herein, typical polyphenols, catechin (Cat), and rare-earth ions (Re3+) were used for self-assembled Cat-Re nanoparticles that can be facilely coated on the surface of a polyamide (PA) membrane to synergistically prevent bacterial adhesion and subsequent biofilm formation. The antibacterial adhesion feature of the assembled Cat-Re nanoparticles coated on the PA membrane surface was assessed using Pseudomonas aeruginosa, one of the most common pathogenic bacteria, as probe bacteria under static and dynamic simulation flow conditions. The Cat-Re nanocoating showed excellent antibacterial and anti-adhesion activities against P. aeruginosa and successfully prevented biofilm formation on the material's surface. Regardless of the conditions, the Cat-Re nanocoating significantly suppressed the growth and attachment of P. aeruginosa and maintained >90% inhibition activity with favorable reusability and long-term stability. The results suggest that the self-assembled rare-earth-phenolic nanocoating has promising application potential in the prevention of medical device-related biofilm formation.

Synthesis of Catechin-Rare Earth Complex with Efficient and Broad-Spectrum Anti-Biofilm Activity.

Biofilm is the crucial reason of clinical infections. Herein, green tea based polyphenol (catechin) and rare earth (RE) metal ions were employed for the preparation of catechin-RE complexes with significant anti-biofilm properties. The complexes were characterized by FT-IR, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and dynamic light scattering (DLS), which suggested that catechin coordinated with RE3+ through its ortho phenolic hydroxy groups. The prepared catechin-RE showed significant effects in anti-biofilm growth against P. aeruginosa (Gram-negative bacteria), S. sciuri (Gram-positive bacteria), and A. niger (fungi), which significantly exceeded the utilization of catechin or RE3+ . Morphological observations indicated that catechin supplied cell affinity to transfer RE3+ and helped to damage cell membrane, which act as a carrier to exert cytotoxicity of RE3+ to realize anti-biofilm. Differential gene expression analysis described gene expression changes induced by catechin-RE, including 56, 272 and 2160 downregulated genes for P. aeruginosa, S. sciuri and A. niger, respectively, which suggested critical changes in cellular metabolism, growth and other processes. These results illustrate the outstanding superiority of catechin-RE complexes in anti-infection aspect, i. e., the green tea based rare earth complexes are promising candidates for anti-biofilm applications to address serious challenges in the prevention of multiple infections.

Radionuclide tolerance mechanism of plants for ultraselective enrichment of low content of thorium with exceptional selectivity coefficient.

Selective enriching low content of radionuclides from radioactive wastewater is a critical issue for environmentally benign utilization of nuclear power. Inspired by the tolerance mechanism of plants to radionuclides, we developed a pH-triggered ultraselective coordinative adsorption (CA) membrane. The as-prepared CA membrane featured the advantages of both coordinative adsorption and membrane separation, including ultrahigh selectivity coefficient of 1242, large capacity (80 L m-2) and short mass transfer distance. The adsorption isotherms of Th4+ on the CA membrane were well described by the Freundlich model (R2 > 0.99), and the adsorption kinetics have a good fitting by using the pseudo-second-order kinetic model (R2 > 0.99). In a continuous separation under gravity, the CA membrane was able to selectively enrich the low content of Th4+ (0.05 mmol L-1) in the presence of 700 folds (35 mmol L-1) of co-existing ions (Na+, Mg2+, K+, Ca2+, Sr2+, Cs+ and Ba2+). The exceptional extraction efficiency to Th4+ was 100%, superior to that (3.7%) of all co-existing ions. Notably, the Th4+ enriched on the CA membrane was facilely eluted by diluted HNO3 (0.1 mol L-1). The Th4+ in the eluents was enriched by up to 54 folds. The eluted CA membrane was further reused for selective enrichment of Th4+, which showed no obvious loss of selectivity and enrichment capability. Our strategy might open up a new strategy for realizing ultraselective and recyclable enrichment of low content of irradiation contaminants from wastewater.

Targeted Therapy against Metastatic Melanoma Based on Self-Assembled Metal-Phenolic Nanocomplexes Comprised of Green Tea Catechin.

The targeted therapy of metastatic melanoma is an important yet challenging goal that has received only limited attention to date. Herein, green tea polyphenols, (-)-epigallocatechin-3-gallate (EGCG), and lanthanide metal ions (Sm3+) are used as building blocks to engineer self-assembled SmIII-EGCG nanocomplexes with synergistically enhanced tumor inhibitory properties. These nanocomplexes have negligible systemic toxic effects on healthy cells but cause a significant reduction in the viability of melanoma cells by efficiently regulating their metabolic pathways. Moreover, the wound-induced migration of melanoma cells can be efficiently inhibited by SmIII-EGCG, which is a key criterion for metastatic melanoma therapy. In a mouse melanoma tumor model, SmIII-EGCG is directly compared with a clinical anticancer drug, 5-fluorouracil and shows remarkable tumor inhibition. Moreover, the targeted therapy of SmIII-EGCG is shown to prevent metastatic lung melanoma from spreading to main organs with no adverse side effects on the body weight or organs. These in vivo results demonstrate significant advantages of SmIII-EGCG over its clinical counterpart. The results suggest that these green tea-based, self-assembled nanocomplexes possess all of the key traits of a clinically promising candidate to address the challenges associated with the treatment of advanced stage metastatic melanoma.

Glycine betaine enhances biodegradation of phenol in high saline environments by the halophilic strain Oceanobacillus sp. PT-20.

The halophilic bacterial strain PT-20, isolated from saline alkali soil samples and identified as a member of the genus Oceanobacillus, exhibited a robust ability to degrade phenol under high salt conditions. It was determined that strain PT-20 was capable of degrading 1000 mg L-1 phenol completely in the presence of 10% NaCl within 120 h. Under the optimal degradation conditions, pH 8.0, 3% NaCl and 30 °C, 1000 mg L-1 phenol could be completely degraded in 48 h. Interestingly, the biodegradation rate of phenol was dramatically improved in the presence of glycine betaine. When glycine betaine was added, the time required to degrade 1000 mg L-1 phenol completely was significantly reduced from 120 h to 72 h, and the corresponding average degradation rate increased from 8.43 to 14.28 mg L-1 h-1 with 10% NaCl. Furthermore, transcriptome analysis was performed to investigate the effects of phenol and glycine betaine on the transcriptional levels of strain PT-20. The results indicated that the addition of glycine betaine enhanced the resistance of cells to phenol, increased the growth rate of strain PT-20 and upregulated the expression of related enzyme genes. In addition, the results of enzyme activity assays indicated that strain PT-20 degraded phenol mainly through a meta-fission pathway.

Self-Assembled Metal-Phenolic Nanoparticles for Enhanced Synergistic Combination Therapy against Colon Cancer.

Engineering functional nanomaterials to have both high therapeutic efficacy and minimal side-effects has become a promising strategy for next-generation cancer treatments. Herein, an adenosine triphosphate (ATP) depletion and reactive oxygen species-enhanced combination chemotherapy platform is introduced whereby therapeutic samarium (Sm3+ ) ions and (-)-epicatechin (EC) are integrated via a metal-phenolic network (SmIII -EC). The independent pathway between Sm3+ and EC can achieve a synergistic therapeutic effect through the mitochondrial dysfunction process. SmIII -EC nanoparticles cause a significant reduction of viability of C26 murine colon carcinoma cells while with lower systemic toxic effects on normal cell lines. SmIII -EC nanoparticles are used to directly compare with a clinic anticancer drug 5-fluorouracil. SmIII -EC nanoparticles not only decrease the tumor volume but also do not affect the body weight of mice and normal organs, showing significant advantages over clinic counterpart. These facts suggest that SmIII -EC nanoparticles represent a clinically promising candidate for colon cancer treatment with a targeted therapeutic effect and minimum side toxicity.

Controllable Synthesis of Monolayer Poly(acrylic acid) on the Channel Surface of Mesoporous Alumina for Pb(II) Adsorption.

Polymer/inorganic nanocomposites exhibit special properties due to highly intimate interactions between organic and inorganic phases and thus have been deployed for various applications. Among them, nanocomposites with monolayer polymer coverage on the inorganic surface demonstrate the highest efficiency for applications. However, the controllable synthesis of the polymer monolayer in mesopores of inorganic substrates remains a challenge. In this study, poly(acrylic acid)/γ-alumina nanocomposites (PAA/alumina) were synthesized via the in situ polymerization of acrylic acid impregnated in mesopores of alumina. By applying the preneutralization of monomers, the polymerization was found to be highly controllable in generating monolayer PAA coverage. The formation of monolayers was verified by thermogravimetry, semiquantitative Fourier transform infrared spectroscopy, N2 adsorption-desorption, and Pb(II) adsorption. Alternatively, the organic loadings of PAA/alumina composite samples could be controlled in the range of 0.2 to 1.0 equiv of monolayer, together with the linearly correlated metal ion adsorption capacity. As calculated by the complexation model, one Pb(II) is combined with two carboxylate groups of PAA. The formation of the monolayer polymer inside mesoporous oxide channels represents a method for the development of highly promising functional nanocomposites.

Absorption and Reflection Contributions to the High Performance of Electromagnetic Waves Shielding Materials Fabricated by Compositing Leather Matrix with Metal Nanoparticles.

Leather matrix (LM), a natural dielectric material, features a hierarchically suprafibrillar structure and abundant dipoles, which provides the possibility to dissipate electromagnetic waves (EW) energy via dipole relaxation combined with multiple diffuse reflections. Conventionally, metal-based materials are used as EW shielding materials due to that their high conductivity can reflect EW effectively. Herein, a lightweight and high-performance EW shielding composite with both absorption and reflection ability to EW was developed by coating metal nanoparticles (MNPs) onto LM. The as-prepared metal/LM membrane with only 4.58 wt % of coated MNPs showed excellent EW shielding effectiveness of ∼76.0 dB and specific shielding effectiveness of ∼200.0 dB cm3 g-1 in the frequency range of 0.01-3.0 GHz, implying that more than 99.98% of EW was shielded. Further investigations indicated that the high shielding performances of the metal/LM membrane were attributed to the cooperative shielding mechanism between LM and the coating of MNPs.

Adaptations of Bacillus shacheensis HNA-14 required for long-term survival under osmotic challenge: a multi-omics perspective.

Genomic sequence, transcriptomic, metabolomic and fatty acid analyses of strain HNA-14 were performed to understand the mechanism of salt tolerance for long-term survival. The results indicated that strain HNA-14 has different osmotic resistance mechanisms for long-term survival and short-term salt stress. The cells mainly synthesized compatible solutes to resist osmotic pressure when cultured under nutrient deficient conditions, while they can slow down the synthesis rate and uptake from the environment when cultured under a nutritionally rich environment. Also, the amounts of branched and unsaturated fatty acids in the cell membrane are maintained to a high degree (>50%) to maintain the fluidity of the cell membrane; when the cells are cultured in a high osmotic environment for long-term survival, they may increase the content of branched fatty acids and phosphoric fatty acids to increase the fluidity of the cell membrane to resist the high osmotic pressure.