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Marine oil exploration is important yet greatly increases the risk of oil leakage, which will result in severe environment pollution and economic losses. It is an urgent need to develop effective underoil adhesives. However, realizing underoil adhesion is even harder than those underwater, due to the stubborn attachment of a highly viscous oil layer on target surface. Here, inspired by endocytosis, a tough gel tape composed of zwitterionic polymer network and zwitterionic surfactants is developed. The amphiphilic surfactants can form micelle to capture the oil droplets and transport them from the interface to gel via electrostatic attraction of polymer backbone, mimicking the endocytosis and achieving robust underoil adhesion. Benefiting from the oil-resistance of polymer backbone, the gel further realizes a combination of i) long-term adhesion with high durability, ii) repeated adhesion in oil, and iii) renewable adhesion efficiency after exhausted use. The tape exhibits an ultra-high adhesive toughness of 2446.86 J m-2 to stainless steel in silicone oil after 30 days' oil-exposure; such value of adhesive toughness surpasses many of those achieved in underwater adhesion and is greater than underoil adhesion performance of commercial tape. The strategy illustrated here will motivate the design of sustainable and efficient adhesives for wet environments.

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Microcarriers for large-scale cell culture have a broader prospect in cell screening compared with the traditional high cost, low efficiency, and cell damaging methods. However, the equal biological affinity to cells has hindered its application. Therefore, based on the antifouling strategy of zwitterionic polymer, we developed a cell-specific microcarrier (CSMC) for shielding non-target cells and capturing mesenchymal stem cells (MSCs), which has characteristics of high biocompatibility, low background noise and high precision. Briefly, [2-(methacryloyloxy) ethyl] dimethyl-(3-sulfopropyl) ammonium hydroxide and glycidyl methacrylate were grafted onto polygalacturonic acid, respectively. The former built a hydration layer through solvation to provide an excellent antifouling surface, while the latter provided active sites for the click reaction with sulfhydryl-modified cell-specific peptides, resulting in rapid immobilization of peptides. This method is applicable to the vast majority of polysaccharide materials. The accurate capture ratio of MSCs by CSMC in a mixed multicellular environment is >95 % and the proliferation rate of MSCs on microcarriers is satisfactory. In summary, this grafting strategy of bioactive components lays a foundation for the application of polysaccharide materials in the biomedical field, and the specific adhesive microcarriers also open up new ideas for the development of stem cell screening as well.

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The cryoprotectant potential of 3-(1-(2-(2-methoxyethoxy)ethyl)imidazol-3-io)butane-1-carboxylate (OE2imC3C) for proteins necessitates assessment to elucidate its relationship with protein hydration. To reveal this relationship, we assessed the protein stability (pre-freezing and post-thawing) and melting behavior in dilute aqueous protein-OE2imC3C solutions containing varying mole fractions (x) of OE2imC3C (x = 0, 7.7 × 10-3, and 1.7 × 10-2) using Fourier-transform infrared (FTIR) and near-UV circular dichroism (near-UV CD) spectroscopy and differential scanning calorimetry (DSC) techniques. Following freezing/thawing using a deep freezer, protein stability in aqueous OE2imC3C solutions (x = 1.7 × 10-2) preserved the folded state owing to the protein-OE2imC3C interaction, whereas stability at x = 7.7 × 10-3 was reduced. These results indicate that the protein cryoprotectant potential in aqueous OE2imC3C solutions at x = 1.7 × 10-2 is higher than that at x = 7.7 × 10-3, owing to the preferential binding of OE2imC3C with proteins.

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During invisalign treatment, as salivary proteins or glycoproteins fill the space between the teeth and the aligners, they can easily adhere to the teeth, forming an acquired cellular film on which bacteria are highly susceptible to colonizing, which in turn leads to the development of enamel white staining lesions (WSLs), one of the major complications of orthodontic treatment. Inhibiting the activity of cariogenic bacteria while promoting the remineralization of demineralized enamel is the key to preventing and treating WSLs. Currently, the drug commonly used in clinical practice for the treatment of WSLs is silver diamine fluoride, which, although it has both antimicrobial and remineralizing effects, suffers from problems such as pulpal irritation and tooth discoloration. In this study, based on the principle of coordination chemistry, copper ions and plant polyphenol tannins were assembled on invisible orthodontic aligners to form a metal-phenol network coating (TA-Cu MPNs), and zwitterionic sulfonamethyldopamine was introduced for bionic mineralization to obtain the multifunctional coating TA-Cu MPNs@ZDS@CaP (TZC). The coating exhibits acid-responsive release of Ca2+ and PO4 3-, and the decomposed CaP layer can be regenerated by a simple dipping method. The TZC coating strongly inhibits common cariogenic bacteria and their biofilms. In addition, the results of the in vitro mineralization experiment show that TZC-coated invisible orthodontic aligner treatment of demineralized enamel has significant remineralization effects. It is worth mentioning that the constructed coating has a durable antibacterial effect and can meet the service cycle of invisible orthodontic aligners. This study provides theoretical and experimental bases for the prevention or treatment of WSLs in invisible orthodontic treatment.

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Indocyanine green (ICG), the only near-infrared (NIR) dye approved for clinical use, has received increasing attention as a theranostic agent wherein diagnosis (fluorescence) is combined with therapy (phototherapy), but suffers rapid hepatic clearance, poor photostability, and limited accumulation at tumor sites. Here we report that dimerized ICG can self-assemble to form zwitterionic nanoparticles (ZN-dICG), which generate fluorescence self-quenching but exhibit superior photothermal and photodynamic properties over ICG. The zwitterionic moieties confer ZN-dICG an ultralow critical micelle concentration and high colloidal stability with low non-specific binding in vivo. In addition, ZN-dICG can respond to the over-generated reactive oxygen species (ROSs) and dissociate to restore NIR fluorescence of ICG, amplifying the sensitivity via albumin binding for low-background imaging of tumors. Following systemic administration, ZN-dICG accumulated in tumors of xenograft-bearing mice for imaging primary and metastatic tumors, and induced tumor ablation under laser irradiation. The discovery of ZN-dICG would contribute to the design of translational phototheranostic platform with high biocompatibility. STATEMENT OF SIGNIFICANCE: Indocyanine green (ICG) has been extensively studied as a phototheranostic agent that combines imaging with phototherapies, but it suffers from rapid hepatic clearance, poor photostability, and limited accumulation at tumor sites. Here, we report a strategy to construct ICG dimers (ICG-tk-ICG) by conjugating two ICG molecules via a thioketal bond, which can self-assemble into zwitterionic nanoparticles (ZN-dICG) at ultralow critical micelle concentrations, exhibiting superior photothermal and photodynamic properties over ICG. ZN-dICG responds to the over-generated ROS in tumors and dissociates to restore the NIR fluorescence of ICG, enhancing the sensitivity via albumin binding for low-background imaging of tumors. This study offers a supramolecular strategy that may potentiate the clinical translation of ICG in imaging-guided cancer phototherapy.

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A novel zwitterion composed of an imidazolium tethered to an anionic sulfonyl(trifluoromethane sulfonyl)imide group was prepared as an alternative dielectric material to traditional ionic liquids. The zwitterion not only melted below 100 °C but also proved to be nonhygroscopic. High-capacitance organic dielectric materials were obtained by blending this compound with poly(methyl methacrylate) over a range of concentrations and thicknesses. Above a specific temperature and concentration, films exhibit a capacitance nearly equivalent to that of an electrostatic double layer, approximately 10 µF/cm2, regardless of their thickness. Grazing-incidence wide-angle X-ray scattering experiments suggest that the zwitterions adopt a lamellar ordering at their surface above a critical concentration. The observed ordering is correlated with a 1000-fold increase in capacitance. The behavior suggests that the zwitterions exhibit strong electrostatic correlations throughout the film bulk, pointing the way toward a novel class of organic dielectric materials.

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Biofouling on marine surfaces causes immense material and financial harm for maritime vessels and related marine industries. Previous reports have shown the effectiveness of amphiphilic coating systems based on poly(dimethylsiloxane) (PDMS) against such marine foulers. Recent studies on biofouling mechanisms have also demonstrated acidic microenvironments in biofilms and stronger adhesion at low-pH conditions. This report presents the design and utilization of amphiphilic polymer coatings with buffer functionalities as an active disruptor against four different marine foulers. Specifically, this study explores both neutral and zwitterionic buffer systems for marine coatings, offering insights into coating design. Overall, these buffer systems were found to improve foulant removal, and unexpectedly were the most effective against the diatom Navicula incerta.

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Dialysis membranes are not hemocompatible with human blood, as the patients are suffering from the blood-membrane interactions' side effects. Zwitterionic structures have shown improved hemocompatibility; however, their complicated synthesis hinders their commercialization. The goal of the study is to achieve fast functionalization for carboxybetaine and sulfobetaine zwitterionic immobilization on PES membranes while comparing the stability and the targeted hemocompatibility. The chemical modification approach is based on an aminolysis reaction. Characterization, computational simulations, and clinical analysis were conducted to study the modified membranes. Atomic force microscopy (AFM) patterns showed a lower mean roughness for carboxybetaine-modified (6.3 nm) and sulfobetaine-modified (7.7 nm) membranes compared to the neat membrane (52.61 nm). The pore size of the membranes was reduced from values above 50 nm for the neat PES to values between 2 and 50 nm for zwitterionized membranes, using Brunauer-Emmett-Teller (BET) analysis. More hydrophilic surfaces led to a growth equilibrium water content (EWC) of nearly 6% for carboxybetaine and 10% for sulfobetaine-modified membranes. Differential scanning calorimetry (DSC) measurements were 12% and 16% stable water for carboxybetaine- and sulfobetaine-modified membranes, respectively. Sulfobetaine membranes showed better compatibility with blood with respect to C5a, IL-1a, and IL-6 biomarkers. Aminolysis-based zwitterionization was found to be suitable for the improvement of hemodialysis membranes. The approach introduced in this paper could be used to modify the current dialysis membranes with minimal change in the production facilities.

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Polymeric room-temperature phosphorescence (RTP) materials especially multicolor RTP systems hold great promise in concrete applications. A key feature in these applications is a triplet charge transfer transition. Aromatic electron donors and electron acceptors are often essential to ensure persistent RTP. There is much interest in fabricating non-aromatic charge-transfer-mediated RTP materials and it still remains a formidable challenge to achieve color-tunable RTP via charge transfer. Herein, a charge-transfer-mediated RTP material by embedding quinoline derivatives within a non-aromatic polymer matrix such as polyacrylamide (PAM) or polyvinyl alcohol (PVA) is developed. Through-space charge transfer (TSCT) is achieved upon alkali- or heat treatment to realize a long phosphorescence lifetime of up to 629.90 ms, high phosphorescence quantum yield of up to 20.51%, and a green-to-blue afterglow for more than 20 s at room temperature. This color-tunable RTP emerges from a nonaromatic polymer to single phosphor charge transfer that has rarely been reported before. This finding suggests that an effective and simple approach can deliver new color-tunable RTP materials for applications including multicolor display, information encryption, and gas detection.

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Zwitterionic polymers have emerged as an important class of biomaterials to construct wound dressings and antifouling coatings over the past decade due to their excellent hydrophilicity. However, all the reported zwitterionic polymers as wound dressings are nondegradable because of noncleavable carbon─carbon bonding backbones, and must be removed periodically after treatment to avoid hypoxia in the wound, thus leading to potential secondary injury. In this work, a biodegradable polyzwitterion patch is fabricated for the first time by ring-opening polymerization of carboxybetaine dithiolane (CBDS), which is self-crosslinked via inter-amide hydrogen bonds and zwitterionic dipole-dipole interactions on the side chains. The unprecedented polyCBDS (PCBDS) patch demonstrates enough ductility owing to the intermolecular physical interactions to fully cover irregular wounds, also showing excellent biodegradability and antifouling performance resulted from the existence of disulfide bonds and carboxybetaine groups. Besides, the PCBDS degradation-induced released CBDS owns potent antioxidant and antibacterial activities. This PCBDS patch is used as a diabetic wound dressing, inhibiting bacterial adhesion on the external surface, and its degradation products can exactly kill bacteria and scavenge excessive reactive oxygen species (ROS) at the wound site to regulate local microenvironment, including regulation of cytokine express and macrophage polarization, accelerating infected diabetic wound repair, and also avoiding the potential secondary injury.

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Blood-contact medical devices are indispensable for clinical interventions, yet their susceptibility to thrombosis and bacterial infections poses substantial risks to treatment efficacy and patient well-being. This study introduces a polysulfobetaine/alginate-CuII (SAC) zwitterionic hydrogel coating on polyurethane (PU) surfaces. This approach retains the superhydrophilic and antifouling nature of pSBMA while conferring the antibacterial effects of copper ions. Meanwhile, the copper alginate network intertwines with the polysulfobetaine (pSBMA) network, enhancing its mechanical properties and overcoming inherent weaknesses, thereby improving coating durability. Compared to the substrate, the SAC hydrogel coating significantly reduces thrombus adhesion mass by approximately 81.5% during extracorporeal blood circulation and effectively prevents bacterial biofilm formation even in a high-concentration bacterial milieu over 30 days. Moreover, the results from an isolated blood circulation model in New Zealand white rabbits affirm the impressive anticoagulant efficacy of the SAC hydrogel coating. The findings suggest that this hydrogel coating and its application method hold promise as a solution for blood-contact material surface modification to address thrombosis and bacterial biofilm formation simultaneously.

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Objective: For liquid biopsy of cancer, the extraction of circulating cell-free DNA (cfDNA) from plasma is required. We evaluated the efficacy of use of magnetic submicron particles coated with abundant small zwitterions (MSP-ZEWBs) for extracting short fragments of cfDNA. Methods: We developed and optimized an MSP-ZEWB-based cfDNA extraction method using ampholytic ion-exchange materials and compared its results with those using a control kit. We measured the cfDNA concentration by quantitative polymerase-chain-reaction and using the Qubit method and analyzed cfDNA fragmentation patterns using a bioanalyzer. Results: The fragment size of cfDNA isolated from glycine hydrochloric acid at a pH of 2.2 exhibited a better alignment with the DNA marker. The highest DNA intensity was observed at the final concentration of 0.8% polyethylene glycol 8000. The intensity of cfDNA decreased significantly when isolated from plasma with DNA marker using MSP-ZEWBs with an adsorption buffer containing guanidine hydrochloride or isothiocyanoguanidine. All fragments were successfully extracted using MSP-ZEWBs from both plasma and phosphate-buffered saline. Notably, the intensity of short cfDNA fragments isolated using MSP-ZEWBs remained consistent for recovery of long DNA fragments. indicating a potential selective of small fragments. Conclusion: The extraction of plasma cfDNA with MSP-ZEWBs requires no protein denaturation, shows resistance to cells remaining in plasma, and demonstrates higher overall efficiency and better reproducibility than other extraction methods. Use of MSP-ZEWBs may greatly enhance liquid biopsy of cancers through the analysis of plasma cfDNA in clinical practice.

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Chromatographic behavior of novel chiral stationary phases with bonded selectors based on Cinchona alkaloids modified with dipeptides was studied using dipeptides as probe molecules. Buffer-free and salt containing hydro-organic solutions were used as the mobile phases. The selectors exhibit pseudoenantiomeric behavior with respect to the L/D or LL/DD enantiomers and do not behave so with respect to the LD/DL enantiomers. The alkaloid part of the selectors is the driver of enantioselectivity, while the dipeptide substituent plays a modulating role. The quinidine-based selectors demonstrate stronger adsorption affinity and higher enantioselectivity as compared to the quinine-based selectors. The dipeptide analytes containing a glycyl fragment are weaker retained and their enantiomers are worse separated comparing to dipeptides with both units being larger amino acids. Moreover, a phenyl group in the structure of a dipeptide analyte facilitates enantioseparation. The effect of the mobile phase composition on retention depends on the hydrophobicity of an analyte. Hydrophobic dipeptides are better eluted by methanol-rich solvents, hydrophilic dipeptides are better eluted with water-rich solvents, and dipeptides with an intermediate hydrophobicity demonstrate a U-shaped or more complicated dependence of the retention factor on the percentage of methanol. Even a small buffer addition to the mobile phase decreases retention, but the ion-exchange mechanism was not confirmed. The effect of an electrolyte is rather due to the shielding of the charged groups of the selector reducing thereby electrostatic interaction between the selector and analyte. Efficiency of the novel columns is comparable to that of other brush-type chiral columns, the highest achieved number of the theoretical plates per 1 m varying between 30,000 and 40,000.

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Five cationic ruthenium-arene complexes with the generic formula [Ru(SAc)(S2C·NHC)(p-cymene)](PF6) (5a-e) were prepared in almost quantitative yields using a straightforward one-pot, two-step experimental procedure starting from [RuCl2(p-cymene)]2, an imidazol(in)ium-2-dithiocarboxylate (NHC·CS2) zwitterion, KSAc, and KPF6. These half-sandwich compounds were fully characterized by various analytical techniques and the molecular structures of two of them were solved by X-ray diffraction analysis, which revealed the existence of an intramolecular chalcogen bond between the oxygen atom of the thioacetate ligand and a proximal sulfur atom of the dithiocarboxylate unit. DFT calculations showed that the C=S…O charge transfer amounted to 2.4 kcal mol-1. The dissolution of [Ru(SAc)(S2C·IMes)(p-cymene)](PF6) (5a) in moist DMSO-d6 at room temperature did not cause the dissociation of its sulfur ligands. Instead, p-cymene was slowly released to afford the 12-electron [Ru(SAc)(S2C·IMes)]+ cation that could be detected by mass spectrometry. Monitoring the solvolysis process by 1H NMR spectroscopy showed that more than 22 days were needed to fully decompose the starting ruthenium-arene complex. Compounds 5a-e exhibited a high antiproliferative activity against human glioma Hs683 and human lung carcinoma A549 cancer cells. In particular, the IMes derivative (5a) was the most potent compound of the series, achieving toxicities similar to those displayed by marketed platinum drugs.

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Cryopreservation techniques are valuable for the preservation of genetic properties in cells, and the development of this technology contributes to various fields. In a previous study, an isotonic freezing medium composed of poly(zwitterion) (polyZI) has been reported, which alleviates osmotic shock, unlike typical hypertonic freezing media. In this study, the primitive freezing medium composed of emerging polyZI is optimized. Imidazolium/carboxylate-type polyZI (VimC3C) is the optimal chemical structure. The molecular weight and degree of ion substitution (DSion) are not significant factors. There is an impediment with the primitive polyZI freezing media. While the polyZI forms a matrix around the cell membrane to protect cells, the matrix is difficult to remove after thawing, resulting in low cell proliferation. Unexpectedly, increasing the poly(VimC3C) concentration from 10% to 20% (w/v) improves cell proliferation. The optimized freezing medium, 20% (w/v) poly(VimC3C)_DSion(100%)/1% (w/v) NaCl aqueous solution, exhibited a better cryoprotective effect.

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Molecules with zwitterionic characteristics exhibit significant potential for utilization in nonlinear optics, optoelectronics, and organic lasers owing to their large dipole moments. Recently, the synthesized compound 2,4-bis (4,5-diphenyl-1H-imidazol-2-yl) phenol (2,4-bImP) by Sakai et al. has been noticed for its unique photochromic properties in solvents [J. Phys. Chem. A, 125 (2021), 4784-4792]. The observed fluorescence in chloroform was attributed to the keto tautomer. Based on the excited state intramolecular proton transfer, the photochromism of 2,4-bImP in chloroform was interpreted as zwitterion production. However, the zwitterion with a specific electronic structure can be in resonance with the conventional neutral structure. The impact of the resonance contribution from the zwitterion and the conventional neutral structure on fluorescence attribution was not taken into account in the previous studies. In this investigation, the ESIPT mechanism of the 2,4-bImP in chloroform has been explored using both the density functional theory and the time-dependent density functional theory. The optimized geometric configuration parameters illustrate the molecular resonant properties. The calculated fluorescence spectra on the basis of the optimization results further corroborate that the fluorescence peaks after proton transfer originates from the resonance of the zwitterionic and the neutral configuration. The zwitterionic nature of the molecule was demonstrated by electrostatic potential and atomic dipole modified Hesfeld atomic charge (ADCH) analysis. Furthermore, the characterization of potential energy curves and IR spectrum further verified the resonance of both the zwitterionic and neutral structures. The results reveal that the 2,4-bImP molecule generates the neutral o-quinoid structure and the zwitterionic structure resonance phenomenon following ESIPT. The aforementioned resonance structure offers novel insights into the ascription of fluorescence. These discoveries establish the theoretical foundation for the exploration and development of zwitterions.

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In the present study, we have synthesized an aminobenzoic acid containing Schiff base (compound 1) and its structure was confirmed through single crystal X-ray study. Importantly, the compound 1 crystallizes in the zwitterionic form, with an anionic carboxylate group (-COO-) and a cationic iminium group (-C = NH+-). The compound 1 is highly soluble in water due to its zwitterionic feature in the solid state. Interestingly, compound 1 acts as a ratiometric fluorescent probe for the selective detection of Al3+ ion in aqueous solution without organic cosolvent. It can also detect Al3+ ion by visual colour change to bluish-green fluorescence under 365 nm UV light. The association constant between compound 1 with Al3+ ion was estimated to be 1.67 × 104 M-1. The lowest detection limit for Al3+ ion was calculated to be 7.05 × 10-8 M in water. Compound 1 in combination with Al3+ ion demonstrated fluorescent imaging potential of the nucleus of in RAW 264.7 murine macrophage cell line. In addition, the sensing model is developed as paper based sensor ''Test Kit' 'for its practical applicability.

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In this study, three small peptoids with different structures, named Sil-peptoids, were developed to improve the separation selectivity of zwitterion-exchange/reversed-phase mixed-mode chromatography stationary phases for multi-component complex drugs. Nonpolar, amphoteric, and alkaline drugs were used as test samples to demonstrate their retention behaviors in reversed-phase, ionic, and mixed-mode interactions. It was observed that different carboxyl anions in the small peptoids of the Sil-peptoids had vast differences in their stereo-selectivity. The stereo-selectivity and the influence of Sil-peptoids on the retention behavior of complex drugs and their interaction mechanism for the drug molecules were effectively evaluated through the combination of chromatographic analysis and molecular modeling. Finally, a mixture of drugs consisting of two polar and six non-polar drugs was used to obtain a separation effect with a resolution >1.5. Two other groups of polar antibiotics were used to verify the separation ability of the Sil-peptoids. The results indicated that the Sil-peptoids could separate multiple substances simultaneously. These novel stationary phases can be applied to the analysis of complex multi-component drugs.

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Oral insulin therapies targeting the liver and further simulating close-looped secretion face significant challenges due to multiple trans-epithelial barriers. Herein, ursodeoxycholic acid (UDCA)-decorated zwitterionic nanoparticles (NPs) (UC-CMs@ins) are designed to overcome these barriers, target the liver, and respond to glycemia, thereby achieving oral one-time-per-day therapy. UC-CMs@ins show excellent mucus permeability through the introduction of zwitterion (carboxy betaine, CB). Furthermore, UC-CMs@ins possess superior cellular internalization via proton-assisted amino acid transporter 1 (PAT1, CB-receptor) and apical sodium-dependent bile acid transporter (ASBT, UDCA-receptor) pathways. Moreover, UC-CMs@ins exhibit excellent endolysosomal escape ability and improve the basolateral release of insulin into the bloodstream via the ileal bile acid-binding protein and the heteromeric organic solute transporter (OSTα- OSTß) routes compared with non-UDCA-decorated C-CMs@ins. Therefore, CB and UDCA jointly overcome mucus and intestinal barriers. Additionally, UC-CMs@ins prevent insulin degradation in the gastrointestinal tract for crosslinked structure, improve insulin accumulation in the liver for UDCA introduction, and effectively regulate glycemia for "closed-loop" glucose control. Surprisingly, oral ingestion of UC-CMs@ins shows a superior effect on glycemia (≈22 h, normoglycemia) and improves postprandial glycemic levels in diabetic mice, illustrating the enormous potential of the prepared NPs as a platform for oral insulin administration in diabetes treatment.

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The reactions of 2,4-di-tert-butyl-6-(diphenylphosphino)phenol and various Michael acceptors (acrylonitrile, acrylamide, methyl vinyl ketone, several acrylates, methyl vinyl sulfone) yield the respective phosphonium phenolate zwitterions at room temperature. Nine different zwitterions were synthesized and fully characterized. Zwitterions with the poor Michael acceptors methyl methacrylate and methyl crotonate formed, but could not be isolated in pure form. The solid-state structures of two phosphonium phenolate molecules were determined by single-crystal X-ray crystallography. The bonding situation in the solid state together with NMR data suggests an important contribution of an ylidic resonance structure in these molecules. The phosphonium phenolates are characterized by UV-vis absorptions peaking around 360 nm and exhibit a negative solvatochromism. An analysis of the kinetics of the zwitterion formation was performed for three Michael acceptors (acrylonitrile, methyl acrylate, and acrylamide) in two different solvents (chloroform and methanol). The results revealed the proton transfer step necessary to stabilize the initially formed carbanion as the rate-determining step. A preorganization of the carbonyl bearing Michael acceptors allowed for reasonable fast direct proton transfer from the phenol in aprotic solvents. In contrast, acrylonitrile, not capable of forming a similar preorganization, is hardly reactive in chloroform solution, while in methanol the corresponding phosphonium phenolate is formed.