RESUMO
Tyrosine kinase inhibitors (TKIs) have revolutionized the treatment landscape for chronic myeloid leukemia (CML). However, TKI resistance poses a significant challenge, leading to treatment failure and disease progression. Resistance mechanisms include both BCR::ABL1-dependent and BCR::ABL1-independent pathways. The mechanisms underlying BCR::ABL1 independence remain incompletely understood, with CML cells potentially activating alternative signaling pathways, including the AKT/mTOR and JAK2/STAT5 pathways, to compensate for the loss of BCR::ABL1 kinase activity. This study explored tumoral VISTA (encoded by VSIR) as a contributing factor to TKI resistance in CML patients and identified elevated tumoral VISTA levels as a marker of resistance and poor survival. Through in vitro and in vivo analyses, we demonstrated that VSIR knockdown and the application of NSC-622608, a novel VISTA inhibitor, significantly impeded CML cell proliferation and induced apoptosis by attenuating the AKT/ mTOR and JAK2/STAT5 pathways, which are crucial for CML cell survival independent of BCR::ABL1 kinase activity. Moreover, VSIR overexpression promoted TKI resistance in CML cells. Importantly, the synergistic effect of NSC-622608 with TKIs offers a potent therapeutic avenue against both imatinib-sensitive and imatinib-resistant CML cells, including those harboring the challenging T315I mutation. Our findings highlight the role of tumoral VISTA in mediating TKI resistance in CML, suggesting that inhibition of VISTA, particularly in combination with TKIs, is an innovative approach to enhancing treatment outcomes in CML patients, irrespective of BCR::ABL1 mutation status. This study not only identified a new pathway contributing to TKI resistance but also revealed the possibility of targeting tumoral VISTA as a means of overcoming this significant clinical challenge.
RESUMO
Chiral plasmonic nanostructures exhibit potential in the advanced manufacturing industry, due to their fascinating characteristics. However, the limitation of existing fabrication methods as difficulty to precisely manipulate chiral nanostructures at the nanoscale restricts their application and optimization of performance. In this work, we report a simple and robust route for the precise construction of chiral Au nanoparticles (NPs), employing star-like block copolymers with well-defined structures as chiral templates. The globular unimolecular micelles as nanoreactors enabled control over the size, shape, and chirality of in situ grown nanocrystals. Utilizing the chiral anisotropy property of surface-enhanced Raman scattering (SERS), the enantioselective discrimination on various substrates was accomplished with an enhancement factor over 9.3 × 106. NPs with a smaller size exhibited strengthened Raman enhancement and chiral recognition. Furthermore, these chiral unimolecular-micelle-based templates with high efficiency and strong controllability could pave the way for tailor-made chiral nanomaterials.
RESUMO
Azobenzene (Azo) liquid-crystalline polymers are intriguing due to their unique photo-induced isomerization and supramolecular chirality. However, clarification on multicomponent chiral induction towards Azo polymers remains ambiguous and challenging. Herein, chiral solvents and amines were employed to control the chiroptical activity of achiral Azo polymers. Methyl L-/D-lactate was added as the poor solvent and chiral inducer to achieve the first chiral induction in Azo aggregates. Chiral amines were utilized for the second chiral induction based on the acid-base interactions between the carboxyl groups of polymers and amines. The chiral enhancement and inversion of Azo units could be observed through the synergistic or antagonistic effect between solvents and amines. The impacts of solvent, chemical structures, feed ratio, enantiomeric excess, and temperature on supramolecular chirality were systematically studied. Furthermore, this system displayed the chiroptical switching property and chiral recovery under reversible irradiation.
Assuntos
Antígenos CD19 , Células Dendríticas , Imunoterapia Adotiva , Adulto , Humanos , Pessoa de Meia-Idade , Antígenos CD19/imunologia , Vacinas Anticâncer/uso terapêutico , Células Dendríticas/imunologia , Imunoterapia Adotiva/métodos , Leucemia-Linfoma Linfoblástico de Células Precursoras B/terapia , Leucemia-Linfoma Linfoblástico de Células Precursoras B/imunologia , Receptores de Antígenos Quiméricos/imunologia , Recidiva , Adulto Jovem , IdosoRESUMO
Compared with normal stimulus such as light and heat, ultrasonic possesses much deeper penetration into tissues and organs and has lower scattering in heterogeneous systems as a noninvasive stimulus. Reversible addition-fragmentation chain-transfer polymerization (RAFT) in aqueous media is performed in a commercial ultrasonic wash bath with 40 kHz frequency ultrasonic, in the presence of piezoelectric tetragonal BaTiO3 (BTO) nanoparticles. Owing to the electron transfer from BTO under the ultrasonic action, the water can be decomposed to produce hydroxyl radical (HOâ¢) and initiate the RAFT polymerization (piezo-RAFT). The piezo-RAFT polymerization exhibits features of controllable and livingness, such as linear increase of molar mass and narrow molar mass distributions (Mw/Mn < 1.20). Excellent temporal control of the polymerization and the chain fidelity of polymers are illustrated by "ON and OFF" experiment and chain extension, separately. Moreover, this ultrasonic-driven piezoelectric-induced RAFT polymerization in aqueous media can be directly used for the preparation of piezoelectric hydrogel which have potential application for stress sensor.
RESUMO
The exploration of pharmaceutically active agents and positron emission tomography (PET) tracers targeting CXCR4 has been a focal point in cancer research given its pivotal role in the development and progression of various cancers. While significant strides have been made in PET imaging with radiometal-labeled tracers, the landscape of 18F-labeled small molecule tracers remains relatively limited. Herein, we introduce a novel and promising derivative, [18F]SFB-AMD3465, as a targeted PET tracer for CXCR4. The compound was synthesized by modifying the pyridine ring of AMD3465, which was subsequently labeled with 18F using [18F]SFB. The study provides comprehensive insights into the design, synthesis, and biological evaluation of [18F]SFB-AMD3465. In vitro and in vivo assessments demonstrated the CXCR4-dependent, specific, and sensitive uptake of [18F]SFB-AMD3465 in the CXCR4-overexpressing 4T1 cell line and the corresponding xenograft-bearing mouse model. These findings contribute to bridging the gap in 18F-labeled PET tracers for CXCR4 and underscore the potential of [18F]SFB-AMD3465 as a PET radiotracer for in vivo CXCR4 imaging.
Assuntos
Radioisótopos de Flúor , Tomografia por Emissão de Pósitrons , Receptores CXCR4 , Animais , Receptores CXCR4/análise , Receptores CXCR4/metabolismo , Tomografia por Emissão de Pósitrons/métodos , Camundongos , Radioisótopos de Flúor/química , Feminino , Linhagem Celular Tumoral , Humanos , Piridinas/química , Piridinas/farmacocinética , Neoplasias da Mama/diagnóstico por imagem , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Compostos Radiofarmacêuticos/química , Compostos Radiofarmacêuticos/farmacocinética , Distribuição TecidualRESUMO
Ultrasmall fluorescent nanomaterials have been widely studied as novel fluorescent probes; however, these nanomaterials are prone to structural damage or aggregation, and the sensitivity and accuracy of most single emission fluorescence probes were very low. Therefore, the controlled synthesis of stable dual-emission ratiometric fluorescence ultrasmall assembly probes still remains a challenge. Herein, star-like polymer unimolecular micelles were utilized as a scaffold template to encapsulate fluorescent ultrasmall carbon quantum dots (CQDs) and gold nanoclusters (AuNCs) via the polymer template directed self-assembly strategy to obtain multiple-responsive ratiometric fluorescent assemblies. The assemblies were ultrastable, well-defined, and nearly monodispersed with controlled size, regular morphology, and pH- and thermal-responsiveness. The assemblies can be applied to realize rapid, sensitive, quantitative, and specific detection of Cu2+ and GSH. Moreover, the convenient rapid real-time detection was realized via the combination of the visualized paper-based sensor, and the multilevel information encryption was also achieved.
RESUMO
BACKGROUND: Chronic graft-versus-host disease (cGVHD) is an immune-related disorder that is the most common complication post-allogenic hematopoietic stem cell transplant. Corticosteroids with or without calcineurin inhibitors (CNIs) remain the mainstay of cGVHD treatment for first-line therapy. However, for many patients, cGVHD symptoms cannot be effectively managed and thus require second-line therapy. Currently, there is no approved treatment for second-line cGVHD treatment in China. In this study, belumosudil, a highly selective and potent rho-associated coiled-coil-containing protein kinase-2 inhibitor demonstrated to be effective for cGVHD in the United States and other Western countries, is investigated in patients with cGVHD in China for its overall benefit-risk balance. METHODS: This multicenter, open-label phase II study evaluated the safety, efficacy, and pharmacokinetics of oral belumosudil 200 mg once daily in cGVHD patients who had been treated with at least one line of systemic therapy in China. The primary endpoint was overall response rate (ORR); each individual patient's response was assessed by the investigator using the 2014 National Institutes of Health consensus criteria. Secondary endpoints were duration of response (DOR), time to response (TTR), changes in Lee Symptom Scale (LSS) score, organ response rate, corticosteroid dose change, CNI dose change, failure-free survival, time-to-next-treatment, overall survival, and safety. RESULTS: Thirty patients were enrolled in the study with a median follow-up time of 12.9 months. ORR was 73.3% (95% confidence interval: 54.1-87.7%) and all responders achieved partial response. Median DOR among responders was not reached and median TTR was 4.3 weeks (range: 3.9-48.1). Fifteen patients (50.0%) achieved clinically meaningful response in terms of reduction in LSS score by ≥ 7 points from baseline. Corticosteroid and CNI dose reductions were reported in 56.7% (17/30) and 35.0% (7/20) of patients, respectively. Most treatment-emergent adverse events (TEAEs) were mild to moderate in severity, with 11 patients (36.7%) experiencing grade ≥ 3 TEAEs. The most common grade ≥ 3 TEAE was pneumonia (n = 5, 16.7%). CONCLUSIONS: Belumosudil treatment demonstrated a favorable benefit-risk balance in treating cGVHD patients who previously have had standard corticosteroid therapy in China where approved second-line setting is absent. TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT04930562.
Assuntos
Síndrome de Bronquiolite Obliterante , Doença Enxerto-Hospedeiro , Humanos , Acetamidas , Corticosteroides/uso terapêutico , Doença CrônicaRESUMO
Multiple myeloma (MM) is a hematological malignancy that remains incurable, primarily due to the high likelihood of relapse or development of resistance to current treatments. To explore and discover new medications capable of overcoming drug resistance in MM, we conducted cell viability inhibition screens of 1504 FDA-approved drugs. Lomitapide, a cholesterol-lowering agent, was found to exhibit effective inhibition on bortezomib-resistant MM cells in vitro and in vivo. Our data also indicated that lomitapide decreases the permeability of the mitochondrial outer membrane and induces mitochondrial dysfunction in MM cells. Next, lomitapide treatment upregulated DRP1 and PINK1 expression levels, coupled with the mitochondrial translocation of Parkin, leading to MM cell mitophagy. Excessive mitophagy caused mitochondrial damage and dysfunction induced by lomitapide. Meanwhile, PARP14 was identified as a direct target of lomitapide by SPR-HPLC-MS, and we showed that DRP1-induced mitophagy was crucial in the anti-MM activity mediated by PARP14. Furthermore, PARP14 is overexpressed in MM patients, implying that it is a novel therapeutic target in MM. Collectively, our results demonstrate that DRP1-mediated mitophagy induced by PARP14 may be the cause for mitochondrial dysfunction and damage in response to lomitapide treatment.
Assuntos
Benzimidazóis , Doenças Mitocondriais , Mieloma Múltiplo , Humanos , Mitofagia , Mieloma Múltiplo/tratamento farmacológico , Mieloma Múltiplo/genética , Mieloma Múltiplo/metabolismo , Mitocôndrias/metabolismo , Recidiva Local de Neoplasia/patologia , Resistência a Medicamentos , Doenças Mitocondriais/metabolismo , Doenças Mitocondriais/patologia , Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/metabolismo , Poli(ADP-Ribose) Polimerases/metabolismoRESUMO
Semiconducting nanocrystals have attracted world-wide research interest in artificial photosynthesis due to their appealing properties and enticing potentials in converting solar energy into valuable chemicals. Compared to 0D nanoparticles, 1D nanorods afford long-distance charge carriers separation and extended charge carriers lifetime due to the release of quantum confinement in axial direction. Herein, stable CsPbBr3 nanorods of distinctive dimensions are crafted without altering their properties and morphology via grafting hydrophobic polystyrene (PS) chains through a post-synthesis ligand exchange process. The resulting PS-capped CsPbBr3 nanorods exhibit a series of enhanced stabilities against UV irradiation, elevated temperature, and polar solvent, making them promising candidates for photo-induced atom transfer radical polymerization (ATRP). Tailoring the surface chemistry and dimension of the PS-capped CsPbBr3 nanorods endows stable, but variable reaction kinetics in the photo-induced ATRP of methyl methacrylate. The trapping-detrapping process of photogenerated charge carriers lead to extended lifetime of charge carriers in lengthened CsPbBr3 nanorods, contributing to a facilitated reaction kinetics of photo-induced ATRP. Therefore, by leveraging such stable PS-capped CsPbBr3 nanorods, the effects of surface chemistry and charge carriers dynamics on its photocatalytic performance are scrutinized, providing fundamental understandings for designing next-generation efficient nanostructured photocatalyst in artificial photosynthesis and solar energy conversion.
RESUMO
Functional nanomaterials made by chiral induction have attracted extensive attention because of their intriguing characteristics and potential applications. However, the precise and controllable fabrication of chiral nanomaterials still remains challenging but is highly desired. In this study, chiral unimolecular micelles with different molecular weights and chiroptical activities were prepared by photoinduced atom transfer radical polymerization (photoATRP). Through nanoconfined growth, the chiral plasmonic nanoparticle assemblies with predesigned size and morphology were prepared using chiral unimolecular micelles as nanoreactors. The controllability over chiral assemblies and the size effect on chiroptical properties were also investigated. Furthermore, chiral complexes with absorption asymmetry and circularly polarized luminescence (glum = 4.25 × 10-4) were easily constructed via mixing of organic fluorescent molecules and chiral templates based on intermolecular hydrogen bonds. Such results indicated that our unimolecular-micelle-based templates enable the controllable preparation of both inorganic and organic chiral nanostructures with tailored dimensions, sizes, compositions, and optical activities.
RESUMO
Traditional transparent polymer nanocomposites combined with functional fluorescent inorganic nanofillers are promising for many advanced optical applications. However, the aggregation of the incorporated functional nanoparticles results in light scattering and will decrease the transparency of nanocomposites, which will restrain the application of the transparent nanocomposites. Herein, a robust synthesis strategy was proposed to modify upconversion nanoparticles (UCNPs) with polymethyl methacrylate (PMMA) to form UCNP@PMMA core@shell nanocomposites though metal-free photoinduced surface-initiated atom transfer radical polymerization (photo-SI-ATRP), and thus, the dispersity of UCNP@PMMA and the interface compatibility between the surface of UCNPs and the bulk PMMA matrix was greatly improved. The obtained PMMA nanocomposites possess high transparency and show strong upconversion photoluminescence properties, which promises great opportunities for application in 3D display and related optoelectronic fields. This strategy could also be applied to fabricate other kinds of functional transparent polymer nanocomposites with inorganic nanoparticles uniformly dispersed.
RESUMO
Chimeric antigen receptor (CAR)-T cell therapy revolutionized treatment for various hematologic malignances. However, limited studies were reported to compare the efficacy and safety of CAR-T and donor lymphocyte infusion (DLI) for patients with relapsed B-cell acute lymphoblastic leukemia (B-ALL) after hematopoietic stem cell transplantation (HSCT) comprehensively. We conducted a single-center, retrospective comparative study that consisted of 12 patients who were treated with DLI (control group) and 12 patients treated with donor-derived CD19 CAR-T cells (experimental group, 6 patients also received CD22 or CD123 CAR-T cells sequentially) with 3 overlaps. The event-free survival (EFS) of patients in experimental group was superior to that of the control group: 516 days versus 98 days (p = 0.0415). Compared with 7 of 12 patients treated with DLI suffered grades III-IV acute graft versus host disease (aGVHD), one grade III aGVHD developed in patients treated with CAR-T therapy. No significant difference in the incidence of infection was identified between these two groups. Most patients in the experimental group had only mild cytokine release syndrome and none developed neurotoxicity. The univariate analysis of patients in the experiment group revealed that earlier CAR-T therapy for post-transplantation relapse was associated with better EFS. There was no significant difference in EFS between patients treated with dual-target CAR-T with those with single CD19 CAR-T. In this study, our data supported that donor-derived CAR-T therapy is a safe and potentially effective treatment for relapsed B-ALL after HSCT and may be superior to DLI.
Assuntos
Doença Enxerto-Hospedeiro , Transplante de Células-Tronco Hematopoéticas , Receptores de Antígenos Quiméricos , Humanos , Estudos Retrospectivos , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Transplante Homólogo/efeitos adversos , Imunoterapia Adotiva/efeitos adversos , Doença Enxerto-Hospedeiro/etiologia , Doença Enxerto-Hospedeiro/terapia , Antígenos CD19 , LinfócitosRESUMO
The novel COVID-19 pneumonia caused by the SARS-CoV-2 virus poses a significant threat to human health. Scientists have made significant efforts to control this virus, consequently leading to the development of novel research methods. Traditional animal and 2D cell line models might not be suitable for large-scale applications in SARS-CoV-2 research owing to their limitations. As an emerging modelling method, organoids have been applied in the study of various diseases. Their advantages include their ability to closely mirror human physiology, ease of cultivation, low cost, and high reliability; thus, they are considered to be a suitable choice to further the research on SARS-CoV-2. During the course of various studies, SARS-CoV-2 was shown to infect a variety of organoid models, exhibiting changes similar to those observed in humans. This review summarises the various organoid models used in SARS-CoV-2 research, revealing the molecular mechanisms of viral infection and exploring the drug screening tests and vaccine research that have relied on organoid models, hence illustrating the role of organoids in remodelling SARS-CoV-2 research.
RESUMO
Highly ordered TiO2 nanotube arrays (TNTAs) and their heterostructure nanocomposites by structural engineering design were utilized as heterogeneous photocatalysts for highly efficient broadband photoinduced controlled radical polymerization (photoCRP), including photoATRP and PET-RAFT. Highly efficient broadband UV-visible light responsive photoCRP was achieved by combining the acceleration effects of electron transfer derived from the distinctive highly ordered nanotube structure of TNTAs and the localized surface plasmon resonance (LSPR) effect combined with the formation of the Schottky barrier via modification of Au nanoparticles. This polymerization system was capable to polymerize acrylate and methacrylate monomers with high conversion, "living" chain-ends, tightly regulated molecular weights, and outstanding temporal control properties. The heterogeneous nature of the photocatalysts enabled simple separation and effective reusability in subsequent polymerizations. These results highlight the modular design of highly efficient catalysts to optimize the controlled radical polymerization process.
RESUMO
Background: Myocyte enhancer factor 2D (MEF2D) is involved in the progression of various malignant tumors. However, its impact on B-cell acute lymphoblastic leukemia (B-ALL) has not been elucidated. Methods: In this study, the expression level of MEF2D in B-ALL patients was validated through the Gene Expression Omnibus (GEO) database and clinical specimens. MEF2D-knockdown B-ALL cell lines were constructed by lentivirus transfection, and the effects of MEF2D on the viability, apoptosis, cycle progression, and drug sensitivity of B-ALL cells were verified by Cell Counting Kit-8 (CCK-8) and flow cytometry (FCM). The effect of MEF2D on the proliferation of B-ALL cells in vivo was verified via the construction of a xenograft mouse model. The mechanism of MEF2D regulating B-ALL cells was explored by RNA sequencing analysis, quantitative reverse transcription polymerase chain reaction (qRT-PCR), western blotting, and immunohistochemical (IHC). Results: In this study, overexpression of MEF2D was observed in B-ALL patients and was remarkably correlated to disease progression in ALL patients. The knockdown of MEF2D expression suppressed cell viability, induced cell apoptosis, blockaded cell cycle progression, enhanced drug sensitivity of B-ALL cells in vitro, and reduced the tumor load in vivo. Furthermore, mechanistic studies revealed that MEF2D knockdown downregulated the expression of the phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K)-protein kinase B (AKT) signaling pathway. Conclusions: Our research demonstrated that MEF2D was markedly expressed in B-ALL. MEF2D knockdown inhibited cancer progression of B-ALL both in vitro and in vivo, which may be related to the downregulation of the PI3K-AKT signaling pathway. The data suggest that MEF2D plays a vital role in the process of tumorigenesis and may be a potential novel target for B-ALL therapy.
RESUMO
Epidermal growth factor receptor pathway substrate number 8 (EPS8) has been reported to be critical in mediating tumor progression. However, the molecular and biological consequences of EPS8 overexpression remain unclear. Here we evaluated whether EPS8 increased DNA damage repair in non-small-cell lung carcinoma (NSCLC) cells and the mechanism of EPS8-mediated DNA damage repair which influenced chemosensitivity. Serial studies of functional experiments revealed that EPS8 knockdown inhibited cell growth, induced cell-cycle arrest and increased cisplatin therapeutic effects on NSCLC. EPS8 was found to induce DNA damage repair via upregulation of phosphorylated-ATM and downregulation of the tumor suppressor p53 and G1 cell kinase inhibitor p21. Moreover, in conjunction with cisplatin, decreasing EPS8 protein levels further increased p53 protein level and inhibited ATM signaling. Transplanted tumor studies were also performed to demonstrate that EPS8 knockdown inhibited tumor growth and sensitized tumors to cisplatin treatment. In conclusion, we have described a novel molecular mechanism through which EPS8 is likely to be involved in cancer progression and chemoresistance via DNA damage repair, indicating that EPS8 expression may influence the response to chemotherapy. Therefore, targeting EPS8 may be a potential therapeutic approach for patients with NSCLC.
Assuntos
Antineoplásicos , Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , Humanos , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/patologia , Cisplatino/farmacologia , Cisplatino/uso terapêutico , Proteína Supressora de Tumor p53/genética , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patologia , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Dano ao DNA , Linhagem Celular Tumoral , Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismoRESUMO
BACKGROUND: Time to treatment (TTT) varies widely for patients with gastric cancer. We aimed to evaluate relationships between time to treatment, overall survival (OS), and other surgical outcomes in patients with stage I-III gastric cancer. METHODS: We identified patients with clinical stage I-III gastric cancer who underwent curative-intent gastrectomy within the National Cancer Database (2006-2015) and grouped them by treatment sequence: neoadjuvant chemotherapy or surgery upfront. We defined TTT as weeks from diagnosis to treatment initiation (neoadjuvant chemotherapy or definitive surgical procedure, respectively). Survival differences were assessed by Kaplan-Meier estimate, Cox proportional hazard regression, and log rank test. RESULTS: Among the 22,846 patients with stage I-III gastric cancer, most (56%) received surgery upfront. Median TTT was 5 weeks (IQR 4-7) and 6 weeks (IQR 3-9) for patients in the neoadjuvant and surgery upfront groups, respectively. In the neoadjuvant group, increasing TTT was significantly associated with increasing median OS up to TTT of 5 weeks, with no change in median OS when TTT was > 5 weeks. In the surgery group, increasing TTT was significantly associated with increasing median OS up to 6 weeks; however, increasing TTT between 14 and 21 weeks was associated with decreasing median OS. CONCLUSIONS: The relationship between time to treatment and survival outcomes is non-linear. Among patients who underwent surgery upfront, the relationship between time to treatment and OS was bimodal, suggesting that deferring definitive surgery, up to 14 weeks, is not associated with worse OS or oncologic outcomes. The relationship between time to treatment and overall survival among patients was bimodal, suggesting that deferring definitive surgery up to 14 weeks is not associated with worse OS.
Assuntos
Neoplasias Gástricas , Humanos , Neoplasias Gástricas/cirurgia , Estadiamento de Neoplasias , Terapia Neoadjuvante/métodos , Quimioterapia Adjuvante , Estimativa de Kaplan-Meier , Estudos RetrospectivosRESUMO
Multiple and two-way reversible shape memory polymers (M/2W-SMPs) are highly promising for many fields due to large deformation, lightweight, strong recovery stress, and fast response rates. Herein, a semi-crystalline block poly(urethane-urea-amide) elastomers (PUUAs) are prepared by the copolymerization of isocyanate-terminated polyurethane (OPU) and amino-terminated oligomeric polyamide-1212 (OPA). PUUAs, composed of OPA as stationary phase and PTMEG as reversible phase, exhibit excellent rigidity, flexibility, and resilience, and cPUUA-C7 -S25 exhibits the best tensile property with strength of 10.3 MPa and elongation at break of 360.2%. Besides, all the PUUAs possess two crystallization/melting temperatures and a glass transition temperature, which endow PUUAs with multiple and reversible two-way shape memory effect (M/2W-SME). Physically crosslinked PUUA-C0 -S25 exhibits excellent dual and triple shape memory, and micro chemically crosslinked cPUUA-C7 -S25 further shows quadruple shape memory behavior. Additionally, both PUUA-C0 -S25 and cPUUA-C7 -S25 have 2W-SME. Intriguingly, cPUUA-C7 -S25 can achieve a higher temperature (up to 165 °C) SME, which makes it suitable for more complex and changeable applications. Based on the advantages of M/2W-SME, a temperature-responsive application scenario where PUUAs can transform spontaneously among different shapes is designed. These unique M/2W-SME and high-temperature SME will enable the applications of high-temperature sensors, actuators, and aerospace equipment.
Assuntos
Elastômeros , Polímeros , Polímeros/química , Amidas , Ureia , Poliuretanos/químicaRESUMO
Targeting sustainable and eco-friendly polymer synthesis, we demonstrate here a synergistically catalyzed atom transfer radical polymerization (ATRP) induced and controlled by interplay between ball milling (BM) and piezoelectric nanoparticles (piezoNPs). BM-induced electron transfer can be achieved through piezoNPs deformation under impact force, serving as an external stimulus to mediate polymerization. The ppm level of copper loading is sufficient in fabrication of a polymer with well-defined molecular weight and low polydispersity. High-molecular-weight polymers ranging from 33 to 74 kDa were prepared successfully through DMSO-assisted grinding. Besides, its good performance on availability of water as liquid-assisted grinding additive, the recyclability of piezoNPs, and the formation of cross-linker-free composite resin make our ATRP approach a green and practical option alongside the existent heat-, electro-, and photo-induced methods.