Understanding the Seeded Heteroepitaxial Growth of Crystallizable Polymers: The Role of Crystallization Thermodynamics.

Seeded heteroepitaxial growth is a "living" crystallization-driven self-assembly (CDSA) method that has emerged as a promising route to create uniform segmented nanoparticles with diverse core chemistries by using chemically distinct core-forming polymers. Our previous results have demonstrated that crystallization kinetics is a key factor that determines the occurrence of heteroepitaxial growth, but an in-depth understanding of controlling heteroepitaxy from the perspective of crystallization thermodynamics is yet unknown. Herein, we select crystallizable aliphatic polycarbonates (PxCs) with a different number of methylene groups (xCH2, x = 4, 6, 7, 12) in their repeating units as model polymers to explore the effect of lattice match and core compatibility on the seeded growth behavior. Seeded growth of PxCs-containing homopolymer/block copolymer blend unimers from poly(ε-caprolactone) (PCL) core-forming seed platelet micelles exhibits distinct crystal growth behavior at subambient temperatures, which is governed by the lattice match and core compatibility. A case of seeded growth with better core compatibility and a smaller lattice mismatch follows epitaxial growth, where the newly created crystal domain has the same structural orientation as the original platelet substrate. In contrast, a case of seeded growth with better core compatibility but a larger lattice mismatch shows nonepitaxial growth with less-defined crystal orientations in the platelet plane. Additionally, a case of seeded growth with poor core compatibility and larger lattice mismatch results in polydisperse platelet micelles, whereby crystal formation is not nucleated from the crystalline substrate. These findings reveal important factors that govern the specific crystal growth during a seeded growth approach by using compositionally distinct cores, which would further guide researchers in designing 2D segmented materials via polymer crystallization approaches.

Uniform Two-Dimensional Crystalline Platelets with Tailored Compositions for pH Stimulus-Responsive Drug Release.

Two-dimensional, size-tunable, water-dispersible particle micelles with spatially defined chemistries can be obtained by using "living" crystallization-driven self-assembly (CDSA) approach. Nevertheless, a major obstacle of crystalline particles in drug delivery application is the difficulty in accessing to cargo within crystalline cores. In the present work, we design four different types of biocompatible two-dimensional platelets with a crystalline poly(ε-caprolactone) (PCL) core, a hydrophobic poly(4-vinylprydine) (P4VP) segment, and a water dispersible poly(N,N-dimethyl acrylamide) (PDMA) block in ethanol by seeded growth method. Transferring those uniform platelets with tailored compositions to an aqueous solution in the presence of a hydrophobic drug leads to efficient encapsulation of the cargo in the P4VP segments via hydrophobic interactions. These drug-loaded platelets exhibit pH-responsive release behavior in aqueous media due to the protonated-deprotonated process of P4VP blocks in acidic and neutral solutions. This work provides initial insight into biocompatible PCL platelets with low dispersity and precise chemistry control in stimulus-responsive drug delivery fields.

Identification and Validation of Glycosyltransferases Correlated with Cuproptosis as a Prognostic Model for Colon Adenocarcinoma.

Cuproptosis is a newly defined programmed cell death pattern and is believed to play an important role in tumorigenesis and progression. In addition, many studies have shown that glycosylation modification is of vital importance in tumor progression. However, it remains unclear whether glycosyltransferases, the most critical enzymes involved in glycosylation modification, are associated with cuproptosis. In this study, we used bioinformatic methods to construct a signature of cuproptosis-related glycosyltransferases to predict the prognosis of colon adenocarcinoma patients. We found that cuproptosis was highly correlated with four glycosyltransferases in COAD, and our model predicted the prognosis of COAD patients. Further analysis of related functions revealed the possibility that cuproptosis-related glycosyltransferase Exostosin-like 2 (EXTL2) participated in tumor immunity.

[Study on the hemodynamic changes in solid thyroid nodules by ultrasound contrast quantitative analysis].

OBJECTIVE: To compare the difference between the different perfusional regions in solid thyroid nodules. METHODS: From October 2013 to May 2015, CEUS was performed in 59 patients who hospitalizated in Zhoushan Hospital with solid thyroid nodules before operation. The time-intensity curve (TIC) of normal thyroid tissue, tumor edge and tumor center was drawn to collect perfusion index like the peak intensity (PI), time to peak (TP), area under the curve (AUC), mean transit time (MTT). After surgery, immunohistochemical staining was performed to evaluate the MVD in surgical specimens.Quantitative parameters and MVD were assessed by the Spearman correlation analysis. RESULTS: There were 31 thyroid papillary carcinomas and 28 nodular goiters. In malignant tumor group, the PI of normal thyroid tissue, tumor edge and tumor center were 28% ± 6%, 21% ± 7% and 14% ± 5%, respectively, while the AUC and MVD of the same regions were (1 865 ± 1 079)%S, (1 376 ± 595)%S, (805 ± 412)%S and(33 ± 6), (27 ± 6)/HP, (17 ± 6)/HP, respectively. The differences were statistically significant. However, in benign tumor group, there was no obvious statistic difference in the quantitative parameters and MVD between the three regions. The PI values of thyroid carcinomas and nodular goiters all were positively correlated with MVD (r=0.819, r=0.838, P<0.05). CONCLUSIONS: The variance of perfusion parameters were valuable diagnostic basis in differential diagnosis between benign and malignant thyroid nodules. They were associated with MVD, which might reflect the microvessel distributional characteristics of neoplasm and might be one of bases used to evaluate neoplasm angiogenesis.