In vitro 3D malignant melanoma model for the evaluation of hypericin-loaded oil-in-water microemulsion in photodynamic therapy

Advances in biomimetic three-dimensional(3D) melanoma models have brought new prospects of drug screening and disease modeling, since their physiological relevancy for recapitulating in vivo tumor architectures is more accurate than traditional two-dimensional(2D) cell culture. Gelatin methacryloyl(GelMA) is widely used as a tissue-engineered scaffold hydrogel for 3D cell culture. In the present study, an in vitro 3D malignant melanoma model based on Gel MA was fabricated to evaluate the efficiency of hypericin(Hy)-loaded microemulsion(ME) in photodynamic therapy against melanoma. The ME was produced by the spontaneous emulsification method to enhance the bioavailability of Hy at tumor sites. Hy-loaded MEs were applied to a 3D malignant melanoma model made using 6% Gel MA and the co-culture of B16F10 and Balb/c 3T3 cells,followed by crosslinking using violet light(403 nm). The observation revealed excellent cell viability and the presence of F-actin cytoskeleton network. Hy-loaded MEs exhibited higher phototoxicity and cell accumulation(about threefold) than free Hy, and the cells cultured in the 3D system displayed lower susceptibility(about 2.5-fold) than those in 2D culture.These findings indicate that the developed MEs are potential delivery carriers for Hy;furthermore, Gel MA hydrogel-based modeling in polydimethylsiloxane(PDMS) molds is a user-friendly and cost-effective in vitro platform to investigate drug penetration and provide a basis for evaluating nanocarrier efficiency for skin cancer and other skin-related diseases.

3D human nonalcoholic hepatic steatosis and fibrosis models

This study presents a simple and robust three-dimensional human hepatic tissue model to emulate steatotic and fibrotic conditions and provide an in vitro model for drug testing and mechanistic studies.Using a photolithographic biofabrication method with a photomask featuring hexagonal units,liver cells,including a human hepatic cell line(HepG2-C3A)and a human hepatic stellate cell line(LX-2)were embedded in gelatin methacryloyl hydrogel.Hepatic steatosis was induced by supraphysiological concentration of free fatty acids;hepatic fibrosis was induced by transforming growth factor-β1.Induction of steatosis was confirmed by Oil Red O and BODIPY staining and was inhibited with toyocamycin and obeticholic acid.Induction of fibrosis was confirmed by immunostaining for collagen type I and alpha smooth muscle actin and inhibited by rapamycin and curcumin treatment.This model was further preliminarily validated using primary human hepatocytes in a similar setup.These constructs provide a viable,biologically relevant,and higher throughput model of hepatic steatosis and fibrosis and may facilitate the study of the mechanisms of disease and testing of liver-directed drugs.

3D-bioprinted cholangiocarcinoma-on-a-chip model for evaluating drug responses

Cholangiocarcinoma(CCA)is characterized by heterogeneous mutations and a refractory nature.Thus,the development of a model for effective drug screening is urgently needed.As the established therapeutic testing models for CCA are often ineffective,we fabricated an enabling three-dimensional(3D)-bioprinted CCA-on-a-chip model that to a good extent resembled the multicellular microenvironment and the anatomical microstructure of the hepato-vascular-biliary system to perform high-content antitumor drug screening.Specifically,cholangiocytes,hepatocytes,and vascular endotheliocytes were employed for 3D bioprinting of the models,allowing for a high degree of spatial and tube-like microstructural control.Interestingly,it was possible to observe CCA cells attached to the surfaces of the gelatin methacryloyl(GelMA)hydrogelembedded microchannels and overgrown in a thickening manner,generating bile duct stenosis,which was expected to be analogous to the in vivo configuration.Over 4000 differentially expressed genes were detected in the CCA cells in our 3D coculture model compared to the traditional two-dimensional(2D)monoculture.Further screening revealed that the CCA cells grown in the 3D traditional model were more sensitive to the antitumoral prodrug than those in the 2D monoculture due to drug biotransformation by the neighboring functional hepatocytes.This study provides proof-of-concept validation of our bioprinted CCA-on-a-chip as a promising drug screening model for CCA treatment and paves the way for potential personalized medicine strategies for CCA patients in the future.

差序格局是一种国家内文化吗?——中国地区差序文化的指标开发与验证、异质性分布及其影响

“差序格局”是中国社会科学应用最广、影响力最大的本土概念,但主流研究大多将它视为中国社会泛在性的文化特征,隐含假定它在中国各地区(例如省份)之间是同质的。对此,本文基于文化演化视角,探索差序文化省际异质性的存在性,以及这种异质性与当代省际不平衡发展的内在联系。在实证阶段,在开发出省际差序文化测量方法的基础上,对研究假设开展检验。研究发现:第一,差序文化在中国内部呈现出以“局部趋同,整体趋异”为特征的省际异质性;第二,这种异质性对于理解省际不平衡发展是重要的,它广泛解释了各省在政治、经济、社会和技术方面的发展差异。本文率先为差序文化的地区异质性提供了理论解释、经验证据和方法论工具,对于推动面向实证的差序格局研究具有重要价值。

A Novel Frequency Selective Surface with Improved Miniaturization Performance

Based on previous work, a novel Frequency Selective Surface (FSS) consisting of two metallic layers is proposed. The first layer is inductive-designed to generate the band-pass performance, while the second layer is capacitive-designed so that the miniaturization characteristic can be further improved. As a result, compared with the traditional single-layer structure, the profile of the FSS proposed is relatively small with the cell’s dimension only 0.0814λ × 0.0814λ. Moreover, the structure’s stability corresponding to waves of different polarizations and incident angles are also testified, which ensures the practicability of the proposed structure.

Inorganic matter in rice husk derived carbon and its effect on the capacitive performance

Porous carbons were obtained from rice husk using two different chemical activation methods and they were investigated as supercapacitors.Their properties were studied using X-ray photoelectron spectroscopy,thermal analysis,potentiometric titration,and nitrogen adsorption isotherm.The specific capacitance measured in both H_(2) SO_(4) and KOH electrolytes in two-electrode cell was up to-150 F/g.The activation method used affected the resulting carbons’features.As expected,the dependence of the capacitance on porosity was found.The ash content reached 36 wt.%and that inorganic mater blocked some pores and limited their accessibility to electrolyte ions and increased the charge transfer resistance.Nevertheless,the main ash constituents such as CaCO_(3),MgCO_(3),Ca_(3)(PO_(4))2(or P_(2)O_(5)),and Fe-and Zn-containing species did not affect the specific capacitance to a large extent.Especially SiO2,even in a relatively large amount(~20 wt.%)T did not play a detrimental role in the capacitance behavior.The results showed that in spite of a high ash content,carbon can exhibit a good capacitive performance provided that it has a favorable porosity and is rich in sp_(2) configurations.

Digital light processing (DLP)-based (bio)printing strategies for tissue modeling and regeneration

Digital light processing(DLP)-based bioprinting technology has recently aroused considerable concerns as a strategy to deliver biomedical materials and/or specific cells to create sophisticated structures for various tissue modeling and regeneration.In this review,we display a concise introduction of DLP bioprinting,and a further discussion on the design and manufacture of DLP(bio)printer with varied bioinks and their biomedical applications toward drug screening,disease modeling,tissue repair,and regenerative medicine.Finally,the advantages,challenges,and perspectives of the DLP printing platforms are detailed.It is believed that DLP bioprinting will play a decisive role in the field of tissue model and regenerative medicine,mainly due to its time-efficient,higher resolution,and amenability to automation for various tissue needs.

Superwettable interface towards biodetection in confined space

The detection of biomarkers with both high sensitivity and specificity is crucial for the diagnosis and treatment of related diseases.However,many current detections employ ex-situ detection method and non-confined condition,thus have many problems,which may eventually lead to inaccurate detection results.Compared to detection in non-confined space,detection in confined space can better reflect the real in-vivo situation.Therefore,the construction of detection for target molecules in confined space has great significance for both theoretical research and practical application.To realize the detection of target molecules in confined space,the probes should accurately enter the confined space where the target molecules reside and interact with the interface.Thus,how to explore and utilize the properties of the interface(for example,bioinspired superwettability)has always been a hot and difficult topic in this field.Herein,the recent advances and our efforts in recent 10 years on detection of bio-target molecules in confined space with superwettable interface have been introduced from the perspective of the detection methods.The suitable and most widely employed detection methods for target molecules in confined spaces are introduced firstly.Then,recent progresses for related detections based on visual,optical,and electrochemical detection methods are presented successively.Finally,the perspective for detection in confined space is discussed for the future development of biochemical detection.

Biosynthesis of trialkyl-substituted aromatic polyketide NFAT-133 involves unusual P450 monooxygenase-mediating aromatization and a putative metallo-beta-lactamase fold hydrolase

The bacterial trialkyl-substituted aromatic polyketides are structurally featured with the unusual aromatic core in the middle of polyketide chain such as TM-123(1),veramycin A(2),NFAT-133(3)and benwamycin I(4),which were discovered from Streptomyces species and demonstrated with antidiabetic and immunosuppressant activities.Though the biosynthetic pathway of 1-3 was reported as a type I polyketide synthase(PKS),the PKS assembly line was interpreted inconsistently,and it remains a mystery how the compound 3 was generated.Herein,the PKS assembly logic of 1-4 was revised by site-mutagenetic analysis of the PKS dehydratase domains.Based on gene deletion and complementation,the putative P450 monooxygenase nftE1 and metallo-beta-lactamase(MBL)fold hydrolase nftF1 were verified as essential genes for the biosynthesis of 1-4.The absence of nftE1 led to abolishment of 1-4 and accumulation of new products(5-8).Structural elucidation reveals 5-8 as the non-aromatic analogs of 1,suggesting the NftE1-catalyzed aromatic core formation.Deletion of nftF1 resulted in disappearance of 3 and 4 with the compounds 1 and 2 unaffected.As a rare MBL-fold hydrolase from type I PKSs,NftF1 potentially generates the compound 3 through two strategies:catalyze premature chain-offloading as a trans-acting thioesterase or hydrolyze the lactone-bond of compound 1 as an esterase.

Investigation of carbonyl amidation and O-methylation during biosynthesis of the pharmacophore pyridyl of antitumor piericidins

Piericidins are a large family of bacterialα-pyridone antibiotics with antitumor activities such as their anti-renal carcinoma activity exhibited recently in nude mice.The backbones of piericidins are derived fromβ,δ-diketo carboxylic acids,which are offloaded from a modular polyketide synthase(PKS)and putatively undergo a carbonyl amidation beforeα-pyridone ring formation.The tailoring modifications to theα-pyridone structure mainly include the verified hydroxylation and O-methylation of the C-4′position and an unidentified C-5′O-methylation.Here,we describe a piericidin producer,terrestrial Streptomyces conglobatus,which contains a piericidin biosynthetic gene cluster in two different loci.Deletion of the amidotransferase gene pieD resulted in the accumulation of two fatty acids that should be degraded from the nascent carboxylic acid released by the PKS,supporting the carbonyl amidation function of PieD duringα-pyridone ring formation.Deletion of the O-methyltransferase gene pieB1 led to the production of three piericidin analogues lacking C-5′O-methylation,therefore confirming that PieB1 specifically catalyses the tailoring modification.Moreover,bioactivity analysis of the mutant-derived products provided clues regarding the structure-function relationship for antitumor activity.The work addresses two previously unidentified steps involved in pyridyl pharmacophore formation during piericidin biosynthesis,facilitating the rational bioengineering of the biosynthetic pathway towards valuable antitumor agents.