Localized electrodeposition micro additive manufacturing of pure copper microstructures

The fabrication of pure copper microstructures with submicron resolution has found a host of applications,such as 5G communications and highly sensitive detection.The tiny and complex features of these structures can enhance device performance during high-frequency operation.However,manufacturing pure copper microstructures remain challenging.In this paper,we present localized electrochemical deposition micro additive manufacturing(LECD-μAM).This method combines localized electrochemical deposition(LECD)and closed-loop control of atomic force servo technology,which can effectively print helical springs and hollow tubes.We further demonstrate an overall model based on pulsed microfluidics from a hollow cantilever LECD process and closed-loop control of an atomic force servo.The printing state of the micro-helical springs can be assessed by simultaneously detecting the Z-axis displacement and the deflection of the atomic force probe cantilever.The results showed that it took 361 s to print a helical spring with a wire length of 320.11μm at a deposition rate of 0.887μm s^(-1),which can be changed on the fly by simply tuning the extrusion pressure and the applied voltage.Moreover,the in situ nanoindenter was used to measure the compressive mechanical properties of the helical spring.The shear modulus of the helical spring material was about 60.8 GPa,much higher than that of bulk copper(~44.2 GPa).Additionally,the microscopic morphology and chemical composition of the spring were characterized.These results delineate a new way of fabricating terahertz transmitter components and micro-helical antennas with LECD-μAM technology.

Effect of Plastocene Embedment in the Microperforated Plate on Its AcousticPerformance

Noise pollution is one of the contemporary environmental pollution, which seriously damages people’s green andhealthy life. In order to further improve the low frequency sound absorption performance of microperforatedpanel (MPP), a new plastocene coupled microperforated plate (PCMPP) is proposed. The acoustic propertiesof PCMPP with different apertures and perforation ratio were measured by transfer function method and compared with that of conventional MPPs. It is found that when the aperture was 0.8 mm, the peak value of soundabsorption coefficient of PCMPP decreased by 150 Hz compared with MPP. In a certain range, PCMPP with larger apertures showed a greater influence on sound absorption property in low frequency. In addition, higher perforation ratio led to a greater PCMPP bandwidth of sound absorption. On the other hand, the effect of PCMPPwith aperture of 0.2 mm on the performance of MPP was reduced, which could be compensated by increasing theperforation ratio. Furthermore, we found that the effect of aperture, perforation ratio and cavity on the soundabsorption performance of PCMPP was consistent with that of ideal rigid MPP. The step cooling curve showedthat the plastocene began to soften at about 50℃, representing a great potential for a non-high temperaturework environment.

Ligand engineering of colloid quantum dots and their application in all-inorganic tandem solar cells

How to effectively utilize the energy of the broad spectrum of sunlight is one of the basic problems in the research of tandem solar cells. Due to their size effect, quantum confinement effect and coupling effect, colloidal quantum dots(QDs) exhibit new physical properties that bulk materials don’t possess.CdX(X = Se, S, etc.) and Pb X(X = Se, S, etc.) QDs prepared by hot-injection methods have been widely studied in the areas of photovolitaic devices. However, the surfactants surrounding QDs seriously hinder the charge transport of QDs based solar cells. Therefore, how to fabricate high-performance tandem solar cells via ligands engineering has become a major challenge. In this paper, the latest progress of colloidal QDs in the research of all-inorganic tandem solar cells was summarized. Firstly, the improvement of QDs surface ligands and the optimization of ligands engineering were discussed, and the control of the physical properties of QDs films were realized. From the aspects of colloidal QDs, ligand engineering, and solar cell preparation, the future development direction of colloidal QDs solar cells was proposed, providing technical guidances for the preparation of low-cost and high-efficiency nanocrystalline solar cells.

Recent progress in bio-inspired macrostructure array materials with special wettability—from surface engineering to functional applications

Bio-inspired macrostructure array(MAA,size:submillimeter to millimeter scale)materials with special wettability(MAAMs-SW)have attracted significant research attention due to their outstanding performance in many applications,including oil repellency,liquid/droplet manipulation,anti-icing,heat transfer,water collection,and oil–water separation.In this review,we focus on recent developments in the theory,design,fabrication,and application of bio-inspired MAAMs-SW.We first review the history of the basic theory of special wettability and discuss representative structures and corresponding functions of some biological surfaces,thus setting the stage for the design and fabrication of bio-inspired MAAMs-SW.We then summarize the fabrication methods of special wetting MAAs in terms of three categories:additive manufacturing,subtractive manufacturing,and formative manufacturing,as well as their diverse functional applications,providing insights into the development of these MAAMs-SW.Finally,the challenges and directions of future research on bio-inspired MAAMs-SW are briefy addressed.Worldwide efforts,progress,and breakthroughs from surface engineering to functional applications elaborated herein will promote the practical application of bio-inspired MAAMs-SW.

HG-Induced sEVs Mediate Biomechanics of HK-2 Cells

Small extracellular vesicles (sEVs) participate in the pathological progression of high glucose (HG)-induced kidney injury, which is closely related to diabetic nephropathy. How sEVs specifically mediate the cell biomechanics underlying HG injury is unclear. Herein, we utilized a versatile atomic force microscope to determine the contributions of sEVs in HG-induced cellular injury. The sEVs extracted from the culture medium of human proximal tubule kidney (HK-2) cells treated by HG for 72 h (HG-induced sEVs) were verified and analyzed by multiple techniques, and the results indicated the effective production and the effect of dehydration on the shape of HG-induced sEVs. Further investigation on the morphologies of HK-2 cells treated by HG-induced sEVs showed that the surface roughness of the HK-2 cells increased, and their pseudopodia transitioned from lamellipodia to filopodia, with almost doubled mean pseudopodia length. Quantitative analysis of the mechanical responses of the cells revealed that the mean Young’s modulus increased by 26.2%, and the mean adhesion decreased by 36.8%. The indirect mediation of cellular biomechanics guided by HG-induced sEVs was evaluated by comparing it with previously studied direct HG injury. The HG-induced sEVs caused a greater reduction in cell adhesion and an increase in Young’s modulus compared with direct HG stimulation. This work suggested the ability of HG-induced sEVs to elicit specific biomechanical responses during HG injury, advancing the understanding of the injury mechanism caused by HG. The comparison of the cellular biomechanics between direct and indirect HG stimulations through HG-induced sEVs can be beneficial for the diagnosis and treatment of kidney injury.

Effect of Probe Lifting Height in Jumping Mode AFM for Living Cell Imaging

Atomic force microscopy(AFM)is one of the effective methods for imaging the morphological and physical properties of living cells in a near-physiological environment.However,several problems caused by the adhesion of living cells and extension of the cell membranes seriously affect the image quality during living cell imaging,hindering the study of living cells.In this work,jumping mode AFM imaging was used to image living cells at varied probe lifting heights to meet image quality requirements,and image quality related to the probe lifting height is discussed in detail.The jumping mode was divided into three parts based on the varying heights of the lifted probe,namely near-contact mode,half-jumping mode,and full-jumping mode,and the causes of their imaging drawbacks were analyzed.At an appropriate lifting height,the probe can be completely free from the influence of cell adhesion and self-excited oscillation,thus avoiding the occurrence of“trail”phenomena and invalid points in the imaging of living cells and improving the image quality.Additionally,this work provides a new approach to calculating the lateral force through the adhesion of trace and retrace scanning at a low height,which is important for studying the extension characteristics of the cell membrane.

Novel Hollow Re-entrant Structures Improving Hydrophobicity of Metal Surfaces

Re-entrant structures have drawn increasing attention because of their hydrophobicity.However,it is very difficult to manufacture re-entrant structures at the micron scale on metal surfaces.In this study,we designed and manufactured novel hollow re-entrant structures employing laser ablation and electrodeposition technology.This designed hollow re-entrant structure on metal surfaces has been fabricated successfully,which has high processing efficiency and good repeatability.The morphology and size of the hollow re-entrant structures were characterized.We found that the hydrophobic performance of hollow re-entrant structures was improved after being in the atmosphere for 3 days.After electrodeposition,the static contact angle was 133°.However,after being placed in the atmosphere for 3 days,the static contact angle was 140.4°,which is 5.2%higher than that after electrochemical deposition.We explained the cause of this phenomenon.The change of element content on the surface of hollow re-entrant structures was used to indicate the formation of metal oxide.After being in the atmosphere for 3 days,oxygen content increased by 0.4%.The metal surfaces with hollow re-entrant structures have a broader application prospect.

Biomimetic Superlyophobic Metallic Surfaces: Focusing on Their Fabrication and Applications

Metals are indispensable engineered materials for day-to-day life.Researches focused on metallic surfaces with superlyophobicity(superhydrophobicity,superoleophobicity,underwater superoleophobicity and slippery characteristic)have attracted much attention recently.Nature is a magician that gives each organic life a unique advantage.Researchers have created a large number of biomimetic superlyophobic metallic surfaces through various approaches.These biomimetic superlyophobic metallic surfaces exhibit advantages in many applications,such as self-cleaning,corrosion resistance,anti-icing,and drag reduction.In this review,the specific fabrication and applications of biomimetic superlyophobic metallic surfaces were reported.The remaining challenges and future outlook of biomimetic superlyophobic metallic surfaces were preliminarily analyzed.It is hoped that the review will be essential for broadening the scope of potential applications of metals and providing a powerful reference for future research on metal-based advanced functional materials.

Magnetic Ganoderma Lucidum Spores(mGLS):A Novel Regulatable Targeted Drug Delivery System

In the past decades,many materials have been studied as carriers for targeted drug delivery.However,there is a need for utilizable and selective carrier materials with few side effects.Here,the magnetic Ganoderma Lucidum Spores(mGLS)as a highly efficient targeted drug delivery carrier were explored.Then the regulatable targeted drug delivery system was verified by loading and releasing of the 5-Fluorouracil(5-FU).The results showed that the maximum of the loaded 5-FU reached 250.23 mg·g^(−1)in the mGLS.The cumulative release of the 5-FU for the drug delivery system could reach 80.11%and 67.14%in the PBS and HCl after 48 h,respectively.In addition,this system showed the good pharmacokinetic properties in vivo.After 12 h,the blood concentration in the 5-FU@mGLS group kept at 5.3µg·mL^(−1)and was four times higher than that in the 5-FU group.In summary,the GLS as a natural microscale core-shell structures appears the striking application in carrier material for oral drug delivery.