Sacrificial Template Research Articles

Desalination RO reject brine as a novel-based porous geopolymer for phosphorus removal from contaminated media

Desalination reverse osmosis reject brine-based porous geopolymer (RO/GP) was produced and investigated as an improved adsorbent for phosphorus (P) removal from tainted seawater, brackish water, river water, and municipal wastewater effluent. The RO reject brine/geopolymer was produced by reacting metakaolin and fly ash with a Na-alkali activator and anhydrous RO brine as a sacrificial template. The influence of RO reject brine content on water absorption, porosity, mechanical, and structural properties were examined. The developed RO-based geopolymers exhibited the greatest porosity (58.3–84.2 % vol%), a significant ratio of open porosity to total porosity (67.7–92.1 %), and outstanding compression strength (3.6–10.4 MPa). The produced RO/GP structure has an adsorption capacity of 92.4 mg-P/g. The sequestration reaction of phosphorus by RO/GP is of pseudo-second-order kinetic behavior via Chi-squared (χ2), RMSE, and determination coefficient (R2) values. Regarding their agreement with Langmuir behavior, the phosphorus adsorption uptakes occur in homogeneous and monolayer states. The reaction is exothermic, spontaneous, and favorable. The RO/GP exhibits significant affinity for phosphorus co-existing with Cl−, Na+, SO42−, K+, HCO3−, and Ca2+. The RO/GP shows high safety during the adsorption investigation, with a total cost of 0.32 $/kg-P.

A MOF-Templated Double-Shelled Co3O4/NiCo2O4 Nanocomposite for Electrochemical Detection of Alfuzosin.

We developed a novel electrochemical sensor for the detection of alfuzosin (AFZ), a drug used to treat benign prostatic hyperplasia, using a double-shelled Co3O4/NiCo2O4 nanocomposite-modified electrode. The nanocomposites were synthesized using a template-assisted approach, with zeolitic imidazole framework-67 (ZIF-67) as the sacrificial template, involving the formation of uniform ZIF-67/Ni-Co layered double hydroxide (LDH) hollow structures followed by calcination to achieve the final nanocomposite. The nanocomposite was characterized by various techniques and showed high porosity, large surface area, and good conductivity. The nanocomposite-modified electrode exhibited excellent electrocatalytic activity towards AFZ oxidation, with a wide linear range of 5-180 µM and a low limit of detection of 1.37 µM. The sensor also demonstrated good repeatability, reproducibility, and stability selectivity in the presence of common interfering substances. The sensor was successfully applied to determine the AFZ in pharmaceutical tablets and human serum samples, with satisfactory recoveries. Our results suggest that the double-shelled Co3O4/NiCo2O4 nanocomposite is a promising material for the fabrication of electrochemical sensors for AFZ detection.

Vat photopolymerization 3D printing of Al2O3 ceramic cores with strip‐shaped pores by using polyamide 6 fiber template

AbstractThe complex ceramic core used for hollow turbine blades requires high porosity and flexural strength. This work combined vat photopolymerization 3D printing with sacrificial template method to prepare Al2O3 ceramic cores with strip‐shaped pores using polyamide 6 (PA6) fibers as templates. When the porosity was greater than 30%, the maximum flexural strength reached up to 110.48 MPa. The sacrificial templating method improved the porosity of Al2O3 ceramic cores, forming an internal porous structure that combined strip‐shaped large pores with irregularly shaped small pores. The influences of PA6 fiber content and diameter on the shrinkage, porosity, microstructure, and comprehensive properties of alumina ceramic cores were studied, revealing the mechanism of the coexistence of high porosity and high strength.

Corrosion Behavior of 30 ppi TAD3D/5A05Al Composite in Neutral Salt Spray Corrosion

This study created ceramic preforms with a 3D network structure (TAD3D) by using treated aluminum dross (TAD) and kaolin slurry, with 30 ppi polyurethane foam as a template via the sacrificial template method. TAD3D/5A05Al composites were then produced via pressureless infiltration of 5A05Al aluminum alloy into TAD3D. The corrosion behavior and resistance of TAD3D/5A05Al in salt spray were assessed via neutral salt spray corrosion (NSS), scanning electron microscopy (SEM), potentiodynamic polarization (PDP), and electrochemical impedance spectroscopy (EIS) tests. The results showed that after 24 to 360 h of NSS corrosion, the corrosion of the 5A05 matrix was primarily pitting, with pits expanding and deepening over time, and showing a tendency to interconnect. The main corrosion products were MgAl2O4, Al(OH)3, and Al2O3. As corrosion progressed, these products increased and filled cracks, pits, and grooves at the composite interface on the material’s surface. Corrosion products transferred to the grooves at the composite interface and grew on the ceramic surface. Corrosion products on the ceramic framework and the Al matrix can form a continuous passivation film covering the composite surface. PDP and EIS results indicated that the composite’s corrosion resistance decreased by 240 h but increased after that time. After 240 h, the surface passivation film can weaken corrosion effects and enhance the composite’s resistance, although it remained weaker than that of the uncorroded samples. Additionally, grooves at the composite interface deepened over time, with loosely structured corrosion products inside, potentially leading to severe localized corrosion.

Embedded metal inducing electron accumulation of multi-mesoporous pyridinic-N doped carbon for enhancing *COOH adsorption in electrochemical CO2 reduction

Nitrogen-doped carbon (NC) for carbon dioxide reduction reaction (CO2RR) are promising candidates. However, its selectivity and activity are limited by the undeveloped pore and limited electronic effect. Herein, we propose a strategy of three birds with one stone to utilize the embedded nickel for inducing electron-rich pyridinic-NC with multimodal porous structure based on the hard template assisted sacrificial template method. Nickel acts as sacrificial agent and inducer to facilitate the formation of mesoporous and reactive nitrogen species for capturing and activating reactants, respectively. Besides, we find that nickel as electron donor endows the NC with electron accumulation for participating actively in PCET reaction. The resultant Ni0.87-NC-1-AE exhibits an eminent FECO of 97.6 % with excellent activity and stability. In-situ Raman spectroscopy and the projected crystal orbital Hamilton populations (pCOHP) confirm the accumulation of *COOH and the stable adsorption of *COOH on the surface. What’s more, the well-designed experiments and DFT calculations accurately locate pyridinic-N as the active site, where the aggregated electrons donated by nickel significantly reduce the energy barrier of rate-determining step and promote the desorption of CO. This work provides an instructive perspective to construct advanced NC electrocatalysts with high mass transfer efficiency and high catalytic activity.

Monoliths for gas storage manufactured with precision pore engineering using 3D-printed templates

A fast, customizable, and systematic route for producing activated carbon monoliths for gas storage with low interparticle porosity (9 % to 24 %) containing tailored macro channels is disclosed. The production uses a three-dimensional (3D)-printed polymeric lattice, rich in oxygen, as a sacrificial template. Its interstitial voids are filled with a phenolic resin that is carbonized and activated at 1173 K under carbon dioxide (CO2). Sequential pyrolysis occurs via thermal treatment with the 3D-printed lattice removed first, rendering macro channels with the same shape as the template in accurately placed positions. Resulting in adsorbents with interparticle porosities ranging from 10 % to 23 %, calculated from X-ray micro-computed tomography (micro-CT) images. The axial resolution of these macro channels was similar to the SLA printing layer thickness used of 100 µm. Making it the best resolution attained to date in fabricating monoliths via a 3D-printed sacrificial templating method. Breakthrough experiments indicated healthy macro channel connectivity due to the reduced mass transfer zone. Moreover, excellent mechanical integrity was displayed, with a monolith withstanding 900 N before excessive fracturing occurred despite the presence of macro channels. Therefore, this method emphasizes its use for gas storage applications by enabling the adsorbent material to efficiently utilize the volumetric space while allowing a fast rate of adsorption over the entire structure.

Boost alkaline hydrogen evolution reaction by intermetallic charge transfer in perovskite ruthenate encapsulated in ZIF-67 derived cobalt sulfide nanoparticles

Constructing and manipulating heterostructure is an effective strategy to prepare electrocatalysts with excellent performance for water electrolysis. Herein, an efficient alkaline hydrogen evolution reaction (HER) electrocatalysts, Co3S4-embedded in carbon-encapsulated BaRuO3 (BaRuO3@CS-0.1), was synthesized through the sacrificial template method of ZIF-67 encapsulated BaRuO3 precursors. By inheriting the exceptional merits of different ingredients, this heterostructure catalyst BaRuO3@CS-0.1 enables intermetallic charge transfer between Ru and Co with boosted HER kinetics, and thus displaying higher catalytic activity towards HER, as evidenced by the intensively theoretical calculations and experimental measurements. BaRuO3@CS-0.1 exhibits excellent HER performance, with the lowered overpotentials of 26 mV to achieve 10 mA cm−2 in comparison to the pristine BaRuO3 (51 mV), which is also superior to Pt/C catalyst at large current density. Moreover, this heterostructure also demonstrates comparable oxygen evolution reaction (OER) activities with the representative electrocatalysts, delivering current densities of 10 mA cm−2 at a potential of 1.546 V for overall water splitting. These findings provide a rational route to optimize the performance of bulk electrocatalysts and endow them with richer electrochemical activity through this composite strategy.

"Microflower-Templated" Janus Sheets: Synthesis and Application in Stabilizing Foams.

In this study, we proposed a method for fabricating Janus sheets using biological "microflowers" as a sacrificial template. The microflower-templated Janus sheets (MF-JNSs) were employed as a foam stabilizer in foam separation of the whey soybean protein (WSP). The MF-JNSs took inorganic hybrid microflowers (BSA@Cu3 (PO4)2-MF) as template, followed by the sequential attachment of protamine and silica to the surface of the BSA@Cu3(PO4)2-MF. Subsequently, the template was removed using ethylenediaminetetraacetic acid after the silicon dioxide was modified by 3-(methacryloyloxy) propyl trimethoxysilane. Upon template dissolution, the modified silica layer, lacking support from the core, fractured to form the MF-JNSs. This method omitted the step of treating the hollow ball by external force and obtained Janus sheets in one step, indicating that it was simple and feasible. The morphology, structure, and composition of the MF-JNSs were analyzed by SEM, TEM, AFM, XRD, and FT-IR. The MF-JNSs were found to delay the breakage time of the Pickering emulsion, demonstrating their emulsion stabilizing capability. Importantly, they significantly enhanced the foam half-life and foam height of soybean whey wastewater (SWW). Moreover, the recovery percentage and enrichment ratio of WSP, separated from SWW by foam separation, were improved to 81 ± 0.28 and 1.20 ± 0.05%, respectively.

Synthesis of Na-Alginate templated Montmorillonite-Silica Composite as adsorbent for removal of Rhodamine B

In this study, mesoporous Montmorillonite-Silica composites prepared by using different amount Alginate as sacrificial template, for removal of Rhodamine B is investigated. By alternating Alginate amount it is aimed to switch the porosity of adsorbents thus the adsorption capacities of adsorbents. Synthesized adsorbents had been characterized by using Scanning Electron Microscopy, X-ray diffraction, Fourier transform infrared spectroscopy and N2-Ads/Des techniques. It is observed that beside the decrease in the micropore volume, the total pore volume of the adsorbents increased with the increasing of used Alginate amount. The total pore volumes of adsorbents synthesized with different Clay/Alginate ratio (10, 5, 1) were found as 0.116, 0.172, and 0.178 cm3/g, respectively. Batch adsorption studies showed that the maximum removal efficiencies were obtained at acidic conditions and the adsorbents had better fit with Freundlich isotherm. Qm values obtained from Langmuir isotherm were found as 24.47, 31.97 and 28.48 mg/g for synthesized adsorbents. Also, adsorption kinetic studies showed that for all adsorbents, experimental data had good fit to the pseudo-second order kinetics model. The model parameters were found as 5.9,6.3 and 6.5 (10–3 g/ (mg min). Thermodynamic parameters were also investigated in the study. Negative ∆Go values pointed out that the adsorption of RhB onto synthesized adsorbents was favorable process. Positive values of ∆Ho and ΔS indicated that the adsorption of RhB on adsorbents were endothermic and rising of randomness during the adsorption of RhB on the surface of the adsorbent. Adsorbents could be recovered at least five times without significant decrease in adsorption capacity.

Optimizing polymer composite dielectric properties via digital light processing 3D printing of ordered barium titanate skeleton

Through construction of a three-dimensional continuous ceramic network, the dielectric performance of polymer composites can be enhanced with a reduced amount of ceramic loading. However, the commonly employed methods, such as freeze casting or sacrificial template, fail to precisely control the structure of the ceramic skeleton, leading to significant randomness in content control. In this work, a Digital Light Processing (DLP) 3D printing technique is utilized to precisely fabricate ordered three-dimensional ceramic structures, which are further sintered at high temperatures to obtain a continuous barium titanate (BT) skeleton (BTS). This is then compounded with cyanate ester based polymers (CP) to prepare BTS/CP composites. Results show that when the content of BT is 61.2 vol%, the dielectric constant of the composite is 657 at 100 Hz, which is about 173 times higher than CP, while maintaining a lower dielectric loss of 0.026. Interestingly, the distribution of BTS in the composites has a significant impact on the dielectric performance of the composite. When the BT content is about 50 vol%, the dielectric constant of the “fine and dense” skeleton composite is 2.1 times higher than that of the “coarse and sparse” skeleton composite. This study proposes a novel strategy for building a structurally and compositionally controllable three-dimensional barium titanate (BT) network within polymers, demonstrating the noteworthy influence of macrostructure on the dielectric performance of polymer composites. This offers a fresh approach to the mass application of ordered three-dimensional ceramic skeleton enhanced polymer composites in the fields of electronics and electricity.

CeO2 nanocages with tetra-enzyme mimetic activities for dual-channel ratiometric colorimetric detection of microcystins-LR

BackgroundMicrocystin-leucine-arginine (MC-LR) produced by various cyanobacteria during harmful algal bloom poses serious threats to drinking water safety and human health. Conventional chromatography-based detection methods require expensive instruments and complicated sample pretreatment, limiting their application for on-site detection. Colorimetric aptasensors are simple and rapid, and are amenable to fast detection. However, they provide only one output signal, resulting in poor sensitivity and accuracy. Dual-channel ratiometric colorimetric method based on the peroxidase-like activity of nanozyme can achieve self-calibration by recording two reverse signals, providing significantly enhanced sensitivity and accuracy. ResultsCeO2 nanocages (CeO2 NCs) with tetra-enzyme mimetic activities (oxidase-, peroxidase-, catalase- and superoxide dismutase-like activities) were facilely synthesized using zeolitic imidazolate framework-67 (ZIF-67) as sacrificial template. The peroxidase-like activity of CeO2 NCs can be regulated by DNA, and it showed opposite response to two chromogenic substrates (2,2′-azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) and 3,3′,5,5′-tetramethylbenzidine (TMB)), which was mainly attributed to the changed affinity. On the basis of MC-LR aptamer-tunable peroxidase-like activity of CeO2 NCs in TMB and ABTS channel, a dual-channel ratiometric colorimetric aptasensor was constructed for detection of MC-LR. Compared with conventional single-signal colorimetric assays, the proposed method showed lower limit of detection (0.66 pg mL−1) and significantly enhanced sensitivity. Moreover, the practicability of the ratiometric colorimetric assay was demonstrated by detecting MC-LR in real water samples, and satisfactory recoveries (94.9–101.9 %) and low relative standard deviations (1.6–6.3 %) were obtained. SignificanceThis work presents a nanozyme-based ratiometric colorimetric aptasensor for MC-LR detection by recording the reverse responses of two chromogenic reactions. Benefiting from the self-calibration function, the method can achieve higher sensitivity and accuracy. The short detection time and practical application in real water samples show great potential for environmental monitoring.

Integration and characterization of a zeolite material in a microcomponent for measurements of environmental carbon dioxide

AbstractThis study demonstrates integration of a zeolite material in a ceramic microcomponent intended for use in sampling and analysis of environmental carbon dioxide (CO2). The zeolite material was integrated in bulk form, allowing for adsorption of large quantities of CO2 compared to previous integration attempts as thin films. To obtain a porous bulk material, an injectable slurry was developed, where expandable polymeric microspheres were added as a sacrificial template. By varying water and sphere contents of the slurry, it was possible to tune the porosity of the zeolite material between 55% and 72%. This in turn affected the flow resistance of the microcomponents, where an increase in the porosity of the filling from 62% to 72% reduced the flow resistance from 84 to 28 kPa min cm−3. In addition, the spheres facilitated complete fillings free from cracks. The zeolite material was seen to retain its ability to adsorb CO2 after processing, but it was not possible to quantify the level of retention compared to unprocessed zeolite.

Development of tunable porous alumina monolith using hollow microspheres via extrusion-based 3D printing

Hierarchical cellular ceramics have attracted considerable interest due to their versatility and unique physico-mechanical effectiveness for advanced applications. Tailorable alumina foams with low shrinkage were fabricated through an innovative combination of 3D printing and sacrificial templating with low environmental footprint. The viscoelastic pastes were formulated using the aqueous-based solution of binder, dispersant, and plasticizer with different volumes of α-alumina and lightweight hollow microspheres (HMs) as a template. The solid-to-liquid ratio increased 53–80 vol% with the inclusion of HMs for printable rheology. Cellular architectures of alumina were structured through a material extrusion-based technique and then thermally treated at 1200 °C. Finally, the alumina monoliths achieved a ∼55–93 % porosity with three different types of adjustable pores, produced by combining 3D printing, burning of templates, and inter-particle voids. The HMs generated spherical pores (7–47 µm) in the printing struts with reduced CO2 emissions compared to conventional sacrificial porogens during the burnout process.

3D hierarchical flowerball-like CoSe2/MnSe nanosheet arrays as a novel electrode for electrochemical sensing of hydrazine

Hydrazine (N2H4) is considered to be a highly toxic substance harmful to human body and environment, and has received much attention in the field of electrochemical detection in recent years. In this study, 3D hierarchical flowerball-like CoSe2/MnSe nanosheet arrays (CoSe2/MnSe FNSAs) were obtained using CoMn-LDH as precursor and cobalt glycerate spheres as the sacrificial template by simple hydrothermal reaction and selenization method. Bimetal selenides have more active electrochemical activity and more abundant electrochemical redox reactions. The unique hierarchical flowerball-like nanosheet array heterostructure can accelerate ionic diffusion kinetics and improve electron transfer. As a hydrazine electrochemical sensor, CoSe2/MnSe FNSAs exhibits excellent electrocatalytic performance with a wide detection range of 0.001–7.45 mM and a low detection limit of 0.4 μM. This strategy provides a new choice for the detection of environmental organic pollutants.

Design and optimization of CuCo-LDO catalysts via ZIF-67 sacrificial templates for enhanced toluene oxidation: A comprehensive study on morphology, structure, and catalytic activity

The investigation into the development of an active transition-metal oxide catalyst with controllable morphology for the degradation of volatile organic compounds (VOCs) is a subject of considerable importance and warrants further exploration. In this study, ZIF-67 was prepared and employed as a sacrificial template, with varying quantities of Cu ions incorporated to synthesize layered copper-cobalt double oxide (CuCo-LDO) featuring a modifiable surface state. A comprehensive characterization of the CuCo-LDO catalysts was conducted, encompassing structural properties, morphology, surface chemical state, and redox properties, utilizing a range of analytical techniques. Subsequent evaluations included testing the catalytic activity for toluene oxidation and assessing stability performance. The results revealed that differing Cu contents played a pivotal role in inducing changes in the morphology and structure of CuCo-LDO, thereby significantly influencing its oxidation activity towards toluene. Notably, the flower-like structure of 3CuCo-LDO (Cu% = 20.14 wt.%) exhibited outstanding toluene oxidation activity attributable to its unique structure and composition. This research contributes novel insights to the design of highs-performance catalysts targeting volatile organic compounds.

Template-assisted strategy for synthesizing transition metal oxyhydroxide for high-efficiency oxygen evolution reaction

Oxyhydroxides have been widely recognized as the true active species for oxygen evolution reaction (OER), while most of them are created via the complicated and time-consuming electrochemical activation process. Here, we develop a facile template-mediated method for directly synthesizing highly active oxyhydroxides toward OER. The optimal FeCoOOH prepared via using Cu2O as a sacrificial template could exhibit outstanding electrocatalytic OER performance, delivering a current density of 10 mA cm−2 with the overpotential of merely 320 mV, and a corresponding Tafel slope of 77.5 mV dec−1. Detailed mechanism study outlines that the extraordinary OER performance of such FeCoOOH originated from the intrinsically high OER activity of oxyhydroxide and the high specific surface area of the particular architecture. This work demonstrates a simple and direct route for the successful fabrication of highly active oxyhydroxides, which may open a new way for the synthesis of other active species.

Synthesis and catalytic properties of highly porous Ag-Rh nanocages

Ag-Rh nanocages are synthesised by a facile method at 190 °C using Ag nanocubes and Na3RhCl6 as sacrificial templates and precursor, respectively. Upon introduction of Na3RhCl6 into Ag nanocube suspension in ethylene glycol (EG) with poly(vinylpyrrolidone), Rh(III) ions are reduced by EG and Ag atoms via galvanic reaction; simultaneously, the released Ag(I) ions are reduced by EG. The reduction and co-deposition of both Ag and Rh atoms result in the formation of highly porous Ag-Rh nanocages when high volume of Na3RhCl6 is introduced. The Ag-Rh nanocages with Ag:Rh atomic ratio of 54.2:45.8 exhibit good catalytic activity toward the degradation of rhodamine 6G, reduction of 4-nitrophenol, and decomposition of hydrazine.

Multi-entropy electrocaloric film induced by three-dimensional thermal conductive ceramic network for synergistic thermal management

Imparting high thermal conductivity to electrocaloric refrigeration polymers is a promising solution for efficiently synergizing and accurately managing the vast heat generated by high-power density electronics. We employed a sacrificial template method to construct a three-dimensional thermally conductive SiOC ceramic network and embedded it in the electrocaloric polymer. The electrocaloric composite film with a 1 wt. % SiOC achieved a synergistic improvement in heat transfer and electrocaloric cooling, while the thermal diffusivity of the 10 wt. % composites increased sixfold. The three-dimensional ceramic network not only acted as a heat transfer pathway but also induced the transition of the electrocaloric polymer chain to a high-entropy state, increasing the number of dipole entities that could be driven by the electric field. The system reached a refrigeration temperature change of 2 K at a field strength of as low as 30 MV m−1. The high-entropy and high-crystallized electrocaloric composite film induced by the SiOC thermal conductive interface provides a tool for synergistic thermal management.

Negative Printing for the Reinforcement of In Situ Tissue-Engineered Cartilage.

In the realm of in situ cartilage engineering, the targeted delivery of both cells and hydrogel materials to the site of a defect serves to directly stimulate chondral repair. Although the in situ application of stem cell-laden soft hydrogels to tissue defects holds great promise for cartilage regeneration, a significant challenge lies in overcoming the inherent limitation of these soft hydrogels, which must attain mechanical properties akin to the native tissue to withstand physiological loading. We therefore developed a system where a gelatin methacryloyl hydrogel laden with human adipose-derived mesenchymal stem cells is combined with a secondary structure to provide bulk mechanical reinforcement. In this study, we used the negative embodied sacrificial template 3D printing technique to generate eight different lattice-based reinforcement structures made of polycaprolactone, which ranged in porosity from 80% to 90% with stiffnesses from 28 ± 5 kPa to 2853 ± 236 kPa. The most promising of these designs, the hex prism edge, was combined with the cellular hydrogel and retained a stable stiffness over 41 days of chondrogenic differentiation. There was no significant difference between the hydrogel-only and hydrogel scaffold group in the sulfated glycosaminoglycan production (340.46 ± 13.32 µg and 338.92 ± 47.33 µg, respectively) or Type II Collagen gene expression. As such, the use of negative printing represents a promising solution for the integration of bulk reinforcement without losing the ability to produce new chondrogenic matrix.

Creation of Porous, Perfusable Microtubular Networks for Improved Cell Viability in Volumetric Hydrogels.

The creation of large, volumetric tissue-engineered constructs has long been hindered due to the lack of effective vascularization strategies. Recently, 3D printing has emerged as a viable approach to creating vascular structures; however, its application is limited. Here, we present a simple and controllable technique to produce porous, free-standing, perfusable tubular networks from sacrificial templates of polyelectrolyte complex and coatings of salt-containing citrate-based elastomer poly(1,8-octanediol-co-citrate) (POC). As demonstrated, fully perfusable and interconnected POC tubular networks with channel diameters ranging from 100 to 400 μm were created. Incorporating NaCl particulates into the POC coating enabled the formation of micropores (∼19 μm in diameter) in the tubular wall upon particulate leaching to increase the cross-wall fluid transport. Casting and cross-linking gelatin methacrylate (GelMA) suspended with human osteoblasts over the free-standing porous POC tubular networks led to the fabrication of 3D cell-encapsulated constructs. Compared to the constructs without POC tubular networks, those with either solid or porous wall tubular networks exhibited a significant increase in cell viability and proliferation along with healthy cell morphology, particularly those with porous networks. Taken together, the sacrificial template-assisted approach is effective to fabricate tubular networks with controllable channel diameter and patency, which can be easily incorporated into cell-encapsulated hydrogels or used as tissue-engineering scaffolds to improve cell viability.