| 1. |
- Abdelhamid, Hani Nasser, 1986-, et al.
(författare)
-
3D printing of cellulose/leaf-like zeolitic imidazolate frameworks (CelloZIF-L) for adsorption of carbon dioxide (CO2) and heavy metal ions
- 2023
-
Ingår i: Dalton Transactions. - : Royal Society of Chemistry (RSC). - 1477-9226 .- 1477-9234. ; 52:10, s. 2988-2998
-
Tidskriftsartikel (refereegranskat)abstract
- Metal–organic frameworks (MOFs) have advanced several technologies. However, it is difficult to market MOFs without processing them into a commercialized structure, causing an unnecessary delay in the material's use. Herein, three-dimensional (3D) printing of cellulose/leaf-like zeolitic imidazolate frameworks (ZIF-L), denoted as CelloZIF-L, is reported via direct ink writing (DIW, robocasting). Formulating CelloZIF-L into 3D objects can dramatically affect the material's properties and, consequently, its adsorption efficiency. The 3D printing process of CelloZIF-L is simple and can be applied via direct printing into a solution of calcium chloride. The synthesis procedure enables the formation of CelloZIF-L with a ZIF content of 84%. 3D printing enables the integration of macroscopic assembly with microscopic properties, i.e., the formation of the hierarchical structure of CelloZIF-L with different shapes, such as cubes and filaments, with 84% loading of ZIF-L. The materials adsorb carbon dioxide (CO2) and heavy metals. 3D CelloZIF-L exhibited a CO2 adsorption capacity of 0.64–1.15 mmol g−1 at 1 bar (0 °C). The materials showed Cu2+ adsorption capacities of 389.8 ± 14–554.8 ± 15 mg g−1. They displayed selectivities of 86.8%, 6.7%, 2.4%, 0.93%, 0.61%, and 0.19% toward Fe3+, Al3+, Co2+, Cu2+, Na+, and Ca2+, respectively. The simple 3D printing procedure and the high adsorption efficiencies reveal the promising potential of our materials for industrial applications.
|
|
| 2. |
- Abdelhamid, Hani Nasser, 1986-, et al.
(författare)
-
Binder-free Three-dimensional (3D) printing of Cellulose-ZIF8 (CelloZIF-8) for water treatment and carbon dioxide (CO2) adsorption
- 2023
-
Ingår i: Chemical Engineering Journal. - 1385-8947 .- 1873-3212. ; 468
-
Tidskriftsartikel (refereegranskat)abstract
- Metal-organic frameworks (MOFs) have advanced several applications, including energy, biomedical and envi-ronmental remediation. However, most of the reported MOF materials are in powder form limiting their ap-plications. This study reported the processing of MOF via three-dimensional (3D) printing of cellulose-MOFs (denoted as CelloMOFs). The 3D printing procedure involved a one-pot method including three steps: gel for-mation, 3D printing, and in-situ growth of MOF crystals. This procedure offered 3D printing of CelloMOF via a binder-free method with high loading of 67.5 wt%. The 3D-printed porous structures were used as adsorbents for carbon dioxide (CO2), dye, and heavy metal ions. They can be also used as catalysts for the degradation of water pollutants such as organic dyes. The materials can be separated easily without requiring extra procedures such as centrifugation or filtration. The materials offered complete (>99%) removal of organic dyes within 10 min with high selectivity toward anionic dyes e.g, methyl blue (MeB). The materials exhibited CO2 and heavy metal ions adsorption capacities of 0.63 mmol/g (27.7 mg/g) and 8-328 mg/g, respectively, with good recyclability. Our methodology will open new venues for advanced 3D printing of CelloMOF and its applications for water treatment and air purification.
|
|
| 3. |
- Abdelhamid, Hani Nasser, 1986-, et al.
(författare)
-
Three-Dimensional Printing of Cellulose/Covalent Organic Frameworks (CelloCOFs) for CO2 Adsorption and Water Treatment
- 2023
-
Ingår i: ACS Applied Materials and Interfaces. - 1944-8244 .- 1944-8252. ; 15:51, s. 59795-59805
-
Tidskriftsartikel (refereegranskat)abstract
- The development of porous organic polymers, specifically covalent organic frameworks (COFs), has facilitated the advancement of numerous applications. Nevertheless, the limited availability of COFs solely in powder form imposes constraints on their potential applications. Furthermore, it is worth noting that COFs tend to undergo aggregation, leading to a decrease in the number of active sites available within the material. This work presents a comprehensive methodology for the transformation of a COF into three-dimensional (3D) scaffolds using the technique of 3D printing. As part of the 3D printing process, a composite material called CelloCOF was created by combining cellulose nanofibrils (CNF), sodium alginate, and COF materials (i.e., COF-1 and COF-2). The intervention successfully mitigated the agglomeration of the COF nanoparticles, resulting in the creation of abundant active sites that can be effectively utilized for adsorption purposes. The method of 3D printing can be described as a simple and basic procedure that can be adapted to accommodate hierarchical porous materials with distinct micro- and macropore regimes. This technology demonstrates versatility in its use across a range of COF materials. The adsorption capacities of 3D CelloCOF materials were evaluated for three different adsorbates: carbon dioxide (CO2), heavy metal ions, and perfluorooctanesulfonic acid (PFOS). The results showed that the materials exhibited adsorption capabilities of 19.9, 7.4–34, and 118.5–410.8 mg/g for CO2, PFOS, and heavy metals, respectively. The adsorption properties of the material were found to be outstanding, exhibiting a high degree of recyclability and exceptional selectivity. Based on our research findings, it is conceivable that the utilization of custom-designed composites based on COFs could present new opportunities in the realm of water and air purification.
|
|
| 4. |
|
|
| 5. |
|
|
| 6. |
|
|
| 7. |
|
|
| 8. |
- Sultan, Sahar, 1987-, et al.
(författare)
-
3D printed porous bioscaffolds based on cellulose nanocrystals
- 2019
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Nanocellulose extracted from natural resources are used extensively in biomedical field. They have properties of cellulose, such as potential for chemical modification, low toxicity, biocompatibility, biodegradability, low toxicity, high mechanical properties, renewability as well as nanoscale characteristics like high specific surface area, rheological and optical properties. Due to the inherent shear thinning property of nanocellulose, the 3-Dimensional (3D) printing technique has revolutionized the bioscaffolds with customization, complex geometries, controlled porosity, bioprinting and hierarchical features, in terms of composition and structural designs. Furthermore, during 3D printing the high aspect ratio of cellulose nanocrystals (CNCs) is expected to induce shear alignment yielding directionality in the 3D printed scaffolds. CNCs based double crosslinked interpenetrating polymer network (IPN) hydrogel has been made and 3D printed into 2D and 3D scaffolds with uniform and gradient porosity. The pore sizes are in the range of 80-2080 µm and 195-2382 µm in the wet and freeze-dried states respectively. These pores are distributed in a controlled manner that in turn provides gradation in density and porosity of the 3D printed hydrogel scaffolds. The directionality studies showed that CNCs tend to align parallel to the printing direction and degree of orientation varies between 61-76 %, depending on the point of measurement within the 3D printed scaffolds. In addition, this study also highlights the importance of nozzle movement during 3D printing to achieve scaffolds with better resolution, higher dimensions and good shape fidelity. The alignment of nanocrystals in this work yields directionality that can serve as an important step toward the development of tailored architectures. This study demonstrates the potential of 3D printing in developing bio-based scaffolds with controlled pore sizes, gradient pore structures and customized geometry for optimal tissue regeneration applications.
|
|
| 9. |
- Sultan, Sahar, 1987-, et al.
(författare)
-
3D Printed Porous Cellulose Nanocomposite Hydrogel Scaffolds
- 2019
-
Ingår i: Journal of Visualized Experiments. - : MyJove Corporation. - 1940-087X. ; :146
-
Tidskriftsartikel (refereegranskat)abstract
- This work demonstrates the use of three-dimensional (3D) printing to produce porous cubic scaffolds using cellulose nanocomposite hydrogel ink, with controlled pore structure and mechanical properties. Cellulose nanocrystals (CNCs, 69.62 wt%) based hydrogel ink with matrix (sodium alginate and gelatin) was developed and 3D printed into scaffolds with uniform and gradient pore structure (110-1,100 µm). The scaffolds showed compression modulus in the range of 0.20-0.45 MPa when tested in simulated in vivo conditions (in distilled water at 37 °C). The pore sizes and the compression modulus of the 3D scaffolds matched with the requirements needed for cartilage regeneration applications. This work demonstrates that the consistency of the ink can be controlled by the concentration of the precursors and porosity can be controlled by the 3D printing process and both of these factors in return defines the mechanical properties of the 3D printed porous hydrogel scaffold. This process method can therefore be used to fabricate structurally and compositionally customized scaffolds according to the specific needs of patients.
|
|
| 10. |
- Sultan, Sahar, 1987-, et al.
(författare)
-
3D printing of nano-cellulosic biomaterials for medical applications
- 2017
-
Ingår i: Current Opinion in Biomedical Engineering. - : Elsevier BV. - 2468-4511. ; 2, s. 29-34
-
Forskningsöversikt (refereegranskat)abstract
- Nanoscaled versions of cellulose viz. cellulose nanofibers (CNF) or cellulose nanocrystals (CNC) isolated from natural resources are being used extensively since the past decade in the biomedical field e.g. for tissue engineering, implants, drug delivery systems, cardiovascular devices, and wound healing due to their remarkable mechanical, chemical and biocompatible properties. In the recent years, 3D printing of nanocellulose in combination with polymers is being studied as a viable route to future regenerative therapy. The printability of nanocellulose hydrogels owing to their shear thinning behavior and the possibility to support living cells allows 3D bioprinting using nanocellulose, a recent development which holds tremendous potential.
|
|
| 11. |
- Sultan, Sahar, 1987-
(författare)
-
Cello-Apatite: 3D printed biphasic scaffolds based on in-situhydroxyapatite-nanocellulose hydrogels for osteochondral defects
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The osteochondral tissue is a complex structure composedof articular cartilage, calcified cartilageand subchondral bone, which havedifferent intrinsic structures and physiologicalfunctions butintegrate well with each other for weight bearing andfunctional joint movement. Anosteochondraldefectinvolvesboth the cartilage and the underlying bone;therefore,a bilayer scaffold isneeded to satisfy the individual requirements of osteochondralregeneration.The scaffold geometry also plays a crucial role in its success by influencing the cell distribution, integration with the host tissue and capillary ingrowth.TOCNF and mineralized TOCNF hydrogels(TOCNF-HAP)were3D printedinto porous scaffoldsfor the regeneration of cartilage and bone tissues, respectively. Amineral content of 67wt% was chosen to mimic the quantity in the human bone and was validatedby the presence of characteristic hydroxyapatite peaks in XRD,visualized using SEM and TEMand quantified using TGA.The mechanical properties of the 3D printed mineralized TOCNF scaffoldsshowed significant increasecompared to their non-mineralized TOCNF scaffold. Moreover, TOCNF and TOCNF-HAP Comments restricted to single page 2wereused to 3D print a biphasic hydrogel scaffold to be used for repair and regeneration of cartilage and bone simultaneously. Theprepared scaffoldmimicked thecomposition, structure and modulusof natural tissues and offer amicroenvironment for sustainingcell attachment and viabilityin terms of osteochondral regeneration.
|
|
| 12. |
- Sultan, Sahar, 1987-
(författare)
-
Nanocellulose based 3D printed hydrogel scaffolds for cartilage and bone regeneration : Tuning of composition, pore structure and functions
- 2022
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Biobased-materials with customized scaffolds have played a prominent role in the success of tissue engineering (TE). Cellulose nanomaterials (CNM) isolated from the abundant biopolymer, cellulose, is explored in this thesis for TE engineering due to its versatile properties such as biocompatibility, high specific strength, surface functionality and water retention capacity. Hydrogel formation capability of CNM at low concentrations (1–2 wt%) and shear thinning behavior has facilitated its use in 3-dimensional (3D) printing as a fabrication technique for 2-dimensional (2D) and 3D scaffolds. This technique offers 3D scaffolds with tailored, controlled and complex geometries having precise micro and macro scaled structures. The current work focuses on CNM-based 3D printed hydrogel scaffolds with tuned composition and pore structure for cartilage and bone regeneration. Design of CNM hydrogel formulations with suitable rheological properties, hydrogel inks capable of ex-situ crosslinking, print resolution during printing due to swelling and mechanical and dimensional stability of the printed scaffolds in moist environment are key challenges that were addressed.Inspired by the hierarchical and gradient nature of natural tissues 3D printed hydrogel scaffolds with gradient pore structure and composition are reported for the first time with focus on cellulose nanocrystals (CNC) and TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl radical)-oxidized cellulose nanofibers (TOCNF) based hydrogel ink printing for advanced and functional scaffolds.CNC-based hydrogel ink was used to 3D print uniform and gradient porous cubic scaffolds for cartilage regeneration. This work highlighted the importance of nozzle movement to obtain high resolution scaffolds with higher z-axis. The anisotropic rigid CNC aligned themselves along the printing direction due to the shear induced orientation that was quantified between 61–76%. To obtain adequate mechanical properties (0.20–0.45 MPa) suitable for cartilage regeneration, the hydrogel ink solid content was increased almost two-fold (5.4 wt% to 9.9 wt%) while exhibiting and mimicking the viscoelasticity of natural cartilage tissues. To improve the bioactivity of the CNC-based 3D printed scaffolds, a surface treatment through dopamine coating was performed. This coating enhanced the hydrophilicity and capability of 3D printed scaffolds to bind bioactive molecules such as fibroblast growth factor (FGF-18) for soft TE scaffolds.Surface functionality of TOCNF was utilized to fabricate functional hybrid scaffolds (CelloZIF-8) through one-pot in- situ synthesis of Metal-Organic frameworks (MOFs) with varied ZIF-8 loadings (30.8–70.7%). The inherent porosity of the ZIF-8 was used for loading and stimuli-responsive (pH-dependent) releasing of drug molecule such as curcumin. The developed CelloMOF system was extended to other MOFs (MIL-100) and drugs (methylene blue). The shear thinning property of TOCNF was reserved after MOFs hybridization and was used to 3D print porous scaffolds with excellent shape fidelity. In Cello-Apatite, TOCNF was also used as template for in-situ synthesis of hydroxyapatite (HAP) where the HAP loading was 67 wt% to mimic the bone composition. In an attempt to address both cartilage and bone regeneration, a biphasic osteochondral 3D printed hydrogel scaffold has been introduced with tuned composition, pore structure and mechanical properties.The work presents a sustainable, cost effective and scalable approach for TE using biobased and toxic free water-based formulations using low temperature processes that are extendable to other biomaterials as well as to other applications, such as water treatment.
|
|
| 13. |
- Sultan, Sahar, 1987-, et al.
(författare)
-
The Design of 3D-Printed Polylactic Acid–Bioglass Composite Scaffold : A Potential Implant Material for Bone Tissue Engineering
- 2022
-
Ingår i: Molecules. - : MDPI AG. - 1431-5157 .- 1420-3049. ; 27:21
-
Tidskriftsartikel (refereegranskat)abstract
- Bio-based and patient-specific three-dimensional (3D) scaffolds can present next generation strategies for bone tissue engineering (BTE) to treat critical bone size defects. In the present study, a composite filament of poly lactic acid (PLA) and 45S5 bioglass (BG) were used to 3D print scaffolds intended for bone tissue regeneration. The thermally induced phase separation (TIPS) technique was used to produce composite spheres that were extruded into a continuous filament to 3D print a variety of composite scaffolds. These scaffolds were analyzed for their macro- and microstructures, mechanical properties, in vitro cytotoxicity and in vivo biocompatibility. The results show that the BG particles were homogeneously distributed within the PLA matrix and contributed to an 80% increase in the mechanical strength of the scaffolds. The in vitro cytotoxicity analysis of PLA-BG scaffolds using L929 mouse fibroblast cells confirmed their biocompatibility. During the in vivo studies, the population of the cells showed an elevated level of macrophages and active fibroblasts that are involved in collagen extracellular matrix synthesis. This study demonstrates successful processing of PLA-BG 3D-printed composite scaffolds and their potential as an implant material with a tunable pore structure and mechanical properties for regenerative bone tissue engineering.
|
|
| 14. |
- Sultan, Sahar, 1987-, et al.
(författare)
-
Three-Dimensional Printing of Nanocellulose-Based Hydrogels
- 2021
-
Ingår i: Nano Hydrogels. - Singapore : Springer Nature. - 9789811571374 - 9789811571381 ; , s. 1-20
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- This chapter gives an overview of the recent developments in the field of three-dimensional (3D) printing of nanocellulose-based hydrogels. Nanocellulose has gained much attention due to its renewable sources, low toxicity, biocompatibility, good mechanical properties and availability of surface charges for further modifications as well as in situ growth of functional nanoparticles. Moreover, suitable rheological properties of nanocellulose are helpful in utilizing 3D printing technique for producing constructs with customized, controlled and complex geometries. This technique offers a high-resolution 3D constructs with precise micro- and macroscaled structures and can be extended to 3D bioprinting, where living cells are mixed in hydrogel inks. As the name suggests, nanocellulose-based hydrogel inks contain nanocellulose as reinforcement phase, while other crosslinkable biopolymers can serves as matrix phase.
|
|
