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Lou L, Rubinsky B. Temperature-Controlled 3D Cryoprinting Inks Made of Mixtures of Alginate and Agar. Gels 2023; 9:689. [PMID: 37754370 PMCID: PMC10530365 DOI: 10.3390/gels9090689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 08/20/2023] [Accepted: 08/24/2023] [Indexed: 09/28/2023] Open
Abstract
Temperature-controlled 3D cryoprinting (TCC) is an emerging tissue engineering technology aimed at overcoming limitations of conventional 3D printing for large organs: (a) size constraints due to low print rigidity and (b) the preservation of living cells during printing and subsequent tissue storage. TCC addresses these challenges by freezing each printed voxel with controlled cooling rates during deposition. This generates a rigid structure upon printing and ensures cell cryopreservation as an integral part of the process. Previous studies used alginate-based ink, which has limitations: (a) low diffusivity of the CaCl2 crosslinker during TCC's crosslinking process and (b) typical loss of print fidelity with alginate ink. This study explores the use of an ink made of agar and alginate to overcome TCC protocol limitations. When an agar/alginate voxel is deposited, agar first gels at above-freezing temperatures, capturing the desired structure without compromising fidelity, while alginate remains uncrosslinked. During subsequent freezing, both frozen agar and alginate maintain the structure. However, agar gel loses its gel form and water-retaining ability. In TCC, alginate crosslinking occurs by immersing the frozen structure in a warm crosslinking bath. This enables CaCl2 diffusion into the crosslinked alginate congruent with the melting process. Melted agar domains, with reduced water-binding ability, enhance crosslinker diffusivity, reducing TCC procedure duration. Additionally, agar overcomes the typical fidelity loss associated with alginate ink printing.
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Affiliation(s)
- Leo Lou
- Department of Bioengineering, University of California Berkeley, Berkeley, CA 94720, USA;
| | - Boris Rubinsky
- Department of Bioengineering, University of California Berkeley, Berkeley, CA 94720, USA;
- Department of Mechanical Engineering, University of California Berkeley, Berkeley, CA 94720, USA
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Li C, Li X, Gu Q, Xie L, Cai Y, Liao L. Synthesis, characterization and potential applications for oxidized agarose. Int J Biol Macromol 2023; 242:124643. [PMID: 37119904 DOI: 10.1016/j.ijbiomac.2023.124643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Revised: 04/14/2023] [Accepted: 04/24/2023] [Indexed: 05/01/2023]
Abstract
The knowledge of agarose (AG) oxidation using periodate as oxidizer has not been systematically explored. This paper synthesized oxidized agarose (OAG) using solid-sate and solution reaction methods; the reaction mechanism and the properties of OAG samples were systematically evaluated. Chemical structure analysis disclosed that the aldehyde group and carboxyl group contents in all OAG samples are extremely low. Meanwhile, crystallinity, dynamic viscosity and molecular weight of OAG samples is lower than that of the original AG. Reaction temperature, time and sodium periodate dosage are inversely proportional to the decline of the gelling temperature (Tg) and melting temperature (Tm); and the Tg and Tm for the OAG sample obtained are even 19 °C and 22 °C lower than that of the original AG. The as-synthesized OAG samples all possess excellent cytocompatibility and blood compatibility; and can promote the proliferation and migration of fibroblast cells. Last but not least, the gel strength, hardness, cohesiveness, springiness and chewiness of the OAG gel can be effectively regulated via oxidation reaction. In conclusions, both solid and solution oxidation can regulate the physical properties of OAG and enlarge its potential applications in wound dressing, tissue engineering and food areas.
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Affiliation(s)
- Chengpeng Li
- School of Chemistry and Environmental Science, Guangdong Ocean University, Zhanjiang 524088, China.
| | - Xianzhu Li
- School of Chemistry and Environmental Science, Guangdong Ocean University, Zhanjiang 524088, China; Agricultural Product Processing Research Institute, Chinese Academy of Tropical Agricultural Sciences, Zhanjiang 524001, China
| | - Qixiang Gu
- School of Chemistry and Environmental Science, Guangdong Ocean University, Zhanjiang 524088, China; Agricultural Product Processing Research Institute, Chinese Academy of Tropical Agricultural Sciences, Zhanjiang 524001, China
| | - Lici Xie
- School of Chemistry and Environmental Science, Guangdong Ocean University, Zhanjiang 524088, China
| | - Ying Cai
- School of Chemistry and Environmental Science, Guangdong Ocean University, Zhanjiang 524088, China
| | - Lusheng Liao
- Agricultural Product Processing Research Institute, Chinese Academy of Tropical Agricultural Sciences, Zhanjiang 524001, China; Guangdong Provincial Key Laboratory of Natural Rubber Processing, Agricultural Products Processing Research Institute of Chinese Academy of Tropical Agricultural Sciences, Zhanjiang 524001, China.
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Asad N, Smith E, Shakya S, Stegman S, Timmons L. Sustainable Methodologies for Efficient Gel Electrophoresis and Streamlined Screening of Difficult Plasmids. Methods Protoc 2023; 6:mps6020025. [PMID: 36961045 PMCID: PMC10037626 DOI: 10.3390/mps6020025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 02/17/2023] [Accepted: 02/22/2023] [Indexed: 03/08/2023] Open
Abstract
We describe a workflow for efficient, environmentally attentive, and sustainable practices related to routine agarose gel electrophoresis. The methods reduce plastic waste and improve efficiency, especially for the exhaustive screening of difficult-to-obtain plasmids. Sustainability is increased when agarose is used ten times over by virtue of a thorough recycling regimen. The workflow optimizes workspaces and standardizes lab practices for handling potentially hazardous waste, minimizing environmental harm. Safety, efficiency, and sustainability improve laboratory productivity, help minimize environmental contamination, and increase cost-effectiveness.
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Affiliation(s)
- Nadeem Asad
- Department of Molecular Biosciences, The University of Kansas, 1200 Sunnyside Avenue, Lawrence, KS 66045, USA
- Department of Biochemistry and Molecular Medicine, 64 Medical Center Drive, University of West Virginia Health Science Center, Morgantown, WV 26506, USA
| | - Emily Smith
- Department of Molecular Biosciences, The University of Kansas, 1200 Sunnyside Avenue, Lawrence, KS 66045, USA
- Department of Neurobiology, Physiology & Behavior, University of California, Davis, CA 95618, USA
- Department of Psychiatry and Behavioral Sciences, University of California, Davis, CA 95618, USA
- Center for Neuroscience, University of California, Davis, CA 95618, USA
| | - Sudeep Shakya
- Department of Molecular Biosciences, The University of Kansas, 1200 Sunnyside Avenue, Lawrence, KS 66045, USA
| | - Sutton Stegman
- Department of Molecular Biosciences, The University of Kansas, 1200 Sunnyside Avenue, Lawrence, KS 66045, USA
| | - Lisa Timmons
- Department of Molecular Biosciences, The University of Kansas, 1200 Sunnyside Avenue, Lawrence, KS 66045, USA
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