原花青素和三聚磷酸钠交联提升可食性细胞培养肉支架性能

    Support perfoemance enhancement of edible cell culture meat scaffolds crosslinked by procyanidins and sodium tripolyphosphate

    • 摘要: 交联对于提升胶原蛋白基可食性细胞培养肉(cell cultured meat,CCM)支架性能至关重要。为探究交联剂原花青素(proanthocyanidins,PA)及三聚磷酸钠(sodium tripolyphosphate,TPP)及不同交联方式对可食性CCM支架性能精准可控的提升作用,制备了牛骨胶原蛋白(bovine bone collagen,BBC)/壳聚糖(chitosan,CS)自交联原纤维凝胶,通过PA、TPP及PA+TPP进一步交联获得BBC/CS支架样品(B/C/P、B/C/T、B/C/PT);并分别进行了样品交联前后的分子结构、理化特性和生物相容性的对比研究。结果表明:交联改善支架的结构且不影响BBC三螺旋分子结构的完整性,而B/C/P交联程度和结构有序性更高。交联后的B/C/P (98.3%,136 μm)、B/C/PT(96.5%,175 μm)和B/C/T(94.8%,203 μm)显示更高的孔隙率,但孔径更小。交联改善了BBC/CS支架的热稳定性,但并未发现支架在更大温度范围内的热稳定性明显增强。同时,交联后的BBC/CS支架样品表现出性能提升,包括更低的溶散度,更高的交联度、溶胀率/保水率、酶抗性、机械强度及生物相容性。PA和TPP的潜在交联作用机制可能分别主要依靠其大量的羟基与BBC产生的氢键交联作用和其磷酸根与CS的氨基产生的离子交联作用,因而三种不同的交联方式(PA、TPP、PA+TPP)可基于不同作用机制,以不同成本、不同程度的精准提升BBC/CS支架性能。因此,在不同类型的可食性CCM支架生产实践中可基于支架的具体性能要求、生产成本及交联效率等因素,综合考虑采用适当的交联方式实现精准控制。研究结果可为基于PA和TPP交联构建性质和成本优良可控的可食性CCM支架提供参考。

       

      Abstract: Crosslinking is crucial to enhance the physicochemical properties of collagen-based edible scaffolds for cell-cultured meat (CCM). This study aims to systematically investigate the precise and controllable enhancement of cross-linking agents proanthocyanidins (PA), sodium tripolyphosphate (TPP) and different cross-linking means (PA/TPP/PA+TPP) on the performance of edible CCM scaffolds. Bovine bone collagen (BBC)/chitosan (CS) self-crosslinked fibrillar gels (B/C) were first prepared at the optimal stoichiometric ratio of 4:1 (w/w). Afterward, BBC/CS scaffolds, including PA-crosslinked BBC/CS scaffolds (B/C/P), TPP-crosslinked BBC/CS scaffolds (B/C/T), and PA+TPP-crosslinked BBC/CS scaffolds (B/C/PT) were prepared by immersing B/C in PA for 2 h, TPP for 2 h, and a combination of PA for 1 h followed by TPP for 1 h, respectively. Subsequently, a comparative assessment was conducted on the molecular structure (hydrogen bonding, degree of molecular order, triple-helical structure integrity, and degree of crystallinity), physicochemical properties (porosity, thermal stability, crosslinking degree, swelling/water retention ratio, dissolution degree, enzymatic resistance capacity, and mechanical strength), and biocompatibility (seeding efficiency and cell viability) of the samples before (B/C) and after crosslinking (B/C/P, B/C/T, and B/C/PT). Results from Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Diffraction (XRD) showed that the crosslinking improved the molecular structure of the BBC/CS scaffolds without affecting the triple-helical structure integrity of BBC. The BBC/CS scaffolds exhibited a higher degree of molecular order and crystallinity, as well as more and tighter hydrogen bonding interactions, compared with B/C. Scanning electron microscopy (SEM) revealed that the B/C/P (98.3%/136 μm), B/C/PT (96.5%/175 μm), and B/C/T (94.8%/203 μm) shared higher porosity but smaller pore sizes, compared with the BBC/CS fibrillar gels (93.2%/265 μm). Differential scanning calorimetry (DSC) results showed that the crosslinking improved the thermal stability of the BBC/CS scaffolds within a smaller temperature range (10~100 ℃) rather than a larger temperature range (30~500 ℃), compared with B/C. The thermal stability of crosslinked scaffolds was ranked as follows: B/C/P (Tm 66.8 ℃, ΔH 13.52 J/g), B/C/PT (Tm 60.6 ℃, ΔH 10.26 J/g), and B/C/T (Tm 62.2℃, ΔH 8.71 J/g), compared with the B/C (Tm 55.6 ℃, ΔH 5.26 J/g) and BBC (Tm 51.3 ℃, ΔH 3.11 J/g). The cross-linked BBC/CS scaffolds exhibited a lower dissolution ratio (B/C/P: 17.3%, B/C/PT: 31.6%, and B/C/T: 35.9%), while a higher degree of crosslinking (B/C/P: 46.53%, B/C/PT: 38.96%, B/C/T: 30.61%), swelling/water retention ratio (B/C/P: 68/7.0 times, B/C/PT: 45/5.3 times, B/C/T: 37/4.4 times, weight after moisture absorption equilibrium to initial dry weight), enzymatic resistance capacity (B/C/P: 11.1%, B/C/PT: 20.6%, B/C/T: 23.2%), mechanical strength (B/C/P: 12.5 kPa, B/C/PT: 10.2 kPa, B/C/T: 11.9 kPa), and biocompatibility (B/C/P: 86.37%/ 118.33%, B/C/PT: 79.33%/ 115.68%, B/C/T: 63.52%/ 112.82%, seeding efficiency and cell viability, respectively), compared with the B/C (dissolution ratio 55.6%; swelling/water retention ratio 25/2.9 times; enzyme resistance capacity 35.2%; mechanical strength 5.6 kPa; seeding efficiency 56.59%/cell viability 100%). Generally, BBC/CS scaffolds shared superior physicochemical properties, compared with B/C. The B/C/P showed better performance than B/C/T and B/C/PT. The potential crosslinking mechanisms of PA and TPP predominantly relied on the extensive hydrogen bonding between the abundant hydroxyl groups of PA and BBC, as well as the ionic interactions between the phosphate ions of TPP and the amino groups of CS. The three different crosslinking means (PA, TPP, PA+TPP) can accurately improve the performance of BBC/CS scaffolds with different costs and degrees based on their different mechanisms. Therefore, in the production of different edible CCM scaffolds, appropriate crosslinking methods can be comprehensively considered based on the specific performance requirements, production costs, and crosslinking efficiency to achieve precise control. The study provide reference for the construction of edible CCM scaffolds with excellent properties and controllable cost based on PA and TPP cross-linking.

       

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