Department of Chemistry, CICECO, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal.
Soft Matter. 2018 Jul 11;14(27):5622-5627. doi: 10.1039/c8sm00921j.
The need to better mimic native tissues has accompanied research in tissue engineering and controlled drug delivery. The development of new platforms for cell and drug encapsulation followed the same trend, and studying the influence of the delivery material system's geometry has been gaining momentum. Aiming to investigate how an increase in surface area and varying particle shape could impact drug release and cell viability, a novel method was developed to produce spheroidal hydrogel particles with adjustable circularity, aiming to tune drug delivery. For this purpose, droplets of hydrogel precursor were squeezed between two superamphiphobic surfaces separated with spacers with different height, and then photo-crosslinked to maintain the acquired shape after "de-sandwiching". Numerical modelling studies were performed to study the polymeric droplet geometry deformation process, which were consistent with experimentally obtained results. The spheroidal particles were produced under mild conditions using methacrylated chitosan, capable of encapsulating proteins or cells. Likely due to their higher surface area to volume-ratio, compared to spherical-shaped ones, spheroids presented an improved viability of encapsulated cells due to enhanced nutrient diffusion to the core, and led to a significantly faster drug release rate from the polymer network. These results were also assessed numerically, in which the drug release rate was computed for different spheroidal-like geometries. Hence, the described method can be used to manufacture spheroidal particles with tailored geometry that can be broadly applied in the biomedical field, including for drug delivery or as cell encapsulation platforms.
为了更好地模拟天然组织，组织工程和控制药物输送的研究都需要如此。用于细胞和药物包封的新平台的开发也遵循了同样的趋势，并且研究输送材料系统的几何形状的影响也逐渐受到关注。为了研究表面积的增加和不同的颗粒形状如何影响药物释放和细胞活力，开发了一种新方法来生产具有可调节圆度的球形水凝胶颗粒，旨在调节药物输送。为此，水凝胶前体的液滴被挤压在两个带有间隔物的超疏水表面之间，间隔物的高度不同，然后用光交联来保持“去夹层”后获得的形状。进行了数值模拟研究，以研究聚合物液滴几何变形过程，该过程与实验获得的结果一致。使用甲基丙烯酰化壳聚糖在温和的条件下生产出球形颗粒，能够包封蛋白质或细胞。由于与球形相比，其具有更高的表面积与体积比，因此，由于核心处营养物质扩散增强，球形颗粒中的包封细胞的活力得到提高，并且导致聚合物网络中的药物释放速度显著加快。这些结果也通过数值评估进行了评估，其中计算了不同类球形几何形状的药物释放速率。因此，所描述的方法可用于制造具有定制几何形状的球形颗粒，可广泛应用于生物医学领域，包括药物输送或作为细胞封装平台。
