Background Hypertrophic scars are skin fibrotic diseases, characterized by fibroblast hyperproliferation and excessive accumulation of extracellular matrix. However, topical drug application for hypertrophic scars are unsatisfactory. The purpose of this study was to explore the permeability of silk nanofiber hydrogels (SNFs) loaded with rhodamine 6G (R6G) and rhodamine 110 (R110) mediated by CO2 fractional laser irradiation into hypertrophic scar tissues. Methods In this work, R6G and R110 were chosen as hydrophilic and hydrophobic model molecules. They were loaded inside SNFs. In vivo rabbit ear hypertrophic scars were treated with CO2 fractional laser irradiation and then R6G/R110-laden SNFs were applied to the scars to evaluate their synergetic effect on drug penetration efficiency. Their permeability was quantified by fluorescence intensity and measured by confocal laser scanning microscopy on days 1, 3, 5 and 7. More specifically, the thermal coagulation zone (CZ) and its surrounding area (peri-CZ) caused by the thermal coagulation of the laser were discussed separately. Results Our data indicated that the SNFs promoted the penetration of R6G but not that of R110 in the peri-CZ on day 1 when combined with laser irradiation. Interestingly, both R6G and R110 were abundant in the CZ and remained stable on days 1, 3 and 5. Moreover, rapid re-epithelialization hindered the long-term permeability of both drugs. Conclusion Combining CO2 fractional laser irradiation with SNF drug delivery could improve the efficiency of hydrophilic drug delivery within 24 h before total re-epithelialization.

中文翻译：

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CO2点阵激光辅助丝纳米纤维载体透皮递送兔耳增生性疤痕模型

背景 肥厚性疤痕是皮肤纤维化疾病，其特征是成纤维细胞过度增殖和细胞外基质过度积累。然而，对于增生性疤痕的局部药物应用效果并不令人满意。本研究的目的是探讨 CO2 点阵激光照射下负载罗丹明 6G (R6G) 和罗丹明 110 (R110) 的丝纳米纤维水凝胶 (SNF) 对肥厚性疤痕组织的渗透性。方法本工作选择R6G和R110作为亲水和疏水模型分子。它们被加载到 SNF 中。采用 CO2 点阵激光照射治疗体内兔耳肥厚性疤痕，然后将载有 R6G/R110 的 SNF 应用于疤痕，以评估它们对药物渗透效率的协同作用。它们的渗透性通过荧光强度进行量化，并在第 1、3、5 和 7 天通过共焦激光扫描显微镜进行测量。更具体地说，由热凝固引起的热凝固区 (CZ) 及其周围区域 (peri-CZ)激光单独讨论。结果我们的数据表明，在第一天，当与激光照射相结合时，SNF 促进了 R6G 的渗透，但没有促进 R110 在 CZ 周围的渗透。有趣的是，R6G 和 R110 在 CZ 中含量丰富，并在第 1、3 和 5 天保持稳定。此外，快速的上皮再形成阻碍了两种药物的长期渗透性。结论 CO2点阵激光照射与SNF药物递送相结合可以提高完全上皮化前24小时内亲水性药物递送的效率。