PDF(Pubmed)
Abstract：
Photothermal conversion of light into heat energy is an intrinsic optical property of metal nanoparticles when irradiated using near-infrared radiation. However, the impact of size and shape on the photothermal behaviour of gold nanomakura particles possessing optical absorption within 600-700 nm as well as on incorporation in hydrogels is not well reported. In this study, nanomakura-shaped anisotropic gold nanoparticles (AuNMs) were synthesized via a surfactant-assisted seed-mediated protocol. Quaternary cationic surfactants having variable carbon tail length (n = 16, 14, 12) were used as capping for tuning the plasmon peak of gold nanomakura within a 600-700 nm wavelength. The aspect ratio as well as anisotropy of synthesized gold nanomakura can influence photothermal response upon near-infrared irradiation. The role of carbon tail length was evident via absorption peaks obtained from longitudinal surface plasmon resonance analysis at 670, 650, and 630 nm in CTAB-AuNM, MTAB-AuNM, and DTAB-AuNM, respectively. Furthermore, the impact of morphology and surrounding milieu of the synthesized nanomakuras on photothermal conversion is investigated owing to their retention of plasmonic stability. Interestingly, we found that photothermal conversion was exclusively assigned to morphological features (i.e., nanoparticles of higher aspect ratio showed higher temperature change and vice versa irrespective of the surfactant used). To enable biofunctionality and stability, we used kappa-carrageenan- (k-CG) based hydrogels for incorporating the nanomakuras and further assessed their photothermal response. Nanomakura particles in association with k-CG were also able to show photothermal conversion, depicting their ability to interact with light without hindrance. The CTAB-AuNM, MTAB-AuNM, and DTAB-AuNM after incorporation into hydrogel beads attained up to ≈17.2, ≈17.2, and ≈15.7 °C, respectively. On the other hand, gold nanorods after incorporation into k-CG did not yield much photothermal response as compared to that of AuNMs. The results showed a promising platform to utilize nanomakura particles along with kappa-carrageenan hydrogels for enabling usage on nanophotonic, photothermal, and bio-imaging applications.
摘要：
当使用近红外辐射照射时,光到热能的光热转化是金属纳米颗粒的固有光学性质。然而,尺寸和形状对在600-700nm范围内具有光吸收的纳米金颗粒的光热行为以及在水凝胶中的掺入的影响没有得到很好的报道。在这项研究中,nanomakura形各向异性金纳米颗粒（AuNMs）通过表面活性剂辅助种子介导的方案合成。具有可变碳尾长度（n=16、14、12）的四元阳离子表面活性剂用作封端，以调节纳米金的等离子体峰在600-700nm波长内。合成的金nanomakura的纵横比和各向异性会影响近红外辐照时的光热响应。通过CTAB-AuNM中670、650和630nm处的纵向表面等离子体共振分析获得的吸收峰，碳尾长度的作用很明显，MTAB-AuNM,和DTAB-AuNM，分别。此外，由于保留了等离子体的稳定性，研究了合成的nanomakuras的形态和周围环境对光热转化的影响。有趣的是,我们发现光热转换被专门分配给形态特征(即，高宽比的纳米颗粒显示出更高的温度变化，反之亦然，而与使用的表面活性剂无关）。为了实现生物功能和稳定性，我们使用基于kappa-角叉菜胶-（k-CG）的水凝胶掺入nanomakuras，并进一步评估其光热响应。与k-CG结合的Nanomakura颗粒也能够显示光热转化，描绘了它们与光相互作用而不受阻碍的能力。CTAB-AuNM,MTAB-AuNM,和DTAB-AuNM掺入水凝胶珠后达到约17.2，约17.2和约15.7°C，分别。另一方面,与AuNMs相比，掺入k-CG后的金纳米棒并没有产生多少光热响应。结果显示了一个有希望的平台，可以利用nanomakura颗粒和κ-角叉菜胶水凝胶来实现纳米光子的使用，光热,和生物成像应用。
