Faraz Muhammad, Abbasi Muhammad Awais, Sang Pilgyu, Son Donghee, Baac Hyoung Won
Department of Electrical and Computer Engineering, Sungkyunkwan University, Suwon 16419, Korea.
Micromachines (Basel). 2020 Jun 28;11(7):631. doi: 10.3390/mi11070631.
Considerable attention has been devoted to the development of nanomaterial-based photoacoustic transmitters for ultrasound therapy and diagnosis applications. Here, we fabricate and characterize candle-soot nanoparticles (CSNPs) and polydimethylsiloxane (PDMS) composite-based photoacoustic transmitters, based on a solution process, not just to achieve high-frequency and high-amplitude pressure outputs, but also to develop physically stretchable ultrasound transmitters. Owing to its non-porous and non-agglomerative characteristics, the composite exhibits unique photo-thermal and mechanical properties. The output pressure amplitudes from CSNPs-PDMS composites were 20-26 dB stronger than those of Cr film, used as a reference. The proposed transmitters also offered a center frequency of 2.44-13.34 MHz and 6-dB bandwidths of 5.80-13.62 MHz. Importantly, we characterize the mechanical robustness of CSNPs-PDMS quantitatively, by measuring laser-damage thresholds, to evaluate the upper limit of laser energy that can be ultimately used as an input, i.e., proportional to the maximum-available pressure output. The transmitters could endure an input laser fluence of 54.3-108.6 mJ·cm. This is 1.65-3.30 times higher than the Cr film, and is significantly higher than the values of other CSNPs-PDMS transmitters reported elsewhere (22-81 mJ·cm). Moreover, we characterized the strain-dependent photoacoustic output of a stretchable nanocomposite film, obtained by delaminating it from the glass substrate. The transmitter could be elongated elastically up to a longitudinal strain of 0.59. Under this condition, it maintained a center frequency of 6.72-9.44 MHz, and 6-dB bandwidth ranges from 12.05 to 14.02 MHz. We believe that the stretchable CSNPs-PDMS composites would be useful in developing patch-type ultrasound devices conformally adhered on skin for diagnostic and therapeutic applications.
人们对用于超声治疗和诊断应用的基于纳米材料的光声发射器的开发给予了相当大的关注。在此，我们基于溶液法制备并表征了基于蜡烛烟灰纳米颗粒（CSNPs）和聚二甲基硅氧烷（PDMS）复合材料的光声发射器，不仅是为了实现高频和高振幅压力输出，还为了开发可物理拉伸的超声发射器。由于其无孔和非团聚的特性，该复合材料展现出独特的光热和机械性能。CSNPs - PDMS复合材料的输出压力振幅比用作参考的Cr膜强20 - 26 dB。所提出的发射器还具有2.44 - 13.34 MHz的中心频率和5.80 - 13.62 MHz的6 dB带宽。重要的是，我们通过测量激光损伤阈值来定量表征CSNPs - PDMS的机械鲁棒性，以评估最终可作为输入使用的激光能量上限，即与最大可用压力输出成正比。这些发射器能够承受54.3 - 108.6 mJ·cm²的输入激光通量。这比Cr膜高1.65 - 3.30倍，并且显著高于其他地方报道的其他CSNPs - PDMS发射器的值（22 - 81 mJ·cm²）。此外，我们表征了通过从玻璃基板上分层获得的可拉伸纳米复合膜的应变依赖光声输出。该发射器可弹性伸长至纵向应变为0.59。在此条件下，它保持6.72 - 9.44 MHz的中心频率，6 dB带宽范围为12.05至14.02 MHz。我们相信，可拉伸的CSNPs - PDMS复合材料将有助于开发用于诊断和治疗应用的贴合在皮肤上的贴片式超声设备。
