用金纳米棒修饰的亚微米光纤定点输送微颗粒的研究

Position Designated Delivery of Microparticles Using a Submicron Fiber Decorated with Gold Nanorods

通过热熔拉法将单模光纤拉制成亚微米尺寸的光纤,并借助光学显微镜的定位作用,在亚微米光纤的特定位置沉积金纳米棒(长度和中截面直径分别为80nm和20nm)。利用光纤倏逝波激发金纳米棒的局域表面等离波子共振(LSPR)。由于强的共振吸收和光热效应,当激光功率增加到30mW时,亚微米光纤上沉积金纳米棒的位置会产生一个微米尺寸的气泡,激光在该位置将被等离波子共振吸收和气泡散射掉,在气泡后面位置的光纤中观察不到光的传输。靠近光纤的900nm的聚苯乙烯颗粒被倏逝波所产生的梯度力捕获到光纤表面,并在散射力的作用下沿着光的传播方向运动,当颗粒运动到气泡位置时,将会停止向前运动。该技术可用于微米颗粒的定点输送。

The submicron fiber is fabricated by drawing a single-mode optical fiber through a flame-heated treatment. Gold nanorods （length and middle-section diameter are 80 nm and 20 nm, respectively） are deposited on the designated position of the submicro fiber by the positioning function of optical microscope, and the local surface plasmon resonance （LSPR） of gold nanorods is excited by the evanescent wave around the fiber. When the optical power increases to 30 mW, due to strong plasmon absorption and photothermal conversion, a microbubble forms at the position of the fiber decorated with the gold nanorods. Therefore, the laser light at this position is absorbed by plasmon resonance and scattered by the bubble. Optical transmission is not observed behind the bubble. Polystyrene particles （900 nm in diameter） near the fiber can be trapped by the gradient force, and then delivered along the direction of light propagation due to the scattering force induced by the evanescent wave. Once the particles move to the position of the bubble, they will stop their advancing. This technology can be used for targeted delivery of microparticles.