حسگر زيستي مبتني بر تحريك پلاسمون پلاريتونهاي سطحي: بررسي، مقايسه و بهينه سازي

در اﯾﻦ ﻣﻘﺎﻟﻪ ﺣﺴﮕﺮ زﯾﺴﺘﯽ ﺑﺮ ﭘﺎﯾﻪ ﺗﺤﺮﯾﮏ ﭘﻼﺳﻤﻮن ﭘﻼرﯾﺘﻮن ﺳﻄﺤﯽ ﺷﺎﻣﻞ ﻓﻠﺰات ﭘﻼﺳﻤﻮﻧﯿﮏ ﻃﻼ و ﻧﻘﺮه ﺑﺼﻮرت ﺗﺌﻮري ﻣﻮرد ﺑﺮرﺳﯽ ﻗﺮار ﮔﺮﻓﺖ. ﺷﺒﯿﻪﺳﺎزيﻫﺎ ﺑﻮﺳﯿﻠﻪ ﻧﺮم اﻓﺰار ﻣﺘﻠﺐ و ﺑﺮ اﺳﺎس روش ﻣﺎﺗﺮﯾﺲﻫﺎي اﻧﺘﻘﺎل 4×4 اﻧﺠﺎم ﺷﺪه اﺳﺖ. اﺳﺎس ﻋﻤﻠﮑﺮد اﯾﻦ ﺣﺴﮕﺮ ﺑﺮ ﺣﺴﺐ ﻣﻘﺪار ﺟﺎﺑﺠﺎﯾﯽ در زاوﯾﻪ ﮐﻤﯿﻨﻪ ﺑﺎزﺗﺎب از ﺳﻄﺢ ﺳﺎﺧﺘﺎر ﺗﻌﺮﯾﻒ ﺷﺪ. ﺑﺎزﺗﺎب ﺳﺎﺧﺘﺎر ﺳﻪ ﻻﯾﻪ [ﺷﯿﺸﻪ/ﻓﻠﺰ ﭘﻼﺳﻤﻮﻧﯿﮏ/دياﻟﮑﺘﺮﯾﮏ] در ﺿﺨﺎﻣﺖﻫﺎي 10 ﺗﺎ 80 ﻧﺎﻧﻮﻣﺘﺮ ﺑﺮاي زواﯾﺎي ﺗﺎﺑﺸﯽ ﻣﺨﺘﻠﻒ ﻣﻮرد ﻣﺤﺎﺳﺒﻪ ﻗﺮار ﮔﺮﻓﺖ و ﺿﺨﺎﻣﺖ ﺑﻬﯿﻨﻪ ﺑﺮاي داﺷﺘﻦ ﺑﯿﺸﯿﻨﻪ ﺗﺤﺮﯾﮏ ﭘﻼﺳﻤﻮن ﺳﻄﺤﯽ ﺑﺪﺳﺖ آورده ﺷﺪ. ﮐﻤﯿﻨﻪ ﺑﺎزﺗﺎب ﺑﻪ ﺗﺮﺗﯿﺐ در ﺿﺨﺎﻣﺖﻫﺎي 45 و 47/5 ﻧﺎﻧﻮﻣﺘﺮ ﺑﺮاي ﺳﺎﺧﺘﺎرﻫﺎي ﺷﺎﻣﻞ ﻃﻼ و ﻧﻘﺮه ﺑﺪﺳﺖ آﻣﺪ و ﺳﭙﺲ ﻗﺪرت ﺣﺴﮕﺮي اﯾﻦ ﺳﺎﺧﺘﺎر در ﺿﺨﺎﻣﺖ ﺑﻬﯿﻨﻪ ﻣﻮرد ﺑﺮرﺳﯽ دﻗﯿﻖﺗﺮ ﻗﺮار ﮔﺮﻓﺖ. در ﺳﺎﺧﺘﺎر [ﺷﯿﺸﻪ/ﻃﻼ/ﺧﻮن] ﺑﻪ ازاي 0/01 ﺗﻐﯿﯿﺮ در ﺿﺮﯾﺐ ﺷﮑﺴﺖ ﺑﻪ ﻣﻘﺪار 1/8 درﺟﻪ در ﮐﻤﯿﻨﻪ ﺑﺎزﺗﺎب ﺟﺎﺑﺠﺎﯾﯽ ﻣﺸﺎﻫﺪه ﻣﯽﺷﻮد ﮐﻪ اﯾﻦ ﻣﻘﺪار ﺑﺮاي ﺣﺴﮕﺮ ﻧﻘﺮه ﺑﺮاﺑﺮ ﺑﺎ 1/37 درﺟﻪ ﺑﺪﺳﺖ آﻣﺪ. ﻧﺘﺎﯾﺞ ﻧﺸﺎن دادﻧﺪ ﮐﻪ ﺑﺮاي ﻣﺎده زﯾﺴﺘﯽ ﺧﻮن، ﺣﺴﮕﺮ ﺷﺎﻣﻞ ﻓﻠﺰ ﭘﻼﺳﻤﻮﻧﯿﮏ ﻃﻼ دﻗﺖ ﻗﺎﺑﻞ ﻗﺒﻮﻟﯽ دارد ﮐﻪ ﻣﯽﺗﻮاﻧﺪ ﺑﻪ ﻋﻨﻮان ﯾﮏ ﺣﺴﮕﺮ زﯾﺴﺘﯽ ﺳﺎده ﺑﺎ دﻗﺖ ﺑﺎﻻ ﭘﯿﺸﻨﻬﺎد ﺷﻮد

In this paper, bio-sensors based on surface plasmon polariton, including plasmonic metals, such as gold and silver have been theoretically investigated. The numerical simulations were carried out using MATLAB software based on 4×4 transfer matrix method (TMM). The functional principle of the sensing system is based on the shift in the minimum of reflectivity in [Glass / Plasmonic metal / Dielectric] structure. For obtaining the surface plasmon polariton resonant excitation, the reflectivity of structure in the thicknesses of 10 to 80 nanometer of plasmonic metal is calculated and optimum thicknesses have been found. In simulations, for gold and silver thin films, the minimum of reflectivity in thicknesses of 45 and 47.5 nm were obtained, respectively. In the following, sensitivity in optimum thicknesses has been investigated with more details. [Glass /Au / Blood] and [Glass / Ag / Blood] biosensors were shown 1.8 and 1.37 degree shift in minimum reflection for each 0.01 change in refractive index of blood, respectively. These numerical results have proved that for gold included blood bio-sensor has an acceptable sensitivity which can be considered as a simple high sensitive bio-sensor.