| Diseases seriously endanger human health and life,and the development of sensors for precise diagnosis and treatment of various diseases has received extensive attention from all walks of life.Rapid diagnostic methods can inhibit the spread of infectious diseases and are the main method to control epidemic outbreaks such as novel coronavirus pneumonia(COVID-19).In addition,precise diagnosis and treatment can also provide personalized treatment plans,which is an important method to improve the survival rate of major diseases such as tumors.However,the existing sensors have problems such as time-consuming,low sensitivity and large side effects in disease diagnosis and treatment.Optical fiber sensors have the advantages of miniaturization,simple optical path and strong anti-interference ability.Changing the shape can improve the sensitivity of the optical fiber sensor,which strongly promotes the application of optical fiber sensors in medical and health fields.Localized surface plasmon resonance(LSPR)is a real-time label-free technology that can efficiently convert light energy into heat energy,and is a cutting-edge photothermal therapy(PTT)technology.Based on this,this paper creatively combines a Ω-shaped optical fiber sensor with LSPR to develop a sensor for rapid detection of novel coronavirus(SARS-Co V-2)by designing a T-shaped aptamer,and systematically studys the photothermal properties of optical fiber LSPR to construct a high-sensitivity,low-toxicity dual-function sensor for diagnosis and treatment.The main research contents of this paper are as follows:(1)By innovatively designing a T-shaped aptamer to improve the binding affinity with N protein,a Ω-shaped optical fiber based on aptamer sensor was constructed,which solved the problem of long time-consuming detection of SARS-Co V-2.T-shaped aptamers can effectively regulate the orientation and density of aptamers on the surface of gold nanoparticles(Au NPs),and their affinity is significantly improved compared with the existing poly A and thiol modified aptamers.T-shaped aptamer-functionalized Ω-shaped optical fiber can be used to construct a direct analysis method;the introduction of aptamer-functionalized gold/silver nanoparticles(Au/Ag NPs-apt)can further amplify the LSPR signal,and a sandwich analysis method was developed.The sensor was successfully applied to the detection of clinical samples from nasopharyngeal swabs.Within a detection time of 45 min,the Ω-shaped fiber optic sensor could correctly distinguish between COVID-19 patients and healthy volunteers,with a true positive detection rate of 93.8% and a true negative detection rate of 100%.In addition,the sensor also enables one-step,rapid analysis of N protein in cold chain foods.The LSPR aptamer sensor based on Ω-shaped optical fiber can rapidly detect SARS-Co V-2,providing a potential new method for the rapid detection of infectious diseases.(2)By introducing photothermal material gold nanorods(Au NRs)with LSPR effect,a hybrid nanolayer-functionalized optical fiber LSPR was prepared,and a dual-function sensor for cell detection and photothermal therapy(PTT)was creatively developed.Through Au NRs ligand replacement,Au NPs/Au NRs functionalized Ω-shaped optical fiber LSPR was prepared,and ultrasensitive analysis of tumor cells was achieved with a LOD as low as 2.6 cells/m L.By monitoring the heating curve,it was found that the Ω-shaped optical fiber LSPR had localized,high-efficiency and structure-dependent heat generation characteristics.This feature can effectively kill the cells bound to the surface of the optical fiber without damage to non-specific cells.Under the continuous irradiation of near-infrared laser,the sensor can kill 81.8% of the target MCF-7 cells through the PTT effect,and the killing rate of non-target cells was less than20%.In summary,the constructed LSPR sensor based on Ω-shaped optical fiber has the advantages of high sensitivity,high heat generation efficiency,and low side effects,and is expected to be a promising tool for tumor diagnosis and treatment. |
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