Design And Preparation Of Silicon Nanoparticles And Application Of Detecting Heavy Metals As Well As Visualization Of Latent Fingerprints

Silicon nanoparticles?Si NPs?possess well photoelectric performance,biocompatibility,lower toxicity and easily chemical surface-modification which acquire great concern.In this paper,folic acid,uric acid and safranine T were used as reducing agents and 3-amopropyl trimethoxysilane as silicon source to prepare Si NPs by liquid phase reduction method.Herein,we design fluorescent Si NPs as probe for detecting metal ions and exploite as agent for latent fingerprint imaging.The work described in this dissertation including the following three aspects:Si NPs were synthesized simply by facile mixing the reagents 3-amopropyl trimethoxysilane and folic acid under room temperature for 30 min.Fluorescence spectra of Si NPs showed maximum excitation and emission wavelengths at 370 nm and450 nm,respectively.Si NPs can be selectively and efficiently quenched by the Hg²⁺and Ag⁺,with detection limit of 2.676?M and 0.457?M.The sensing ability of Si NPs was successfully carried out in real water samples.Si NPs solutions and powders were also successfully employed as a promising fluorescent label for the visualization of latent fingerprints.In addition,Si NPs showed little effect on cell activity and had good cell permeability.The Si NPs was prepared through a simple solution-phase reductive strategy at a gentle condition with 3-amopropyl trimethoxysilane and uric acid used as raw materials.The as-prepared Si NPs exhibited emission at 425 nm with the excitation of 345 nm.The fluorescence and color change of the Si NPs induced by Cu²⁺and Mn²⁺exhibited sharp contrast.The limit of detection was 0.562?M(Cu²⁺),1.02?M(Mn²⁺)and 0.64?M(Cu²⁺),0.532?M(Mn²⁺).The Si NPs was successfully applied to effectively detect Cu²⁺and Mn²⁺in real samples.Interestingly,the Si NPs based gel membrane was also established to be selective for visual recognition of Cu²⁺and Mn²⁺.And cell imaging experiment revealed that the Si NPs possessed excellent biocompatibility and low cytotoxicity in living cells.Additionally,the powder of Si NPs was exploited to visualize latent fingerprints with good performance.These results indicated that the Si NPs can be applied in cell imaging due to they had low cytotoxicity on cell activity and good cell permeability.The Si NPs were synthesized by reduce the 3-amopropyl trimethoxysilane using safranine T as reducing agent.Notably,the fluorescence emission of Si NPs exhibited great evolution when extended to different solvents.The fluorescence emission wavelengths of Si NPs can be tuned by adjustment of the solvents,which is called solvatochromism.Based on this solvent-color effect,we obtained various kinds of Si NPs?Si NPs,Si NPs-A,Si NPs-B,Si NPs-C and Si NPs-D?which exhibited different fluorescence emission.It is worth noting that,the Si NPs-A exhibited excellent analytical sensing ability of Cu²⁺ions with fluorescent response from green to intense blue light.What's more,the excellent sensitivity of Si NPs-A towards Cu²⁺has been testified by the detection limit as low as 0.913?M.Due to the characteristic dual emission,Si NPs-A can be exploited as a dual-fluorescence visual agent for latent fingerprint imaging.These developed fingerprints clearly revealed the second-level details with high contrast and low background interference.