王培龍 唐智勇
摘要: 納米材料具有特殊的尺寸效應(yīng)和優(yōu)異的光電性質(zhì),已在傳感分析中得到高度重視和廣泛應(yīng)用,大幅提高了傳感分析技術(shù)的性能。近年來,智慧農(nóng)業(yè)發(fā)展迅速,農(nóng)產(chǎn)品質(zhì)量安全作為農(nóng)業(yè)生產(chǎn)的重要組成部分,對(duì)農(nóng)業(yè)傳感技術(shù)的靈敏度、穩(wěn)定性和檢測(cè)通量等指標(biāo)要求越來越高。本綜述簡(jiǎn)要闡述了幾種常用的納米材料的性質(zhì)和特點(diǎn),包括碳基納米材料、金屬納米材料和金屬-有機(jī)框架材料等。重點(diǎn)論述了基于納米材料的化學(xué)傳感、生物傳感、電化學(xué)傳感和光譜傳感等常用傳感分析技術(shù)和器件,以及納米傳感分析技術(shù)在農(nóng)產(chǎn)品質(zhì)量安全,尤其在克倫特羅和三聚氰胺等危害物,甲硝唑、二噁英類化合物,違禁添加物,真菌毒素,鋅、鎘、鉛等目標(biāo)物,丙烯酰胺、呋喃類、硝基呋喃類抗生素監(jiān)測(cè)等方面的應(yīng)用。納米材料的制備和修飾技術(shù)扔需要進(jìn)一步提升,多目標(biāo)、高通量納米傳感器件在實(shí)際應(yīng)用中的價(jià)值廣受關(guān)注,在線傳感分析在農(nóng)產(chǎn)品質(zhì)量安全智慧監(jiān)控方面有迫切需求需要快速、實(shí)時(shí)、在線監(jiān)測(cè)。
關(guān)鍵詞: 納米材料;智慧農(nóng)業(yè);農(nóng)產(chǎn)品質(zhì)量安全;納米傳感器
中圖分類號(hào): S951.4+2; S-1 文獻(xiàn)標(biāo)志碼: A 文章編號(hào): 202003-SA003
引文格式:王培龍, 唐智勇. 農(nóng)產(chǎn)品質(zhì)量安全納米傳感應(yīng)用研究分析與展望[J]. 智慧農(nóng)業(yè)(中英文), 2020, 2(2): 1-10.
1 引 ?言
智慧農(nóng)業(yè)是農(nóng)業(yè)發(fā)展從數(shù)字化到網(wǎng)絡(luò)化再到智能化的高級(jí)階段,對(duì)農(nóng)業(yè)具有里程碑意義,已成為世界現(xiàn)代農(nóng)業(yè)發(fā)展趨勢(shì),也成為發(fā)展中國(guó)家消除貧困的重要途徑。傳感技術(shù)在智慧農(nóng)業(yè)中扮演了重要角色,是智慧農(nóng)業(yè)的核心與關(guān)鍵。未來國(guó)際農(nóng)業(yè)傳感技術(shù)的突破和顛覆主要集中在動(dòng)植物生命信息捕獲、種養(yǎng)殖加工儲(chǔ)運(yùn)環(huán)境信息傳感和農(nóng)產(chǎn)品質(zhì)量安全傳感等幾個(gè)方面[1]。
隨著物質(zhì)生活的極大豐富,消費(fèi)者對(duì)高品質(zhì)農(nóng)產(chǎn)品的需求日益增長(zhǎng),農(nóng)產(chǎn)品質(zhì)量安全傳感分析技術(shù)也越來越受到重視。影響農(nóng)產(chǎn)品質(zhì)量安全的危害因子主要有人為因素(如非法添加、農(nóng)藥和獸藥使用等)、自然污染(如真菌毒素、致病微生物等)和環(huán)境遷移(如重金屬、持久性有機(jī)污染物等)[2]。這些危害因素種類多、危害性強(qiáng)且含量低,而農(nóng)產(chǎn)品具有“鮮活”特性,對(duì)保障其質(zhì)量安全傳感分析技術(shù)的靈敏度、穩(wěn)定性和選擇性等性能指標(biāo)和可操作性、實(shí)用性等提出了更高要求?,F(xiàn)有農(nóng)產(chǎn)品質(zhì)量安全傳感分析技術(shù)難以滿足現(xiàn)代農(nóng)業(yè)的需求。
納米傳感器是一種具有納米尺度特征尺寸的傳感器,有無損性、微創(chuàng)性和實(shí)時(shí)性等特點(diǎn),已成為農(nóng)業(yè)生產(chǎn)中營(yíng)養(yǎng)管理、疾病評(píng)估、食品生產(chǎn)、DNA/蛋白質(zhì)檢測(cè)和植物激素調(diào)控等的重要工具[3]。納米材料的出現(xiàn)為農(nóng)產(chǎn)品質(zhì)量安全傳感分析性能提升和改進(jìn)提供了新機(jī)遇。由于納米材料特殊的尺寸效應(yīng)、表面效應(yīng)和宏觀量子隧道效應(yīng),顯示出光學(xué)、熱學(xué)、電學(xué)、磁學(xué)、力學(xué)以及化學(xué)方面的特殊性質(zhì)。納米材料的這些特性對(duì)于改進(jìn)和提升農(nóng)產(chǎn)品質(zhì)量安全傳感分析性能具有重要意義。目前,碳基納米材料、貴金屬納米材料以及金屬有機(jī)框架等納米結(jié)構(gòu)材料等已在構(gòu)筑高性能農(nóng)產(chǎn)品質(zhì)量安全納米傳感器件方面廣泛應(yīng)用,表現(xiàn)出極為優(yōu)異的性能。
本文重點(diǎn)圍繞農(nóng)產(chǎn)品質(zhì)量安全傳感分析技術(shù)進(jìn)行綜述,首先簡(jiǎn)要介紹納米材料的類別和性質(zhì),然后重點(diǎn)論述納米材料在農(nóng)產(chǎn)品質(zhì)量安全傳感分析技術(shù),如化學(xué)傳感、生物傳感、電化學(xué)傳感以及光譜傳感中的應(yīng)用。最后,對(duì)納米材料在農(nóng)產(chǎn)品質(zhì)量安全傳感分析中的應(yīng)用進(jìn)行了總結(jié)和展望。
2 納米材料及其性質(zhì)
納米材料主要包括納米尺寸材料和納米結(jié)構(gòu)材料,具體是指在三維空間中至少有一維處于納米尺寸(0.1~100 nm)或由它們作為基本單元構(gòu)成的材料。由于納米材料的尺寸、表面和宏觀量子隧道等效應(yīng),使其具有特殊的光、電、磁等理化性質(zhì),在組裝傳感器件方面具有特定優(yōu)勢(shì)。目前,在納米傳感中常用的納米材料包括碳基納米材料(Carbon-based Nanomaterials,CNMs)、金屬納米材料和金屬-有機(jī)框架材料(Metal-Organic Frameworks,MOFs)等。
CNMs是一類工程納米材料,因其優(yōu)異的光、電、機(jī)械和熱性能,在能源、催化、環(huán)境和生命科學(xué)等領(lǐng)域得到了廣泛應(yīng)用[4]。繼1985年發(fā)現(xiàn)富勒烯(C60)碳納米材料后,1991年發(fā)現(xiàn)碳納米管(CNT),2004年發(fā)現(xiàn)石墨烯和碳量子點(diǎn)。目前,這些碳納米材料作為傳感器的信號(hào)放大和傳輸單元,已在環(huán)境監(jiān)測(cè)、食品安全等領(lǐng)域得到了很好的應(yīng)用[5,6]。
近幾十年來,納米科學(xué)和技術(shù)的迅速發(fā)展促進(jìn)了對(duì)金屬納米材料的合成、性能和應(yīng)用的深入研究[7]。大量具有明確尺寸、形狀和組成的金屬和合金納米材料已被合成用于電子、催化和生物醫(yī)學(xué)等領(lǐng)域。特別是貴金屬納米材料,因其源于材料表面強(qiáng)電磁作用的光學(xué)特性更為引人注目,這些光學(xué)特性可用于構(gòu)筑可視化傳感和增強(qiáng)光譜信號(hào)[2]。
MOFs是一類具有均勻結(jié)構(gòu)的復(fù)雜化多孔材料,由于其高孔隙率和可調(diào)的物理和化學(xué)性質(zhì),被用于氣體和水儲(chǔ)存、氣體凈化、污染物去除和催化等領(lǐng)域。MOFs光譜、結(jié)構(gòu)等特性和豐富的活性基團(tuán),使其在傳感分析領(lǐng)域具有廣闊的應(yīng)用前景[8]。
3 農(nóng)產(chǎn)品質(zhì)量安全納米傳感及應(yīng)用
3.1 化學(xué)傳感
化學(xué)傳感器件是對(duì)各種化學(xué)物質(zhì)敏感并將其濃度轉(zhuǎn)換為電信號(hào)的器件,并進(jìn)行檢測(cè)。具有響應(yīng)速度快、靈敏度高等特點(diǎn),在環(huán)境監(jiān)測(cè)、食品安全和醫(yī)療診斷[9]等領(lǐng)域廣泛應(yīng)用。納米材料被集成到傳感系統(tǒng)中,具有更高的靈敏度、更短的檢測(cè)時(shí)間和更好的分析通量。如Liao等[10]研發(fā)了一種用于壓力/溫度/紫外檢測(cè)的高伸縮性ZnO纖維多功能納米傳感器,可以同時(shí)實(shí)現(xiàn)多指標(biāo)的傳感分析。Feng等[11]采用靜電紡絲工藝制備的非晶碳/還原氧化石墨烯(rGO)包裹的Co3O4納米纖維,能夠?qū)H3進(jìn)行選擇性傳感監(jiān)測(cè),有良好的靈敏度和快速響應(yīng)(約20 s,50 mg/L)能力,并具有長(zhǎng)達(dá)4年的長(zhǎng)期穩(wěn)定性。
化學(xué)傳感器件在農(nóng)產(chǎn)品質(zhì)量安全監(jiān)測(cè)中具有明顯的優(yōu)勢(shì),但是農(nóng)產(chǎn)品樣品基質(zhì)復(fù)雜且目標(biāo)物含量較低,因此需要選擇性的材料進(jìn)行識(shí)別。分子印跡聚合物(Molecular Imprinted Polymer,MIP)是一種良好的識(shí)別材料,結(jié)合納米標(biāo)記材料能夠開發(fā)一系列化學(xué)傳感器?;贛IP包被CdTe量子點(diǎn)(MIP-CdTeQDs),Huy等[12]建立了一種克倫特羅和三聚氰胺等危害物的傳感分析新方法,其檢測(cè)限為120 ng/mL。通過對(duì)牛奶和動(dòng)物肝臟樣品中克倫特羅和三聚氰胺的檢測(cè)分析,評(píng)價(jià)了該方法在實(shí)際樣品中的可行性,回收率為92%~97%。特別是MIP-CdTeQDs傳感器件可以很容易地再生,用于后續(xù)的樣品分析。同樣,Tang等[13]提出了一種基于MIPs和上轉(zhuǎn)換發(fā)光納米材料(UCP)的光譜傳感器制作新策略(見圖1)。他們合成了一種基于UCPs(YF3:Yb3+或Er3+)的MIPs@UCPs上轉(zhuǎn)換發(fā)光探針,通過分子印跡聚合物(MIPs@UCPs)對(duì)目標(biāo)物進(jìn)行了選擇性識(shí)別,依據(jù)發(fā)光強(qiáng)度變化實(shí)現(xiàn)對(duì)目標(biāo)物的傳感分析,對(duì)克倫特羅的檢測(cè)限低于0.12 μg/L。Mehrzad-Samarin等[14]報(bào)道了一種用于檢測(cè)生物樣品中甲硝唑的新型光學(xué)納米傳感器合成了石墨烯量子點(diǎn)嵌入二氧化硅分子印跡聚合物(GQDs-embedded-SMIP)作為甲硝唑選擇性熒光探針。新合成的嵌入SMIP的量子點(diǎn)在450 nm處有較強(qiáng)的熒光發(fā)射,在365 nm處激發(fā),在甲硝唑作為模板分子存在下猝滅,猝滅效率與甲硝唑濃度成正比,檢測(cè)限為0.15 μmol/L。
納米材料的性質(zhì)以及與目標(biāo)分析物的特異作用,也能提高化學(xué)傳感的穩(wěn)定性和選擇性。近年來,中國(guó)農(nóng)業(yè)科學(xué)院“飼料質(zhì)量安全檢測(cè)與評(píng)價(jià)”研究團(tuán)隊(duì)?wèi)?yīng)用多孔發(fā)光MOFs材料創(chuàng)制了系列可再生納米傳感新材料,如創(chuàng)制了一種高穩(wěn)定的鋯基MOF材料Zr6O4(OH)8(HCOO)2(CPTTA)2,(BUT-17)該MOF材料具有一維六邊形通道和富含苯基的孔表面,用于識(shí)別和傳感兩種具有代表性二噁英類化合物,多氯二苯并二噁英(BCDD)和2,3,7,8-四氯二苯并二噁英(TCDD)。基于二噁英類化合物對(duì)BUT-17的熒光猝滅研制了傳感新器件,其對(duì)BCDD和TCDD的檢測(cè)限分別為27 μg/L和57 μg/L,且具有很強(qiáng)的選擇性,不受類似化合物的干擾[15]。類似地,團(tuán)隊(duì)還建立了違禁添加物[16]和禁限用藥物[17]的傳感方法。另外,Qiu等[18]將硝基苯基引入一種能形成多孔晶體帶的三氟芴分子中,研制了一種新型的高靈敏度鄰苯二甲酸酯(塑化劑)熒光傳感器。在單晶分析和理論計(jì)算的基礎(chǔ)上,證明了鄰苯二甲酸酯分子可以通過非共價(jià)相互作用擴(kuò)散到晶體帶的空穴中,有效地抑制硝基苯基的旋轉(zhuǎn),從而增強(qiáng)了發(fā)射。由于這種新的響應(yīng)機(jī)制,鄰苯二甲酸酯的熒光檢測(cè)具有高靈敏度,鄰苯二甲酸二(2-乙基己基)酯(DEHP)的檢測(cè)限為0.03 μg/L,而且該納米傳感器具有快速可逆開啟的特點(diǎn),可用于食品包裝材料的在線監(jiān)測(cè)。
近年來,比色傳感器因其便于肉眼判定和簡(jiǎn)單操作而受到越來越多的關(guān)注。溶液中的金基納米材料(AuNMs)聚集或刻蝕后,在可見光區(qū)域呈現(xiàn)不同的顏色和光譜變化。利用AuNMs這一特性,通過目標(biāo)分析物與AuNMs表面的靜電作用和氫鍵等非共價(jià)力,實(shí)現(xiàn)目標(biāo)分析物的可視化傳感。這種比色傳感最大的優(yōu)點(diǎn)是無需設(shè)備,肉眼可判[19]。比色傳感已很好地用于醫(yī)學(xué)和食品安全領(lǐng)域中病毒[20]、DNA[21]、小分子[22]、金屬離子[23]和癌細(xì)胞[24]等目標(biāo)物的檢測(cè)。Zhou等[25]采用三聚氰胺修飾的金納米粒子(AuNPs)對(duì)萊克多巴胺和沙丁胺醇進(jìn)行了高選擇性和高靈敏度的比色檢測(cè)。此類β-激動(dòng)劑化合物的存在通過氫鍵作用誘導(dǎo)金納米粒子的聚集,伴隨著AuNPs溶液顏色和光學(xué)性質(zhì)的明顯變化,可通過肉眼對(duì)目標(biāo)物監(jiān)測(cè)。
3.2 生物傳感
生物傳感通常應(yīng)用生物識(shí)別單元如抗體、適配體等進(jìn)行組裝傳感器件,納米材料在生物傳感中主要起信號(hào)標(biāo)記和增強(qiáng)作用。目前,生物傳感器件已廣泛應(yīng)用于農(nóng)產(chǎn)品質(zhì)量安全中違禁添加物、真菌毒素等的監(jiān)測(cè)。AuNPs常用于標(biāo)記抗體來制作膠體金試紙條,在抗生素、β-受體激動(dòng)劑和黃曲霉毒素等的快速篩查和監(jiān)測(cè)中廣泛應(yīng)用[26]。如Wu等[27]應(yīng)用AuNPs結(jié)合金剛烷胺抗體建立了一種靈敏的膠體金免疫層析方法,用于快速半定量檢測(cè)雞肌肉中金剛烷胺,檢測(cè)時(shí)間為12 min,檢測(cè)限為1.80 ng/mL。Song等[28]應(yīng)用AuNPs和單克隆抗體建立一種高靈敏度、特異性的牛奶中常山酮(HFG)快速傳感分析方法,對(duì)牛奶中常山酮的檢出限為100 ng/mL,整個(gè)檢測(cè)過程可在5 min內(nèi)完成。
近年來,為了獲得更高的傳感靈敏度,一些新型納米標(biāo)記材料,如熒光納米材料和上轉(zhuǎn)換納米材料等,被應(yīng)用于生物傳感中抗體標(biāo)記。Ren等[29]應(yīng)用CdSe/ZnS發(fā)光量子點(diǎn)標(biāo)記抗體研究建立了玉米中黃曲霉毒素B1超高靈敏度傳感分析方法,檢測(cè)限為0.42 pg/mL,較常規(guī)AuNPs標(biāo)記方法的靈敏度提升2個(gè)數(shù)量級(jí)。Wang等[30]應(yīng)用熒光納米微球標(biāo)記單克隆抗體組裝了同時(shí)測(cè)定克倫特羅、萊克多巴胺和沙丁胺醇等3種“瘦肉精”類化合物的免疫層析傳感器,實(shí)現(xiàn)了從單一目標(biāo)向多目標(biāo)同時(shí)檢測(cè)的轉(zhuǎn)變。進(jìn)而結(jié)合高交叉反應(yīng)率抗體,研制出能夠同時(shí)測(cè)定7種“瘦肉精”類化合物的傳感分析方法[31]。為了消除樣品基質(zhì)干擾,提高檢測(cè)的準(zhǔn)確度,Wang等[32]利用上轉(zhuǎn)換發(fā)光(Up-conversion Phosphor,UCP)納米材料低能量激發(fā)和高能量發(fā)射的特性,建立了UCP納米微球標(biāo)記側(cè)流層析傳感器件,能夠?qū)?dòng)物性食品中瘦肉精類化合物克倫特羅進(jìn)行超敏檢測(cè)(見圖2)。由于UCP納米材料的光譜特性,很好地消除了復(fù)雜樣品基質(zhì)的干擾。
近年來,除傳統(tǒng)的抗體外,適配體的良好識(shí)別和選擇性結(jié)合能力也得到關(guān)注。針對(duì)農(nóng)產(chǎn)品中危害物,相關(guān)機(jī)構(gòu)應(yīng)用適配體結(jié)合納米材料,研發(fā)了系列生物傳感器件。Ma等[33]將鉑納米粒子(PtNPs)包埋在AFB1響應(yīng)性DNA水凝膠中,開發(fā)基于微壓傳感器平臺(tái)的AFB1便攜式生物傳感器。Hu等[34]選擇HKUST-1 MOF材料作為吸附劑制備Fe3O4/g-C3N4/HKUST-1復(fù)合納米材料,構(gòu)筑了赭曲霉毒素A(Ochratoxin,OTA)生物傳感器。因?yàn)镠KUST-1可以提高復(fù)合材料的化學(xué)穩(wěn)定性,并通過光誘導(dǎo)電子轉(zhuǎn)移(Photo-induced Electron Transfer,PET)完全熄滅OTA適配體上5-羧熒光素(FAM)染料的熒光。因此,在OTA存在下,識(shí)別適體可以與OTA結(jié)合,從Fe3O4/g-C3N4/HKUST-1復(fù)合物中釋放出相應(yīng)的FAM標(biāo)記的適體,從而使傳感系統(tǒng)的熒光強(qiáng)度逐漸恢復(fù)。反之,熒光被猝滅。該生物傳感器靈敏度達(dá)2.57 ng/mL。
3.3 電化學(xué)傳感
電化學(xué)(Electrical Conductivity,EC)傳感器是一種典型的具備微型化分析設(shè)備,通過測(cè)量電流等電化學(xué)信號(hào)的變化來檢測(cè)痕量的目標(biāo),包括有機(jī)小分子、金屬離子和生物分子。由于化學(xué)/生物分子在電極和電化學(xué)單元的作用下氧化/還原而產(chǎn)生的電壓、電位或阻抗信號(hào)。一般來說,電極的修飾主要是通過結(jié)合特定的識(shí)別元件來提高傳感器的選擇性,如適體、抗體和受體等[35]。目前,EC傳感在農(nóng)產(chǎn)品中危害物的檢測(cè)中越來越受到重視。
納米材料在提升EC傳感性能方面扮演著重要的角色。Rivas等[36]開發(fā)了一種基于IrO2納米顆粒的納米結(jié)構(gòu)平臺(tái),以提高EC的分析性能。在復(fù)雜樣品中檢測(cè)OTA時(shí),基質(zhì)背景干擾較低,說明了該方法在實(shí)際樣品分析中的有效性。作者團(tuán)隊(duì)?wèi)?yīng)用AuNPs和石墨烯開發(fā)了無標(biāo)記EC傳感新技術(shù),結(jié)合抗體和適配體,實(shí)現(xiàn)了對(duì)萊克多巴胺等養(yǎng)殖過程非法添加物的快速、高敏檢測(cè),檢測(cè)靈敏度為1.0×10-12 mol/L[37,38](見圖3)。Yang等[39]報(bào)道了一種基于量子點(diǎn)發(fā)光EC傳感器,通過外切酶催化靶循環(huán)放大大幅提高了檢測(cè)靈敏度,對(duì)OTA檢測(cè)靈敏度達(dá)到0.64 pg/mL。
絲網(wǎng)印刷技術(shù)(Screen-Printed Electrodes,SPE)是EC傳感器制備的前沿技術(shù)之一,使EC傳感器能夠更方便用于各種分析。然而,根據(jù)EC的特殊用途,選擇納米材料作為SPEs基材非常重要[40]。碳納米材料或改性碳納米材料,如石墨烯[41]、石墨[42]、富勒烯[43]和碳納米管(CNTs)[44],是SPE最常用的基材。這些納米材料對(duì)EC傳感器產(chǎn)生了巨大的影響[45],能夠提高生物分子的固定化效率和加速電極表面的電荷轉(zhuǎn)移速率。此外,可以增加EC中介以放大來自SPEs的信號(hào)和實(shí)現(xiàn)多目標(biāo)分析[46]。Chaiyo等[47]用Nafion/離子液體/石墨烯復(fù)合物作為基材,通過SPE技術(shù)制備EC傳感器,能夠同時(shí)檢測(cè)鋅、鎘、鉛等目標(biāo)物。
納米結(jié)構(gòu)的MOFs材料(nMOFs)在檢測(cè)各種目標(biāo)物的傳感領(lǐng)域中具有廣泛的應(yīng)用潛力,因而受到越來越多的關(guān)注[48]。此外,nMOFs有機(jī)配體上的特殊官能團(tuán)可通過π-π堆積、氫鍵和靜電力,與帶負(fù)電荷的核酸序列之間發(fā)生作用,從而更有利于構(gòu)建高性能傳感界面[49]。目前,已有研究人員通過nMOFs與適配體結(jié)合開發(fā)系列EC傳感器[50]。Liu等[51]提出了一種基于類似Zr-MOFs的可調(diào)諧EC用于蛋白質(zhì)檢測(cè),具有較高的靈敏度、良好的重復(fù)性和在實(shí)際樣品中的適用性。隨后,同一組人通過一鍋法制備了嵌入Au納米團(tuán)簇的2D Zr-MOFs納米片(2D AuNCs@521-MOF)[52],能夠?qū)煽ㄒ蜻M(jìn)行超敏檢測(cè)。
3.4 光譜傳感
光譜傳感中拉曼光譜的靈敏度最好,本文重點(diǎn)介紹表面增強(qiáng)拉曼光譜(Surface-enhanced Raman Spectroscopy,SERS)及其應(yīng)用。SERS是入射光激發(fā)納米尺度貴金屬材料產(chǎn)生的一種拉曼散射增強(qiáng)效應(yīng),可實(shí)現(xiàn)對(duì)單分子的高靈敏“指紋”識(shí)別。SERS技術(shù)具有良好的靈敏度、單分子檢測(cè)能力和豐富的光譜信息等優(yōu)點(diǎn),在目標(biāo)物快速傳感分析中成為一種很有前途的光譜技術(shù)[53],在食品安全[54]、環(huán)境監(jiān)測(cè)[55]和健康[56]等領(lǐng)域迅速發(fā)展。
SERS分析中,光譜信號(hào)增強(qiáng)是其中關(guān)鍵和核心[57]。納米材料在SERS信號(hào)增強(qiáng)方面的優(yōu)勢(shì)已得到驗(yàn)證,并獲得良好的分析結(jié)果。作為典型的AuNMs,AuNPs和金納米棒(AuNRs)具有可見光激發(fā)的局部表面等離子共振(Localized Surface Plasmon Resonance, LSPR)特性,可以集中局部電磁場(chǎng)[58],提高SERS檢測(cè)信號(hào)和檢測(cè)靈敏度。Cheng等[59]應(yīng)用二次氧化石墨烯與AuNPs結(jié)合,實(shí)現(xiàn)了油炸食品中丙烯酰胺的高敏檢測(cè),檢測(cè)靈敏度達(dá)到2.0 μg/kg。Alsammarraie 和Lin[60]應(yīng)用AuNRs陣列增強(qiáng)西維因農(nóng)藥殘留,實(shí)現(xiàn)對(duì)牛奶和水果中西維因殘留的檢測(cè),檢測(cè)靈敏度達(dá)50 μg/kg。多目標(biāo)同時(shí)傳感分析是SERS的特點(diǎn),Xie等[61]開發(fā)了AuNPs增強(qiáng)SERS信號(hào),快速檢測(cè)呋喃類抗生素(包括呋喃丹、呋喃他酮及其混合物)的方法。用平均粒徑為50 nm的AuNPs活性SERS基底研究了對(duì)硝基呋喃類抗生素信號(hào)增強(qiáng)效果,建立了硝基呋喃類化合物的SERS傳感分析方法。在最佳條件下,LOD可達(dá)到5.0 μg/kg。
近年來,一些基于MOFs修飾AuNMs的小分子SERS檢測(cè)方法得到了發(fā)展。MOFs材料的多孔性對(duì)目標(biāo)分析物能夠更好的富集,同時(shí)能夠保證納米材料的穩(wěn)定性。如He等[62]成功制備了核殼型Au@MOF-5納米結(jié)構(gòu),其中單個(gè)AuNP核被均勻的MOF-5殼包裹。與裸AuNPs和純MOF-5微球相比,殼厚為(3.2±0.5)nm的核殼Au@MOF-5納米結(jié)構(gòu)對(duì)CO2具有獨(dú)特的SERS活性(見圖4)。Hu等[63]將AuNP嵌入的MOFs(MIL-101)進(jìn)行高靈敏度的SERS檢測(cè)。新的SERS底物對(duì)多種不同的目標(biāo)分析物具有高度的敏感性、穩(wěn)定性和親和性,羅丹明6 G和苯扎定的LOD分別為41.75 fmol和0.54 fmol。由于MOFs具有保護(hù)殼,該底物還表現(xiàn)出高穩(wěn)定性和重復(fù)性,以及分子篩效應(yīng)。
4 存在的問題與展望
目前,納米傳感在農(nóng)產(chǎn)品質(zhì)量安全監(jiān)測(cè)領(lǐng)域廣泛應(yīng)用并具有良好的前景。納米材料是納米傳感的基礎(chǔ),也是實(shí)現(xiàn)納米傳感的靈敏度、穩(wěn)定性和可靠性等分析性能的關(guān)鍵。盡管納米傳感發(fā)展迅速,但仍有一些瓶頸問題需要解決。
首先,納米材料的制備和修飾技術(shù)需要進(jìn)一步提升,以獲得性能更優(yōu)和更加穩(wěn)定的功能性納米材料。如貴金屬納米材料形貌與其LSPR性質(zhì)有密切的關(guān)聯(lián)性,如何精確控制納米材料形貌,獲得具有理想LSPR性能的貴金屬納米材料,需要進(jìn)一步解決。近年來,MOFs材料的特殊性質(zhì)和優(yōu)異性能越來越受關(guān)注,但MOFs材料的穩(wěn)定性和可控多級(jí)孔的獲得仍是困擾其應(yīng)用的難題。
其次,多目標(biāo)、高通量納米傳感器件在實(shí)際應(yīng)用中的價(jià)值廣受關(guān)注。盡管科研人員已經(jīng)開發(fā)出系列高通量納米傳感分析技術(shù)和器件,但在保證分析性能的前提下,不同種類化合物同時(shí)進(jìn)行傳感分析,更高的分析通量,仍然是一個(gè)瓶頸。需要在納米傳感器件的構(gòu)筑方面努力。
最后,在線傳感分析在農(nóng)產(chǎn)品質(zhì)量安全智慧監(jiān)控方面有迫切需求,特別是農(nóng)產(chǎn)品生產(chǎn)鏈條長(zhǎng),具有“鮮活性”的特性,需要快速、實(shí)時(shí)、在線監(jiān)測(cè)。但受納米傳感器件的再生性限制,難以實(shí)現(xiàn)在線傳感分析。因此,需要在納米材料和納米技術(shù)以及納米傳感器件構(gòu)筑方面獲得突破。
通過解決上述納米材料精控制備和納米傳感器件構(gòu)筑中的瓶頸問題,納米傳感在農(nóng)產(chǎn)品質(zhì)量安全中的應(yīng)用會(huì)得到迅速發(fā)展。更重要的是利用納米材料和納米技術(shù)制作傳感器,是立足于原子尺度操控,從而極大地豐富了傳感理論,提升了傳感器的制作水平,拓寬了傳感器的應(yīng)用領(lǐng)域。未來,隨著納米材料制備技術(shù)的成熟,農(nóng)產(chǎn)品質(zhì)量安全納米傳感器的尺寸更小、檢測(cè)精度更高,納米傳感器的構(gòu)筑向集成化、智能化方向發(fā)展,傳感性能向?qū)捔砍?、高精度、?qiáng)抗干擾、長(zhǎng)壽命和可重復(fù)利用的方向發(fā)展。
參考文獻(xiàn):
[1] FRACETO L F, GRILLO R, DE MEDEIROS G A, et al. Nanotechnology in agriculture: Which innovation potential does it have?[J]. Front. Environ. Sci., 2016, 4: ID 20.
[2] WANG P, LIN Z, SU X, et al. Application of Au based nanomaterials in analytical science[J]. Nano Today, 2017, 12: 64-97.
[3] KWAK S Y, WONG M H, LEW T T S, et al. Nanosensor technology applied to living plant systems[J]. Annual Review of Analytical Chemistry, 2017, 10(1): 113-140.
[4] MUKHERJEE A, MAJUMDAR S, SERVIN A D, et al. Carbon nanomaterials in agriculture: A critical review[J]. Frontiers in Plant Science, 2016, 7: ID 172.
[5] WANG Z, YU J, GUI R, et al. Carbon nanomaterials-based electrochemical aptasensors[J]. Biosens. Bioelectron, 2016, 79: 136-149.
[6] PAN M, YIN Z, LIU K, et al. Carbon-based nanomaterials in sensors for food safety[J]. Nanomaterials, 2019, 9(9): ID 1330.
[7] CHENG H, YANG N, LU Q, et al. Syntheses and properties of metal nanomaterials with novel crystal phases[J]. Advanced Materials, 2018, 30(26): ID 1707189.
[8] WANG P, XIE L, JOSEPH E A, et al. Metal-organic frameworks for food safety[J]. Chem. Rev., 2019, 119(18): 10638-10690.
[9] KIM S J, CHOI S J, JANG J S, et al. Innovative nanosensor for disease diagnosis[J]. Acc. Chem. Res., 2017, 50(7): 1587-1596.
[10] LIAO X, LIAO Q, ZHANG Z, et al. A highly stretchable ZnO@Fiber-based multifunctional nanosensor for strain/temperature/UV detection[J]. Advanced Functional Materials, 2016, 26(18): 3074-3081.
[11] FENG Q, ZENG Y, XU P, et al. Tuning the electrical conductivity of amorphous carbon/reduced graphene oxide wrapped-Co3O4 ternary nanofibers for highly sensitive chemical sensors[J]. J. Mater. Chem. A, 2019, 7(48): 27522-27534.
[12] HUY B T, SEO M H, ZHANG X, et al. Selective optosensing of clenbuterol and melamine using molecularly imprinted polymer-capped CdTe quantum dots[J]. Biosens. Bioelectron, 2014, 57: 310-316.
[13] TANG Y, GAO Z, WANG S, et al. Upconversion particles coated with molecularly imprinted polymers as fluorescence probe for detection of clenbuterol[J]. Biosens. Bioelectron, 2015, 71: 44-50.
[14] MEHRZAD-SAMARIN M, FARIDBOD F, DEZFULI A S, et al. A novel metronidazole fluorescent nanosensor based on graphene quantum dots embedded silica molecularly imprinted polymer[J]. Biosens. Bioelectron, 2017, 92: 618-623.
[15] WANG B, WANG P, XIE L, et al. A stable zirconium based metal-organic framework for specific recognition of representative polychlorinated dibenzo-p-dioxin molecules[J]. Nat. Commun., 2019, 10: ID 3861.
[16] YANG H, WANG B, CHENG J, et al. Determination and removal of clenbuterol with a stable fluorescent zirconium(IV)-based metal organic framework[J]. Microchimi Acta, 2019, 186: ID 454.
[17] LYU J, WANG B, XIE Y, et al. Selective detection of two representative organic arsenic compounds in aqueous medium with metal-organic frameworks[J]. Environ. Sci.: Nano, 2019, 6: 2759-2766.
[18] QIU C, GONG Y, GUO Y, et al. Sensitive fluorescence detection of phthalates by suppressing the intramolecular motion of nitrophenyl groups in porous crystalline ribbons [J]. Anal. Chem., 2019, 91(21): 13355-13359.
[19] SEPULVEDA B, ANGELOME P C, LECHUGA L M, et al. LSPR-based nanobiosensors[J]. Nano Today, 2009, 4(3): 244-251.
[20] NIIKURA K, NAGAKAWA K, OHTAKE N, et al. Gold nanoparticle arrangement on viral particles through carbohydrate recognition: A non-cross-linking approach to optical virus detection[J]. Bioconjug. Chem., 2009, 20(10): 1848-1852.
[21] CHO M, HAN M S, BAN C. Detection of mismatched DNAs via the binding affinity of MutS using a gold nanoparticle-based competitive colorimetric method[J]. Chem. Commun., 2008, 14(38): 4573-4575.
[22] LI W, FENG L, REN J, et al. Visual detection of glucose using conformational switch of i-motif DNA and non-crosslinking gold nanoparticles[J]. Chem. Eur. J, 2012, 18(40): 12637-12642.
[23] WANG H, WANG Y X, JIN J Y, et al. Gold nanoparticle-based colorimetric and “turn-on” fluorescent probe for mercury (II) ions in aqueous solution [J]. Anal. Chem., 2008, 80(23): 9021-9028.
[24] MEDLEY C D, SMITH J E, TANG Z, et al. Gold nanoparticle-based colorimetric assay for the direct detection of cancerous cells[J]. Anal. Chem., 2008, 80(4): 1067-1072.
[25] ZHOU Y, WANG P, SU X, et al. Colorimetric detection of ractopamine and salbutamol using gold nanoparticles functionalized with melamine as a probe[J]. Talanta, 2013, 112: 20-25.
[26] DZANTIEV B B, BYZOVA N A, URUSOV A E, et al. Immunochromatographic methods in food analysis[J]. TrAC Trends in Analytical Chemistry, 2014, 55: 81-93.
[27] WU S, ZHU F, HU L, et al. Development of a competitive immunochromatographic assay for the sensitive detection of amantadine in chicken muscle[J]. Food Chem., 2017, 232: 770-776.
[28] SONG S, SURYOPRABOWO S, LIU L, et al. Development of monoclonal antibody-based colloidal gold immunochromatographic assay for analysis of halofuginone in milk[J]. Food Agr. Immunol., 2019, 30(1): 112-122.
[29] REN M, XU H, HUANG X, et al. Immunochromatographic assay for ultrasensitive detection of aflatoxin B1 in maize by highly luminescent quantum dot beads[J]. ACS Appl. Mater. Interfaces, 2014, 6(16): 14215-14222.
[30] WANG P, WANG Z, SU X. A sensitive and quantitative fluorescent multi-component immuno-chromatographic sensor for β-agonist residues[J]. Biosens. Bioelectron, 2015, 64: 511-516.
[31] WANG R, ZHANG W, WANG P, et al. A paper-based competitive lateral flow immunoassay for multi β-agonist residues by using a single monoclonal antibody labelled with red fluorescent nanoparticles[J]. Microchimi. Acta, 2018, 185(3): ID 191.
[32] WANG P, WANG R, ZHANG W, et al. Novel fabrication of immuno-chromatographic assay based on up conversion phosphors for sensitive detection of clenbuterol[J]. Biosens. Bioelectron, 2016, 77: 866-870.
[33] MA Y, MAO Y, HUANG D, et al. Portable visual quantitative detection of aflatoxin B1 using a target-responsive hydrogel and distance-readout microfluidic chip[J]. Lab. Chip., 2016, 16(6): 3097-3104.
[34] HU S, OUYANG W, GUO L, et al. Facile synthesis of Fe3O4/g-C3N4/HKUST-1 composites as a novel biosensor platform for ochratoxin A[J]. Biosens. Bioelectron, 2017, 92: 718-723.
[35] ZHANG W, WANG R, LUO F, et al. Miniaturized electrochemical sensors and their point-of-care applications[J]. Chinese Chem. Lett., 2020, 31(3): 589-600.
[36] RIVAS L, MAYORGA-MARTINEZ C C, QUESADA-GONZáLEZ D. Label-free impedimetric aptasensor for ochratoxin-A detection using iridium oxide nanoparticles[J]. Anal. Chem., 2015, 87(10): 5167-5172.
[37] YANG F, WANG P, WANG R, et al. Label free electrochemical aptasensor for ultrasensitive detection of ractopamine[J]. Biosens. Bioelectron, 2016, 77: 347-352.
[38] ZHOU Y, WANG P, SU X, et al. Sensitive immunoassay for the β-agonist ractopamine based on glassy carbon electrode modified with gold nanoparticles and multi-walled carbon nanotubes in a film of poly-arginine[J]. Microchim Acta, 2014, 181: 1973-1979.
[39] YANG M, JIANG B, XIE J, et al. Electrochemiluminescence recovery-based aptasensor for sensitive Ochratoxin A detection via exonuclease-catalyzed target recycling amplification[J]. Talanta, 2014, 125: 45-50.
[40] COUTO R A S, LIMA J L F C, QUINAZ M B, et al. Recent developments, characteristics and potential applications of screen-printed electrodes in pharmaceutical and biological analysis[J]. Talanta, 2016, 146: 801-814.
[41] ZANG D, YAN M, GE S, et al. A disposable simultaneous electrochemical sensor array based on a molecularly imprinted film at a NH2-graphene modified screen-printed electrode for determination of psychotropic drugs[J]. Analyst, 2013, 138(9): 2704-2711.
[42] FERNáNDEZ E, VIDAL L, INIESTA J, et al. Screen-printed electrode-based electrochemical detector coupled with in-situ ionic-liquid-assisted dispersive liquid-liquid microextraction for determination of 2,4,6-trinitrotoluene[J]. Anal. Bioanal. Chem., 2014, 406(8): 2197-2204.
[43] CHEN A, CHATTERJEE S. Nanomaterials based electrochemical sensors for biomedical applications[J]. Chem. Soc. Rev., 2013, 42(12): 5425-5438.
[44] PHAM X H, NGOCBUI M P, AILI C, et al. Electrochemical characterization of a single-walled carbon nanotube electrode for detection of glucose[J]. Anal. Chim. Acta, 2010, 671(1-2): 36-40.
[45] SYEDMORADI L, DANESHPOUR M, ALVANDIPOUR M, et al. Point of care testing: The impact of nanotechnology[J]. Biosens. Bioelectron., 2017, 87: 373-387.
[46] AHMED M U, HOSSAIN M M, SAFAVIEH M, et al. Toward the development of smart and low cost point-of-care biosensors based on screen printed electrodes[J]. Crit. Rev. Biotechnol., 2016, 36(3): 495-505.
[47] CHAIYO S, MEHMETI E, ?AGAR K, et al. Electrochemical sensors for the simultaneous determination of zinc, cadmium and lead using a Nafion/ionic liquid/graphene composite modified screen-printed carbon electrode[J]. Anal. Chim. Acta, 2016, 918: 26-34.
[48] LI Y, ZHANG S, SONG D. A luminescent metal-organic framework as a turn-on sensor for DMF vapor[J]. Angew. Chem. Int. Ed., 2013, 52(2): 710-713.
[49] RAMASWAMY P, WONG N E, SHIMIZU G K H. MOFs as proton conductors-challenges and opportunities[J]. Chem. Soc. Rev., 2014, 43(16): 5913-5932.
[50] GUO H, ZHENG Z, ZHANG Y, et al. Highly selective detection of Pb2+ by a nanoscale Ni-based metal-organic framework fabricated through one-pot hydrothermal reaction[J]. Sens. Actuators B-Chem., 2017, 242: 1201-1209.
[51] LIU C, ZHANG Z, CHEN M, et al. Pore modulation of zirconium-organic frameworks for high-efficiency detection of trace proteins[J]. Chem. Commun., 2017, 53(28): 3941-3944.
[52] SU F, ZHANG S, JI H, et al. Two-dimensional zirconium-based metal-organic framework nanosheet composites embedded with Au nanoclusters: A highly sensitive electrochemical aptasensor toward detecting cocaine [J]. ACS Sens., 2017, 2(7): 998-1005.
[53] NIE S, EMORY S R. Probing single molecules and single nanoparticles by surface-enhanced Raman scattering [J]. Science, 1997, 275(5303): 1102-1106.
[54] CHENG J, FAN M, WANG P, et al. The twice-oxidized graphene oxide/gold nanoparticles composite SERS substrate for sensitive detection of clenbuterol residues in animal-origin food samples[J]. Food Anal. Methods, 2020, 13(4): 902-910.
[55] 程劼, 王培龍, 蘇曉鷗. 表面增強(qiáng)拉曼光譜檢測(cè)二噁英類化合物研究進(jìn)展[J]. 化學(xué)學(xué)報(bào), 2019, 77: 977-983.
CHENG J, WANG P, SU X. Recent progress on the detection of dioxins based on surface-enhanced Raman spectroscopy[J]. Acta Chimica Sinica, 2019, 77: 977-983.
[56] PORTER M D, LIPERT R J, SIPERKO L M, et al. SERS as a bioassay platform: Fundamentals, design, and applications[J]. Chem. Soc. Rev., 2008, 37(5): 1001-1011.
[57] BERNAT A, SAMIWALA M, ALBO J, et al. Challenges in SERS-based pesticide detection and plausible solutions[J]. J. Agric. Food Chem., 2019, 67(45): 12341-12347.
[58] LI L, STEINER U, MAHAJAN S. Single nanoparticle SERS probes of ion intercalation in metal-oxide electrodes[J]. Nano Lett., 2014, 14(2): 495-498.
[59] CHENG J, ZHANG S, WANG S, et al. Rapid and sensitive detection of acrylamide in fried food using dispersive solid-phase extraction combined with surface-enhanced Raman spectroscopy[J]. Food Chemistry, 2019, 276: 157-163.
[60] ALSAMMARRAIE F K, LIN M. Using standing gold nanorod arrays as surface-enhanced Raman spectroscopy (SERS) substrates for detection of carbaryl residues in fruit juice and milk[J]. J. Agric. Food Chem., 2017, 65(3): 666-674.
[61] XIE Y, ZHU X, SUN Y, et al. Rapid detection method for nitrofuran antibiotic residues by surface-enhanced Raman Spectroscopy[J]. Eur. Food Res. Technol., 2012, 235(3): 555-561.
[62] HE L, LIU Y, LIU J, et al. Core-Shell Noble-Metal@ Metal-Organic-Framework nanoparticles with highly selective sensing property[J]. Angew. Chem. Int. Ed., 2013, 52(13): 3741-3745.
[63] HU Y, LIAO J, WANG D, et al. Fabrication of gold nanoparticle-embedded metal-organic framework for highly sensitive surface-enhanced Raman scattering detection[J]. Anal. Chem., 2014, 86(8): 3955-3963.
Abstract: Nano materials with special size effect and excellent photoelectric properties have been highly valued and widely used in sensing analysis for greatly improving the performance of sensor analysis technology. In recent years, with the rapid development of smart agriculture, the quality and safety of agricultural products as an important part of agricultural production have attracted more and more attentions. There are many harmful ingredients, including pesticides, veterinary drugs, mycotoxins, and environmental contaminants etc, can potentially affected the quality and safety of agricultural products. Therefore, high performance analytical methods and sensing technologies are essential. Thanks to the emerging of nano materials, they provide a novel approach to improve the analytical performances of the sensing technologies. Furthermore, the sensors based on nano materials have also been utilized into monitoring the harmful substances in agricultural products. This review briefly described the properties and characteristics of several commonly used nano materials, including carbon nano materials, noble metal based nano materials and metal-organic framework materials, follow discussed on the common sensing and analysis technologies and devices based on nano materials, such as chemical sensor, biosensor, electrochemical sensor and spectral sensor, as well as the application of nano sensing technology in the quality and safety monitoring of agricultural products. Especially, the function of nano materials in sensors and analytical performances of the developed sensors had been discussed in detailed. Chemical sensor devices had the characteristics of fast response speed and high sensitivity. They were widely used in environmental monitoring, food safety and medical diagnosis, such as monitoring hazardous substances, clenbuterol and melamine, metronidazole, dioxins, etc. Biosensors were widely used to monitor prohibited additives, mycotoxins, and so on. Electrochemical sensors were typically equipped with miniaturized analysis equipment, which detected trace targets, including small organic molecules, metal ions and biomolecules, by measuring changed in current and other electrochemical signals. This article introduced surface-enhanced Raman spectroscopy (SERS) , which was one of spectral sensor, and its applications. SERS technology had the advantages of good sensitivity, single molecule detection capability and rich spectral information. It had become a promising spectral technology in the rapid sensing analysis of target objects, and is developing rapidly in the fields of food safety, environmental monitoring and health. Finally, the existing problems of nano sensing and analysis technology, such as achievement of high-performance nano materials, fabrication of sensing devices and construction of high flux sensing arrays were summarized. The development trend and prospect of nanosensor were also discussed. It is believed that the review could provide a lot of useful information for the readers to understand the development of sensing technology for the quality and safety of agricultural products.
Key words: nanomaterials; smart agriculture; quality and safety for agro-products; nano sensor