Ikhemistri yombane ye-methylene blue: iielektrodi, iiprobhoni zeredox, nezivamvo

Umfundi wesidanga esiphezulu wenza ivoltammogram ejikelezayo ye-methylene blue kwi-elektrodi yekhabhoni eyiglasi, abone iziqongo ezibini ezicacileyo, aze agqibe kwelokuba isivamvo sigqityiwe. Kwiveki elandelayo iziqongo zitshintshile kwindawo, zinciphile, okanye zahlukene, yaye akukho nto kwinkqubo echaza isizathu. Idayi ayitshintshanga. Ingcamango ebisekelwe kuyo imilinganiselo ibingaphelelanga.

I-methylene blue ifanelwe yindawo yayo kwikhemistri yombane ngenxa yezizathu ezithathu. Itshintshiselana ngee-elektroni ngendlela ebuyela umva kwiipotenshiyali ezingagqithisanga, ibambelela kumphezulu ize yenze iipolima zibe ziifilimu, yaye ibophelela kwiiasidi zenukleyiki. Nganye kwezi yingcamango eyahlukileyo, yaye nganye isilela ngendlela yayo. Olu hlaziyo luyazahlula: isibini seredox, ukufundwa komqondiso, i-elektrodi elungisiweyo, indima yokuba ngumlamli, nolwakhiwo lwezivamvo olwakhelwe phezu kwazo.

Isibini esinye, iimo ezimbini, iprotoni enye

Impendulo esisiseko kwi-pH engathathi cala idla ngokubhalwa njengekhathiyoni enye efakwe ioksideshini, ethatha ii-elektroni ezimbini neprotoni enye ukuze inike imo yeleuco engenambala, efumene ii-elektroni:

MB+ + H+ + 2e- gives LMB

Ipotenshiyali yeredox ye-methylene blue kwi-pH 7 ikufuphi ne-+11 mV xa ithelekiswa ne-elektrodi yehayidrojeni esemgangathweni, njengoko kuxeliwe kuphononongo lwakutshanje lwendlela le dayi esebenza ngayo kwi-Chemistry Europe. Ngenxa yokuba iprotoni enye ihamba nee-elektroni ezimbini, ipotenshiyali esesikweni itshintshela kwicala elinegative malunga ne-30 mV ngalo lonke ukwanda kweyunithi enye ye-pH. Olo thambeka luphawu lokuqala lokuxilonga olufanele ukukhunjulwa. Ukuba isiqongo sakho sihamba malunga ne-30 mV ngeyunithi nganye ye-pH, ubona isibini esilindelekileyo. Ukuba sihamba nge-60 mV ngeyunithi nganye, inani leeprotoni litshintshile. Ukuba phantse asishukumi, umqondiso usenokuba uvela kwifilimu yomphezulu enekhemistri yayo yeeasidi neziseko, kungekhona kwidayi enyibilikileyo.

Ukuchaza iielektrodi zesalathiso ngumkhwa wesibini. Iipotenshiyali ezichazwe xa zithelekiswa ne-Ag/AgCl, i-SCE, ne-NHE zahluka ngamashumi ukuya kumakhulu eemillivolts, yaye isisombululo sokuzalisa sitshintsha amanani nangakumbi. Yonke ipotenshiyali kweli nqaku ichaza isalathiso sayo. Naliphi na iphepha elingakwenziyo oko alinakusetyenziswa kwakhona. Umahluko wolwakhiwo phakathi kwezi mo zimbini, ikhathiyoni ethe tyaba xa ithelekiswa nemolekyuli engathathi cala nebhetyebhetye, nawo uyinxalenye yalo mba, yaye iphepha elihamba neli elithetha ngesibini seredox liwuxoxa ngokweenkcukacha.

Into eboniswa yivoltammogram ye-methylene blue ngokwenene

Kwi-elektrodi yekhabhoni eyiglasi ecocekileyo, engagqunywanga, ekwisisombululo sephosphate esigcina i-pH iphantse ingathathi cala, i-methylene blue enyibilikileyo idla ngokunika isiqongo se-anode esikufuphi ne-0.15 ukuya kwi-0.18 V kwicala elinegative xa sithelekiswa ne-Ag/AgCl, kunye nesiqongo secathode esikufuphi ne-0.20 ukuya kwi-0.25 V kwicala elinegative xa sithelekiswa nesalathiso esifanayo. Iindawo ezichanekileyo zitshintsha ngokwesantya sokuskena, imbali yomphezulu, nesisombululo sokuzalisa isalathiso, yaye umlinganiselo wakutshanje ofumaneka simahla kwikhabhoni eyiglasi engagqunywanga ubeka isiqongo secathode kufuphi ne-0.18 V kwicala elinegative kwi-pH 7.4 phantsi kweemeko zawo.

Esi sibini sichazwa kakuhle njengesiphantse sibuyela umva. Isibini esifanelekileyo see-elektroni ezimbini esibuyela umva besiya kubonisa iziqongo ezahlulwe malunga ne-30 mV. Amaza e-methylene blue adla ngokuba banzi ngakumbi yaye angalingani, yaye ukunamathela kumphezulu kuyawenza nzima umfanekiso. Obo bunzima luphawu lokuxilonga, hayi ingxolo. Umsinga wesiqongo okhula ngokuhambelana ngqo nesantya sokuskena walatha kwidayi enamathele kumphezulu. Umsinga wesiqongo okhula ngokwengcambu yesikwere yesantya sokuskena walatha kwidayi efika isuka kwisisombululo ngokusasazeka. Iigrafu ezininzi zokwenene zidibanisa zombini, nto leyo ebangela ukuba isisombululo esifanayo sinike ukuphakama kweziqongo okwahlukileyo kwi-elektrodi esandul’ ukupolishwa nakwisetyenzisiweyo.

Ioksijini enyibilikileyo yongeza umsinga wayo wokufumana ii-elektroni kuluhlu olufanayo lwepotenshiyali, ngoko umsebenzi wokumisela ubungakanani udla ngokwenziwa emva kokususwa kweoksijini okanye xa impembelelo yayo ithathelwe ingqalelo. Yaye i-methylene blue ingcolisa umphezulu: idayi enamatheleyo itshintsha umphezulu kumjikelo ngamnye, ngoko ukushenxa kweziqongo ngexesha lokuskena okuphindaphindiweyo bubungqina malunga ne-elektrodi, kungekhona ngento ehlalutywayo.

Ukusuka kwidayi enyibilikileyo ukuya kwi-elektrodi elungisiweyo

Isivamvo sebhayoloji esine-elektrodi elungiswe nge-methylene blue siqala ngokuqaphela into elula. Idayi inamathela ngamandla kwikhabhoni, ngoko ukuntywilisela nje i-elektrodi kwisisombululo sedayi sele kuyilungisa. Ukunamathelisa okulula kukwalulwakhiwo olungazinzanga kakhulu, kuba idayi iphinda iphume iye kwisisombululo. Yonke enye into kweli candelo yindlela yokujongana noko kuphuma kwedayi.

Eyona mpendulo imiselwe kakuhle yi-poly(methylene blue) eyenziwe ibe yipolima ngombane. Ukujikelezisa i-elektrodi ngendlela yeoksideshini kwisisombululo sedayi kubeka ifilimu esebenzayo kwiredox, ehlala endaweni yayo ngcono kakhulu kunemonomer enamathele kumphezulu. Inkqubo esemgangathweni yohlobo lwe-Karyakin isebenzisa malunga ne-1 mM yedayi kwisisombululo seborate esigcina i-pH, esiyi-0.02 M kufuphi ne-pH 9.1, kunye ne-0.1 M yepotassium chloride, ijikelezisa ukusuka malunga ne-0.40 V kwicala elinegative ukuya kwi-1.20 V kwicala elinepositive kangangemijikelo emalunga ne-30, njengoko kubhalwe kwingxelo yethisisi yase-Durham yale ndlela. Isithinteli se-pH esinealkali sibalulekile: ukukhula kwefilimu kuqhubeka ngeemo ezifakwe ioksideshini eziveliswa kwiipotenshiyali ezinepositive, yaye uluhlu lwepotenshiyali kufuneka lufikelele kuzo.

Olunye ulwakhiwo lusombulula iingxaki ezahlukileyo. Intlama yekhabhoni neelektrodi eziprintwe ngesikrini zincama ukuchaneka ukuze zibe nokulahlwa emva kokusetyenziswa. Izinto ezidityanisiweyo ezineenanotubes okanye igraphene zandisa indawo esebenzayo zize zenze iziqongo zicace ngakumbi. Iielektrodi zegolide ezineeprobhoni ezibotshelelwe ngethiol zisetyenziswa kwizivamvo zeeasidi zenukleyiki ezichazwe ngezantsi. Ukuvalelwa phantsi kweefilimu ze-Nafion kunciphisa ukuphuma kwedayi, kodwa kwenza impendulo icothe. Umbuzo woyilo usoloko ufana: yeyiphi indlela yokusilela oyithintelayo, yaye uncame ntoni ukuze uyithintele?

Ingcamango yomlamli: ngumgqithisi, hayi ireyijenti

Xa isebenza njengomlamli weredox kwivoltammetry ejikelezayo, i-methylene blue enyibilikileyo idlulisa ii-elektroni phakathi kwento ehlalutywayo engatshintshiselani lula ngee-elektroni kunye ne-elektrodi. Idayi efakwe ioksideshini yamkela ii-elektroni kwikhemistri yesampuli, i-elektrodi iphinda ifake ioksideshini kwidayi efumene ii-elektroni, yaye umsinga olinganisiweyo ubonisa ukuphindaphinda kwale nkqubo. Uxinzelelo oluqhelekileyo lwedayi esasazeka ngokukhululekileyo lungamashumi e-micromolar, malunga ne-10 ukuya kwi-60, kunokuba lube ngumgangatho othile osisigxina.

Iintlobo ezintathu zekhemistri esebenzisa umlamli zivela rhoqo. Idayi ilamla ioksideshini ye-NADH, kuquka inkqubo edityaniswe nee-enzyme, yaye iifilimu ze-poly(methylene blue) zikhawulezisa kwaloo mpendulo kumphezulu ngombane. Xa ikunye nee-oxidase, inokusebenza njengesamkeli see-elektroni esenziwe ngumntu. Kwiinkqubo zeperoxidase, idayi efumene ii-elektroni izigqithisela kwizinto eziphakathi zempendulo ezinciphisa iperoxide, nto leyo evumela ukufunyanwa kwehydrogen peroxide kwiipotenshiyali ezisezantsi ezisetyenzisiweyo, apho ukuphazamiseka kuncinane khona. Uphononongo lwe-Chemical Science luka-2025 lweoksideshini ye-NADH elamlwayo luchaza indlela oku kwenzeka ngayo ngokweenkcukacha. Xa ubungakanani bedayi buphezulu, umqondiso osisiseko womlamli nekhemistri yeoksijini zinokuwudlula umqondiso wohlalutyo, ngoko uxinzelelo lomlamli yinto ekufuneka ilungiselelwe eyona meko ilungileyo, hayi ukugqithiswa kwereyijenti.

Izivamvo zeeasidi zenukleyiki: apho ukubophelela kuba ngumsinga

I-methylene blue ibophelela kwi-DNA ngomxube wokungena phakathi kweziseko, umtsalane we-electrostatic, kunye nokunxibelelana okukhethekileyo neguanine, ngoko ukuyibiza nje ngokuba yinto engena phakathi kweziseko kuyenza ibonakale ilula kakhulu le khemistri. Uyilo lwezivamvo luguqula oko kubophelela kube ngumsinga kulwakhiwo olwahlukileyo kabini, yaye ukuzibhidanisa yeyona mpazamo ixhaphakileyo ekufundweni kolu ncwadi.

Kuyilo olungenaleyibhile, idayi ekhululekileyo kwisisombululo inxulumana ne-DNA yeprobhoni ebotshelelwe kumphezulu, yaye ukudityaniswa kwemicu ehambelanayo kutshintsha umqondiso. Kuhlobo oluqhelekileyo apho umqondiso ucimayo: iprobhoni enomcu omnye iqokelela idayi ize inike isiqongo esikhulu, ngoxa ukudityaniswa kwayo ibe yi-DNA enemicu emibini kutshintsha imeko ejikeleze idayi kuze kwehlise umqondiso. Ezi ndlela zidla ngokufikelela kwimida yokufumanisa ekwinqanaba le-nanomolar. Omnye umzekelo wabeka i-DNA ehambelanayo kwiinanotubes zekhabhoni ezinodonga olunye eziphezu kwegolide, waza waxela ubudlelwane obuthe ngqo ukusuka kwi-100 ukuya kwi-1000 nM, nomda wokufumanisa okufuphi ne-7 nM kwi-Electroanalysis.

Kuyilo oluneleyibhile, idayi ibotshelelwe ngesibophelelo sekhovalenti kwelinye icala leprobhoni, elinye icala libotshelelwe kwigolide ngeqela lethiol, yaye ivoltammetry yamaza asisikwere ilandelela isalathisi esibotshelelweyo. Izivamvo ze-aptamer zekhemistri yombane ezisekelwe ekusongweni zandisa le ngcamango: ukubophelela kwento ekujoliswe kuyo kulungisa ngokutsha i-aptamer kuze kushukumise isalathisi xa sithelekiswa ne-elektrodi. Isivamvo se-ochratoxin A esisebenzisa i-aptamer eneeleyibhile ezimbini, ithiol nedayi, kwigolide saxela uluhlu lwe-0.1 ukuya kwi-1000 pg per mL, nomda wokufumanisa okufuphi ne-0.095 pg per mL, sapapashwa kwi-Analytica Chimica Acta.

Lo mahluko ubalulekile xa kusonjululwa iingxaki. Kwiindlela ezingenaleyibhile idayi yinxalenye yesisombululo enoxinzelelo lwayo nokuxhomekeka kwayo kwi-pH. Kwiindlela ezineleyibhile idayi iyinxalenye yeprobhoni, yaye utshintsho lomqondiso lubonisa umgama neentshukumo, kungekhona ukuthathwa kwedayi.

Imizekelo yee-enzyme nezinto ezidityanisiweyo

Iifilimu ze-poly(methylene blue) zikwabambelela izivamvo ezisebenzisa ii-enzyme. Esinye isivamvo se-ammonium sadibanisa i-elektrodi eprintwe ngesikrini, iinanoparticles zegolide, nefilimu yedayi, saza sagquma ngaphezulu ngekhemistri ye-glutamate dehydrogenase. Ifilimu ifaka ioksideshini kwi-NADH ngoxa i-enzyme iyisebenzisa ngokuhambelana nobungakanani be-ammonium: i-0 ukuya kwi-300 micromolar, nomda wokufumanisa okufuphi ne-0.65 micromolar, njengoko kuxeliwe kwi-Biosensors. Lo mmandla uphela ugutyungelwe kuhlaziyo luka-2025 lwale dayi ekuvavanyeni ngezivamvo zekhemistri yombane kwi-Analytica Chimica Acta.

Iimeko ekufuneka zihambe nesiphumo ngasinye

Isalathiso esihamba neli nqaku malunga neendlela zovavanyo lokumisela ubungakanani sigubungela ngokubanzi indlela engqongqo yokukhalibhreyitha. Kwiziphumo zekhemistri yombane ngokukodwa, ezi nkcukacha kufuneka zibe kuyo yonke ingxelo yelebhu:

Isalathisi asilonyango

Umahluko wokugqibela ngulo eli phepha likhona ukuze liwugxininise. Ukuhla kwesiqongo samaza asisikwere xa imicu ehambelanayo idityaniswa kungqina ukuba ileyibhile yeredox ishukumile okanye ukuba ukubophelela kwedayi kutshintshile. Akungqini nto malunga nento eyenziwa yi-methylene blue emzimbeni wesigulana. Ikhemistri yomlinganiselo nomsebenzi webhayoloji zabelana ngemolekyuli, kodwa akukho nto yimbi: uxinzelelo olwahlukileyo, imixube yesampuli eyahlukileyo, yaye kwiibhayoloji iinwebu nee-enzyme zithatha indawo yeelektrodi ezichaseneyo. Gcina imibuzo yonyango kumaphepha omsebenzi webhayoloji, uze ugcine amabango ngezivamvo enxulumene ne-elektrodi, isithinteli se-pH, nendlela evelise iziphumo. Ileyibhile yeredox sisalathisi. Izalathisi zichaza uvavanyo, hayi umzimba.