I-methylene blue ne-leucomethylene blue: ipheya eyodwa ye-redox, imibala emibili

Umfundi ufaka amaconsi ambalwa kadayi oluhlaza okwesibhakabhaka eflaskini, alizulise, abuke umbala unyamalala. Uyalinyakazisa iflaski bese umbala oluhlaza okwesibhakabhaka ubuya. Akukho okufakiwe noma okukhishiwe phakathi kwalezi zimo ezimbili ngaphandle kwama-electron nokuthintana nomoya. Lelo flaski liqukethe lonke udaba lwalesi sihloko: i-methylene blue nohlobo lwayo oluncishisiwe, i-leucomethylene blue, okuguqukana kube ipheya ye-redox ebuyiseleka emuva, lapho umbala ubonisa khona umphumela.

Iphuzu elisebenzayo liza kuqala. Ukushintsha kombala akuwona umphumela oseceleni lapha. Kuwuphawu olusetshenziswa ekuhlaziyeni. Noma ubani owenza izingxube nge-methylene blue, oyisebenzisa ekuthayithretheni, noma ofundisa ngayo kufanele akwazi ukubhala ukusabela okuyingxenye ngekhanda, asho izimo ezikuphushela kwesobunxele noma kwesokudla, futhi asho ukungcola okufiphaza umphumela.

Ipheya ngesibalo esisodwa

I-methylene blue esesimweni se-oxidation iyi-cation ye-methylthioninium: uhlelo oluyisicaba lwe-phenothiazinium olunesulfure ne-nitrogen eringini emaphakathi neqembu le-dimethylamino ekugcineni ngakunye, olunikezwa njengosawoti we-chloride. I-PubChem iyibhalisa njenge-methylthioninium chloride, C.I. Basic Blue 9. Emanzini, i-monomer imunca ukukhanya eduze kuka-664 nm, okuyikho okudala umbala oluhlaza okwesibhakabhaka obonwa iso.

I-leucomethylene blue (LMB) encishisiwe inohlaka olufanayo, kodwa i-nitrogen yeringi emaphakathi ithole i-proton futhi i-chromophore iphazamisekile. Ayinayo ishaji eduze kwe-pH engathathi hlangothi futhi icishe ingabi nambala, imunca ukukhanya okubonakalayo ngezinga elincane kakhulu futhi inebhendi eqinile ye-ultraviolet eduze kuka-258 nm (ukufakwa kwe-leucomethylene blue ku-PubChem, CAS 613-11-6). Inani lama-proton ekusabeleni okuyingxenye lincike ku-pH, ngoba uhlobo oluncishisiwe luthola ama-proton endaweni ene-asidi (amanani e-pKa alinganiselwe asondele ku-4.5 no-5.8). Izimo ezintathu zihlanganisa ibanga elisetshenziswa ngokujwayelekile:

MB(+) + 2 e(-) + H(+) <=> LMB, okuluhlaza okwesibhakabhaka <=> okungenambala (eduze kwe-pH engathathi hlangothi, 1 proton)

MB(+) + 2 e(-) + 2 H(+) <=> LMBH(+), okuluhlaza okwesibhakabhaka <=> okungenambala (okune-asidi ngokulingene, 2 protons)

MB(+) + 2 e(-) + 3 H(+) <=> uhlobo lwe-leuco olunama-proton amabili engeziwe (okune-asidi enamandla, 3 protons)

Zonke lezi zindlela ezintathu zokubhala zichaza ipheya efanayo ngaphansi kwezimo ezihlukene zokuthola ama-proton, okuyiphuzu elidingidwa ngokuhlelekile emibhalweni yokuziphatha kwe-redox kodayi be-thiazine. Ukuncika ku-pH kulandela isibalo se-Nernst se-Ox + mH(+) + 2e(-) <=> Red, okunikeza ukuthambeka okucishe kube ngu-29.6, 59.2, noma 88.7 mV ngeyunithi ngayinye ye-pH uma m = 1, 2, noma 3. Ukuthambeka okulinganisiwe okuseduze kuka-28, 58, no-87 mV ngeyunithi ngayinye ye-pH kuqinisekisa lokhu kwabiwa, ngakho i-potenshali ebikiwe ngaphandle kwe-pH yayo ayinancazelo.

Lokho isibalo esikutshela umenzi wezingxube

Amaqiniso amathathu avela ku-stoichiometry. Okokuqala, ama-electron amabili nge-molecule ngayinye asho ukuthi i-methylene blue iyinkomba nomlamuli wama-electron amabili, hhayi umthuthi we-electron eyodwa, ekusabeleni kwayo sekukonke. Okwesibili, ama-proton ayabamba iqhaza, ngakho i-potenshali ye-formal iyashintsha ne-pH njengoba kuchaziwe ngenhla. Okwesithathu, i-potenshali ye-formal ku-pH 7 iseduze kuka-+0.011 V uma iqhathaniswa ne-electrode ye-hydrogen ejwayelekile (cishe +0.53 V ku-pH 0), okubeka leli pheya phakathi kwama-oxidant athambile: linamandla anele okwamukela ama-electron kubanikeli abahle njenge-NAD(P)H noma i-ascorbate, kodwa libuthaka ngokwanele ukuba liwanikeze i-oksijini encibilikisiwe noma izikhungo ze-ferric. Yilesi sikhundla esiphakathi nendawo esenza udayi ujikeleze esikhundleni sokubambeka kolunye uhlangothi.

Ukuhlangana kwengeza enye inselele. Ngaphezu cishe kwe-micromolar eyikhulu emanzini, ngokuhambisana nenani elibikiwe le-constant yokuhlukana kwe-monomer ne-dimer eliseduze kuka-170 kuya ku-250 uM ku-pH 7, ama-cation asesimweni se-oxidation anqwabelana abe ama-dimer namaqoqo amakhulu, nebhendi yokumunca eshintshele eduze kuka-610 kuya ku-615 nm. Ngakho i-spectrum enesiqongo esingekho endaweni elindelekile ingase ibonise ukuqoqana, hhayi ukungcola. Qala ngokuhlanza ingxube ngokwengeza uketshezi ukuze wehlise ukuhlangana, bese uyahlulela.

Izimo eziqhuba uhlangothi ngalunye

Ithebula elingezansi liyisethenjwa somsebenzi waselabhorethri. Ukuncishiswa kudinga umnikeli wama-electron; ukubuyiselwa ku-oxidation kudinga umamukeli wama-electron, futhi umoya uvame ukwanele.

Konke okufakwe ethebuleni kulandela isibalo esifanayo. Kushintsha amandla aqhuba ukusabela kuphela. Yilokho okushiwo ukuthi leli pheya liyabuyiseleka emuva: indlela iyafana, ihanjwa ezinhlangothini eziphambene ngaphansi kwezimo eziphambene.

Ibhodlela eliluhlaza okwesibhakabhaka, lichaziwe

Indlela lo mbukiso osebenza ngayo kufanele ichazwe ngokusobala ngoba ubonisa leli pheya ngesilinganiso esincane. Esixazululweni se-glucose esine-alkali, i-base ikhuthaza ukuguquka kwe-glucose ibe yi-enol, bese i-enediolate evelayo inciphisa i-methylene blue ibe yi-leucomethylene blue, ngakho iflaski liphelelwa umbala. Ukunyakazisa kuncibilikisa i-oksijini evela esikhaleni somoya esingenhla koketshezi, i-oksijini ibuyisela uhlobo lwe-leuco ku-oxidation, bese umbala oluhlaza okwesibhakabhaka ubuya. Ukuma kunganyakazi kuqeda i-oksijini encibilikisiwe eduze kwendawo yokusabela engaphezulu, bese i-glucose iphinda inqobe. Umjikelezo uyaphindeka kuze kuphele i-glucose, futhi ukunyakazisa ngakunye kuyisibalo se-Nernst esibonakalayo: khuphula umsebenzi we-oxidant bese ukulingana kugudlukela ngasembaleni oluhlaza okwesibhakabhaka.

I-radical ephakathi

Ukusabela sekukonke kudlulisa ama-electron amabili, kodwa izinyathelo eziyisisekelo zidlulisa elilodwa ngesikhathi. Phakathi kwe-cation eluhlaza okwesibhakabhaka nohlobo lwe-leuco olungenambala kukhona i-radical ye-semiquinone ephakathi nendawo, ngokuvamile eguquka ngokusabela kwe-disproportionation ibuye ibe yileli pheya esikhundleni sokunqwabelana. I-potenshali yayo ye-electron eyodwa eseduze kuka-minus 0.23 V ku-pH 7 iphansi kakhulu kunendawo emaphakathi yokudluliselwa kwama-electron amabili sekukonke, yingakho i-radical ihlala iwuhlobo olunobuningi obuncane esimweni esizinzile. Ibalulekile ngezizathu ezimbili. Lapho ukhanyiswa, udayi ufinyelela ezimweni ezivusiwe ezivula izindlela zama-radical, yingakho izixazululo ze-methylene blue zizwela ekukhanyeni futhi yingakho i-photochemistry kufanele ifakwe kunoma iyiphi inqubo yokuhlola ukuzinza. Futhi lapho ukuhlangana kuphezulu, uhlobo olusesimweni se-oxidation lwakha ama-dimer, okushintsha i-spectrum namazinga okusabela abonakalayo ngaphandle kokushintsha ipheya eyisisekelo. Akukho kulawa maqiniso okuphazamisa ukubuyiseleka emuva. Womabili achaza okubonwayo obekungase kubonakale njengokungabuyiseleki emuva.

Izinhlobo ezihlobene ezisuswe amaqembu e-methyl zishintsha isikali

Susa amaqembu e-methyl ezingalweni ezimbili ze-dimethylamino bese ipheya lisala likhona kodwa linezakhiwo ezishintshile. Isiqongo sokumunca sigudluka njalo sibheke ohlangothini oluluhlaza okwesibhakabhaka njalo lapho kususwa iqembu le-methyl: i-methylene blue eduze kuka-664 nm, i-Azure B eduze kuka-654, i-Azure A eduze kuka-630, i-Azure C eduze kuka-615, ne-thionine eduze kuka-600 nm. I-Azure B, entula iqembu elilodwa le-methyl, iwuhlobo oluhlobene olusondele kakhulu: ingumkhiqizo omkhulu wokuguqulwa kwe-methylene blue emzimbeni kanye nokungcola okubhaliwe ezintweni ze-methylene blue. I-Azure A ne-Azure C ziqhubeka nochungechunge ngohlaka olufanayo olusebenza ku-redox. I-thionine, lapho womabili amaqembu e-amino esuswe wonke amaqembu e-methyl, isekugcineni ne-potenshali ye-formal eseduze kuka-+0.06 V ku-pH 7 uma iqhathaniswa ne-methylene blue eku-+0.011 V, futhi incishiswa kalula ngokuphawulekayo. Ama-potenshali e-redox kulo lonke uchungechunge ancike endaweni yesixazululo naku-electrode, ngakho qhathanisa amanani kuphela ngaphansi kwezimo ezifanayo. Yingakho ukuhlonza izinhlobo zokungcola kuyindaba ye-redox, hhayi nje ukuphawula ibhokisi lokuhlanzeka. Amaphesenti ambalwa e-Azure B asho amaphesenti ambalwa epheya ye-redox ehlukile ebhodleleni, futhi i-azure B njengokungcola nomkhiqizo wokuguqulwa emzimbeni ichaza ukuthi leyo ngxenye ilawulwa kanjani.

Lapho ibhayoloji ingena khona

Ngaphakathi kwengqamuzana legazi elibomvu, i-NADPH inciphisa i-methylene blue ibe yi-leucomethylene blue, bese uhlobo lwe-leuco ludlulisela ama-electron ku-ayoni ye-heme esesimweni se-ferric, lubuyisele i-hemoglobin esimweni se-ferrous. Lokho kudluliselwa kwe-electron okukodwa kuyisisekelo samakhemikhali sokusetshenziswa kwe-methylene blue ku-methemoglobinemia etholakele. Konke okulandela lokho kudluliselwa, ukuguqulwa kwamandla emzimbeni, ukugeleza kwama-electron kuma-mitochondria, nanoma yimuphi umphumela webhayoloji, kungaphansi kokuthuthwa kwama-electron kuma-mitochondria futhi kushiywe lapho ngenhloso.

Thenga ipheya, hhayi umbala kuphela

Udayi we-redox muhle kuphela ngokwezinga lezimfuneko zawo. Ukuhlanzeka okuphezulu kubalulekile ngoba i-methylene blue engeyona eye-USP ngokuvamile ingeyezinga lendwangu, iqukethe i-Azure B, izinsimbi ezisindayo, noma izincibilikisi ezisele ezishintsha ukufundwa kwe-redox futhi zifiphaze amaphuzu okuphela kokusabela; akukho nqubo yokufaka umbala eyenzelwe ukuhlola lokhu. Abathengisi abaningi abathi bathobela i-USP bahlola izinsimbi ezisindayo kuphela bese bethi sebephumelele. Ukuthobela okuphelele kuhlanganisa ukuhlonza, ukunqunywa kwenani lesithako, ukungcola kwe-organic, izincibilikisi ezisele, ukungcola kwezakhi, insalela ngemva kokushiswa, imingcele yamagciwane, nama-endotoxin amabhaktheriya, futhi indlela yokukhetha i-methylene blue yezinga lemithi ichaza indlela yokufunda lawo madokhumenti. I-Blupreme isebenza nomkhiqizi we-methylene blue yezinga lemithi, ihlola zonke izimfuneko ze-USP, futhi ishicilela i-COA ephelele. Lapho umbala uyisilinganiso, lawo madokhumenti ayingxenye yethuluzi lokulinganisa.