Preparation Of Nanodots-layered Double Hydroxide Composite Toward Bioimaging And Cancer Therapy

Layered double hydroxides(LDHs),a typical 2D layered inorganic nanomaterial,have been widely used as drug delivery and drawn considerable attention in biomaterial,due to their excellent biocompatibility and its adjustability of cations in host layer,a strong loading capacity toward drug and diversity of interlayer guest.In this dissertation,we loaded photosensitizer and fluorescent carbon dots onto LDH nanosheet to improve its fluorescence imaging behavior and PDT performance because of its large surface and positive host layer;we doped Bi element into the host layer and then reduced it to Bi nanodots which have PTT effect and PA imaging performance.The major contents are shown as follows:1.CDs-Ce6/LDH composite for simultaneous fluorescence imaging and photodynamic therapyWe designed and prepared LDHs ultrithin nanosheets as a delivery vehicle to load both photosensitizer(Chlorin e6,Ce6)and CDs though electrostatic interaction.TEM image,UV-vis and FT-IR spectroscopy confirm Ce6 molecules and CDs are accommodated onto LDHs ultrithin nanosheets,with accurately-controlled CDs/Ce6 ratio.When the ratio of CDs:Ce6 is 2:1,the FRET efficiency is 90%and the emission intensity of CDs-Ce6/LDH material is?90 folds stronger than that of pristine Ce6.CDs-Ce6/LDH composite exhibits a significiantly fluorescence performance.The photostability and single oxygen production efficiency of Ce6 is also improved after loaded on the surface of LDH nanosheet.In vitro studies performed with Hela cells reveal a satisfactory cellular imaging and PDT effectiveness of CDs-Ce6/LDH.2.Bi nanodots-LDH composite for photoacoustic imaging and photothermal therapyIn this work,we doped Bi3+ into LDH layer because of the adjustability of cations in host layer.And then we reduced Bi3+ into Bi nanodots on the surface of LDH.The amount of Bi dots can be regulated via changing the doping amount ratio of Bi.When the ratio reachs 50%,the surface is full with Bi dots and photothermal conversion efficiency is 30.93%.A satisfactory in vitro PTT performance is obtain with cell.When incubated with 100 ?g/mL Bi-LDH and an irradiation(808 nm,1W/cm2,5 min),76.5%cell was killed.And when the irradiation time prolonged to 10 min,the cell viability decrease to 9.8%.Because of its strong absorption in NIR,it also has an ability for PA imaging.In summary,LDH based theranostic materials have been developed for bioimaging and phototherapy,because of LDH's strong loading capacity and adjustability of cations in host layer.