Synthesis Of PBA-Targeted Polydopamine Coated LAP-Fe₃O₄ Nanoparticles For Multimodal Imaging Guided Photothermal Therapy

The development of theranostic nanoplatforms with accurate diagnosis and effective therapy performance is crucial for precision medicine applications.Herein,we developed a novel targeted theranostic nanoplatform for magnetic resonance（MR）and photoacoustic（PA）imaging-guided photothermal therapy（PTT）of cancer cells overexpressing sialic acid（SA）.Firstly,laponite（LAP）-stabilized Fe₃O₄ nanoparticles（NPs）with a high r2 relaxivity were synthesized by a coprecipitation method,and then polydopamine（PDA）was coated to endow the NPs with photothermal effect and PA contrast effect,followed by the modification of PEGylated phenylboronic acid（PEG-PBA）to improve colloidal stability and to render the particles with tumor-targeting specificity to SA-expressing cancer cells.The results of FTIR,TGA and TEM proved that core-shell structure of LAP-Fe₃O₄@PDA-PEG-PBA nanoparticles have been successfully prepared with a size of 47.5 nm.It has good colloidal stability,high relaxation rate（266.1 m M-1s-1）and excellent photothermal performance（from 22℃ to 56℃ in five minutes）.It has been demonstrated that LAP-Fe₃O₄@PDA-PEG-PBA NPs have good biocompatibility,specifically recognized and enriched overexpressing SA mouse breast cancer 4T1 cells in vitro experiments,meanwhile significantly enhanced photothermal therapy effect at 808 nm laser irradiation.It has been proved that LAP-Fe₃O₄@PDA-PEG-PBA NPs actively enrich the tumor site and has excellent MR/PA/thermal imaging effect in vivo imaging experiment.At 96 h,the LAP-Fe₃O₄@PDA-PEG-PBA NPs have metabolized.The LAP-Fe₃O₄@PDA-PEG-PBA NPs can be significantly inhibited tumor growth,reduced lung metastasis,improved survival rate and low toxicity under 808 nm laser.In sum,the developed LAP-Fe₃O₄@PDA-PEG-PBA NPs could be used as a theranostic nanoplatform for sensitive MR/PA imaging and effective photothermal therapy of different types of SA-overexpressing tumors.It was created new ideas for accurate diagnosis and efficient treatment of tumors...