The Research Of Hyaluronic Acid-Based Multifunctional Nanoparticles For Tumor Diagnosis And Therapy

The construction of multifunctional nanoparticles used in rapid diagnosis and therapy of cancer was one of the flash points of cancer treatment research.Hyaluronic acid(HA)was an important component of extracellular matrix with the characters of excellent biocompatibility and biodegradability.In addition,HA could efficiently increase the endocytosis of some tumor cells via specificly binding the CD44 receptors overexpressed by them.These advantages enabled HA as an excellent surface modification and drug carrier material.In this research,HA-based multifunctional nanoparticles were fabricated for cancer diagnosis and treatment.The main works contained the following two parts:1.Multifunctional nanoparticle was drawing increased attention in tumor diagnosis and therapy.Besides the size and surface characteristics,the morphology of nanoparticles has been identified as a key factor influencing circulation time,biodistribution,targeting and cellular uptake.There were some specific characteristics of gold nanoparticles,such as non-toxic,large-scale synthesis with easy method,could be easily modified and had special optical and electronic properties,which could meet the vast requirement in tumor diagnosis and therapy.In this work,two morphologies of nanoprobes were fabricated using gold nanorods(AuNRs)and gold nanospheres(AuNSs).The AuNRs showed averaged 50 nm in length and 12 nm in width and the AuNSs showed 20 nm in diameter.Thiolated-hyaluronic acid labeled with nile blue(HS-HA-NB),a near-infrared(NIR)fluorescence dye,was coated on the surface of the gold nanoparticles to form stable nanoprobes(AuNR@HS-HA-NB,AuNS@HS-HA-NB).Owing to the excellent biocompatibility and biodegradability of HA,the combined nanoprobes were quite stable in phosphate buffer with pH range from 4 to 8 and the 80%FBS treatment.Human breast carcinoma(MCF-7)cell cytotoxicity tests showed the cytotoxicity of gold nanoprobes significantly decreased after coated by HS-HA-NB.In the MCF-7 cells image experiment,compared with the spherical nanoprobes,the rod-shaped nanoprobes enhanced the effective endocytosis and led to rapid image,which might attribute to the longitudinal axis of rod-shaped nanoprobes have a larger contact area with the cells membrane.The targeting ability of HA to CD44 receptor-overexpressing cancer cells was also verified via competitive inhibition experiment.Furthermore,after NIR light irradiation,severe MCF-7 apoptosis was observed with AuNR@HS-HA-NB existed.The above research proved AuNR@HS-HA-NB nanoprobes could realize intracellular fluorescent light-up and photothermal cancer therapy.2.Chemotherapy had been widespreadly used in cancer treatments.Drug resistance and insufficient cancer cellular uptake were the main obstacles in the cancer chemotherapy,which could result in an inferior therapeutic outcome.It was attractive that the drug resistance of tumor could be eliminated through combination the photothermal therapy with hyperthermia effect.In this research,AuNRs loaded HA(HA-Cys@AuNR)nano gels were crosslinked by cystamine(Cys).Then doxorubicin(DOX)was incorporated by electrostatic interaction to form HA-Cys@AuNR@DOX nanogels.The DOX loading capacity and encapsulation efficiency were 0.5 ±0.017%and 51.9 ±3.5%respectively.The AuNRs-free HA-Cys@DOX nanogels were prepared as control with DOX loading capacity 0.5 ±0.014%and encapsulation efficiency 56.8±3.4%.Because of the existence of disulfide bonds in Cys,after treatment with glutathione(GSH)for 4 h,the final similar cumulative DOX releases of 72.4%and 69.9%were acquired for HA-Cys@DOX and HA-Cys@AuNR@DOX nanogels respectively.Cell cytotoxicity tests revealed the HA-Cys@DOX and HA-Cys@AuNR@DOX had the similar cytotoxicity to drug-sensitive MCF-7 cells and showed no effects in MCF-7 ADR because of the greater resistance to DOX.Surprisingly,with the treatment of HA-Cys@AuNR@DOX under the NIR laser irradiation,the photothermal treatment of AuNRs could overcome drug resistance and promote cell apoptosis in MCF-7 ADR cells.The result of fluorescence microscope images further indicated that enlarged the accumulation and retention of DOX inside the drug-resistant MCF-7 ADR cells,which might due to hyperthermia of gold nanorods changed the permeability and fluidity of plasma membrane.Competitive inhibition experiment proved the target ability of HA-based nanogels to MCF-7 cells.Thus,we successfully synthesized the HA-based multifunctional nanogels with the targeted synergistic chemo-photothermal therapy ability to resolve drug resistance of specific cancer cells.The design of HA-based nanoprobes and drug nanocarriers provided a new idea in the research of multifunctional nanoparticles used in tumor diagnosis and therapy.