Research On Imaging-guided Synergistic Tumor Therapy Based On Polydopamine Nanocarriers

PTT employs PTCAs and NIR light to convert laser into heat to cause irreversible damage of tumor tissue.However,when PTT is used as an independent treatment,it will face the problem of uneven distribution of heat in the tissue,further leading to unsatisfactory treatment results.Therefore,PTT usually combined with other therapies through different mechanisms to provide a better treatment effiency,such as radiotherapy,gene therapy,immunotherapy,gas therapy etc.In order to achieve precise and visual guidance in treatment,multiple diagnostic imaging technologies which using specific probes or contrast agents has attracted much attention in recent years,known as diagnostic therapeutics.Imaging contrast agents can be loaded or doped into nanomaterials through a rational design and synthesis of nanomaterials to guide cancer treatment in real time.Among the emerging multi-functional biomaterials,PDA,taking advantages of good biocompatibility,strong near-infrared absorption capacity and facile modification,which could not only be used as a good photothermal agent but also an ideal nano-carrier.Herein,we have designed two theranostics nanoplatforms based on PDA for synergistic tumor therapy.In the first project,we designed a nanoplatform based on PDA-loaded carbon quantum dots（fluorescent imaging agent）and resquimod（immune adjuvant）,Which named as“PDA-PEG-R848-CDs”.Combined with check point blockade strategy,which was promising for eliminating primary tumors with light irradiation as well as inhibiting distant tumors without PTT.However,deep tumor could not be eliminated because of the depth limitation.Interestingly,gas molecules have better diffusion ability to deep tissue.Motivated by the inherent drawback of light and diffusion properties of gas molecules,we designed the nanorattles based on SO₂ prodrug doped yolk shell structure of gold nanorods@mesoporous polydopamine（GNRs@PDA-BTS）for exogenous（light）and endogenous（p H）dual stimulation release of SO₂.The synthesized GNRs@PDA-BTS nanoparticles were used for photothermal therapy to ablate outside tumor tissue and to perform gas therapy inside tumor,which is expected to be used for“collusion inside and outside”of superficial and deep tumors.