H-Nanoaggregates Of Heptamethine Cyanine For Imaging-Guiding Photothermal Cancer Therapy

The lives of human being has been threatened by cancers.The applications to treat cancers include surgery therapy,chemotherapy and radiotherapy which have effects on cancer treatment,some side effects occurred meanwhile.Phototherapy draws more attention to researchers because of its minimum invasiveness,easy procedure,quick recovery and little side effect.There are many applications of photosensitizers in PTT,most of them are inorganic materials.Due to the inorganic photothermal agents often limited by the difficult metabolism and uncontrollable toxicity,the development of the lower toxicity and better biocompatiablity photothermal therapy agents attracts attentions to the researchers.As an diagnosis drug approvalled by FDA,Indio cyanine(ICG)can be used to photothermal therapy because of the near infrared absorbance and photothermal effect.However,limited by the low photothermal conversion efficiency of ICG and its poor photothermal stability,the applications of ICG to PTT often need to be encapsulated by macromolecules or chelated by metal ions.So the potential toxicity is unpredictable with introducing these matters.We design photothermal nanomaterials from the perspective of supramolecular assembly to avoid the introduction of other substances.Looking back in the history of cyanine dyes,the phenomenon of Jaggregation and H-aggregation of cyanine dyes can increase the size of nanoparticles and encourage them targeting tumor sites passively through the EPR effect,which provides an strategy for us to design PTT photosensitizers.Since J-aggregation’s discovery,it has attracted much attention because its fluorescence enhancement promoting fluorescence imaging,while H-aggregation has received little attention due to its quenched fluorescence weakening the capability of fluorescence imaging.The spectrum of H-aggregation is hypsochromic shifted and requires higher excitation energy,but its fluorescence is quenched.We can reasonably assume that the part of the quenched fluorescence may be released as heat.Therefore,we have introduced groups with different planarity to induce H-aggregation of heptamethine cyanine to improve the photothermal effect,so that heptamethine cyanine molecules can be efficiently applied to tumor photothermal therapy.