Preparation Of Indocyanine Green Nanocomposites And Their Biomedical Application

Indocyanine green(ICG)is a commonly near infrared(NIR)imaging agent in clinical,with outstanding phototherapy performance for tumor diagnosis treatment and therapy,as well as bacterial infection.However,ICG suffers from multiple shortcomings of poor aqueous instability in the physiological environment,short halflife and rapid body clearance,which often hinder its clinical biomedical application.In addition,the clinical application single-mode phototherapy has been restricted due to the low ability for anti-bacteria or anti-tumor,which also induced the thermal damage of surrounding tissues or caused tumor recurrence.In order to improve the effect of phototherapy,there is an urgent need for developing multifunctional drug delivery system to achieve high efficiency of tumor treatment and bacterial killing.To solve the above question,a series of multifunctional collaborative ICG drug delivery system systems for tumor diagnosis and treatment as well as bacterial infection were produced in this paper for expanding the biomedical application of ICG.Firstly,ICG nanoparticles(ICG NPs)were constructed by supercritical antisolvent(SAS)process.A full factor experiment was employed for understanding the effect of process parameters.Then,a cationic polymer poly-l-ornithine(PLO)was modified on the surface of ICG NPs(ICG-PLO NPs)for stability improvement,and the physicochemical properties and photothermal properties of ICG-PLO NPs were investigated.This novel process successfully resulted in uniform spherical-shaped ICG-PLO NPs with a mean particle size of 35.5 nm.After coated,zeta potential of ICG-PLO NPs from-15.6 m V turned to 16.3 m V,and with a higher stability after stored in water for 14 days.Moreover,ICG-PLO NPs showed excellent fluorescence imaging effect and improved the effect of ICG phototherapy in vitro and in vivo.Secondly,to avoid the problems of phototherapy with lower treat tumor effect and high side effects of chemotherapy,and the lower drug concentration in tumor site,targeted drug nanoparticles were produced for tumor theranostic.A typical anticancer drug,paclitaxel(PTX)and ICG nanocomposites(ICG/PTX NPs)were constructed bySAS method,the ratio of ICG showed 66.9 %,and the ratio of PTX showed 33.1 % in ICG/PTX NPs.Then,the ICG/PTX NPs were coated with a precursor of nitric oxide(NO)named poly-L-arginine(PLA)and a targeting polysaccharide hyaluronic acid(HA)on the surface of drug nanoparticles(ICG/PTX-PLA-HA NPs)has been firstly developed via layer-by-layer self-assembly technology.The multifunctional targeted nanoplatform resulted in a uniform spherical structure with 28.0 nm,possess an ultrahigh drug entrapment efficiency(EE)(ICG = 98.4 % ± 0.6 %,PTX = 97.7 % ± 0.7 %)and good photothermal conversion efficiency.ICG/PTX-PLA-HA NPs with an excellent production of NO and reactive oxygen species(ROS)in vitro,realized enhanced tumor-specific cellular uptake and excellent anti-tumor synergistic effect at low dose.Compared with single treatment,in vivo results showed that ICG/PTX-PLAHA NPs exhibited a significantly tumor growth inhibition based on the synergistic effect of phototherapy,chemotherapy and gas therapy.Finally,in order to solve the problem that phototherapy achieve low efficiency therapeutic efficacy for bacterial infection and expand the application of ICG,a novel drug delivery system based on nanoparticles were produced for antimicrobial combination treatment.At first,an antibacterial drug named Luteolin and ICG nanocomposites(ICG/Luteolin NPs)were prepared by SAS method and the effects of various process parameters on ICG/luteolin NPs were studied by full factor experiment,which showed that the optimal preparation conditions were as follows: CO2 flow rate of 40 g/min,pressure of 12 MPa,solvent flow rate of 0.5 mg/m L.Then,chitosan(CS)was used to modify the surface of ICG/Luteolin NPs(ICG/Luteolin-CS NPs),the EE of 99.1 % ± 0.4 % for ICG and the EE of 97.3 % ± 0.7 % for Luteolin and also showed outstanding photothermal effect.In vivo and vitro results indicated that ICG/LuteolinCS NPs displayed an effectively synergistic effect of phototherapy and chemotherapy,showing excellent antibacterial(almost to 100 %),anti-biofilm formation and antibiofilm effects.ICG/Luteolin-CS NPs based synergetic antibacterial system with good compatibility effectively inhibited Staphylococcus aureus wound infection and accelerate wound healing,and the relative wound healing rate in 8 days reaches 87 %.The results showed that the all-in-one phototherapeutic nanoplatform displayed excellent antibacterial,effective biofilm elimination and wound healing effects,which provided a promising method for the treatment of skin bacterial infection.In conclusion,we have successfully prepared ICG-PLO NPs,ICG/PTX-PLA-HA NPs and ICG/Luteolin-CS NPs based on SAS process and layer-by-layer self-assembly technology.These drug delivery systems not only improve the stability of ICG in vitro and in vivo,but also achieve efficient antibacterial and anti-tumor effect by combination of collaborative treatment methods,which provide a novel strategy for the future development of the ICG drug delivery system and biomedical application of ICG.