Introduction: Herein, we report a microfluidic method for a novel polylactic-co-glycolic acid (PLGA) nanoparticle synthesis coated with Carbon dots (CDs) for encapsulation of the Fluorouracil (5FU) as the anti-cancer drug. PLGA is an FDA copolymer for drug-delivery systems(DDS) because of suitable properties such as controllable degradation rate and biocompatibility. CDs is a star rising of carbon nanomaterials used as the bioimaging probe because of excellent optoelectronics properties and NIR(Near-infrared) upconversion. Thus we introduced a novel theranostics DDS. In the fight against cancer, there is an urgent need to deliver drugs to tumor cells without the harmful effects of the drugs on healthy cells. For this purpose, the encapsulation is an effective way that not only reduces the immunological effects of the drugs but also improves the long-term circulation of them in the bloodstream. Microfluidic systems by putting together two incompatible liquids can synthesis particles in micro-nano scale range that carry large amounts of the drugs and release them in a long-term period. Fluorouracil(5FU) is one of the most frequently used drugs to treat cancer. 5FU is a treatment for many types of cancer including breast and colon cancers, but it has some drawback such as thinning of hairs, hand-foot syndrome, neutropenia, etc. Development of new methods for efficient delivery is drawing attention to improve treatment effects by expanding bioavailability and specificity of the therapeutic agent as long as minimizing side effects of the drug. In this report, by employing a novel PLGA nanoparticle coated with CDs, we introduced a theranostics nanocarrier to deliver 5FU to cancer cells while preventing 5FU to impact on other cells.
Methods: PLGA copolymer (75:25/MW:6 kDa) and di-Ammonium hydrogen citrate were purchased from Sigma. Dimethyl sulfoxide(DMSO), silicone oil and span 80 were obtained from Merck. HepG2 cancer cell was purchased from Pasteur Institute, Tehran, Iran.
One of the microfluidics methods that can result in the particles in nano-scale size is extraction. In this method, PLGA 1wt% copolymer and 500 μM 5FU dissolved in DMSO solvent. One pump contains PLGA-5FU@DMSO solution, and another includes water that produces droplets by a T-junction in a continuous oil-phase of silicone oil/1% span 80 as a surfactant agent. Preparation of micro-channels was done by PDMS chip. Span 80 as a surfactant agent was used to prevent the sticking of PLGA/DMSO into the walls or diffusion of PDMS into the solution. It is proved that the ratio of 1 to 2 mlh-1 flow rate of water to .5 mlh-1 5fu-PLGA@DMSO results in nanoparticles with an average diameter at 125nm. Scanning electron microscope was done to proving the synthesis of nanoparticles. CDs synthesis through one step hydrothermal treatment of di-Ammonium hydrogen citrate as the source of carbon. Finally, luminescent CDs was introduced to the solution of PLGA nanoparticles and based on a self-assembly mechanism, interaction between CDs and PLGA nanoparticle were done. In-vitro cytotoxicity and bioimaging of 5fu-PLGA nanoparticles against 3D-culture of the HepG2 cancer cell line were evaluated. The amount of 5FU in the nanoparticles was determined by measuring the absorbance of the solution at 590 nm using a UV-Vis spectrophotometer. Drug release from PLGA nanoparticles was measured as previously reported.
Results: Drug targeting systems need a passive targeting that called enhanced permeation retention(EPR). For this purpose, we need to have NPs in the size of 50 nm to 200nm. By adjusting the flow rate of water and 5FU-PLGA@DMSO streams, We produced the nano-scaled particles. Drug release test of nanoparticles in different pH exhibited an increase of release rate with the decrease of media pH. This may be due to the change in the electric charge of carbon dots and then the removal of carbon dots from the surface of the nanoparticle, as a result, increase in the drug release was observed. In-vitro cell viability test with 5FU encapsulated Nanoparticles against HepG2 cells exhibited 3% viable cells at 200 μM concentration. The continuous decrease of cell density indicated the slow release of cancer drugs from the Nanoparticles. In-vitro Fluorescent bioimaging of HepG2 cells using CDs@PLGA nanoparticles showed considerable potential for a theranostics nanocarrier.
Conclusion: In this report, we focused on the producing of a drug-loaded PLGA nanoparticle theranostics system using a microfluidic system.
Keywords: Microfluidics – PLGA – Cancer treatment – 5FU