TY - JOUR
T1 - Development of novel poly-l-lysine-modified sericin-coated superparamagnetic iron oxide nanoparticles as siRNA carrier
AU - Kara, Goknur
AU - Malekghasemi, Soheil
AU - Ozpolat, Bulent
AU - Denkbas, Emir Baki
N1 - Funding Information:
Goknur Kara was supported by the Scientific and Technological Research Council of Turkey (TUBITAK), (grant no: 1059B141700104 ), under the 2214-A International Doctoral Research Fellowship Program.
Publisher Copyright:
© 2021 Elsevier B.V.
PY - 2021/12/5
Y1 - 2021/12/5
N2 - Small interfering RNA (siRNA) is a promising therapeutic modality, however, its successful clinical application is still challenging due to the lack of safe and efficient carrier systems. Superparamagnetic iron oxide nanoparticles (SPIONs)-based drug or gene carrier systems have displayed tremendous promise in nanomedicine. They possess intrinsic unique superparamagnetism that provides them to be concentrated in the targeted therapeutic site of action where an external magnetic field is applied. SPIONs can be also designed as theranostic agents to achieve simultaneous therapeutic and diagnostic purposes. Despite these favorable features, SPIONs are colloidally unstable and can be easily eliminated in the circulation. More importantly, the toxicological concerns associated with SPIONs, which often lead to the generation of reactive oxygen species (ROS), need to be thoroughly considered. Various types of polymers have been proposed so far to cover the surface of SPION to overcome these disadvantages. Silk protein, sericin can be ideal as a coating material due to its high biocompatibility, good biodegradability, and in vivo stability. In terms of the development of SPIONs as siRNA carriers, to the best of our knowledge, no protein was used as the coating material, and SPIONs coated with sericin have not been reported in the literature as a drug or gene carrier system. The present study aimed to design and develop a novel siRNA carrier system based on SPIONs. We prepared and characterized a nanomaterial comprised of SPIONs covalently coated with a biocompatible protein, sericin (Ser), and modified with a cationic polymer, poly-L-lysine (PLL) to incorporate the negatively charged siRNA. Transmission electron microscopy (TEM) images revealed that obtained nanoparticles had narrow size distribution with spherical shape and coated nanoparticles presented black spheres in the SPION core surrounded with a gray layer, which indicated sericin coating. Adding PLL to Ser-SPIONs did not cause any dramatic change in nanoparticle size whereas it provided a net positive charge to the particles. Additionally, electron spin resonance (ESR) analysis showed that sericin coating and PLL modification did not efface the superparamagnetic properties of the particles. We successfully attached the control-siRNAs to the surface of PLL/Ser-SPIONs, forming siRNA-PLL/Ser-SPION nanoplatforms and achieving high siRNA binding efficiencies ranged between 81.90% and 93.50%. The ability of SPIONs-based nanocarriers to fulfill their promises in clinical use depends on keeping their nanotoxicity properties to a minimum. All the nanoparticle formulations tested herein were found to be biocompatible against non-cancerous and cancer cells by cytotoxicity assays. We also investigated the effect of resulting bare particles, PLL/Ser-SPIONs, on the clonogenicity of cancer cells. According to the results, the cells exhibited colony formation ability depending on the concentration of the nanoparticles and PLL/Ser-SPIONs did not block clonogenicity, except at very high doses. Taken together, our findings imply that these new PLL/Ser-SPIONs can be considered as a safe and promising carrier candidate to be used and developed for further siRNA-based applications.
AB - Small interfering RNA (siRNA) is a promising therapeutic modality, however, its successful clinical application is still challenging due to the lack of safe and efficient carrier systems. Superparamagnetic iron oxide nanoparticles (SPIONs)-based drug or gene carrier systems have displayed tremendous promise in nanomedicine. They possess intrinsic unique superparamagnetism that provides them to be concentrated in the targeted therapeutic site of action where an external magnetic field is applied. SPIONs can be also designed as theranostic agents to achieve simultaneous therapeutic and diagnostic purposes. Despite these favorable features, SPIONs are colloidally unstable and can be easily eliminated in the circulation. More importantly, the toxicological concerns associated with SPIONs, which often lead to the generation of reactive oxygen species (ROS), need to be thoroughly considered. Various types of polymers have been proposed so far to cover the surface of SPION to overcome these disadvantages. Silk protein, sericin can be ideal as a coating material due to its high biocompatibility, good biodegradability, and in vivo stability. In terms of the development of SPIONs as siRNA carriers, to the best of our knowledge, no protein was used as the coating material, and SPIONs coated with sericin have not been reported in the literature as a drug or gene carrier system. The present study aimed to design and develop a novel siRNA carrier system based on SPIONs. We prepared and characterized a nanomaterial comprised of SPIONs covalently coated with a biocompatible protein, sericin (Ser), and modified with a cationic polymer, poly-L-lysine (PLL) to incorporate the negatively charged siRNA. Transmission electron microscopy (TEM) images revealed that obtained nanoparticles had narrow size distribution with spherical shape and coated nanoparticles presented black spheres in the SPION core surrounded with a gray layer, which indicated sericin coating. Adding PLL to Ser-SPIONs did not cause any dramatic change in nanoparticle size whereas it provided a net positive charge to the particles. Additionally, electron spin resonance (ESR) analysis showed that sericin coating and PLL modification did not efface the superparamagnetic properties of the particles. We successfully attached the control-siRNAs to the surface of PLL/Ser-SPIONs, forming siRNA-PLL/Ser-SPION nanoplatforms and achieving high siRNA binding efficiencies ranged between 81.90% and 93.50%. The ability of SPIONs-based nanocarriers to fulfill their promises in clinical use depends on keeping their nanotoxicity properties to a minimum. All the nanoparticle formulations tested herein were found to be biocompatible against non-cancerous and cancer cells by cytotoxicity assays. We also investigated the effect of resulting bare particles, PLL/Ser-SPIONs, on the clonogenicity of cancer cells. According to the results, the cells exhibited colony formation ability depending on the concentration of the nanoparticles and PLL/Ser-SPIONs did not block clonogenicity, except at very high doses. Taken together, our findings imply that these new PLL/Ser-SPIONs can be considered as a safe and promising carrier candidate to be used and developed for further siRNA-based applications.
KW - PLL
KW - Sericin
KW - siRNA
KW - siRNA carrier system
KW - Superparamagnetic iron oxide nanoparticles
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U2 - 10.1016/j.colsurfa.2021.127622
DO - 10.1016/j.colsurfa.2021.127622
M3 - Article
AN - SCOPUS:85115891063
SN - 0927-7757
VL - 630
JO - Colloids and Surfaces A: Physicochemical and Engineering Aspects
JF - Colloids and Surfaces A: Physicochemical and Engineering Aspects
M1 - 127622
ER -