The combined impact of protein corona-free property of starch coated poly (methyl methacrylate) nanoparticles: Amylose content and surface charge

Purification processes of polymeric nanoparticles: How to improve their clinical translation?

Polymeric nanoparticles, as revolutionary nanomedicines, have offered a new class of diagnostic and therapeutic solutions for a multitude of diseases. With its immense potential, the world witnesses the new age of nanotechnology after the COVID-19 vaccines were developed based on nanotechnology. Even though there are countless benchtop research studies in the nanotechnology world, their integration into commercially available technologies is still restricted. The post-pandemic world demands a surge of research in the domain, which leaves us with the fundamental question: why is the clinical translation of therapeutic nanoparticles so restricted? Complications in nanomedicine purification, among other things, are to blame for the lack of transference. Polymeric nanoparticles, owing to their ease of manufacture, biocompatibility, and enhanced efficiency, are one of the more explored domains in organic-based nanomedicines. Purification of nanoparticles can be challenging and necessitates tailoring the available methods in accordance with the polymeric nanoparticle and impurities involved. Though a number of techniques have been described, there are no available guidelines that help in selecting the method to better suit our requirements. We encountered this difficulty while compiling articles for this review and looking for methods to purify polymeric nanoparticles. The currently accessible bibliography for purification techniques only provides approaches for a specific type of nanomaterial or sometimes even procedures for bulk materials, that are not fully relevant to nanoparticles. In our research, we tried to summarize the available purification techniques using the approach of A.F. Armington. We divided the purification systems into two major classes, namely: phase separation-based techniques (based on the physical differences between the phases) and matter exchange-based techniques (centered on physicochemical induced transfer of materials and compounds). The phase separation methods are based on either using nanoparticle size differences to retain them on a physical barrier (filtration techniques) or using their densities to segregate them (centrifugation techniques). The matter exchange separation methods rely on either transferring the molecules or impurities across a barrier using simple physicochemical phenomena, like the concentration gradients (dialysis method) or partition coefficients (extraction technique). After describing the methods in detail, we highlight their advantages and limitations, mainly focusing on preformed polymer-based nanoparticles. Tailoring a purification strategy takes into account the nanoparticle structure and its integrity, the method selected should be suited for preserving the integrity of the particles, in addition to conforming to the economical, material and productivity considerations. In the meantime, we advocate the use of a harmonized international regulatory framework to define the adequate physicochemical and biological characterization of nanomedicines. An appropriate purification strategy serves as the backbone to achieving desired characteristics, in addition to reducing variability. As a result, the present review aspires to serve as a comprehensive guide for researchers, who are new to the domain, as well as a synopsis of purification strategies and analytical characterization methods used in preclinical studies.

Thermo-sensitive amylase-starch double-layer polymer nanoparticles with self-polishing and protein corona-free property for drug delivery applications

Protein corona formation can lead to obstructive screening of targeting groups of nanoparticles (NPs). Also, the targeting groups are subjected to physiochemical interactions when exposed to solvents. Here, these two factors can influence NP targeting efficiency. Therefore, it is necessary to prepare a general method of preparing an anti-fouling NPs with protected targeting groups. Here, we designed α-amylase-starch double-layer coated poly (methyl methacrylate-co-acrylic acid) NPs (α-ams-SCMMA NPs), functionalized with aptamer targeting groups and doped with Tetrakis(para-hydraoxylphenyl) porphyrin (TPPOH) as a payload drug. Natural polysaccharide starch and enzyme α-amylase were applied here for thermo-sensitive activation of starch hydrolyzation in order to render the NPs' self-polishing from protein corona effects. During incubation with serum media, the protein corona was formed at the exterior shell of NPs, while the self-polishing process was activated to remove the "protein fouling" when the incubation temperature increased to 37 °C (body temperature). Mechanistically, the starch layer of α-ams-SCMMA NPs was readily hydrolysed by α-amylase, whereby the adsorbed protein corona could be efficiently eliminated and the targeting groups were then presented. With this unique self-polishing NP design, we believe our method can be applied for potential NP applications in cancer therepy due to excellent antifouling property and protected targeting groups.

Quantitative Analysis of Protein Corona on Precoated Protein Nanoparticles and Determined Nanoparticles with Ultralow Protein Corona and Efficient Targeting in Vivo

The protein corona on nanoparticles (NPs) is a critical problem that often screens the targeting molecules and becomes one of the key reasons for the lack of practical application in nanotherapy. It is critical to fully understand the mechanism of the nanoparticle-biological interactions to design the nanoparticle-based therapeutic agents. Some types of proteins can be precoated on the nanoparticles to avoid unwanted protein attachment; however, the ultralow level of protein corona is hard to achieve, and the relationship of the antifouling property of the precoated protein nanoparticles with protein conformation and protein-nanoparticle interaction energy has never been investigated. In this work, we provided the quantitative protein corona composition analysis on different precoated protein nanoparticles, and on the basis of the molecular simulation process, we found their antifouling property strongly depended on the interaction energy of the precoated protein-serum protein pair and the number of hydrogen bonds formed between them. Furthermore, it also depended on the nanoparticle-serum protein pair interaction energy and the protein conformation on the nanoparticle. The casein coated nanoparticle with the antifouling property was determined, and after aptamer conjugation and drug loading, they exhibited superior targeting and internalization behavior for photodynamic and photothermal therapy in vitro and in vivo. Our work adds to the understanding of the protein corona behavior of precoated protein nanoparticles, and the determined antifouling NP can potentially be used as a highly efficient nanodrug carrier.

Stealthy nanoparticles protect endothelial barrier from leakiness by resisting the absorption of VE-cadherin

Nanomaterial induced endothelial cell leakiness (NanoEL) is caused because nanomaterials enter the interstitial space of the endothelial cells and disrupt the endothelial cell-cell interactions by interacting with vascular endothelial cadherin (VE-cad). Whereas the NanoEL effect could cause controllable leakiness in cancer therapy, the gaps created by the NanoEL effect can make the cancer cells cross the endothelial barrier and produce side effects induced by using nanomedicine. In this paper, a series of ultralow protein corona nanoparticle is reported that can penetrate the endothelial cell junction without obviously interacting with the VE-cad and phosphorylating the tyrosine 658 (Y658) and tyrosine 731 (Y731) residues on VE-cad, thus preventing the VE-cad from being activated by Src kinase, and this avoids inducing of the NanoEL effect and cancer cell migration, regardless of particle material, density and surface charge. These findings provide a new idea for the design of novel nanoparticles without side effects and can maximize their cancer-killing effect.

Synthesis, characterization, and cytotoxicity of starch-encapsulated biogenic silver nanoparticle and its improved anti-bacterial activity

The present work reported synthesis, characterization, and biocompatibility of starch encapsulated silver nanoparticles (St-PF-AgNPs) and their antibacterial activity. The synthesis of St-PF-AgNPs involved in two steps: (i) synthesis of the biogenic silver nanoparticles using the fungal extracts (PF-AgNPs); and, (ii) encapsulation of starch in PF-AgNPs (St-PF-AgNPs). The surface plasmon resonance was found at 420 nm for the PF-AgNPs while it was at 260 and 420 nm for the St-PF-AgNPs. FTIR spectrum demonstrated the capping and encapsulation of the fungal extracts and starch in PF-AgNPs and St-PF-AgNPs. The XRD and TEM-EDS confirmed the crystalline nature, spherical-shaped , and polydispersed- PF-AgNPs and St-PF-AgNPs with strong signals of Ag. The St-PF-AgNPs showed a Z-average size of 115.2 d.nm and zeta potential of -17.8 (mV) as indicated by DLS and zeta potentials. The cytotoxicity results demonstrated higher toxicity of PF-AgNPs than St-PF-AgNPs in HEK293 cells. The antibacterial activity of St-PF-AgNPs were higher than PF-AgNPs in S. aureus. Overall, this work concluded that the starch encapsulation significantly increased the antibacterial activity of PF-AgNPs and this opens a new avenue for the treatment of bacterial infections through the sustained release of PF-AgNPs to target pathogenic bacterial cells.