Biosens Bioelectron. 2019 Sep 15:141:111477. doi: 10.1016/j.bios.2019.111477. Epub 2019 Jun 25. Novel thiolated-PEG linker molecule for biosensor development on gold surfaces Abstract The surface modifying linker molecules can directly influence the performance and longevity of biosensors. They must allow the attachment of biological recognition layer on the sensor surface, as well as the protection of the surface from fouling effects. Recent advances in this field identified several key factors that can increase the efficiency, stability and the anti-fouling effect of a layer formed by surface modifying linker molecules. Herein, this work presents a simple synthetic procedure, characterization, and application of a novel thiolated-PEG surface modifying molecule (DSPEG2) that could act as a multi-purpose linker for gold surfaces. The analyses of the molecular spatial distribution of DSPEG2 on gold surfaces were performed using time-of-flight secondary ion mass spectrometry (TOF-SIMS) imaging and X-ray photoelectric spectroscopy (XPS). The immobilization of DSPEG2 on gold surfaces was examined using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and surface plasmon resonance (SPR). Our preliminary results demonstrated that DSPEG2 is a promising novel linker molecule that can be applied in a wide range of biosensors based on gold surfaces. Keywords: Anti-fouling; Biosensor; Cyclic voltammetry; Electrochemical impedance spectroscopy; Non-specific adsorption; PEG; Surface plasmon resonance; Synthetic linker.

Br J Haematol. 2020 May;189(3):442-451. doi: 10.1111/bjh.16254. Epub 2019 Dec 27. Acute lymphoblastic leukaemia patients treated with PEGasparaginase develop antibodies to PEG and the succinate linker Abstract Polyethylene glycol (PEG) conjugated asparaginase (PEGasparaginase) is essential for treatment of paediatric acute lymphoblastic leukaemia. We developed an assay identifying antibodies against the PEG-moiety, the linker and the drug itself in patients experiencing hypersensitivity reactions to PEGasparaginase. Eighteen patients treated according to the DCOG ALL-11 protocol, with a neutralizing hypersensitivity reaction to PEGasparaginase to the first PEGasparaginase doses in induction (12 patients) or during intensification after interruption of several months (6 patients) were included. ELISA was used to measure antibodies, coating with the succinimidyl succinate linker conjugated to BSA, PEGfilgrastim and Escherichia coli asparaginase, and using hydrolysed PEGasparaginase and mPEG5,000 for competition. Anti-PEG antibodies were detected in all patients (IgG 100%; IgM 67%) of whom 39% had anti-PEG antibodies exclusively. Pre-existing anti-PEG antibodies were also detected in patients who not previously received a PEGylated therapeutic (58% IgG; 21% IgM). Antibodies against the SS-linker were predominantly detected during induction (50% IgG; 42% IgM). Anti-asparaginase antibodies were detected in only 11% during induction but 94% during intensification. In conclusion, anti-PEG and anti-SS-linker antibodies predominantly play a role in the immunogenic response to PEGasparaginase during induction. Thus, switching to native E. coli asparaginase would be an option for adequate asparaginase treatment. Keywords: PEGasparaginase; acute lymphoblastic leukemia; antibodies.

Review Nanomedicine (Lond). 2016 Apr;11(7):851-65. doi: 10.2217/nnm.16.28. Gold nanoparticle surface functionalization: mixed monolayer versus hetero bifunctional peg linker Abstract To create a clinically relevant gold nanoparticle (AuNP) treatment, the surface must be functionalized with multiple ligands such as drugs, antifouling agents and targeting moieties. However, attaching several ligands of differing chemistries and lengths, while ensuring they all retain their biological functionality remains a challenge. This review compares the two most widely employed methods of surface cofunctionalization, namely mixed monolayers and hetero-bifunctional linkers. While there are numerous in vitro studies successfully utilizing both surface arrangements, there is little consensus regarding their relative merits. Animal and preclinical studies have demonstrated the effectiveness of mixed monolayer functionalization and while some promising in vitro results have been reported for PEG linker capped AuNPs, any potential benefits of the approach are not yet fully understood.

Int J Nanomedicine. 2023 Mar 30:18:1615-1630. doi: 10.2147/IJN.S402418. eCollection 2023. Effects of PEG-Linker Chain Length of Folate-Linked Liposomal Formulations on Targeting Ability and Antitumor Activity of Encapsulated Drug Abstract Introduction: Ligand-conjugated liposomes are promising for the treatment of specific receptor-overexpressing cancers. However, previous studies have shown inconsistent results because of the varying properties of the ligand, presence of a polyethylene glycol (PEG) coating on the liposome, length of the linker, and density of the ligand. Methods: Here, we prepared PEGylated liposomes using PEG-linkers of various lengths conjugated with folate and evaluated the effect of the PEG-linker length on the nanoparticle distribution and pharmacological efficacy of the encapsulated drug both in vitro and in vivo. Results: When folate was conjugated to the liposome surface, the cellular uptake efficiency in folate receptor overexpressed KB cells dramatically increased compared to that of the normal liposome. However, when comparing the effect of the PEG-linker length in vitro, no significant difference between the formulations was observed. In contrast, the level of tumor accumulation of particles in vivo significantly increased when the length of the PEG-linker was increased. The tumor size was reduced by >40% in the Dox/FL-10K-treated group compared to that in the Dox/FL-2K- or 5K-treated groups. Discussion: Our study suggests that as the length of PEG-linker increases, the tumor-targeting ability can be enhanced under in vivo conditions, which can lead to an increase in the antitumor activity of the encapsulated drug. Keywords: PEG-linker length; PEGylated liposome; folate receptor; ligand-conjugated liposome.

At the forefront of modern drug development, polyethylene glycol (PEG) derivatives play a crucial role. They act like an "invisibility cloak" for drug molecules, significantly enhancing therapeutic efficacy and safety, representing a revolutionary technology in the field of pharmaceutical chemistry.     1. What are Polyethylene Glycol (PEG) Derivatives?   Polyethylene Glycol (PEG) is a linear, water-soluble, highly biocompatible polymer synthesized from the polymerization of ethylene oxide. It is non-toxic, non-immunogenic, and has been approved by the U.S. FDA as a safe chemical substance for oral, injectable, and topical use.   PEG derivatives specifically refer to those PEG molecules that have been chemically modified to carry specific reactive functional groups (e.g., amino, carboxyl, maleimide, N-hydroxysuccinimide ester) at one or both ends of their molecular chains. These functional groups act like "grappling hands," enabling covalent binding to specific groups (e.g., amino, thiol groups) on proteins, peptides, antibodies, small molecule drugs, and even nanoparticles (like liposomes).   This process is known as "PEGylation". Through PEGylation, one or more PEG chains are attached to the drug molecule, fundamentally altering its physicochemical properties and in vivo behavior.     2. Applications in Modern Medicine   As a mature drug delivery and improvement strategy, PEGylation technology is extremely widespread in modern medicine, primarily serving the following purposes:   Increase Drug Solubility: Many hydrophobic drugs have poor solubility in water, making them difficult to formulate into injectable solutions. Attaching hydrophilic PEG chains can significantly enhance a drug's aqueous solubility.   Prolong Half-life, Reduce Dosing Frequency: ①Increase Molecular Size: The addition of PEG chains significantly increases the drug's molecular weight, making it less likely to be filtered through the glomeruli, thereby slowing renal clearance. ②Reduce Immune Recognition: The PEG chain acts like a protective shield, enveloping the drug surface, masking its antigenic epitopes, and reducing the chance of recognition and clearance by the immune system. ③Hinder Enzymatic Degradation: This same shielding effect also reduces the rate at which the drug is degraded by hydrolytic enzymes like proteases.   Reduce Immunogenicity and Toxicity:For protein-based drugs (e.g., enzymes, cytokines), PEGylation can mask their heterologous nature, reducing the likelihood of the body producing antibodies, thus minimizing allergic reactions. It can also modify toxic functional groups of certain drugs, improving their safety profile (therapeutic window).   Enhance Targeting (Passive Targeting): By prolonging the drug's circulation time in the bloodstream via PEGylation, the drug is more likely to accumulate in tissues with leaky vasculature, such as tumors or inflamed sites, through the Enhanced P...

Review Zhejiang Da Xue Xue Bao Yi Xue Ban. 2022 Apr 25;51(2):185-191. doi: 10.3724/zdxbyxb-2022-0047. Research advance in lipid nanoparticle-mRNA delivery system and its application in CAR-T cell therapy Abstract Chimeric antigen receptor (CAR) T cell therapy has shown significant efficacy for hematological malignancies, however, it needs to be further optimized. Recently, the lipid nanoparticle (LNP)-mRNA delivery system as a nonviral gene transfer vector has gained rapid progress in CAR-T cell therapy. The claudin-6 (CLDN6) mRNA is delivered to antigen presenting cells (APCs) through LNP system, thereby enhancing the function of CLDN6 CAR-T cells for the clearance of solid tumor cells. For treatment of acute cardiac injury, the fibroblast activation protein (FAP) CAR mRNA can be delivered to T cells through LNP system for the in vivo production of FAP CAR-T cells, thereby blocking the process of myocardial fibrosis. The LNP-mRNA delivery system has advantages including having no integration in host genome, inexpensiveness, low toxicity and modifiability; on the other hand, it has certain disadvantages such as limited cell persistence caused by transient protein expression and limitations in preparation techniques. This article reviews the research advance in LNP-mRNA in vivo delivery system and its application in CAR-T cell therapy. Keywords: Chimeric antigen receptor T cell; Gene transfer vector; Lipid nanoparticle; Messenger RNA; Review; delivery system. For more product information, please contact us at: US Tel: 1-844-782-5734 US Tel: 1-844-QUAL-PEG CHN Tel: 400-918-9898 Email: sales@sinopeg.com

J Control Release. 2024 Sep:373:952-961. doi: 10.1016/j.jconrel.2024.07.046. Epub 2024 Aug 8. A perspective on bleb and empty LNP structures Abstract Although lipid nanoparticles (LNPs) have been FDA-approved for mRNA delivery, there is still much to learn about these fascinating multi-component delivery systems. Here, I discuss the presence of "bleb" structures on LNPs and the co-existence of mRNA-empty LNPs in LNP-mRNA-based formulations. Specifically, I discuss key articles on these structural and compositional heterogeneities, whether these features present negative or positive LNP attributes, and how to deal with them in research and quality control settings. Additionally, I present current approaches and propose novel strategies on how to study and quantify bleb and empty LNP structures. With the conflicting views on these features in the literature and limited systematic studies on their impact on safety and efficacy, I hope this Perspective will support current and bring forward new thinking about these matters. I anticipate that novel studies and insights could emerge from these lines of thinking, which could potentially enhance the development of safe and efficient LNP-based drug products that will either embrace, leverage, or mitigate the presence of blebs and empty LNPs. Keywords: Bleb; Empty; LNP; Lipid nanoparticles; Quantifcation; Structures. For more product information, please contact us at: US Tel: 1-844-782-5734 US Tel: 1-844-QUAL-PEG CHN Tel: 400-918-9898 Email: sales@sinopeg.com

J Control Release. 2021 Jul 10:335:237-246. doi: 10.1016/j.jconrel.2021.05.021. Epub 2021 May 18. Impact of lipid nanoparticle size on mRNA vaccine immunogenicity Abstract Lipid nanoparticles (LNP) are effective delivery vehicles for messenger RNA (mRNA) and have shown promise for vaccine applications. Yet there are no published reports detailing how LNP biophysical properties can impact vaccine performance. In our hands, a retrospective analysis of mRNA LNP vaccine in vivo studies revealed a relationship between LNP particle size and immunogenicity in mice using LNPs of various compositions. To further investigate this, we designed a series of studies to systematically change LNP particle size without altering lipid composition and evaluated biophysical properties and immunogenicity of the resulting LNPs. While small diameter LNPs were substantially less immunogenic in mice, all particle sizes tested yielded a robust immune response in non-human primates (NHP). Keywords: Lipid; Nanoparticle; Size; Vaccine; mRNA. For more product information, please contact us at: US Tel: 1-844-782-5734 US Tel: 1-844-QUAL-PEG CHN Tel: 400-918-9898 Email: sales@sinopeg.com