Conjugation Strategy Research Articles

End‐Extended Conjugation Strategy to Reduce the Efficiency‐Stability‐Mechanical Robustness Gap in Binary All‐Polymer Solar Cells

AbstractConcurrently achieving high efficiency, mechanical robustness and thermal stability is critical for the commercialization of all‐polymer solar cells (APSCs). However, APSCs usually demonstrate complicated morphology, primarily attributed to the polymer chain entanglement which has a detrimental effect on their fill factors (FF) and morphology stability. To address these concerns, an end‐group extended polymer acceptor, PY‐NFT, was synthesized and studied. The morphology analysis showed a tightly ordered molecular packing mode and a favorable phase separation was formed. The PM6 : PY‐NFT‐based device achieved an exceptional PCE of 19.12 % (certified as 18.45 %), outperforming the control PM6 : PY‐FT devices (17.14 %). This significant improvement highlights the record‐high PCE for binary APSCs. The thermal aging study revealed that the PM6 : PY‐NFT blend exhibited excellent morphological stability, thereby achieving superior device stability, retaining 90 % of initial efficiency after enduring thermal stress (65 °C) for 1500 hours. More importantly, the PM6 : PY‐NFT blend film exhibited outstanding mechanical ductility with a crack onset strain of 24.1 %. Overall, rational chemical structure innovation, especially the conjugation extension strategy to trigger appropriate phase separation and stable morphology, is the key to achieving high efficiency, improved thermal stability and robust mechanical stability of APSCs.

Multi-functional tyrosinase inhibitors derived from kojic acid and hydroquinone-like diphenols for treatment of hyperpigmentation: Synthesis and in vitro biological evaluation.

A series of multi-functional tyrosinase inhibitors derived from kojic acid (KA) and hydroquinone-like diphenols were designed and synthesized using click chemistry. The in vitro enzymatic assay revealed that all compounds containing a free enolic structure showed excellent activity against tyrosinase (IC50 = 0.14-3.7 µM), being significantly more potent than KA. The most active compounds were catechol (6c) and α-naphthol (6i) analogs with 138- and 96-fold higher potency than KA. On the other hand, all free phenolic compounds (6a-c and 6g-j) derived from aromatic diols showed outstanding free radical scavenging activities superior to KA. Certainly, the α-naphthol derivative 6i with IC50 = 10.1 µM was the most active anti-oxidant, being as potent as quercetin. The SAR analysis indicated that the enolic head of the conjugate molecules mainly contributes to the anti-tyrosinase activity, and the free phenolic part of the molecules can offer anti-oxidant potency. The anti-melanogenic assay of the most promising derivative, 6i, against melanoma (B16F10) cells demonstrated that the prototype compound 6i can significantly reduce the melanin content, more effectively than KA. By using a conjugation strategy, we have improved the tyrosinase inhibitory and radical scavenging activity in the multi-functional agents such as 6i over the parent compound KA, being potentially useful in the treatment of hyperpigmentation and other skin disorders.

Advancing Cancer Immunotherapy through Engineering New PD-L1 Degraders: A Comprehensive Study from Small Molecules to PD-L1-Specific Peptide-Drug Conjugates.

Despite the considerable achievements of antibodies targeting PD-1/PD-L1 in cancer immunotherapy, limitations in antitumor immune response and pharmacokinetics hinder their clinical adoption. Small molecules toward PD-L1 degradation signifies an innovative avenue to modulate PD-1/PD-L1 axis. Herein, we unveil a comprehensive engineering involving the development of new PD-L1 degraders based on the berberine (BBR) and palmatine (PMT) bioactive frameworks and explore their translational potential for cancer immunotherapy using a peptide-drug conjugate strategy. Chemical modifications at the O-9 position of PMT dramatically enhance the PD-L1 degradation capacity. Further conjugation of PMT degraders with an anti-PD-L1 peptide featuring disulfide linkers enables efficient GSH-specific prodrug activation, yielding synergistic immunotherapeutic benefits through both external PD-L1 blockade and internal PD-L1 degradation mechanisms. This work elucidates the compelling charm of the discovery and application of PD-L1 degraders, offering solutions to the challenges in advancing cancer immunotherapy in widespread clinics.

Nondestructively Assemble Cell Membrane-Coated Nanoparticles by Host-Guest Interactions for Efficient Capture of Bioactive Compounds.

Cell membrane-coated nanoparticles (CNPs) have emerged as an attractive nanomedical tool. The basic premise is that the surface properties of natural cells can be integrated with the physical and chemical properties of nanoparticles by coating them with cell membranes. However, the degree of preservation of membrane proteins on nanoparticles, a key indicator related to the biomedical function of these biomimetic systems, is largely affected by the coating process. Herein, we report a supramolecular cell membrane conjugation strategy mediated by host-guest interactions to assemble CNPs without compromising protein activities. β-cyclodextrin (β-CD) was rapidly and stably inserted into the cell membrane by a lipid anchor without affecting the function of membrane proteins, thus attaching host-guest sites to the membrane surface. By harnessing the excellent binding affinity between β-CD attached to the membrane surface and adamantane, a supramolecular cell membrane-magnetic nanoparticle conjugate (CDM@AMNPs) was synthesized. Thanks to the nondestructive assembly of this strategy, CDM@AMNPs were endowed with a greater number of active binding sites, exhibiting efficient adsorption performance. This supramolecular conjugation strategy mediated by nonreceptor site-based host-guest interactions proposes a scalable and cell-friendly strategy for the development of highly efficient CNPs.

Conjugation of Multiple Proteins Onto the Surface of PLGA/Lipid Hybrid Nanoparticles.

Nanoparticles are increasingly being used in the development of vaccines for disease prevention or treatment. Recent research has demonstrated that conjugating a protein onto the surface of nanoparticles can significantly increase its immunogenicity. Considering various pathogens that threaten human health, multivalent vaccines are often desirable. Up to now, nanoparticle-based vaccines are mostly limited to one protein per nanoparticle. No research has been conducted to explore the possibility of conjugating more than one protein onto the surface of a nanoparticle. Here we developed a specific conjugation strategy to conjugate multiple proteins to the PLGA/lipid hybrid nanoparticle surface. The maleimide-thiol Michael addition, Aizde-DBCO (Dibenzocyclooctyne), and TCO (trans-cycloctene)-Tetrazine click chemistry were employed to conjugate three different proteins, subunit keyhole limpet hemocyanin (sKLH), Ovalbumin (OVA), and cross-reactive material 197 (CRM197), to the surface of PLGA/lipid hybrid nanoparticles (hNPs). The successful results of this study pave the way for developing multivalent vaccines against different pathogens.

End-Extended Conjugation Strategy to Reduce the Efficiency-Stability-Mechanical Robustness Gap in Binary All-Polymer Solar Cells.

Concurrently achieving high efficiency, mechanical robustness and thermal stability is critical for the commercialization of all-polymer solar cells (APSCs). However, APSCs usually demonstrate complicated morphology, primarily attributed to the polymer chain entanglement which has a detrimental effect on their fill factors (FF) and morphology stability. To address these concerns, an end-group extended polymer acceptor, PY-NFT, was synthesized and studied. The morphology analysis showed a tightly ordered molecular packing mode and a favorable phase separation was formed. The PM6 : PY-NFT-based device achieved an exceptional PCE of 19.12 % (certified as 18.45 %), outperforming the control PM6 : PY-FT devices (17.14 %). This significant improvement highlights the record-high PCE for binary APSCs. The thermal aging study revealed that the PM6 : PY-NFT blend exhibited excellent morphological stability, thereby achieving superior device stability, retaining 90 % of initial efficiency after enduring thermal stress (65 °C) for 1500 hours. More importantly, the PM6 : PY-NFT blend film exhibited outstanding mechanical ductility with a crack onset strain of 24.1 %. Overall, rational chemical structure innovation, especially the conjugation extension strategy to trigger appropriate phase separation and stable morphology, is the key to achieving high efficiency, improved thermal stability and robust mechanical stability of APSCs.

Computer-Aided Site-Specific PEGylation of PET Hydrolases for Enhanced PET Degradation.

The enormous accumulation of poly(ethylene terephthalate) (PET) waste has posed a serious threat to the environment and human health, and biodegradation with PET hydrolase (PETase) can be a possible solution. Herein, we propose site-specifically modifying PETase with amphiphilic polymers to improve the enzyme performance at ambient temperature. For this purpose, we devise a computer-aided strategy to prioritize the conjugation site, and polyethylene glycol (PEG) preparations of 0.55 to 10 kDa are site-specifically conjugated to PETase. The most active conjugate PETase-PEG 5k (PETase-5K) shows an increase of melting temperature (3.88 °C) and significantly improves PET degradation performance (3.5- and 3.1-fold increases at 30 and 40 °C, respectively). Experimental investigation and molecular dynamics simulations reveal that the site-specific PEGylation increases the hydrophobic solvent-accessible surface area and the binding capability to the PET surface, thickens the hydration layer, increases the intramolecular hydrogen bonding, reduces the interactions between water and the conjugated enzyme surface, and rigidifies the enzyme structure via hydrogen bonding and hydrophobic interactions between the polymer and the enzyme, thus leading to improved enzymatic performance of PETase-5K. We further validate the versatility of the site-specific PEGylation in one of the most evolved variants of PETase, FAST-PETase, by 1.8-fold improvement in PET degradation at 30 °C. The presented computer-aided site-specific conjugation strategy has opened a new avenue to enhancing PETase performance at ambient temperature, and the contribution of PEGylation to PETase unraveled in this work laid a foundation for the rational engineering of PET hydrolases.

Impact of site-specific conjugation strategies on the pharmacokinetics of antibody conjugated radiotherapeutics

Antibody radionuclide conjugates are an emerging modality for targeted imaging and potent therapy of disseminated disease. Coupling of radionuclides to monoclonal antibodies (mAbs) is typically achieved by applying non-site-specific labelling techniques. With the ambition of reducing variability, increasing labelling efficacy and stability, several site-specific conjugation strategies have been developed in recent years for toxin- and fluorophore-mAb conjugates. In this study, we studied two site-specific labelling strategies for the conjugation of the macrocyclic chelating agent, DOTA, to the anti-Leucine Rich Repeat Containing 15 (LRRC15) mAb DUNP19. Specifically, one approach utilized a DOTA-bearing peptide (FcIII) with a strong affinity for the fragment crystallizable (Fc) domain of the human IgG1 of DUNP19 (DUNP19LF-FcIII-DOTASS), while the other leveraged a chemo-enzymatic technique to substitute the N-linked bi-antennary oligosaccharides in the human IgG1 Fc domain with DOTA (DUNP19LF-gly-DOTASS). To assess if these methods impact the antibody's binding properties and targeting efficacy, comparative in vitro and in vivo studies of the generated DUNP19-conjugates were performed. While the LRRC15 binding of both radioimmunoconjugates remained intact, the conjugation methods had different impacts on their abilities to interact with FcRn and FcγRs. In vitro assessments of DUNP19LF-FcIII-DOTASS and DUNP19LF-gly-DOTASS demonstrated markedly decreased affinity for FcRn and FcγRIIIa (CD16), respectively. DUNP19LF-FcIII-DOTASS demonstrated increased blood and tissue kinetics in vivo, confirming loss of FcRn binding. While the ablated FcγR interaction of DUNP19LF-gly-DOTASS had no immediate impact on in vivo biodistribution, reduced immunotherapeutic effect can be expected in future studies as a result of reduced NK-cells interaction. In conclusion, our findings underscore the necessity for meticulous consideration and evaluation of mAb labelling strategies, extending beyond mere conjugation efficiency and radiolabeling yields. Notably, site-specific labelling methods were found to significantly influence the immunological impact of Fc interactions. Therefore, it is of paramount importance to consider the intended diagnostic or therapeutic application of the construct and to adopt conjugation strategies that ensure the preservation of critical pharmacological properties and functionality of the antibody in use.

Aqueous compatible post-synthetic on-column conjugation of nucleic acids using amino-modifiers.

Nucleic acid conjugation methodologies involves linking the nucleic acid sequence to other (bio)molecules covalently. This typically allows for nucleic acid property enhancement whether it be for therapeutic purposes, biosensing, etc. Here, we report a streamlined aqueous compatible on-column conjugation methodology using nucleic acids containing a site-specific amino-modifier. Both monophosphates and carboxylates were amenable to the conjugation strategy, allowing for the introduction of a variety of useful handles including azide, aryl, and hydrophobic groups in DNA. We find that an on-column approach is superior to post-synthetic template-directed synthesis, mainly with respect to product purification and recovery.

Gene Editing with Artificial DNA Scissors.

Artificial metallo-nucleases (AMNs) are small molecule DNA cleavage agents, also known as DNA molecular scissors, and represent an important class of chemotherapeutic with high clinical potential. This review provides a primary level of exploration on the concepts key to this area including an introduction to DNA structure, function, recognition, along with damage and repair mechanisms. Building on this foundation, we describe hybrid molecules where AMNs are covalently attached to directing groups that provide molecular scissors with enhanced or sequence specific DNA damaging capabilities. As this research field continues to evolve, understanding the applications of AMNs along with synthetic conjugation strategies can provide the basis for future innovations, particularly for designing new artificial gene editing systems.

Cationic Lipid Modification of Nuclear Hormone Receptor-Ligands: A Strategy for Developing a New Class of Targeted Anticancer Therapeutics

Ubiquitous expression patterns of nuclear hormone and their receptors (NHRs) have their own roles in performing essential functions in controlling hormone responsive element-promoted gene transcription. In diseased states such as cancer, NHRs play crucial roles and hence targeting these receptors are essential as it gives us a window of opportunity for developing targeted anticancer therapeutics. In comparison to traditional chemotherapy drugs, targeted therapeutic drugs are hypothetically advantageous in terms of efficacy and safety and hence the idea of developing such targeted drugs are inclined to become a mainstream cancer treatment option. This review selectively compiles data regarding NHR-targeting, while majorly focusing on cancer treatment using anticancer small molecules and/or nanotherapeutics targeting estrogen receptor, progesterone receptor, glucocorticoid receptor, and vitamin D receptor. In this study, we selectively emphasized on estrogen receptor. Herein, we mainly highlight the strategy of lipid-modification to convert respective receptor ligands into NHR-targeted anticancer molecules as well as nanotherapeutics. We focused on the strategy of chemical conjugation of those ligands with twin-aliphatic carbon chain-based cationic lipids. The strategy successfully led to the development of a new class of anticancer therapeutics. These are either small-molecule anticancer agents or selfaggregating nanotherapeutics. In spite of great anticancer output, the concept of NHR-targeted anti-cancer therapy still needs to overcome further hurdles before those are projected for clinical settings.

Sustainable Chemical Modification of Natural Polysaccharides: Mechanochemical, Solvent-Free Conjugation of Pectins and Hyaluronic Acid Promoted by Microwave Radiations.

The modern chemistry has the main focus of saving resources and developing synthetic strategies characterized by intrinsic efficiency, ease and safety in operation, short reaction time, reduced energy, and waste. Natural polysaccharides are largely distributed in plant/animal cells; in other words, they are often provided by renewable sources. This characteristic makes them suitable compounds to be investigated for their employment as biodegradable material. In addition, natural polysaccharides have been proven to have a wide range of applications, and this prompted researchers to investigate their chemical modifications in order to modulate their properties. Herein we discuss the development of conjugation strategies of some polysaccharides with natural substrates and the effects of the structural modification on their bioactivities. Finally, this work intends to provide suggestions and perspectives on the development of safe and sustainable synthetic processes on polysaccharides.

Adipose-derived stem cell-based anti-inflammatory paracrine factor regulation for the treatment of inflammatory bowel disease

Stem cell-based therapies offer promising avenues for treating inflammatory diseases owing to their immunomodulatory properties. However, challenges persist regarding their survival and efficacy in inflamed tissues. Our study introduces a novel approach by engineering adipose-derived stem cells (ADSCs) to enhance their viability in inflammatory environments and boost the secretion of paracrine factors for treating inflammatory bowel disease (IBD). An arginine-glycine-aspartate peptide-poly (ethylene glycol)-chlorin e6 conjugate (RPC) was synthesized and coupled with ADSCs, resulting in RPC-labeled ADSCs (ARPC). This conjugation strategy employed RGD-integrin interaction to shield stem cells and allowed visualization and tracking using chlorin e6. The engineered ARPC demonstrated enhanced viability and secretion of paracrine factors upon light irradiation, regulating the inflammatory microenvironment. RNA-sequencing analysis unveiled pathways favoring angiogenesis, DNA repair, and exosome secretion in ARPC(+) while downregulating inflammatory pathways. In in vivo models of acute and chronic IBD, ARPC(+) treatment led to reduced inflammation, preserved colon structure, and increased populations of regulatory T cells, highlighting its therapeutic potential. ARPC(+) selectively homed to inflammatory sites, demonstrating its targeted effect. Overall, ARPC(+) exhibits promise as an effective and safe therapeutic strategy for managing inflammatory diseases like IBD by modulating immune responses and creating an anti-inflammatory microenvironment.

Antibody Drug Conjugates for Cancer Therapy: From Metallodrugs to Nature-Inspired Payloads.

This review highlights significant advancements in antibody-drug conjugates (ADCs) equipped with metal-based and nature-inspired payloads, focusing on synthetic strategies for antibody conjugation. Traditional methods such us maleimide and succinimide conjugation and classical condensation reactions are prevalent for metallodrugs and natural compounds. However, emerging non-conventional strategies such as photoconjugation are gaining traction due to their milder conditions and, in an aspect which minimizes side reactions, selective formation of ADC. The review also summarizes the therapeutic and diagnostic properties of these ADCs, highlighting their enhanced selectivity and reduced side effects in cancer treatment compared to non-conjugated payloads. ADCs combine the specificity of monoclonal antibodies with the cytotoxicity of chemotherapy drugs, offering a targeted approach to the elimination of cancer cells while sparing healthy tissues. This targeted mechanism has demonstrated impressive clinical efficacy in various malignancies. Key future advancements include improved linker technology for enhanced stability and controlled release of cytotoxic agents, incorporation of novel, more potent, cytotoxic agents, and the identification of new cancer-specific antigens through genomic and proteomic technologies. ADCs are also expected to play a crucial role in combination therapies with immune checkpoint inhibitors, CAR-T cells, and small molecule inhibitors, leading to more durable and potentially curative outcomes. Ongoing research and clinical trials are expanding their capabilities, paving the way for more effective, safer, and personalized treatments, positioning ADCs as a cornerstone of modern medicine and offering new hope to patients.

Design and synthesis of TH19P01-Camptothecin based hybrid peptides inducing effective anticancer responses on sortilin positive cancer cells

Recently, the sortilin receptor (SORT1) was found to be preferentially over-expressed on the surface of many cancer cells, which makes SORT1 a novel anticancer target. The SORT1 binding proprietary peptide TH19P01 could achieve the SORT1-mediated cancer cell binding and subsequent internalization. Inspired by the peptide-drug conjugate (PDC) strategy, the TH19P01-camptothecin (CPT) conjugates were designed, efficiently synthesized, and evaluated for their anticancer potential in this study. The water solubility, in vitro anticancer activity, time-kill kinetics, cellular uptake, anti-migration activity, and hemolysis effects were systematically estimated. Besides, in order to monitor the release of CPT from conjugates in real-time, the CPT/Dnp-based “turn on” hybrid peptide was designed, which indicted that CPT could be sustainably released from the hybrid peptide in both human serum and cancer cellular environments. Strikingly, compared with free CPT, the water solubility, cellular uptake, and selectivity towards cancer cells of hybrid peptide LYJ-2 have all been significantly enhanced. Moreover, unlike free CPT or TH19P01, LYJ-2 exhibited selective anti-proliferative and anti-migration effects against SORT1-positive MDA-MB-231 cells. Collectively, this study not only established efficient strategies to improve the solubility and anticancer potential of chemotherapeutic agent CPT, but also provided important references for the future development of TH19P01 based PDCs targeting SORT1.

One-Pot Strategy for Conjugation of Amine-Covered Iron Oxide Nanoparticles with Carbohydrates: A Sustainable Alternative

One-Pot Strategy for Conjugation of Amine-Covered Iron Oxide Nanoparticles with Carbohydrates: A Sustainable Alternative

Advancing Nitrile-Aminothiol Strategy for Dual and Sequential Bioconjugation.

Nitrile-aminothiol conjugation (NATC) stands out as a promising biocompatible ligation technique due to its high chemo-selectivity. Herein we investigated the reactivity and substrate scope of NAT conjugation chemistry, thus developing a novel pH dependent orthogonal NATC as a valuable tool for chemical biology. The study of reaction kinetics elucidated that the combination of heteroaromatic nitrile and aminothiol groups led to the formation of an optimal bioorthogonal pairing, which is pH dependent. This pairing system was effectively utilized for sequential and dual conjugation. Subsequently, these rapid (≈1 h) and high yield (>90 %) conjugation strategies were successfully applied to a broad range of complex biomolecules, including oligonucleotides, chelates, small molecules and peptides. The effectiveness of this conjugation chemistry was demonstrated by synthesizing a fluorescently labelled antimicrobial peptide-oligonucleotide complex as a dual conjugate to imaging in live cells. This first-of-its-kind sequential NATC approach unveils unprecedented opportunities in modern chemical biology, showcasing exceptional adaptability in rapidly creating structurally complex bioconjugates. Furthermore, the results highlight its potential for versatile applications across fundamental and translational biomedical research.

Control of Solid-Supported Intra- vs Interstrand Stille Coupling Reactions for Synthesis of DNA-Oligophenylene Conjugates.

Programmed DNA structures and assemblies are readily accessible, but site-specific functionalization is critical to realize applications in various fields such as nanoelectronics, nanomaterials and biomedicine. Besides pre- and post-DNA synthesis conjugation strategies, on-solid support reactions offer advantages in certain circumstances. We describe on-solid support internucleotide coupling reactions, often considered undesirable, and a workaround strategy to overcome them. Palladium coupling reactions enabled on-solid support intra- and interstrand coupling between single-stranded DNAs (ss-DNAs). Dilution with a capping agent suppressed interstrand coupling, maximizing intrastrand coupling. Alternatively, interstrand coupling actually proved advantageous to provide dimeric organic/DNA conjugates that could be conveniently separated from higher oligomers, and was more favorable with longer terphenyl coupling partners.

Tailor-Made Bioactive Papers by Site-Specific and Orthogonal Covalent Immobilization of Proteins.

A strategy for the bioorthogonal immobilization of proteins onto commercially available filter paper is presented. Recently, a two-step approach has been described that relies on covalent immobilization of a linker molecule to paper, followed by enzyme-mediated conjugation of a protein of interest containing an enzyme-recognition tag. Here, this strategy was expanded by evaluating four different chemical and chemoenzymatic reactions and investigating paper loading efficiency and orthogonality. Enhanced green fluorescent protein (EGFP) was used as a model protein to allow quantification of protein loading via fluorescence imaging. Two approaches were identified that showed significantly increased loading efficiencies compared with the previously applied conjugation strategy. Additionally, all four methods were proven orthogonal to each other, allowing simultaneous immobilization of a mixture of proteins to a premodified assembly of two paper sheets.

Dual-reactive single-chain polymer nanoparticles for orthogonal functionalization through active ester and click chemistry

Glucose has been extensively studied as a targeting ligand on nanoparticles for biomedical nanoparticles. A promising nanocarrier platform are single-chain polymer nanoparticles (SCNPs). SCNPs are well-defined 5–20 nm semi-flexible nano-objects, formed by intramolecularly crosslinked linear polymers. Functionality can be incorporated by introducing labile pentafluorophenyl (PFP) esters in the polymer backbone, which can be readily substituted by functional amine-ligands. However, not all ligands are compatible with PFP-chemistry, requiring different ligation strategies for increasing versatility of surface functionalization. Here, we combine active PFP-ester chemistry with copper(I)-catalyzed azide alkyne cycloaddition (CuAAC) click chemistry to yield dual-reactive SCNPs. First, the SCNPs are functionalized with increasing amounts of 1-amino-3-butyne groups through PFP-chemistry, leading to a range of butyne-SCNPs with increasing terminal alkyne-density. Subsequently, 3-azido-propylglucose is conjugated through the glucose C1- or C6-position by CuAAC click chemistry, yielding two sets of glyco-SCNPs. Cellular uptake is evaluated in HeLa cancer cells, revealing increased uptake upon higher glucose-surface density, with no apparent positional dependance. The general conjugation strategy proposed here can be readily extended to incorporate a wide variety of functional molecules to create vast libraries of multifunctional SCNPs.