Sensing and Microbiological Activity of a New Blue Fluorescence Polyamidoamine Dendrimer Modified with 1,8-Naphthalimide Units.

A novel second-generation blue fluorescent polyamidoamine dendrimer peripherally modified with sixteen 4-N,N-dimethylaninoethyloxy-1,8-naphthalimide units was synthesized. Its basic photophysical characteristics were investigated in organic solvents of different polarity. It was found that in these solvents, the dendrimer is colorless and emitted blue fluorescence with different intensities depending on their polarity. The effect of the pH of the medium on the fluorescence intensity was investigated and it was found that in the acidic medium, the fluorescence is intense and is quenched in the alkaline medium. The ability of the dendrimer to detect metal ions (Pb2+, Zn2+, Mg2+, Sn2+, Ba2+, Ni2+, Sn2+, Mn2+, Co2+, Fe3+, and Al3+) was also investigated, and it was found that in the presence of Fe3+, the fluorescent intensity was amplified more than 66 times. The antimicrobial activity of the new compound has been tested in vitro against Gram-positive B. cereus and Gram-negative P. aeruginosa. The tests were performed in the dark and after irradiation with visible light. The antimicrobial activity of the compound enhanced after light irradiation and B. cereus was found slightly more sensitive than P. aeruginosa. The increase in antimicrobial activity after light irradiation is due to the generation of singlet oxygen particles, which attack bacterial cell membranes.

Self-Assembled Nanoparticles from the Amphiphilic Prodrug of Resiquimod for Improved Cancer Immunotherapy.

Tumor-associated macrophages (TAMs) usually adopt a tumor-promoting M2-like phenotype, which largely impedes the immune response and therapeutic efficacy of solid tumors. Repolarizing TAMs from M2 to the antitumor M1 phenotype is crucial for reshaping the tumor immunosuppressive microenvironment (TIME). Herein, we developed self-assembled nanoparticles from the polymeric prodrug of resiquimod (R848) to reprogram the TIME for robust cancer immunotherapy. The polymeric prodrug was constructed by conjugating the R848 derivative to terminal amino groups of the linear dendritic polymer composed of linear poly(ethylene glycol) and lysine dendrimer. The amphiphilic prodrug self-assembled into nanoparticles (PLRS) of around 35 nm with a spherical morphology. PLRS nanoparticles could be internalized by antigen-presenting cells (APCs) in vitro and thus efficiently repolarized macrophages from M2 to M1 and facilitated the maturation of APCs. In addition, PLRS significantly inhibited tumor growth in the 4T1 orthotopic breast cancer model with much lower systemic side effects. Mechanistic studies suggested that PLRS significantly stimulated the TIME by repolarizing TAMs into the M1 phenotype and increased the infiltration of cytotoxic T cells into the tumor. This study provides an effective polymeric prodrug-based strategy to improve the therapeutic efficacy of R848 in cancer immunotherapy.

Proton Sponge Nanocomposites for Synergistic Tumor Elimination via Autophagy Inhibition-Promoted Cell Apoptosis and Macrophage Repolarization-Enhanced Immune Response.

Cytoprotective autophagy and an immunosuppressive tumor microenvironment (TME) are two positive promoters for tumor proliferation and metastasis that severely hinder therapeutic efficacy. Inhibiting autophagy and reconstructing TME toward macrophage activation simultaneously are of great promise for effective tumor elimination, yet are still a huge challenge. Herein, a kind of dendrimer-based proton sponge nanocomposites was designed and constructed for tumor chemo/chemodynamic/immunotherapy through autophagy inhibition-promoted cell apoptosis and macrophage repolarization-enhanced immune response. These obtained nanocomposites contain a proton sponge G5AcP dendrimer, a Fenton-like agent Cu(II), and chemical drug doxorubicin (DOX). When accumulated in tumor regions, G5AcP can act as an immunomodulator to realize deacidification-promoted macrophage repolarization toward antitumoral type, which then secretes inflammatory cytokines to activate T cells. They also regulate intracellular lysosomal pH to inhibit cytoprotective autophagy. The released Cu(II) and DOX can induce aggravated damage through a Fenton-like reaction and chemotherapeutic effect in this autophagy-inhibition condition. Tumor-associated antigens are released from these dying tumor cells to promote the maturity of dendritic cells, further activating T cells. Effective tumor elimination can be achieved by this dendrimer-based therapeutic strategy, providing significant guidance for the design of a promising antitumor nanomedicine.

Peptide Dendrimer-Based Antibacterial Agents: Synthesis and Applications.

Pathogenic bacteria cause the deaths of millions of people every year. With the development of antibiotics, hundreds and thousands of people's lives have been saved. Nevertheless, bacteria can develop resistance to antibiotics, rendering them insensitive to antibiotics over time. Peptides containing specific amino acids can be used as antibacterial agents; however, they can be easily degraded by proteases in vivo. To address these issues, branched peptide dendrimers are now being considered as good antibacterial agents due to their high efficacy, resistance to protease degradation, and low cytotoxicity. The ease with which peptide dendrimers can be synthesized and modified makes them accessible for use in various biological and nonbiological fields. That is, peptide dendrimers hold a promising future as antibacterial agents with prolonged efficacy without bacterial resistance development. Their in vivo stability and multivalence allow them to effectively target multi-drug-resistant strains and prevent biofilm formation. Thus, it is interesting to have an overview of the development and applications of peptide dendrimers in antibacterial research, including the possibility of employing machine learning approaches for the design of AMPs and dendrimers. This review summarizes the synthesis and applications of peptide dendrimers as antibacterial agents. The challenges and perspectives of using peptide dendrimers as the antibacterial agents are also discussed.

Molecular mechanism of action of imidazolium carbosilane dendrimers on the outer bacterial membrane - From membrane damage to permeability to antimicrobial endolysin.

The outer bacterial membrane of drug-resistant bacteria is a significant barrier to many antimicrobials. Therefore, the development of new antibacterials primarily focuses on damaging the outer bacterial membrane of Gram-negative bacteria. Among many membrane-disrupting substances, the most promising are cationic dendritic systems. However, the mode of action may vary among different strains due to variations in the lipid compositions of the membrane. Here, we investigated the interaction of two types of cationic imidazolium carbosilane dendrimers: one with a single cationic group (methyl imidazolium) and the other with the same cationic group but attached to a functional group (a pendant pyridyl moiety), capable of establishing interactions with membranes through H-bonding or ion-dipole electrostatic interactions. We used different models of the outer membrane of Gram-negative bacteria - Escherichia coli, Pseudomonas aeruginosa, and Acinetobacter baumannii. Additionally, we assessed the combined effect of the dendrimers and the antibacterial endolysin on P. aeruginosa. Our results show that the mechanism of action depends on the type of dendrimer and the lipid composition of the membrane. We also demonstrate that the alteration of membrane fluidity and permeability to endolysin by the methyl imidazolium and pyridyl imidazolium dendrimers may play a more significant role in antimicrobial activity compared to membrane damage caused by positively charged dendrimers.

Polycationic phosphorous dendrimer potentiates multiple antibiotics against drug-resistant mycobacterial pathogens.

Mycobacterium tuberculosis (Mtb), causative agent of tuberculosis (TB) and non-tubercular mycobacterial (NTM) pathogens such as Mycobacterium abscessus are one of the most critical concerns worldwide due to increased drug-resistance resulting in increased morbidity and mortality. Therefore, focusing on developing novel therapeutics to minimize the treatment period and reducing the burden of drug-resistant Mtb and NTM infections are an urgent and pressing need. In our previous study, we identified anti-mycobacterial activity of orally bioavailable, non-cytotoxic, polycationic phosphorus dendrimer 2G0 against Mtb. In this study, we report ability of 2G0 to potentiate activity of multiple classes of antibiotics against drug-resistant mycobacterial strains. The observed synergy was confirmed using time-kill kinetics and revealed significantly potent activity of the combinations as compared to individual drugs alone. More importantly, no re-growth was observed in any tested combination. The identified combinations were further confirmed in intra-cellular killing assay as well as murine model of NTM infection, where 2G0 potentiated the activity of all tested antibiotics significantly better than individual drugs. Taken together, this nanoparticle with intrinsic antimycobacterial properties has the potential to represents an alternate drug candidate and/or a novel delivery agent for antibiotics of choice for enhancing the treatment of drug-resistant mycobacterial pathogens.

Prednisone and ibuprofen conjugate Janus dendrimers and their anticancer activity.

Drug release from hyperbranched Janus dendrimer-drug conjugates and their subsequent activity are influenced by the different drugs in each dendron and the linker. To understand these effects, we synthetized new Janus-type dendrimers of first and second generation. One dendron with 2,2-Bis(hydroxymethyl)propionic acid functionalized with ibuprofen and the second dendron was obtained with 3-aminopropanol-amidoamine and prednisone. The dendrimers were obtained by copper(I)-catalyzed Click azide-alkyne cycloaddition for the formation of a triazole as a dendrimeric nucleus of Janus dendrimer conjugates are reported. The influence of ibuprofen, prednisone, and spacer on cancer activity of Janus dendrimers conjugates is reported. The IC50 values of the anticancer activity on cancer cell lines the Janus dendrimer of second generation was higher in comparison to the first generation dendrimer. Similarly, the anticancer activity was higher compared to the dendron conjugates. Also, no cytotoxic effects of dendrons and dendrimers on non-cancerous kidney COS-7 cell line was observed. The interesting anticancer activity of the prepared prednisone-ibuprofen Janus dendrimer conjugates suggest that the dendrimers could be of potential use as new anticancer drug.

Ultra-Galactocation to Sialic Acid on Tumor Cells with A Penta-Functional Dendritic Probe for Enhanced Immune-Killing.

Glycans on tumor cell surface have significant impacts in the immune-killing process. Here an ultra-galactocation to sialic acid (Sia) strategy is designed to hugely introduce galactose (Gal) to Sia and on tumor cells in vivo by using a penta-functional dendritic probe (Den@5F), which efficiently enhances the immune-killing of tumor cells. The Den@5F contains five different kinds of functional groups, including Gal, Cy5, amino, phenylboronic acid (PBA) and 4-(4-(hydroxymethyl)-2-methoxy-5-nitrophenoxy) butanoate (mNB), which can be conveniently prepared through a two-step reaction. After injecting into the tumor-bearing mouse, Den@5F can efficiently block Sia through the specific recognition between PBA and Sia on tumor cells and hugely introduce Gal through the subsequent photo-crosslinking between mNB and amino groups to multiply conjugate excessive Den@5Fs. The comprehensively blocked Sia can prevent the immune escape, and the hugely introduced Gal can promote the immune stimulation of the immune cells, which lead to an efficient enhancement of the immune-killing. The proposed strategy provides a significant and promising tool to promote the clinical immunotherapy of tumor.

Enhanced Immunomodulatory Effects of Thymosin-Alpha-1 in Combination with Polyanionic Carbosilane Dendrimers against HCMV Infection.

Resistance and toxicity associated with current treatments for human cytomegalovirus (HCMV) infection highlight the need for alternatives and immunotherapy has emerged as a promising strategy. This study examined the in vitro immunological effects of co-administration of Thymosin-alpha-1 (Tα1) and polyanionic carbosilane dendrimers (PCDs) on peripheral blood mononuclear cells (PBMCs) during HCMV infection. The biocompatibility of PCDs was assessed via MTT and LDH assays. PBMCs were pre-treated with the co-administered compounds and then exposed to HCMV for 48 h. Morphological alterations in PBMCs were observed using optical microscopy and total dendritic cells (tDCs), myeloid dendritic cells (mDCs), and plasmacytoid dendritic cells (pDCs), along with CD4+/CD8+ T cells and regulatory T cells (Treg), and were characterized using multiparametric flow cytometry. The findings revealed that Tα1 + PCDs treatments increased DC activation and maturation. Furthermore, increased co-receptor expression, intracellular IFNγ production in T cells and elevated Treg functionality and reduced senescence were evident with Tα1 + G2-S24P treatment. Conversely, reduced co-receptor expression, intracellular cytokine production in T cells, lower functionality and higher senescence in Treg were observed with Tα1 + G2S16 treatment. In summary, Tα1 + PCDs treatments demonstrate synergistic effects during early HCMV infection, suggesting their use as an alternative therapeutic for preventing virus infection.

Targeted Extracellular Protein Degradation by Dendronized DNA Chimeras.

Extracellular soluble proteins are key agents in the development of various diseases. However, strategies to remove therapeutically relevant extracellular targets are still scarce. Here, we establish dendronized DNA chimera (DENTAC) as an efficient approach for targeted degradation of the extracellular protein of interest (ePOI). DENTAC consists of a DNA dendron against cell-surface scavenger receptors (SRs), a protein ligand, and a connecting linker, which harnesses SRs as a lysosome-trafficking receptor to mediate the lysosomal degradation of the ePOI. We interrogate and optimize structure-activity relationships of DENTAC. Using neutravidin as a model ePOI, we show that both branch number and DNA length in the DNA dendron are important determinants for efficient lysosomal delivery and degradation of the protein. We demonstrate three branches and 10 nucleotide-length polythymidine as the optimal DNA dendron components to construct DENTAC. We further exemplify the anticancer application of DENTAC by targeting matrix metalloproteinase-9 (MMP-9), where we find linker property as another factor important for DENTAC performance. We reveal that MMP-9-targeting DENTAC effectively restrain cancer cell proliferation, migration, and invasion. This study thus provides a potent strategy to delete extracellular proteins that are commonly difficult to target.

Bioactive Phosphorus Dendrimers as a Universal Protein Delivery System for Enhanced Anti-inflammation Therapy.

Nanocarrier-based cytoplasmic protein delivery offers opportunities to develop protein therapeutics; however, many delivery systems are positively charged, causing severe toxic effects. For enhanced therapeutics, it is also of great importance to design nanocarriers with intrinsic bioactivity that can be integrated with protein drugs due to the limited bioactivity of proteins alone for disease treatment. We report here a protein delivery system based on anionic phosphite-terminated phosphorus dendrimers with intrinsic anti-inflammatory activity. A phosphorus dendrimer termed AK-137 with optimized anti-inflammatory activity was selected to complex proteins through various physical interactions. Model proteins such as bovine serum albumin, ribonuclease A, ovalbumin, and fibronectin (FN) can be transfected into cells to exert their respective functions, including cancer cell apoptosis, dendritic cell maturation, or macrophage immunomodulation. Particularly, the constructed AK-137@FN nanocomplexes display powerful therapeutic effects in acute lung injury and acute gout arthritis models by integrating the anti-inflammatory activity of both the carrier and protein. The developed anionic phosphite-terminated phosphorus dendrimers may be employed as a universal carrier for protein delivery and particularly utilized to deliver proteins and fight different inflammatory diseases with enhanced therapeutic efficacy.

Zwitterionic Injectable Hydrogel-Combined Chemo- and Immunotherapy Medicated by Monomolecular Micelles to Effectively Prevent the Recurrence of Tumor Post Operation.

Surgical resection remains the most common method of tumor treatment; however, the high recurrence and metastasis after surgery need to be solved urgently. Herein, we report an injectable zwitterionic hydrogel based on "thiol-ene" click chemistry containing doxorubicin (DOX) and a macrophage membrane (MM)-coated 1-methyl-tryptophan (1-MT)-loaded polyamide-amine dendrimer (P-DOX/1MT) for preventing the postoperative recurrence of tumors. The results indicated that P-DOX/1MT@MM exhibited enhanced recognition and uptake of the dendrimer by tumor cells and induced the immunogenic cell death. In the mice tumor model, the P-DOX/1MT@MM-Gel exhibited high therapeutic efficiency, which could significantly reduce the recurrence of the tumor, including suppressing tumor growth, promoting dendritic cell maturation, and increasing tumor-infiltrating cytotoxic T lymphocytes. The mechanism analysis revealed that the hydrogel greatly reduces the side effects to normal tissues and significantly improves its therapeutic effect. 1MT in the hydrogel is released more rapidly, improving the tumor suppressor microenvironment and increasing the tumor cell sensitivity to DOX. Then, the DOX in the P-DOX/1MT@MM effectively eliminatedo the residual tumor cells and exerted enhanced toxicity. In conclusion, this novel injectable hydrogel that combines chemotherapy and immunotherapy has the property of sequential drug release and is a promising strategy for preventing the postoperative recurrence of tumors.

Amphiphilic Dendrimer as Potent Antibacterial against Drug-Resistant Bacteria in Mouse Models of Human Infectious Diseases.

Modern medicine continues to struggle against antibiotic-resistant bacterial pathogens. Among the pathogens of critical concerns are the multidrug-resistant (MDR) Pseudomonas aeruginosa, Staphylococcus aureus, and Klebsiella pneumoniae. These pathogens are major causes of nosocomial infections among immunocompromised individuals, involving major organs such as lung, skin, spleen, kidney, liver, and bloodstream. Therefore, novel approaches are direly needed. Recently, we developed an amphiphilic dendrimer DDC18-8A exhibiting high antibacterial and antibiofilm efficacy in vitro. DDC18-8A is composed of a long hydrophobic alkyl chain and a small hydrophilic poly(amidoamine) dendron bearing amine terminals, exerting its antibacterial activity by attaching and inserting itself into bacterial membranes to trigger cell lysis. Here, we examined the pharmacokinetics and in vivo toxicity as well as the antibacterial efficacy of DDC18-8A in mouse models of human infectious diseases. Remarkably, DDC18-8A significantly reduced the bacterial burden in mouse models of acute pneumonia and bacteremia by P. aeruginosa, methicillin-resistant S. aureus (MRSA), and carbapenem-resistant K. pneumoniae and neutropenic soft tissue infection by P. aeruginosa and MRSA. Most importantly, DDC18-8A outperformed pathogen-specific antibiotics against all three pathogens by achieving a similar bacterial clearance at 10-fold lower therapeutic concentrations. In addition, it showed superior stability and biodistribution in vivo, with excellent safety profiles yet without any observable abnormalities in histopathological analysis of major organs, blood serum biochemistry, and hematology. Collectively, we provide strong evidence that DDC18-8A is a promising alternative to the currently prescribed antibiotics in addressing challenges associated with nosocomial infections by MDR pathogens.

Self-assembly of alkylated lysine-dendron oxytocin amphiphiles for enhanced stability and sustained pharmacological activity.

Herein, we designed alkylated lysine-dendron oxytocin amphiphiles (ALOAs) 1G-OTK and 2G-OTK, which were self-assembled into spherical nanoparticles and nanostrips, respectively, and showed superior stability compared to native oxytocin. We found similar trends in the functional activity of ALOAs and native OT for human oxytocin receptor. This work may inspire the development of peptide drugs for clinical applications.

Study of the antimicrobial activity of cationic carbosilane dendrimers against clinical strains of multidrug-resistant bacteria and their biofilms.

Introduction: Antimicrobial Resistance is a serious public health problem, which is aggravated by the ability of the microorganisms to form biofilms. Therefore, new therapeutic strategies need to be found, one of them being the use of cationic dendritic systems (dendrimers and dendrons). Methods: The aim of this study is to analyze the in vitro antimicrobial efficacy of six cationic carbosilane (CBS) dendrimers and one dendron with peripheral ammonium groups against multidrug-resistant bacteria, some of them isolated hospital strains, and their biofilms. For this purpose, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), minimum biofilm inhibitory concentration (MBIC) and minimum eradication biofilm concentration (MBEC) studies were carried out. In addition, the cytotoxicity on Hela cells of those compounds that proved to be the most effective was analyzed. Results: All the tested compounds showed in vitro activity against the planktonic forms of methicillin-resistant Staphylococcus aureus and only the dendrimers BDSQ017, BDAC-001 and BDLS-001 and the dendron BDEF-130 against their biofilms. On the other hand, only the dendrimers BDAC 001, BDLS-001 and BDJS-049 and the dendron BDEF-130 were antibacterial in vitro against the planktonic forms of multidrug-resistant Pseudomonas aeruginosa, but they lacked activity against their preformed biofilms. In addition, the dendrimers BDAC-001, BDLS-001 and BDSQ-017 and the dendron BDEF-130 exhibited a good profile of cytotoxicity in vitro. Discussion: Our study demonstrates the possibility of using the four compounds mentioned above as possible topical antimicrobials against the clinical and reference strains of multidrug-resistant bacteria.

Exploring the Potential of Lapatinib, Fulvestrant, and Paclitaxel Conjugated with Glycidylated PAMAM G4 Dendrimers for Cancer and Parasite Treatment.

Fulvestrant (F), lapatinib (L), and paclitaxel (P) are hydrophobic, anticancer drugs used in the treatment of estrogen receptor (ER) and epidermal growth factor receptor (EGFR)-positive breast cancer. In this study, glycidylated PAMAM G4 dendrimers, substituted with F, L, and/or P and targeting tumor cells, were synthesized and characterized, and their antitumor activity against glioma U-118 MG and non-small cell lung cancer A549 cells was tested comparatively with human non-tumorogenic keratinocytes (HaCaT). All cell lines were ER+ and EGFR+. In addition, the described drugs were tested in the context of antinematode therapy on C. elegans. The results show that the water-soluble conjugates of G4P, G4F, G4L, and G4PFL actively entered the tested cells via endocytosis due to the positive zeta potential (between 13.57-40.29 mV) and the nanoparticle diameter of 99-138 nm. The conjugates of G4P and G4PFL at nanomolar concentrations were the most active, and the least active conjugate was G4F. The tested conjugates inhibited the proliferation of HaCaT and A549 cells; in glioma cells, cytotoxicity was associated mainly with cell damage (mitochondria and membrane transport). The toxicity of the conjugates was proportional to the number of drug residues attached, with the exception of G4L; its action was two- and eight-fold stronger against glioma and keratinocytes, respectively, than the equivalent of lapatinib alone. Unfortunately, non-cancer HaCaT cells were the most sensitive to the tested constructs, which forced a change in the approach to the use of ER and EGFR receptors as a goal in cancer therapy. In vivo studies on C. elegans have shown that all compounds, most notably G4PFL, may be potentially useful in anthelmintic therapy.

Antibacterial Broad-Spectrum Dendritic/Gellan Gum Hybrid Hydrogels with Rapid Shape-Forming and Self-Healing for Wound Healing Application.

Treating wound infections is a difficult task ever since pathogenic bacteria started to develop resistance to common antibiotics. The present study develops hybrid hydrogels based on the formation of a polyelectrolyte complex between the anionic charges of dopamine-functionalized Gellan Gum (GG-DA) and the cationic moieties of the TMP-G2-alanine dendrimer. The hydrogels thus obtained can be doubly crosslinked with CaCl2 , obtaining solid hydrogels. Or, by oxidizing dopamine to GG-DA, possibly causing further interactions such as Schiff Base and Michael addition to take place, hydrogels called injectables can be obtained. The latter have shear-thinning and self-healing properties (efficiency up to 100%). Human dermal fibroblasts (HDF), human epidermal keratinocytes (HaCaT), and mouse monocyte cells (RAW 264.7), after incubation with hydrogels, in most cases show cell viability up to 100%. Hydrogels exhibit adhesive behavior on various substrates, including porcine skin. At the same time, the dendrimer serves to crosslink the hydrogels and endows them with excellent broad-spectrum microbial eradication activity within four hours, evaluated using Staphylococcus aureus 2569 and Escherichia coli 178. Using the same GG-DA/TMP-G2-alanine ratios hybrid hydrogels with tunable properties and potential for wound dressing applications can be produced.

Potential anti-adhesion activity of novel carbosilane zwitterionic dendrimers against eukaryotic and prokaryotic pathogenic microorganisms.

The development of biofilms on different surfaces continues to be a major public health problem. The antimicrobial resistance and the difficulty of finding drugs capable of combating these established biofilms generates the urgent need to find compounds that prevent cells from settling and establishing of these complex communities of microorganisms. Zwitterionic modification of nanomaterials allows the formation of a hydration layer, and this highly hydrophilic surface provides antifouling properties as well as a good biocompatibility by preventing non-specific interactions. Thus, they are appropriate candidates to prevent microbial adhesion to different surfaces and, in consequence, avoid biofilm formation. For this reason, we have incorporated zwitterionic moieties in multivalent systems, as are carbosilane dendrimers. Characterization of these systems was performed using nuclear magnetic resonance and mass spectrometry. It has been analysed if the new molecules have capacity to inhibit the biofilm formation in Candida albicans, Staphylococcus aureus and Pseudomonas aeruginosa. The results showed that they were more effective against S. aureus, observing a biofilm reduction of 81.5% treating with 32 mg/L of G2SiZWsf dendrimer and by 72.5% using 32 mg/L of the G3SiZWsf dendrimer. Finally, the absence of cytotoxicity was verified by haemolysis and cytotoxicity studies in human cells lines.

Synthesis of multivalent sialyllactose-conjugated PAMAM dendrimers: Binding to SARS-CoV-2 spike protein and influenza hemagglutinin.

Severe acute respiratory syndrome-related coronavirus-2 (SARS-CoV-2) and influenza viruses have spread around the world at an unprecedented rate. Despite multiple vaccines, new variants of SARS-CoV-2 and influenza have caused a remarkable level of pathogenesis. The development of effective antiviral drugs to treat SARS-CoV-2 and influenza remains a high priority. Inhibiting viral cell surface attachment represents an early and efficient means to block virus infection. Sialyl glycoconjugates, on the surface of human cell membranes, play an important role as host cell receptors for influenza A virus and 9-O-acetyl-sialylated glycoconjugates are receptors for MERS, HKU1 and bovine coronaviruses. We designed and synthesized multivalent 6'-sialyllactose-counjugated polyamidoamine dendrimers through click chemistry at room temperature concisely. These dendrimer derivatives have good solubility and stability in aqueous solutions. SPR, a real-time analysis quantitative method for of biomolecular interactions, was used to study the binding affinities of our dendrimer derivatives by utilizing only 200 micrograms of each dendrimer. Three SARS-CoV-2 S-protein receptor binding domain (wild type and two Omicron mutants) bound to multivalent 9-O-acetyl-6'-sialyllactose-counjugated and 6'-sialyllactose-counjugated dendrimers bound to a single H3N2 influenza A virus's HA protein (A/Hong Kong/1/1968), the SPR study results suggest their potential anti-viral activities.

Gene Delivery into T-Cells Using Ternary Complexes of DNA, Lipofectamine, and Carboxy-Terminal Phenylalanine-Modified Dendrimers.

T-cells play critical roles in various immune reactions, and genetically engineered T-cells have attracted attention for the treatment of cancer and autoimmune diseases. Previously, it is shown that a polyamidoamine dendrimer of generation 4 (G4), modified with 1,2-cyclohexanedicarboxylic anhydride (CHex) and phenylalanine (Phe) (G4-CHex-Phe), is useful for delivery into T-cells and their subsets. In this study, an efficient non-viral gene delivery system is constructed using this dendrimer. Ternary complexes are prepared using different ratios of plasmid DNA, Lipofectamine, and G4-CHex-Phe. A carboxy-terminal dendrimer lacking Phe (G3.5) is used for comparison. These complexes are characterized using agarose gel electrophoresis, dynamic light scattering, and ζpotential measurements. In Jurkat cells, the ternary complex with G4-CHex-Phe at a P/COOH ratio of 1/5 shows higher transfection activity than other complexes, such as binary and ternary complexes with G3.5, without any significant cytotoxicity. The transfection efficiency of the G4-CHex-Phe ternary complexes decreases considerably in the presence of free G4-CHex-Phe and upon altering the complex preparation method. These results suggest that G4-CHex-Phe promotes the cellular internalization of the complexes, which is useful for gene delivery into T-cells.