We here describe a synthetic strategy to efficiently prepare polymer-functionalized lanthanide-doped nanoparticles (LNPs) via "one-pot" ω-chain end aminolysis/thiolate-grafting of reversible addition-fragmentation chain-transfer (RAFT) polymers onto the surface of LNPs. Two representative polymers, poly(diethylene glycol methyl ether methacrylate) (PDEGMA) and poly[poly(ethylene glycol) methyl ether methacrylate] (PPEGMA), are prepared via RAFT, and their end-group functionalization onto the surface of NaYF4:Yb, Tm-based LNPs is demonstrated via an in situ tandem process. The achieved nanohybrids exhibit enhanced water-dispersibility and cellular compatibility. Structural integrity and grafting confirmation of the constructed nanoconjugates are successfully made by combined studies of NMR, Fourier transform infrared (FTIR), fluorescence spectroscopy, and X-ray diffraction (XRD). The size and morphology of the hybrid nanomaterials in solution are determined by dynamic light scattering (DLS) spectroscopy and high-resolution transmission electron microscopy (HR-TEM), and the photothermal activity is probed for their potential theranostic applications.

Enzymes are well-known biocatalysts for natural metabolic reactions and synthetic organic reactions. For many decades, enzymatic catalysis has been successfully implemented for the in vitro synthesis of polymers and their modifications; however, in recent years, we have witnessed unprecedented attention towards leveraging reversible addition-fragmentation chain transfer (RAFT) polymerization-based versatile techniques. This review intends to give an overview of the existing articles in this emerging field of enzyme-catalysed RAFT polymerization with a special focus on novel strategies for the enzyme-initiated RAFT method, including cascade-catalysed RAFT, RAFT-mediated polymerization-induced self-assembly (RAFT-PISA), photo-enzymatic RAFT and "grafting from" RAFT. It also provides an outlook on the burgeoning role of enzymes in the green and high-throughput synthesis of sustainable and precision RAFT polymers under mild conditions with high efficiency, specificity and selectivity and further discusses the opportunities and insights into enzymatic catalyses to yield novel polymers for biomedical use via green polymer chemistry.

The synthesis of fluorescent hybrid nanomaterials engineered via the chain-end modification of reversible addition-fragmentation chain-transfer (RAFT) polymers on the surface of bovine serum albumin (BSA) protein-stabilized gold nanoclusters (AuNCs@BSA) is described. Based on the “grafting-to” approach the core-shell structured nanoconjugates AuNCs@BSA/polymer are generated via effective ligation of hydrophilic, and stimuli-responsive polymers. Such nanomaterials are characterized via various microscopic and spectroscopic studies and exhibit their size as ≈5 nm and emission peak at ≈650 nm. Interestingly, the conjugation of thermoresponsive polymer poly(diethylene glycol monomethyl ether methacrylate) (PDEGMA) transformed the nanoconjugates AuNCs@BSA/PDEGMA as dual thermo/pH-responsive nanomaterials.

In this review, various types of synthetic polymer-based inhibitors of amyloid-β aggregations are discussed for their potential development as therapeutic agents for Alzheimer's disease treatment.

Targeting germline (gl-) precursors of broadly neutralizing antibodies (bNAbs) is acknowledged as an important strategy for HIV-1 vaccines. The VRC01-class of bNAbs is attractive because of its distinct genetic signature. However, VRC01-class bNAbs often require extensive somatic hypermutation, including rare insertions and deletions. We describe a BG505 SOSIP trimer, termed GT1.2, to optimize binding to gl-CH31, the unmutated common precursor of the CH30-34 bNAb lineage that acquired a large CDRH1 insertion. The GT1.2 trimer activates gl-CH31 naive B cells in knock-in mice, and B cell responses could be matured by selected boosting immunogens to generate cross-reactive Ab responses. Next-generation B cell sequencing reveals selection for VRC01-class mutations, including insertions in CDRH1 and FWR3 at positions identical to VRC01-class bNAbs, as well as CDRL1 deletions and/or glycine substitutions to accommodate the N276 glycan. These results provide proof of concept for vaccine-induced affinity maturation of B cell lineages that require rare insertions and deletions.

Natural products are being targeted as alternative anticancer agents due to their non-toxic and safe nature. The present study was conducted to explore the in vitro anticancer potential of Justicia adhatoda (J. adhatoda) leaf extract. The methanolic leaf extract was prepared, and the phytochemicals and antioxidant potential were determined by LCMS analysis and DPPH radical scavenging assay, respectively. A docking study performed with five major alkaloidal phytoconstituents showed that they had a good binding affinity towards the active site of NF-κB. Cell viability assay was carried out in five different cell lines, and the extract exhibited the highest cytotoxicity in MCF-7, a breast cancer cell line. Extract-treated cells showed a significant increase in nitric oxide and reactive oxygen species production. Cell cycle analysis showed an arrest in cell growth at the Sub-G0 phase. The extract successfully inhibited cell migration and colony formation and altered mitochondrial membrane potential. The activities of superoxide dismutase and glutathione were also found to decrease in a dose-dependent manner. The percentage of apoptotic cells was found to increase in a dose-dependent manner in MCF-7 cells. The expressions of caspase-3, Bax, and cleaved-PARP were increased in extract-treated cells. An increase in the expression of NF-κB was found in the cytoplasm in extract-treated cells. J. adhatoda leaf extract showed a potential anticancer effect in MCF-7 cells.

Chronic arsenic (As) poisoning is mostly due to subsoil water contaminated with As and its salts. Exposure to As has been found to cause an elevation in reactive oxygen species (ROS), leading to the damage of DNA and proteins, and it also causes immunotoxicity. Treatment regimens are primarily based on chelation therapy and amino acid and vitamin supplementations. Recent studies have established that natural products display effective and progressive relief from arsenicosis without any side effects. β-glucogallin (BGG), a gallo-tannin natural product, is reported to possess anti-oxidant and anti-inflammatory properties. In the present study, we aim to observe the protective role of BGG against As-induced cytotoxicity, apoptosis, mitochondrial dysfunction, and the underlying mechanisms in RAW 264.7 macrophage cells. We found that BGG alleviates As-induced ROS, apoptosis, and mitochondrial dysfunction in RAW 264.7 macrophage cells. Thus, BGG can be used therapeutically to prevent As-induced toxicity.

SARS-CoV-2, the newly emerged virus of the Coronaviridae family is causing havoc worldwide. The novel coronavirus 2019 was first reported in Wuhan, China marked as the third highly infectious pathogenic virus of the twenty-first century. The typical manifestations of COVID-19 include cough, sore throat, fever, fatigue, loss of sense of taste and difficulties in breathing. Large numbers of SARS-CoV-2 infected patients have mild to moderate symptoms, however severe and life-threatening cases occur in about 5–10% of infections with an approximately 2% mortality rate. For the treatment of SARS-CoV-2, the use of neutralizing monoclonal antibodies (mAbs) could be one approach. The receptor binding domain (RBD) and N-terminal domain (NTD) situated on the peak of the spike protein (S-Protein) of SARS-CoV-2 are immunogenic in nature, therefore, can be targeted by neutralizing monoclonal antibodies. Several bioinformatics approaches highlight the identification of novel SARS-CoV-2 epitopes which can be targeted for the development of COVID-19 therapeutics. Here we present a summary of neutralizing mAbs isolated from COVID-19 infected patients which are anticipated to be a better therapeutic alternative against SARS-CoV-2. However, provided the vast escalation of the disease worldwide affecting people from all strata, affording expensive mAb therapy will not be feasible. Hence other strategies are also being employed to find suitable vaccine candidates and antivirals against SARS-CoV-2 that can be made easily available to the population.

Targeting germline (gl-) precursors of broadly neutralizing antibodies (bNAbs) is acknowledged as an important strategy for HIV-1 vaccines. The VRC01-class of bNAbs is attractive because of its distinct genetic signature. However, VRC01-class bNAbs often require extensive somatic hypermutation, including rare insertions and deletions. We designed a BG505 SOSIP trimer, termed GT1.2, to optimize binding to gl-CH31, the unmutated precursor of the CH30-34 bNAb lineage that acquired a large CDRH1 insertion. The GT1.2 trimer activated gl-CH31 naive B cells in knock-in mice and B cell responses could be matured by selected boosting immunogens to generate cross-reactive Ab responses. Next-generation B cell sequencing revealed selection for VRC01-class mutations, including insertions in CDRH1 and FWR3 at positions identical to VRC01-class bNAbs, as well as CDRL1 deletions and/or glycine substitutions to accommodate the N276 glycan. These results provide proof-of-concept for vaccine-induced affinity maturation of B cell lineages that require rare insertions and deletions.Funding Information: This work is supported by the Netherlands Organization for Scientific Research (NWO) Vici grant (RWS), Bill & Melinda Gates Foundation, Collaboration for AIDS Vaccine Discovery (CAVD) grant INV-002022 (RWS) and OPP1115782/INV-002916 (ABW), Fondation Dormeur, Vaduz (RWS), as well as grants from the NIH/National Institute of Allergy and Infectious Diseases: NIAID, Division of AIDS, NIH UM1 grants for the Duke Center for HIV/AIDS Vaccine Immunology-Immunogen Discovery (CHAVI-ID; UM1530AI100645 and Consortia for HIV/AIDS Vaccine Development (CHAVD) UM1AI144371 to BFH and R01 grant AI087202 (LKV). PJK and JPM are supported by R01 AI036082 and ABW, IAW, RWS, PJK and JPM are supported by a HIVRAD P01 AI110657 grant. MC is funded by the International AIDS Vaccine Initiative (IAVI) through grant INV-008352 and Bill & Melinda Gates Foundation OPP1153692. Funding for the neutralization assays was provided by NIH/NIAID contract #HHSN272201800004CDeclaration of Interests: Amsterdam UMC has filed a patent application related to germline-targeting HIV-1 Env trimers.Ethics Approval Statement: All animal procedures performed were approved by Duke or CMII Institutional Animal Care and Use Committees (IACUC)-approved protocols.

3D bioprinting has gathered particular attention in the past few years as a remarkable cell-printing technology for the ultimate goal of biomanufacturing artificial 3D constructs and living organs toward tissue engineering and regenerative medicinal applications. Such an advanced method provides the opportunity to fabricate customized and patient-specific tissue scaffolds and medical device geometries with controlled spatial resolution and printability. Recently, hydrogels have evoked as an ideal candidate for the bioink-formulation of 3D printing due to their aqueous and 3D networked environment. This review article aims to summarize the articles documenting the 3D printable nature-inspired hydrogel inks comprised from synthetic polymers and natural polymers for biobased applications. Furthermore, the chemical insights for the hydrogel biomaterials are discussed, which can offer optimizable mechanical, functional, and chemical properties for enabling fabricated 3D objects with shape fidelity. Different approaches for engineering 3D scaffolds are also presented in order to understand and improve their mechanics and biological properties.

Incessant antigenic evolution enables the persistence and spread of influenza virus in the human population. As the principal target of the immune response, the hemagglutinin (HA) surface antigen on influenza viruses continuously acquires and replaces N-linked glycosylation sites to shield immunogenic protein epitopes using host-derived glycans. Anti-glycan antibodies, such as 2G12, target the HIV-1 envelope protein (Env), which is even more extensively glycosylated and contains under-processed oligomannose-type clusters on its dense glycan shield. Here, we illustrate that 2G12 can also neutralize human seasonal influenza A H3N2 viruses that have evolved to present similar oligomannose-type clusters on their HAs from around 20 years after the 1968 pandemic. Using structural biology and mass spectrometric approaches, we find that two N-glycosylation sites close to the receptor binding site (RBS) on influenza hemagglutinin represent the oligomannose cluster recognized by 2G12. One of these glycan sites is highly conserved in all human H3N2 strains and the other emerged during virus evolution. These two N-glycosylation sites have also become crucial for fitness of recent H3N2 strains. These findings shed light on the evolution of the glycan shield on influenza virus and suggest 2G12-like antibodies can potentially act as broad neutralizers to target human enveloped viruses.

Ebola virus (EBOV) glycoprotein (GP) can be recognized by neutralizing antibodies (NAbs) and is the main target for vaccine design. Here, we first investigate the contribution of the stalk and heptad repeat 1-C (HR1(C)) regions to GP metastability. Specific stalk and HR1(C) modifications in a mucin-deleted form (GP Delta muc) increase trimer yield, whereas alterations of HR1(C) exert a more complex effect on thermostability. Crystal structures are determined to validate two rationally designed GP Delta muc trimers in their unliganded state. We then display a modified GP Delta muc trimer on reengineered protein nanoparticles that encapsulate a layer of locking domains (LD) and a cluster of helper T-cell epitopes. In mice and rabbits, GP trimers and nanoparticles elicit cross-ebolavirus NAbs, as well as non-NAbs that enhance pseudovirus infection. Repertoire sequencing reveals quantitative profiles of vaccine-induced B-cell responses. This study demonstrates a promising vaccine strategy for filoviruses, such as EBOV, based on GP stabilization and nanoparticle display. Ebola virus glycoprotein (GP) is a major target for vaccine design. Here, the authors identify mutations to improve GP stability and yield, design two multilayered nanoparticle carriers, and demonstrate good immunogenicity of the modified GP on nanoparticles in mice and rabbits.

A fluorescent staining procedure based upon thioflavin T is described. This dye permits rapid, vital, nonprecipitative staining of human reticulocytes. Flow cytometric analysis of thioflavin T stained whole blood specimens results in reticulocyte counts that correlate well with new methylene blue reticulocyte counts and give coefficients of variation approaching the theoretical limit. The shape of the fluorescence histogram is qualitatively similar to the reticulocyte age profile. Paired new methylene blue and thioflavin T reticulocyte counts are presented with illustrative cases of reticulocyte maturity distributions.

In this review ink/bioink materials comprised of synthetic polymers as single network precursor are discussed for extrusion-based 3D printing for their potential biological applications.

An amyloid-β-peptide-derived chain-transfer agent has been synthesized and employed to obtain well defined, peptide–polymeric conjugates, able to assemble into mechanically strong cross-linked hydrogels.

BNAbs of V H 1-69 germline origin from a Chinese patient recognize the V3 glycan supersite via a disulfide-locked long HCDR3 loop.

ABSTRACT Antigen-specific B-cell sorting and next-generation sequencing (NGS) were combined to isolate HIV-1 neutralizing antibodies (NAbs) from mice and rabbits immunized with BG505 trimers and nanoparticles. Three mouse NAbs potently neutralize BG505.T332N and recognize a glycan epitope centered at the C3/V4 region, as revealed by electron microscopy (EM), x-ray crystallography, and epitope mapping. Three potent NAbs were sorted from rabbit B cells that target glycan holes on the BG505 envelope glycoprotein (Env) and account for a significant portion of autologous NAb response. We then determined a 3.4Å-resolution crystal structure for the clade C transmitted/founder Du172.17 Env with a redesigned heptad repeat 1 (HR1) bend. This clade C Env, as a soluble trimer and attached to a ferritin nanoparticle, along with a clade A Q482-d12 Env trimer, elicited distinct NAb responses in rabbits. Our study demonstrates that nanoparticles presenting gp41-stabilized trimers can induce potent NAb responses in mice and rabbits with Env-dependent breadth. TEASER Mouse and rabbit NAbs elicited by gp41-stabilized trimers and nanoparticles neutralize autologous HIV-1 by targeting different epitopes

The synthesis and self-assembly of peptide-polymer conjugates into fibrillar nanostructures are reported, based on the amyloidogenic peptide KLVFF. A strategy for rational synthesis of polymer-peptide conjugates is documented via tethering of the amyloidogenic peptide segment LVFF (Aβ17-20 ) and its modified derivative FFFF to the hydrophilic poly(ethylene glycol) monomethyl ether (mPEG) polymer via thio-bromo based "click" chemistry. The resultant conjugates mPEG-LVFF-OMe and mPEG-FFFF-OMe are purified via preparative gel permeation chromatography technique (with a yield of 61% and 64%, respectively), and are successfully characterized via combination of spectroscopic and chromatographic methods, including electrospray ionization time-of-flight mass spectrometry. The peptide-guided self-assembling behavior of the as-constructed amphiphilic supramolecular materials is further investigated via transmission electron microscopic and circular dichroism spectroscopic analysis, exhibiting fibrillar nanostructure formation in binary aqueous solution mixture.

In view of the potential applications of fibers in material sciences and biomedicine, an effective synthetic strategy is described to construct peptide-based bifunctional polymeric conjugates for supramolecular self-association in solution. A direct coupling method of an α-acyl-brominated peptide Phe-Phe-Phe-Phe (FFFF) with a disulfide-bridged polymeric scaffold of poly(ethylene glycol) (PEG) (Mn,GPC = 8700 g mol–1, Đ = 2.02) is reported to readily prepare the bi-headed conjugate FFFF-PEG-FFFF (Mn,GPC = 3800 g mol–1, Đ = 1.10) via a one-pot, tandem disulfide reduction (based on tris(2-carboxyethyl)phosphine hydrochloride (TCEP)) coupled to a thio-bromo “click” reaction. The conjugate was investigated via transmission electron microscopy to exploit supramolecular fibril formation and solvent-dependent structuring into macroscale fibers via fibril–fibril interactions and interfibril cross-linking-induced bundling. Circular dichroism spectroscopic analysis is further performed to investigate β-sheet motifs in such fibrous scaffolds. Overall, this synthetic approach opens an attractive approach for a simplified synthesis of PEG-containing peptide conjugates.