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Bioconjugate Chemistry

Lei Li, Dian Li, Mingzu Zhang, Jinlin He, Jian Liu, Peihong Ni
Shell cross-linked (SCL) polymeric prodrug micelles have the advantages of good blood circulation stability and high drug content. Herein, we report on a new kind of pH/redox responsive dynamic covalent SCL micelles, which was fabricated by self-assembly of a multifunctional polymeric prodrug. At first, a macroinitiator PBYP- ss- iBuBr was prepared via ring-opening polymerization (ROP), wherein PBYP represents poly[2-(but-3-yn-1-yloxy)-2-oxo-1,3,2-dioxaphospholane]. Subsequently, PBYP- hyd-DOX- ss-P(DMAEMA- co-FBEMA) prodrug was synthesized by one-pot method with a combination of atom transfer radical polymerization (ATRP) and Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) reaction using a doxorubicin (DOX) derivative containing azide group to react with the alkynyl group of the side chain in the PBYP block, while DMAEMA and FBEMA are the abbriviations of N,N-(2-dimethylamino)ethyl methacrylate and 2-(4-formylbenzoyloxy)ethyl methacrylate, respectively...
July 13, 2018: Bioconjugate Chemistry
Marieke Poß, Eva Zittel, Anna Meschkov, Ute Schepers, Claus Feldmann
Sulfonate-based inorganic-organic hybrid nanoparticles (IOH-NPs) with the general saline composition [Gd(OH)]2+n/2[Rdye(SO3)n]n- showing optical absorption and emission in the blue to red spectral regime are presented for the first time. All IOH-NPs are prepared via straightforward aqueous synthesis and instantaneously result in colloidally highly stable suspensions with mean particle diameters of 40-50 nm and high zeta potentials (-20 to -40 mV at pH 7.0). Specifically, the IOH-NPs comprise [Gd(OH)]2+2[CSB]4-, [Gd(OH)]2+2[DB71]4-, [Gd(OH)]2+[NFR]2-, [Gd(OH)]2+[AR97]2-, and [Gd(OH)]2+2[EB]4- showing blue, orange, red and infrared absorption and emission ([CSB]: Chicago Sky Blue; [DB71]: Direct Blue 71; [NFR]: Nuclear Fast Red; [AR97]: Acid Red 97; [EB]: Evans Blue)...
July 13, 2018: Bioconjugate Chemistry
Rachel B Kozlowski, Ashwin Ragupathi, R Brian Dyer
Functional enzyme-nanoparticle bioconjugates are increasingly important in biomedical and biotechnology applications such as drug delivery and biosensing. Optimization of the function of such bioconjugates requires careful control and characterization of their structures and activity, but current methods are inadequate for this purpose. A key shortcoming of existing approaches is the lack of an accurate method for quantitating protein content of bioconjugates for low (monolayer) surface coverages. In this study, an integrated characterization methodology for protein-gold nanoparticle (AuNP) bioconjugates is developed, with a focus on site-specific attachment and surface coverage of protein on AuNPs...
July 13, 2018: Bioconjugate Chemistry
Sylwia A Dragulska, Ying Chen, Marek T Wlodarczyk, Mina Poursharifi, Peter Dottino, Rein V Ulijn, John A Martignetti, Aneta Joanna Mieszawska
We report a nanoemulsion (NE) which is stabilized by self-assembling tripeptide lysine-tyrosine-phenylalanine (KYF) and encapsulates an oleic acids-platinum conjugate formed using a simple Pt (II) coordination chemistry. The KYF-Pt-NE is evaluated both in cultured ovarian cancer cells and in an in vivo preclinical cancer model and shows pH dependent Pt (II) release, which is low at physiological pH and enhanced at tumoral pH. The biological activity of KYF-Pt-NE, evaluated in multiple ovarian cancer cell lines, is significantly higher when compared to analogous Pt (II) complex used in the clinic...
July 12, 2018: Bioconjugate Chemistry
Luis A Navarro, Daniel L French, Stefan Zauscher
Proteoglycans are important brush-like biomacromolecules which serve a variety of functions in the human body. While protein-bottlebrush hybrids are promising proteoglycan mimics, many challenges still exist to robustly produce such polymers. In this paper, we report the modular synthesis of protein-brush hybrids containing elastin-like polypeptides (ELP) as model proteins by copper-catalyzed azide-alkyne cycloaddition. We exploit the recently discovered imidazole-1-sulfonyl azide (ISA) in a diazotransfer reaction to introduce an N-terminal azide onto an ELP...
July 12, 2018: Bioconjugate Chemistry
Okhil Kumar Nag, Jawad Naciri, Jeffrey S Erickson, Eunkeu Oh, James B Delehanty
Current challenges in photodynamic therapy (PDT) include both the targeted delivery of the photosensitizer (PS) to the desired cellular location and the maintenance of PS efficacy. Zinc phthalocyanine (ZnPc), a macrocyclic porphyrin and a potent PS for PDT, undergoes photoexcitation to generate reactive singlet oxygen that kills cells efficiently, particularly when delivered to the plasma membrane. Like other commonly-employed PS, ZnPc is highly hydrophobic and prone to self-aggregation in aqueous biological media...
July 10, 2018: Bioconjugate Chemistry
Diego Bouzas Ramos, Laura Trapiella-Alfonso, Kelly Pons, Jorge Ruiz Encinar, Jose Manuel Costa-Fernandez, Vassilis Tsatsaris, Nathalie Gagey-Eilstein
The use of functionalized magnetic particles is increasing because they simplify the analytical process and yield promising results in a wide range of applications. Particularly, streptavidin-coated magnetic beads offer the possibility of rapid and very efficient grafting of biomolecules. Unfortunately, current methods to monitor and compute this grafting process are cumbersome and scarce. We describe herein a simple, rapid and reliable chemiluminescent assay we have developed to check the grafting rate of functionalized magnetic beads...
July 10, 2018: Bioconjugate Chemistry
Yao Lu, Lihua Li, Mei Li, Zefeng Lin, Liping Wang, Yu Zhang, Qingshui Yin, Hong Xia, Gang Han
Zero-dimensional carbon dots (CD) and their effects on osteogenesis have been rarely studied in bone repair materials. Here, we fabricate the first novel CD doped chitosan/nano-hydroxyapatite (CS/nHA/CD) scaffold with full potential to promote bone regeneration by a facile freeze-drying method. The CS/nHA/CD scaffolds enhanced cell adhesion and osteoinductivity in rat bone mesenchymal stem cells by up-regulating genes involved in focal adhesion and osteogenesis in vitro, which significantly improved the formation of vascularized new bone tissue at 4 weeks compared to pure CS/nHA scaffolds in vivo...
July 9, 2018: Bioconjugate Chemistry
Muhammad R Haque, Jee-Heon Jeong, Kyo Won Lee, Du Yeon Shin, Geun-Soo Kim, Sung Joo Kim, Youngro Byun
The microenvironment of pancreatic islets gets disrupted during enzyme digestion and causes islets to remain in vulnerable state, leading to poor outcome in the initial days of transplantation. To avoid immune invasion while allowing the reconstruction of microenvironment of the transplanted site, we propose immunoisolation polymers, which can nano-encapsulate islets quickly without cytotoxicity. Here, non-human primate (NHP) islets were nano-encapsulated with hyperbranched polyethylene glycol (hb-PEG) and heparin by layer-by-layer technology and transplanted into the kidney subcapsular space of diabetic C57BL/6 mice...
July 9, 2018: Bioconjugate Chemistry
Gousia Begum, Shikha Lalwani, Rohit Kumar Rana
Spatial confinement of Glucose oxidase (GOx) in the hollow interior of a bio-inspired matrix via polyamine mediated silica nanoparticle assembly under environmentally benign conditions is demonstrated herein. In a similarity to the biosilicification processes in Diatoms, we use polyallylamine hydrochloride (PAH) to direct the assembly of silica nanoparticles on CaCO3 spheres as the removable core. When this assembly process is performed on the CaCO3 spheres, which are pre-loaded with GOx in a post-synthesis method, microspheres encapsulating GOx are formed...
July 6, 2018: Bioconjugate Chemistry
Antonietta Maria Lillo, Ciana Lopez, Trideep Rajale, Hung-Ju Yen, Harsha Magurudeniya, M Lisa Phipps, Eva Rose Murdock Balog, Timothy C Sanchez, Srinivas Iyer, Hsing-Lin Wang, Ryszard Michalczyk, Reginaldo C Rocha, Jennifer S Martinez
Protein-ligand conjugations are usually carried out in aqueous media in order to mimic the environment within which the conjugates will be used. In this work, we focus on the conjugation of amphiphilic variants of elastin-like polypeptide (ELP), short elastin (sEL), to poorly water-soluble compounds like OPPVs (p-phenylene vinylene oligomers), triarylamines, and polypyridine-metal complexes. These conjugations are problematic when carried out in aqueous phase because hydrophobic ligands tend to avoid exposure to water, which in turn causes the ligand to self-aggregate and/or interact non-covalently with hydrophobic regions of the amphiphile...
July 6, 2018: Bioconjugate Chemistry
Elita Montanari, Maria Pelliccia, Arianna Gennari, Lucio Manzi, Roberto Donno, Neil J Oldham, Andrew MacDonald, Nicola Tirelli
We present a method for site-selective and reversible bioconjugation; tyrosines are enzymatically converted into catechols and in situ 'clicked' onto boronic acids. Importantly, our process selectively produces catechols and avoids quinones, thereby improving the control over the chemical identity of the products. We have conjugated boronic acid-containing hyaluronic acid (HyA) to peptides bearing tyrosines in variable number and position; the use of tagging peptides - in our case the hemagglutinin-derived HA-tag - makes our approach applicable to virtually any protein; we have demonstrated this concept by conjugating HA-tagged ovalbumin to HyA, thereby also showing the feasibility of producing chimeric proteoglycans...
July 5, 2018: Bioconjugate Chemistry
Sibaprasad Maity, Apurba Pramanik, Yuri L Lyubchenko
Amyloid oligomers are considered the most neurotoxic species of amyloid aggregates. Spontaneous assembly of amyloids into aggregates is recognized as a major molecular mechanism behind Alzheimer's disease and other neurodegenerative disorders involving protein aggregation. Characterization of such oligomers is extremely challenging, but complicated by their transient nature. Previously, we introduced a flexible nano-array (FNA) method enabling us to probe dimers assembled by the amyloid β (14-23) [Aβ (14-23)] peptide...
July 5, 2018: Bioconjugate Chemistry
Daiki Terada, Shingo Sotoma, Yoshie Harada, Ryuji Igarashi, Masahiro Shirakawa
Fluorescent nanodiamonds (FNDs) have been attracting much attention as promising therapeutic agents and probes for bioimaging and nanosensing. For their biological applications, several hydrophilizing methods to enhance FND colloidal stability have been developed to suppress their aggregation and the nonspecific adsorption to biomolecules in complex biomedical environments. However, these methods involve several complicated synthetic and purification steps, which prohibit the use of FNDs for bioapplications by biologists...
July 5, 2018: Bioconjugate Chemistry
Rindia M Putri, Habiburrahman Zulfikri, Jean Wilfried Fredy, Alberto Juan, Pichayut Tananchayakul, Jeroen J L M Cornelissen, Melissa S T Koay, Claudia Filippi, Nathalie Katsonis
Developing strategies to interfere with allosteric interactions in proteins not only promises to deepen our understanding of vital cellular processes but also allows their regulation using external triggers. Light is particularly attractive as a trigger being spatiotemporally selective and compatible with the physiological environment. Here, we engineered a hybrid protein in which irradiation with light opens a new allosteric communication route that is not inherent to the natural system. We select human serum albumin, a promiscuous protein responsible for transporting a variety of ligands in plasma, and show that by covalently incorporating a synthetic photoswitch to subdomain IA we achieve optical control of the ligand binding in subdomain IB...
July 5, 2018: Bioconjugate Chemistry
Simon Leclerc, Youri Arntz, Yuichi Taniguchi
Fluorescence-based electrophoresis has been widely used for proteome analysis, in which every protein species in cells are labeled with a fluorescent dye, separated by electric migration and are quantified using fluorescence detection. The ultimate limit of sensitivity for this approach could be reached by single-molecule fluorescence imaging and counting individual proteins, requiring exhaustive fluorescent labeling of proteins across molecular populations and species. However, it remains unclear how homogeneous is the fluorescence labeling of individual protein molecules of each species across the proteome...
July 5, 2018: Bioconjugate Chemistry
Brendon E Cook, Rosemery Membreno, Brian M Zeglis
The development of immunoconjugates requires a careful balance between preserving the functionality of the antibody and modifying the immunoglobulin with the desired cargo. Herein, we describe the synthesis, development, in vivo evaluation of a novel bifunctional dendrimeric scaffold (DBCO-Ygg-TCO) and its application in pretargeted PET imaging. The site-specific modification of the huA33 antibody with this dendrimeric scaffold yields an immunoconjugate - ss huA33-Ygg-TCO - decorated with ~8 trans-cyclooctene (TCO) moieties, a marked increase compared to the ~2 TCO/mAb of a non-dendrimeric control immunoconjugate (ss huA33-PEG12 -TCO)...
July 3, 2018: Bioconjugate Chemistry
Euna Yoo, Alex C D Salyer, Michael J H Brush, Yupeng Li, Kathryn L Trautman, Nikunj M Shukla, Ans De Beuckelaer, Stefan Lienenklaus, Kim Deswarte, Bart Lambrecht, Bruno G De Geest, Sunil A David
Immunogens carried in lymphatic fluid drain via afferent vessels into regional lymph nodes and facilitate the efficient induction of appropriate immune responses. The lymphatic system possesses receptors recognizing hyaluronic acid (HA). Covalent conjugates of small-molecule TLR7/8 agonists with HA are entirely devoid of immunostimulatory activity in vitro. In murine models of immunization, however, such conjugates traffic to lymph nodes, where they are 'unmasked', releasing the small molecule TLR7/8 agonist from the carrier polysaccharide...
July 3, 2018: Bioconjugate Chemistry
Carlos Fernandes, Sofia Benfeito, Ricardo Amorim, Jose Teixeira, Paulo J Oliveira, Fernando Remião, Fernanda Borges
Mitochondrial oxidative damage contributes to a wide range of pathologies, including cancer, cardiovascular disorders and neurodegenerative diseases. Protecting mitochondria from oxidative damage with mitochondriotropic antioxidants is looked as an effective therapeutic strategy. Despite the success of the approach some concerns related with their cytotoxicity have been reported. For instance, AntiOxCIN6, is a mitochondriotropic antioxidant based on caffeic acid (CAF) that is cytotoxic in hepatocarcinoma (HepG2) cell lines...
July 2, 2018: Bioconjugate Chemistry
Chimdiya Onwukwe, Nuzhat Maisha, Mark Holland, Matt Varley, Rebecca Groynom, DaShawn Hickman, Nishant Uppal, Andrew Shoffstall, Jeffrey Ustin, Erin B Lavik
Bleeding from traumatic injury is the leading cause of death for young people across the world, but interventions are lacking. While many agents have shown promise in small animal models, translating the work to large animal models has been exceptionally difficult in great part because of infusion-associated complement activation to nanomaterials that leads to cardiopulmonary complications. Unfortunately, this reaction is seen in at least 10% of the population. We developed intravenously infusible hemostatic nanoparticles that were effective in stopping bleeding and improving survival in rodent models of trauma...
July 2, 2018: Bioconjugate Chemistry
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