39684-80-5Relevant academic research and scientific papers
In vitro and in vivo evaluation of 99mTc-DO3A-EA-Folate for receptor-mediated targeting of folate positive tumors
Mishra, Gauri,Hazari, Puja Panwar,Kumar, Nitin,Mishra, Anil K.
, p. 761 - 769 (2011)
Background: The cell membrane folate receptor is a potential molecular target for tumor selective drug delivery via receptor-mediated endocytosis, including delivery of radiolabeled folate-chelate conjugates for diagnostic imaging. Method: A new radiopharmaceutical, 99mTc-1,4,7-tris (carboxymethyl)-10-(4-aminoethyl)-1,4,7,10-tetraazacyclododecane (DO3A-EA)-Folate has been synthesized introducing DO3A-EA to the γ-carboxyl group of folic acid and was characterized by different spectroscopic techniques. Cytotoxicity was determined by macrocolony and MTT assay on three different cell lines. Cell uptake studies and receptor binding assay were performed using 99mTc-DO3A-EA-Folate. Tumor imaging was performed in KB cell line implanted tumor bearing nude mice, and uptake of the radiotracer was estimated. Results: The synthesized conjugate binds with 99mTc at high efficiency at ambient temperature. The resulting conjugate is stable under physiological conditions for 24h after radiocomplexation. Using an in vitro receptor binding assay, the conjugate showed Kd in μM range on human tumor cell lines (KB, U-87MG and OAW). The pharmacokinetic data revealed rapid wash out of the more than 75% activity within 5min from the circulation with hepato-biliary clearance. Data from γ scintigraphic and biodistribution studies performed in KB tumor bearing nude mice revealed major accumulation of radiotracer at tumor site. High tumor uptake was shown in the tumor bearing mice; tumor to blood ratios reached 2.27±0.32 and 6.05±1.02 at 1 and 4h after post injection, respectively. Conclusion: These results suggest that 99mTc-DO3A-EA- Folate may be clinically useful as a noninvasive radiodiagnostic imaging agent for the detection of FR-positive human cancers.
Manganese Complex of a Rigidified 15-Membered Macrocycle: A Comprehensive Study
Freire, David M.,Green, Kayla N.,Kálmán, Ferenc Krisztián,Molnár, Enik?,Pota, Kristof,Tircsó, Gyula
, (2020)
Owing to the increasing importance of manganese(II) complexes in the field of magnetic resonance imaging (MRI), large efforts have been devoted to find an appropriate ligand for Mn(II) ion encapsulation by providing balance between the seemingly contradictory requirements (i.e., thermodynamic stability and kinetic inertness vs low ligand denticity enabling water molecule(s) to be coordinated in its metal center). Among these ligands, a large number of pyridine or pyridol based open-chain and macrocyclic chelators have been investigated so far. As a next step in the development of these chelators, 15-pyN3O2Ph and its transition metal complexes were synthesized and characterized using established methods. The 15-pyN3O2Ph ligand incorporates both pyridine and ortho-phenylene units to decrease ligand flexibility. The thermodynamic properties, protonation and stability constants, were determined using pH-potentiometry; the solid-state structures of two protonation states of the free ligand and its manganese complex were obtained by single crystal X-ray diffractometry. The results show a seven-coordinate metal center with two water molecules in the first coordination sphere. The longitudinal relaxivity of [Mn(15-pyN3O2Ph)]2+ was found to be 5.16 mM-1 s-1 at 0.49 T (298 K). Furthermore, the r2p value of 11.72 mM-1 s-1 (0.49 T), which is doubled at 1.41 T field, suggests that design of this Mn(II) complex does achieve some characteristics required for contrast imaging. In addition, 17O NMR measurements were performed in order to access the microscopic parameters governing this key feature (e.g., water exchange rate). Finally, manganese complexes of ligands with analogous polyaza macrocyclic scaffold have been investigated as low molecular weight Mn(CAT) mimics. Here, we report the H2O2 disproportionation study of [Mn(15-pyN3O2Ph)]2+ to demonstrate the versatility of this ligand scaffold as well.
Silver-guided excimer emission in an adenine-pyrene conjugate: fluorescence lifetime and crystal studies
Pandey, Mrituanjay D.,Mishra, Ashutosh Kumar,Chandrasekhar, Vadapalli,Verma, Sandeep
, p. 2020 - 2022 (2010)
This Communication describes a novel adenine-pyrene conjugate (1) and its solid-state structure with silver and copper ions. Singlecrystal studies of metal complexes of 1 offer insight into molecular interactions and provide a basis to rationalize possible interactions in the solution state, leading to excimer formation. The robust nature of this interaction was further confirmed by deposition of the silver complex on a graphite surface, which exhibited a remarkable resemblance to its solid-state structure. The structural basis of selective excimer formation in the presence of Ag+ ions presents a viable approach for ratiometric detection of these ions.
Tetrazole-based trans-translation inhibitors kill Bacillus anthracis spores to protect host cells
Alumasa, John N.,Goralski, Tyler D. P.,Keiler, Kenneth C.
, (2017)
Bacillus anthracis, the causative agent of anthrax, remains a significant threat to humans, including potential use in bioterrorism and biowarfare. The capacity to engineer strains with increased pathogenicity coupled with the ease of disseminating lethal
Enhanced Out-of-Plane Conductivity and Photovoltaic Performance in n = 1 Layered Perovskites through Organic Cation Design
Passarelli, James V.,Fairfield, Daniel J.,Sather, Nicholas A.,Hendricks, Mark P.,Sai, Hiroaki,Stern, Charlotte L.,Stupp, Samuel I.
, p. 7313 - 7323 (2018)
Layered perovskites with the formula (R-NH3)2PbI4 have excellent environmental stability but poor photovoltaic function due to the preferential orientation of the semiconducting layer parallel to the substrate and the typically insulating nature of the R-NH3+ cation. Here, we report a series of these n = 1 layered perovskites with the form (aromatic-O-linker-NH3)2PbI4 where the aromatic moiety is naphthalene, pyrene, or perylene and the linker is ethyl, propyl, or butyl. These materials achieve enhanced conductivity perpendicular to the inorganic layers due to better energy level matching between the inorganic layers and organic galleries. The enhanced conductivity and visible absorption of these materials led to a champion power conversion efficiency of 1.38%, which is the highest value reported for any n = 1 layered perovskite, and it is an order of magnitude higher efficiency than any other n = 1 layered perovskite oriented with layers parallel to the substrate. These findings demonstrate the importance of leveraging the electronic character of the organic cation to improve optoelectronic properties and thus the photovoltaic performance of these chemically stable low n layered perovskites.
Bioinspired adenine-dopamine immobilized polymer hydrogel adhesives for tissue engineering
Joshi, Saurabh,Mahadevan, Gomathi,Verma, Sandeep,Valiyaveettil, Suresh
, p. 11303 - 11306 (2020)
Nontoxic adhesive hydrogels are of great importance in tissue engineering. Herein, we report a simple synthesis of a few biocompatible hydrogels from adenine and dopamine immobilized polyacrylic acid (PAA) and alginic acid (Alg) polymers. The adenine-dopamine adduct incorporated hydrogels showed enhanced adhesiveness, transparency and biocompatibility, and induced cell proliferation in 2D and 3D-cell culture models within 24 h. Moreover, blending the modifiedPAAand Alg polymers (P2P4) further increased the stability and bioactivity of the hydrogel. Such biogels can be developed as smart materials for biomedical applications.
Exploring hydrogen bonding and weak aromatic interactions induced assembly of adenine and thymine functionalised naphthalenediimides
Narayanaswamy, Nagarjun,Avinash,Govindaraju
, p. 1302 - 1306 (2013)
Adenine and thymine functionalised naphthalenediimide (NDI) conjugates and complementary peptide nucleic acid (PNA) dimers are designed to exploit complementary hydrogen bonding and aromatic interactions for controllable molecular organization. These nucleobase appended NDIs organized into well-defined fibers, nanoribbons, porous spheres, belts and petal-like 2D sheets.
Synthesis of novel conjugates of a saccharide, amino acids,nucleobase and the evaluation of their cell compatibility
Yuan, Dan,Du, Xuewen,Shi, Junfeng,Zhou, Ning,Baoum, Abdulgader Ahmed,Xu, Bing
, p. 2406 - 2413 (2014)
This article reports the synthesis of a novel type of conjugate of three fundamental biological build blocks (i.e., saccharide, amino acids, and nucleobase) and their cell compatibility. The facile synthesis starts with the synthesis of nucleobase and saccharide derivatives, then uses solid-phase peptide synthesis (SPPS) to build the peptide segment (Phe-Arg-Gly-Asp or naphthAla-Phe-Arg- Gly-Asp with fully protected groups), and later, an amidation reaction in liquid phase connects these three parts together. The overall yield of these multiple step synthesis is about 34%. Besides exhibiting excellent solubility, these conjugates of saccharide-amino acids-nucleobase (SAN), like the previously reported conjugates of nucleobase-amino acids-saccharide (NAS) and nucleobase-saccharide-amino acids (NSA), are mammalian cell compatible.
Purine-Based Fluorescent Sensors for Imaging Zinc Ions in HeLa Cells
Pratibha,Singh, Swati,Sivakumar, Sri,Verma, Sandeep
, p. 4202 - 4209 (2017)
We synthesized three chelate-tethered purine ligands, having a Schiff base linkage at the N9 position, which resulted in the dipolar imine-methoxyphenol adenine Schiff base HL1, the 2-aminopurine Schiff base HL2, and the 2,6-diaminopurine Schiff base HL3. These ligands selectively showed enhancement of the fluorescence of the zinc ions. The imine-based compound HL1 chelated with zinc ions to give the discrete dimeric structure 1, a green fluorescent complex, which was again stabilized by purine–purine interactions to give a 1D polymeric structure. The ligands having a 6-amino group, HL1 and HL3, have high quantum yield, which gives higher fluorescence enhancement of the free zinc ions in the HeLa cells. HL1 was localized in the cytoplasm and the nucleoli of the HeLa cells, which was confirmed by an RNase digestion test.
Synthesis and biological evaluation of newly designed phosphonate based bone-seeking agent
Srivastava, Pooja,Tiwari, Anjani K.,Chadha, Nidhi,Chuttani, Krishna,Mishra, Anil K.
, p. 12 - 20 (2013)
A cyclic tetraaza based bifunctional triphosphonate ligand 10-(2-aminoethyl)-1,4,7,10-tetraaza cyclododecane-1,4,7-tris(methylenephosphonic acid) (DO3MP-EA) was synthesized as bone-seeking theranostic agent. The compound was characterized by spectroscopic techniques and labelled with 99mTc with more than 97% purity. Blood clearance of 99mTc labelled compound a quick wash out from the circulation. The compound was excreted mainly via kidneys and accumulation of 99mTc-DO3MP-EA in bone was 9.53 ± 1.06% of injected dose per gram of bone at 1 h. The preliminary CADD analysis confirms the efficacy of DO3MP-EA (G Score -7.005) as better binding agent for osteocalcin (pdb 1Q8H) rather than other known clinical agents. Subsequently stability constant of chelate with Ga(III) was found to be 18.6 which confirms its efficacy as 68Ga labelled PET radiopharmaceutical for bone.
