ORCID Profile
0000-0001-5258-0260
Current Organisations
Ruhr University Bochum
,
Universidade Federal de Alagoas
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: American Chemical Society (ACS)
Date: 14-09-2023
Publisher: Wiley
Date: 22-10-2019
Publisher: Wiley
Date: 07-2019
Publisher: Wiley
Date: 11-03-2020
Abstract: Pt II complexes are commonly used to treat cancer. To reduce their side effects and improve their pharmacological properties, Pt IV complexes are being developed as prodrug candidates that are activated by reduction in cancer cells. Concomitantly, Ru II polypyridine complexes have gained much attention as photosensitizers for use in photodynamic therapy due to their attractive characteristics. In this article, a novel Pt IV –Ru II conjugate, which combines cancer activated chemotherapy with PDT, is presented. Upon entering the cancer cell, the Pt IV centre is reduced to Pt II and the axial ligands including the Ru II complex and phenylbutyrate are released. As each component has its in idual targets, the conjugate exerts a multi‐target and multi‐action effect with (photo‐)cytotoxicity values upon irradiation up to 595 nm in the low nanomolar range in various (drug resistant) 2D monolayer cancer cells and 3D multicellular tumour spheroids.
Publisher: Portal de Periodicos UFPB
Date: 31-12-2020
DOI: 10.22478/UFPB.1981-1268.2020V14N4.56558
Abstract: Com base em um argumento socioambiental é relevante compreender que a questão do excesso de água no Vale do Itajaí e no município de Aracaju apresenta um indicador significativo de vulnerabilidade resultante dos deslizamentos, cheias e alagamentos em áreas de ocupação irregular. Objetivou-se discutir a problemática das condições de vulnerabilidades à ocupação urbana nos cenários de Blumenau (SC) e Aracaju (SE), respectivamente, regiões Sul e no Nordeste do Brasil, sob a perspectiva socioambiental. A metodologia contemplou múltiplos procedimentos e técnicas, desde o estudo acerca do Vale do Itajaí que envolve visitas técnicas, mapeamento e levantamento de dados qualitativos, até a pesquisa sobre o litoral de Sergipe que envolveu a avaliação do risco a partir da análise da ocupação da frente litorânea, ambas buscando uma avaliação geoecológica da paisagem, em que foram analisadas a composição, a estruturação, a evolução e a função exercida pelas unidades delimitadas. Os principais resultados apontam para argumentos os quais enfatizam que com o crescente aumento da população urbana nessas áreas, é importante incorporar o conhecimento dos riscos e vulnerabilidades a que os habitantes estão sujeitos. Medidas de mitigação e adaptação a estes riscos que aumentem a resiliência da população são evidentemente necessárias e precisam ser incluídas no planejamento e na gestão das cidades. Conclui-se que estas medidas necessitam reforçar a legitimidade nos processos de governança por meio da participação social.
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D1CB00146A
Abstract: Ruthenium complexes have emerged as a promising class of compounds for use as photosensitizers in photodynamic therapy. Direct conjugation to aptamers enhances their therapeutic usefulness by conveying specificity to Ru-mediated PDT.
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/C9SC05976H
Abstract: This study shows the transformation of a non-phototoxic PDT photosensitizer into an active photosensitizer using an easy, versatile and generalizable one-pot ruthenium-initiated polymerization technique.
Publisher: Springer Science and Business Media LLC
Date: 04-11-2020
Publisher: Wiley
Date: 23-11-2021
Abstract: The global spread of the severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) has called for an urgent need for dedicated antiviral therapeutics. Metal complexes are commonly underrepresented in compound libraries that are used for screening in drug discovery c aigns, however, there is growing evidence for their role in medicinal chemistry. Based on previous results, we have selected more than 100 structurally erse metal complexes for profiling as inhibitors of two relevant SARS‐CoV‐2 replication mechanisms, namely the interaction of the spike (S) protein with the ACE2 receptor and the papain‐like protease PL pro . In addition to many well‐established types of mononuclear experimental metallodrugs, the pool of compounds tested was extended to approved metal‐based therapeutics such as silver sulfadiazine and thiomersal, as well as polyoxometalates (POMs). Among the mononuclear metal complexes, only a small number of active inhibitors of the S/ACE2 interaction was identified, with titanocene dichloride as the only strong inhibitor. However, among the gold and silver containing complexes many turned out to be very potent inhibitors of PL pro activity. Highly promising activity against both targets was noted for many POMs. Selected complexes were evaluated in antiviral SARS‐CoV‐2 assays confirming activity for gold complexes with N‐heterocyclic carbene (NHC) or dithiocarbamato ligands, a silver NHC complex, titanocene dichloride as well as a POM compound. These studies might provide starting points for the design of metal‐based SARS‐CoV‐2 antiviral agents.
Publisher: American Chemical Society (ACS)
Date: 14-03-2020
DOI: 10.1021/JACS.9B13620
Publisher: Wiley
Date: 30-08-2019
Abstract: The use of photodynamic therapy (PDT) to treat cancer has received increasing attention over the last years. However, the clinically used photosensitisers (PSs) have some limitations that include poor aqueous solubility, hepatotoxicity, photobleaching, aggregation, and slow clearance from the body, so the design of new classes of PSs is of great interest. We present the use of bis(dipyrrinato)zinc(II) complexes with exceptionally long lifetimes as efficient PDT PSs. Based on the heavy-atom effect, intersystem crossing of these complexes changes the excited state from singlet to a triplet state, thereby enabling singlet oxygen generation. To overcome the limitation of quenching effects in water and improve water solubility, the lead compound 3 was encapsulated in a polymer matrix. It showed impressive phototoxicity upon irradiation at 500 nm in various monolayer cancer cells as well as 3D multicellular tumour spheroids, without observed dark toxicity.
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0DT01107J
Abstract: A series of new ferrocenyl and ruthenocenyl derivatives of the organic drug albendazole have been prepared and their activity against different helminths and protozoans assessed.
Publisher: American Chemical Society (ACS)
Date: 18-07-2022
Publisher: Elsevier BV
Date: 02-2021
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C8DT02392A
Abstract: A ruthenium( ii ) complex was loaded onto mesoporous silica nanoparticles and the phototherapeutic activity of the materials was tested in cancer cells.
Publisher: American Chemical Society (ACS)
Date: 26-11-2020
Publisher: Wiley
Date: 06-08-2020
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1DT02083H
Abstract: Subtle structural modifications of a ruthenium complex significantly affect its performances as a photosensitizer for photodynamic therapy, including its cellular uptake and its phototoxicity.
Publisher: American Chemical Society (ACS)
Date: 04-09-2019
DOI: 10.1021/ACS.INORGCHEM.9B02019
Abstract: Fluorescence imaging is a powerful tool in biomedical research. It has been frequently used to uncover or better understand physiological mechanisms in disease-related processes such as cancer. The majority of chromophores used for imaging are based on a 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) scaffold. However, their applications are limited due to their poor water solubility as well as poor cancer cell selectivity. To circumvent these drawbacks, we present herein the use of bis(dipyrrinato)zinc(II) complexes. As this class of compounds is associated with a quenching effect of the excited state in water, the lead compound of this study (
Publisher: American Chemical Society (ACS)
Date: 23-10-2017
DOI: 10.1021/ACS.ACCOUNTS.7B00180
Abstract: Photodynamic Therapy (PDT) is an emerging technique to treat certain types of cancer, bacterial, fungal, and viral infections, and skin diseases. In past years, different research groups developed new ruthenium-containing photosensitizers (PSs) with tuned photophysical and biological properties to better fit the requirements of PDT. In this Account, we report and discuss the latest results in this research area, emphasizing particularly our own research. For ex le, inspired by the DNA intercalating complex [Ru(bpy)
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D2SC06675K
Abstract: An iridium( iii ) two-photon photosensitizer was demonstrated to effectively trigger melanoma cell death by a combination of ferroptosis and ICD, and also cause the systemic induction of an immune response.
Publisher: Wiley
Date: 11-03-2020
Abstract: Pt II complexes are commonly used to treat cancer. To reduce their side effects and improve their pharmacological properties, Pt IV complexes are being developed as prodrug candidates that are activated by reduction in cancer cells. Concomitantly, Ru II polypyridine complexes have gained much attention as photosensitizers for use in photodynamic therapy due to their attractive characteristics. In this article, a novel Pt IV –Ru II conjugate, which combines cancer activated chemotherapy with PDT, is presented. Upon entering the cancer cell, the Pt IV centre is reduced to Pt II and the axial ligands including the Ru II complex and phenylbutyrate are released. As each component has its in idual targets, the conjugate exerts a multi‐target and multi‐action effect with (photo‐)cytotoxicity values upon irradiation up to 595 nm in the low nanomolar range in various (drug resistant) 2D monolayer cancer cells and 3D multicellular tumour spheroids.
Publisher: American Chemical Society (ACS)
Date: 16-02-2022
DOI: 10.1021/JACS.1C13137
Abstract: Despite the clinical success of photodynamic therapy (PDT), the application of this medical technique is intrinsically limited by the low oxygen concentrations found in cancer tumors, h ering the production of therapeutically necessary singlet oxygen (
Publisher: American Chemical Society (ACS)
Date: 05-04-2021
Publisher: Elsevier BV
Date: 11-2019
Publisher: Wiley
Date: 11-01-2023
Abstract: An increasing number of novel Ru(II) polypyridyl complexes have been successfully applied as photosensitizers (PSs) for photodynamic therapy (PDT). Despite recent advances in optimized PSs with refined photophysical properties, the lack of tumoral selectivity is often a major hurdle for their clinical development. Here, classical maleimide and versatile NHS‐activated acrylamide strategies were employed to site‐selectively conjugate a promising Ru(II) polypyridyl complex to the N ‐terminally Cys‐modified Bombesin (BBN) targeting unit. Surprisingly, the decreased cell uptake of these novel Ru‐BBN conjugates in cancer cells did not h er the high phototoxic activity of the Ru‐containing bioconjugates and even decreased the toxicity of the constructs in the absence of light irradiation. Overall, although deceiving in terms of selectivity, our new bioconjugates could still be useful for advanced cancer treatment due to their nontoxicity in the dark.
Publisher: Portal de Periodicos UFPB
Date: 31-12-2020
DOI: 10.22478/UFPB.1981-1268.2020V14N4.52548
Abstract: As Áreas de Preservação Permanente (APP) são regulamentadas através da Lei Federal nº 12.651/2012. Essa Lei atua como instrumento regulador no processo de tomada de decisão para minimizar os problemas socioambientais, causados pelas ersas interferências antrópicas. Desta forma, esse artigo teve como objetivo geral analisar as unidades de paisagem em APP urbanas das cidades de Aracaju/SE e Blumenau/SC. Para construção desse estudo, foi elaborada uma análise comparativa entre trechos, de cada município, que apresentaram fortes ações antrópicas, sendo este o critério de escolha. Em Blumenau, utilizou-se como área de abrangência a da microbacia do Ribeirão Fresco e em Aracaju, utilizou-se como área de abrangência a do rio Poxim. Os procedimentos metodológicos desse estudo foram ramificados em 3 etapas: revisão bibliográfica visitas técnicas e sistematização dos dados, utilizando-se técnicas de Geoprocessamento, levantamento fotográfico e análise de documentos. Observou-se que nas duas regiões há problemáticas socioambientais semelhantes, a exemplo da ocupação (construções) em áreas destinadas às APP. Através dessas ocupações, as pressões antrópicas tornaram-se maiores, resultando em problemas como enchentes, deslizamentos de terra, descarte incorreto de resíduos sólidos, entre outros. Por fim, espera-se que, com os resultados apresentados, haja intervenção do poder público, nessas áreas protegidas juridicamente, com a formulação de políticas públicas efetivas, conservando a função socioambiental das APP.
Publisher: American Chemical Society (ACS)
Date: 20-10-2023
Publisher: Springer Science and Business Media LLC
Date: 26-06-2020
DOI: 10.1038/S41467-020-16993-0
Abstract: The use of photodynamic therapy (PDT) against cancer has received increasing attention over recent years. However, the application of the currently approved photosensitizers (PSs) is limited by their poor aqueous solubility, aggregation, photobleaching and slow clearance from the body. To overcome these limitations, there is a need for the development of new classes of PSs with ruthenium(II) polypyridine complexes currently gaining momentum. However, these compounds generally lack significant absorption in the biological spectral window, limiting their application to treat deep-seated or large tumors. To overcome this drawback, ruthenium(II) polypyridine complexes designed in silico with ( E , E ′)-4,4′-bisstyryl-2,2′-bipyridine ligands show impressive 1- and 2-Photon absorption up to a magnitude higher than the ones published so far. While nontoxic in the dark, these compounds are phototoxic in various 2D monolayer cells, 3D multicellular tumor spheroids and are able to eradicate a multiresistant tumor inside a mouse model upon clinically relevant 1-Photon and 2-Photon excitation.
Publisher: Wiley
Date: 17-11-2020
Publisher: Wiley
Date: 15-08-2019
Publisher: Wiley
Date: 30-09-2019
Abstract: Cancer is currently one of the deadliest diseases worldwide. Based on the high incidence of this disease, the side effects associated with current chemotherapies and the appearance of drug resistance, considerable efforts have been directed towards the development of new anticancer drugs with new modes of action. Metal-based compounds are particularly attractive candidates due to their metabolic mechanisms, which differ substantially from those of organic drugs. Of special interest in this context are organometallic ruthenium(II) complexes of the type [Ru(η
Publisher: Wiley
Date: 30-08-2019
Publisher: MDPI AG
Date: 07-01-2019
DOI: 10.3390/INORGANICS7010004
Abstract: Cancer is known to be one of the major causes of death nowadays. Among others, chemotherapy with cisplatin is a commonly used treatment. Although widely employed, cisplatin is known to cause severe side effects, such as nerve and kidney damage, nausea, vomiting, and bone marrow suppression. Most importantly, a number of cancer tumors are acquiring resistance to cisplatin, limiting its clinical use. There is therefore a need for the discovery of novel anticancer agents. Complementary to chemotherapy, Photodynamic Therapy (PDT) has expanded the range of treatment opportunities of numerous kinds of cancer. Nonetheless, the currently approved PDT photosensitizers (PSs) suffer from major drawbacks, which include poor water solubility or photobleaching, in addition to a slow clearance from the body that causes photosensitivity. Due to these limitations, there is a need for the development of new PDT PSs. To overcome these problems, a lot of research groups around the world are currently focusing their attention towards the development of new metal complexes as PDT PSs. However, most synthesized compounds reported so far show limited use due to their poor absorption in the phototherapeutic window. Herein, we report on the preparation and characterization of three Fe(II) polypyridine complexes (4–6) and evaluate their potential as both anticancer agents and PDT PSs. Very importantly, these compounds are stable in human plasma, photostable upon continuous LED irradiation, and absorb in the red region of the spectrum. We could demonstrate that through additional sulfonic acid groups on the polypyridine ligand being used (bphen: 4,7-diphenyl-1,10-phenanthroline), the water solubility of the complexes could be highly improved, whereas the photophysical properties did not significantly change. One of these complexes (4) shows interesting toxicity, with IC50 values in the low micromolar range in the dark as well as some phototoxicity upon irradiation at 480 and 540 nm against RPE-1 and HeLa cells.
Publisher: American Chemical Society (ACS)
Date: 13-04-2021
Abstract: Cancer is the leading cause of death in the developed world. In the last few decades, photodynamic therapy (PDT) has augmented the number of medical techniques to treat this disease in the clinics. As the pharmacological active species to kill cancer cells are only generated upon light irradiation, PDT is associated with an intrinsic first level of selectivity. However, since PDT agents also accumulate in the surrounding, healthy tissue and since it is practically very challenging to only expose the tumor site to light, some side effects can be observed. Consequently, there is a need for a selective drug delivery system, which would give a second level of selectivity. In this work, a dual tumor targeting approach is presented based on mesoporous silica nanoparticles, which act by the enhanced permeability and retention effect, and the conjugation to folic acid, which acts as a targeting moiety for folate receptor-overexpressed cancer cells. The conjugates were found to be nontoxic in noncancerous human normal lung fibroblast cells while showing a phototoxic effect upon irradiation at 480 or 540 nm in the low nanomolar range in folate receptor overexpressing cancerous human ovarian carcinoma cells, demonstrating their potential for cancer targeted treatment.
Location: United States of America
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Johannes Karges.