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Diapause exhibited by embryos of Artemia franciscana is accompanied by severe arrest of respiration. A large fraction of this depression is attributable to downregulation of trehalose catabolism that ultimately restricts fuel to mitochondria. This study now extends knowledge on the mechanism by revealing metabolic depression is heightened by inhibitions within mitochondria. Compared with that in embryo lysates during post-diapause, oxidative phosphorylation (OXPHOS) capacity P is depressed during diapause when either NADH-linked substrates (pyruvate and malate) for electron transfer (electron transfer capacity, E) through respiratory Complex I or the Complex II substrate succinate are used. When pyruvate, malate and succinate were combined, respiratory inhibition by the phosphorylation system in diapause lysates was discovered as judged by P/E flux control ratios (two-way ANOVA; F1,24=38.78; P<0.0001). Inhibition was eliminated as the diapause extract was diluted (significant interaction term; F2,24=9.866; P=0.0007), consistent with the presence of a diffusible inhibitor. One candidate is long-chain acyl-CoA esters known to inhibit the adenine nucleotide translocator. Addition of oleoyl-CoA to post-diapause lysates markedly decreased the P/E ratio to 0.40±0.07 (mean±s.d.; P=0.002) compared with 0.79±0.11 without oleoyl-CoA. Oleoyl-CoA inhibits the phosphorylation system and may be responsible for the depressed P/E in lysates from diapause embryos. With isolated mitochondria, depression of P/E by oleoyl-CoA was fully reversed by addition of l-carnitine (control versus recovery with l-carnitine, P=0.338), which facilitates oleoyl-CoA transport into the matrix and elimination by ß-oxidation. In conclusion, severe metabolic arrest during diapause promoted by restricting glycolytic carbon to mitochondria is reinforced by depression of OXPHOS capacity and the phosphorylation system.
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Diapausa , Extremófilos , Animais , Fosforilação Oxidativa , Artemia/fisiologia , Malatos , Piruvatos , Succinatos , CarnitinaRESUMO
This review describes the design strategies used for the synthesis of various tetracyanobutadiene bridged donor-acceptor molecular architectures by a click type [2+2] cycloaddition-retroelectrocyclization (CA-RE) reaction sequence. The photophysical and electrochemical properties of the tetracyanobutadiene bridged molecular architectures based on various moieties including diketopyrrolopyrrole, isoindigo, benzothiadiazole, pyrene, pyrazabole, truxene, boron dipyrromethene (BODIPY), phenothiazine, triphenylamine, thiazole and bisthiazole are summarized. Further, we discuss some important applications of the tetracyanobutadiene bridged derivatives in dye sensitized solar cells, bulk heterojunction solar cells and photothermal cancer therapy.
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Room temperature phosphorescence (RTP) in purely organic materials is an uncommon phenomenon of emission, which can be characterized by a long persistent luminescence after removal of the excitation source. In the recent years, RTP organic materials have received a considerable attention due to their high application potential in various advancing technologies, ranging from optoelectronic to biomedical applications. In parallel, many progresses have been achieved on the rationalization of this process and led to the emergence of innovative strategies aiming to achieve highest performances both in terms of phosphorescence efficiency and lifetime. While the topic is still on an ascendant development, the generation of circularly polarized phosphorescent (CPP) emission from purely organic molecules is by far much less explored and remains an impressive challenge. Still, the perspective of CPP materials appears as an interesting opportunity to answer several comprehensives issues existing in the field. In this article, we define, in a straightforward way, basic principles and key notions for the generation of RTP and CP luminescence (CPL) guiding the design toward CPP materials. After this brief insight, recent advances in the field of chiral organic RTP materials are discussed with an emphasis on their CP-RTP properties. Based on this development, the conclusion drawn allows establishing the next challenges and future opportunities standing in the field.
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Intervalence charge transfer (IVCT), a phenomenon observed in molecular systems comprised of two redox centers differing in oxidation states by one unit, is reported in a novel, newly synthesized, multi-modular donor-acceptor system comprised of central bis(thienyl)diketopyrrolopyrrole (TDPP) hosting two phenothiazine-tetracyanobutadiene (PTZ-TCBD) entities on the opposite sides. One-electron reduction of TCBD promoted electron exchange between the two TCBD resulting in IVCT transition in the near-infrared region. The stabilization energy, -ΔGcom and comproportionation equilibrium constant, Kcom calculated from peak potentials of the split reduction waves were found to be 1.06×104 â J mol-1 , and 72.3â M-1 , respectively. Further, the IVCT transition was also witnessed during the process of thermodynamically feasible electron transfer upon excitation of the TDPP entity in the system, and served as a diagnostic marker to characterize the electron transfer product. Subsequent transient absorption spectral studies and data analysis by Global and Target analyses revealed occurrence of ultrafast charge separation (kcs ≈1010 â s-1 ) owing to the close proximity and good communication between the entities of the multi-modular donor-acceptor system. The role of central TDPP in promoting IVCT is borne out from the present investigation.
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The significance of multiple number of donor-acceptor entities on a central electron donor in a star-shaped molecular system in improving light energy harvesting ability is reported. For this, donor-acceptor-donor type conjugates comprised up to three entities ferrocenyl (Fc)-diketopyrrolopyrrole (DPP) onto a central triphenylamine (TPA), (4-6) by the Pd-catalyzed Sonogashira cross-coupling reactions have been newly synthesized and characterized. Donor-acceptor conjugates possessing diketopyrrolopyrrole (1 to 3 entities) onto the central triphenylamine, (1-3) served as reference dyads while monomeric DPP and Fc-DPP served as control compounds. Both DPP and Fc-DPP carrying conjugates exhibited red-shifted absorption compared to their respective control compounds revealing existence of ground state interactions. Furthermore, DPP fluorescence in 4-6 was found to be quantitatively quenched while for 1-3, this property varied between 73-65 % suggesting occurrence moderate amounts of excited state events. The electrochemical investigations exhibited an additional low potential oxidation in the case of Fc-DPP-TPA based derivatives (4-6) owing to the presence of ferrocene unit(s). This was in addition to DPP and TPA redox peaks. Using spectral, electrochemical and computational studies, Gibbs free-energy calculations were performed to visualize excited state charge separation (ΔGCS ) in these donor-acceptor conjugates as a function of different number of Fc-DPP entities. Formation of Fc+ -DPP.- -TPA charge separated states (CSS) in the case of 4-6 was evident. Using spectroelectrochemical studies, spectrum of CSS was deduced. Finally, femtosecond transient absorption spectral studies were performed to gather information on excited state charge separation. Increasing the number of Fc-DPP entities in 4-6 improved charge separation rates. Surprisingly, lifetime of the charge separated state, Fc+ -DPP.- -TPA was found to persist longer with an increase in the number of Fc-DPP entities in 4-6 as compared to Fc-DPP-control and simple DPP derived donor-acceptor conjugates in literature. This unprecedented result has been attributed to subtle changes in ΔGCS and ΔGCR and the associated electron coupling between different entities.
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After first report on diketopyrrolopyrrole in 1974 by Farnum etâ al., a wide variety of its derivatives have been reported for material and biological applications. In this review we discuss various design strategies used for the synthesis of metal functionalized diketopyrrolopyrrole derivatives along with their photophysical and electrochemical studies with respect to material and biological applications. Some exciting applications of ferrocenyl functionalized diketopyrrolopyrrole derivatives such as non-linear optics, organic solar cells and photothermal therapy were recently reported, which are also discussed in this review.
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Push-pull systems comprising of triphenylamine-tetracyanobutadiene (TPA-TCBD), a high-energy charge-transfer species, are linked to a near-IR sensitizer, azaBODIPY, for promoting excited-state CS. These systems revealed panchromatic absorption owing to intramolecular CT and near-IR absorbing azaBODIPY. Using electrochemical and computational studies, energy levels were established to visualize excited state events. Fs-TA studies were performed to monitor excited state CT events. From target analysis, the effect of solvent polarity, number of linked CT entities, and excitation wavelength dependence in governing the lifetime of CS states was established. Electron exchange between two TPA-TCBD entities in 3 seem to prolong lifetime of the CS state. We have been successful in demonstrating efficient CS upon both high-energy CT and low-energy near-IR excitations, signifying importance of these push-pull systems for optoelectronic applications operating in the wide optical window.
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In preparation for the onset of environmental challenges like overwintering, food limitation, anoxia, or water stress, many invertebrates and certain killifish enter diapause. Diapause is a developmentally-programed dormancy characterized by suppression of development and metabolism. For embryos of Artemia franciscana (brine shrimp), the metabolic arrest is profound. These gastrula-stage embryos depress oxidative metabolism by ~99% during diapause and survive years of severe desiccation in a state termed anhydrobiosis. Trehalose is the sole fuel source for this developmental stage. Mitochondrial function during diapause is downregulated primarily by restricting substrate supply, as a result of inhibiting key enzymes of carbohydrate metabolism. Because proton conductance across the inner membrane is not decreased during diapause, the inference is that membrane potential must be compromised. In the absence of any intervention, the possibility exists that the F1 Fo ATP synthase and the adenine nucleotide translocator may reverse, leading to wholesale hydrolysis of cellular ATP. Studies with anhydrobiotes like A. franciscana are revealing multiple traits useful for improving desiccation tolerance that include the expression and accumulation late embryogenesis abundant (LEA) proteins and trehalose. LEA proteins are intrinsically disordered in aqueous solution but gain secondary structure (predominantly α-helix) as water is removed. These protective agents stabilize biological structures including lipid bilayers and mitochondria during severe water stress. © 2018 IUBMB Life, 70(12):1251-1259, 2018.
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Diapausa/fisiologia , Desenvolvimento Embrionário/genética , Metabolismo Energético/genética , Mitocôndrias/metabolismo , Adaptação Fisiológica/genética , Animais , Artemia , Desidratação/genética , Desidratação/metabolismo , Diapausa/genética , Embrião não Mamífero , Fundulidae/metabolismo , Mitocôndrias/genética , Trealose/genéticaRESUMO
Organic solar cells (OSCs) have gained attention of the scientific community from the last decade and are now considered as one of the most important source for low-cost power production. The recent rapid progress in non-fullerene acceptors in BHJ indicates that they have potential to compete with fullerene-based BHJ OSCs. The present review addressed the systematic comparison among various acceptors (diketopyrrolopyrrole (DPP), benzothiadiazole (BTD) and perylenediimide (PDI) based acceptors) in order to design and improve the performance of small molecules based non-fullerene acceptors. This review focuses on the performance of small molecule non-fullerene acceptors based on DPP, BTD and PDI for OSCs with respect to the change in molecular structures, energy levels, and PCE. A systematic comparison on the effect of molecular architecture, side chains on their performance is provided with the intention of evaluating the challenge to make highly efficient acceptors for the next generation organic photovoltaics.
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A symmetrical D-π-A-π-D type small molecule consisting of thiophene flanked diketopyrrolopyrrole (DPP) as a core and an end capping ferrocene donor linked by an ethynyl bridge, denoted as Fc-DPP-Fc, was synthesized and its optical, thermal and electrochemical properties were investigated in order to explore its potential applicability as a donor for solution processed bulk heterojunction solar cells. The photophysical and electrochemical properties of this small molecule showed strong charge transfer interaction between the ferrocene donor and the DPP acceptor, and it is found to be suitable as a small molecule donor along with PC71BM as an electron acceptor for solution processed bulk heterojunction organic solar cells (OSCs). Although the open circuit voltage (Voc) of the OSC based on as cast Fc-DPP-Fc : PC71BM (1 : 2 weight ratio) from a THF solvent is quite high (0.98 V), it showed an overall power conversion efficiency (PCE) of 2.55% with low values of short circuit current (Jsc) and fill factor (FF) of 6.35 mA cm-2 and 0.41, respectively. After using a solvent additive (SA), i.e. 3 v% DIO/THF solution for film deposition, the resultant OSC showed an improved overall PCE of 4.83% and it further improved up to 6.44%. The improvement in the PCE value is mainly attributed to the enhancement in Jsc and FF, resulting from the increased light harvesting efficiency, balanced charge transport and favorable nanoscale morphology of the active layer, induced by SA and TSA.
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We report two acetylene-bridged small molecules DPP5 and DPP6 with low HOMO-LUMO gaps as donors along with PC71BM as an acceptor for the fabrication of solution-processed bulk heterojunction solar cells. After the optimization, i.e. weight ratio of donor to acceptor and surface treatment of the active layer, we achieved overall power conversion efficiencies up to 4.65% (Jsc = 8.19 mA cm(-2), Voc = 0.98 V and FF = 0.58) and 5.73% (Jsc = 9.58 mA cm(-2), Voc = 0.98 V and FF = 0.61), for DPP5:PC71BM and DPP6:PC71BM respectively, which are superior to those for the devices based on as-cast active layers. The significant change in the power conversion efficiency is attributed to the improvement in nanoscale morphology, balanced charge transport and charge collection efficiency, induced through the surface treatment.
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Two organic small molecules based on diketopyrrolopyrrole (DPP) units having a D-A-D-π-D-A-D structure denoted as and were synthesized. Their optical and electrochemical properties relevant to organic solar cells were investigated. The wider optical absorption coverage from 450-800 nm, the highest occupied molecular orbital (HOMO) (-5.23 eV and -5.34 eV for and , respectively) and the lowest unoccupied molecular orbital (LUMO) (-3.47 and -3.45 eV for and , respectively) make these small molecules suitable as donors for bulk heterojunction organic solar cells. The bulk heterojunction (BHJ) organic solar cells based on an active layer consists of a blend of these small molecules as donors and PC71BM as an acceptor with an optimized weight ratio of 1 : 2 cast from chloroform (CF) showed overall power conversion efficiencies (PCEs) of 1.98% (with Jsc = 5.38 mA cm(-2), Voc = 0.84 V and FF = 0.42) and 1.85% (with Jsc = 4.56 mA cm(-2), Voc = 0.96 V and FF = 0.42) for and respectively. The relatively high Voc value based on the based device has been attributed to the deeper HOMO of compared to . The optimized : PC71BM (1 : 2) and : PC71BM (1 : 2) active layers were subjected to two step annealing (TSA), i.e. thermal annealing and subsequent solvent vapor annealing and the corresponding BHJ organic solar cells showed a PCE of 5.28% (Jsc = 11.53 mA cm(-2), Voc = 0.79 V and FF = 0.58) and 5.52% (Jsc = 10.84 mA cm(-2), Voc = 0.91 V and FF = 0.56), respectively. The enhancement in PCE is mainly due to the improvement in Jsc and FF, related to light absorption in an active layer, a better nanoscale morphology, and an increase in the crystalline nature of the active layer and balanced charge transport, induced by the TSA treatment.
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Organic dyes that absorb light in the visible to near-infrared region have garnered significant interest, owing to their extensive utility in organic photovoltaics and various biomedical applications. Aza-boron-dipyrromethene (Aza-BODIPY) dyes are a class of chromophores with impressive photophysical properties such as tunable absorption from the visible region towards near infrared (NIR) region, high molar absorptivity, and fluorescence quantum yield. In this review, we discuss the developments in the aza-BODIPYs, related to their synthetic routes, photophysical properties and their applications. Their design strategies, modifications in chemical structures, mode/position of attachment, and their impact on photo-physical properties are reviewed. The potential applications of aza-BODIPY derivatives such as organic solar cells, photodynamic therapy, boron-neutron capture therapy, fluorescence sensors, photo-redox catalysis, photoacoustic probes and optoelectronic devices are explained.
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Capturing circulating tumor cells (CTCs) from the peripheral blood of cancer patients, where they are disseminated among billions of other blood cells, is one of the most daunting challenge. We report OncoDiscover®, a multicomponent nano-system consisting of iron oxide (Fe3O4) nanoparticles (NPs), polyamidoamine generation 4 dendrimers (PAMAM-G4-NH2), graphene oxide (GO) sheets and an anti-epithelial cell adhesion molecule (anti-EpCAM) antibody (Fe-GSH-PAMAM-GO-EpCAM) for the selective and precise capture of CTCs. We further evaluated this system for therapeutically important oncotargets, exemplifying overexpression of the programmed death ligand 1 (PD-L1) as a functional assay on CTCs in cancer patients. We retrospectively evaluated 134 cancer patients for the presence of CTCs and 113 (84%) showed the presence of CTCs. About 62 (55%) of the CTC +ve patients showed CTCs with PD-L1 expression. The personalized cancer detection demonstrated by the OncoDiscover® CTC analysis tool is highly relevant for cancer monitoring and treatment outcomes.
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Micro and nanobots (MNBs) are unprecedented in their ability to be chemically tuned for autonomous tasks with enhanced targeting and functionality while maintaining their mobility. A myriad of chemical modifications involving a large variety of advanced materials have been demonstrated to be effective in the design of MNBs. Furthermore, they can be controlled for their autonomous motion, and their ability to carry chemical or biological payloads. In addition, MNBs can be modified to achieve targetability with specificity for biological implications. MNBs by virtue of their chemical compositions may be limited by their biocompatibility, tissue accumulation, poor biodegradability and toxicity. This review presents a note on artificial intelligence materials (AIMs), their importance, and the dimensional scales at which intrinsic autonomy can be achieved for diverse utility. We briefly discuss the evolution of such systems with a focus on their advancements in nanomedicine. We highlight MNBs covering their contemporary traits and the emergence of a few start-ups in specific areas. Furthermore, we showcase various examples, demonstrating that chemical tunability is an attractive primary approach for designing MNBs with immense capabilities both in biology and chemistry. Finally, we cover biosafety and ethical considerations in designing MNBs in the era of artificial intelligence for varied applications.
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Inteligência Artificial , Nanomedicina , Movimento (Física) , MicrobolhasRESUMO
Designing nano-substrates (NS) that support three-dimensional (3D) cell growth using physico-chemical interventions mimicking the cellular microenvironment is highly challenging. Here we report NS that assist 3D cell development (3D NS) using multi-components on a glass substrate (2D GS), which mimics the ex vivo tissue microenvironment and promotes 3D cell growth superior to conventional 2D cell culturing methodologies. 3D NS were chemically fabricated by linking the combination of advanced materials imparting different physico-chemical traits, for example, multiwalled carbon nanotubes (CNT), graphene (G), bovine serum albumin (BSA), and iron oxide magnetic nanoparticles (MNP). We compared cell-substrate interactions resulting in cellular morphological changes, influence on the cell circularity index (CI), nuclear-cytoplasmic ratios (N/C), and nuclear compression or derangements using human colorectal carcinoma cells (HCT116) and cervical cancer (HeLa) cells. We observed the increase in N/C, extended on the 3D NS micro-environment as indicative of cellular adaptation and the transformation. HCT116 and HeLa cells on 2D GS showed an N/C ratio <0.3, and 3D NS cultured cells exhibited a higher N/C ratio (>0.5). The most significant increase in the ratio, relative to arrested cell spreading, was observed with G-3D NS. Furthermore, 3D NS were evaluated for the cell viability differentiations using the anticancer drug doxorubicin (Dox). The drug-treated cells on 3D NS demonstrated far-displaced N/C ratios compared to 2D GS. In conclusion, 3D NS systems implicate an 'in vitro to in vivo' relevance for the outcome in cell biology, cell proliferation and migration, and in anticancer drug efficacy evaluation.
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Antineoplásicos , Nanotubos de Carbono , Antineoplásicos/farmacologia , Proliferação de Células , Doxorrubicina/farmacologia , Células HeLa , HumanosRESUMO
Correction for 'Designing 3D-nanosubstrates mimicking biological cell growth: pitfalls of using 2D substrates in the evaluation of anticancer efficiency' by Ashwini Patil et al., Nanoscale, 2021, 13, 17473-17485, DOI: 10.1039/d1nr03816h.
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Nanosized robots with self-propelling and navigating capabilities have become an exciting field of research, attributable to their autonomous motion and specific biomolecular interaction ability for bio-analysis and diagnosis. Here, we report magnesium (Mg)-Fe3O4-based Magneto-Fluorescent Nanorobot ("MFN") that can self-propel in blood without any other additives and can selectively and rapidly isolate cancer cells. The nanobots viz; Mg-Fe3O4-GSH-G4-Cy5-Tf and Mg-Fe3O4-GSH-G4-Cy5-Ab have been designed and synthesized by simple surface modifications and conjugation chemistry to assemble multiple components viz; (i) EpCAM antibody/transferrin, (ii) cyanine 5 NHS (Cy5) dye, (iii) fourth generation (G4) dendrimers for multiple conjugation and (iv) glutathione (GSH) by chemical conjugation onto one side of Mg nanoparticle. The nanobots propelled efficiently not only in simulated biological media, but also in blood samples. With continuous motion upon exposure to water and the presence of Fe3O4 shell on Mg nanoparticle for magnetic guidance, the nanobot offers major improvements in sensitivity, efficiency and speed by greatly enhancing capture of cancer cells. The nanobots showed excellent cancer cell capture efficiency of almost 100% both in serum and whole blood, especially with MCF7 breast cancer cells.
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Control of the sub-cellular localization of nanoparticles (NPs) with enhanced drug-loading capacity, employing graphene oxide (GO), iron oxide (Fe3O4) NPs and sandwiched deoxyribonucleic acid (DNA) bearing intercalated anticancer drug doxorubicin (DOX) has been investigated in this work. The nanosystems G-DNA-DOX-Fe3O4 and Fe3O4-DNA-DOX differentially influence serum protein binding and deliver DOX to lysosomal compartments of cervical cancer (HeLa) cells with enhanced retention. Stern-Volmer plots describing BSA adsorption on the nanosystems demonstrated the quenching constants, K sv for G-DNA-DOX-Fe3O4 and Fe3O4-DNA-DOX (0.025 mL µg-1 and 0.0103 mL µg-1 respectively). Nuclear DOX intensity, measured at 24 h, was â¼2.0 fold higher for Fe3O4-DNA-DOX in HeLa cells. Parallelly, the cytosol displayed â¼2.2 fold higher DOX intensity for Fe3O4-DNA-DOX compared to G-DNA-DOX-Fe3O4. Fe3O4-DNA-DOX was more efficacious in the cytotoxic effect than G-DNA-DOX-Fe3O4 (viability of treated cells: 33% and 49% respectively). The DNA:nanosystems demonstrated superior cytotoxicity compared to mole-equivalent free DOX administration. The results implicate DNA:DOX NPs in influencing the cellular uptake mechanism and were critically subject to cellular localization. Furthermore, cell morphology analysis evidenced maximum deformation attributed to free-DOX with 34% increased cell roundness, 63% decreased cell area and â¼1.9 times increased nuclear-to-cytoplasmic (N/C) ratio after 24 h. In the case of Fe3O4-DNA-DOX, the N/C ratio increased 1.2 times and a maximum â¼37% decrease in NSA was noted suggesting involvement of non-canonical cytotoxic pathways. In conclusion, the study makes a case for designing nanosystems with controlled and regulated sub-cellular localization to potentially exploit secondary cytotoxic pathways, in addition to optimized drug-loading for enhanced anticancer efficacy and reduced adverse effects.
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Here we report nanocarrier-anticancer drug conjugates culpable for cellular deformations, critically evidenced through image-based analysis as a measure of karyoplasmic ratio (KR) and nuclear surface area (NSA). Multiwalled carbon nanotubes (MWCNTs) were coordinated additionally with Fe3O4 nanoparticles (NPs) to evaluate the symbiotic influence, and further conjugated to Dox for evaluating the cellular kinetics and for measuring cell deformations. Cellular entry kinetics of the CNT (CNT-Dox and CNT-Cys-Fe3O4-Dox) nanocarriers and their efficiency in nuclear localization were evaluated using cervical cancer (HeLa) cells. Of note, the Dox-bound nanocarriers showed significantly enhanced cell toxicity over the free form of the drug. CNT-Dox and CNT-Cys-Fe3O4-Dox influx occurred within 4 hours, while maximum cellular retention of Dox was observed for CNT-Dox at 24 h. However, the highest KR (â¼0.51) was observed for CNT-Dox within 8 hours indicating similar cellular deformations using nanocarrier anticancer drug-conjugates to that of free Dox (KR â¼0.50) at 4 hours. In addition, we observed increased NSA at 4 h in Dox treatment whereas in the case of the Dox conjugated nanocarrier, increased NSA was noted at 8 h treatment. At 8 h exposure of HeLa cells with Dox conjugates, we observed that the cells fall into distinct regions of the morphospace with respect to KR and NSA. Conclusively, nano delivery systems considered for clinical and biomedical translations must take into account the possible negative influences imparting higher cellular deformations and secondary adverse effects over the free form of the drug.