Ananya Barui

Bio: Ananya Barui is an academic researcher from Indian Institute of Engineering Science and Technology, Shibpur. The author has contributed to research in topics: Tissue engineering & Medicine. The author has an hindex of 14, co-authored 60 publications receiving 593 citations. Previous affiliations of Ananya Barui include Indian Institute of Technology Kharagpur.

ROS generation by reduced graphene oxide (rGO) induced by visible light showing antibacterial activity: comparison with graphene oxide (GO)

Abstract: Reduced graphene oxide (rGO) generates reactive oxygen species (ROS) under visible light in air via a singlet oxygen–superoxide anion radical pathway which readily kills Enterobacter sp. The rGO+ intermediate reacts with a hydroxyl ion to produce graphene oxide (GO) as a coating on the surface of rGO resulting in enhanced fluorescence and a slow down in photo-induced ROS formation. GO is not toxic but on ageing it gets a surface coating of rGO and shows toxicity.

Current Developments in 3D Bioprinting for Tissue and Organ Regeneration–A Review

Abstract: The field of Tissue engineering and regenerative medicine that work towards creating functional tissue-constructs mimicking native tissue for repair and/or replacement of damaged tissues or whole organs have evolved rapidly over the past few decades. However, traditional tissue engineering approaches comprising of scaffolds, growth factors and cells showed limited success in fabrication of complex 3D shapes and in vivo organ regeneration leading to their non-feasibility for clinical applications from a logistical and economical viewpoint. In this regard, 3D bioprinting, which is an extended application of additive manufacturing is now being explored for tissue engineering and regenerative medicine as it involves the top-down approach of building the complex tissue in a layer by layer fashion, thereby producing precise geometries due to controlled nature of matter deposition with the help of anatomically accurate 3D models of the tissue generated by computer graphics. Here, we aim to provide a comprehensive review of the 3D bioprinting technology along with associated 3D bioprinting strategies including ink-jet printing, extrusion printing, stereolithography and laser assisted bioprinting techniques. We then focus on the applications of 3D bioprinting technology on construction of various representative tissue and oragans, including skin, cardiac, bone and cartilage etc. We further attempt to highlight the steps involved in each of those tissues/organs printing and discuss on the associated technological requirements based on the available reports from recent literature. We finally conclude with current challenges with 3D bioprinting technology along with potential solution for future technological advancement of efficient and cost-effective 3D bioprinting methods.

Alginate-honey bioinks with improved cell responses for applications as bioprinted tissue engineered constructs

Abstract: The polysaccharide alginate has received most extensive attention as bioink in bioprinting applications due to its ability to undergo gelation under cell-friendly conditions. However, absence of cell-binding motifs and the erratic degradation of alginate hydrogels have remained their persistent limitations. Honey is a conveniently available natural material, known for its role in wound healing and skin tissue regeneration. However, honey blending to improve biological response of alginate-based bioprinted scaffolds has not been yet reported. In the present work, honey-alginate bioinks were evaluated for their printability property (shape fidelity). It was found that honey blending reduced alginate viscosity, which gradually affected bioprinting fidelity. Therefore, the concentration that provides for acceptable bioprinting along with improvement in cell proliferations is determined. It is concluded that honey blending improves cell response of alginate bioinks and can be a facile approach to obtain bioinks especially for in situ skin tissue engineering applications.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

Role of Reactive Oxygen Species in Cancer Progression: Molecular Mechanisms and Recent Advancements.

Abstract: Reactive oxygen species (ROS) play a pivotal role in biological processes and continuous ROS production in normal cells is controlled by the appropriate regulation between the silver lining of low and high ROS concentration mediated effects. Interestingly, ROS also dynamically influences the tumor microenvironment and is known to initiate cancer angiogenesis, metastasis, and survival at different concentrations. At moderate concentration, ROS activates the cancer cell survival signaling cascade involving mitogen-activated protein kinase/extracellular signal-regulated protein kinases 1/2 (MAPK/ERK1/2), p38, c-Jun N-terminal kinase (JNK), and phosphoinositide-3-kinase/ protein kinase B (PI3K/Akt), which in turn activate the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), matrix metalloproteinases (MMPs), and vascular endothelial growth factor (VEGF). At high concentrations, ROS can cause cancer cell apoptosis. Hence, it critically depends upon the ROS levels, to either augment tumorigenesis or lead to apoptosis. The major issue is targeting the dual actions of ROS effectively with respect to the concentration bias, which needs to be monitored carefully to impede tumor angiogenesis and metastasis for ROS to serve as potential therapeutic targets exogenously/endogenously. Overall, additional research is required to comprehend the potential of ROS as an effective anti-tumor modality and therapeutic target for treating malignancies.

Printability and Shape Fidelity of Bioinks in 3D Bioprinting.

Abstract: Three-dimensional bioprinting uses additive manufacturing techniques for the automated fabrication of hierarchically organized living constructs. The building blocks are often hydrogel-based bioinks, which need to be printed into structures with high shape fidelity to the intended computer-aided design. For optimal cell performance, relatively soft and printable inks are preferred, although these undergo significant deformation during the printing process, which may impair shape fidelity. While the concept of good or poor printability seems rather intuitive, its quantitative definition lacks consensus and depends on multiple rheological and chemical parameters of the ink. This review discusses qualitative and quantitative methodologies to evaluate printability of bioinks for extrusion- and lithography-based bioprinting. The physicochemical parameters influencing shape fidelity are discussed, together with their importance in establishing new models, predictive tools and printing methods that are deemed instrumental for the design of next-generation bioinks, and for reproducible comparison of their structural performance.

Intrinsic oxidative stress in cancer cells: A biochemical basis for therapeutic selectivity using ROS -generating agents

Abstract: PurposeTherapeutic selectivity is one of the most important considerations in cancer chemotherapy. The design of therapeutic strategies to preferentially kill malignant cells while minimizing harmful effects to normal cells depends on our understanding of the biological differences between cancer and normal cells. We have previously demonstrated that certain agents generating reactive oxygen species (ROS) such as 2-methoxyestradiol (2-ME) preferentially kill human leukemia cells without exhibiting significant cytotoxicity in normal lymphocytes. The purpose of the current study was to investigate the biochemical basis for such selective anticancer activity.MethodsFlow cytometric analyses were utilized to measure intracellular O2− levels and apoptosis. MTT assays were used as indicators of cellular viability. Western blot analysis was used to measure the expression of antioxidant enzymes in cancer and normal cells.ResultsMalignant cells in general are more active than normal cells in the production of O2−, are under intrinsic oxidative stress, and thus are more vulnerable to damage by ROS-generating agents. The intrinsic oxidative stress in cancer cells was associated with the upregulation of SOD and catalase protein expression, likely as a mechanism to tolerate increased ROS stress. The increase in SOD and catalase expression was observed both in primary human leukemia cells and in primary ovarian cancer cells. Both malignant cell types were more sensitive to 2-ME than their normal counterparts, as demonstrated by the significant accumulation of O2− and subsequent apoptosis. The administration of ROS scavengers in combination with 2-ME prevented the accumulation of O2− and abrogated apoptosis induction.ConclusionsO2− is an important mediator of 2-ME-induced apoptosis. The increased oxidative stress in cancer cells forces these cells to rely more on antioxidant enzymes such as SOD for O2− elimination, thus making the malignant cells more vulnerable to SOD inhibition than normal cells.

Biofabrication of osteochondral tissue equivalents by printing topologically defined, cell-laden hydrogel scaffolds

Abstract: Osteochondral defects are prone to induce osteoarthritic degenerative changes. Many tissue-engineering approaches that aim to generate osteochondral implants suffer from poor tissue formation and compromised integration. This illustrates the need for further improvement of heterogeneous tissue constructs. Engineering of these structures is expected to profit from strategies addressing the complexity of tissue organization and the simultaneous use of multiple cell types. Moreover, this enables the investigation of the effects of three-dimensional (3D) organization and architecture on tissue function. In the present study, we characterize the use of a 3D fiber deposition (3DF) technique for the fabrication of cell-laden, heterogeneous hydrogel constructs for potential use as osteochondral grafts. Changing fiber spacing or angle of fiber deposition yielded scaffolds of varying porosity and elastic modulus. We encapsulated and printed fluorescently labeled human chondrocytes and osteogenic progenitors in alginate hydrogel yielding scaffolds of 1×2 cm with different parts for both cell types. Cell viability remained high throughout the printing process, and cells remained in their compartment of the printed scaffold for the whole culture period. Moreover, distinctive tissue formation was observed, both in vitro after 3 weeks and in vivo (6 weeks subcutaneously in immunodeficient mice), at different locations within one construct. These results demonstrate the possibility of manufacturing viable centimeter-scaled structured tissues by the 3DF technique, which could potentially be used for the repair of osteochondral defects.