Browsing by Author "Divakar Singh"

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A Layer-by-Layer Polycaprolactone/Chitosan-Based Biomimetic Hybrid Nanofibroporous Scaffold for Enhanced Skin Tissue Regeneration: Integrating Solution Blow Spinning and Freeze Casting Techniques
(American Chemical Society, 2025) Divakar Singh; None Darshna; Pradeep Kumar Srivastava
Nanofibers, with their high surface area-to-volume ratio, elasticity, and mechanical strength, significantly enhance scaffold structures for skin tissue engineering. The present study introduces a unique method of combining solution blow spinning (SBS) and freeze casting to fabricate biomimetic hybrid nanofibroporous scaffolds (BHNS) using polycaprolactone (PCL) and chitosan (CH). The developed scaffolds mimic the fibrous porous natural extracellular matrix (ECM) architecture, promoting cell adhesion, proliferation, and matrix deposition. The combined SBS and freeze-casting processes resulted in scaffolds with high porosity and optimal mechanical strength, crucial for effective skin regeneration. Scanning electron microscopy (SEM) confirmed the uniform, nonwoven, and beadless architecture of the PCL fibers and the fibroporous nature of the PCL/CH scaffolds. The scaffolds exhibited excellent swelling behavior, controlled degradation rates, and enhanced mechanical properties. In vitro cell studies demonstrated scaffold cell-supportive properties in terms of cell attachment, proliferation, and migration. This innovative layer-by-layer fabrication technique, integrating nanofibers with freeze-cast scaffolds, represents a significant advancement in skin tissue engineering, promising improved outcomes in wound healing and regenerative medicine. © 2024 American Chemical Society.
Analyzing gene expression through real time PCR while neo-tissue regeneration using developed tissue constructs
(Bentham Science Publishers, 2020) Divakar Singh; Tarun Minocha; Satyavrat Tripathi; Rupika Sinha; Shubhankar Anand; Hareram Birla; Vivek Kumar Pandey; Arun Rawat; Smita Gupta; Sanjeev Kumar Yadav; Pawan Kumar Dubey; Pradeep Srivastava
Real-time PCR offers a wide area of application to analyze the role of gene activity in various biological aspects at the molecular level with higher specificity, sensitivity and the potential to troubleshoot with post-PCR processing and difficulties. With the recent advancement in the development of functional tissue graft for the regeneration of damaged/diseased tissue, it is effective to analyze the cell behaviour and differentiation over tissue construct toward specific lineage through analyzing the expression of an array of specific genes. With the ability to collect data in the exponential phase, the application of Real-Time PCR has been expanded into various fields such as tissue engineering ranging from absolute quantification of gene expression to determine neo-tissue regeneration and its maturation. In addition to its usage as a research tool, numerous advancements in molecular diagnostics have been achieved, including microbial quantification, determination of gene dose and cancer research. Also, in order to consistently quantify mRNA levels, Northern blotting and in situ hybridization (ISH) methods are less preferred due to low sensitivity, poor precision in detecting gene expression at a low level. An amplification step is thus frequently required to quantify mRNA amounts from engineered tissues of limited size. When analyzing tissue-engineered constructs or studying biomaterials-cells interactions, it is pertinent to quantify the performance of such constructs in terms of extracellular matrix formation while in vitro and in vivo examination, provide clues regarding the performance of various tissue constructs at the molecular level. In this chapter, our focus is on Basics of qPCR, an overview of technical aspects of Real-time PCR; recent Protocol used in the lab, primer designing, detection methods and troubleshooting of the experimental problems. © 2020, Bentham eBooks imprint. All rights reserved.
Flavonoids as Promising Neuroprotectants and Their Therapeutic Potential against Alzheimer's Disease
(Hindawi Limited, 2022) Tarun Minocha; Hareram Birla; Ahmad A. Obaid; Vipin Rai; P. Sushma; Chandan Shivamallu; Mahmoud Moustafa; Mohammed Al-Shehri; Ahmed Al-Emam; Maria A. Tikhonova; Sanjeev Kumar Yadav; Burkhard Poeggeler; Divakar Singh; Sandeep Kumar Singh
Alzheimer's disease (AD) is one of the serious and progressive neurodegenerative disorders in the elderly worldwide. Various genetic, environmental, and lifestyle factors are associated with its pathogenesis that affect neuronal cells to degenerate over the period of time. AD is characterized by cognitive dysfunctions, behavioural disability, and psychological impairments due to the accumulation of amyloid beta (Aβ) peptides and neurofibrillary tangles (NFT). Several research reports have shown that flavonoids are the polyphenolic compounds that significantly improve cognitive functions and inhibit or delay the amyloid beta aggregation or NFT formation in AD. Current research has uncovered that dietary use of flavonoid-rich food sources essentially increases intellectual abilities and postpones or hinders the senescence cycle and related neurodegenerative problems including AD. During AD pathogenesis, multiple signalling pathways are involved and to target a single pathway may relieve the symptoms but not provides the permanent cure. Flavonoids communicate with different signalling pathways and adjust their activities, accordingly prompting valuable neuroprotective impacts. Flavonoids likewise hamper the movement of obsessive indications of neurodegenerative disorders by hindering neuronal apoptosis incited by neurotoxic substances. In this short review, we briefly discussed about the classification of flavonoids and their neuroprotective properties that could be used as a potential source for the treatment of AD. In this review, we also highlight the structural features of flavonoids, their beneficial roles in human health, and significance in plants as well as their microbial production. © 2022 Tarun Minocha et al.
In vitro and in vivo assessment of curcumin-quercetin loaded multi-layered 3D-nanofibroporous matrix prepared by solution blow-spinning for full-thickness burn wound healing
(Elsevier B.V., 2024) Soumya Katiyar; Divakar Singh; Abhay Dev Tripathi; Avinash Kumar Chaurasia; Ritika K. Singh; Pradeep K. Srivastava; Abha Mishra
Burn wounds (BWs) cause impairment of native skin tissue and may cause significant microbial infections that demand immediate care. Curcumin (Cur) and quercetin (Que) exhibit antimicrobial, hemocompatibility, ROS-scavenging, and anti-inflammatory properties. However, its instability, water insolubility, and low biological fluid absorption render it challenging to sustain local Cur and Que doses at the wound site. Therefore, to combat these limitations, we employed blow-spinning and freeze-drying to develop a multi-layered, Cur/Que-loaded gelatin/chitosan/PCL (GCP-Q/C) nanofibroporous (NFP) matrix. Morphological analysis of the NFP-matrix using SEM revealed a well-formed multi-layered structure. The FTIR and XRD plots demonstrated dual-bioactive incorporation and scaffold polymer interaction. Additionally, the GCP-Q/C matrix displayed high porosity (82.7 ± 2.07 %), adequate pore size (∼121 μm), enhanced water-uptake ability (∼675 % within 24 h), and satisfactory biodegradation. The scaffolds with bioactives had a long-term release, increased antioxidant activity, and were more effective against gram-positive (S. aureus) and gram-negative (E. coli) bacteria than the unloaded scaffolds. The in vitro findings of GCP-Q/C scaffolds showed promoted L929 cell growth and hemocompatibility. Additionally, an in vivo full-thickness BW investigation found that an implanted GCP-Q/C matrix stimulates rapid recuperation and tissue regeneration. In accordance with the findings, the Gel/Ch/PCL-Que/Cur NFP-matrix could represent an effective wound-healing dressing for BWs. © 2024 Elsevier B.V.
Retraction notice to “In vitro and in vivo assessment of curcumin-quercetin loaded multi-layered 3D-nanofibroporous matrix prepared by solution blow-spinning for full-thickness burn wound healing” [Int. J. Biol. Macromol. 270P1 (2024) 132269] (International Journal of Biological Macromolecules (2024) 270(P1), (S0141813024030745), (10.1016/j.ijbiomac.2024.132269))
(Elsevier B.V., 2025) Soumya Katiyar; Divakar Singh; Abhay Dev Tripathi; Avinash Kumar Chaurasia; Ritika Kumari Singh; Pradeep Kumar Srivastava; Abha Mishra
This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editors-in-Chief. Concerns were raised about several instances of image duplications in Figs. 2, 7 and 9(a), where images seem to depict the same samples, but are labeled as different samples, with changes in focus and contrast. The corresponding author responded to these concerns but was unable to provide a satisfactory explanation and consequently the Editors-in-Chief decided to retract the article. © 2024 Elsevier B.V.
Ursolic acid attenuates oxidative stress in nigrostriatal tissue and improves neurobehavioral activity in MPTP-induced Parkinsonian mouse model
(Elsevier, 2016) Sachchida Nand Rai; Satyndra Kumar Yadav; Divakar Singh; Surya Pratap Singh
Parkinson's disease (PD) is characterized by a slow and progressive degeneration of dopaminergic neurons in substantia nigra pars compacta (SNpc) region of brain. Oxidative stress and inflammation plays important role in the neurodegeneration and development of PD. Ursolic Acid (UA: 3β-hydroxy-urs-12-en-28-oic acid) is a natural pentacyclic triterpenoid found in various medicinal plants. Its anti-inflammatory and antioxidant activity is a well-established fact. In this paper, the neuroprotective efficiency of UA in MPTP induced PD mouse model has been explored. For this purpose, we divided 30 mice into 5 different groups; first was control, second was MPTP-treated, third, fourth and fifth were different doses of UA viz., 5 mg/kg, 25 mg/kg, and 50 mg/kg body weight (wt) respectively, along with MPTP. After 21 days of treatment, different behavioral parameters and biochemical assays were conducted. Tyrosine hydroxylase (TH) immunostaining of SN dopaminergic neurons as well as HPLC quantification of dopamine and its metabolites 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanilic acid (HVA) were also performed. Our results proved that, UA improves behavioral deficits, restored altered dopamine level and protect dopaminergic neurons in the MPTP intoxicated mouse. Among three different doses, 25. mg/kg body wt was the most effective dose for the PD. This work reveals the potential of UA as a promising drug candidate for PD treatment. © 2015 Elsevier B.V.