Shakeel Ahmad Khan

Bio: Shakeel Ahmad Khan is an academic researcher from City University of Hong Kong. The author has contributed to research in topics: Formazan & DPPH. The author has an hindex of 15, co-authored 37 publications receiving 840 citations. Previous affiliations of Shakeel Ahmad Khan include University of Management and Technology, Lahore & Government College University, Faisalabad.

Green synthesis of copper oxide nanoparticles using Abutilon indicum leaf extract: Antimicrobial, antioxidant and photocatalytic dye degradation activitie

Abstract: Purpose: To synthesize copper oxide (CuO) nanoparticles using a ecofriendly technique and evaluate their antimicrobial, antioxidant and photo-catalytic dye degradation potentials. Methods: A superficial method (solution combustion method) was employed for the synthesis of copper oxide nanoparticles from an aqueous extract of Abutilon indicum . The CuO nanoparticles were characterized using x-ray diffraction (XRD), energy-dispersive x-ray spectroscopy (EDX), scanning electron microscope (SEM) and ultraviolet-visible (UV-Vis) spectroscopic techniques. The antimicrobial activity of the CuO nanoparticles was determined by agar well diffusion method, while their antioxidant properties were assessed by DPPH radical scavenging, ferric reducing antioxidant power (FRAP), total antioxidant, ferric thiocyanate (FTC) and total phenolic content (TPC) assays. The photo-catalytic degradation activity of synthesized CuO nanoparticles was assessed by the degradation of Acid Black 210 (AB) dye under sunlight irradiation. Results: XRD, EDX and SEM results confirmed successful synthesis of CuO nanoparticles, with hexagonal, wurtzite and sponge crystal structure. Photo-catalytic data revealed that the nanoparticles are a good catalyst for effective degradation of Acid Black 210. The nanoparticles also exhibited remarkable antioxidant activity, with IC 50 and FRAP values ranging from 40 ± 0.23 to 84 ± 0.32 μg/ml, and 0.65 ± 0.01 to 9.10 ± 0.21 Trolox equivalent/mL, respectively. Significant bactericidal activity was manifested by the CuO nanoparticles against Klebsiella and Bacillus subtilis with zone of inhibition of 14 ± 0.05 and 15 ± 0.11 mm, respectively. Conclusion: The synthesized CuO nanoparticles exhibit antibacterial and antioxidant potential, indicating that they are good candidates for future therapeutic applications. Keywords: CuO nanoparticles, Green synthesis, Photo-catalytic degradation, Antioxidant, Antimicrobial

Synthesis of TiO2/Graphene oxide nanocomposites for their enhanced photocatalytic activity against methylene blue dye and ciprofloxacin

Abstract: We report the synthesis of TiO2/Graphene oxide nanocomposites (2%, 4%, 6% and 8%) by liquid phase deposition of titania on graphene oxide (GO) nanosheets. This chemical method of synthesis was used due to hydrophobic/hydrophilic incompatibility of GO with metal oxides. The fabricated TiO2/GO nanocomposites were successfully characterized using various diffraction, electron microscopy and spectroscopic techniques i.e. X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), Energy-Dispersive X-Ray (EDX), Ultra-Violet Visible, Diffuse Reflectance Spectroscopy (DRS) and Fourier Transform Infra Red (FTIR). Photocatalytic activity against methylene blue dye and ciprofloxacin was carried out by the synthesized nanocomposites under sun light spectrum. Results were revealed that average crystallite size (12.42 nm, and 12.50 nm) was observed for the synthesized pure TiO2 and TiO2/GO (8%) nanocomposites respectively with crystalline nature and spherical morphology. Moreover, synthesized TiO2/GO (8%) nanocomposites were found to have larger surface area (91.25 m2g-1) and narrow energy band-gap values (2.47 eV) than that of pure TiO2 (55.93 m2g-1 and 3.06 eV) respectively. Furthermore, the TiO2/GO (8%) nanocomposites exhibited fastest and highest rate of photocatalytic degradation of methylene blue among all composites (2%, 4%, and 6%) and pure TiO2 in much reduced period. Their excellent photocatalytic activity against synthetic dye and ciprofloxacin under the spectrum of visible region was attributed to thin two dimensional sheet support, larger surface area, narrow band gap, higher adsorption capacity and good electron acceptability of GO. Hence, the fabricated nanocomponents could be proved valuable photocatalytic system to safe our environs from the intimidations of toxic waste products produced by different industries.

Green Synthesis of Gold and Silver Nanoparticles Using Leaf Extract of Clerodendrum inerme; Characterization, Antimicrobial, and Antioxidant Activities

Abstract: Due to their versatile applications, gold (Au) and silver (Ag) nanoparticles (NPs) have been synthesized by many approaches, including green processes using plant extracts for reducing metal ions. In this work, we propose to use plant extract with active biomedical components for NPs synthesis, aiming to obtain NPs inheriting the biomedical functions of the plants. By using leaves extract of Clerodendrum inerme (C. inerme) as both a reducing agent and a capping agent, we have synthesized gold (CI-Au) and silver (CI-Ag) NPs covered with biomedically active functional groups from C. inerme. The synthesized NPs were evaluated for different biological activities such as antibacterial and antimycotic against different pathogenic microbes (B. subtilis, S. aureus, Klebsiella, and E. coli) and (A. niger, T. harzianum, and A. flavus), respectively, using agar well diffusion assays. The antimicrobial propensity of NPs further assessed by reactive oxygen species (ROS) glutathione (GSH) and FTIR analysis. Biofilm inhibition activity was also carried out using colorimetric assays. The antioxidant and cytotoxic potential of CI-Au and CI-Ag NPs was determined using DPPH free radical scavenging and MTT assay, respectively. The CI-Au and CI-Ag NPs were demonstrated to have much better antioxidant in terms of %DPPH scavenging (75.85% ± 0.67% and 78.87% ± 0.19%), respectively. They exhibited excellent antibacterial, antimycotic, biofilm inhibition and cytotoxic performance against pathogenic microbes and MCF-7 cells compared to commercial Au and Ag NPs functionalized with dodecanethiol and PVP, respectively. The biocompatibility test further corroborated that CI-Ag and CI-Au NPs are more biocompatible at the concentration level of 1–50 µM. Hence, this work opens a new environmentally-friendly path for synthesizing nanomaterials inherited with enhanced and/or additional biomedical functionalities inherited from their herbal sources.

Antimicrobial Peptides: Classification, Design, Application and Research Progress in Multiple Fields

Abstract: Antimicrobial peptides (AMPs) are a class of small peptides that widely exist in nature and they are an important part of the innate immune system of different organisms. AMPs have a wide range of inhibitory effects against bacteria, fungi, parasites and viruses. The emergence of antibiotic-resistant microorganisms and the increasing of concerns about the use of antibiotics resulted in the development of AMPs, which have a good application prospect in medicine, food, animal husbandry, agriculture and aquaculture. This review introduces the progress of research on AMPs comprehensively and systematically, including their classification, mechanism of action, design methods, environmental factors affecting their activity, application status, prospects in various fields and problems to be solved. The research progress on antivirus peptides, especially anti-coronavirus (COVID-19) peptides, has been introduced given the COVID-19 pandemic worldwide in 2020.

Green synthesis of copper oxide nanoparticles using Abutilon indicum leaf extract: Antimicrobial, antioxidant and photocatalytic dye degradation activitie

Abstract: Purpose: To synthesize copper oxide (CuO) nanoparticles using a ecofriendly technique and evaluate their antimicrobial, antioxidant and photo-catalytic dye degradation potentials. Methods: A superficial method (solution combustion method) was employed for the synthesis of copper oxide nanoparticles from an aqueous extract of Abutilon indicum . The CuO nanoparticles were characterized using x-ray diffraction (XRD), energy-dispersive x-ray spectroscopy (EDX), scanning electron microscope (SEM) and ultraviolet-visible (UV-Vis) spectroscopic techniques. The antimicrobial activity of the CuO nanoparticles was determined by agar well diffusion method, while their antioxidant properties were assessed by DPPH radical scavenging, ferric reducing antioxidant power (FRAP), total antioxidant, ferric thiocyanate (FTC) and total phenolic content (TPC) assays. The photo-catalytic degradation activity of synthesized CuO nanoparticles was assessed by the degradation of Acid Black 210 (AB) dye under sunlight irradiation. Results: XRD, EDX and SEM results confirmed successful synthesis of CuO nanoparticles, with hexagonal, wurtzite and sponge crystal structure. Photo-catalytic data revealed that the nanoparticles are a good catalyst for effective degradation of Acid Black 210. The nanoparticles also exhibited remarkable antioxidant activity, with IC 50 and FRAP values ranging from 40 ± 0.23 to 84 ± 0.32 μg/ml, and 0.65 ± 0.01 to 9.10 ± 0.21 Trolox equivalent/mL, respectively. Significant bactericidal activity was manifested by the CuO nanoparticles against Klebsiella and Bacillus subtilis with zone of inhibition of 14 ± 0.05 and 15 ± 0.11 mm, respectively. Conclusion: The synthesized CuO nanoparticles exhibit antibacterial and antioxidant potential, indicating that they are good candidates for future therapeutic applications. Keywords: CuO nanoparticles, Green synthesis, Photo-catalytic degradation, Antioxidant, Antimicrobial