Vol.:(0123456789) 1 3 Applied Nanoscience https://doi.org/10.1007/s13204-019-01103-4 ORIGINAL ARTICLE Silver nano‑particles: synthesis and characterization by using glucans extracted from Pleurotus ostreatus Asma Irshad 1  · Nadeem Sarwar 2  · Haleema Sadia 3  · Muhammad Riaz 4  · Sumaira Sharif 5  · Muhammad Shahid 6  · Junaid Ali Khan 7 Received: 14 March 2019 / Accepted: 29 June 2019 © King Abdulaziz City for Science and Technology 2019 Abstract The extensive use of antibiotics has led to drug-resistant bacteria, which is a major public health issue worldwide. Silver nano-particles have been recognized as efcient broad-spectrum antimicrobial agent. It uses mushroom glucans as reducing and capping agent to reduce its toxicity. In the present work, we performed the characterization of glucans and glucan– AgNPs. The crude glucans were extracted by hot water then fractionated and purifed by anion exchange chromatography (DEAE-cellulose 52); the elution of glucans was monitored by phenol sulfuric acid assay. The major fractions were further purifed with gel fltration chromatography (Sephadex-G200) then lyophilized. Green synthesis of silver nano-particles was performed by glucans from selected Pleurotus spps. Extracted glucans and synthesized glucan–AgNPs were confrmed by UV–Vis spectra at 190–250 nm and 380–420 nm, respectively. Size of glucan–AgNPs (100.1 nm) was determined by dynamic light scattering. The glucans were characterized by FT-IR, SEM and XRD while glucan–AgNPs were character- ized by FT-IR, SEM–EDS, TEM and XRD. Based on FT-IR spectra, the functional groups associated with the glucans and glucan–AgNPs were determined. SEM analysis revealed that the structure of glucan was spongy with asymmetrical particle size while SEM–EDS/TEM analysis revealed the glucan–AgNPs were spherical with size range of 15–45 nm for Pleurotus ostreatus. XRD spectra of glucan showed difraction peaks at 2θ = 5.9°, 10.1° and 19.6°. By SEM–EDS/TEM analysis, the silver nano-particles against Braggs refection planes of (111), (200), (220) and (311) in X-ray difraction, showed difraction at 2θ = 38.2°, 44.5°, 64.7° and 77.5° in pattern. Keywords Pleurotus ostreatus · Glucans · Green synthesis · Characterization · Glucan–AgNPs Introduction Among the medicinal mushrooms β-glucans are the most extensively explored group of bioactive substance. The struc- ture of β-glucans consists of β-(1–3) backbone branched with short β-(1–6) linked side chains (Grundemann et al. 2015; Su et al. 2016). Glycosidic bond connects repeating units of either mono-or disaccharides to form polysaccharides, named as glucans. They are heterogenic in nature and represent non- allergic, water insoluble cell wall constituents. In some plants, fungi and bacteria are diferent in bonding pattern (either in alpha (α) or beta (β)) and in repeating units with branching positions of (1–2, 1–3, 1–4 and 1–6) (Ruthes et al. 2015). The AgNPs are synthesized by diferent polysaccharides like β-D-glucose, soluble starch, starch, cashew gum, hyaluronic acid and chitosan. β-Glucans can also be utilized for prepara- tion of AgNPs or other nano-sized metal structures, because they can reduce metal ions like Au, Ag, Pt and prevent the * Asma Irshad asmairshad76@yahoo.com; asma.irshad@cemb.edu.pk 1 National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore 54000, Pakistan 2 Department of Computer Science, Bahria University Lahore Campus, Lahore, Pakistan 3 Department of Biotechnology, BUITEM, Quetta, Pakistan 4 Department of Allied Health Sciences, Sargodha Medical College, University of Sargodha, Sargodha, Pakistan 5 College of Biosystem Engineering and Food Science, Zhejiang University, Hangzhou, China 6 Department of Biochemistry, University of Agriculture, Faisalabad, Pakistan 7 Institute of Pharmacy, Physiology and Pharmacology, University of Agriculture, Faisalabad, Pakistan