Papia Haque

Preparation and Characterization of Jute Cellulose Crystals-Reinforced Poly(L-lactic acid) Biocomposite for Biomedical Applications

Crystalline cellulose was extracted from jute by hydrolysis with 40% H2SO4 to get mixture of micro/nanocrystals. Scanning electron microscope (SEM) showed the microcrystalline structure of cellulose and XRD indicated the Iβ polymorph of cellulose. Biodegradable composites were prepared using crystalline cellulose (CC) of jute as the reinforcement (3–15%) and poly(lactic acid) (PLA) as a matrix by extrusion and hot press method. CC was cellulose derived from mercerized and bleached jute fiber by acid hydrolysis to remove the amorphous regions. FT-IR studies showed hydrogen bonding between the CC and the PLA matrix. The X-ray diffraction (XRD) and differential scanning calorimetry (DSC) studies showed that the percentage crystallinity of PLA in composites was found to be higher than that of neat PLA as a result of the nucleating ability of the crystalline cellulose. Furthermore, Vicker hardness and yield strength were found to increase with increasing cellulose content in the composite. The SEM images of the fracture surfaces of the composites were indicative of poor adhesion between the CC and the PLA matrix. The composite with 15% CC showed antibacterial effect though pure films but had no antimicrobial effect; on the other hand its cytotoxicity in biological medium was found to be medium which might be suitable for its potential biomedical applications.

Preparation and characterization of poly (ethylene glycol) grafted Ca-alginate fibers by γ-irradiation for biomedical applications

Radiation processing, being a physical process, is an environmentally friendly alternative to chemical modifications. It is economically viable, safe, and possesses several advantages over other conventional methods employed for modification and grafting. To improve the physico-mechanical properties of Ca-alginate fiber (CaAF), poly (ethylene glycol) (PEG) was grafted by applying γ-radiation of different intensities. The effect of γ-irradiation on the physico-mechanical, thermal, morphological, thermal and water aging, water, and simulated body fluid (SBF) uptake were evaluated. FT-IR results confirmed that PEG was successfully grafted onto Ca-alginate fibers by γ-irradiation. From the detailed experimental results, irradiation doses and PEG concentration were optimized for grafting processes. The results showed that 50% PEG and 2.5 kGy irradiation dose yielded the highest tensile strength. Differential scanning calorimetric (DSC) analysis showed that with increasing γ-intensity a decrease of dehydration temperature of the fibers had occurred. On the other hand, the glass transition temperature (T g) increased with increasing irradiation dose. The tensile cracked surfaces of the grafted alginate fibers were analyzed by scanning electron microscope (SEM) in order to monitor their surface morphologies. The SEM images of the cracked surfaces demonstrated that spherical shape rods were present for irradiated fiber sample while no such rods were observed for non-irradiated fibers. The characteristic data obtained from SBF and water uptake, and water and thermal aging experiments indicated that CaAF grafted with 50% PEG by applying 2.5 kGy γ-irradiation can be potentially employed for biomedical purposes, such as surgical suture.

Potato starch-reinforced poly(vinyl alcohol) and poly(lactic acid) composites for biomedical applications:

Starch platelets of micro particle size in the range of 10–100 µm were extracted from potato by acid hydrolysis. Two types of starch-reinforced composites, one with poly(vinyl alcohol) (PVA) and the other with poly(lactic acid) (PLA), were prepared by solvent casting and hot press molding methods, respectively. Mechanical properties of the starch/PVA and the starch/PLA composites were determined, and the maximum tensile and yield strength obtained were around 19.7 MPa for 6% starch/PVA composite and around 7.2 MPa for 6% starch/PLA composite, correspondingly. The structure of both the composites were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis (differential thermal analysis/differential thermogravimetric analysis), thermomechanical analysis, and scanning electron microscopy. Finally, antimicrobial test was conducted to assess the potentiality of both the composites to be used for biomedical applications and only starch/PVA composite was observed to inhibit microbial growth against both a gram-positive (Bacillus subtillis) and a gram-negative (Escherichia coli) bacteria.

Recent Updates on Immobilization of Microbial Cellulase

Several new types of carriers and techniques have been implemented in recent years to improve the traditional cellulase immobilization process, which aims to enhance its loading, activity, and stability with reduced cost for various industrial applications. This chapter summarizes the recent advancements in all aspects of microbial cellulase enzyme like the types of cellulases, their microbial sources, structure, and properties, immobilization factors, and industrial applications. Common cellulase inducers and existing immobilization matrices are highlighted along with insights into the recent developments for each of them. Different immobilization techniques, the types of reactors used so far, and their effect on the immobilized cellulase are thoroughly discussed. More importantly, this review focuses on the future immobilization processes of cellulase and their potential for the most modern industrial applications.

Cellulase in Waste Management Applications

Our society produces a lot of voluminous waste of biomass every day, which are mainly lignocellulose in origin. It is the most abundant plant cell wall component of the biosphere and the most plentiful biological compound on terrestrial earth. The successful conversion of cellulosic waste from domestic, industrial, and municipal sources through economically feasible processes to valuable by-products has long been admitted as a desirable endeavor. The degradation of cellulosic materials has gained increasing attention due to its worldwide availability and enormous potential for transforming them into sugars, fuels, and chemical feedstocks. Enzymatic hydrolysis of cellulosic biomass holds tremendous promise due to the high specificity and production of high yields of glucose without generation of degradation products, unlike acid/alkali hydrolysis. It has lower utility cost and hydrolysis occurs under mild reaction conditions. Microorganisms that degrade cellulose are abundant and universal in nature. The enzymatic hydrolysis of cellulose requires the use of cellulase enzyme. Fungi and bacteria are the main cellulase-producing microorganisms. A “twofold” benefit could be achieved through a sustainable bioconversion of biomass by cellulase enzyme. First, it would reduce the amount of cellulosic waste and diminish its effects on our environment; and second, the bioconversion of waste would be an alternative source of fuel energy to shrink our growing dependence on fossil fuels.

Benefits of Renewable Hydrogels over Acrylate- and Acrylamide-Based Hydrogels

In recent years, renewable/biodegradable polymer-based hydrogels have attracted great interest in the field of hydrogel research and development. The reasons of this interest are their applications in versatile fields including personal care products; drug delivery systems; wound healing; tissue engineering; industrial, pharmaceutical, and biomedical, agricultures; water treatments; food packaging; etc. Other important reasons are the problems caused by synthetic sources to the environment. Therefore, it is our demand to develop natural materials that can be biocompatible and biodegradable with the environment, and important efforts are focused on finding alternatives to replace the synthetic one. Furthermore, A. K. Mallik (*) · M. Shahruzzaman · M. N. Sakib · A. Zaman · M. S. Rahman · M. M. Islam · M. S. Islam · P. Haque · M. M. Rahman Department of Applied Chemistry and Chemical Engineering, Faculty of Engineering and Technology, University of Dhaka, Dhaka, Bangladesh e-mail: abulkmallik@du.ac.bd; shahruzzaman@du.ac.bd; nsakib@du.ac.bd; asad.acce@du.ac.bd; shiraj@du.ac.bd; minhajul.acce@du.ac.bd; sazid@du.ac.bd; papiahq@yahoo.com; mizanur. rahman@du.ac.bd # Springer International Publishing AG, part of Springer Nature 2018 Md. I. H. Mondal (ed.), Cellulose-Based Superabsorbent Hydrogels, Polymers and Polymeric Composites: A Reference Series, https://doi.org/10.1007/978-3-319-76573-0_10-1 1 renewable hydrogels display unique properties such as biodegradability, biocompatibility, stimuli-responsive characteristics and biological functions. Natural hydrogels are often based on polysaccharide or protein chains. Due to the hydrophilic structure of polysaccharides, they have a good property to form hydrogel. There are various polysaccharides like starch, cellulose, sodium alginate, chitosan, guar gum, carrageenan, etc. that have been focused and used for the preparation of environmental friendly hydrogels. Among them, cellulose and its derivatives revealed distinctive benefits because they are the most abundant natural polysaccharide having low cost and better biodegradability and biocompatibility. Protein chains, which form natural hydrogels, are collagen, silk, keratin, elastin, resilin, and gelatin. On the other hand, many synthetic polymers/ copolymers also form hydrogel like poly(vinyl alcohol), polyacrylamide, poly (ethylene oxide), poly(ethylene glycol), etc. Synthetic polymer-based hydrogels have one benefit of chemical strength than natural counterpart due to the slower degradation rate of the hydrolyzable moieties. However, biorenewable polymers usually present higher biocompatibility compared to synthetic polymers, as they undergo enzyme-controlled biodegradation by human enzymes (e.g., lysozyme) and produce biocompatible by-products. This chapter focused on the advantages of biorenewable hydrogels over synthetic (acrylateand acrylamide-based) hydrogels.

Gelatin-Based Hydrogels

Hydrogels are crosslinked polymers that are able to absorb large amount of water, permit solutes within their swollen matrices, and provide sustained delivery of absorbed solutes. The use of various types of functional biopolymers as scaffold materials in hydrogels has become of great interest not only as an underutilized resource but also as a new functional material of high potential in various fields. T. U. Rashid (*) · S. Sharmeen · S. Biswas · T. Ahmed · A. K. Mallik · M. Shahruzzaman · M. Nurus Sakib · P. Haque · M. M. Rahman Department of Applied Chemistry and Chemical Engineering, Faculty of Engineering and Technology, University of Dhaka, Dhaka, Bangladesh e-mail: taslim@du.ac.bd # Springer International Publishing AG, part of Springer Nature 2018 Md. I. H. Mondal (ed.), Cellulose-Based Superabsorbent Hydrogels, Polymers and Polymeric Composites: A Reference Series, https://doi.org/10.1007/978-3-319-76573-0_53-1 1 Among them, gelatin has been considered as highly potential candidate to be utilized as hydrogel component because of its hydration properties such as swelling and solubility; gelling behavior such as gel formation, texturizing, thickening, and water-binding capacity; and surface behavior like emulsion and foam formation, stabilization, adhesion and cohesion, protective colloid function, and film-forming capacity. In addition, its properties of biocompatibility, low toxicity, antimicrobial activity, and biodegradability make it suitable for diversified biomedical applications. Many works have been reported in various scientifically reputable journals and publications worldwide that seem to have potential or satisfactory contribution of gelatin-based hydrogels. Numerous fields of application of gelatin hydrogels include, not limited to, usage as safer release system in agrochemicals, nutrient carriers for plants, drug and cell carrying devices, bioadhesives, wound healing, tissue engineering, etc. The purpose of this chapter is to compile the recent information on developments in gelatin-based hydrogel preparation, as well as new processing conditions and potential novel or improved applications.

Preparation and properties of biodegradable polymer/nano-hydroxyapatite bioceramic scaffold for spongy bone regeneration

Abstract Biodegradable polymer/bioceramic composite scaffolds can overcome the limitations of conventional ceramic bone substitutes, such as brittleness and difficulty in shaping. To better mimic the mineral components and microstructure of natural bone, a novel nano-hydroxyapatite (nHAp)–chitosan composite scaffold including gelatin and polymer (poly(lactic acid)) with high porosity was developed using a sol-gel method and subsequently lyophilized for efficient bone tissue engineering. The nanocrystalline structure of hydroxyapatite was observed using X-ray diffraction analysis and the composite showed crystallinity due to the presence of nHAp. The pore diameter of the composite containing 5% nHAp was found to be 125 μm, while the composites with 10%, 15%, and 20% nHAp revealed a smaller pore size in the range of 15–28 μm. The highest compressive strength of 5.5 MPa was observed for the 10% nHAp-containing scaffold, whereas thermogravimetric analysis showed 90%–94% degradation at a temperature of 600°C, which demonstrated its excellent thermal stability. Antibacterial and cytotoxicity test results revealed that the composite is resistant toward microbial attack and has low sensitivity in cytotoxicity. The compressive strength data suggests that the composite does not have enough strength as that of human compact bone; however, the highly porous structure as observed in scanning electron microscopy makes it possible for use as an excellent substrate in the spongy bone of humans.

Scope of Sustainable Pretreatment of Cotton Knit Fabric Avoiding Major Chemicals

ABSTRACT The present effort attempted to avoid basic chemicals, namely NaOH and H2O2 in scouring and bleaching of cotton knit fabric in order to reduce the chemical load and processing cycles without compromise of dyeing performance. Single jersey single lacoste cotton knit fabrics treated with detergent and wetting agent at 120°C temperature for 20 minutes revealed 5.8% weight loss. FTIR graphical data validated the weakening and moving out of characteristic bands of wax and pectin-based cotton impurities in the region of 1740–1200 cm−1. The color differences of 1.5% and 1% dyed samples confirmed pass value (CMC ΔE ≤ 1) when treated at 105°C temperature for 20 minutes. The grading for color fastness to wash, perspiration, rubbing and light was 4–5 to 5. No deterioration in strength and morphological changes were experienced for the treated samples.

Analytical Method Validation of Testosterone Undecanoate Soft Gelatin Capsule by RP-HPLC Method

A rapid, sensitive, selective reversed phase HPLC method has been validated for the quantification of testosterone undecanoate from Andriol® soft gelatin capsule. During validation active pharmaceutical ingredient (API) has been separated by C18 (4.6 mm × 250 mm, 5 μm) column, 100% methanol as mobile phase, flow rate of 0.8 ml/min and detection wavelength at 240 nm. The method was validated according to USP and ICH guideline requirements which includes specificity, accuracy, precision, linearity and range and robustness. Linearity of standard spiked sample was observed for each working day and coefficient of determination (r2) has been found >0.99 each day in concentration ranging from 20-60 ppm. Recovery was found from 98.87-100.02% for 20, 40 and 60 ppm of testosterone undecanoate spiked sample. Precision and intermediate precision showed that % RSD of test sample solution were 0.26 and 0.19 respectively and absolute difference between them was 0.52, all of the values were within acceptable limit. The method was also found robust in changing column oven temperature (± 5°C) and flow rate change (± 0.1).