Showing papers by "Dinesh K. Patel published in 2019"

Functional cellulose-based hydrogels as extracellular matrices for tissue engineering

Abstract: Cellulose-based hydrogels are immensely important for tissue engineering. In this review, we attempt to document the source, nature, and application of cellulose-based hydrogels as an extracellular matrix for tissue growth and regeneration. Hydrogels can be prepared either from native cellulose, including both bacterial and plant sources or from cellulose derivatives, such as methyl cellulose, carboxymethylcellulose, and hydroxypropylmethylcellulose or even metal ions such as silver. Cellulose-polymer composite (polymers that include natural sources including chitosan, starch, alginates, collagen, hyaluronic acid, and chitin) are an attractive, inexpensive, and advantageous structural material that is easy to use. Cellulose-based scaffolding materials are widely used in the regeneration of various tissues, such as bone, cartilage, heart, blood vessel, nerve, and liver, among others. In this review, we discuss the most important applications of cellulosic hydrogels in tissue engineering based on their structural compositions.

Nanocellulose-based polymer hybrids and their emerging applications in biomedical engineering and water purification

Abstract: Nanocellulose, derived from cellulose hydrolysis, has unique optical and mechanical properties, high surface area, and good biocompatibility. It is frequently used as a reinforcing agent to improve the native properties of materials. The presence of functional groups in its surface enables the alteration of its behavior and its use under different conditions. Nanocellulose is typically used in the form of cellulose nanocrystals (CNCs), cellulose nanofibers (CNFs), or bacterial nanocellulose (BNC). CNCs and CNFs have a high aspect ratio with typical lengths of ∼100–250 nm and 0.1–2 μm, respectively; BNC is nanostructured cellulose produced by bacteria. Nanohybrid materials are a combination of organic or inorganic nanomaterials with macromolecules forming a single composite and typically exhibit superior optical, thermal, and mechanical properties to those of native polymers, owing to the greater interactions between the macromolecule matrix and the nanomaterials. Excellent biocompatibility and biodegradability make nanocellulose an ideal material for applications in biomedicine. Unlike native polymers, nanocellulose-based nanohybrids exhibit a sustained drug release ability, which can be further optimized by changing the content or chemical environment of the nanocellulose, as well as the external stimuli, such as the pH and electric fields. In this review, we describe the process of extraction of nanocellulose from different natural sources; its effects on the structural, morphological, and mechanical properties of polymers; and its various applications.

Nanohybrid Scaffold of Chitosan and Functionalized Graphene Oxide for Controlled Drug Delivery and Bone Regeneration.

Abstract: Nanohybrid scaffolds of chitosan have been designed for controlled drug delivery and bone regeneration. Sulfonated graphene oxide has been used to develop the nanohybrids. Nanohybrid scaffolds show...

In Vitro Biocompatibility of Electrospun Poly(ε-Caprolactone)/Cellulose Nanocrystals-Nanofibers for Tissue Engineering

Abstract: Cellulose nanocrystals (CNCs) have emerged as promising materials for the fabrication of micro/nanoplatforms that can replace tissues more effectively. CNCs offer interesting properties that facilitate the enhancement of polymer properties. Cytotoxicity of rice husk-derived CNCs was evaluated through WST-1 assay in the presence of human mesenchymal stem cells. Electrospinning technique was used to fabricate nanofibers of poly-e-caprolactone and its composites. Significant improvement in the mechanical property was observed in the composites relative to the pure polymer. This improvement was attributed to the better interfacial interactions between the polymer matrix and CNCs. Notably, better cell viability and differentiation were observed with the composite nanofibers than with the pure polymers. The osteogenic potential of the fabricated nanofibers was assessed by alizarin red S staining and real-time PCR. Enhanced mineralization occurred in the presence of the composite rather than pure polymer nanofibers. Furthermore, the higher levels of osteogenic markers observed with the media containing the composites clearly indicated their osteogenic potential. These results suggested that fabricated composites have the potential to be used as a biomaterial for tissue engineering applications.

Enhanced Osteogenesis of Human Mesenchymal Stem Cells in Presence of Single-Walled Carbon Nanotubes

Abstract: Human mesenchymal stem cells (hMSCs) have attracted significant attention for tissue engineering because of their ability to differentiate into bone cells, chondrocytes, adipocytes, and muscle cells. Single-walled carbon nanotubes (SWCNTs) have been considered as a potential material for tissue engineering applications due to their unique properties, such as high aspect ratio, excellent electrocatalytic activity, and biocompatibility. Here we prepared exfoliated SWCNTs layers through an ultra-sonication process in the acidic medium and evaluated their cytotoxicity using hMSCs. Improved viability and osteogenesis of hMSCs were observed in the presence of exfoliated SWCNTs. Besides, the higher expression of osteogenic differentiation-related genes in the presence of exfoliated SWCNTs further confirmed their enhanced osteogenic nature. These results indicated the potential of SWCNTs as a biomaterial for tissue engineering applications.

Biomimetic Polymer-Based Engineered Scaffolds for Improved Stem Cell Function.

Abstract: Scaffolds are considered promising materials for tissue engineering applications due to their unique physiochemical properties. The high porosity and adequate mechanical properties of the scaffolds facilitate greater cell adhesion, proliferation, and differentiation. Stem cells are frequently applied in tissue engineering applications due to their excellent potential. It has been noted that cell functions are profoundly affected by the nature of the extracellular matrix (ECM). Naturally derived ECM contains the bioactive motif that also influences the immune response of the organism. The properties of polymer scaffolds mean they can resemble the native ECM and can regulate cellular responses. Various techniques such as electrospinning and 3D printing, among others, are frequently used to fabricate polymer scaffolds, and their cellular responses are different with each technique. Furthermore, enhanced cell viability, as well as the differentiation ability of stem cells on the surface of scaffolds, opens a fascinating approach to the formation of ECM-like environments for tissue engineering applications.

Enhanced osteogenesis of mesenchymal stem cells on electrospun cellulose nanocrystals/poly(ε-caprolactone) nanofibers on graphene oxide substrates

Abstract: Cellulose nanocrystals (CNCs) have received a great amount of attention to the production of micro/nano-platforms for tissue engineering applications. CNCs were extracted from rice husk biomass and characterized by different spectroscopic techniques. The biocompatibility of the extracted CNCs was revealed by the WST-1 assay technique in the presence of human mesenchymal stem cells (hMSCs) after different time intervals. An improvement in the mechanical properties was observed in the fabricated scaffolds (PCL/CNC) compared to PCL scaffolds. Graphene oxide (GO)-coated (PCL/CNC) electrospun scaffolds (GPC) were prepared by the deposition of PCL/CNC composite nanofibers on the surface of GO for tissue engineering. Notably, better cell proliferation and differentiation were observed in the presence of the fabricated scaffolds. This enhancement of the properties of the fabricated scaffolds was due to the presence of conductive GO moieties which facilitated the cellular response. Therefore, the fabricated materials have the potential to be used as a biomaterial for enhanced cell proliferation and osteogenic differentiation.

Structural Elucidation and Immune-Enhancing Effects of Novel Polysaccharide from Grifola frondosa

Abstract: Beta-glucan (β-glucan) is a macromolecule structure where glucose unit has bonded through β-glycosidic bond at 1 and 3 positions. It is well known as a natural immunomodulator without exhibiting any side effects via enhancing immunity. Mushroom contains a large amount of β-glucan and it has anticancerous and antioxidant efficacy. Structure and physical properties of β-glucan are highly influenced by the types of mushroom. In particular, Grifola frondosa has β-1, 3 and β-1, 6 bonds in their structure. It has been noted that β-glucan content also depends upon the size of mushroom particles. The exact content of β-glucan and their immunological activity by a particle size of G. frondosa have yet to be fully elucidated. Herein, β-glucan contents were analyzed according to the particle size of leaf mushroom followed by cell activation and immunoactivity analysis. The highest β-glucan content was observed at a particle size of 20-30 μm (27.65 ± 0.30 w/w). All samples showed ~ 103% cell activation compared to the control and greater cell activity was observed at higher concentration. The significant increase in cytokines secretion was observed in the presence of 20-30 μm particle size of G. frondosa compared to the control. This study suggested that 20-30 μm size is the suitable size of G. frondosa that can be used as a health supplement and food additive to act as an immune booster, hypotensive agent, and hypoglycemic agent.

Synthesis and Characterization of Eggshell-Derived Hydroxyapatite Bioceramics

Abstract: Several methods are frequently used to make high-value-added biomaterials from waste biomass for various biomedical applications. Hydroxyapatite (HA), a type of bio-ceramic material, has received considerable attention for use in bone tissue and implanted medical devices owing to its physiochemical properties and excellent biocompatibility. It can be synthesized from calcium- and phosphorous-containing precursor moieties such as calcium oxide and tricalcium phosphate (TCP). In this study, we synthesized an HA bio-ceramic from bio-waste eggshells via a reaction between calcium oxide and TCP, followed by heat treatment. The synthesized HA was characterized through scanning electron microscopy, X-ray diffraction, and energy-dispersive X-ray spectroscopy. The material exhibited no significant cytotoxicity even at a higher concentration, indicating high biocompatibility. Our study provides an effective way of converting low-cost bio-waste eggshells into a value-added biomaterial for tissue-engineering applications.

Fluorescent‐functionalized graphene oxide for selective labeling of tumor cells

Abstract: Fluorescence probe has attracted significant attention for biomedical imaging in recent years due to their high resolution at the cellular level. Organic-based fluorescent probes with high quantum yield are widely applied in bioimaging, but most of them suffer from a serious obstacle called aggregation-caused quenching in cellular systems. New fluorophore has been designed through functionalization of graphene oxide which emphatically exhibits aggregation-induced emission along with pH-responsive nanoprobe. Significantly higher emission of this material in slightly acidic media helps to detect tumor cell by creating a sharp contrast with the image of normal cells. The reason for pH-induced enhanced emission phenomenon is revealed through aggregation of sulfonated species in acidic media. Furthermore, the biocompatible nature of the newly developed material is found to be suitable for its application in biomedical imaging for cancer detection with better accuracy at lower cost. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 1917-1924, 2019.

3D-Printed Scaffolds with Reinforced Poly (Lactic Acid)/Carbon Nanotube Filaments Based on Melt Extrusion

Abstract: Personalized medicine suitable for individual patients in tissue engineering is a significant challenge. Owing to the recent growth of 3D printing, various methods of building objects have been proposed. However, there is very little information about the mechanical properties of the pieces obtained by controlling the process variables using composite filaments. Fused deposition modeling (FDM) technology was used to fabricate new scaffolds with infill patterns, interconnected channel networks, controllable porosity, and size. Polylactic acid (PLA)/carbon nanotube (CNT) filaments were synthesized using the melt extrusion technique. An improvement in the mechanical properties was observed in composites compared with the pure polymer. Moreover, no toxicity was expressed by stem cells after 24 h of incubation in the presence of composite filaments for a high CNT concentration. Our results will aid in the scaffold design of composite filaments through the modeling of process parameters and mechanical properties.

Stimuli-Responsive Graphene Nanohybrids for Biomedical Applications.

Abstract: Stimuli-responsive materials, also known as smart materials, can change their structure and, consequently, original behavior in response to external or internal stimuli. This is due to the change in the interactions between the various functional groups. Graphene, which is a single layer of carbon atoms with a hexagonal morphology and has excellent physiochemical properties with a high surface area, is frequently used in materials science for various applications. Numerous surface functionalizations are possible for the graphene structure with different functional groups, which can be used to alter the properties of native materials. Graphene-based hybrids exhibit significant improvements in their native properties. Since functionalized graphene contains several reactive groups, the behavior of such hybrid materials can be easily tuned by changing the external conditions, which is very useful in biomedical applications. Enhanced cell proliferation and differentiation of stem cells was reported on the surfaces of graphene-based hybrids with negligible cytotoxicity. In addition, pH or light-induced drug delivery with a controlled release rate was observed for such nanohybrids. Besides, notable improvements in antimicrobial activity were observed for nanohybrids, which demonstrated their potential for biomedical applications. This review describes the physiochemical properties of graphene and graphene-based hybrid materials for stimuli-responsive drug delivery, tissue engineering, and antimicrobial applications.

Evaluation of Bone Regeneration Potential of Long-Term Soaked Natural Hydroxyapatite

Abstract: Natural hydroxyapatite (HA) was derived from pig bones (PBs) for tissue engineering applications through heat treatment. Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), X-r...