Browsing by Author "Paul, W"

Now showing 1 - 20 of 31
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    Acetylsalicylic acid loaded poly(vinyl alcohol) hemodialysis membranes: Effect of drug release on blood compatibility and permeability
    (JOURNAL OF BIOMATERIALS SCIENCE-POLYMER EDITION, 1997)
    Membranes developed from poly(vinyl alcohol) (PVA) have superior permeability because of the highly hydrophilic character of PVA. However, its blood compatibility needs to be further improved. For this we have developed acetylsalicylic acid (ASA, aspirin) loaded PVA membranes. It seems that the slow release of aspirin from the membrane provides a surface concentration of aspirin sufficient for partially inhibiting platelet adhesion. PVA membrane with 531 mu g cm(-2) of ASA loaded, may be selected for hemodialysis applications. This may help to reduce the amount of heparin infused during hemodialysis, thereby reducing the side-effects associated with the systemic administration of heparin.
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    Adsorption of human IgG on Cu2+-immobilized cellulose affinity membrane: Preliminary study
    (JOURNAL OF BIOMEDICAL MATERIALS RESEARCH, 2000)
    Immobilized metal ion affinity chromatography (IMAC) is widely used. Transition metal ions have a high affinity to some peptide sequences. We have studied the selective adsorption of human IgG from a mixture of albumin, gamma-globulin, fibrinogen, and IgG onto Cu2+ ion-immobilized cellulose membrane. Although Cu2+ ligand is selective to IgG, in general gamma-globulins also are adsorbed. The simplicity and lower cost of Cu2+ ion-immobilized cellulose membranes may be useful for removing IgG from blood. (C) 2000 John Wiley & Sons, Inc.
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    Aggregation induced Raman scattering of squaraine dye: Implementation in diagnosis of cervical cancer dysplasia by SERS imaging
    (BIOSENSORS & BIOELECTRONICS, 2015) Narayanan, N; Karunakaran, V; Paul, W; Venugopal, K; Sujathan, K; Maiti, KK
    The extent of squaraine dye aggregation that reflects on surface enhanced Raman signal scattering (SERS) intensity upon adsorption on nano-roughened gold surface has been investigated. Here we have synthesized a serious of six squaraine dyes consisting of two different electron donor moiety i.e. 1,1,2-trimethyl-1H-benzo[elindole and 2-methylbenzo[d]thiazole which modulates the chemisorptions and hydrophobicity being designated as SQ1, SQ2, SQ3, SQ4, SQ5 and SQ6. Interestingly, SQ2 (mono lipoic acid appended), SQ5 and SQ6 (conjugated with hexyl and dodecyl side chain) squaraine derivatives having more tendency of aggregation in DMSO-water mixed solvent showed significant increase of Raman scattering in the fingerprint region when chemisorbed on spherical gold nanoparticles. Two sets of SERS nanotags were prepared with colloidal gold nanoparticle (Au-NPs size: 40 nm) by incorporating Raman reporters SQ2 and SQ5 followed by thiolated PEG encapsulation (SH-PEG, SH-PEG-COOH) denoted as AuNPs-SQ2-PEG and AuNPs-SQ5-PEG. Further conjugation of these nanotag with monoclonal antibodies specific to over expressed receptors, EGFR and p16/Ki-67 in cervical cancer cell, HeLa showed prominent SERS mapping intensity and selectivity towards cell surface and nucleus. The fast and accurate recognition obtained by antibody triggered SERS-nanotag has been compared with conventional time consuming immunocytochemistry technique which prompted us to extend further investigation using real patient cervical smear sample for a non-invasive, ultrafast and accurate diagnosis. (C) 2015 Elsevier B.V. All rights reserved.
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    Aggregation of gold nanoparticles followed by methotrexate release enables Raman imaging of drug delivery
    (J Nanoparticle Res., 2012-10) Durgadas, CV; Sharma, CP; Paul, W; Rekha, MR; Sreenivasan, K
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    Aggregation of gold nanoparticles followed by methotrexate release enables Raman imaging of drug delivery into cancer cells
    (JOURNAL OF NANOPARTICLE RESEARCH, 2012) Durgadas, CV; Sharma, CP; Paul, W; Rekha, MR; Sreenivasan, K
    This study refers an aqueous synthesis of methotrexate (MTX)-conjugated gold nanoparticles (GNPs), their interaction with HepG2 cells, and the use of Raman imaging to observe cellular internalization and drug delivery. GNPs of average size 3.5-5 nm were stabilized using the amine terminated bifunctional biocompatible copolymer and amended by conjugating MTX, an anticancer drug. The nanoparticles were released MTX at a faster rate in acidic pH and subsequently found to form aggregates. The Raman signals of cellular components were found to be enhanced by the aggregated particles enabling the mapping to visualize site-specific drug delivery. The methodology seems to have potential in optimizing the characteristics of nanodrug carriers for emptying the cargo precisely at specified sites.
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    Alginate encapsulated bioadhesive chitosan microspheres for intestinal drug delivery
    (JOURNAL OF BIOMATERIALS APPLICATIONS, 1999) Ramdas, M; Dileep, KJ; Anitha, Y; Paul, W; Sharma, CP
    Sustained intestinal delivery of drugs such as Ei-fluorouracil (choice for colon carcinomas) and insulin (for diabetes mellitus) seems to be a feasible alternative to injection therapy. For successful therapy, the drug should be delivered at proper sites (here, the intestine) for long duration, for producing maximum pharmacological activity. We have attempted to develop a formulation that can bypass the acidity of the stomach and release the loaded drug for long periods into the intestine by using the bioadhesiveness of polyacrylic acid, alginate, and chitosan. Bromothymol blue was taken as a model drug. The formulation exhibited bioadhesive property and released the drug for an eight-day period in vitro.
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    Antibiotic loaded hydroxyapatite osteoconductive implant material - In vitro release studies
    (JOURNAL OF MATERIALS SCIENCE LETTERS, 1995) Paul, W; Sharma, CP
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    Blood protein adsorption and compatibility studies of gold nanoparticles
    (GOLD BULLETIN, 2011) Nimi, N; Paul, W; Sharma, CP
    Gold nanoparticles are considered to be real jewels. The significant growth of their application for labeling, delivery, heating, and sensing shows their significance in biology and/or life sciences. PEGylated gold nanoparticles also have significant application in drug and gene delivery. However, comprehensive information on the compatibility of these nanoparticles to blood is limited in literature. An attempt has been made to study the protein adsorption, blood cell aggregation, and C3 adsorption onto these particles to evaluate its complement activation potential and blood compatibility. It has been observed that these nanoparticles do not induce any complement activation or blood cell aggregation. Particles were non-hemolytic and the adsorptions of proteins were negligible which further validates its significance in drug delivery and gene delivery applications.
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    Ceramic drug delivery: A perspective
    (JOURNAL OF BIOMATERIALS APPLICATIONS, 2003)
    Different ceramic substances are offered in the market as bone substitute materials. These include monophasic calcium phosphate ceramics of tricalciumphosphate (TCP) or hydroxyapatite (HA), biphasic calcium phosphate ceramics and multiphasic bio-glasses synthetic calcium phosphate cements. Ceramics with appropriate three-dimensional geometry are able to bind and concentrate bone morphogenetic proteins in circulation and may become osteoinductive (capable of osteogenesis) and can be effective carriers of bioactive peptide or bone cell seeds and are therefore potentially useful in tissue engineering and drug delivery. An attempt has been made to review various drug delivery applications of ceramics.
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    Chitin and chitosan polymers: Chemistry, solubility and fiber formation
    (PROGRESS IN POLYMER SCIENCE, 2009) Pillai, CKS; Paul, W; Sharma, CP
    Chitin and chitosan (CS) are biopolymers having immense structural possibilities for chemical and mechanical modifications to generate novel properties, functions and applications especially in biomedical area. Despite its huge availability, the utilization of chitin has been restricted by its intractability and insolubility. The fact that chitin is as an effective material for sutures essentially because of its biocompatibility, biodegradability and non-toxicity together with its antimicrobial activity and low immunogenicity, points to immense potential for future development. This review discusses the various attempts reported on solving this problem from the point of view of the chemistry and the structure of these polymers highlighting the drawbacks and advantages of each method and proposes that based on considerations of structure-property relations, it is possible to obtain chitin fibers with improved strength by making use of their nanostructures and/or mesophase properties of chitin. (C) 2009 Elsevier Ltd. All rights reserved.
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    Chitosan scaffold co-cultured with keratinocyte and fibroblast heals full thickness skin wounds in rabbit
    (JOURNAL OF BIOMEDICAL MATERIALS RESEARCH PART A, 2014) Revi, D; Paul, W; Anilkumar, TV; Sharma, CP
    This study evaluated the modulatory effect of chitosan sponge co-cultured with keratinocyte and fibroblast on wound healing. Dermal fibroblasts and keratinocyte isolated from rabbit skin were co-cultured on chitosan sponge, to fabricate cell-loaded chitosan tissue engineered construct. Full thickness excision wounds created on the rabbit dorsum were treated with three types of graft materials - a noncellular chitosan graft, homologous keratinocyte fibroblast loaded chitosan, and a commercial product. Postgraft skin-wound samples were examined histomorphologically at 7th, 14th, and 28th day after staining with hematoxylin and eosin, picrosirius red and/or immunohistochemistry. Wound healing parameters considered were the extent of re-epithelialization, collagen deposition, and neoangiogenesis. The number of proliferating cells, vimentin positive cells, and alpha smooth muscle actin cells were also quantified. The histology results suggested that the grafts aided wound healing but, the cell-loaded graft induced a differential pattern of healing and had lower scarring tendency. The cell-loaded tissue construct may be useful as a therapeutic graft for treating wounds where there is a total loss of tissue and cells as in burn injury. (C) 2013 Wiley Periodicals, Inc.
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    Chitosan, a drug carrier for the 21st century: a review
    (STP PHARMA SCIENCES, 2000) Paul, W; Sharma, CP
    Chitosan, a polysaccharide with structural characteristics similar to glycosamino glycan, was studied for various biomedical applications including membranes in hemodialysis, artificial skin or bioactive wound dressings, as an excipient in drug delivery systems as a matrix in perfusion columns and as a material possessing hemostatic potential to promote nerve growth. Chitosan is, in fact, prescribed for obesity since it is an excellent fat binder. With these multiple applications, chitosan - a biodegradable and naturally available material - will emerge as a household name and as an important biomedical material of the 21(st) century. In this paper, we aim to present the various drug delivery applications of this interesting biopolymer.
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    Cucurbitural/Hydroxyapatite based nanoparticles for potential use in theranostic applications
    (CrystEngComm, 2014-05) Victor, SP; Paul, W; Jayabalan, M; Sharma, CP
    We present the engineering of cucurbituril/hydroxyapatite based theranostic nanoparticles with a high aspect ratio and a needle shaped morphology. These particles with varying sizes, surface charges and tunable degradation profiles manifested the advantages of the presence of cucurbituril with respect to drug loading, encapsulation efficacy and release kinetics. In vitro release profiles with two model drugs, Doxorubicin hydrochloride (Dox, hydrophilic) and Nile Red dye (NR, hydrophobic), were evaluated. It was ascertained that hydrophilic Dox was released at a faster rate compared to hydrophobic NR over similar time periods. The concomitant presence of samarium (Sm3+) and CB[7] confers theranostic potential to the synthesized nanoparticles. Cellular toxicity effects systematically assessed using MTT and live/dead assay protocols indicate inappreciable toxicity. The nanoparticles further reveal excellent blood compatibility and cellular internalization properties as visualized by fluorescence microscopy. Particles excited at 300 nm revealed Dox emission in the green channel (470 nm) as well as Sm3+ emission in the red channel (590 nm). These studies unravel the potential of these nanoparticles for effective theranostic applications.
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    Cucurbituril/hydroxyapatite based nanoparticles for potential use in theranostic applications
    (CRYSTENGCOMM, 2014) Victor, SP; Paul, W; Jayabalan, M; Sharma, CP
    We present the engineering of cucurbituril/hydroxyapatite based theranostic nanoparticles with a high aspect ratio and a needle shaped morphology. These particles with varying sizes, surface charges and tunable degradation profiles manifested the advantages of the presence of cucurbituril with respect to drug loading, encapsulation efficacy and release kinetics. In vitro release profiles with two model drugs, Doxorubicin hydrochloride (Dox, hydrophilic) and Nile Red dye (NR, hydrophobic), were evaluated. It was ascertained that hydrophilic Dox was released at a faster rate compared to hydrophobic NR over similar time periods. The concomitant presence of samarium (Sm3+) and CB[7] confers theranostic potential to the synthesized nanoparticles. Cellular toxicity effects systematically assessed using MTT and live/dead assay protocols indicate inappreciable toxicity. The nanoparticles further reveal excellent blood compatibility and cellular internalization properties as visualized by fluorescence microscopy. Particles excited at 300 nm revealed Dox emission in the green channel (470 nm) as well as Sm3+ emission in the red channel (590 nm). These studies unravel the potential of these nanoparticles for effective theranostic applications.
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    Delivery of insulin from hydroxyapatite ceramic microspheres: Preliminary in vivo studies
    (JOURNAL OF BIOMEDICAL MATERIALS RESEARCH, 2002)
    The major limiting factor in utilizing protein drugs for sustained delivery is the lack of suitable delivery systems. Ceramic hydroxyapatite microspheres are biocompatible and utilized for the purification of proteins. As a preliminary study, we have investigated the possibility of using hydorxyapatite ceramic microspheres loaded with insulin as an implantable delivery system in rats. With this limited test, it was shown-that the loaded insulin was active and able to suppress the blood glucose level in normal rats. (C) 2002 Wiley Periodicals, Inc.
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    Development and characterization of self-aggregated nanoparticles from anacardoylated chitosan as a carrier for insulin
    (CARBOHYDRATE POLYMERS, 2010) Shelma, R; Paul, W; Sharma, CP
    Nanoparticulate carriers made from biodegradable polymers especially from chitosan seems to be an excellent approach to increase the uptake and transport of orally administered insulin. Various approaches have been studied to develop nanoparticles from chitosan including self-aggregated nanoparticles from hydrophobically modified chitosan. Anacardic acid is a naturally occurring fatty acid having bulky aromatic group as well as long aliphatic chain and an amphiphilic monomer of great potential. An attempt has been made to develop and characterize self-aggregated nanoparticles from chitosan modified with anacardic acid. Anacardoylated chitosan spontaneously formed nanoparticles in aqueous insulin solution with a particles size of 214 nm diameter at neutral pH. The hydrophobic nature of the nanoparticles helped in the Sustained release of insulin in the intestinal environment and the released insulin was stable and retained its conformation. However, it released insulin in acidic conditions and need to be encapsulated in alginate to render pH sensitiveness. (C) 2009 Elsevier Ltd. All rights reserved.
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    Development of porous spherical hydroxyapatite granules: application towards protein delivery
    (JOURNAL OF MATERIALS SCIENCE-MATERIALS IN MEDICINE, 1999)
    A new method for the preparation of porous spherical hydroxyapatite granules is reported. It may be clinically applied towards orthopaedic or maxillofacial surgery as fillers or packing materials, and as biological chromatography supports. Its application towards delivery of macromolecules or protein drugs is discussed utilizing human serum albumin (HSA) as a model protein. (C) 1999 Kluwer Academic Publishers.
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    Differential Healing of Full Thickness Rabbit Skin Wound by Fibroblast Loaded Chitosan Sponge
    (JOURNAL OF BIOMATERIALS AND TISSUE ENGINEERING, 2013) Deepa, R; Paul, W; Anilkumar, TV; Sharma, CP
    For fabricating skin grafts with differential healing properties, enrichment with biomolecules/cells may be desirable. Earlier, we have developed a biomaterial-quality chitosan for biomedical application. Here we evaluated the wound healing potential of the chitosan-preparation and its variant, prepared by loading homologus fibroblast. Dermal fibroblasts isolated from rabbit skin were seeded on chitosan sponge to fabricate a homologous fibroblast loaded chitosan graft (HFLC). Full thickness excision wounds created on the rabbit dorsum were grafted with these two types of the chitosan sponges; naked or non cellular chitosan graft (NCC) and the homologous fibroblast loaded chitosan graft (HFLC). Post-graft skin-wound samples were examined histomorphologically at 7th, 14th and 21st day for evaluating the nature of the tissue reaction induced by the grafts. The wound healing parameters considered were the extent of re-epithelialisation, collagen deposition and angiogenesis, the thickness of epidermis, number of proliferating cells, vimentin positive cells and alpha smooth muscle actin cells. The results suggested that both the grafts aided wound healing but the HFLC induced a differential pattern of healing at 7 and 14 days featured by enhanced angiogenesis, desmoplasia and a hyperkeratotic dermis. Under therapeutic conditions, the HFLC may be useful for regulating the extent of collagen deposition in the early phases of a healing wound.
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    Fatty Acid Conjugated Calcium Phosphate Nanoparticles for Protein Delivery
    (INTERNATIONAL JOURNAL OF APPLIED CERAMIC TECHNOLOGY, 2010) Paul, W; Sharma, CP
    Calcium phosphate (CaP) nanoparticles with particle sizes < 100 nm were prepared and conjugated with lauric acid. This was achieved by first activating the phosphate group of CaP and conjugating it with lauric acid via acid chloride route incorporating chitosan as a spacer. Insulin was loaded and the nanoparticles were coated with alginate to impart pH-dependent sustained release. The released insulin was stable without alteration of the conformation of insulin and the particles were found to be noncytotoxic. Thus these CaP nanoparticles may be used as an excellent carrier for delivering protein drugs particularly insulin orally.
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    Green synthesis of gold nanoparticles with Zingiber officinale extract: Characterization and blood compatibility
    (PROCESS BIOCHEMISTRY, 2011) Kumar, KP; Paul, W; Sharma, CP
    Biosynthesis of gold nanoparticles with small size and biostability is very important and used in various biomedical applications. There are lot of reports for the synthesis of gold nanoparticles by the addition of reducing agent and stabilizing agent. In the present study we have synthesized gold nanoparticles, with a particle size ranging from 5 to 15 nm, using Zingiber officinale extract which acts both as reducing and stabilizing agent. Z. officinale extract is reported to be a more potent anti-platelet agent than aspirin. Therefore, green synthesis of gold nanoparticles with Z. officinale extract, as an alternative to chemical synthesis, is beneficial from its biological and medical applications point of view, because of its good blood biocompatibility and physiological stability. The formation and size distribution of gold nanoparticles were confirmed by dynamic light scattering (DLS), UV-vis spectrophotometer and transmission electron microscopy (TEM). Gold nanoparticles synthesized using citrate and Z. officinale extract demonstrated very low protein adsorption. Both nanoparticles were non platelet activating and non complement activating on contact with whole human blood. They also did not aggregate other blood cells, however, nanoparticles synthesised with Z. officinale extract was highly stable at physiological condition compared to citrate capped nanoparticles, which aggregated. Thus the usage of nanoparticles, synthesized with Z. officinale extract, as vectors for the applications in drug delivery, gene delivery or as biosensors, where a direct contact with blood occurs is justified. (C) 2011 Elsevier Ltd. All rights reserved.