Saturday, December 24, 2011

fungi in the synthesis of nanoparticle

The use of fungi in the synthesis of nanoparticle is a relatively recent addition to the list of microorganisms. The shift from bacteria to fungi as a means of developing natural “nanofactories” has the added advantage that downstream processing and handling of the biomass would be much simpler. The use of eukaryotes is potentially exiting since they secrete large amount of proteins, thus increasing productivity, and their easy usage in laboratory works is a suitable option in production of metallic nanoparticles among other microorganisms. More over the process can be easily scaled up, economically viable with the possibility of easily covering large surface areas by suitable growth of mycelia. Therefore, the present study has reported the biological process for the synthesis of silver nanoparticles extracellularly using R.stolonifer.
Rhizopus stolonifer showed maximum absorbance at 422nm. Parametric optimization study showed maximum absorbance at 40C and pH 7.0. Further characterization was made by UV-Visible
absorption spectroscopy which shows maximum absorption at 422 nm, Transmission Electron Microscope (TEM) revealed the formation of spherical nanoparticles with size ranging between 5 to 50 nm. Energy Dispersive Spectroscope (EDS) shows the optical absorption peak at 3kev, Fourier Transform Infrared (FT-IR) shows the bands at 1645(1), 1537(2) and 1454(3) cm-1. The biosynthesized silver nanoparticles have broad range of applications such as fluorescent biological labels, drug and gene delivery, bio detection of pathogens, detection of proteins, probing of DNA structure, tissue engineering, tumor destruction via heating, separation and purification of biological molecules and cells, and phagokinetic studies. Majority of the silver nanoparticle applications in medicine are geared towards drug delivery. Therefore, further work will be on antibacterial activity of silver nanoparticles.
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SYNTHESIS AND CHARACTERIZATION OF SILVER NANOPARTICLES BY RHIZOPUS STOLONIER

SYNTHESIS AND CHARACTERIZATION OF SILVER NANOPARTICLES BY RHIZOPUS STOLONIER

Biological synthesis of silver nanoparticles by using fungi is reported here. The present study is on screening of filamentous fungi for the production of silver nanoparticles extracellularly.
Eight fungi, Rhizopus.spp, Aspergillus terreus, A.flavus, A.niger, A.clavatus, Acremonium.spp, A.rutilum, Trichoderma.sp. have been screened for the production of silver nanoparticle. The fungal filtrates of the above said isolates were subjected to silver nitrate. After incubation, visual observation of brown color is an indication of silver nanoparticle production. Of the eight fungi, only one Rhizopus stolonifer showed maximum absorbance at 422nm. Parametric optimization study showed maximum absorbance at 400 C and pH 7.0. Further characterization was made by UV-Visible absorption spectroscopy which shows maximum absorption at 422 nm, Transmission Electron Microscope (TEM) revealed the formation of spherical nanoparticles with size ranging between 5 to 50 nm. Energy Dispersive Spectroscope (EDS) shows the optical absorption peak at 3kev, Fourier Transform Infrared (FT-IR) shows the bands at 1645(1), 1537(2) and 1454(3) cm-1.
UV-Visible absorption spectroscopy is one of the most widely used techniques for structural characterization of silver nanoparticles. In our experiment the maximum absorbance was observed at 422nm, implying that the bioreduction of the silver nitrate has taken place following incubation of the AgNO3 solution in the presence of cell-free extract. Our results are correlating with the reports of Sadowski, et al, (2008) and Maliszwaska, et.al., (2009) with the fungus Penicillium. Surface plasmon peak was located at 420 nm using klebsiella pneumonia (Minaeian et al 2008). Mukherjee et al, (2007) reported an intense peak at 410nm. It is reported that the absorption spectrum of spherical silver nanoparticles presents a maximum between 420nm and 450nm (Maliszewska 2008).
A representative TEM image recorded from drop coated film of a silver nanoparticles are spherical in shape. All the particles are well separated and no agglomeration was noticed. The size ranges between 5nm to30 nm was seen.
The process of growing silver nanoparticles comprises of two key steps:

(a) bioreduction of AgNO3 to produced
silver nanoparticles and
(b) stabilization and/or encapsulation of the same by
suitable capping agents 11. It is suggest that the biological molecules could possibly perform the function for the stabilization of the AgNPs. EDS analysis gives the additional evidence for the reduction of silver nanoparticles to elemental silver. The optical absorption peak is observed approximately at 3kev, which is typical for the absorption of metallic silver nanocrystals due to surface plasmon resonsnce, which confirms the presence of nanocrystalline elemental silver. Spectrum shows strong silver signal along with weak oxygen and carbon peak, which may be originate from the biomolecules that are bound to the surface of nanosilver particles.
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Ocular Inserts; Eye Infection; ophthalmic inserts

Abstract

Ocular drug delivery is one of the most fascinating and challenging tasks facing the Pharmaceutical researchers. One of the major barriers of ocular medication is to obtain and maintain a therapeutic level at the site of action for prolonged period of time. The eye as a portal for drug delivery is generally used for local therapy against systemic therapy to avoid the risk of eye damage from high blood concentration of the drug, which is not intended.

Keywords

Ocular Inserts; Eye Infection; ophthalmic inserts
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Ethosomes; Transdermal drug delivery; Ethosomal encapsulation; Ethosomes effects

Ethosomes; Transdermal drug delivery; Ethosomal encapsulation; Ethosomes effects

Ethosomes are soft, malleable vesicles and potential carrier for transportation of drugs. Ethosomes are characterized by simplicity in their preparation, safety and efficacy and can be tailored for enhanced skin permeation of active drugs. Ethosomes have been found to be much more efficient at delivering drug to the skin, than either liposomes or hydro alcoholic solution. Ethosomes have been tested to encapsulate hydrophilic drugs, cationic drugs, proteins and peptides. Ethosomal carrier opens new challenges and opportunities for the development of novel improved therapies.

Keywords
Ethosomes; Transdermal drug delivery; Ethosomal encapsulation; Ethosomes effects
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PHYTOCHEMICAL AND PRELIMINARY TOXICITY STUDY OF SESBANIA GRANDIFLORA (LINN.) FLOWERS

Sesbania grandiflora Linn. (Family : Fabaceae) is widespread distributed West Bengal, Assam, Karnataka and North-Eastern. The present study intended with various phytochemical screening and toxicity studies were carried out on the flowers of Sesbania grandiflora. Preliminary phytochemical evalution of the methanolic and aqueous extracts of revealed that presence of corbohydrate, proteins, amino acids, saponins, flavonoids, alkaloids, tannins and glycosides.The acute toxicity study were performed to determined LD50 ­ of 99% methanolic extract 20-40 mg/kg, 70% methanolic extract100-200 mg/kg and aqueous extract250-500 mg/kg.

Pandey Govind, Hepatogenic effect of some indigenous drugs on experimental liver damage. Phd thesis. Jabalpur, MP, India: JNKVV;1990

Kirthikar KR, Basu BD. Indian Medicinal plants Vol III. Dehradun: Bishen Singh Mahendra Pal Singh 1998: 735-36.

Das KC, Tripati AK.A new flavanol glycoside from Sesbania grandiflora (Linn.). Fitoterapia 1998; 69(5): 477-8

Asima Chatterjee, Satyesh Chandra Pakrashi. The Treatise on Indian Medicinal Plants Vol II. New Delhi: Publication and Information Directorate; 1992: 118

Mukherjee Pulok. k , “ Quality control of herbal drugs ”Business Horizons , 3-4, 2008

Jayaraman J. “Laboratory Manual in Biotechemistry. Published by birla publication New Delhi (I): 50-53, 1995.

Kar Ashutosh. “Pharmacognosy and Pharmabiotechnology.” Published by new age international, New Delhi (II): 147, 2007.

Singh S.P. “Practical Manual of Biochemistry.” (V) Published by CBS publishers & distributors New Delhi: 17-31, 2004.

Kokate CK, Ed. Practical Pharmacognosy. 4th ed. New Delhi: Vallabha Prakashan; 1999: 149-56.

Khandelwal KR. Practical Pharmacognosy techniques and experiments. 2nd ed. Pune: Nirali Prakashan; 2000: 149-56.

Mrs. Prema Veeraraghavan. Expert consultant, CPCSEA, OECD guideline No. 420.
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Bioelectronic DNA detection involves forming an electronic circuit mediated by nucleic acid hybridization and it serves as the basis for a DNA detection system called eSensor™ [1-4]. This system uses low-density DNA chips containing electrodes coated with DNA capture probes. Target DNA present in the sample hybridizes specifically both to capture probes and ferrocene labeled signal probes in solution thereby generating an electric current. Currente Sensor DNA chips contain as many as 36 electrodes for simultaneous detection of multiple pathogens from a single sample.

Many pathogens cause both acute and chronic disease at relatively low copy number and may be difficult or impossible to propagate in culture. Thus, most pathogen detection systems rely on nucleic acid amplification by using polymerase chain reaction (PCR). One highly effective amplification strategy targets conserved sequences among the family of organisms of interest. Such broad-range PCR strategies have been used to identify and characterize several known and previously uncharacterized bacteria [5,6] and viruses [7,8]. In order to maximize the utility of these effective pathogen nucleic acid amplification systems, amplification needs to be coupled with rapid, sensitive, and specific detection. Bioelectronic DNA detection by use of the eSensor chip might fulfill this need.

Human papillomaviruses (HPV) serve as an ideal model system for determining the efficiency and feasibility of eSensor DNA detection technology since there are at least 30 distinct genital HPV types that can be effectively amplified with broad-range consensus PCR primers. We designed two eSensor chips, each containing 14 probes specific for the conserved L1 region of the HPV genome. We evaluated clinical cervical cytology samples known to contain one or more HPV types. The eSensor DNA detection platform successfully detected the correct HPV type in most of these clinical samples, demonstrating that the system provides a rapid, sensitive, specific, and economical approach for multiple-pathogen detection and identification from a single sample.Background We used human papillomaviruses (HPV) as a model system to evaluate the utility of a nucleic acid, hybridization-based bioelectronic DNA detection platform (eSensor) in identifying multiple pathogens.