Quercetin impregnated chitosan-fibrin composite scaffolds as potential wound dressing materials - Fabrication, characterization and in vivo analysis.

The present study efforts at fabricating chitosan-fibrin composite (CF) scaffolds impregnated with quercetin for wound dressing application and aims at investigating their physicochemical properties. CF scaffolds were prepared by mixing acidic solution of chitosan with an alkaline solution of fibrin, to which quercetin (Q) was added, homogenized and lyophilized obtain Q-CF scaffold. FTIR spectra were used to determine the interactions between the functional groups of quercetin and CF scaffolds. TGA analysis revealed the decomposition of saccharide rings and amino acids of chitosan and fibrin at the temperature range of 255-400°C. Q-CF scaffold exhibited maximum tensile strength of 1.45MPa, an ideal mechanical strength for a wound dressing material. Q-CF scaffolds exhibited good bactericidal activity against Escherichia coli and Staphylococcus aureus. Biocompatibility of Q-CF scaffold was assessed using MTT assay, which elucidated its non-toxic property and excellent suitability for tissue engineering applications. In vivo wound healing experiments performed using albino rats revealed that topical application of Q-CF scaffold on open excision type of wounds can significantly accelerate the process of wound healing. These results suggest that Q-CF scaffold could serve as a promising wound dressing material.

Environmental benignity of a pesticide in soft colloidal hydrodispersive nanometric form with improved toxic precision towards the target organisms than non-target organisms.

Mosquito-borne diseases are of major concern as they cause devastating health effects, morbidity, and mortality in the human population. Conventional pesticides have failed to curb the mosquito population due to the development of insensitivity in mosquitoes. Hence, higher dosages of pesticides along with their toxic solubilizers have been employed, which have led to raise in pesticide pollution load, environmental toxicity, and human health concerns. As a realisation for the requirement of alternative pesticides, the present study has involved in the formulation of a hydrodispersive nanometric colloidal form of deltamethrin (NDM), a type-II pyrethroid pesticide, from its hydroimmisicible parental form (PDM). The mean hydrodynamic diameter of the droplets was found to be 30.6±4.6nm by dynamic light scattering study (DLS). High-resolution transmission electron micrographs have revealed the spherical structure of the droplets with a size range of 35-40nm. The NDM was found to possess sedimentation resistance, intrinsic and hydrodispersive stability. The toxicity of NDM and PDM was comparatively investigated on target organisms (Culex tritaeniorhynchus and Culex quinquefasciatus mosquitoes) and non-target organisms (Allium cepa - Bioindicator of toxicants and Rhizobium sp. - Soil bacteria). As comparative to PDM, NDM has exerted higher efficacy on adult mosquito and larval population, even at low-level concentrations. However, in the case of non-target organisms, the NDM toxicity was lower than PDM. Comprehensively, the study has concluded the potential advantage of formulating conventional pesticides into nanometric soft colloidal form for the improved toxic precision on target organisms (mosquitoes). This ensures the ability of NDM to combat against the mosquito population even at lower concentrations, thereby reducing the pesticide exposure load towards the environment and human population.

Chitosan-Fibrin Nanocomposites as Drug Delivering and Wound Healing Materials.

In the present study, chitosan-fibrin nanocomposites (CFNs) were prepared using a novel method and analysed for their physico-chemical properties. TEM and SEM studies revealed their size in the range of 24-28 nm with zeta potential value of + 16 mV. Anti-bacterial activity of CFN was investigated against Escherichia coli and Staphylococcus aureus. For drug delivery applications, 71% of methotrexate (MTX) was entrapped in CFNs that displayed sustained release for up to 96 h. Anti-cancer activity of MTX-CFN was evaluated on HeLa and MCF 7 cells, which showed dose-dependent toxicity on both the cell lines. Further, the role of CFN in wound healing was studied by creating open excision wounds on albino rats. Topical application of CFN, once in two days, for up to 10 days resulted in complete healing of wounds on day 14 whereas it took 22 days in control. Histological and biochemical analyses proved increased synthesis of collagen with active migration of fibroblasts and epithelial cells in CFN treated wounds. From our study, it is proposed that CFN may be used as a suitable candidate for drug delivery and wound healing applications.

Time-dependent biodistribution, clearance and biocompatibility of magnetic fibrin nanoparticles: an in vivo study.

Recently, bioretention and toxicity of injected nanoparticles in the body has drawn much attention in biomedical research. In the present study, 5 mg Fe per kg body weight of magnetic fibrin nanoparticles (MFNPs) were injected into mice intravenously and investigated for their blood clearance profile, biodistribution, haematology and pathology studies for a time period of 28 days. Moderately long circulation of MFNPs in blood was observed with probable degradation and excretion into the bloodstream via monoatomic iron forms. Inductively coupled plasma optical emission spectrometry (ICP-OES) and Prussian blue staining results showed increased accumulation of MFNPs in the liver, followed by spleen and other organs. Body weight, spleen/thymus indexes, haematology, serum biochemistry and histopathology studies demonstrated that MFNPs were biocompatible. These results suggest the feasibility of using MFNPs for drug delivery and imaging applications.

Synthesis, characterization and evaluation of collagen scaffolds crosslinked with aminosilane functionalized silver nanoparticles: in vitro and in vivo studies.

This work presents a novel approach for functionalization of silver nanoparticles (AgNPs) and cross-linking them with collagen to form collagen based scaffolds with enhanced medical applications. Functionalized AgNPs of size 10-50 nm were synthesized and confirmed by using UV-vis, fluorescence spectroscopy and particle size analysis. Stable nano-sized particles were functionalized and cross-linked with succinylated collagen (SC) and lyophilized to form functionalized silver nanoparticles cross-linked with succinylated collagen (FSCSC) scaffolds. The prepared scaffolds, viz., SC and FSCSC, were characterized using the following techniques: Fourier transform infrared spectroscopy, circular dichroism, differential scanning calorimetry, thermogravimetric analysis, X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy and transmission electron microscopy. The thermal analyses results suggest that FSCSC scaffolds are more stable than collagen and SC scaffolds. Moreover, FSCSC scaffolds show improved tensile strength, which is essential for wound healing purposes. The FSCSC showed lower minimum inhibitory concentration (MIC) values compared to AgNPs impregnated in the SC scaffold for both gram positive and negative bacterial strains, which indicated that FSCSC have improved antibacterial efficacy compared to the latter and can be utilized for biomedical applications. Furthermore, the in vitro and in vivo studies suggest that the FSCSC scaffold can be used as a wound dressing material for clinical applications.

Fabrication of collagen scaffolds impregnated with sago starch capped silver nanoparticles suitable for biomedical applications and their physicochemical studies.

The present investigation attempts at fabricating collagen-based scaffolds impregnated with sago starch capped silver nanoparticles (AgNPs), useful for biomedical applications, and aims at studying their physicochemical aspects. AgNPs synthesized through a chemical reduction method, capped using different concentrations of sago starch, are incorporated into collagen derived from fish scales, and lyophilized to form scaffolds. FT-IR spectra confirm and validate the interaction of sago starch capped AgNPs with collagen in the scaffolds. TGA and DSC results indicate enhanced thermal stability of collagen scaffolds impregnated with sago capped AgNPs compared to collagen alone. All the collagen scaffolds containing sago starch capped AgNPs show high tensile strength values for their use as wound dressing materials. Moreover, lower minimum inhibitory concentration values are obtained for the above capped AgNP collagen scaffolds, which indicate higher antibacterial activities compared to uncapped AgNPs tested against both gram positive and negative bacterial strains. The novelty is that the developed scaffolds are biodegradable and in vitro studies reveal them as biocompatible and suitable for tissue regeneration applications.

Physiologically clotted fibrin--preparation and characterization for tissue engineering and drug delivery applications.

Fibrin used for biomedical applications is prepared by mixing concentrated solutions of fibrinogen and thrombin in presence of cross-linking agents such as Factor XIII or glutaraldehyde. The main drawbacks associated with this procedure include cost, complexity and time required for fibrin preparation. Hence, present study deals with the characterization of physiologically clotted fibrin (PF) for bone tissue engineering and drug delivery applications. For this the physico-chemical properties of PF were compared with those of the conventionally prepared fibrin (CF). Further MTT and haemolytic assays were performed for both PF and CF to compare their biocompatibility. The amount of alkaline phosphatase produced and calcium secreted by MG-63 cells in the presence of PF and CF were used to relate the osteogenic potency of PF with that of CF. Gallic acid, an anti-cancer drug was loaded within PF and CF and their role in drug delivery was compared.

Deposition of superparamagnetic nanohydroxyapatite on iron-fibrin substrates: preparation, characterization, cytocompatibility and bioactivity studies.

In the present study, nanosized hydroxyapatite (nHAp) was formed on iron-fibrin substrates and its physico-chemical properties were characterized. The prepared iron-fibrin-nanohydroxyapatite (IF-nHAp) composite was needle shaped with an average width of about 30nm and length of 80nm. The vibrating sample magnetometer (VSM) was used to evaluate the superparamagnetic behavior of the nanocomposite, IF-nHAp. Hemolysis and ELISA (enzyme linked immunosorbent assay) were performed to evaluate the its bio/immunocompatibility and MTT (3-(4,5-dimethylazol-2-yl)-2,5-diphenyl-tetrazolium bromide) assay using osteoblast cells was performed to scrutinize its proliferative potential. Alkaline phosphatase activity (ALP) and calcium deposition were studied to investigate the osteogenic property of the nanocomposite. RT-PCR (real time-polymerase chain reaction) was used to quantify the mRNA levels of ALP, OC (osteocalcin), and OPN (osteopontin) genes involved in the osteogenic differentiation and matrix mineralization. Further, the bone bonding ability of IF-nHAp was observed by the deposition of apatite layers on the composite incubated in simulated body fluid (SBF).

Fibrin nanoparticles as Possible vehicles for drug delivery.

BACKGROUND: Several issues have been raised emphasizing the harmful toxic effects of metal nanoparticles towards biological systems. Search of biological nanoparticles with excellent biocompatibility and bioavailability could address this problem. METHODS: Fibrin nanoparticles (FNP) were prepared using a novel technique and characterized for their physico-chemical properties. In vitro studies were performed to examine cytotoxicity and cellular uptake of FNP. Innate immune response to FNP was studied by (i) estimating in vitro generation of complement split products, C3a and C4d and (ii) in vivo expression of pro-inflammatory cytokines, TNF-α, IL-1 and IL-6. In vivo biodistribution study was carried out by intravenous administration of FITC-labelled FNP in mice. RESULTS: FNP were spherical with size ranging from 25 to 28nm. In vitro studies proved the biocompatibility of the nanoparticles, with their distribution across the cytoplasm and nucleus of treated cells. Complement activation studies showed insignificant increase in the level of C3a when compared with positive control. RT-PCR results revealed significant upregulation of TNF-α and downregulation of IL-6 cytokines after 6h of FNP administration. In vivo biodistribution studies showed moderate blood circulation time, with predominant distribution of nanoparticles in the liver followed by the lungs, kidney and spleen. Haematology, serum biochemistry, and histopathology analyses demonstrated that FNP were non-toxic. CONCLUSION: Owing to their small size, low cost, ease of preparation and excellent biocompatibility, FNP might be a promising novel material for drug delivery applications. GENERAL SIGNIFICANCE: Our results demonstrate the safe and promising use of FNP for biomedical applications.

Preparation, characterization and evaluation of a biopolymeric gold nanocomposite with antimicrobial activity.

The present study describes the antimicrobial activity of C-AuNp-Amp (chitosan-capped gold nanoparticles coupled with ampicillin). C-AuNp-Amp was synthesized using the wet precipitation method and characterized using FTIR (Fourier-transform IR) spectroscopy and AFM (atomic force microscopy) techniques. The optimal level of ampicillin concentration that couples with the C-AuNp nanocomposite was determined by using UV-visible spectroscopy. The agar-well diffusion method was used to evaluate the antimicrobial activity, and the broth dilution assay was used to determine the MIC (minimum inhibitory concentration). The size of the ellipsoidal C-AuNp-Amp particles was found to be in the range of 50-100 nm. The FTIR spectrum confirms the bonding between amino groups of chitosan and carboxylic groups of ampicillin. The maximum coupling of ampicillin with C-AuNp was found to be 4.07 mg/10 ml. These results revealed the antimicrobial efficacy of C-AuNp-Amp and a 2-fold increase in activity was achieved when compared with that of free ampicillin. By reducing the antibiotic dosage to 50%, the side effects produced by antibiotics can be minimized.