Effect of process variables on particle size and viability ofBifidobacterium lactisBb-12 in genipin-gelatin microspheres

Gelatin microspheres cross-linked with genipin were developed to encapsulate the probiotic Bifidobacterium lactis Bb-12 The effects of different gelatin concentrations (10-19% w/v), bloom strengths (175 and 300), surfactants, stirring rates during emulsion formation and genipin concentrations (0-10 mM) on the microsphere sizes and viability of bacterial cells were investigated. Principal Component Analysis revealed microsphere size distribution differed depending on the presence or absence of surfactants as well as a trend of increasing micropshere size with increasing gelatin concentration and bloom strength. Lower stirring rates resulted in larger microspheres with higher encapsulation yields of bifidobacteria Microsphere size and cell viability were not significantly (p < 0.05) influenced by increasing genipin concentrations up to 10 mM whereas microsphere stability in simulated gastric juice increased with increasing genipin concentration. The encapsulation yields were higher in 175 bloom strength gelatin microspheres than in 300. Cold-stage scanning electron microscopy showed encapsulated bacteria distributed throughout the genipin cross-linked gelatin matrix.

Effect of the major glycosides of Harpagophytum procumbens (Devil's Claw) on epidermal cyclooxygenase-2 (COX-2) in vitro

Harpagophytum procumbens, commonly known as Devil's Claw, is indigenous to southern Africa, and extracts of the tubers have been used for centuries in the treatment of a variety of inflammatory disorders. Its major active components, harpagoside (1), harpagide (2), 8-coumaroylharpagide (3), and verbascoside (4), are believed to interact either synergistically or antagonistically in modulating the enzymes responsible for inducing inflammation, although this has not been probed hitherto. In the current work, the ability of these compounds to inhibit the expression of COX-2 following administration to freshly excised porcine skin has been investigated. An ethanol-soluble extract of H. procumbens tubers and two of the pure compounds tested showed promising activity in Western blotting and immunocytochemical assays, with harpagoside (1) and 8-coumaroylharpagide (3) exhibiting greater reductions in COX-2 expression than verbascoside (4). Harpagide (2) caused a significant increase in the levels of COX-2 expression after 6 h of topical application. The data suggest that the efficacy of H. procumbens is dependent upon the ratios of compounds 1-4 present, which is inconsistent with some current official monograph specifications based solely on harpagoside (1) content.

Evaluation of antiprotozoal and antimycobacterial activities of the resin glycosides and the other metabolites of Scrophularia cryptophila

Resin glycosides are secondary metabolites exclusive to the convolvulaceous plants. In this study, crypthophilic acids A-C (1-3), the first resin glycosides occurring in another family (Scrophulariaceae), and the other constituents of Scrophularia cryptophila were examined for in vitro antiprotozoal and antimycobacterial potentials. Except for crypthophilic acid B (2), all tested compounds exhibited growth-inhibitory effect against Trypanosoma brucei rhodesiense, with l-tryptophan (6) and buddlejasaponin III (7) being the most potent ones (IC(50)'s 4.1 and 9.7 microg/ml). In contrast, the activity towards Trypanosoma cruzi was poor, and only crypthophilic acid C (3), 6 and 7 were trypanocidal at concentrations above 40 microg/ml. With the exception of 2 and 6, all compounds were active against Leishmania donovani. Harpagide (4) and 3 emerged as the best leishmanicidal agents (IC(50)'s 2.0 and 5.8 microg/ml). Only compounds 3, 6 and 7 showed antimalarial activity against Plasmodium falciparum with IC(50) values of 4.2, 16.6 and 22.4 microg/ml. Overall the best and broadest spectrum activity was presented by compounds 3 and 7, as they inhibited all four parasitic protozoa. None of the isolates had significant activity against Mycobacterium tuberculosis (MICs >100 microg/ml) or were toxic towards mammalian (L6) cells. This is the first report of antiprotozoal activity for natural resin glycosides, as well as for harpagide (4), acetylharpagide (5), tryptophan (6) and buddlejasaponin III (7).

[Study on the temporal change of properties of genipin crosslinked gelatin]

Investigated the changes of crosslinking index, swelling ratio, degradation rate and cytotoxicity of genipin crosslinked gelatin accompany with crosslinking time. 1% genipin crosslinked gelatin were divided into 7 groups by crosslinking time: 10 min group, 30 min group, 1 h group, 2 h group, 12 h group, 24 h group, 72 h group. The results proved that genipin could crosslink gelatin effectively. Accompany with increasing of crosslinking time, crosslinking index increased, and swelling ratio, degradation rate decreased. In 10 min group, crosslinking index was low(26.7%), swelling ratio was high, (265%), completely degraded within 1 week. This indicated that biomaterials of 10 min group was instable and degraded easily. Compared with 10 min group, biomaterials of 30 min group changed significantly with crosslinking index(45.7%), swelling ratio (206%) and degration rate (completely degraded between 4 weeks and 8 weeks). This indicated that genipin could change the properties of gelatin within 30 min. Biomaterials after 30 min, crosslinking index increased, and swelling ratio, degradation rate decreased gradually accompanied with increasing of crosslinking time. Biomaterials of 72 h, crosslinking index was 73.1%, swelling ratio was 152%, and degradated 18.9% after 12 weeks. RGR (relative cell growth rate) of every group measured by MTT assay changed between 87.9% and 105.4%, indicated that the cytotoxicity of genipin crosslinked gelatin was very low.

Genipin-crosslinked chitosan/gelatin blends for biomedical applications

Blends between chitosan (CS) and gelatin (G) with various compositions (CS/G 0/100 20/80, 40/60, 60/40 100/0 w/w) were produced, as candidate materials for biomedical applications. Different amounts of genipin (0.5 wt.% and 2.5 wt.%) were used to crosslink CS/G blends, promoting the formation of amide and tertiary amine bonds between the macromolecules and the crosslinker. The effects of composition and crosslinking on the physico-chemical properties of samples were evaluated by infrared analysis, thermogravimetry, contact angle measurements, dissolution and swelling tests. Mechanical properties of crosslinked samples were also determined through stress-strain and creep tests: samples stiffness increased with increasing the crosslinker amount and the CS content. Blend composition affected mouse fibroblasts adhesion and proliferation on substrates, depending on the crosslinker amount. Finally, crosslinked CS/G blends containing 80 wt.% G were found to support neuroblastoma cells adhesion and proliferation which made them promising candidates for uses in the field of nerve regeneration.

[The role of mitochondrial uncoupling proteins in the development of changes of endothelium-dependent reactions of the heart and vessels in experimental diabetes mellitus]

The influence of mitochondrial uncoupling protein genipin on endothelium-dependent reaction of vessels, heart contractility and myocardial oxygen consumption was studied at streptozotocin-induced rat model of diabetes mellitus. The partial restoration of damaged at diabetes mellitus vascular reactions as well as decrease ofmyocardial oxygen consumption has been shown after intraperitoneal injection of genipin. For example, after the introduction of 10 mg/kg genipin were shown a partial restoration of endothelium-dependent dilatation of aorta and coronary vessels, increase of contractive strength-dependent responses of vascular smooth muscle, decrease of portal vein isolated strips stiffness, the improvement of contractive properties and decrease of myocardial stiffness. These data suggest a possible role for mitochondrial uncoupling protein in the development of changes of heart and vascular responses observed at experimental diabetes mellitus.

Immobilization of drugs for glaucoma treatment

Recently there have been some developments in the preparation of controlled drug delivery systems for glaucoma. Many materials are being used in this area, namely gelatine and chitosan. Both of them present high levels of biocompatibility and biodegradability. In this paper, we wish to report the work we have been doing on the preparation and characterization of hydrogels based on gelatine and chitosan. The crosslinking agents used were 1-(3-(Dimethylamino)propyl)-3-Ethylcarbodiimide hydrocholide (CDI), 1,4-Butanodiol diglycidyl ether (epoxyde 1), Ethylene glycol diglycidyl ether (epoxyde 2) and genipin. The results obtained showed that all of the films were hydrogels. The surface and transversal cut showed a porous surface in all the films. The thermal analysis proved the modifications in the polymeric chains, with the stabilization of all of them by the crosslinking agents. The release pattern indicates that the gelatine films were the best since they release the adequate proportion of drug. Finally, the cytotoxicity showed that the gelatine films were all biocompatible, specially the ones crosslinked with one of the Epoxydes.

Mixed lineage kinase 3 connects reactive oxygen species to c-Jun NH2-terminal kinase-induced mitochondrial apoptosis in genipin-treated PC3 human prostate cancer cells

It has been reported that genipin, the aglycone of geniposide, induces apoptotic cell death in human hepatoma cells via a NADPH oxidase-reactive oxygen species (ROS)-c-Jun NH(2)-terminal kinase (JNK)-dependent activation of mitochondrial pathway. This continuing work aimed to define that mixed lineage kinase 3 (MLK3) is a key mediator, which connect between ROS and JNK in genipin-induced cell death signaling. In PC3 human prostate cancer cells, genipin stimulated MLK3 activity in concentration- and time-dependent manner. The PC3 cells stably transfected with dominant-negative form of MLK3 was less susceptible to population of the sub-G1 apoptotic cells, activation of caspase, collapse of mitochondrial membrane potential, and release of cytochrome c triggered by genipin, suggesting a crucial role of MLK3 in genipin signaling to apoptotic cell death. Diphenyleneiodonium (DPI), a specific inhibitor of NADPH oxidase, markedly inhibited ROS generation and MLK3 phosphorylation in the genipin-treated cells. Pretreatment with SP0600125, a specific inhibitor of JNK but neither U0126, a specific inhibitor of MEK1/2 nor PD169316, a specific inhibitor of p38 suppressed genipin-induced apoptotic cell death. Notably, both the phosphorylation of JNK and induction of c-Jun induced by genipin were markedly inhibited in PC3-EGFP-MLK3 (K144R) cells expressing a dominant-negative MLK3 mutant. Taken together, our observations suggest genipin signaling to apoptosis of PC3 cells is mediated via activation of ROS-dependent MLK3, which leads to downstream activation of JNK.

Noninvasive nuclear factor-κB bioluminescence imaging for the assessment of host–biomaterial interaction in transgenic mice

The inflammatory response is a key component in the biocompatibility of biomaterials. Among the factors that control the development of inflammation is a critical molecule nuclear factor-kappaB (NF-kappaB). Therefore, the aim of this study was to assess the feasibility of noninvasive whole-body real-time imaging for the evaluation of host-biomaterial interaction in the NF-kappaB transgenic mice. Transgenic mice, carrying the luciferase gene under the control of NF-kappaB, were constructed. In vivo bioluminescence imaging showed that the constitutive and induced NF-kappaB activities of transgenic mice were detected in most of the lymphoid tissues, demonstrating that NF-kappaB-driven luminescence reflected the inflammatory response in vivo. By the implantation of genipin-cross-linked gelatin conduit (GGC) and bacterial endotoxin-immersed GGC in the dorsal region, we detected a strong and specific luminescent signal from the tissue around the bacterial endotoxin-immersed GGC implant. Histological and immunohistochemical analysis also demonstrated that inflammation, characterized by the infiltration of immune cells, the accumulation of fluid, and the activation of NF-kappaB, was evoked around the same region. The correlation between the bioluminescence imaging and histological changes indicated that noninvasive imaging technique could be used to monitor the real-time inflammation in the implanted mice.

A fibrinogen-based precision microporous scaffold for tissue engineering

Fibrin has been long used as an effective scaffolding material to grow a variety of cells and tissue constructs. It has been utilized mainly as a hydrogel in varying concentrations to provide an environment in which suspended cells work to rearrange the fibers and lay down their own extracellular matrix. For these fibrin hydrogels to be useful in many tissue-engineering applications, the gels must be cultured for long periods of time in order to increase their mechanical strength to the levels of native tissues. High concentrations of fibrinogen increase the mechanical strength of fibrin hydrogels, but at the same time reduce the ability of cells within the scaffold to spread and survive. We present a method to create a microporous, nanofibriliar fibrin scaffold that has controllable pore size, porosity, and microstructure for applications in tissue engineering. Fibrin has numerous advantages as a scaffolding material as it is normally used by the body as temporary scaffolding for tissue regeneration and healing, and can be autologously sourced. We present here a scaffolding process which enhances the mechanical properties of the fibrin hydrogel by forming it surrounding poly(methyl-methacrylate) beads, then removing the beads with acetone to form an interconnected microporous network. The acetone serves the dual purpose of precipitating and fixing the fibrinogen-based scaffolds as well as adding strength to the network during polymer bead removal. Effects of fibrinogen concentration and time in acetone were examined as well as polymerization with thrombin. A natural crosslinker, genipin, was also used to add strength to the scaffolds, producing a Young's modulus of up to 184+/-5 kPa after 36 h of reaction. Using these methods we were able to produce microporous fibrin scaffolds that support cell growth and have mechanical properties similar to many native tissues.

Glucose sensing by POMC neurons regulates glucose homeostasis and is impaired in obesity

A subset of neurons in the brain, known as 'glucose-excited' neurons, depolarize and increase their firing rate in response to increases in extracellular glucose. Similar to insulin secretion by pancreatic beta-cells, glucose excitation of neurons is driven by ATP-mediated closure of ATP-sensitive potassium (K(ATP)) channels. Although beta-cell-like glucose sensing in neurons is well established, its physiological relevance and contribution to disease states such as type 2 diabetes remain unknown. To address these issues, we disrupted glucose sensing in glucose-excited pro-opiomelanocortin (POMC) neurons via transgenic expression of a mutant Kir6.2 subunit (encoded by the Kcnj11 gene) that prevents ATP-mediated closure of K(ATP) channels. Here we show that this genetic manipulation impaired the whole-body response to a systemic glucose load, demonstrating a role for glucose sensing by POMC neurons in the overall physiological control of blood glucose. We also found that glucose sensing by POMC neurons became defective in obese mice on a high-fat diet, suggesting that loss of glucose sensing by neurons has a role in the development of type 2 diabetes. The mechanism for obesity-induced loss of glucose sensing in POMC neurons involves uncoupling protein 2 (UCP2), a mitochondrial protein that impairs glucose-stimulated ATP production. UCP2 negatively regulates glucose sensing in POMC neurons. We found that genetic deletion of Ucp2 prevents obesity-induced loss of glucose sensing, and that acute pharmacological inhibition of UCP2 reverses loss of glucose sensing. We conclude that obesity-induced, UCP2-mediated loss of glucose sensing in glucose-excited neurons might have a pathogenic role in the development of type 2 diabetes.

Preparation and evaluation of ketorolac tromethamine gel containing genipin for periodontal diseases

Ketorolac tromethamine gel (KT gel) and ketorolac tromethamine gel containing genipin (KTG gel) were prepared and their therapeutic effects on periodontitis were evaluated. The skin permeation rate of ketorolac from the KT gel and KTG gel was 5.75+/-0.53 and 5.82 +/- 0.74 microg/cm2/ h, respectively. The skin permeation rate of genipin from the KTG gel was 10.13 +/- 1.47 microg/ cm2/h. The tensile strength of the KTG gel was larger than the KT gel. After 4 weeks, the periodontal pocket depth of the KTG gel group (3.22 +/- 0.20 mm) significantly decreased compared with the non-treated group (4.50 +/- 0.25 mm) and the KT group (3.84 +/- 00.26 mm). The KTG gel did not induce separation of the stratum corneum and subcutaneous tissue, and the collagen layers of the corium were closer, more fibrous, and showed longer connections than in the other groups. The KTG gel appears to be effective against gingivitis in the periodontal pocket through its increased anti-inflammatory activity and the crosslinking of genipin with the biological tissue.

Gelatin microspheres encapsulated with a nonpeptide angiogenic agent, ginsenoside Rg1, for intramyocardial injection in a rat model with infarcted myocardium

Angiogenic therapies may need to select a stable agent to be delivered. In the study, a nonpeptide angiogenic agent, ginsenoside Rg(1) (Rg(1)), was encapsulated in the gelatin microspheres (MSs) crosslinked with genipin and intramuscularly injected into a rat model with infarcted myocardium. bFGF was used as a control. After swelling in an aqueous environment, the MSs without crosslinking became collapsed and stuck together. For those crosslinked, the swollen MSs appeared to be more stable with an increasing the degree of crosslinking. After it was released from MSs in vitro, the remaining activity of bFGF on HUVEC proliferation reduced significantly, while that of Rg(1) remained constant. An inspection of the retrieved hearts revealed a large aneurysmal left ventricle (LV) with a thinned myocardium and a significant myocardial fibrosis for that treated with the Empty MSs (without drug encapsulation). However, those receiving the MSs encapsulated with bFGF or Rg(1) attenuated the enlargement of the LV cavity and the development of myocardial fibrosis. The densities of microvessels found in the border zones of the infarct treated with the bFGF or Rg(1) MSs were significantly greater than that treated with the Empty MSs. These results indicated that Rg(1), a stable angiogenic agent, successfully enhanced the myocardial perfusion and preserved the infarcted LV function.

Constituents of Gardenia volkensii: their brine shrimp lethality and DPPH radical scavenging properties

The seeds and the pulp of Gardenia volkensii yielded one new iridiod, namely 4-(2N-gardenamide)n-butanoic acid, together with the known iridoids genipin and genipin gentiobioside, the pterocarpin medicarpin, coumarins, phenylpropanoids, benzenoids and triterpenes. The structures of these were determined on the basis of spectroscopic data and by comparison of obtained data with those from literature. The fruit extracts of this plant exhibited moderate radical scavenging activity against DPPH radical and moderate lethality against brine shrimps (Artemia salina).

Effect of genipin, a naturally occurring crosslinker on the properties of kappa-carrageenan

Genipin-fixed kappa-carrageenan was prepared in ambient conditions in aqueous solution using genipin, a naturally occurring crosslinker with kappa-carrageenan (kappaC). The crosslinked kappaC showed the greatest swelling capacity in acidic medium having pH 1.2 when compared to those in neutral and alkaline media. Enhanced stability of the crosslinked product with respect to the non-modified kappaC was confirmed by degradation studies in Ringer's solution, rheological and thermogravimetric measurements. Genipin fixation of kappaC was confirmed by measuring the bulk density, true density, pore volume, porosity, intrinsic viscosity, UV absorbance and optical rotation of the crosslinked kappaC, and as well as by optical microscopy, SEM, and MS/MS studies. The crosslinked product may be useful as super absorbent and sustained release formulation in biomedical applications.

In vitro and in vivo tissue repair with laser-activated chitosan adhesive

BACKGROUND AND OBJECTIVES

Sutures are currently the gold standard for wound closure but they are still unable to seal tissue and may induce scarring or inflammation. Biocompatible glues, based on polysaccharides such as chitosan, are a possible alternative to conventional wound closure. In this study, the adhesion of laser-activated chitosan films is investigated in vitro and in vivo. In particular we examine the effect of varying the laser power, as well as adding a natural cross-linker (genipin) to the adhesive composition.

STUDY DESIGN/MATERIALS AND METHODS

Flexible and insoluble strips of chitosan films (surface area approximately 34 mm(2), thickness approximately 20 microm) were bonded to sheep intestine using several laser powers (0, 80, 120, and 160 mW) at 808-nm wavelength. The strength of repaired tissue was tested by a calibrated tensiometer to select the best power. A natural cross-linker (genipin) was also added to the film and the tissue repair strength compared with the strength of plain films. The adhesive was also bonded in vivo to the sciatic nerve of rats and the thermal damage induced by the laser assessed 4 days post-operatively.

RESULTS

Chitosan adhesives successfully repaired intestine tissue, attaining a maximum repair strength of 14.7+/-4.3 kPa (n = 30) at the laser power of 120 mW. The chitosan-genipin films achieved lower repair strength (9.1+/-2.9 kPa). The laser caused partial demyelination of axons at the site of operation, but the myelinated axons retained a normal morphology proximally and distally.

CONCLUSIONS

The chitosan adhesive effectively bonded to tissue causing only localized thermal damage in vivo, when the appropriate laser parameters were selected.

Immobilization of Lipase to Chitosan Beads using a Natural Cross‐Linker

Genipin, a reagent of plant origin was used for the immobilization of lipase by cross-linking to chitosan beads. The catalytic properties and operational and storage stabilities of the immobilized lipase were compared with the soluble lipase. Under optimum conditions, 198 microg protein was bound per g chitosan with a protein-coupling yield of 35%. The hydrolytic activity was 10.8 U/g chitosan and the relative specific activity was 108%. The immobilized lipase showed better thermal and pH stabilities compared to the soluble form. The immobilized enzyme exhibited mass transfer limitations as reflected by a higher apparent K(m) value and a lower energy of activation. The immobilized enzyme retained about 74% of its initial activity after five hydrolytic cycles.

Inchinkoto, a herbal medicine, and its ingredients dually exert Mrp2/MRP2-mediated choleresis and Nrf2-mediated antioxidative action in rat livers

Inchinkoto (ICKT), a herbal medicine, has been recognized in Japan and China as a "magic bullet" for jaundice. To explore potent therapeutic agents for cholestasis, the effects of ICKT or its ingredients on multidrug resistance-associated protein 2 (Mrp2/ MRP2)-mediated choleretic activity, as well as on antioxidative action, were investigated using rats and chimeric mice with livers that were almost completely repopulated with human hepatocytes. Biliary excretion of Mrp2 substrates and the protein mass, subcellular localization, and mRNA level of Mrp2 were assessed in rats after 1-wk oral administration of ICKT or genipin, a major ingredient of ICKT. Administration of ICKT or genipin to rats for 7 days increased bile flow and biliary excretion of bilirubin conjugates. Mrp2 protein and mRNA levels and Mrp2 membrane densities in the bile canaliculi and renal proximal tubules were significantly increased in ICKT- or genipin-treated rat livers and kidneys. ICKT and genipin, thereby, accelerated the disposal of intravenously infused bilirubin. The treatment also increased hepatic levels of heme oxygenase-1 and GSH by a nuclear factor-E2-related factor (Nrf2)-dependent mechanism. Similar effects of ICKT on MRP2 expression levels were observed in humanized livers of chimeric mice. In conclusion, these findings provide the rationale for therapeutic options of ICKT and its ingredients that should potentiate bilirubin disposal in vivo by enhancing Mrp2/MRP2-mediated secretory capacities in both livers and kidneys as well as Nrf2-mediated antioxidative actions in the treatment of cholestatic liver diseases associated with jaundice.

Inhibition of the pro-inflammatory mediators' production and anti-inflammatory effect of the iridoid scrovalentinoside

We have studied scrovalentinoside, an iridoid with anti-inflammatory properties isolated from Scrophularia auriculata ssp. pseudoauriculata, as an anti-inflammatory agent in different experimental models of delayed-type hypersensitivity. We found that scrovalentinoside reduced the edema induced by oxazolone at 0.5 mg/ear and sheep red blood cells at 10 mg/kg. The observed effect occurred during the last phase or inflammatory response; during the earlier phase or induction of the delayed-type hypersensitivity reaction, no significant activity was noted. Thus, scrovalentinoside reduced both the edema and cell infiltration in vivo and reduced lymphocyte proliferation in vitro, affecting the cycle principally during the first 48 h. Whereas cells stimulated with phytohemagglutinin changed from the G(0)/G(1) phase to the S and G(2)/M phases, when these same cells were treated with scrovalentinoside (100 microM), they remained in the G(0)/G(1) phase. Finally, scrovalentinoside inhibited the production of the pro-inflammatory mediators' TNF-alpha, IFN-gamma, IL-1beta, IL-2, IL-4, LTB(4), and NO, but had no effect on the production of the anti-inflammatory cytokine IL-10.

Density quantification of collagen grafted on biodegradable polyester: Its application to esophageal smooth muscle cell

An improved technique for quantification of collagen immobilized on polymeric substrates is needed as tissue engineering evolves. Current immobilized protein quantification methods are indirect, time-consuming, and/or inaccurate. In this study, Sirius red colorimetric microassay was shown to be feasible for quantifying the density of collagen immobilized on aminolyzed poly(L-lactic acid) (PLLA) surfaces using the specific bonding of Sirius dye to collagen. It offers a number of advantages over traditional methods, including direct staining, high sensitivity, and high stability of the dye. The detection limit is approximately 0.1 microg/cm(2), and the dynamic range is greater than 50. Sirius red dye has not been used previously for quantification of protein immobilized on polymers. The collagen densities achieved with each of the two crosslinking reagents investigated, namely glutaraldehyde (GA) and genipin, were compared. The latter is an alternative crosslinker derived from a traditional Chinese medicine. The collagen densities immobilized by the two reagents were measured to be similar. This was confirmed by the similar behaviors of esophageal primary smooth muscle cells (ESMCs) on these two modified PLLA membranes; collagen grafted with either coupler was found to greatly promote, to a similar extent, cell attachment and both short-term (4 days) and long-term (12 days) proliferation compared with unmodified PLLA. Smooth muscle cells on both modified membranes were stained to display contractile alpha-actin protein filaments.

Fingerprint Reagents with Dual Action: Color and Fluorescence

We define "dual fingerprint reagents" as chemical formulations that produce with latent fingerprints in one stage impressions that are both colored and fluorescent. Solutions containing ninhydrin and group IIb metal salts appear to be true dual reagents. Application of these formulations to latent fingerprints on paper is as efficient as the two-step process beginning with ninhydrin and followed by treatment with metal salt. In the color mode, fingerprint detectability with the two ninhydrin-metal salt reagents (one with zinc chloride and the other with cadmium chloride) is comparable with that of ninhydrin itself, in spite of the difference in color. The sensitivity is significantly higher in the fluorescence mode. To view the latent impressions the exhibits are treated with ninhydrin-metal salt reagents and observed under white light illumination and under fluorescence conditions. Cooling to liquid nitrogen temperature enhances the fluorescence considerably. In the shorter wavelength domain, ninhydrin-metal salt reagents exhibit higher sensitivity than the recently reported dual reagent, genipin. The latter is advantageous, however, in the longer wavelength domain, on paper items with strong self-fluorescence, such as brown wrapping paper or paper printed with fluorescent ink. Upon reduction of the ninhydrin concentration 10-fold, ninhydrin-metal salt formulations become purely fluorogenic reagents; no color is noticed but the fluorescence is as intense as with concentrated solutions. Working at lower concentrations is an advantage from ecological and economical viewpoints.

Coumaroyl iridoids and a depside from cranberry (Vaccinium macrocarpon)

Cranberry (Vaccinium macrocarpon) juice has been used for urinary tract infections for approximately 50 years. Recent research suggests that this botanical blocks adherence of pathogenic E. coli to urinary tract cells, thus preventing infection. While current evidence indicates that proanthocyanidins are responsible for this activity, these compounds may not reach the urinary tract; thus further investigation is warranted. Fractionation of cranberry juice concentrate was guided by a recently published antiadherence assay, and the resulting fractions were phytochemically characterized. Two new coumaroyl iridoid glycosides, 10-p-trans- (1) and 10-p-cis-coumaroyl-1S-dihydromonotropein (2), and a depside, 2-O-(3,4-dihydroxybenzoyl)-2,4,6-trihydroxyphenylmethylacetate (3), were isolated, and although these compounds did not have antiadherent activity in isolation, they might constitute a new group of marker compounds for this active fraction of cranberry.

Microstructural and tensile properties of elastin-based polypeptides crosslinked with Genipin and pyrroloquinoline quinone

Elastin is an elastomeric, self-assembling extracellular matrix protein with potential for use in biomaterials applications. Here, we compare the microstructural and tensile properties of the elastin-based recombinant polypeptide (EP) EP20-244 crosslinked with either genipin (GP) or pyrroloquinoline quinone (PQQ). Recombinant EP-based sheets were produced via coacervation and subsequent crosslinking. The micron-scale topography of the GP-crosslinked sheets examined with atomic force microscopy revealed the presence of extensive mottling compared with that of the PQQ-crosslinked sheets, which were comparatively smoother. Confocal microscopy showed that the subsurface porosity in the GP-crosslinked sheets was much more open. GP-crosslinked EP-based sheets exhibited significantly greater tensile strength (P < or = 0.05). Mechanistically, GP appears to yield a higher crosslink density than PQQ, likely due to its capacity to form short-range and long-range crosslinks. In conclusion, GP is able to strongly modulate the microstructural and mechanical properties of elastin-based polypeptide biomaterials forming membranes with mechanical properties similar to native insoluble elastin.

Preparation and characterization of novel polymeric microcapsules for live cell encapsulation and therapy

This article describes the preparation and in vitro characterization of novel genipin cross-linked alginate-chitosan (GCAC) microcapsules that have potential for live cell therapy applications. This microcapsule system, consisting of an alginate core with a covalently cross-linked chitosan membrane, was formed via ionotropic gelation between calcium ions and alginate, followed by chitosan coating by polyelectrolyte complexation and covalent cross-linking of chitosan by naturally derived genipin. Results showed that, using this design concept and the three-step procedure, spherical GCAC microcapsules with improved membrane strength, suppressed capsular swelling, and suitable permeability can be prepared. The suitability of this novel membrane formulation for live cell encapsulation was evaluated, using bacterial Lactobacillus plantarum 80 (pCBH1) (LP80) and mammalian HepG2 as model cells. Results showed that capsular integrity and bacterial cell viability were sustained 6 mo postencapsulation, suggesting the feasibility of using this microcapsule formulation for live bacterial cell encapsulation. The metabolic activity of the encapsulated HepG2 was also investigated. Results suggested the potential capacity of this GCAC microcapsule in cell therapy and the control of cell signaling; however, further research is required.