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At least 289 records · Page 16Linked to original sources
PubMed2026

Bioengineered zinc oxide nanoparticles derived from Teucrium polium as a multifunctional platform for anticancer activity, hemocompatibility, larval toxicity and photocatalytic remediation.

In this study, we evaluate the physicochemical properties and the antioxidant, antimicrobial, anticancer, photocatalytic, and larvicidal activities of T. polium-mediated ZnO NPs. The synthesized ZnO NPs were characterized by UV-visible spectroscopy (absorption at 392 nm), FTIR, TEM, and XRD, confirming their successful synthesis. The antioxidant activity of ZnO NPs was evaluated using various assays: DPPH scavenging at 54% (100 µg/mL), ABTS scavenging at 63.3% (100 µg/mL), FRAP scavenging at 61.2% (100 µg/mL), and hydrogen peroxide scavenging at 65% (100 µg/mL), demonstrating concentration-dependent activity. The antibacterial properties were tested against E. coli, P. aeruginosa, K. pneumoniae, and S. aureus, with the largest inhibition zone observed for P. aeruginosa (28.3 mm at 100 µg/mL). Cytotoxicity on MCF-7 cells showed a dose-dependent decrease in cell viability, with values of 75.6%, 44%, 20%, and 8% for concentrations of 25, 50, 75, and 100 µg/mL, respectively. ROS generation and apoptosis were also observed at higher concentrations. The photocatalytic degradation of Methyl Orange was evaluated under UV irradiation, yielding 85% degradation efficiency at pH 3 with a ZnO NP concentration of 50 mg/L. The larvicidal toxicity against Aedes aegypti was significant, with LC50 values of 76.63 µg/mL for III instar and 82.74 µg/mL for IV instar larvae. The results suggest that T. polium-mediated ZnO NPs possess significant potential for therapeutic applications, including antioxidant, antimicrobial, anticancer, photocatalytic, and larvicidal activities, making them a promising candidate for biomedical and environmental applications.

Zinc Oxide↗
PubMed2003

Bioengineered 'golden' indica rice cultivars with beta-carotene metabolism in the endosperm with hygromycin and mannose selection systems.

Vitamin-A deficiency (VAD) is a major malnutrition problem in South Asia, where indica rice is the staple food. Indica-type rice varieties feed more than 2 billion people. Hence, we introduced a combination of transgenes using the biolistic system of transformation enabling biosynthesis of provitamin A in the endosperm of several indica rice cultivars adapted to diverse ecosystems of different countries. The rice seed-specific glutelin promoter (Gt-1 P) was used to drive the expression of phytoene synthase (psy), while lycopene beta-cyclase (lcy) and phytoene desaturase (crtI), fused to the transit peptide sequence of the pea-Rubisco small subunit, were driven by the constitutive cauliflower mosaic virus promoter (CaMV35S P). Transgenic plants were recovered through selection with either CaMV35S P driven hph (hygromycin phosphotransferase) gene or cestrum yellow leaf curling virus promoter (CMP) driven pmi (phophomannose isomerase) gene. Molecular and biochemical analyses demonstrated stable integration and expression of the transgenes. The yellow colour of the polished rice grain evidenced the carotenoid accumulation in the endosperm. The colour intensity correlated with the estimated carotenoid content by spectrophotometric and HPLC analysis. Carotenoid level in cooked polished seeds was comparable (with minor loss of xanthophylls) to that in non-cooked seeds of the same transgenic line. The variable segregation pattern in T1 selfing generation indicated single to multiple loci insertion of the transgenes in the genome. This is the first report of using nonantibiotic pmi driven by a novel promoter in generating transgenic indica rice for possible future use in human nutrition.

Journal Article↗
PubMed2002

Wounding of bioengineered skin: cellular and molecular aspects after injury.

Skin substitutes are increasingly being used in the treatment of difficult to heal wounds but their mechanisms of action are largely unknown. In this study, using histology, immunostaining, flow cytometry, enzyme-linked immunosorbent assay, and reverse transcription polymerase chain reaction, we determined the response to injury of a human bilayered skin substitute. Meshing or scalpel fenestration of the construct was found to stimulate keratinocyte migration and to decrease proliferation. By 24 h, flow cytometry of the keratinocyte component showed that meshing was associated with a 33% decrease in the number of cells in S phase (p < 0.01). An approximately 2-fold decrease in staining for Ki67, a proliferation marker, was observed with meshing of human bilayered skin substitute. The process of reepithelialization was apparent by 12 h, however, the wounded human bilayered skin substitute was healed by day 3, and a stratum corneum and fully stratified epithelium were re-established by day 4. Reverse transcription polymerase chain reaction analysis and enzyme-linked immunosorbent assays showed that the expression of acute proinflammatory cytokines (interleukins 1alpha, 6, and 8, tumor necrosis factor alpha) peaked by 12-24 h postinjury. The levels of mRNA of certain growth factors (transforming growth factor beta1, vascular endothelial growth factor, insulin-like growth factor 2) but not others (platelet-derived growth factors A and B, keratinocyte growth factor, fibroblast growth factors 1 and 7, transforming growth factor beta3) increased by 12 h and peaked by 1-3 d after injury, returning to normal by day 6. Immunostaining for tumor necrosis factor alpha and transforming growth factor beta1 paralleled these findings by reverse transcription polymerase chain reaction. We conclude that human bilayered skin substitute, as a prototypic bilayered skin substitute, is a truly dynamic living tissue, capable of responding to physical injury in a staged and specific pattern of cell migration, reepithelialization, and cytokine expression.

Cytokines↗
PubMedDate not supplied

Direct comparison of skin physiology in children and adults with bioengineering methods.

The aim of the study was to investigate whether the physiologic skin parameters of transepidermal water loss (TEWL), stratum corneum hydration (capacitance and conductance), dynamic stratum corneum hydration parameters (hygroscopicity and water-holding capacity), skin color (a* and L* axes; chromameter), cutaneous blood perfusion [laser Doppler flowmetry (LDF)], and pH value differ between a sample of 44 children [C] (average age 3.5 years) and a directly comparable sample of 44 adults (their parents) [P] (average age 34.6 years). The results can be described as follows: TEWL C: 6.2 g/m2/h, P: 5.4 g/m2/h; stratum corneum hydration, capacitance C: 75.4 AU, P: 76.1 AU; conductance C: 27.1 microS, P: 19.2 microS; hygroscopicity C: 129.0 AU, P: 132.7 AU; water-holding capacity: C: 127.7 AU, P: 127.6 AU; redness (a*) C: 7.31, P: 8.21; lightness (L*) C: 67.63, P: 66.36; LDF (%) C: 24.6, P: 18.7; pH value C: 4.91, P: 5.07. In comparison to the skin of the adult sample we investigated (the parents of the 44 children), the skin of the small child can be characterized in the following way: it has a significantly lower hygroscopicity, a lighter (higher L* values) and less red color (lower a* values), and an increased cutaneous blood perfusion (LDF).

Adult↗
PubMed2004

A bubble-driven microfluidic transport element for bioengineering.

Microfluidics typically uses channels to transport small objects by actuation forces such as an applied pressure difference or thermocapillarity. We propose that acoustic streaming is an alternative means of directional transport at small scales. Microbubbles on a substrate establish well controlled fluid motion on very small scales; combinations ("doublets") of bubbles and microparticles break the symmetry of the motion and constitute flow transport elements. We demonstrate the principle of doublet streaming and describe the ensuing transport. Devices based on doublet flow elements work without microchannels and are thus potentially cheap and highly parallelizable.

Acoustics↗