In this work, we have successfully synthesized a bimetallic (Zinc and Cobalt) Zeolitic Imidazolate Framework (Zn50Co50-ZIF), a class in a wider microporous Metal-Organic Framework (MOF) family. The synthesized nanostructures maintain both water stability like ZIF-8 (solely Zn containing) and charge transfer electronic band in the visible optical spectrum as ZIF-67 (solely Co containing). Crystal structure from XRD, high resolution transmission electron microscopy (HRTEM) followed by elemental mapping (EDAX) confirm structural stability and omnipresence of the metal atoms (Zn and Co) across the nanomaterial with equal proportion. Existence of charge transfer state consistent with ZIF67 and intact ultrafast excited state dynamics of the imidazolate moiety in both ZIF-8 and ZIF-67, is evidenced from steady state and time resolved optical spectroscopy. The thermal and aqueous stabilities of Zn50Co50-ZIF are found to be better than ZIF-67 but comparable to ZIF-8 as evidenced by solubility, scanning electron microscopy (SEM) and XRD studies of the material in water. We have evaluated the photoinduced ROS generation by the mixed ZIF employing dichloro-dihydro-fluorescein diacetate (DCFH-DA) assay. We have also explored the potentiality of the synthesized material for the alternate remediation of methicillin resistant Staphylococcus aureus (MRSA) infection through the photoinduced reactive oxygen species (ROS) generation and methylene blue (MB) degradation kinetics.
To
realize a customizable biogenic delivery platform, herein we
propose combining cell-derived extracellular vesicles (EVs) derived
from breast cancer cell line MCF-7 with synthetic cationic liposomes
using a fusogenic agent, polyethylene glycol (PEG). We performed a
fluorescence resonance energy transfer (FRET)-based lipid-mixing assay
with varying PEG 1000 concentrations (0%, 15%, and 30%) correlated
with flow cytometry-based analysis and supported by dimensional analysis
by dynamic light scattering (DLS), transmission electron microscopy
(TEM), and atomic force microscopy (AFM) to validate our fusion strategy.
Our data revealed that these hybrid vesicles at a particular concentration
of PEG (∼15%) improved the cellular delivery efficiency of
a model siRNA molecule to the EV parental breast cancer cells, MCF-7,
by factors of 2 and 4 compared to the loaded liposome and EV precursors,
respectively. The critical rigidity/pliability balance of the hybrid
systems fused by PEG seems to be playing a pivotal role in improving
their delivery capability. This approach can provide clinically viable
delivery solutions using EVs.
The properties of nanomaterials generated by external stimuli are considered an innovative and promising replacement for the annihilation of bacterial infectious diseases.
Bacterial
infections instigated by antibiotic-resistant bacteria
are considered perilous health threats in today’s world due
to their fast-increasing nature and the fewer availability of new
treatment strategies. The properties of nanomaterials triggered by
external stimuli are considered an encouraging technique for the remediation
of antibacterial infectious diseases by producing photoinduced reactive
oxygen species (ROS). Light-mediated treatment using zinc oxide (ZnO)-based
nanohybrids leads the field with high interest in terms of sensitization
of antibiotics and their targeted delivery. Moreover, the dual sensitization
in a hybrid system could produce more efficacy as this phenomenon
has been implemented in dye sensitized solar cells and photocatalysis.
However, most of those hybrids are complicated and non-biocompatible.
The present study highlights a tri-hybrid by encapsulating tetracycline
(TC) in Au nanoparticle-decorated ZnO nanoparticles. The composition
and morphology of the samples were characterized by electron microscopy,
ultrafast optical spectroscopy, and density functional theory-based
techniques. The dual sensitization in the tri-hybrids leads to enhanced
antimicrobial activity against Gram-positive Staphylococcus
hominis bacteria due to immense ROS under white light
irradiation. The Förster resonance energy transfer from TC
to Au and the excited-state photo-electron transfer process in the
Au_ZnO-TC tri-hybrid system trigger a huge charge separation, which
enhances production of ROS. Due to such a huge ROS production capability,
the tri-hybrid shows a significant antibacterial action. Moreover,
the Au nanoparticle-decorated ZnO is capable of destroying excess
antibiotics, which potentially reduces the chance of development of
antibiotic resistance. Overall, the study demonstrates a promising
aspect that could be beneficial for manifold biological applications.
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