Analysis and Calibration of Electron-Dispersive Spectroscope and Scanning Electron Microscope Parameters to Improve their Results

The Scanning electron microscope (SEM) and Electron-Dispersive Spectroscope (EDS) are two highly effective instruments in the field of nanoscience and nanotechnology. The quality of these instruments is determined by various factors, with high resolution being a crucial one. To determine the practically achievable resolution of the SEM, reference materials such as gold particles on carbon substrate are commonly utilized. On the other hand, high demanding, and usual materials such as brass, aluminum oxide or MEMs are of high importance to be considered in the way of improving material characterization. In this study five different samples were analyzed in four steps to see the effect of astigmatism and aperture misalignment, the mirror effect on the charged uncoated sample in backscattered electron (BSE) and secondary electron (SE) images, compositional and topographical analysis using both qualitative and quantitative methods and finally apply all the steps on a micro-electromechanical system (MEMS) device. This study illustrates the possibility of controlling the mirror effect by adjusting the input parameters even in the cases that the user needs to have low accelerating voltage for the experiment. Besides, the discussion addresses possible reasons for the absence of some peaks in EDS analysis for some specific elements

The effect of Amine modification on siRNA delivery of redox-responsive PEGylated amphiphilic micellar nanoparticles for triple negative breast cancer therapy

We developed a set of methoxypoly(ethyleneglycol)-co-poly(N3-ε-caprolactone) (mPEG-N3PCL)copolymers with different types of amine linkers and investigated thecontribution of the introduced amino linker to the gene delivery efficiency ofnanoparticles. The nanoparticles were crosslinked from the caprolactone regionswith a redox-responsive linker. Formulation variables including Redox-crosslinkingand N:P ratio were examined to obtain nanoparticles with optimal size andhighest siRNA entrapment efficacy (EE). The nanoparticles were characterized byDLS, and nanodrop UV-vis spectroscopy.Nanoparticle size, polydispersity index and siRNAentrapment efficacy were found to depend on the all the examined formulationvariables specially the N:P ratio. The formulation with N:P ratio of 5 with56.13 nm in size and 92.24% EE was chosen as the optimal formulation.Controllable size, loading efficiency and releasepattern by redox-responsivity make this class of novel carriers a promisingcandidate for tumour targeted gene delivery applications

Histopathological impact of Redox-responsive methacrylamide based micellar nanoparticles on Orthotopic Models of Triple Negative Breast Cancers

The therapeutic efficacy of anticancer nanocarriers ishighly dependent on their size, shape, targeting ability, and stimuli-responsiveness. Herein, we studied the in vivo therapeutic efficacy ofDoxorubicin (Dox) loaded redox responsive micellar-like nanoparticles (MNPs) based on linear 2-hydroxypropyl methacrylamide (HPMA) via histopathological evaluations. The therapeutic efficacy of DOX-loaded micellar-like Nanoparticles significantly improved while the side effects reduced as confirmed by histopathological examinations. H&E and tunnel staining of tumor tissues indicated the higher population of apoptotic tumor cells in both treatment groups containing DOX. These redox responsive crosslinked HPMA-based micellar-like nanoparticles with acceptable therapeutic efficacy and apoptosis induction in cancerous cells proved to be promising nanomedicine for breast cancer chemotherapy

Ultrasound-guided chemoradiotherapy of breast cancer using smart methotrexate-loaded perfluorohexane nanodroplets

Chemoradiotherapy with controlled-release nanocarriers such as sono-sensitive nanodroplets (NDs) can enhance the anticancer activity of chemotherapy medicines and reduces normal tissue side effects. In this study, folic acid-functionalized methotrexate-loaded perfluorohexane NDs with alginate shell (FA-MTX/PFH@alginate NDs) were synthesized, characterized, and their potential for ultrasound-guided chemoradiotherapy of breast cancer was investigated in vitro and in vivo. The cancer cell (4T1) viabilities and surviving fractions after NDs and ultrasound treatments were significantly decreased. However, this reduction was much more significant for ultrasound in combination with X-ray irradiation. The in vitro and in vivo results confirmed that MTX-loaded NDs are highly biocompatible and they have no significant hemolytic activity and organ toxicity. Furthermore, the in vivo results indicated that the FA-MTX/PFH@alginate NDs were accumulated selectively in the tumor region. In conclusion, FA-functionalized MTX/PFH@alginate NDs have a great theranostic performance for ultrasound-controlled drug delivery in combination with radiotherapy of breast cancer

Polymer Architecture Alters Tissue Distribution and Enhances Cytotoxicity Profiles in Orthotopic Models of Triple Negative Breast Cancers

The efficacy of nanomedicines is dependent on their access to target sites in the body, and this in turn is affected by their size, shape and transport properties in tissue. Although there have been many studies, the ability to design nanomaterials with optimal physicochemical properties for in vivo efficacy remains a significant challenge. In particular, it is difficult to quantify the detailed effects of cancer drug delivery systems in vivo as tumour volume reduction, a commonly reported marker of efficacy, does not always correlate with cytotoxicity in tumour tissue. Here, we studied the behaviour in vivo of two specific poly(2-hydroxypropyl methacrylamide) (pHPMA) pro-drugs, with the same chemical compositions of redox-responsive backbone components and pH-sensitive linkers to the anti-cancer drug doxorubicin but with varying architectures, in this case hyperbranched and star-shaped. Evaluation of the biodistribution of these polymers following systemic injection indicated differences in the circulation time and organ distribution of the two polymers, despite their very similar hydrodynamic radii (~ 10 and 15 nm) and underlying chemistry of backbone, side-chain and pro-drug linkers. In addition, both polymers showed improved tumour accumulation in orthotopic triple-negative breast cancers in mice, and decreased accumulation in healthy tissue, as compared to free doxorubicin. Importantly, there was a significant increase in tumour accumulation for the hyper-branched polymer compared to the star polymer, suggesting a possible role for solution conformations of these materials, rather than the chemistries, in mediating their performance. The results of haematoxylin and eosin assays, and TUNEL staining indicated a higher population of apoptotic cells in the tumours for both polymer pro-drug treatments, and in turn a lower population of apoptotic cells in the heart, liver and spleen, as compared to free doxorubicin. In particular, the hyperbranched polymer demonstrated significantly higher tumour deposition and apoptosis levels than its star shaped counterpart. Taken together, these data suggest that the penetration of both of these polymer pro-drugs was enhanced in tumour tissue relative to free doxorubicin, and that the combination of size, architecture, bioresponsive backbone and drug linker degradation yielded greater efficacy for the polymers as measured by biomarkers other than that of tumour volume

Chain-Extension in Hyperbranched Polymers Alters Tissue Distribution and Cytotoxicity Profiles in Orthotopic Models of Triple Negative Breast Cancers

The efficacy of nanomedicines is dependent on their access to target sites in the body, and this in turn is affected by their size, shape and transport properties in tissue. Although there have been many studies, the ability to design nanomaterials with optimal physicochemical properties for in vivo efficacy remains a significant challenge. In particular, it is difficult to quantify the detailed effects of cancer drug delivery systems in vivo as tumour volume reduction, a commonly reported marker of efficacy, does not always correlate with cytotoxicity in tumour tissue. Here, we studied the behaviour in vivo of two specific poly(2-hydroxypropyl methacrylamide) (pHPMA) pro-drugs, with the same chemical compositions of redox-responsive backbone components and pH-sensitive linkers to the anti-cancer drug doxorubicin but with varying architectures, in this case hyperbranched and star-shaped. Evaluation of the biodistribution of these polymers following systemic injection indicated differences in the circulation time and organ distribution of the two polymers, despite their very similar hydrodynamic radii (~ 10 and 15 nm) and underlying chemistry of backbone, side-chain and pro-drug linkers. In addition, both polymers showed improved tumour accumulation in orthotopic triple-negative breast cancers in mice, and decreased accumulation in healthy tissue, as compared to free doxorubicin. Importantly, there was a significant increase in tumour accumulation for the hyper-branched polymer compared to the star polymer, suggesting a possible role for solution conformations of these materials, rather than the chemistries, in mediating their performance. The results of haematoxylin and eosin assays, and TUNEL staining indicated a higher population of apoptotic cells in the tumours for both polymer pro-drug treatments, and in turn a lower population of apoptotic cells in the heart, liver and spleen, as compared to free doxorubicin. In particular, the hyperbranched polymer demonstrated significantly higher tumour deposition and apoptosis levels than its star shaped counterpart. Taken together, these data suggest that the penetration of both of these polymer pro-drugs was enhanced in tumour tissue relative to free doxorubicin, and that the combination of size, architecture, bioresponsive backbone and drug linker degradation yielded greater efficacy for the polymers as measured by biomarkers other than that of tumour volume

Free Drug and ROS-Responsive Nanoparticle Delivery of Synergistic Doxorubicin and Olaparib Combinations to Triple Negative Breast Cancer Models

Combinations of the topoisomerase II inhibitor doxorubicin and the poly (ADP-ribose) polymerase inhibitor olaparib offer potential drug-drug synergy for the treatment of triple negative breast cancers (TNBC). In this study we performed in vitro screening of combinations of these drugs, administered directly or encapsulated within polymer nanoparticles, in both 2D and in 3D spheroid models of breast cancer. A variety of assays were used to evaluate drug potency, and calculations of combination index (CI) values indicated that synergistic effects of drug combinations occurred in a molar-ratio dependent manner. It is suggested that the mechanisms of synergy were related to enhancement of DNA damage as shown by the level of double-strand DNA breaks, and mechanisms of antagonism associated with mitochondrial mediated cell survival, as indicated by reactive oxygen species (ROS) generation. Enhanced drug delivery and potency was observed with nanoparticle formulations, with a greater extent of doxorubicin localised to cell nuclei as evidenced by microscopy, and higher cytotoxicity at the same time points compared to free drugs. Together, the work presented identifies specific combinations of doxorubicin and olaparib which were most effective in a panel of TNBC cell lines, explores the mechanisms by which these combined agents might act, and shows that formulation of these drug combinations into polymeric nanoparticles at specific ratios conserves synergistic action and enhanced potency in vitro compared to the free drugs