Constraints on the near-Earth asteroid obliquity distribution from the Yarkovsky effect

Aims. From lightcurve and radar data we know the spin axis of only 43 near-Earth asteroids. In this paper we attempt to constrain the spin axis obliquity distribution of near-Earth asteroids by leveraging the Yarkovsky effect and its dependence on an asteroid’s obliquity. Methods. By modeling the physical parameters driving the Yarkovsky effect, we solve an inverse problem where we test different simple parametric obliquity distributions. Each distribution results in a predicted Yarkovsky effect distribution that we compare with a X2 test to a dataset of 125 Yarkovsky estimates. Results. We find different obliquity distributions that are statistically satisfactory. In particular, among the considered models, the best-fit solution is a quadratic function, which only depends on two parameters, favors extreme obliquities, consistent with the expected outcomes from the YORP effect, has a 2:1 ratio between retrograde and direct rotators, which is in agreement with theoretical predictions, and is statistically consistent with the distribution of known spin axes of near-Earth asteroids

Milk exosomes: Nature\u27s abundant nanoplatform for theranostic applications

Exosomes are a unique subpopulation of naturally occurring extracellular vesicles which are smaller intracellular membrane nanoparticle vesicles. Exosomes have proven to be excellent nanocarriers for carrying lipids, proteins, mRNAs, non-coding RNAs, and DNAs, and disseminating long-distance intercellular communications in various biological processes. Among various cell-line or biological fluid derived exosomes, milk exosomes are abundant in nature and exhibit many nanocarrier characteristics favorable for theranostic applications. To be an effective delivery carrier for their clinical translation, exosomes must inbuilt loading, release, targeting, and imaging/tracking characteristics. Considering the unmet gaps of milk exosomes in theranostic technology it is essential to focus the current review on drug delivery and imaging applications. This review delineates the efficiency of exosomes to load therapeutic or imaging agents and their successful delivery approaches. It is emphasized on possible modifications of exosomes towards increasing the stability and delivery of agents. This article also summarizes the specific applications and the process of developing milk exosomes as a future pharmaceutical drug delivery vehicle

A Natural Near-Infrared Fluorescent Probe for Cancer Cell Imaging

Background: Rio Grande Valley (RGV) suffers from a high prevalence of certain cancers and lack the resources for accurate early diagnosis. Near-infrared (NIR) fluorescence-based imaging is a noteworthy and safer strategy for cancer detection compared to radiological imaging. There are several NIR dyes including indocyanine green (ICG) and its analogues that allow high-resolution and deep tissue imaging. However, these dyes possess some drawbacks, namely photo instability, toxicity, poor water solubility, and short half-lives. Chlorophyll (Chl) is a natural dietary and biocompatible NIR fluorescent substance which has the potential to serve as a cancer NIR imaging candidate. Hence, we aim to extract Chl from dietary leaves for cancer cell imaging. Methods: 12 different dietary leaves were imaged using the IVIS imaging system at 600/710 nm to assess the fluorescence distribution of chlorophyll. Next, Chl dye was extracted using ethanol from the 6 most fluorescent leaves and visualized for fluorescence. Size distribution, surface charge, and the concentration of these extracts were measured by a DLS system. Chl internalization in AsPC-1 (pancreatic) and SK-HEP-1 (liver) cancer cell lines was determined by EVOS imaging system after treated with highest fluorescent extract at different concentrations. Results: IVIS imaging data revealed that Chl was most fluorescent in bay leaf extract (4.98x1010 MFI). Physicochemical characterization of bay leaf extracted Chl indicated the particle size of 62.7 nm, zeta potential of -24.76 mV, and concentration at 1.11x1012 particles/mL. Cellular internalization data showed a dose dependent increase in bay leaf extracted Chl fluorescence in both cancer cell lines. Conclusions: This data suggests that dietary Chl is a potent biocompatible alternative for cancer cells NIR fluorescent imaging

A Natural Near-Infrared Fluorescent Probe for Cancer Cell Imaging

Introduction: Near-Infrared (NIR) fluorescence-based imaging is a noteworthy and safer strategy for cancer cells/tissues imaging compared to radiological imaging. NIR fluorescence offers deep tissue penetration and have minimal obstruction by autofluorescence and photon scattering [1]. There are several NIR dyes including indocyanine green (ICG) [2] and IR-1061 [3] that allow high-resolution tissue imaging. However, these dyes possess some low-quality characteristics which limit their use, namely photo instability, toxicity, poor water solubility, and short half-lives [4]. Therefore, more efficient and effective alternatives are urgently required to provide the desired clinical outcomes. Chlorophyll (Chl) is a natural dietary NIR fluorescence emitting substance which has the potential to serve as a lead NIR imaging candidate for cancer administration [5]. Objective: Developing a biocompatible NIR imaging dye from natural resources that can facilitate cancer cells/tissues imaging for improved detection. Chlorophyll is a natural NIR fluorescent alternative that is widely present in plants and green vegetables. Hence, we aim to extract Chl from dietary herbs and vegetables for cancer imaging. Methods: We selected 12 different leaves such as basil, bay leaf, collard, dill, kale, lettuce, mint, oregano, rosemary, sage, spinach, and thyme to assess the fluorescence distribution of chlorophyll. Each leaf was imaged in triplicates using the IVIS In Vivo Imaging System to detect Chl with excitation and emission wavelengths at 600/710 nm. Based on fluorescent intensity levels, next, we selected the 6 most fluorescent leaves (Bay leaf, collard, lettuce, mint, oregano, and spinach) and extracted the Chl dye using ethanol. The extracts were again visualized with IVIS system for Chl detection. Further, a Dynamic Light Scattering (DLS) system was used to measure size distribution, surface charge and the concentration of these Chl extracts. In order to determine the Chl internalization in cancer cells, AsPC-1 (pancreatic) and SK-HEP-1 (liver), two cell lines were treated with bay leaf (highest fluorescence) extracted Chl at different concentrations (10, 20, 30, 40 and 50 µg) for an hour and imaged under red channel using an EVOS Imaging System. Results: Whole leaf IVIS imaging revealed that spinach had the maximum Chl fluorescence of ~ 1.92x1012 and the lowest was in thyme ~ 8.60x1010. On the other hand, extracted Chl was most detectable in bay leaf extract (~ 4.98x1010). Additionally, physicochemical characterization of extracted Chl from these leaves suggested the particle size range of ~ 50 to 230 nm (Bay leaf 62.7 nm), zeta potential of ~ -20 to -25 (Bay leaf -24.76) and the obtained concentrations were, 1.11x1012 for bay leaf (Highest) and 5.01x109 for lettuce (Lowest). Moreover, cellular internalization data obtained using a fluorescent microscopy indicated a dose dependent increase in the bay leaf extracted Chl fluorescence in both cell lines. However, the fluorescence level was more prominent in the SK-HEP-1 cells compared to AsPC-1. Discussion: NIR fluorescent dyes play a significant role when it comes to the early stage cancer detection. Chlorophyll has NIR fluorescent excitation ~ 604 nm and emission ~ 700 nm which offers the capability of high-resolution imaging with deep tissue penetration, making it ideal for cancer imaging. Extraction process of Chl from dietary leaves is highly scalable and reproducible, herein, we have screened different leaves for Chl fluorescence, and it was evident that bay leaf exhibited the highest yield and Chl fluorescence. Conclusions: Taken together, our data suggested that Chl extracted from dietary resources, is a potent biocompatible alternative for NIR fluorescence which can be applied to cancer cells and tissues/tumors for enhanced detection resolution

Developing A Chlorophyll-Based Near-Infrared Fluorescent Probe for Cancer Cell Imaging

Introduction: Near-Infrared (NIR) fluorescence-based imaging is a noteworthy and safer strategy for cancer cells/tissues imaging compared to radiological imaging. NIR fluorescence offers deep tissue penetration and have minimal obstruction by autofluorescence and photon scattering [1]. There are several NIR dyes including indocyanine green (ICG) [2] and IR-1061 [3] that allow high-resolution tissue imaging. However, these dyes possess some low-quality characteristics which limit their use, namely photo instability, toxicity, poor water solubility, and short half-lives [4]. Therefore, more efficient and effective alternatives are urgently required to provide the desired clinical outcomes. Chlorophyll (Chl) is a natural dietary NIR fluorescence emitting substance which has the potential to serve as a lead NIR imaging candidate for cancer administration [5]. Objective: Developing a biocompatible NIR imaging dye from natural resources that can facilitate cancer cells/tissues imaging for improved detection. Chlorophyll is a natural NIR fluorescent alternative that is widely present in plants and green vegetables. Hence, we aim to extract Chl from dietary herbs and vegetables for cancer imaging. Methods: We selected 12 different leaves such as basil, bay leaf, collard, dill, kale, lettuce, mint, oregano, rosemary, sage, spinach, and thyme to assess the fluorescence distribution of chlorophyll. Each leaf was imaged in triplicates using the IVIS In Vivo Imaging System to detect Chl with excitation and emission wavelengths at 600/710 nm. Based on fluorescent intensity levels, next, we selected the 6 most fluorescent leaves (Bay leaf, collard, lettuce, mint, oregano, and spinach) and extracted the Chl dye using ethanol. The extracts were again visualized with IVIS system for Chl detection. Further, a Dynamic Light Scattering (DLS) system was used to measure size distribution, surface charge and the concentration of these Chl extracts. In order to determine the Chl internalization in cancer cells, AsPC-1 (pancreatic) and SK-HEP-1 (liver), two cell lines were treated with bay leaf (highest fluorescence) extracted Chl at different concentrations (10, 20, 30, 40 and 50 µg) for an hour and imaged under red channel using an EVOS Imaging System. Results: Whole leaf IVIS imaging revealed that spinach had the maximum Chl fluorescence of ~ 1.92x1012 and the lowest was in thyme ~ 8.60x1010. On the other hand, extracted Chl was most detectable in bay leaf extract (~ 4.98x1010). Additionally, physicochemical characterization of extracted Chl from these leaves suggested the particle size range of ~ 50 to 230 nm (Bay leaf 62.7 nm), zeta potential of ~ -20 to -25 (Bay leaf -24.76) and the obtained concentrations were, 1.11x1012 for bay leaf (Highest) and 5.01x109 for lettuce (Lowest). Moreover, cellular internalization data obtained using a fluorescent microscopy indicated a dose dependent increase in the bay leaf extracted Chl fluorescence in both cell lines. However, the fluorescence level was more prominent in the SK-HEP-1 cells compared to AsPC-1. Discussion: NIR fluorescent dyes play a significant role when it comes to the early stage cancer detection. Chlorophyll has NIR fluorescent excitation ~ 604 nm and emission ~ 700 nm which offers the capability of high-resolution imaging with deep tissue penetration, making it ideal for cancer imaging. Extraction process of Chl from dietary leaves is highly scalable and reproducible, herein, we have screened different leaves for Chl fluorescence, and it was evident that bay leaf exhibited the highest yield and Chl fluorescence. Conclusions: Taken together, our data suggested that Chl extracted from dietary resources, is a potent biocompatible alternative for NIR fluorescence which can be applied to cancer cells and tissues/tumors for enhanced detection resolution

Bay Leaf Extract‐Based Near‐Infrared Fluorescent Probe for Tissue and Cellular Imaging

The development of fluorescence dyes for near‐infrared (NIR) fluorescence imaging has been a significant interest for deep tissue imaging. Among many imaging fluoroprobes, indocyanine green (ICG) and its analogues have been used in oncology and other medical applications. However, these imaging agents still experience poor imaging capabilities due to low tumor targetability, photostability, and sensitivity in the biological milieu. Thus, developing a biocompatible NIR imaging dye from natural resources holds the potential of facilitating cancer cell/tissue imaging. Chlorophyll (Chl) has been demonstrated to be a potential candidate for imaging purposes due to its natural NIR absorption qualities and its wide availability in plants and green vegetables. Therefore, it was our aim to assess the fluorescence characteristics of twelve dietary leaves as well as the fluorescence of their Chl extractions. Bay leaf extract, a high‐fluorescence agent that showed the highest levels of fluorescence, was further evaluated for its tissue contrast and cellular imaging properties. Overall, this study confirms bay‐leaf‐associated dye as a NIR fluorescence imaging agent that may have important implications for cellular imaging and image‐guided cancer surgery

Photocatalytic degradation of fluoroquinolone antibiotics in solution by Au@ZnO-rGO-gC3N4 composites

The photocatalytic degradation of two quinolone-type antibiotics (ciprofloxacin and levofloxacin) in aqueous solution was studied, using catalysts based on ZnO nanoparticles, which were synthesized by a thermal procedure. The efficiency of ZnO was subsequently optimized by incorporating different co-catalysts of gC3N4, reduced graphene oxide, and nanoparticles of gold. The catalysts were fully characterized by electron microscopy (TEM and SEM), XPS, XRD, Raman, and BET surface area. The most efficient catalyst was 10%Au@ZnONPs-3%rGO-3%gC3N4, obtaining degradations of both pollutants above 96%. This catalyst has the largest specific area, and its activity was related to a synergistic effect, involving factors such as the surface of the material and the ability to absorb radiation in the visible region, mainly produced by the incorporation of rGO and gC3N4 in the semiconductor. The use of different scavengers during the catalytic process, was used to establish the possible photodegradation mechanism of both antibiotics

A Novel Exo-Glow Nano-system for Cellular Imaging

Background: Indocyanine green (ICG) based Near-Infrared (NIR) fluorescent imaging is an attractive and safer technique used for number of clinical applications. However, ICG tend to have poor photostability, short half-life, non-specific proteins binding, and concentration-dependent aggregation. Therefore, there is an unmet clinical need to develop newer modalities to package and deliver ICG. Bovine milk exosomes are natural, biocompatible, safe, and feasible nanocarriers that facilitate the delivery of micro and macro molecules. Herein, we developed a novel exosomes based ICG nano imaging system that offers improved solubility and photostability of ICG. Methods: Following acetic acid based extracellular vesicles (EV) extraction method, we extracted the bovine milk exosomes from a variety of pasteurized fat-free milks. The EVs were screened for their physicochemical properties such as particle size and concentration, and zeta potential. Stability of these exosomes was also determined under different conditions including storage temperatures, pH, and salt concentrations. Next, ICG dye was loaded into these exosomes (Exo-Glow) via sonication method and further assessed for its fluorescence intensity and photostability using an IVIS imaging system. Results: Initial screening suggested that size of the selected bovine milk exosomes was from 100 - 135 nm with an average particle concentration of 5.8x102 particles/mL. Exo-Glow (ICG loaded exosomes) further showed higher fluorescence intensity of ~ 2x1010 MFI compared to free ICG (~ 8.1x109 MFI). Conclusions: These results showed that Exo-Glow has the potential to improve solubility, photostability, and biocompatibility of ICG and may serve as a safer NIR imaging tool for cells/tissues