5 research outputs found
Two-dimensional graphitic carbon nitride (g-C3N4) nanosheets and their derivatives for diagnosis and detection applications
The early diagnosis of certain fatal diseases is vital for preventing severe consequences and
contributes to a more effective treatment. Despite numerous conventional methods to realize this goal,
employing nanobiosensors is a novel approach that provides a fast and precise detection. Recently,
nanomaterials have been widely applied as biosensors with distinctive features. Graphite phase
carbon nitride (g-C3N4) is a two-dimensional (2D) carbon-based nanostructure that has received
attention in biosensing. Biocompatibility, biodegradability, semiconductivity, high photoluminescence
yield, low-cost synthesis, easy production process, antimicrobial activity, and high stability are
prominent properties that have rendered g-C3N4 a promising candidate to be used in electrochemical,
optical, and other kinds of biosensors. This review presents the g-C3N4 unique features, synthesis
methods, and g-C3N4-based nanomaterials. In addition, recent relevant studies on using g-C3N4 in
biosensors in regard to improving treatment pathways are reviewed
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A comprehensive review of synthesis, structure, properties, and functionalization of MoS2; emphasis on drug delivery, photothermal therapy, and tissue engineering applications
This review article is focused on the drug delivery platforms and cancer treatment systems recently developed based on molybdenum disulfide (MoS2) nanosheets. Two-dimensional MoS2 can be used as a therapeutic nanoparticle and tissue engineering scaffold for tumor healing. Structure, different synthesis methods, unique properties, and surface modification approaches of MoS2 as a newly emerging carrier for a wide range of drugs were comprehensively discussed. Numerous examples of drug delivery systems based on these carriers were introduced, and their key characteristics and highlights were compared in tables. Striking features in the two-dimensional nanostructure state like the high degree of anisotropy, mechanical strength, biocompatibility, large surface area, availability of surface modification methods for enhanced functionality, distinctive band gap structure, high absorbance in the near-infrared region, and remarkable magnetic attributes render MoS2 an ideal and attractive candidate to develop multifunctional platforms for combined chemotherapy and photothermal therapy as well as biosensing and bioimaging applications. These properties have piqued the interest of many researchers and led them to study the versatile biomedical applications of these materials, particularly drug delivery and photothermal therapy. Finally, the opportunities, remaining challenges, and future prospects ahead in this area were mapped out
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Properties and application of carbon quantum dots (CQDs) in biosensors for disease detection: A comprehensive review
In the areas of bioimaging and detection, biosensors have attracted extensive attention recently. Specifically, biosensors based on nanostructures provide a more sensitive detection due to their prominent properties. Different biosensors have used quantum dots (QDs) due to their unique properties, like high quantum yield (QY) and photoluminescence. In addition to possessing the advantages of common QDs, carbon quantum dots (CQDs) have a higher solubility, lower toxicity, and easier synthesis, making them highly useful and a promising candidate for biomedical applications. The CQD is a zero-dimensional nanostructure with a size of less than 10 nm in every dimension. The unparallel features of CQDs, including good biocompatibility and unique optical properties, like high photoluminescence (PL) and Quantum yield (QY), make them attractive candidates for biosensor and bioimaging applications. This review examines the recent advances in biosensors based on CQDs and presents the properties, challenges, and future perspectives to pave the way for further studies in the future
Global age-sex-specific mortality, life expectancy, and population estimates in 204 countries and territories and 811 subnational locations, 1950–2021, and the impact of the COVID-19 pandemic: a comprehensive demographic analysis for the Global Burden of Disease Study 2021
BackgroundEstimates of demographic metrics are crucial to assess levels and trends of population health outcomes. The profound impact of the COVID-19 pandemic on populations worldwide has underscored the need for timely estimates to understand this unprecedented event within the context of long-term population health trends. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 provides new demographic estimates for 204 countries and territories and 811 additional subnational locations from 1950 to 2021, with a particular emphasis on changes in mortality and life expectancy that occurred during the 2020–21 COVID-19 pandemic period.Methods22 223 data sources from vital registration, sample registration, surveys, censuses, and other sources were used to estimate mortality, with a subset of these sources used exclusively to estimate excess mortality due to the COVID-19 pandemic. 2026 data sources were used for population estimation. Additional sources were used to estimate migration; the effects of the HIV epidemic; and demographic discontinuities due to conflicts, famines, natural disasters, and pandemics, which are used as inputs for estimating mortality and population. Spatiotemporal Gaussian process regression (ST-GPR) was used to generate under-5 mortality rates, which synthesised 30 763 location-years of vital registration and sample registration data, 1365 surveys and censuses, and 80 other sources. ST-GPR was also used to estimate adult mortality (between ages 15 and 59 years) based on information from 31 642 location-years of vital registration and sample registration data, 355 surveys and censuses, and 24 other sources. Estimates of child and adult mortality rates were then used to generate life tables with a relational model life table system. For countries with large HIV epidemics, life tables were adjusted using independent estimates of HIV-specific mortality generated via an epidemiological analysis of HIV prevalence surveys, antenatal clinic serosurveillance, and other data sources. Excess mortality due to the COVID-19 pandemic in 2020 and 2021 was determined by subtracting observed all-cause mortality (adjusted for late registration and mortality anomalies) from the mortality expected in the absence of the pandemic. Expected mortality was calculated based on historical trends using an ensemble of models. In location-years where all-cause mortality data were unavailable, we estimated excess mortality rates using a regression model with covariates pertaining to the pandemic. Population size was computed using a Bayesian hierarchical cohort component model. Life expectancy was calculated using age-specific mortality rates and standard demographic methods. Uncertainty intervals (UIs) were calculated for every metric using the 25th and 975th ordered values from a 1000-draw posterior distribution.FindingsGlobal all-cause mortality followed two distinct patterns over the study period: age-standardised mortality rates declined between 1950 and 2019 (a 62·8% [95% UI 60·5–65·1] decline), and increased during the COVID-19 pandemic period (2020–21; 5·1% [0·9–9·6] increase). In contrast with the overall reverse in mortality trends during the pandemic period, child mortality continued to decline, with 4·66 million (3·98–5·50) global deaths in children younger than 5 years in 2021 compared with 5·21 million (4·50–6·01) in 2019. An estimated 131 million (126–137) people died globally from all causes in 2020 and 2021 combined, of which 15·9 million (14·7–17·2) were due to the COVID-19 pandemic (measured by excess mortality, which includes deaths directly due to SARS-CoV-2 infection and those indirectly due to other social, economic, or behavioural changes associated with the pandemic). Excess mortality rates exceeded 150 deaths per 100 000 population during at least one year of the pandemic in 80 countries and territories, whereas 20 nations had a negative excess mortality rate in 2020 or 2021, indicating that all-cause mortality in these countries was lower during the pandemic than expected based on historical trends. Between 1950 and 2021, global life expectancy at birth increased by 22·7 years (20·8–24·8), from 49·0 years (46·7–51·3) to 71·7 years (70·9–72·5). Global life expectancy at birth declined by 1·6 years (1·0–2·2) between 2019 and 2021, reversing historical trends. An increase in life expectancy was only observed in 32 (15·7%) of 204 countries and territories between 2019 and 2021. The global population reached 7·89 billion (7·67–8·13) people in 2021, by which time 56 of 204 countries and territories had peaked and subsequently populations have declined. The largest proportion of population growth between 2020 and 2021 was in sub-Saharan Africa (39·5% [28·4–52·7]) and south Asia (26·3% [9·0–44·7]). From 2000 to 2021, the ratio of the population aged 65 years and older to the population aged younger than 15 years increased in 188 (92·2%) of 204 nations.InterpretationGlobal adult mortality rates markedly increased during the COVID-19 pandemic in 2020 and 2021, reversing past decreasing trends, while child mortality rates continued to decline, albeit more slowly than in earlier years. Although COVID-19 had a substantial impact on many demographic indicators during the first 2 years of the pandemic, overall global health progress over the 72 years evaluated has been profound, with considerable improvements in mortality and life expectancy. Additionally, we observed a deceleration of global population growth since 2017, despite steady or increasing growth in lower-income countries, combined with a continued global shift of population age structures towards older ages. These demographic changes will likely present future challenges to health systems, economies, and societies. The comprehensive demographic estimates reported here will enable researchers, policy makers, health practitioners, and other key stakeholders to better understand and address the profound changes that have occurred in the global health landscape following the first 2 years of the COVID-19 pandemic, and longer-term trends beyond the pandemic