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To prevent interhuman transmission of viruses, new mask types─claiming improved filtration─require careful performance characterization. Here, a microfluidic spray device that can effectively simulate droplets emitted during coughing or sneezing was developed to spray droplets containing gold nanoparticles (AuNPs) that mimic SARS-CoV-2 to overcome the shortcomings associated with using biosamples. The light scattered by the AuNPs passing through the mask is successfully analyzed by using an automated scattering light mapping system within a duration of 2 min, thereby enabling high-throughput analysis of the filtering efficiency of various types of commercial masks. The differences in efficiency in terms of same mask type from different manufacturers, double masking, and prolonged usage, which are challenging to analyze with conventional testing systems, can also be assessed. AuNP-mediated mask performance evaluation enables the rapid determination of mask efficiency according to particle size and can contribute to the rapid response to counter new emerging infectious biohazards.

Hydrogen as a clean fuel is receiving attention because it generates only water and a small amount of nitrogen oxide upon combustion. Biohydrogen production using microalgae is considered to be a highly promising carbon-neutral technology because it can secure renewable energy while efficiently reducing CO

In this study, the effects of microalgae-based biomineralization in a semi-continuous process (M-BSP) on biomass productivity and CO

The microalgae-based bioconversion process is a promising carbon utilization technology because it can upgrade CO

Surface-enhanced Raman scattering (SERS) induced from nanostructured noble metals has a great potential for molecular detection and analysis. However, it has been a challenge to fabricate a reliabl...

The culture method using sodium acetate and glucose, widely used as organic carbon sources in the mixotrophy of Haematococcus pluvialis, was compared with its autotrophy. In the 12-day culture, mixotrophy using sodium acetate and glucose increased by 40.4% and 77.1%, respectively, compared to autotrophy, but the mechanisms for the increasing biomass were different. The analysis of the mechanism was divided into autotrophic and heterotrophic metabolism. The mixotrophy with glucose increased the biomass by directly supplying the substrate and ATP to the TCA cycle while inhibiting photosynthesis. Gene expressions related to glycolysis and carbon fixation pathway were confirmed in autotrophy and mixotrophy with glucose and acetate. The metabolism predicted in the mixotrophy with acetate and glucose was proposed via autotrophic and heterotrophic metabolism analysis. The mechanism of Haematococcus pluvialis under mixotrophic conditions with high CO

Wastewater generated by the food industry is rich in nitrogen and phosphorus with possible presence of heavy metals. Physical and chemical methods of treatment, although effective, are expensive and may cause secondary environmental pollution damaging aquatic and human life. Traditional biological methods are eco-friendly and cost-effective but involve standalone microorganisms that pose risk of contamination and are not as effective. This review discusses the application of novel microalgal-bacterial consortium as a solution for the resource recovery and treatment of dairy, starch and aquaculture wastewater. Use of biofilm reactors containing anaerobic and aerobic sludge has shown 80-90% and 90% COD and nutrient removal efficiency in treatment of dairy and starch processing wastewater, respectively. The treatment of aquaculture processing wastewater can be challenging due to high sality and requires salt-tolerant bacteria-microalgae consortium. In this regard, the identification of dominant microalgae and bacteria using 16S rRNA and 18S rRNA genes is recommended.

Economically feasible photosynthetic cultivation of microalgal and cyanobacterial strains is crucial for the biological conversion of CO2 and potential CO2 mitigation to challenge global warming. To overcome the economic barriers, the production of value-added chemicals was desired by compensating for the overall processing cost. Here, we engineered cyanobacteria for photosynthetic squalene production and cultivated them in a scalable photobioreactor using industrial flue gas. First, an inducer-free gene expression system was developed for the cyanobacteria to lower production const. Then, the recombinant cyanobacteria were cultivated in a closed photobioreactor (100 L) using flue gas (5% CO2) as the sole carbon source under natural sunlight as the only energy source. Seasonal light intensities and temperatures were analyzed along with cyanobacterial cell growth and squalene production in August and October 2019. As a result, the effective irradiation hours were the most critical factor for the large-scale cultivation of cyanobacteria. Thus, an automated photobioprocess system will be developed based on the regional light sources.

Exosomes, membrane-bound vesicles having a diameter of 30–150nm, are secreted by most cell types, including tumor cells. These vesicles mediate intercellular communication by transferring bioactive molecules (including a variety of proteins and nucleic acids) from donor to recipient cells. Notably, tumor cells secrete more exosome into microenvironment than nontumoral cells. Tumor-derived exosomes are enriched in molecular and genetic traits of tumor cells that facilitate cancer initiation, progression, and metastasis. Due to their abundance and stability, exosomes are one of the promising diagnostic and prognostic biomarkers for various cancers. Despite promising clinical potential, exosome-based diagnostics remains challenging because of the heterogeneity of exosome and difficulties in the profiling of exosomal contents. Therefore, there is a necessity to develop the sensing platform for molecular fingerprinting of exosomes toward clinical application. In this critical review, we explore the emerging use of nanoplasmonic biosensors to detect exosomal biomarkers and the application of this technology to the diagnosis and monitoring of cancer.

Microalgae have piqued renewed interest as a sustainable biofuel feedstock owing to their high CO2 conversion efficiency. However, the major limitation of microalga-based biofuel production is low productivity. In this study, CO2 in flue gas emitted from the coal-fired power plants was fixed through mass microalgal cultivation using only sunlight as an energy source. To minimize the cost and energy required to supply the flue gas and efficiently utilize the microalgal biomass, a polycarbonate (PC) greenhouse and polymeric photobioreactors were installed near the power plant stack. Four different microalgal strains (Chlamydomonas reinhardtii, Chlorella sorokiniana, Neochloris oleoabundans, and Neochloris oleoabundans #13) were subjected to semi-continuous culturing for 1 month. The maximum biomass productivity was achieved by the N. oleoabundans #13 strain (0.703 g L−1 day−1). Additionally, polymerase chain reaction analysis revealed that the individual microalgal culture was not cross-contaminated with other microalgal cultures in this cultivation system, owing to the structural properties of photobioreactor comprising individual modules. The lipid content and calorific productivity of N. oleoabundans #13 biomass were 45.70% and 3.553 kJ L−1 day−1, respectively, which indicate satisfactory performance of biomass as a direct combustion fuel. The CO2 fixation rate, which was calculated based on the carbon content in the biomass, was 0.309 g CO2 L−1 day−1. Therefore, large amounts of CO2 can be reduced using the large-scale microalgal cultivation system, which enables efficient biological CO2 conversion and maximizes microalgal biomass utilization.

In response to the energy crisis microalgae are a promising feedstock for biofuel production. The use of metabolic engineering to improve yields of biofuel-related lipid components in microalgae, without affecting cell growth, is now recognized as a promising and more economically feasible approach to develop more sustainable energy sources. For this, we generated Chlamydomonas mutant strains using CRISPR-Cas9 technology to knockout a gene involved in fatty acid (FA) degradation. In the knockout mutant, total lipid accumulated up to 28% of dried biomass, while that of wild-type (WT) was 22%. This increase was also accompanied by a noticeable shift in FA composition with an increase up to 27.2% in the C18:1 proportion. In addition, these mutants showed comparable growth rate to the WT, indicating that inhibiting lipid catabolism through gene editing technology is a promising strategy to develop microalgal strains for biofuel production.

Summary Designing synthetic pathways for efficient CO2 fixation and conversion is essential for sustainable chemical production. Here we have designed a synthetic acetate‐acetyl‐CoA/malonyl‐CoA (AAM) bypass to overcome an enzymatic activity of pyruvate dehydrogenase complex. This synthetic pathway utilizes acetate assimilation and carbon rearrangements using a methyl malonyl‐CoA carboxyltransferase. We demonstrated direct conversion of CO2 into acetyl‐CoA‐derived acetone as an example in photosynthetic Synechococcus elongatus PCC 7942 by increasing the acetyl‐CoA pools. The engineered cyanobacterial strain with the AAM‐bypass produced 0.41 g/L of acetone at 0.71 m/day of molar productivity. This work clearly shows that the synthetic pyruvate dehydrogenase bypass (AAM‐bypass) is a key factor for the high‐level production of an acetyl‐CoA‐derived chemical in photosynthetic organisms.

The urinary exosomal miRNAs are recently emerging prostate cancer (PC)-associated biomarkers for the early-stage diagnosis and prognosis due to their non-invasiveness, inherent stability and the representation of the status of the originated cells. However, developing a urinary exosomal miRNA detection method with high accuracy is challenging because of the low abundance and high sequence homology of miRNAs. Herein, we present a quantitative and label-free miRNA sensing platform using surface-enhanced Raman scattering (SERS) based on three-dimensional (3D) hierarchical plasmonic nano-architecture to detect urinary exosomal miRNAs. This hierarchical nanostructure is constructed by self-assembly between target-complementary DNA probes-conjugated gold nanoparticles and head-flocked gold nanopillars in the presence of the target miRNAs, creating numerous 3D plasmonic hot-spots inducing exceedingly high amplification of SERS signals. This 3D SERS biosensor achieved ∼10 aM detection limits for the target miRNAs (miR-10a and miR-21), which is over 1000-fold more sensitive than previously reported miRNA sensors without the requirement of any labelling or pre-treatment steps. Finally, the clinical validation using urinary samples revealed that our 3D SERS sensor discriminates PC patients from healthy control with high diagnostic accuracy (0.93) based on the differential expression level of urinary exosomal miRNAs. These outputs demonstrate that our SERS sensor based on 3D hierarchical nano-architecture can offer facile, accurate and rapid methods to measure miRNA expression and is helpful for the diagnosis of various diseases.

Microalgae are recognized as cell factories enriched with biochemicals suitable as feedstock for bio-energy, food, feed, pharmaceuticals, and nutraceuticals applications. The industrial application of microalgae is challenging due to hurdles associated with mass cultivation and biomass recovery. The scale-up production of microalgal biomass in freshwater is not a sustainable solution due to the projected increase of freshwater demands in the coming years. Microalgae cultivation in wastewater is encouraged in recent years for sustainable bioeconomy from biorefinery processes. Wastewater from the food industry is a less-toxic growth medium for microalgal biomass production. Traditional wastewater treatment and management processes are expensive; hence it is highly relevant to use low-cost wastewater treatment processes with revenue generation through different products. Microalgae are accepted as potential biocatalysts for the bioremediation of wastewater. Microalgae based purification of wastewater technology could be a universal alternative solution for the recovery of resources from wastewater for low-cost biomass feedstock for industry. This review highlights the importance of microalgal biomass production in food processing wastewater, their characteristics, and different microalgal cultivation methods, followed by nutrient absorption mechanisms. Towards the end of the review, different microalgae biomass harvesting processes with biorefinery products, and void gaps that tend to hinder the biomass production with future perspectives will be intended. Thus, the review could claim to be valuable for sustainable microalgae biomass production for eco-friendly bioproduct conversions.

Microalgae are unicellular photosynthetic organisms capable of producing high-value metabolites like carbohydrates, lipids, proteins, polyunsaturated fatty acids, vitamins, pigments, and other high-value metabolites. Microalgal biomass gained more interest for the production of nutraceuticals, pharmaceuticals, therapeutics, food supplements, feed, biofuel, bio-fertilizers, etc. due to its high lipid and other high-value metabolite content. Microalgal biomass has the potential to convert trapped solar energy to organic materials and potential metabolites of nutraceutical and industrial interest. They have higher efficiency to fix carbon dioxide (CO2) and subsequently convert it into biomass and compounds of potential interest. However, to make microalgae a potential industrial candidate, cost-effective cultivation systems and harvesting methods for increasing biomass yield and reducing the cost of downstream processing have become extremely urgent and important. In this review, the current development in different microalgal cultivation systems and harvesting methods has been discussed.

Blood-based detection of Alzheimer's disease (AD) biomarker has become a prominent method for diagnosis of AD which can replace the complex and invasive cerebrospinal fluid (CSF)-based diagnostic method. However, the application of blood AD biomarker in actual AD diagnosis is hampered by the extremely low concentration of biomarkers in blood, as well as the existence of interfering proteins. Therefore, it is essential to develop a sensitive and specific detection platform to achieve blood-based diagnosis of AD. Here, a surface-enhanced Raman scattering (SERS)-based sensor is developed for the quantitative determination of tau protein in the plasma of AD patients. To acquire femtomolar-level detection limit, this platform involves the use of half antibody fragment immobilized onto head-flocked gold nanopillar SERS substrates and SERS-nanotags. The small size of the half antibody fragment maximizes the effect of plasmon coupling, by reducing the distance between SERS substrates and SERS-nanotags. Also, the use of half antibody fragment improves the antigen recognition ability by immobilizing the antibody with high density and efficient orientation of the antibody. The sensor using these characteristics showed a low detection limit of 3.21 fM and a wide detection range (10 fM - 1 μM). The platform was also able to accurately quantify the tau protein in the clinical plasma sample and correctly distinguish the AD patient from the healthy control. The ultrasensitive and specific SERS immunoassay platform facilitates accurate and early detection of AD biomarkers and can serve as a valuable tool for simple point-of-care testing in clinical diagnosis.

Owing to its strong antioxidant properties, astaxanthin has a high market price in the nutraceutical and pharmaceutical fields, and its demand is increasing. Furthermore, with an increase in the demand for green technology, astaxanthin production through direct CO

Bisphenol A (or BPA) is a toxic endocrine disrupting chemical that is released into the environment through modern manufacturing practices. BPA can disrupt the production, function and activity of endogenous hormones causing irregularity in the hypothalamus-pituitary-gonadal glands and also the pituitary-adrenal function. BPA has immuno-suppression activity and can downregulate T cells and antioxidant genes. The genotoxicity and cytotoxicity of BPA is paramount and therefore, there is an immediate need to properly detect and remediate its influence. In this review, we discuss the toxic effects of BPA on different metabolic systems in the human body, followed by its mechanism of action. Various novel detection techniques (LC-MS, GC-MS, capillary electrophoresis, immunoassay and sensors) involving a pretreatment step (liquid-liquid microextraction and molecularly imprinted solid-phase extraction) have also been detailed. Mechanisms of various remediation strategies, including biodegradation using native enzymes, membrane separation processes, photocatalytic oxidation, use of nanosorbents and thermal degradation has been detailed. An overview of the global regulations pertaining to BPA has been presented. More investigations are required on the efficiency of integrated remediation technologies rather than standalone methods for BPA removal. The effect of processing operations on BPA in food matrices is also warranted to restrict its transport into food products.

Haematococcus pluvialis has attracted interest as a bio-platform for producing omega-3 fatty acids (ω-3 FA) and astaxanthin that have a great potential as anti-inflammatory drugs. This study aimed to concurrently enhance the CO

The microalgae Haematococcus pluvialis biologically converts CO2 into natural astaxanthin that possesses a strong antioxidant activity; its low carbon footprint and economic viability have allowed it to garner great attention. However, low efficiency of the cultivation process is a major hurdle in its commercial production. Here, additional nitrogen was provided to fully grown cells to induce efficient cyst germination, thereby rapidly increasing the number of cells containing astaxanthin. After germination, these cells were rapidly converted from zooids to cysts by nitrogen depletion, while maintaining a steady astaxanthin content of 5.5%. Consequently, a 2.1-fold increase in astaxanthin productivity in comparison with that in a batch culture was achieved. Moreover, the germination-based semi-continuous process yielded 2.6 times higher astaxanthin productivity in a large-scale culture using power plant flue gas and a polymeric photobioreactor. This study provides a promising cultivation strategy for the commercial mass production of natural astaxanthin.

The extraction of diverse thermolabile but highly value-added chemicals entrapped in the robust cell wall of algal biomass has remained a remarkable challenge. This study investigated the one-pot, ...

Reverse transcription – quantitative polymerase chain reaction (RT-qPCR) is conventionally used method to analyze oncogenes, infected DNAs, and mutated tumor associated genes. However it is hard to detect rare genetic targets since the disturbance of undesired amplification often overrides the reaction of very few targets in a myriad of interfering genes. To solve the limitation, we developed primerimmobilized network (PIN) probe RT-qPCR which can detect target RNA with high selectivity and sensitivity. To conduct PIN probe RT-qPCR with high efficiency, design of probe, concentration of immobilized probe and qPCR condition were optimized. The LOD of PIN probe RT-qPCR was 40pg per particle with 89.2% efficiency. When extremely low concentration of RNA was used, result of PIN probe RTqPCR was showed “on/off” signal. Also, target was confirmed only in the “on” particle. The interference effects by non-target PCR products were minimized by target-capturing and washing process in the RT. Using PIN probe RT-qPCR, we successfully detected target RNA in a sample which has a ratio of 1:100,000 (positive RNA : negative RNA).

Current research aimed to increase mixotrophic biomass from various organic carbon sources by exploring best light conditions. Three substrates glucose, acetic acid and glycerol were studied for their effects on mixotrophic microalgae cultivation under four light conditions. Light irradiance exhibited variability in growth response and photosynthetic efficiency based on type of substrates used in mixotrophic growth. Each substrate showed variability in light requirements for their effective assimilations. From growth responses, glucose and acetic acid respectively exhibited heterotrophic and mixotrophic (better growth in light) natures. Continuous light-deficient condition was adequate for effective mixotrophic growth as well as energy saving for glucose. However, light-sufficient condition required for effective acetic acid supported mixotrophic growth. Mixotrophic benefits from glycerol and its uptake by Chlorella protothecoides was negligible in all light conditions. Investigation of heterotrophic biomass contribution by various substrates in overall mixotrophic yield, glucose offered maximum approx. 43% contribution.

It is envisaged that the utilization of lignocellulosic biomass for ethanol production for transport sector, would make cellulases the most demanded industrial enzyme. The greatest potential of cellulolytic enzymes lies in ethanol production from biomass by enzymatic hydrolysis of cellulose but low thermostability and low titer of cellulase production resulting into high cost of the enzyme which is the major set-back. A number of research groups are working on cellulase to improve its thermostability so as to be able to perform hydrolysis at elevated temperatures which would eventually increase the efficiency of cellulose hydrolysis. The technologies developed from lignocellulosic biomass via cellulose hydrolysis promise environmental and economical sustainability in the long run along with non-dependence on nonrenewable energy source. This review deals with the important sources of thermostable cellulases, mechanism, its regulation, strategies to enhance the thermostability further with respect to its importance for biofuel applications.

An acidic cultivation strategy was developed to prevent contamination of a lethal fungus Paraphysoderma sedebokerensis in Haematococcus pluvialis culture for astaxanthin production. Instead of generally used neutral pH, an acidic condition (pH 4) was applied to the cultivation, resulting in a significant inhibition of the fungal contamination. This could be ascribed to the acidity-associated denaturation of a surface protein of P. sedebokerensis, which plays an important role in recognition of H. pluvialis. Stress relief strategies including stepwise light irradiation and naturally occurring nitrogen deficiency were employed in the induction stage to minimize the reduction of astaxanthin production caused by acidic pH. Accordingly, an astaxanthin titer of 84.8 mg L−1 was obtained, which is 141-fold of that from the completely contaminated culture and double of that without the stress relief methods. This strategy provides a persistent contamination control method that can be used for practical astaxanthin production by H. pluvialis.

Metallic plasmonic nanoparticles generate surface-enhanced Raman Scattering (SERS) for wide sensing applications of biomolecules, gas and environmental contaminants. However, the metallic materials cause high thermal radiation during laser excitation in the opto-microfluidic systems and give rise to temporal intensity fluctuations, which is called blinking effects in SERS spectra. This work developed nanocomposite consisting of graphene oxide (GO) and gold nanoparticles (AuNPs) with high thermal stability and low thermal radiation, which provided plasmonic resonance while reduced blinking effect for SERS-based sensing in the microfluidic detection system. The system was applied to detect kanamycin in drinking water, orange juice, and milk by using Texas Red-dye conjugated Beacon aptamer, where the aptamer was designed to be specific and switchable in kanamycin recognition. The sensor was reusable, and its limit of detection was 0.75 nM in a linear range of 1 nM to 100 nM. The microfluidic SERS detection system can be potentially used for sensitive and reliable assays of small molecules.