Comparative Proteome Profiling of Extracellular Vesicles from Three Growth Phases of Haematococcus pluvialis under High Light and Sodium Acetate Stresses

Extracellular vesicles (EVs) are nano-sized particles involved in intercellular communications that intrinsically possess many attributes as a modern drug delivery platform. Haematococcus pluvialis-derived EVs (HpEVs) can be potentially exploited as a high-value-added bioproduct during astaxanthin production. The encapsulation of HpEV cargo is a crucial key for the determination of their biological functions and therapeutic potentials. However, little is known about the composition of HpEVs, limiting insights into their biological properties and application characteristics. This study examined the protein composition of HpEVs from three growth phases of H. pluvialis grown under high light (350 µmol·m-2·s-1) and sodium acetate (45 mM) stresses. A total of 2038 proteins were identified, the majority of which were associated with biological processes including signal transduction, cell proliferation, cell metabolism, and the cell response to stress. Comparative analysis indicated that H. pluvialis cells sort variant proteins into HpEVs at different physiological states. It was revealed that HpEVs from the early growth stage of H. pluvialis contain more proteins associated with cellular functions involved in primary metabolite, cell division, and cellular energy metabolism, while HpEVs from the late growth stage of H. pluvialis were enriched in proteins involved in cell wall synthesis and secondary metabolism. This is the first study to report and compare the protein composition of HpEVs from different growth stages of H. pluvialis, providing important information on the development and production of functional microalgal-derived EVs.

Unraveling the Impact of Extracellular Vesicle-Depleted Serum on Endothelial Cell Characteristics over Time

Extracellular vesicles (EVs) are produced by all kinds of cells, including endothelial cells. It has been observed that EVs present in fetal bovine serum (FBS), broadly used in cell culture, can be a confounding factor and lead to misinterpretation of results. To investigate this phenomenon, human brain microvascular endothelial cells (HBMECs) were cultured for 2 or 24 h in the presence of EV-depleted FBS (EVdS). Cell death, gene and protein expression, and the presence of EVs isolated from these cells were evaluated. The uptake of EVs, intercellular adhesion molecule 1 (ICAM-1) expression, and monocyte adhesion to endothelial cells exposed to EVs were also evaluated. Our results revealed higher apoptosis rates in cells cultured with EVdS for 2 and 24 h. There was an increase in interleukin 8 (IL8) expression after 2 h and a decrease in interleukin 6 (IL6) and IL8 expression after 24 h of culture. Among the proteins identified in EVs isolated from cells cultured for 2 h (EV2h), several were related to ribosomes and carbon metabolism. EVs from cells cultured for 24 h (EV24h) presented a protein profile associated with cell adhesion and platelet activation. Additionally, HBMECs exhibited increased uptake of EV2h. Treatment of endothelial cells with EV2h resulted in greater ICAM-1 expression and greater adherence to monocytes than did treatment with EV24h. According to our data, HBMEC cultivated with EVdS produce EVs with different physical characteristics and protein levels that vary over time.

Extracellular vesicles involved in growth regulation and metabolic modulation in Haematococcus pluvialis

BACKGROUND

Microalgae-derived extracellular vesicles (EVs), which transfer their cargos to the extracellular environment to affect recipient cells, play important roles in microalgal growth and environmental adaptation. And, they are also considered as sustainable and renewable bioresources of delivery nanocarrier for bioactive molecules and/or artificial drug molecules. However, their molecular composition and functions remain poorly understood.

RESULTS

In this study, isolation, characterization, and functional verification of Haematococcus pluvialis-derived EVs (HpEVs) were performed. The results indicated that HpEVs with typical EV morphology and size were secreted by H. pluvialis cells during the whole period of growth and accumulated in the culture medium. Cellular uptake of HpEVs by H. pluvialis was confirmed, and their roles in regulation of growth and various physiological processes of the recipient cells were also characterized. The short-term inhibition of HpEV secretion results in the accumulation of functional cellular components of HpEVs, thereby altering the biological response of these cells at the molecular level. Meanwhile, continuously inhibiting the secretion of HpEVs negatively influenced growth, and fatty acid and astaxanthin accumulation in H. pluvialis. Small RNA high-throughput sequencing was further performed to determine the miRNA cargoes and compelling details in HpEVs in depth. Comparative analysis revealed commonalities and differences in miRNA species and expression levels in three stages of HpEVs. A total of 163 mature miRNAs were identified with a few unique miRNAs reveal the highest expression levels, and miRNA expression profile of the HpEVs exhibited a clear stage-specific pattern. Moreover, a total of 12 differentially expressed miRNAs were identified and their target genes were classified to cell cycle control, lipid transport and metabolism, secondary metabolites biosynthesis and so on.

CONCLUSION

It was therefore proposed that cargos of HpEVs, including miRNA constituents, were suggested potential roles in modulate cell physiological state of H. pluvialis. To summarize, this work uncovers the intercellular communication and metabolism regulation functions of HpEVs.

Applications of microalga-powered microrobots in targeted drug delivery

Over the past decade, researchers have proposed a new class of drug delivery systems, bio-hybrid micro-robots, designed with a variety of living cell-driven micro-robots that utilize the unique mobility of natural organisms (bacteria, cells, exosomes, etc.) to transport effective drugs. Microalgae are considered potential drug delivery carriers. Recent studies have shown that microalga-based drug delivery systems exhibit excellent biocompatibility. In addition, microalgae have a large surfactant area, phototaxis, oxygen production, and other characteristics, so they are used as a carrier for the treatment of bacterial infections, cancer, etc. This review summarizes the modification of microalgae including click chemistry and electrostatic adsorption, and can improve the drug loading efficiency through dehydration and hydration strategies. The prepared microalgal drug delivery system can be targeted to different organs by different dosing methods or using external forces. Finally, it summarizes its antibacterial (gastritis, periodontitis, skin wound inflammation, etc.) and antitumor applications.

Filtration-based technologies for isolation, purification and analysis of extracellular vesicles

The involvement of extracellular vesicles (EVs) in cellular communication with multifactorial and multifaceted biological activity has generated significant interest, highlighting their potential diagnostic and therapeutic applications. EVs are found in nearly all biological fluids creating a broad spectrum of where potential disease markers can be found for liquid biopsy development and what subtypes can be used for treatment of diseases. Complexity of biological fluids has generated a variety of different approaches for EV isolation and identification that may in one way or another be most optimal for research studies or clinical use. Each approach has its own advantages and disadvantages, significance of which can be evaluated depending on the end goal of the study. One of the methods is based on filtration which has received attention in the past years due its versatility, low cost and other advantages. Introduction of different approaches for EV capture and analysis that are based on filtration gave rise to new subcategories of filtration techniques which are presented in this overview. Miniaturization and combination of filtration-based approaches with microfluidics is also highlighted due its future prospects in healthcare, especially point-of-need technologies.

Pathological and Therapeutic Significance of Tumor-Derived Extracellular Vesicles in Cancer Cell Migration and Metastasis

The infiltration of primary tumors and metastasis formation at distant sites strongly impact the prognosis and the quality of life of cancer patients. Current therapies including surgery, radiotherapy, and chemotherapy are limited in targeting the complex cell migration mechanisms responsible for cancer cell invasiveness and metastasis. A better understanding of these mechanisms and the development of new therapies are urgently needed. Extracellular vesicles (EVs) are lipid-enveloped particles involved in inter-tissue and inter-cell communication. This review article focuses on the impact of EVs released by tumor cells, specifically on cancer cell migration and metastasis. We first introduce cell migration processes and EV subtypes, and we give an overview of how tumor-derived EVs (TDEVs) may impact cancer cell migration. Then, we discuss ongoing EV-based cancer therapeutic approaches, including the inhibition of general EV-related mechanisms as well as the use of EVs for anti-cancer drug delivery, focusing on the harnessing of TDEVs. We propose a protein-EV shuttle as a route alternative to secretion or cell membrane binding, influencing downstream signaling and the final effect on target cells, with strong implications in tumorigenesis. Finally, we highlight the pitfalls and limitations of therapeutic EV exploitation that must be overcome to realize the promise of EVs for cancer therapy.

Reconstructed membrane vesicles from the microalga Dunaliella as a potential drug delivery system

The aim of this biophysical study is to characterize reconstructed membrane vesicles obtained from microalgae in terms of their morphology, properties, composition, and ability to transport a model drug. The reconstructed vesicles were either emptied or non-emptied and exhibited a non-uniform distribution of spherical surface structures that could be associated with surface coat proteins, while in between there were pore-like structures of up to 10 nm that could contribute to permeability. The reconstructed vesicles were very soft and hydrophilic, which could be attributed to their composition. The vesicles were rich in proteins and were mostly derived from the cytoplasm and chloroplasts. We demonstrated that all lipid classes of D. tertiolecta are involved in the formation of the reconstructed membrane vesicles, where they play fundamental role to maintain the vesicle structure. The vesicles appeared to be permeable to calcein, impermeable to FITC-ovalbumin, and semipermeable to FITC-concanavalin A, which may be due to a specific surface interaction with glucose/mannose units that could serve as a basis for the development of drug carriers. Finally, the reconstructed membrane vesicles could pave a new way as sustainable and environmentally friendly marine bioinspired carriers and serve for studies on microtransport of materials and membrane-related processes contributing to advances in life sciences and biotechnology.

Endogenous Lipid Carriers—Bench-to-Bedside Roadblocks in Production and Drug Loading of Exosomes

Exosomes are cell-derived, nano-sized extracellular vesicles comprising a lipid bilayer membrane that encapsulates several biological components, such as nucleic acids, lipids, and proteins. The role of exosomes in cell–cell communication and cargo transport has made them promising candidates in drug delivery for an array of diseases. Despite several research and review papers describing the salient features of exosomes as nanocarriers for drug delivery, there are no FDA-approved commercial therapeutics based on exosomes. Several fundamental challenges, such as the large-scale production and reproducibility of batches, have hindered the bench-to-bedside translation of exosomes. In fact, compatibility and poor drug loading sabotage the possibility of delivering several drug molecules. This review provides an overview of the challenges and summarizes the potential solutions/approaches to facilitate the clinical development of exosomal nanocarriers.

Cryo-electron microscopy of extracellular vesicles associated with the marine toxic dinoflagellate Alexandrium minutum

Extracellular Vesicles (EVs) are likely an important strategy of transport and communication in marine microbial community. Their isolation and characterization from axenic culture of microbial eukaryotes represents a technological challenge not fully solved. Here, for the first time, we isolated EVs from a near-axenic culture of the toxic dinoflagellate Alexandrium minutum. Pictures of the isolated vesicles were done with Cryo TEM (Cryogenic Transmission Electron Microscopy). Based on their morphotype the EVs were clustered in five major groups (rounded, rounded electron-dense, lumen electron-dense, double and irregular) and each EV was measured resulting in an average size of 0.36 µm of diameter. Taking in account that in prokaryotes it has been demonstrated that EVs play an important role in the mechanism of toxicity, this descriptive work aims to be the first step to study the possible role of EVs in the toxicity of dinoflagellates.

High-Yield Production of Extracellular Vesicle Subpopulations with Constant Quality Using Batch-Refeed Cultures

The conventional manufacturing of extracellular vesicles (EVs) is characterized by low yields and batch-to-batch variability, hampering fundamental research on EVs and their practical applications. Perfusion operations have huge potential to address these limitations and increase the productivity and quality of EVs. In this study, perfusion cultures are simulated with batch-refeed systems and their productivity is compared with that achieved using batch cultures. It is shown that a shift from batch to batch-refeed system can increase the space-time yields of a target EV subpopulation characterized by CD81 and CD63 biomarkers by threefold. Moreover, it is demonstrated that the method facilitates the consistent production of the target EVs from cells maintained under constant conditions for 13 days. These results indicate that the use of perfusion cultures is a promising strategy to increase the manufacturing yield of EVs and control the production of specific EV subpopulations with constant quality attributes, thereby improving reproducibility.

Alternative biological sources for extracellular vesicles production and purification strategies for process scale-up

Extracellular vesicles (EVs) are phospholipidic bi-layer enclosed nanoparticles secreted naturally by all cell types. They are attracting increasing attention in the fields of nanomedicine, nutraceutics and cosmetics as biocompatible carriers for drug delivery, with intrinsic properties beneficial to human health. Scientific work now focuses on developing techniques for isolating EVs that can translate into industrial-scale production and meet rigorous clinical requirements. The science of EVs is ongoing, and many pitfalls must be addressed, such as the requirement for standard, reproducible, inexpensive, and Good Manufacturing Practices (GMP) adherent EV processing techniques. Researchers are exploring the use of alternative sources to EVs derived from mammalian cultures, such as plant EVs, as well as the use of bacteria, algae and milk. Regarding the downstream processing of EVs, many alternative techniques to the ultracentrifugation (UC) protocols most commonly used in the laboratory are emerging. In the context of process scale-up, membrane-based processes for isolation and purification of EVs are the most promising, either as stand-alone processes or in combination with chromatographic techniques. This review discusses current trends on EVs source selection and EVs downstream processing techniques, with a focus on plant-derived EVs and membrane-based techniques for EVs enrichment.

Biosynthesis and Antimicrobial Evaluation of Zinc Oxide Nanoparticles Using Chlorella vulgaris Biomass against Multidrug-Resistant Pathogens

The rampant increase in antibiotic resistance has created a global barrier to the treatment of multidrug-resistant infections. Biogenic synthesis of nanomaterials is a novel approach to producing nanostructures with biological resources. Algae are known to be clean, nontoxic, cost-beneficial, and environmentally acceptable. Chlorella vulgaris is a popular microalga for its broad applications in food, supplements, pharmaceuticals, and cosmetics. In this study, we used Chlorella vulgaris biomass lyophilized powder as our green resource for the biosynthesis ZnONPs. Chlorella vulgaris culture was harvested at the end of the logarithmic phase, and the biomass was lyophilized. ZnONPs were synthesized using lyophilized biomass and 20 mM zinc acetate dihydrate at a temperature of 70 °C and continuous stirring in a water bath overnight. At the end of the reaction, UV-Vis absorption of colloidal suspension proved the synthesis of ZnONPs. The physicochemical characteristics of nanoparticles were analyzed using FTIR, DLS, TEM, and XRD. Based on FTIR spectra. The antibacterial activity of green synthesized nanostructures was evaluated against methicillin-resistant staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE). The synthesized ZnONPs have oxygen-containing groups on the surface that show the synthesized nanoparticles' stabilization. The Zeta potential was -27.4 mV, and the mean particle size was measured as 33.4 nanometers. Biogenic ZnONPs produced in this method have a notable size distribution and excellent surface energy, which can have vast applications like antimicrobial potential in pharmaceuticals as topical forms. Additionally, in order to evaluate the antimicrobial activity of ZnO nanoparticles, we used MRSA and VRE strains and the results showed the anti-MRSA activity at 400 and 625 μg mL^-1, respectively. Thus, these biogenic ZnO nanoparticles revealed a substantial antibacterial effect against multidrug-resistant pathogens, associated with several serious systemic infections, and have the potential as an antimicrobial agent for further study.

High-Yield Separation of Extracellular Vesicles Using Programmable Zwitterionic Coacervates

Programmable coacervates based on zwitterionic polymers are designed as dynamic materials for ion exchange bioseparation. These coacervates are proposed as promising materials for the purification of soft nanoparticles such as liposomes and extracellular vesicles (EVs). It is shown that the stimulus-responsiveness of the coacervates and the recruitment of desired molecules can be independently programmed by polymer design. Moreover, the polymeric coacervates can recruit and release intact liposomes, human EVs, and nanoalgosomes in high yields and separate vesicles from different types of impurities, including proteins and nucleic acids. This approach combines the speed and simplicity of precipitation methods and the programmability of chromatography with the gentleness of aqueous two-phase separation, thereby guaranteeing product stability. This material represents a promising alternative for providing a low-shear, gentle, and selective purification method for EVs.

Production of recombinant and therapeutic proteins in microalgae

Microalgae is emerging as a promising platform for the production of recombinant proteins of therapeutic importance. Since microalgae are safe for oral consumption and some microalgal species can form extracellular vesicles, they can potentially be used as edible vaccines or drug-delivery vehicles in addition to their status as naturally rich sources of nutraceutical bioproducts. This article focuses on recent advances in the field of recombinant protein production in microalgae, and developments toward the use of microalgae as a vehicle for drug delivery.

A critical review on biomass-based sustainable biorefineries using nanobiocatalysts: Opportunities, challenges, and future perspectives

Biocatalysts, including live microbial cells/enzymes, have been considered a predominant and advantageous tool for effectively transforming biomass into biofuels and valued biochemicals. However, high production costs, separation, and reusability limit its practical application. Immobilization of single and multi-enzymes by employing different nano-supports have gained massive attention because of its elevated exterior domain and high enzymatic performance. Application of nanobiocatalyst can overcome the drawbacks mainly, stability and reusability, thus reflecting the importance of biomass-based biorefinery to make it profitable and sustainable. This review provides an in-depth, comprehensive analysis of nanobiocatalysts systems concerning nano supports and biocatalytic performance characteristics. Furthermore, the effects of nanobiocatalyst on waste biomass to biofuel and valued bioproducts in the biorefinery approach and their critical assessment are discussed. Lastly, this review elaborates commercialization and market outlooks of the bioconversion process using nanobiocatalyst, followed by different strategies to overcome the limitations and future research directions on nanobiocatalytic-based industrial bioprocesses.

Large-scale production of extracellular vesicles: Report on the "massivEVs" ISEV workshop

Extracellular vesicles (EVs) large-scale production is a crucial point for the translation of EVs from discovery to application of EV-based products. In October 2021, the International Society for Extracellular Vesicles (ISEV), along with support by the FET-OPEN projects, "The Extracellular Vesicle Foundry" (evFOUNDRY) and "Extracellular vesicles from a natural source for tailor-made nanomaterials" (VES4US), organized a workshop entitled "massivEVs" to discuss the potential challenges for translation of EV-based products. This report gives an overview of the topics discussed during "massivEVs", the most important points raised, and the points of consensus reached after discussion among academia and industry representatives. Overall, the review of the existing EV manufacturing, upscaling challenges and directions for their resolution highlighted in the workshop painted an optimistic future for the expanding EV field.

A Novel Bioflocculant Produced by Cobetia marina MCCC1113: Optimization of Fermentation Conditions by Response Surface Methodology and Evaluation of Flocculation Performance when Harvesting Microalgae

A preliminary study was carried out to optimize the culture medium conditions for producing a novel microbial flocculant from the marine bacterial species Cobetia marina. The optimal glucose, yeast extract, and glutamate contents were 30, 10, and 2 g/l, respectively, while the optimal initial pH of the culture medium was determined to be 8. Following response surface optimization, the maximum bioflocculant production level of 1.36 g/l was achieved, which was 43.40% higher than the original culture medium. Within 5 min, a 20.0% (v/v) dosage of the yielded bioflocculant applied to algal cultures resulted in the highest flocculating efficiency of 93.9% with Spirulina platensis. The bioflocculant from C. marina MCCC1113 may have promising application potential for highly productive microalgae collection, according to the findings of this study.

Manufactured extracellular vesicles as human therapeutics: challenges, advances, and opportunities

Extracellular vesicles (EVs) have evolved across all phyla as an intercellular communication system. There are intrinsic advantages of leveraging this capability to deliver therapeutic cargo to treat disease, which have been demonstrated in numerous in vivo studies. As with other new modalities, the challenge has now shifted from proof of concept to developing reliable and efficient large-scale infrastructure to manufacture consistently pure and potent drug for broad-based patient access. This review focuses on how this challenge has been met with both existing and emerging technology platforms that are making impressive strides in the industrialization of EV manufacturing. In addition, we also highlight the gaps and opportunities that are beginning to be explored and addressed to hasten ushering in the era of therapeutic EVs.

Interaction between Microalgae P. tricornutum and Bacteria Thalassospira sp. for Removal of Bisphenols from Conditioned Media

We studied the efficiency of three culture series of the microalgae Phaeodactylum tricornutum (P. tricornutum) and bacteria Thalassospira sp. (axenic microalgae, bacterial culture and co-culture of the two) in removing bisphenols (BPs) from their growth medium. Bacteria were identified by 16S ribosomal RNA polymerase chain reaction (16S rRNA PCR). The microorganism growth rate was determined by flow cytometry. Cultures and isolates of their small cellular particles (SCPs) were imaged by scanning electron microscopy (SEM) and cryogenic transmission electron microscopy (Cryo-TEM). BPs were analyzed by gas chromatography coupled with tandem mass spectrometry (GC-MS/MS). Our results indicate that some organisms may have the ability to remove a specific pollutant with high efficiency. P. tricornutum in axenic culture and in mixed culture removed almost all (more than 99%) of BPC2. Notable differences in the removal of 8 out of 18 BPs between the axenic, mixed and bacterial cultures were found. The overall removals of BPs in axenic P. tricornutum, mixed and bacterial cultures were 11%, 18% and 10%, respectively. Finding the respective organisms and creating microbe societies seems to be key for the improvement of wastewater treatment. As a possible mediating factor, numerous small cellular particles from all three cultures were detected by electron microscopy. Further research on the mechanisms of interspecies communication is needed to advance the understanding of microbial communities at the nano-level.

Extracellular Vesicles From Microalgae: Uptake Studies in Human Cells and Caenorhabditis elegans

Extracellular vesicles (EVs) are lipid membrane nano-sized vesicles secreted by various cell types for intercellular communication, found in all kingdoms of life. Nanoalgosomes are a subtype of EVs derived from microalgae with a sustainable biotechnological potential. To explore the uptake, distribution and persistence of nanoalgosomes in cells and living organisms, we separated them from a culture of the chlorophyte Tetraselmis chuii cells by tangential flow filtration (TFF), labelled them with different lipophilic dyes and characterized their biophysical attributes. Then we studied the cellular uptake of labelled nanoalgosomes in human cells and in C. elegans, demonstrating that they enter the cells through an energy dependent mechanism and are localized in the cytoplasm of specific cells, where they persist for days. Our data confirm that nanoalgosomes are actively uptaken in vitro by human cells and in vivo by C. elegans cells, supporting their exploitation as potential nanocarriers of bioactive compounds for theranostic applications.

Isolation of Extracellular Vesicles From Microalgae: A Renewable and Scalable Bioprocess

Extracellular vesicles (EVs) play a crucial role as potent signal transducers among cells, with the potential to operate cross-species and cross-kingdom communication. Nanoalgosomes are a subtype of EVs recently identified and isolated from microalgae. Microalgae represent a natural bioresource with the capacity to produce several secondary metabolites with a broad range of biological activities and commercial applications. The present study highlights the upstream and downstream processes required for the scalable production of nanoalgosomes from cultures of the marine microalgae Tetraselmis chuii. Different technical parameters, protocols, and conditions were assessed to improve EVs isolation by tangential flow filtration (TFF), aiming to enhance sample purity and yield. The optimization of the overall bioprocess was enhanced by quality control checks operated through robust biophysical and biochemical characterizations. Further, we showed the possibility of recycling by TFF microalgae cells post-EVs isolation for multiple EV production cycles. The present results highlight the potential of nanoalgosome production as a scalable, cost-effective bioprocess suitable for diverse scientific and industrial exploitations.

Rapid Characterization and Quantification of Extracellular Vesicles by Fluorescence-Based Microfluidic Diffusion Sizing

Extracellular vesicles (EVs) are emerging as promising diagnostic and therapeutic tools for a variety of diseases. The characterization of EVs requires a series of orthogonal techniques that are overall time- and material-consuming. Here, a microfluidic device is presented that exploits the combination of diffusion sizing and multiwavelength fluorescence detection to simultaneously provide information on EV size, concentration, and composition. The latter is achieved with the nonspecific staining of lipids and proteins combined with the specific staining of EV markers such as EV-associated tetraspanins via antibodies. The device can be operated as a single-step immunoassay thanks to the integrated separation and quantification of free and EV-bound fluorophores. This microfluidic technique is capable of detecting and quantifying components associated to EV subtypes and impurities and thus to measure EV purity in a time scale of minutes, requiring less than 5 µL of sample and minimal sample handling before the analysis. Moreover, the analysis is performed directly in solution without immobilization steps. Therefore, this method can accelerate screening of EV samples and aid the evaluation of sample reproducibility, representing an important complementary tool to the current array of biophysical methods for EV characterization, particularly valuable for instance for bioprocess development.

Euglena gracilis and Its Aqueous Extract Constructed With Chitosan-Hyaluronic Acid Hydrogel Facilitate Cutaneous Wound Healing in Mice Without Inducing Excessive Inflammatory Response

Naturally occurring compounds isolated from the microalga Euglena gracilis, such as polysaccharide paramylon, exhibit antimicrobial, anti-viral, antitumor, and anti-inflammatory activities. Whether live E. gracilis cells and its aqueous extract accelerate burn wound healing remains to be investigated. In this study, live E. gracilis cells and its aqueous extract were mixed with chitosan-hyaluronic acid hydrogel (CS/HA) to form cell + CS/HA and extract + CS/HA, which were then smeared onto the deeply burned skin of mice. The efficacy of these mixtures in accelerating wound healing was assessed through wound size reduction measurement, histological and immunofluorescence analyses, and serum pro-inflammatory cytokine level (INF-γ, IL-1β, and IL-6) determination. The live E. gracilis cells and its aqueous extract were found to facilitate wound healing by enhancing re-epithelization and reducing fibroplasia without stimulating excessive inflammatory response. In conclusion, live E. gracilis cells and its aqueous extract can be potentially used to treat cutaneous wounds.

Advanced Applications for Protein and Compounds from Microalgae

Algal species still show unrevealed and unexplored potentiality for the identification of new compounds. Photosynthetic organisms represent a valuable resource to exploit and sustain the urgent need of sustainable and green technologies. Particularly, unconventional organisms from extreme environments could hide properties to be employed in a wide range of biotechnology applications, due to their peculiar alleles, proteins, and molecules. In this review we report a detailed dissection about the latest and advanced applications of protein derived from algae. Furthermore, the innovative use of modified algae as bio-reactors to generate proteins or bioactive compounds was discussed. The latest progress about pharmaceutical applications, including the possibility to obtain drugs to counteract virus (as SARS-CoV-2) were also examined. The last paragraph will survey recent cases of the utilization of extremophiles as bio-factories for specific protein and molecule production.