Applications of Microdroplet Technology for Algal Biotechnology

Background: Microfluidics allows manipulation of small volumes of fluids through channels with dimensions of tens to hundreds of micrometres. Microdroplet technology is a form of microfluidics in which small (10-200 μm diameter) monodispersed aqueous droplets are generated, manipulated and analysed in various ways. This multidisciplinary field provides an exciting new platform for single-cell studies of both eukaryotic microalgae and cyanobacteria, with considerable potential for enhancing algal biotechnology. Methods: Growth of several species of microalgae has been studied in detail using microfluidics and microdroplets, and individual cells have been screened and sorted according to lipid content or ethanol production. Here we provide an overview of the devices, and the range of technological advances that are being pursued. Conclusion: Microdroplet technology is an emerging technology platform that can be used in a variety of applications, including monitoring of growth characteristics at the single-cell level and high-throughput screening of algal populations. Microdroplet platforms are being developed that will allow determination of individual cell characteristics to allow screening across a population, and thus to identify and select candidate cells for biotechnological feedstocks. As the potential of this emerging technical platform is recognized, the technology will become more accessible, so that it can soon be adopted and used by researchers, without the need for specialized prior knowledge of microfluidics or expensive equipment. The platform is amenable for use with species of both microalgae and cyanobacteria.SAC acknowledges the funding from EC within the EU FP7 DEMA project, grant agreement n°309086. RB was supported by a doctoral training grant from the Engineering and Physical Sciences Research Council (EPSRC) of the UK.This is the author accepted manuscript. The final version is available from Bentham Science via http://dx.doi.org/10.2174/221155010566616020200255

Droplet microfuidics for the highly controlled synthesis of branched gold nanoparticles

The synthesis of anisotropic metallic nanoparticles (NPs) has been a feld of intense and challenging research in the past decade. In this communication, we report on the reproducible and highly controllable synthesis of monodisperse branched gold nanoparticles in a droplet-based microfuidics platform. The process has been automated by adapting two diferent bulk synthetic strategies to microdroplets, acting as microreactors, for NP synthesis: a surfactant-free synthesis and a surfactantassisted synthesis. Microdroplets were generated in two diferent microfuidic devices designed to accommodate the requirements of both bulk syntheses. The epitaxial growth of AuNSTs inside the microdroplets allowed for a fne control of reagent mixing and local concentrations during particle formation. This is the frst time branched gold NPs have been synthesised in a microfuidics platform. The monodispersity of the product was comparable to the synthesis in bulk, proving the potential of this technology for the continuous synthesis of high quality anisotropic NPs with improved reproducibility.8FAPESP – Fundação de Amparo à Pesquisa Do Estado De São Paulo2015/01685-2; 2016/02414-

Droplet microfluidics for the highly controlled synthesis of branched gold nanoparticles

The synthesis of anisotropic metallic nanoparticles (NPs) has been a field of intense and challenging research in the past decade. In this communication, we report on the reproducible and highly controllable synthesis of monodisperse branched gold nanoparticles in a droplet-based microfluidics platform. The process has been automated by adapting two different bulk synthetic strategies to microdroplets, acting as microreactors, for NP synthesis: a surfactant-free synthesis and a surfactant-assisted synthesis. Microdroplets were generated in two different microfluidic devices designed to accommodate the requirements of both bulk syntheses. The epitaxial growth of AuNSTs inside the microdroplets allowed for a fine control of reagent mixing and local concentrations during particle formation. This is the first time branched gold NPs have been synthesised in a microfluidics platform. The monodispersity of the product was comparable to the synthesis in bulk, proving the potential of this technology for the continuous synthesis of high quality anisotropic NPs with improved reproducibility.This work was supported by EU Framework Programme for Research and Innovation H2020 COFUND, Grant Agreement 713640 (SAC) and by FAPESP, project No. 2015/01685-2 (PTB). MGO acknowledges FAPESP, project No 2016/02414-5

High-throughput detection of ethanol-producing cyanobacteria in a microdroplet platform.

Ethanol production by microorganisms is an important renewable energy source. Most processes involve fermentation of sugars from plant feedstock, but there is increasing interest in direct ethanol production by photosynthetic organisms. To facilitate this, a high-throughput screening technique for the detection of ethanol is required. Here, a method for the quantitative detection of ethanol in a microdroplet-based platform is described that can be used for screening cyanobacterial strains to identify those with the highest ethanol productivity levels. The detection of ethanol by enzymatic assay was optimized both in bulk and in microdroplets. In parallel, the encapsulation of engineered ethanol-producing cyanobacteria in microdroplets and their growth dynamics in microdroplet reservoirs were demonstrated. The combination of modular microdroplet operations including droplet generation for cyanobacteria encapsulation, droplet re-injection and pico-injection, and laser-induced fluorescence, were used to create this new platform to screen genetically engineered strains of cyanobacteria with different levels of ethanol production.This research has received funding from EC within the FP7 DEMA project, grant agreement no. 309086. Both S.A.C. and E.K. are supported by DEMA funding.This is the final published version. It first appeared at http://rsif.royalsocietypublishing.org/content/12/106/20150216#ack-1

Microdroplet fabrication of silver–agarose nanocomposite beads for SERS optical accumulation

Microdroplets have been used as reactors for the fabrication of agarose beads with high uniformity in shape and size, and densely loaded with silver ions, which were subsequently reduced into nanoparticles using hydrazine. The resulting nanocomposite beads not only display a high plasmonic activity, but can also trap/concentrate analytes, which can be identified by means of surface-enhanced Raman scattering (SERS) spectroscopy. The size of the beads is such that it allows the detection of a single bead under a conventional optical microscope, which is very useful to reduce the amount of material required for SERS detectio

Current and emerging techniques for diagnosis and MRD detection in AML: a comprehensive narrative review

Acute myeloid leukemia (AML) comprises a group of hematologic neoplasms characterized by abnormal differentiation and proliferation of myeloid progenitor cells. AML is associated with poor outcome due to the lack of efficient therapies and early diagnostic tools. The current gold standard diagnostic tools are based on bone marrow biopsy. These biopsies, apart from being very invasive, painful, and costly, have low sensitivity. Despite the progress uncovering the molecular pathogenesis of AML, the development of novel detection strategies is still poorly explored. This is particularly important for patients that check the criteria for complete remission after treatment, since they can relapse through the persistence of some leukemic stem cells. This condition, recently named as measurable residual disease (MRD), has severe consequences for disease progression. Hence, an early and accurate diagnosis of MRD would allow an appropriate therapy to be tailored, improving a patient’s prognosis. Many novel techniques with high potential in disease prevention and early detection are being explored. Among them, microfluidics has flourished in recent years due to its ability at processing complex samples as well as its demonstrated capacity to isolate rare cells from biological fluids. In parallel, surface-enhanced Raman scattering (SERS) spectroscopy has shown outstanding sensitivity and capability for multiplex quantitative detection of disease biomarkers. Together, these technologies can allow early and cost-effective disease detection as well as contribute to monitoring the efficiency of treatments. In this review, we aim to provide a comprehensive overview of AML disease, the conventional techniques currently used for its diagnosis, classification (recently updated in September 2022), and treatment selection, and we also aim to present how novel technologies can be applied to improve the detection and monitoring of MRD.This work was supported by European Regional Development Fund (ERDF) through COMPETE2020, under the IMPAct-L project (030782); by the Foundation for Science and Technology (FCT) projects UIDB/50026/2020 and UIDP/50026/2020; and by the project NORTE-01-0145-FEDER-000055, supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF). This project also received funding of the project Health From Portugal (C630926586-00465198), supported by Component C5–Capitalisation and Business Innovation, under the Portuguese Resilience and Recovery Plan, through the NextGenerationEU Fund. A.T. acknowledges the FCT studentship SFRH/BD/148091/2019. B.S.-M. acknowledges funding by FCT, grant number DL 57/2016

Label-Free Analysis and Sorting of Microalgae and Cyanobacteria in Microdroplets by Intrinsic Chlorophyll Fluorescence for the Identification of Fast Growing Strains.

Microalgae and cyanobacteria are promising organisms for sustainable biofuel production, but several challenges remain to make this economically viable, including identification of optimized strains with high biomass productivity. Here we report on a novel methodology for the label-free screening and sorting of cyanobacteria and microalgae in a microdroplet platform. We show for the first time that chlorophyll fluorescence can be used to measure differences in biomass between populations of picoliter microdroplets containing different species of cyanobacteria, Synechocystis PCC 6803 and Synechococcus PCC 7002, which exhibit different growth dynamics in bulk culture. The potential and robustness of this label-free screening approach is further demonstrated by the screening and sorting of cells of the green alga Chlamydomonas reinhardtii encapsulated in droplets.Author R.J.B. was supported by a Doctoral Training Grant from the Engineering and Physical Sciences Research Council (EPSRC) of the UK (Reference EP/P505445/1), and author J.J.L. was in receipt of a studentship from the Biotechnology and Biological Sciences Research Council (BBSRC) of the U.K. as part of the Cambridge BBSRC-DTP Programme (Reference BB/J014540/1). Authors S.A.-C., C.A., and A.G.S. acknowledge funding from the EC within the FP7 DEMA project, Grant Agreement No. 309086, and authors Z.Y., C.A., and A.G.S. were in receipt of funding from BBSRC sLoLa Award Reference BB/L002957/1.This is the final version of the article. It first appeared from the American Chemical Society via https://doi.org/10.1021/acs.analchem.6b0236

Isolation of acute myeloid leukemia blasts from blood using a microfluidic device

project NORTE-01-0145-FEDER-000055, supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF). This project also received funding of the project health from Portugal (C630926586-00465198), supported by Component C5 – Capitalisation and Business Innovation, under the Portuguese Resilience and Recovery Plan, through the NextGenerationEU Fund. B. S.-M. acknowledges funding by FCT, grant number DL 57/2016. The authors kindly thank Dr Oleksandr Bondarchuk for his support in the XPS analysis. This work was carried out in part through the use of the INL User Facilities. Publisher Copyright: © 2024 The Royal Society of Chemistry.Acute myeloid leukemia (AML) is the most common form of acute leukemia in adults and associated with poor prognosis. Unfortunately, most of the patients that achieve clinical complete remission after the treatment will ultimately relapse due to the persistence of minimal residual disease (MRD), that is not measurable using conventional technologies in the clinic. Microfluidics is a potential tool to improve the diagnosis by providing early detection of MRD. Herein, different designs of microfluidic devices were developed to promote lateral and vertical mixing of cells in microchannels to increase the contact area of the cells of interest with the inner surface of the device. Possible interactions between the cells and the surface were studied using fluid simulations. For the isolation of leukemic blasts, a positive selection strategy was used, targeting the cells of interest using a panel of specific biomarkers expressed in immature and aberrant blasts. Finally, once the optimisation was complete, the best conditions were used to process patient samples for downstream analysis and benchmarking, including phenotypic and genetic characterisation. The potential of these microfluidic devices to isolate and detect AML blasts may be exploited for the monitoring of AML patients at different stages of the disease.publishersversionpublishe

Development of a Plasmonic Light Management Architecture Integrated within an Interface Passivation Scheme for Ultrathin Solar Cells

InovSolarCells (PTDC/FISMAC/29696/2017) cofunded by FCT and the ERDF through COMPETE2020. Publisher Copyright: © 2024 The Authors. Solar RRL published by Wiley-VCH GmbH.In response to climate and resource challenges, the transition to a renewable and decentralized energy system is imperative. Ultrathin Cu(In,Ga)Se2 (CIGS)-based solar cells are compatible with such transition due to their low material usage and improved production throughput. Despite the benchmark efficiency of CIGS technology, ultrathin configurations face efficiency drops arising from increased rear interface recombination and incomplete light absorption. Dielectric passivation schemes address rear interface recombination, but achieving simultaneous electrical and optical gains is crucial for thinning down the absorber. Plasmonic nanoparticles emerge as a solution, enhancing light interaction through resonant scattering. In the proposed architecture, the nanoparticles are encapsulated within a dielectric rear passivation layer, combining effective passivation and light trapping. A controlled deposition and encapsulation of individualized nanoparticles is achieved by an optimized process flow using microfluidic devices and nanoimprint lithography. With the developed plasmonic and passivated architecture, a 3.7 mA cm−2 short-circuit current density and a 23 mV open-circuit voltage improvements are obtained, leading to an almost 2% increase in light-to-power conversion efficiency compared to a reference device. This work showcases the developed architecture potential to tackle the electrical and optical downfalls arising from the absorber thickness reduction, contributing to the dissemination of ultrathin technology.publishersversionpublishe

Encapsulation of Nanostructures in a Dielectric Matrix Providing Optical Enhancement in Ultrathin Solar Cells

The incorporation of nanostructures in optoelectronic devices for enhancing their optical performance is widely studied. However, several problems related to the processing complexity and the low performance of the nanostructures have hindered such actions in real-life devices. Herein, a novel way of introducing gold nanoparticles in a solar cell structure is proposed in which the nanostructures are encapsulated with a dielectric layer, shielding them from high temperatures and harsh growth processing conditions of the remaining device. Through optical simulations, an enhancement of the effective optical path length of approximately four times the nominal thickness of the absorber layer is verified with the new architecture. Furthermore, the proposed concept in a Cu(In,Ga)Se2 solar cell device is demonstrated, where the short-circuit current density is increased by 17.4%. The novel structure presented in this work is achieved by combining a bottom-up chemical approach of depositing the nanostructures with a top-down photolithographic process, which allows for an electrical contact.This work was funded in part by the Fundação para a Ciência e a Tecnologia (FCT) under Grants IF/00133/2015, PD/BD/142780/2018 and SFRH/BD/ 146776/2019. The authors also want to acknowledge the European Union’s Horizon 2020 Research and Innovation Programme through the ARCIGS-M project under Grant 720887, the Special Research Fund (BOF) of Hasselt University, the FCT through the project NovaCell (PTDC/CTM-CTM/28075/ 2017), and InovSolarCells (PTDC/FISMAC/29696/2017) co-funded by FCT and the ERDF through COMPETE2020. The authors also want to acknowledge Sandra Maya for the production of images used in this work.info:eu-repo/semantics/publishedVersio