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Gantz M, Neun S, Medcalf EJ, van Vliet LD, Hollfelder F. Ultrahigh-Throughput Enzyme Engineering and Discovery in In Vitro Compartments. Chem Rev 2023; 123:5571-5611. [PMID: 37126602 PMCID: PMC10176489 DOI: 10.1021/acs.chemrev.2c00910] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Indexed: 05/03/2023]
Abstract
Novel and improved biocatalysts are increasingly sourced from libraries via experimental screening. The success of such campaigns is crucially dependent on the number of candidates tested. Water-in-oil emulsion droplets can replace the classical test tube, to provide in vitro compartments as an alternative screening format, containing genotype and phenotype and enabling a readout of function. The scale-down to micrometer droplet diameters and picoliter volumes brings about a >107-fold volume reduction compared to 96-well-plate screening. Droplets made in automated microfluidic devices can be integrated into modular workflows to set up multistep screening protocols involving various detection modes to sort >107 variants a day with kHz frequencies. The repertoire of assays available for droplet screening covers all seven enzyme commission (EC) number classes, setting the stage for widespread use of droplet microfluidics in everyday biochemical experiments. We review the practicalities of adapting droplet screening for enzyme discovery and for detailed kinetic characterization. These new ways of working will not just accelerate discovery experiments currently limited by screening capacity but profoundly change the paradigms we can probe. By interfacing the results of ultrahigh-throughput droplet screening with next-generation sequencing and deep learning, strategies for directed evolution can be implemented, examined, and evaluated.
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Affiliation(s)
| | | | | | | | - Florian Hollfelder
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Rd, Cambridge CB2 1GA, U.K.
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2
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Yonet-Tanyeri N, Amer M, Balmert SC, Korkmaz E, Falo LD, Little SR. Microfluidic Systems For Manufacturing of Microparticle-Based Drug-Delivery Systems: Design, Construction, and Operation. ACS Biomater Sci Eng 2022; 8:2864-2877. [PMID: 35674145 PMCID: PMC10368402 DOI: 10.1021/acsbiomaterials.2c00066] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Particles synthesized from biodegradable polymers hold great potential as controlled drug delivery systems. Continuous flow platforms based on microfluidics offer attractive advantages over conventional batch-emulsification techniques for the scalable fabrication of drug-loaded particles with controlled physicochemical properties. However, widespread utilization of microfluidic technologies for the manufacturing of drug-loaded particles has been hindered largely by the lack of practical guidelines toward cost-effective development and reliable operation of microfluidic systems. Here, we present a framework for rational design and construction of microfluidic systems using commercially available components for high-throughput production of uniform biodegradable particles encapsulating drugs. We also demonstrate successful implementation of this framework to devise a robust microfluidic system that is capable of producing drug-carrying particles with desired characteristics. The guidelines provided in this study will likely help broaden the applicability of microfluidic technologies for the synthesis of high-quality, drug-loaded biodegradable particles.
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Affiliation(s)
- Nihan Yonet-Tanyeri
- Department of Chemical Engineering, University of Pittsburgh, 3700 O'Hara Street, 940 Benedum Hall, Pittsburgh, Pennsylvania 15261, United States
| | - Maher Amer
- Department of Dermatology, University of Pittsburgh School of Medicine, 200 Lothrop Street, W1150 Biomedical Science Tower, Pittsburgh, Pennsylvania 15213, United States
| | - Stephen C Balmert
- Department of Dermatology, University of Pittsburgh School of Medicine, 200 Lothrop Street, W1150 Biomedical Science Tower, Pittsburgh, Pennsylvania 15213, United States
| | - Emrullah Korkmaz
- Department of Dermatology, University of Pittsburgh School of Medicine, 200 Lothrop Street, W1150 Biomedical Science Tower, Pittsburgh, Pennsylvania 15213, United States.,Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Louis D Falo
- Department of Dermatology, University of Pittsburgh School of Medicine, 200 Lothrop Street, W1150 Biomedical Science Tower, Pittsburgh, Pennsylvania 15213, United States.,Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States.,Clinical and Translational Science Institute, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, United States.,The McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15219, United States
| | - Steven R Little
- Department of Chemical Engineering, University of Pittsburgh, 3700 O'Hara Street, 940 Benedum Hall, Pittsburgh, Pennsylvania 15261, United States.,Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States.,The McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15219, United States.,Department of Immunology, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, United States.,Department of Ophthalmology, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, United States.,Department of Pharmaceutical Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
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Formation and Elimination of Satellite Droplets during Monodisperse Droplet Generation by Using Piezoelectric Method. MICROMACHINES 2021; 12:mi12080921. [PMID: 34442543 PMCID: PMC8398856 DOI: 10.3390/mi12080921] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Revised: 07/25/2021] [Accepted: 07/28/2021] [Indexed: 01/22/2023]
Abstract
One of the key questions in the generation of monodisperse droplets is how to eliminate satellite droplets. This paper investigates the formation and elimination of satellite droplets during the generation of monodisperse deionized water droplets based on a piezoelectric method. We estimated the effects of two crucial parameters—the pulse frequency for driving the piezoelectric transducer (PZT) tube and the volume flow rate of the pumping liquid—on the generation of monodisperse droplets of the expected size. It was found that by adjusting the pulse frequency to harmonize with the volume flow rate, the satellite droplets can be eliminated through their coalescence with the subsequent mother droplets. An increase in the tuning pulse frequency led to a decrease in the size of the monodisperse droplets generated. Among three optimum conditions (OCs) (OC1: 20 mL/h, 20 kHz; OC2: 30 mL/h, 30 kHz; and OC3: 40 mL/h, 40 kHz), the sizes of the generated monodisperse deionized water droplets followed a bimodal distribution in OC1 and OC2, whereas they followed a Gaussian distribution in OC3. The average diameters were 87.8 μm (OC1), 85.9 μm (OC2), and 84.8 μm (OC3), which were 8.46%, 6.14%, and 4.69% greater than the theoretical one (81.0 μm), respectively. This monodisperse droplet generation technology is a promising step in the production of monodisperse aerosols for engineering applications.
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