MSGID: 1:317/3 63fed4f3   
   PID: hpt/lnx 1.9.0-cur 2019-01-08   
   TID: hpt/lnx 1.9.0-cur 2019-01-08   
    New purification method could make protein drugs cheaper    
      
     Date:   
         February 28, 2023   
     Source:   
         Massachusetts Institute of Technology   
     Summary:   
         Engineers devised a way to purify protein drugs during   
         manufacturing.   
      
         Their approach, which uses nanoparticles to rapidly crystallize   
         proteins, could help make protein drugs more affordable and   
         accessible, especially in developing countries.   
      
      
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   FULL STORY   
   ==========================================================================   
   One of the most expensive steps in manufacturing protein drugs such as   
   antibodies or insulin is the purification step: isolating the protein   
   from the bioreactor used to produce it. This step can account for up to   
   half of the total cost of manufacturing a protein.   
      
      
   ==========================================================================   
   In an effort to help reduce those costs, MIT engineers have devised   
   a new way to perform this kind of purification. Their approach, which   
   uses specialized nanoparticles to rapidly crystallize proteins, could   
   help to make protein drugs more affordable and accessible, especially   
   in developing countries.   
      
   "This work uses bioconjugate-functionalized nanoparticles to act as   
   templates for enhancing protein crystal formation at low concentrations,"   
   says Kripa Varanasi, a professor of mechanical engineering at MIT and   
   the senior author of the new study. "The goal is to reduce the cost so   
   that this kind of drug manufacturing becomes affordable in the developing   
   world."  The researchers demonstrated that their approach can be used to   
   crystallize lysozyme (an antimicrobial enzyme) and insulin. They believe   
   it could also be applied to many other useful proteins, including antibody   
   drugs and vaccines.   
      
   MIT graduate student Caroline McCue is the lead author of the   
   study, which appears today in the journal ACS Applied Materials and   
   Interfaces. Henri-Louis Girard PhD '20 is also an author of the paper.   
      
   Protein purification Antibodies and other protein drugs are part of a   
   growing class of drugs known as biologics, which also include molecules   
   such as DNA and RNA, as well as cell-based therapies. Most protein drugs   
   are produced by living cells such as yeast in large bioreactors.   
      
   Once these proteins are generated, they have to be isolated   
   from the reactor, which is usually done through a process called   
   chromatography. Chromatography, which separates proteins based on their   
   size, requires specialized materials that make the process very expensive.   
      
   Varanasi and his colleagues decided to try a different approach, based on   
   protein crystallization. Researchers often crystallize proteins to study   
   their structures, but the process is considered too slow for industrial   
   use and doesn't work well at low concentrations of protein. To overcome   
   those obstacles, Varanasi's lab set out to use nanoscale structures to   
   speed up the crystallization.   
      
   In previous work, the lab has used nanoscale features to create   
   materials that repel water or to modify interfaces for injecting highly   
   viscous biologic drugs. In this case, the researchers wanted to adapt   
   nanoparticles so that they could locally increase the concentration of   
   protein at the surface and also provide a template that would allow the   
   proteins to align correctly and form crystals.   
      
   To create the surface they needed, the researchers coated gold   
   nanoparticles with molecules called bioconjugates -- materials that can   
   help form links between other molecules. For this study, the researchers   
   used bioconjugates called maleimide and NHS, which are commonly used for   
   tagging proteins for study or attaching protein drugs to drug-delivering   
   nanoparticles.   
      
   When solutions of proteins are exposed to these coated   
   nanoparticles, the proteins accumulate at the surface and bind to the   
   bioconjugates. Furthermore, the bioconjugates compel the proteins to   
   align themselves with a specific orientation, creating a scaffold for   
   additional proteins to come along and join the crystal.   
      
   The researchers demonstrated their approach with lysozyme, an enzyme   
   whose crystallization properties have been well studied, and insulin. They   
   say it could also be applied to many other proteins.   
      
   "This is a general approach that could be scaled to other systems as   
   well. If you know the protein structure that you're trying to crystallize,   
   you can then add the right bioconjugates that will force this process   
   to happen," Varanasi says.   
      
   Rapid crystallization In their studies with lysozyme and insulin, the   
   researchers found that crystallization occurred much faster when the   
   proteins were exposed to the bioconjugate-coated nanoparticles, compared   
   to bare nanoparticles or no nanoparticles. With the coated particles,   
   the researchers saw a sevenfold reduction in the induction time -- how   
   long it takes for crystals to begin forming -- and a threefold increase in   
   the nucleation rate, which is how quickly the crystals grow once started.   
      
   "Even at low protein concentrations, we see a lot more crystals forming   
   with these bioconjugate-functionalized nanoparticles," McCue says. "The   
   functionalized nanoparticles reduce the induction time so much because   
   these bioconjugates are providing a specific site for the proteins   
   to bind. And because the proteins are aligned, they can form a crystal   
   faster."  In addition, the team used machine learning to analyze thousands   
   of images of crystals. "Protein crystallization is a stochastic process,   
   so we needed to have a huge dataset to be able to really measure whether   
   our approach was improving the induction time and nucleation rate of   
   crystallization. With so many images to process, machine learning is the   
   best way to be able to determine when crystals are forming in each image   
   without having to go through and manually count each one," McCue says.   
      
   This project is part of a Bill and Melinda Gates Foundation effort to make   
   biologic drugs, such as prophylactic antibodies that have been shown to   
   prevent malaria in clinical trials, more widely available in developing   
   nationsThe MIT team is now working on scaling up the process so that   
   it could be used in an industrial bioreactor, and demonstrating that it   
   can work with monoclonal antibodies, vaccines, and other useful proteins.   
      
   "If we can make it easier to manufacture these proteins anywhere, then   
   everyone in the world can benefit," Varanasi says. "We are not saying   
   that this is going to be solved tomorrow because of us, but this is a   
   small step that can contribute to that mission."  In addition to the   
   Gates Foundation, the research was partly funded by a National Science   
   Foundation Graduate Research Fellowship.   
      
       * RELATED_TOPICS   
             o Health_&_Medicine   
                   # Human_Biology # Prostate_Cancer # Pharmacology #   
                   HIV_and_AIDS   
             o Matter_&_Energy   
                   # Biochemistry # Organic_Chemistry # Nature_of_Water #   
                   Nanotechnology   
       * RELATED_TERMS   
             o Soy_protein o Analgesic o Collagen o Protein   
             o Protein_structure o Protein_microarray o   
             Denaturation_(biochemistry) o Antiretroviral_drug   
      
   ==========================================================================   
   Story Source: Materials provided by   
   Massachusetts_Institute_of_Technology. Original written by Anne   
   Trafton. Note: Content may be edited for style and length.   
      
      
   ==========================================================================   
   Journal Reference:   
      1. Caroline McCue, Henri-Louis Girard, Kripa K. Varanasi. Enhancing   
      Protein   
         Crystal Nucleation Using In Situ Templating on Bioconjugate-   
         Functionalized Nanoparticles and Machine Learning. ACS Applied   
         Materials & Interfaces, 2023; DOI: 10.1021/acsami.2c17208   
   ==========================================================================   
      
   Link to news story:   
   https://www.sciencedaily.com/releases/2023/02/230228154519.htm   
      
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