The 8th HIC/RPC Bioseparation Conference was held on March 3–7, 2013 at the Westin Savannah Harbor Resort in Savannah, Georgia, USA. The conference series, which alternates between Europe and the USA, provides a unique forum for in-depth discussion of downstream processing. Following its tagline “Advancements, Applications, and Theory in Downstream Processing” the conference traditionally focuses on bioprocess applications and on fundamental research in hydrophobically influenced modes of chromatography. In the course of time, the emphasis of the conference has shifted towards hydrophobic interactions (HIC), and in recent years towards mixed-mode chromatography. For this year's conference, the scientific committee, headed by Steven M. Cramer (Rensselaer Polytechnic Institute (RPI), USA) composed a stimulating program, balanced between basic research and industrial applications.
The program started with a keynote lecture by Abraham Lenhoff (University of Delaware, USA), who reflected on the “Role of Water in Protein Interactions”. Abraham Lenhoff showed that water plays diverse roles not only in the hydrophobic modes of chromatography but also for protein interactions in general. Shekhar Garde (RPI) continued along this theme with a keynote lecture on “Water, Proteins and Interfaces: A New Molecular Perspective.” Shekhar Garde's inspiring presentation spanned a wide range of topics, from the politics and philosophy of water to the key features of water and water-mediated interactions. From a molecular level perspective, he discussed the different ways water molecules organize themselves near hydrophilic, hydrophobic and ionic solutes, and near interfaces that include a combination of these characteristics, such as proteins. The third keynote lecture was given by Milton Hearn (Monash University, Australia) and focused on water and the sudden interest in its use in reversed phase, mixed-mode, and hydrophobic interaction bioseparations. Milton Hearn highlighted some of the work done at Monash University together with theoretical analysis on the function of water in bioseparations at a molecular level.
The “water theme” was finally wrapped up in a round table discussion – “How to Use Fundamental Understandings of Water, Proteins and Interfaces to Develop New Bioprocesses and Separations Materials.” Shekhar Garde emphasized the importance of molecular modeling to better understand the mechanisms of chromatography. Modes such as ionic exchange chromatography may already be fully understood but all panel members agreed that more efforts should be made for HIC and multimodal chromatography modeling due to the more complex interactions. Egbert Müller (Tosoh Bioscience, Germany) expressed the industry's interest for the latest development in this fundamental knowledge, which could be a key technique for the development of new chromatographic media in the future.
The basic research session offered a range of approaches on the fundamental understanding of hydrophobic interaction and mixed-mode chromatography. While Steven Cramer focused on protein-ligand interactions for multimodal cation exchangers, Christian Frech (University of Applied Science Mannheim, Germany) analyzed binding mechanisms on multimodal anion exchange resins. Rupert Tscheliessnig (Austrian Centre of Industrial Biotechnology) gave a presentation on in situ imaging on the nanoscale for the analysis of proteins and their conformation in solution. Elisabeth Hallgren (GE Healthcare, Sweden) presented a follow-up study to her 2011 HIC/RPC presentation on Atomic Force Microscopy (AFM) using a single HIC resin particle as a colloidal probe to measure its interaction with proteins in solution. Shuichi Yamamoto (Yamaguchi University, Japan) gave a presentation on salt-tolerant chromatography and how it works, covering binding sites, peak salt concentrations and the equilibrium coefficient of proteins in salt-tolerant chromatography.
Quality-by-Design and modeling were other key topics of the Conference. Marcus Degerman (Lund University, Sweden) gave a presentation on mechanistic modeling for HIC and RPC purifications and was a good example of how a talk on modeling can indeed be very entertaining. By mechanistic modeling, experimental resources were focused on generating a deeper process understanding and creating a modeling toolbox at the same time. Marcel Ottens (Delft University, The Netherlands) also presented how high-throughput screening approaches can be made more comprehensive and efficient by including mechanistic modelling, resulting in the so-called in silico process development. This scheme allows for accelerated resin screening and a more directed process development approach, which was illustrated by several case studies.
The industrial case studies and the practical applications of HIC and mixed-mode chromatography presented this year covered a broad range of target molecules such as monoclonal antibodies, bispecific antibodies, viruses, virus-like particles, etc. Jie Chen (DYAX Corporation, USA) talked about the differences between three commercially available, multimodal cation exchange media with regard to their separation mechanisms and their performance for various process steps, such as the capturing of a monoclonal antibody and of a recombinant protein expressed in Escherichia coli. Her presentation indicated that multimodal chromatography resins may be an excellent choice for a capture step while affinity chromatography is not a viable option. Kerry White (Genzyme, USA) discussed the use of lysozyme retention on a HIC resin as a molecular model to predict resin performance at large scale for the purification of a complex glycoprotein. Yan Chen (VaxInnate Corp., USA) presented the process development of a HIC polishing step for a protein vaccine candidate.
The last session of the Conference was dedicated to the presentation of novel stationary phases. This year, all developments were in some way related to multimodal resins, underlining the growing interest in this mode of chromatography. Egbert Müller presented the use of a tryptophan-based multimodal cation exchange resin for an aggregate removal step and for the purification of antibody derived molecules such as F(ab')2 fragments. Xuemei He (Bio-Rad Laboratories, USA) showed the potential of mixed-mode chromatography for the purification of non-antibody proteins that lack an affinity capture option and provided a guideline on how to start process development for their new hydrophobic cation exchange media. Koji Nakamura (Tosoh Corporation, Japan) presented the characterization, elution conditions and potential applications of a new salt-tolerant anion exchange resin. Kristina Nilsson-Välimaa (GE Healthcare, Sweden) completed this session with a talk on the use of a smaller version of an established multimodal anion exchange media for mAb polishing.
For the first time, poster presenters were offered the opportunity to give a brief oral overview of their work in front of the assembled attendees. Seven of the poster presenters took this opportunity to discuss their work and it is hoped that this year's poster presenters will return as speakers and presenters to the next HIC-RPC conference and many other conferences to come. In keeping with tradition, the conference offered not only a high- class scientific program but also various opportunities to network with colleagues. The 9th HIC/RPC Bioseparation Conference will take place in March, 2015 on the beautiful island of Malta.
The authors declare no conflict of interest.
Regina Roemling, Tosoh Bioscience, Stuttgart, Germany
Alois Jungbauer, University of Nature Resources and Life Sciences, Vienna, Austria
Conference website: www.hic-rpc.org