2019 PST Awardees

The Outstanding Achievement Award

The Photopolymer Science and Technology Award No.191100

Robert D.  Allen

IBM Research, Almaden

The Photopolymer Science and Technology Award No. 191100, the Outstanding Achievement Award 2019, was presented to Dr. Robert D. Allen (IBM Research, Almaden) for his outstanding achievements in photopolymer science and technology, “Pioneering semiconductor patterning technology using water immersion ArF lithography with the originally designed photoresist”.

The Best Paper Award 2019

The Photopolymer Science and Technology Award 192100

Hiroaki Takehara, Yukihiro Kanda, and Takanori Ichiki

The University of Tokyo, Japan

The Photopolymer Science and Technology Award No. 182100, the Best Paper Award 2018, was presented to Hiroaki Takehara, Yukihiro Kanda, and Takanori Ichiki (Department of Materials Engineering, School of Engineering, The University of Tokyo) for their outstanding contribution published in Journal of Photopolymer Science and Technology, 31, (2018) 59–63, entitled “Microfluidic Model for Optical Detection of Nanoparticles in Whole Blood”.
 

     Microfabrication technology has played an important role in the advancement of bio-analysis methods. Microfluidic device technologies started from devices for molecular analysis in early 1990s [1,2], and Prof. Ichiki contributed to drive its advancement in early stage by applying microfabrication technology for LSI devices [3-8]. Furthermore, remarkable progress in polymer technology has also played a pivotal role in the development of biomedical devices and drug delivery systems because of their biocompatibility and functionality [9-12].      In the technological advancement as mentioned above, the combined use of microfabrication technology and functional polymer materials can be a promising approach to bestow effective measurement methods in biological environment (in situ) and even inside the living body (in vivo). In situ and in vivo measurements of molecules, cells, biological tissues, and living animals, are highly attractive for both powerful tools to obtain new insights in fundamental biological studies and medical applications to provide information in diagnostics [13,14].

    Dr. Takehara, Prof. Ichiki and their collaborative researchers have been proposed novel device technology focusing on “in vivo” and “in situ” measurements towards biomedical applications. Recently, they developed in vivo measurement method of living mouse brain using microfluidic device platform (named as lab-onbrain) [15-17], and implantable semiconductor devices [18,19]. They also developed in situ monitoring method of temperature of liquids [20], cellular oxygen metabolism [21], and cellular response to cytokines [22], based on the materials technology and microfabrication technology. 

    In this article, they investigated optical measurement methods of therapeutic polymer nanoparticles in the blood stream. Light has shown great potential as a safe energy source for sensing, owing to unique photon energy range of light around 0.53 eV that allows effective yet safe interactions with polymer materials and biological tissues [23]. The core challenge in the optical measurement of polymer nanoparticles in blood is absorption of light by complex interferents. The absorbed photon energy can be converted into heat by the photothermal effect and re-emitted through luminescence as autofluorescence. Thus, in the present study, they studied photothermal effect and the autofluorescence by using a microfluidic model. The photothermal effect was evaluated by observing temperature increases in whole blood with laser-induced fluorescence spectroscopy. The detection limit of fluorescent nanoparticles was elucidated in the presence of autofluorescence as the background noise in the whole blood.

    As described above, the authors have investigated the role of the photothermal effect and autofluorescence in the measurement of fluorescence from polymer nanoparticles in the blood by using a specially designed experimental model based on microfluidic chip technology and fluorescence microspectroscopy. These results provide valuable insights to pave the way for the development of optical sensing methods for monitoring biological molecules or therapeutic drugs inside the body. 

     These important research results were presented at the International Conference of Photopolymer Science and Technology in 2018 and the paper was published in the Journal of Photopolymer Science and Technology. These contributions give the advancement of photopolymer science and technology in the field of biomedical engineering. 

References

The Best Paper Award 2019

The Photopolymer Science and Technology Award 192200

Satoshi Takei, Makoto Hanabata, Kento Mizui, Kazuho Kurematsu, and Shinya Nakajima 

Toyama Prefectural University, Japan

The Photopolymer Science and Technology Award No. 182200, the Best Paper Award 2018, was presented to Satoshi Takei, Makoto Hanabata, Kento Mizui, Kazuho Kurematsu, and Shinya Nakajima (Departments of Mechanical Systems Engineering and Pharmaceutical Engineering, Toyama Prefectural University) for their outstanding contribution published in Journal of Photopolymer Science and Technology, 31, (2018) 289–294, entitled “Reduction of Defect for Imprinted UV Curable Resin including Volatile Solvents using Gas Permeable Mold Derived from Cellulose”.

     The mainstream of microfabrication technology is a photolithography [1,2]. Photolithography is a suitable process that can transfer geometric patterns to a film or substrate. However, due to the increasing cost to achieve high resolution, it reaches to the limitations. In this situation, imprint lithography (IL) has drawn much attention because of its high productivity and low cost. The IL is a processing method [3,4]. It was reported that it is possible in transcription of 10 nm [5]. This technique has a high resolution, high throughput, high aspect ratio patterning, cost reduction, and large area patterning [6-10]. The applicability of IL has wide varieties of biosensor, optical materials, and compact discs. [11-13]. It is promising as the next generation microfabrication technologies. A gas impermeable quartz mold used in conventional processes often causes air trapping and out gas accumulation between the mold and the transfer material. To solve the air trapping problem, the use of pentafluoropropane was suggested [14].  In previous studies, we reported a gas permeable mold derived from cellulose reduces the void caused by the outgas from acrylic material including acetone [15-17]. The pattern failures caused by the air trapping and the outgassing between the mold and the UV curing liquid material were removed because these gasses easily passed outside through the gas permeable mold.

     This paper reports a new family of imprint mold that the authors have recently developed. Mass productivity of the gas permeable mold from quartz master mold was confirmed by replicating a large amount of gas permeable mold. Defects in line and space patterns of the UV-cross-linkable materials including 10 wt% of acetone, 10 wt% of 1-methoxy2-propyl acetate and 10 wt% of cyclopentane as volatile solvents were greatly eliminated by using the developed gas permeable mold derived from biomass.  

     These results were also presented at the International Conference of Photopolymer Science and Technology in 2018. The work on the imprint lithography has recently greatly progressed, providing novel structures of gas permeable molds derived from biomass. This approach is expected to expand the utility of non-liquid materials which need solvents that are currently not suitable for imprint lithography. The progress will be presented at the International Conference of Photopolymer Science and Technology in 2018 [17]. 

     The results presented in this paper provide a new useful family of imprint molds with unprecedented advantages, and hence deserves the Photopolymer Science and Technology Award.