To clarify the motor function of the infant tongue during sucking, we developed an artificial nipple that contained multiple small built‐in force sensors integrated with a PC‐based system which is capable of measuring tongue–artificial nipple contact pressures in real time. The force sensor is a cantilever structure with a small, thin stainless steel beam where an all‐purpose foil strain gauge is attached to the surface of the beam. An artificial nipple made of an elastomer containing these sensors is connected through an amplifier and an A/D converter to a PC via a USB port. Using this system, measurements were taken in three infants whose oral feeding was well established and in one infant of low birth weight. The results from each force sensor showed a pressure waveform of a nearly simple harmonic motion that indicated a peristalsis‐like movement of the tongue; the sucking frequency was found to be about two times per second. In addition, in the low‐birth‐weight infant, the pressure changed as the infant grew. © 2012 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

In order to clarify the dynamic mechanisms involved in sucking by infants, we developed an artificial nipple with built-in force sensors and have measured the contact force between the tongue and the artificial nipple in infants including healthy, premature and low birth weight. In this study, we measured the force applied by the tongue on the artificial nipple in 10 healthy infants and in 10 infants who were also tube-fed and investigated the differences in dynamic actions between the two groups to extract factors involved in satisfactory sucking. The results showed that differences in the maximum force applied and in the time to reach the maximum force were found between infants with and without established oral feeding. For an infant to suck satisfactorily, 1) the time for the force to propagate from the tongue tip to the tongue root needs to constitute at least 8 % of the sucking period and 2) the force applied at the tongue tip needs to be at least 50% of the force at the tongue root.

Infants are known to suckle and ingest breast milk by wrapping the tongue around a nipple, writhing the tongue, and pressing the nipple. However, the dynamic mechanisms of tongue movement are still obscure, and factors related to sucking difficulties of infants are not well understood. We developed an artificial nipple installed with small cantilever-type sensors and directly measured the force applied on the nipple by the tongue. Small force sensors were arranged within the artificial nipple in a two-dimensional matrix of 3 × 2 to measure the force at 6 points. Subjects were 20 healthy infants (Group A) and 5 infants who had difficulty sucking (Group B). The latter could not breastfeed well and were fed from bottles or tubes. Informed consent was provided by the parents or guardians. The measured maximum force at the tip of the nipple was 1.4 ± 0.4 N and 1.2 ± 0.3 N (mean ± SD) in Groups A and B, respectively. At the base of the nipple, the maximum force recorded was 0.8 ± 0.5 N and 0.3 ± 0.3 N (mean ± SD), respectively, showing a statistically significant difference (p<0.05). The sucking period was 0.6 ± 0.1 s (mean ± SD) in both groups. The difference in time necessary to reach the maximum forces between the sensors at the tip and base was 39.7 ± 28.8 ms (mean ± SD) and 37.2 ± 75.9 ms in Groups A and B, respectively.

Dopamine and its derivatives have been discovered as biomimetic adhesive motifs for various applications, but their affordability has been an obstacle to their practical realization. To address both high performance and productivity, we propose hydroxytyrosol as a nature-based adhesive motif. The productivity of hydroxytyrosol was overcome by the biosynthesis of hydroxytyrosol using glucose as the starting material. Because hydroxytyrosol is not easily autoxidized, hydroxytyrosol can be introduced into alkyl methacrylate through an unprotected one-pot transesterification reaction. The resulting adhesive copolymers with hydroxytyrosol as a side chain show adhesive properties comparable to those of the corresponding dopamine-containing polymers.

No abstract