Filters

2021 - 20222

More filters

2022 - 20232
Reset filters

Settings

DDC: 540 × Subject: Materials properties ×

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Controlling optical trapping of metal–dielectric hybrid nanoparticles under ultrafast pulsed excitation: a theoretical investigation
    (Cambridge : Royal Society of Chemistry, 2021) Devi, Anita; Nair, Shruthi S.; Yadav, Sumit; De, Arijit K.
    Crucial to effective optical trapping is the ability to precisely control the nature of force/potential to be attractive or repulsive. The nature of particles being trapped is as important as the role of laser parameters in determining the stability of the optical trap. In this context, hybrid particles comprising of both dielectric and metallic materials offer a wide range of new possibilities due to their tunable optical properties. On the other hand, femtosecond pulsed excitation is shown to provide additional advantages in tuning of trap stiffness through harnessing optical and thermal nonlinearity. Here we demonstrate that (metal/dielectric hybrid) core/shell type and hollow-core type nanoparticles experience more force than conventional core-type nanoparticles under both continuous-wave and, in particular, ultrafast pulsed excitation. Thus, for the first time, we show how tuning both materials properties as well as the nature of excitation can impart unprecedented control over nanoscale optical trapping and manipulation leading to a wide range of applications.
  • Thumbnail Image
    Item
    Redox-triggerable firefly luciferin-bioinspired hydrogels as injectable and cell-encapsulating matrices
    (Cambridge : RSC Publ., 2022) Jin, Minye; Gläser, Alisa; Paez, Julieta I.
    Stimuli-responsive hydrogels are smart materials that respond to variations caused by external stimuli and that are currently exploited for biomedical applications such as biosensing, drug delivery and tissue engineering. The development of stimuli-responsive hydrogels with defined user control is relevant to realize materials with advanced properties. Recently, our group reported firefly luciferin-inspired hydrogel matrices for 3D cell culture. This platform exhibited advantages like rapid gelation rate and tunability of mechanical and biological properties. However, this first molecular design did not allow fine control of the gelation onset, which restricts application as a cell-encapsulating matrice with injectable and processable properties. In this article, we endow the firefly luciferin-inspired hydrogels with redox-triggering capability, to overcome the limitations of the previous system and to widen its application range. We achieve this goal by introducing protected macromers as hydrogel polymeric precursors that can be activated in the presence of a mild reductant, to trigger gel formation in situ with a high degree of control. We demonstrate that the regulation of molecular parameters (e.g., structure of the protecting group, reductant type) and environmental parameters (e.g., pH, temperature) of the deprotection reaction can be exploited to modulate materials properties. This redox-triggerable system enables precise control over gelation onset and kinetics, thus facilitating its utilization as an injectable hydrogel without negatively impacting its cytocompatibility. Our findings expand the current toolkit of chemically-based stimuli-responsive hydrogels.