Patterned crystal growth and heat wave generation in hydrogels

The crystallization of metastable liquid phase change materials releases stored energy as latent heat upon nucleation and may therefore provide a triggerable means of activating downstream processes that respond to changes in temperature. In this work, we describe a strategy for controlling the fast, exothermic crystallization of sodium acetate from a metastable aqueous solution into trihydrate crystals within a polyacrylamide hydrogel whose polymerization state has been patterned using photomasks. A comprehensive experimental study of crystal shapes, crystal growth front velocities and evolving thermal profiles showed that rapid growth of long needle-like crystals through unpolymerized solutions produced peak temperatures of up to 45˚C, while slower-crystallizing polymerized solutions produced polycrystalline composites and peaked at 30˚C due to lower rates of heat release relative to dissipation in these regions. This temperature difference in the propagating heat waves, which we describe using a proposed analytical model, enables the use of this strategy to selectively activate thermoresponsive processes in predefined areas.

Mussel-inspired adhesive gelatin–polyacrylamide hydrogel wound dressing loaded with tetracycline hydrochloride to enhance complete skin regeneration

Even though the global wound care market size was valued at USD 19.83 billion in 2020, it is still a challenge to develop a hydrogel-based wound dressing with a good mechanical property, adhesiveness and antibacterial property.

Remote migration of breast filler to the inguinal area: a case report

Polyacrylamide hydrogel (PAAG) is an injectable material for breast augmentation that was developed in the 1980s. It was widely used until the 2000s, but subsequently lost its popularity due to high complication rates. In this case report, we share our experience of a patient complaining of hard and asymmetric breasts who had received PAAG injections 7 years ago. Surprisingly, we found that the filler in the left breast had migrated to the left inguinal area. Although breast fillers have lost ground in recent years, we think that long-term complications of fillers, as observed in this case, will still arise in the future. Therefore, young plastic surgeons who do not have direct experience with this material should be aware of its possible complications.