ABSTRACT
Over the years, synthetic hydrogels have proven remarkably useful as cell culture matrixes to elucidate the role of the extracellular matrix (ECM) on cell behavior. Yet, their lack of interconnected macropores undermines the widespread use of hydrogels in biomedical applications. To overcome this limitation, cryogels, a class of macroporous hydrogels, are rapidly emerging. Here, we introduce a new, highly elastic, and tunable synthetic cryogel, based on poly(isocyanopeptides) (PIC). Introduction of methacrylate groups on PIC facilitated cryopolymerization through free-radical polymerization and afforded cryogels with an interconnected macroporous structure. We investigated which cryogelation parameters can be used to tune the architectural and mechanical properties of the PIC cryogels by systematically altering cryopolymerization temperature, polymer concentration, and polymer molecular weight. We show that for decreasing cryopolymerization temperatures, there is a correlation between cryogel pore size and stiffness. More importantly, we demonstrate that by simply varying the polymer concentration, we can selectively tune the compressive strength of PIC cryogels without affecting their architecture. This unique feature is highly useful for biomedical applications, as it facilitates decoupling of stiffness from other variables such as pore size. As such, PIC cryogels provide an interesting new biomaterial for scientists to unravel the role of the ECM in cellular functions.
Subject(s)
Cryogels , Cryogels/chemistry , Porosity , Peptides/chemistry , Hydrogels/chemistry , Hydrogels/chemical synthesis , Biocompatible Materials/chemistry , Polymerization , Polymers/chemistry , Compressive Strength , Extracellular Matrix/chemistryABSTRACT
The effects on adherence and depressive symptoms of a community pharmacy-based coaching program, including a take-home videotape, were evaluated in a randomized controlled trial in the Netherlands. A total of 147 depressed primary care patients who had a new antidepressant prescription were included in the study. Adherence was measured with an electronic pill container and was also derived from pharmacy medication records; the latter method was associated with an overestimation of adherence of only 5 percent. Intention-to-treat analyses showed no intervention effect on adherence (73 percent compared with 76 percent), whereas analyses of patients who received the intervention (per protocol) showed improved adherence (73 percent compared with 90 percent). Neither analysis showed effects on depressive symptoms.
