Polyelectrolyte (PE) hydrogels are typical soft materials with extremely high swelling capacity due to the high osmotic pressure of the dissociated counterions. [1] For example,
Hydrogel-based soft electronics (HSE) is promising as implantable devices due to the similarity of hydrogel substrates to biologic tissues. Most existing HSE devices are based on conducting hydrogels that usually have weak mechanical properties, low conductivity, and poor patternability. Reported here is an HSE with good mechanical performance, high sensitivity, and versatile functions by stencil printing of liquid metal on a tough hydrogel, facilitating integration of multiple sensing units. Self-shaping ability is imparted to the HSE by creating gradient structure in the hydrogel substrate. The resultant HSE actively deforms into 3D configurations with zero or nonzero Gaussian curvature to fix on objects or organs with sophisticated geometries and maintains the sensing functions. The versatilities and potential applications of this HSE are demonstrated by monitoring motions of a rice field eel and beatings of a rabbit heart. Such HSE based on morphing substrate should pave the way for implantable electronics with better fixation and interfacial contact with the organs. The concept of morphing hydrogel devices can be extended to other soft electronics with responsive polymer films or elastomers as the substrates.
Designing tough biopolymer-based hydrogels as structural biomaterials has both scientific and practical significances. We report a facile approach to prepare polysaccharide-based hydrogel films with remarkable mechanical performances and antiadhesion property. The hydrogel films with a thickness of 40-60 μm were prepared by mixing aqueous solutions of κ-carrageenan (κ-CG) and protonated chitosan (CS), evaporating the solvent, and then swelling the casted film in water to achieve the equilibrium state. The obtained κ-CG/CS gel films with a water content of 48-88 wt % possessed excellent mechanical properties with a breaking stress of 2-6.7 MPa and a breaking strain of 80-120%, superior to the most existing biopolymer-based hydrogels. The extraordinary mechanical properties of gel films obtained over a wide range of mass ratio of κ-CG to CS should be rooted in the synergistic effect of ionic and hydrogen bonds between the κ-CG and CS molecules. In addition, the tough gel films showed good self-recovery ability, biocompatibility, and cell antiadhesion property, making them promising as an artificial dura mater and diaphragm materials in the surgery. The design principle by incorporating multiple noncovalent bonds to toughen the biopolymer-based hydrogels should be applicable to other systems toward structural biomaterials with versatile properties.
The overall moderate evidence from the RCTs confirmed the significantly short-term and middle-term efficacy of BPs on periprosthetic bone loss after joint arthroplasty. To obtain a better efficacy, the second and the third generation of BPs may be the choice.
The aim of this study was to perform a head-to-head comparison of efficacy and safety profile between 60 mg denosumab (Den) subcutaneously (SC) per 6 months (Q6M) and 70 mg alendronate (Aln) orally per week (QW) for postmenopausal women with low bone mineral density. We searched electronic databases comparing efficacy and safety of Den SC Q6M and Aln QW in postmenopausal women. The primary outcomes of efficacy evaluation in included trials were incidence of clinical fracture in both groups and bone mineral density (BMD) at different skeletal sites. And adverse events (AEs), including incidence of neoplasms and infections, were considered as secondary outcomes. Following the instructions of 'Cochrane Handbook for systematic Reviews of Interventions 5.0.2', we identified eligible studies, evaluated the methodological quality and abstracted relevant data. Four heterogeneous randomised controlled trials (RCTs) involving 1942 women were identified. The results of review showed low evidence quality that supported the hypothesis the denosumab vs. alendronate could reduce risk of fracture [OR (95% CI) 1.42 (0.84 to 2.40), 11 more women per 1000 (from 4 fewer to 36 more), p = 0.19] but the moderate to high quality evidence suggesting treatment with 60 mg Den SC Q6M was more effective for postmenopausal women in increasing BMD [at distal radius (DR), total hip (TH), lumbar spine (LS), and femoral neck (FN)]. Hazards of neoplasms [OR (95% CI) 1.10 (0.65 to 1.86), 3 more per 1000 (from 10 fewer to 24 more), p = 0.62] or infections [OR (95% CI) 0.95 (0.79 to 1.15), 12 fewer per 1000 (from 53 fewer to 33 more,), p = 0.62] were appeared to be similar.Our review suggested within 1 year 60 mg Den SC Q6M treatment was more effective in increasing bone mass but could not reduce the fracture risk to a greater extent than 70 mg Aln QW therapy. Also the Den SC Q6M therapy did not increase the risks of neoplasms and infections compared with Aln QW.
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