Synthetic Cartilage

April 28, 2019

Biomacromolecules. 2019 Apr 22.

doi: 10.1021/acs.biomac.9b00237. [Epub ahead of print]
Double Network Hydrogels that Mimic the Modulus, Strength and Lubricity of Cartilage.
Means AK, Shrode CS, Whitney LV, Ehrhardt DA, Grunlan MA.
Abstract

The development of a hydrogel-based synthetic cartilage has the potential to overcome many limitations of current chondral defect treatments. Many efforts have attempted to replicate the unique characteristics of cartilage in hydrogels, but none simultaneously achieved high modulus, strength and toughness while maintaining the necessary hydration required for lubricity. Herein, double network (DN) hydrogels, composed of a poly(2-acrylamido-2-methylpropane sulfonic acid) (PAMPS) 1st network and a poly(N-isopropyl-acrylamide-co-acrylamide) [P(NIPAAm-co-AAm)] 2nd network, are evaluated as a potential off-the-shelf material for cartilage replacement. While predominantly used for its thermosensitivity, PNIPAAm is employed to achieve superior mechanical properties and its thermal transition temperature tuned above the physiological range. These PNIPAAm-based DNs demonstrate a 50-fold increase in compressive strength (~25 MPa, similar to cartilage) compared to traditional single network hydrogels while also achieving a cartilage-like modulus (~1 MPa) and hydration (~80%). By directly comparing to healthy cartilage (porcine), these hydrogels are confirmed not only to parallel the strength, modulus and hydration of native articular cartilage but also exhibit a 50% lower coefficient of friction (COF). The exceptional cartilage-like properties of the PAMPS/P(NIPAAm-co-AAm) DN hydrogels makes them candidates for synthetic cartilage grafts for chondral defect repair, even in load-bearing regions of the body.

PMID:
31009565
DOI:
10.1021/acs.biomac.9b00237

https://www.economist.com/middle-east-and-africa/2019/03/30/the-rush-to-avert-a-second-disaster-after-floods-in-mozambique

https://reliefweb.int/report/mozambique/mozambique-cyclone-idai-floods-situation-report-no-6-7-april-2019

SITUATION OVERVIEW

As of 7 April, the official death toll remained at 602 people. The number of houses recorded as destroyed or damaged, meanwhile, increased to 239,682, including 111,163 houses totally destroyed, 112,735 partially destroyed, and 15,784 flooded. There has reportedly been an increase in women-headed households as a result of the disaster, according to humanitarian partners and authorities, although exact numbers are yet to be verified or confirmed.

At least 160,927 people were sheltering in 164 sites across Manica (43); Sofala (113); Tete (5) and Zambezia (3), according to government figures. The number of sites reported in Manica more than doubled from 6 to 7 April (20 to 43), while the number of people accommodated in the sites in Manica increased from 13,115 to 24,419. The previous reported figures for Manica had not included data on several sites, including in Sussundenga district and particularly in Dombe posto.

Some 389 new cholera cases were recorded on 7 April, bringing the total number of registered cases to 3,161, according to the Ministry of Health. Beira recorded the majority of the new cases (246 cases recorded on 7 April), followed by Nhamatanda (75 cases), Buzi (42 cases) and Dondo (26 cases). More than 593,000 people were vaccinated as of 7 April, representing 73 per cent of the people targeted.

HIGHLIGHTS

• Distribution of seeds for the winter harvest will start on 8 April in Manica province.

• More than 756,200 individuals have received food assistance since Cyclone Idai made landfall, including 10,000 people receiving ready-to-eat meals in Beira city.

• The number of houses recorded as destroyed or damaged has increased to 239,682.

• Some 389 new cases of cholera were reported on 7 April, in Beira (246 cases), Nhamatanda (75 cases) and Dondo (26 cases) and Buzi (42 cases), including one death.

• At least 593,000 people had received the Oral Cholera Vaccine as of 7 April, representing 73 per cent of the total target.

https://www.oxfam.org/en/emergencies/crisis-syria

https://www.trtworld.com/middle-east/iran-expands-evacuations-as-rains-worsen-floods-25601

https://www.trtworld.com/middle-east/floods-hit-40-000-displaced-people-in-northwest-syria-un-25504

 

http://www.gdacs.org/default.aspx

https://reliefweb.int/map/iran-islamic-republic/iran-floods-emergency-response-coordination-centre-ercc-echo-daily-map

https://www.who.int/emergencies/cyclone-idai/events-as-they-happen

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